Kyushu University Academic Staff Educational and Research Activities Database
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GUANGQI CHEN Last modified date:2019.06.13

Professor / Geotechnic, Department of Civil & Structural Engineering, Graduate School of Engineering
Division for Experimental Natural Science
Faculty of Arts and Science


Graduate School
大学院共通教育科目
Undergraduate School
Administration Post
Other


Homepage
www.civil.kyushu-u.ac.jp/bousai
Phone
092-802-6006
Fax
092-802-6006
Academic Degree
Doctor of Science (The University of Tokyo)
Country of degree conferring institution (Overseas)
No
Field of Specialization
Geotechnical engineering, Geo-disaster protection, Geophysics
Total Priod of education and research career in the foreign country
00years00months
Outline Activities
1. Research
Current major research interests (since the Nov. of 1993)
(1) Numerical simulation methods and their practical applications to natural disaster prevention and mitigation
(i) 3-D program development of DDA (Discontinuous Deformation Analysis)
(ii) 3-D program development of MM (Manifold Method)
(iii) 3-D program development of DDA coupled with SPH (Smoothed Particle Hydrodynamics)
(iv) 3-D program of debris flow simulation based on Takahashi model
(2) Risk management in natural disaster prevention
(i) Landslide risk assessment and management
(ii) Liquefaction risk assessment and management
(iii) Risk assessment of climate change due to global warming
(3) Hazard map and risk map of landslide
(4) Hazard map of landslide dam
(5) Earthquake induced landslide disaster chain

I was also engaged in the scientific studies in the field of crustal deformation and earthquake prediction from 1982 to 1993.

2. Education
I am a supervisor of Ph.D candidates.
Research
Research Interests
  • DEVELOPMENT OF A PRACTICAL SYSTEM FOR SIMULATING EARTHQUAKE GROUND MOTIONS PAYING ATTENTION TO VOLCANIC ZONE AND ASPERITY ON A FAULT
    keyword : System, seismic wave, falut, PGA
    2015.01~2017.11.
  • Study on Slop Reinforcement and Landslide Warning System Using a New Type of Anchor with Negative Poisson's Ratio 
    keyword : Negative Poisson's Ratio, Anchor, Slop Reinforcement, Landslide Warning System
    2015.01~2016.12.
  • Development of a new prediction system for debris flow its practical applications to disaster mitigation
    keyword : Development, prediction, system, debris flow, applications, disaster mitigation
    2013.04~2017.03.
  • Study on mechanism of arch effect of particle material and its application to disaster mitigation
    keyword : mechanism, arch effect, particle material, application, disaster mitigation
    2013.04~2017.03.
  • Development of solid and fluid coupling simulation method using DDA and SPH and its practical applications
    keyword : Development, solid, fluid, coupling, simulation, method, DDA, SPH, applications
    2013.04~2017.03.
  • Development of prediction system for earthquake induced landslide dam
    keyword : Development, prediction system、 earthquake, landslide dam
    2013.04~2017.03.
  • Development of risk assessement method for earthquake induced landslide disaster chain
    keyword : Development, risk, assessment, earthquake, landslide, disaster, chain
    2013.04~2017.03.
  • Development of a real-time warning system for rain fall induced landslides and development of practical numerical simulation program for estimating landslide movements

    keyword : Development, real-time warning system, rainfall, landslide, numerical simulation, movements
    2012.04~2015.03.
  • Stability analysis of breakwater by using numerical simulations under considering seepage induced by tsunami

    keyword : Stability analysis,breakwater ,numerical simulations,seepage ,tsunami
    2012.04~2013.03.
  • Study on development of 3-d Manifold Method (MM) and its applications to the crust tectonic stress
    keyword : Manifold Method , earthquake, crust, movement, stress
    2010.04~2013.03.
  • Study on development of 3-d Discontinous Deformation analysis (DDA) and its applications to landslide simulation
    keyword : landslide, earthquake,DDA
    2010.04~2013.03.
  • Hazard maps and risk maps of landslide by using GIS
    keyword : landslide, earthquake, Hazard, map, risk, GIS
    2010.04~2016.03.
  • study on high speed and long run-out movement of landslides by considering earthquake trampoline effect
    keyword : landslide, earthquake, risk, assessment, adaptation, trampoline, high speed, long run-out
    2010.04~2016.03.
  • Coastal hazards induced by global climate change: an assessment of impacts, risks, and adaptation strategies
    keyword : global warming, climate change, risk, assessment, adaptation strategies
    2005.04~2010.03.
  • Study on the prediction of landslide induced by railfall
    keyword : landslide, rainfall, prediction, index of rainfall, effective rainfall
    2007.04~2012.03.
  • Study on landslide risk management
    keyword : landslide, risk, management
    2005.05~2013.03.
  • Study on the high speed and long distance movement mechanism of the landslides induced by an earthquake
    keyword : high speed, long distance movement, mechanism, landslides, earthquake
    2008.08~2013.03.
  • Hazard map and risk map of landslide using GIS
    keyword : hazard map, risk map, practical technique, landslide
    2006.04~2010.03.
  • Development of the practical risk analysis and assessment techniques for landslides by considering the locality of slope environment
    keyword : locality, special properties, earthquake hazard curve, rainfall hazard curve
    2007.04~2010.03.
  • Study on the numerical simulation methods for geotechnical engineering
    keyword : numerical simulation, Manifold Method, Discontinuous Deformation Analysis
    1993.11~2012.01Numerical Analysis for Rock Mechanics.
Current and Past Project
  • Development of a real-time warning system for rain fall induced landslides and development of practical numerical simulation program for estimating landslide movements
Academic Activities
Books
1. GUANGQI CHEN, Yuzo Ohnishi, Lu Zheng, Takeshi Sasaki, Frontiers of Discontinuous Numerical Methods and Practical Simulations in Engineering and Disaster Prevention, CRC Press, 552頁, 2013.08, Analysis of large deformation, rigid body movement and strain or stress for discontinuous materials is often required for project designs and plans in the fields of engineering and disaster prevention. Many numerical simulation and analysis methods have been developed for the requirement from science and technology people since 1970s. Among them, Discontinuous Deformation Analysis (DDA), Numerical Manifold Method (NMM), Key Block Theory (KB), Distinct/Discrete Element Methods (DEM), Moving Particles Semi-implicit Method (MPS) and Smoothed Particle Hydrodynamics Method (SPH) are typical effective methods and have drawn more and more attention of the researchers in many different fields. The discrete analysis is more natural than continuum analysis to handle geologic materials which we use as engineering materials. Advancement of computers and introduction of unique ideas helped us to develop many useful new numerical methods as listed above. Frontiers of Discontinuous Numerical Methods and Practical Simulations in Engineering and Disaster Prevention contains 14 keynote papers, 54 full papers and 4 extended abstracts presented at the 11th International Conference on Analysis of Discontinuous Deformation (ICADD-11, Fukuoka, Japan, 27-29 August 2013). The contributions cover the latest advances in all aspects of discontinuous numerical methods, from theory to practice, including new ideas and the latest developments. The main schemes are on DDA, NMM and KB following the tradition of the conference series. Meanwhile, DEM, MPS, SPH, Meshless Methods and some other numerical methods are also included. The book is a must-have for those academics and professionals interested in the state-of-the-art in technology and numerical methods related to the above mentioned methods..
2. GUANGQI CHEN, Earthquake Research and Analysis - Statistical Studies, Observations and Planning, InTech - Open Access Publisher, Chapter 18 Earthquake induced a chain disasters: 383-416, 2012.03, 地震による斜面崩壊に起因する二次災害連鎖を体系化したリスク評価および防災対策

Chapter 18: Earthquake induced a chain disasters
本のタイトル: Earthquake Research and analysis, ISNB 978-953-51-0134-5.
3. Guangqi Chen, Naomichi YOKOYA, Yoshito KITAZONO, Yoshito KITAZONO and Noritaka ARAMAKI, The New Technology Frontier: Adcanced Preventive Measures against Landslides, Touka Shobo, p. 277, 2011.11.
4. Maotian Luan, Kouki Zen, Guangqi Chen, Tingkai Nian, Kiyonobu Kasama, Recent Development of Geotechnical and Geo-Environmental Engineering in Asia, Dalian University of Technology Press, p. 617, 2006.11.
Reports
1. 分担執筆, Technical Report by Japanese Domestic Committee on Geotechnics of Particulate Media Technical Committee (TC35), 2005.08.
Papers
1. Xinyan Peng, Guangqi Chen, Pengcheng Yu, Yingbin Zhang, Jinmei Wang, Improvement of joint definition and determination in three-dimensional discontinuous deformation analysis, Computers and Geotechnics, 10.1016/j.compgeo.2019.02.016, 110, 148-160, 2019.06, Joint property in three-dimensional discontinuous deformation analysis (3-D DDA) is crucial. The joint property in a contact relies upon just one of the contacting objects in original 3-D DDA, which is not always sufficiently accurate and can even yield unreasonable results. To overcome the limitations in original 3-D DDA, an improved joint definition and determination method that simultaneously considers the joint properties of both connected objects for contacts is proposed, which permits the applied joint parameters to change in the simulation. Several numerical examples are evaluated to demonstrate the advantage and applicability of the proposed method. The simulation results computed by the improved 3-D DDA accord well with the analytical expectations and physical reality, while the original 3-D DDA shows unphysical results. The improved 3-D DDA can provide more reliable information in rockslide disaster prevention and mitigation because joint parameters in a contact can be chosen appropriately in real time during simulations. Therefore, the improved 3-D DDA is more applicable and accurate, which can be further extended to more generalized theoretical and engineering problems..
2. Wei Wang, Kunlong Yin, Guangqi Chen, Bo Chai, Zheng Han, Jiawen Zhou, Practical application of the coupled DDA-SPH method in dynamic modeling for the formation of landslide dam, Landslides, 10.1007/s10346-019-01143-5, 16, 5, 1021-1032, 2019.05, Landslides along river margins can cause permanent or temporal landslide dams and dammed-lakes, threatening people’s life and properties. Investigation of the formation process for the landslide dam is crucial for emergency response and mitigation planning. However, the formation process modeling for a practical case usually involves large scale and complicates geometry. To overcome the computation complexity and promote efficiency, a series of practical techniques have been proposed. Firstly, an Open Channel Model with Steady Flow (OCMSF) has been developed to naturally produce a river flow. Then, a three-stage simulation strategy has been proposed to fulfill the large-scale practical modeling. In specific, stage 1 generated a steady open channel flow using SPH method. In stage 2, the DDA method is used to simulate landslide movement until the mass reaches the river. In stage 3, the formation process with landslide-river interaction is realized using a coupled DDA-SPH method. The formation process of the Yangjiagou landslide dam was selected as the practical application. Simulation results showed the Yangjiagou landslide reached the river with a front velocity of 22 m/s in around 8 s and formed a dam with estimated volume of 500,000 m
3
, which is consistent with the site investigation. It is thus demonstrated the applicability and performance of the coupled method and numerical techniques in modeling practical landslide dam case..
3. Longxiao Guo, Tonglu Li, Guangqi Chen, Pengcheng Yu, Xinyan Peng, Deguang Yang, A method for microscopic unsaturated soil-water interaction analysis based on DDA, Computers and Geotechnics, 10.1016/j.compgeo.2018.12.002, 108, 143-151, 2019.04, Unsaturated soil is a three-phase discontinues system, and microscopic analysis can provide an intrinsic understanding for macroscopic mechanical behavior of the soil. Discontinuous Deformation Analysis (DDA) has the advantage for analyzing the material like granular aggregates. Based on capillary mechanics, a newly developed algorithm is applied in conventional DDA code, which treats a DDA element as an ideal soil particle and exerts capillary force among elements. Then, to validate the extended method, an ideal microscopic soil model is established, and the simulation results are in good agreement with typical analytical solutions. It indicates that the developed DDA is reliable and applicable to explore unsaturated soil behaviors microscopically..
4. Xinyan Peng, Guangqi Chen, Pengcheng Yu, Yingbin Zhang, Longxiao Guo, Cungen Wang, Xiao Cheng, Hui Niu, Parallel computing of three-dimensional discontinuous deformation analysis based on OpenMP, Computers and Geotechnics, 10.1016/j.compgeo.2018.11.016, 106, 304-313, 2019.02, The computing efficiency of three-dimensional discontinuous deformation analysis (3D-DDA) needs to be improved for large-scale simulations. Among all the subroutines of 3D-DDA, the equation solver is very time-consuming. To accelerate the equation-solving process, this paper proposes implementing the parallel block Jacobi (BJ) and preconditioned conjugate gradient (PCG) iterative solvers into the original 3D-DDA based on OpenMP. The calculation accuracy and computational efficiency are studied by several numerical examples, demonstrating that the modified 3D-DDA with parallel BJ or PCG solver exhibits much higher execution efficiency with satisfactory correctness. The maximum speedup ratio is up to 5.1 for the cases studied..
5. Xinyan Peng, Pengcheng Yu, Yingbin Zhang, Guangqi Chen, Applying modified discontinuous deformation analysis to assess the dynamic response of sites containing discontinuities, Engineering Geology, 10.1016/j.enggeo.2018.10.011, 246, 349-360, 2018.11, The accurate consideration of seismic wave propagation through discontinuous media is crucial in rock engineering. Discontinuous deformation analysis (DDA), with the ability to study discontinuity behaviors, is modified by incorporating a seismic input method based on a viscous boundary and the free-field theory. After confirming the accuracy of the modified DDA using several verification examples, two practical applications, (1) the extreme ground motion during the 2008 Iwate–Miyagi earthquake, Japan, and (2) the Donghekou landslide induced by the 2008 Wenchuan earthquake, China, are simulated and reproduced by the modified DDA. The results show that seismic wave propagation through discontinuous media can be accurately simulated by the modified DDA. Further, the simulation results indicate that discontinuities are critical in the dynamic response of structures. Conclusively, the modified DDA provides an alternative approach for analyzing the dynamic response of sites containing discontinuities..
6. Zhujun Li, Shuguang Liu, Hong Zhang, Guangqi Chen, Wei Wu, Hehua Zhu, Xiaoying Zhuang, Wei Wang, Simulating the damage extent of unreinforced brick masonry buildings under boulder impact using three-dimensional discontinuous deformation analysis (3-D DDA), Engineering Failure Analysis, 10.1016/j.engfailanal.2018.07.013, 93, 122-143, 2018.11, The main material of brick masonry buildings is discontinuous masonry material. This study presents a critical review of the damage characteristics of masonry and the methods for studying the behavior of masonry. The damage extent of brick masonry buildings under boulder impact is analyzed using an approach based on three-dimensional discontinuous deformation analysis (3-D DDA). A “block-joint” model is established to represent the brick and mortar of the building, which is based on the discontinuous characteristics of the masonry material. On this basis, a benchmark model is used to validate the 3-D DDA. Using this approach, the velocity distribution and several displacements of key points of the building blocks are obtained to compare the damage extent of the building under six different cases that consider in-plane or out-of-plane boulder impacts to the building at different heights. The size and material parameters of the building model are based on the most common buildings in the field of investigation. These results can be used to show the failure process of buildings on a continuous basis or to quantitatively compare the damage extent of different types of buildings. By analyzing the force condition of the basic element blocks, the results demonstrate that the damage extent of the building is related to the impact direction, impact height, location relationship between the damaged part and the impact position, and constraint condition..
7. Hong Zhang, Shu guang Liu, Wei Wang, Lu Zheng, Ying bin Zhang, Yan qiang Wu, Zheng Han, Yan ge Li, Guangqi Chen, A new DDA model for kinematic analyses of rockslides on complex 3-D terrain, Bulletin of Engineering Geology and the Environment, 10.1007/s10064-016-0971-6, 77, 2, 555-571, 2018.05, Landslides are common phenomena in mountainous regions worldwide. Over the past two decades, catastrophic rockslides in mountainous regions have caused serious damage and fatalities. To develop effective preventive countermeasures, it is important to estimate the kinematic behavior of displaced masses after slope failures, such as the velocity, run-out distance, and extent. Discontinuous deformation analysis (DDA) is an appropriate tool to analyze the dynamics, kinematics, and deformability of a block assembly. Many studies have reported applications of DDA to kinematic analyses of rockslides on two-dimensional (2-D) terrain. However, because of the restrictions of numerical techniques, few kinematic analyses of rockslides on three-dimensional (3-D) terrain have been performed using DDA. This study developed a new DDA model for the analysis of rockslides on 3-D terrain. First, contact treatment techniques for the 3-D model were developed to create an accurate and efficient computational scheme. The new model was then verified by the benchmark tests on the four basic types of block motion on 3-D terrain. Finally, the new model was applied to a designed rockslide with complex terrain to demonstrate its practical applicability. The results indicate that the new 3-D DDA model is an effective tool to analyze 3-D rockslides and could potentially be used to optimize protection designs for rockslides..
8. G. Samodra, Guangqi Chen, J. Sartohadi, Kiyonobu Kasama, Generating landslide inventory by participatory mapping
an example in Purwosari Area, Yogyakarta, Java, Geomorphology, 10.1016/j.geomorph.2015.07.035, 306, 306-313, 2018.04, This paper proposes an approach for landslide inventory mapping considering actual conditions in Indonesia. No satisfactory landslide database exists. What exists is inadequate, focusing, on data response, rather than on pre-disaster preparedness and planning. The humid tropical climate also leads a rapid vegetation growth so past landslides signatures are covered by vegetation or dismantled by erosion process. Generating landslide inventory using standard techniques still seems difficult. A catalog of disasters from local government (village level) was used as a basis of participatory landslide inventory mapping. Eyewitnesses or landslide disaster victims were asked to participate in the reconstruction of past landslides. Field investigation focusing on active participation from communities with the use of an innovative technology was used to verify the landslide events recorded in the disaster catalog. Statistical analysis was also used to obtain the necessary relationships between geometric measurements, including the height of the slope and length of run out, area and volume of displaced materials, the probability distributions of landslide area and volume, and mobilization rate. The result shows that run out distance is proportional to the height of the slope. The frequency distribution calculated by using non-cumulative distribution empirically exhibits a power law (fractal statistic) even though rollover can also be found in the dataset. This cannot be the result of the censoring effect or incompleteness of the data because the landslide inventory dataset can be classified as having complete data or nearly complete data. The so-called participatory landslide inventory mapping method is expected to solve the difficulties of landslide inventory mapping and can be applied to support pre-disaster planning and preparedness action to reduce the landslide disaster risk in Indonesia. It may also supplement the usually incomplete data in a typical landslide inventory..
9. Guangqi Chen, Manchao He, Fusong Fan, Rock burst analysis using DDA numerical simulation, International Journal of Geomechanics, 10.1061/(ASCE)GM.1943-5622.0001055, 18, 3, 2018.03, A rock burst can cause a serious disaster. For the mitigation of rock burst-induced disaster, the possibility assessment of a rock burst for an underground excavation is a key undertaking and also a great challenge because rock burst failure involves a dynamic and large deformation process. In this paper, a numerical simulation method of rock burst using discontinuous deformation analysis (DDA) is proposed by showing the advantage of DDA in handling the large deformation of this dynamic process. First, the problem of using the number of the adjacent boundary in the original algorithm of the DDA program was determined and solved, which is critical and important in analyzing artificial mesh models. The DDA model was used for simulating a rock burst process and was verified by a true triaxial test in which the critical stress for rock burst had been clarified. Then, the effects of rock hardness and brittleness on critical stresses were clarified quantitatively. The critical stresses of a rock burst were estimated for rocks with various values of the elastic modulus, Poisson's ratio, cohesion, friction angle, and tension strength. Finally, a strategy is proposed for examining the critical depth of a rock burst for various types of rocks under different tectonic levels. Rocks are classified by the mechanical properties of them, such as elastic modulus, Poisson's ratio, cohesion, friction angle, and tensile strength. The depth condition was converted to initial stress. The tectonic condition was represented by the ratio of horizontal-to-vertical components of the initial stress. Through a large set of simulations, the critical depths of rock bursts in seven types of rocks were estimated for different tectonic levels. The results show that the proposed rock burst analysis using DDA simulation is effective and useful..
10. Zheng Han, Weidong Wang, Yange Li, Jianling Huang, Bin Su, Chuan Tang, Guangqi Chen, Xia Qu, An integrated method for rapid estimation of the valley incision by debris flows, Engineering Geology, 10.1016/j.enggeo.2017.11.007, 232, 34-45, 2018.01, Valley incision by debris flow is an important process in creating and maintaining the topography of a valley, in addition to explaining the significant growth of the magnitudes of debris flow hazards. In this paper, we introduce a semi-empirical method to quantitatively estimate the valley incision process by debris flows over complex bed surface. We first reproduce natural bed surface across the valley by a polyline, and use a hydrograph of discharge versus time to represent the temporal variation of debris flow process. The presented method subsequently predicts the debris flow behavior over an irregular bed surface. A dynamic erosion law considers the solved debris flow behavior and estimates an instantaneous erosion rate. Finally, the accumulative incision depth of bed sediment is calculated, reshaping the initial bed surface across the valley. The presented method is simple and therefore notably beneficial for practical work. The performance of the proposed method has been tested using two case study applications. Results demonstrate that the presented method estimates comparable incision depth as revealed in the in-situ survey and the numerical simulation..
11. Han Z., Li Y.G., Huang J.L., Chen G.Q., Xu L.R., Numerical simulation for run-out extent of debris flows using improved Cellular Automaton model. Bulletin of engineering geology and environments, Bulletin of Engineering Geology and the Environment, 10.1007/s10064-016-0902-6, 76, 3, 961-974, 2017.08, Numerical simulation of the debris-flow process is commonly based on the shallow water equations. However, as a two-phase anisotropic mixture, debris flows display complex rheological behavior, making it difficult to model or to simulate these using standard approaches. In this paper, an improved cellular automaton (CA) model is developed for simulating the extent of debris-flow run-out. The CA model consists of three essential components: cellular space, lattice relation, and transition function. A two-dimensional rectangular cellular space is generated from mesh grid in the digital terrain model data, and the Moore neighborhood type is selected as the lattice relation. We also use a transition function based on a Monte Carlo iteration algorithm to automatically search the flow direction and flow routine. Specifically, this new transition function combines the topography function and persistence function (due to the flow inertia), and is advanced in its ability to avoid certain illogical lateral spreading due to abrupt changes in topography. In addition, in contrast to previous studies, in the present work, we regressed the persistence function from a well-documented flume experiment, rather than using a manipulated constant value as described in earlier empirical studies. Our results show that the debris-flow persistence function is closely related to the channel slope. It approximates the law of cosines at a steep slope and Gamma law at a gentle slope. To illustrate the performance of the improved CA model, we selected the 2010 Yohutagawa debris-flow event in Japan as a case study. Our results show that the simulated deposition perimeter pattern and run-out distance are in high accordance with the data from in situ investigation..
12. Wei Wang, Guangqi Chen, Yingbin Zhang, Lu Zheng, Hong Zhang, Dynamic simulation of landslide dam behavior considering kinematic characteristics using a coupled DDA-SPH method, Engineering Analysis with Boundary Elements, 10.1016/j.enganabound.2017.02.016, 80, 172-183, 2017.07, Landslide with significant volume and considerable velocity may block the river stream in the hillslope-channel coupling system, forming the natural dam and the dammed-lake behind. Previous studies predicted the behavior of landslide dams using different dimensionless indexes derived from the geomorphological characteristics. However, the kinematic characteristics of the river and landslide also play key roles in the dam formation. To consider the kinematic characteristics, the dynamic simulation of the dam behavior (formation and failure) involves three problems: (i) the movement of the river flow, (ii) the landslide movement and (iii) the landslide-river interaction. In this study, the movement of the river flow is simulated by a particle recycling method (PRM) under the framework of smoothed particle hydrodynamics (SPH). The discontinuous deformation analysis (DDA) is used to model the landslide movement. The interaction between the solid and fluid phases is achieved by the coupled DDA-SPH method. The proposed methods have been implemented in the numerical code, and a series of examples were employed for validations. The importance of the kinematic characteristics for the dam behavior was demonstrated by a series of numerical scenarios..
13. Yanqiang Wu, Guangqi Chen, Zaisen Jiang, Long Zhang, Hong Zhang, Fusong Fan, Zheng Han, Zhenyu Zou, Liu Chang, Layue Li, Research on fault cutting algorithm of the three-dimensional numerical manifold method, International Journal of Geomechanics, 10.1061/(ASCE)GM.1943-5622.0000655, 17, 5, 2017.05, The fault cutting algorithm is important when applying the three-dimensional numerical manifold method to engineering simulation. This paper presents a primary approach to the fault cutting algorithm, including data structures, fault cutting procedures, and some basic computing algorithms. First, the data structures of the physical elements and mathematical covers are proposed as single linked lists and linked list arrays, respectively. This reduces the complexity of the algorithm and increases the efficiency when connecting physical elements to covers. Second, a strategy of recording cutting traces between every two faults to ensure that the model agrees with the actual situation was proposed. This strategy also reduces the complexity and improves the efficiency. Third, the mathematical covers and physical elements are cut with all faults independently to process complete cutting instances in a multiblock form and incomplete cutting instances without forming any new irrational block. Finally, four cutting examples are presented that demonstrate that the proposed fault cutting algorithm is correct and useful..
14. Guruh Samodra, Guangqi Chen, Junun Sartohadi, Kiyonobu Kasama, Comparing data-driven landslide susceptibility models based on participatory landslide inventory mapping in Purwosari area, Yogyakarta, Java, Environmental Earth Sciences, 10.1007/s12665-017-6475-2, 76, 4, 2017.02, There are different approaches and techniques for landslide susceptibility mapping. However, no agreement has been reached in both the procedure and the use of specific controlling factors employed in the landslide susceptibility mapping. Each model has its own assumption, and the result may differ from place to place. Different landslide controlling factors and the completeness of landslide inventory may also affect the different result. Incomplete landslide inventory may produce significance error in the interpretation of the relationship between landslide and controlling factor. Comparing landslide susceptibility models using complete inventory is essential in order to identify the most realistic landslide susceptibility approach applied typically in the tropical region Indonesia. Purwosari area, Java, which has total 182 landslides occurred from 1979 to 2011, was selected as study area to evaluate three data-driven landslide susceptibility models, i.e., weight of evidence, logistic regression, and artificial neural network. Landslide in the study area is usually affected by rainfall and anthropogenic activities. The landslide typology consists of shallow translational and rotational slide. The elevation, slope, aspect, plan curvature, profile curvature, stream power index, topographic wetness index, distance to river, land use, and distance to road were selected as landslide controlling factors for the analysis. Considering the accuracy and the precision evaluations, the weight of evidence represents considerably the most realistic prediction capacities (79%) when comparing with the logistic regression (72%) and artificial neural network (71%). The linear model shows more powerful result than the nonlinear models because it fits to the area where complete landslide inventory is available, the landscape is not varied, and the occurence of landslide is evenly distributed to the class of controlling factor..
15. Long Zhang, Guangqi Chen, Yanqiang Wu, Han Jiang, Stochastic ground-motion simulations for the 2016 Kumamoto, Japan, earthquake 2016 Kumamoto earthquake sequence and its impact on earthquake science and hazard assessment 4. Seismology, Earth, Planets and Space, 10.1186/s40623-016-0565-3, 68, 1, 2016.12, On April 15, 2016, Kumamoto, Japan, was struck by a large earthquake sequence, leading to severe casualty and building damage. The stochastic finite-fault method based on a dynamic corner frequency has been applied to perform ground-motion simulations for the 2016 Kumamoto earthquake. There are 53 high-quality KiK-net stations available in the Kyushu region, and we employed records from all stations to determine region-specific source, path and site parameters. The calculated S-wave attenuation for the Kyushu region beneath the volcanic and non-volcanic areas can be expressed in the form of Q s = (85.5 ± 1.5)f 0.68±0.01 and Q s = (120 ± 5)f 0.64±0.05, respectively. The effects of lateral S-wave velocity and attenuation heterogeneities on the ground-motion simulations were investigated. Site amplifications were estimated using the corrected cross-spectral ratios technique. Zero-distance kappa filter was obtained to be the value of 0.0514 ± 0.0055 s, using the spectral decay method. The stress drop of the mainshock based on the USGS slip model was estimated optimally to have a value of 64 bars. Our finite-fault model with optimized parameters was validated through the good agreement of observations and simulations at all stations. The attenuation characteristics of the simulated peak ground accelerations were also successfully captured by the ground-motion prediction equations. Finally, the ground motions at two destructively damaged regions, Kumamoto Castle and Minami Aso village, were simulated. We conclude that the stochastic finite-fault method with well-determined parameters can reproduce the ground-motion characteristics of the 2016 Kumamoto earthquake in both the time and frequency domains. This work is necessary for seismic hazard assessment and mitigation..
16. Guruh Samodra, Guangqi Chen, Junun Sartohadi, Danang Sri Hadmoko, Kiyonobu Kasama, Muhammad Anggri Setiawan, Rockfall susceptibility zoning based on back analysis of rockfall deposit inventory in Gunung Kelir, Java, Landslides, 10.1007/s10346-016-0713-7, 13, 4, 805-819, 2016.08, A rockfall susceptibility based on trajectory-energy/velocity approach needs release area or rockfall source. However, identification of rockfall source is not always possible for some areas in Indonesia. This paper presents a rockfall susceptibility zoning based on back analysis technique of rockfall deposit inventory in Gunung Kelir, Java. There were several steps in the rockfall susceptibility zoning: (1) rockfall deposit inventory, (2) rockfall simulation based on back analysis of rockfall deposit inventory, (3) sensitivity analysis, and (4) rockfall susceptibility zoning. The result suggests that the travel distance is affected by the spatial distribution of rockfall source, lithology or surface material, and topography (angle of slope and angle of aspect). Final trajectories were employed to generate landslide susceptibility map which may allow a policy maker to have an advanced consideration to achieve specified risk measures and evaluation of their cost efficiency to optimize budget and design. Application of rockfall susceptibility zoning based on back analysis of rockfall deposits is efficient where rockfall source information is unavailable..
17. Hong Zhang, Shu guang Liu, Guangqi Chen, Lu Zheng, Ying bin Zhang, Yan qiang Wu, Pei deng Jing, Wei Wang, Zheng Han, Gui hui Zhong, Sha Lou, Extension of three-dimensional discontinuous deformation analysis to frictional-cohesive materials, International Journal of Rock Mechanics and Mining Sciences, 10.1016/j.ijrmms.2016.03.021, 86, 65-79, 2016.07, This paper extends three-dimensional discontinuous deformation analysis (3-D DDA) to model the frictional-cohesive failure behavior of geotechnical materials and structures. Firstly, a new contact detection scheme was developed to successfully identify the dominant sub-contacts and areas of the joints between arbitrarily shaped polyhedral blocks. Secondly, a modified joint contact model subjected to the Mohr-Coulomb failure criteria based on distributed cohesion instead of concentrated cohesion, was proposed to ensure the accuracy of the simulation by 3-D DDA. Thirdly, the extended 3-D DDA was verified by three examples, including joint contact detection, critical stability and failure mode of a system of polyhedral blocks. Finally, the complete failure process involving large displacement and rotation of multiple interaction blocks is exhibited dynamically. Overall, these examples exhibit that the extended 3-D DDA is now capable of accurately modeling the failure behavior of frictional-cohesive materials and structures, so as to optimize the material and structure stabilization or protection design..
18. GUANGQI CHEN, Fusong FAN, Stability analysis of toppling slope using the extended NMM , American Rock Mechanics Association , 6ページ, 2016.06, The original numerical manifold method (NMM) is extended for stability analysis of a toppling slope with complex sliding surface and cohesion and tensile strengths existing in discontinuities. The extended NMM is shown effective by reproducing a centrifuge test. With NMM simulation, the commonly used Goodman and Bray’s analytical method is shown adaptable to a toppling slope model with a simple sliding surface without cohesion and tensile strengths in the discontinuities. It is shown that the deformation of the sliding body has no significant effect on the result. The relationship between dip angle and critical friction angle is investigated. A real toppling slope is simulated and the necessary cohesion and friction angle are verified. .
19. Suhua ZHOU, GUANGQI CHEN, Distribution Pattern of Landslides Triggered by the 2014 Ludian Earthquake of China: Implications for Regional Threshold Topography and the Seismogenic Fault Identification, ISPRS International Journal of Geo-Information , doi:10.3390/ijgi5040046, 22ページ, 2016.05.
20. Wei Wang, GUANGQI CHEN, 3D numerical simulation of debris-flow motion using SPH method incorporating non-Newtonian fluid behavior, Natural Hazards, 81, 3, 2016.04, Flow-type landslide, such as debris-flow, often exhibits high velocity and long run-out distance. Simulation on it benefits the propagation analysis and provides solution for risk assessment and mitigation design. Previous studies commonly used shallow water assumption to simulate this phenomenon, ignoring the information in vertical direction, and the Bingham model to describe constitutive law of non-Newtonian fluid can cause numerical divergence unless necessary parameter is defined. To address the issue, the full Navier–Stokes equations are adopted to describe the dynamics of the flow-type landslides. Additionally, the general Cross model is employed as the constitutive model, which ensures the numerical convergence. Rheological parameters are introduced from the Bingham model and the Mohr–Coulomb yield criterion. Subsequently, the governing equations incorporating the modified rheological model are numerically built in the smoothed particle hydrodynamics (SPH) framework and implemented into the open-source DualSPHysics code. To illustrate its performance, the 2010 Yohutagawa debris-flow event in Japan is selected as a case study. Parameters regarding the debris magnitude, i.e., the front velocity and section discharge, were also well analyzed. Simulated mass volume and deposition depth at the alluvial fan are in good agreements with the in situ observation. On the basis of the results, the developed method performs well to reproduce the debris-flow process and also benefits the analysis of flow characteristics, affected area for risk assessment and mitigation design..
21. Wei Wang, GUANGQI CHEN, Analysis of landslide-generated impulsive waves using a coupled DDA-SPH method, Engineering Analysis with Boundary Elements, 64, 2016.04, Large impulsive waves generated by slope failures and a subsequent landslide in a reservoir area may lead to serious damage to the dam, shoreline properties and lives. Therefore, analysis of landslide-generated impulsive waves is of significant importance for hazard prevention and reduction. There are three key points for analyzing this problem: (i) the landslide run-out, (ii) the free surface flow and (iii) the landslide-water interaction process. The Discontinuous Deformation Analysis (DDA) method was previously developed to investigate discontinuous block movements, while the Smoothed Particle Hydrodynamics (SPH) method was used mostly to model free surface flow. However, the solid–fluid interaction is seldom considered in the respective fields, which greatly restricts their applications. For this reason, the coupled DDA-SPH method was proposed in this study to solve the solid–fluid interaction problem. To validate this approach, this study considered a wedge sliding along an inclined plane and interacting with the water body. The corresponding Heinrich’s experimental results were adopted to evaluate the accuracy of the coupled method in modeling the landslide movement and wave profile, proving that the landslide motion and wave profiles could be captured accurately by the coupled method. Finally, the effect of the governing parameters on the wave amplitude was discussed.
22. Wei Wang, GUANGQI CHEN, Modeling of landslide generated impulsive waves considering complex topography in reservoir area, Environmental Earth Sciences, 75, 2016.04.
23. Suhua ZHOU, GUANGQI CHEN, GIS-Based Integration of Subjective and Objective Weighting Methods for Regional Landslides Susceptibility Mapping, Sustainability, Vol. 8, No.4, 2016.04.
24. Suhua ZHOU, GUANGQI CHEN, A Combined Weight of Evidence and Logistic Regression Method for Susceptibility Mapping of Earthquake-induced Landslides: A Case Study of the April 20, 2013 Lushan Earthquake, China, Acta Geologica Sinica (English Edition), Vol. 90, No.2, 2016.04, This Paper proposes a combined method LE-WoE of LE (Logistic Regression) and WoE (Weight of Evidence) for landslide susceptibility mapping by taking their individual merits and overcoming their limitations. By practical applications, the results show that the combined LR-WoE method is of higher accuracy than both the individual method. It can be concluded that the new combined method LE-WoE can provide a promising level of accuracy for earthquake induced landslide susceptibility mapping..
25. Zhao Xingquan, Zhang Yingbin, GUANGQI CHEN, Discontinuous Deformation Analysis Method and Its Applications to Disaster Prevention, Journal of Southwest Jiaotong University, 51, 2, 300-312, 2016.04.
26. GUANGQI CHEN, Modeling of landslide generated waves in Three Gorges Reservoir, China using SPH method, Japanese Geotechnical Society Special Publication, 2016.02.
27. GUANGQI CHEN, Integration of Bivariate Statistics and Analytic Hierarchy Process Methods in Regional Landslides Susceptibility Mapping: A case study of Tsushima Island, Japan, Proceedings of the symposium on advanced technology of prediction and preventive measures of landslides, 2015.12.
28. GUANGQI CHEN, Numerical modeling of landslide generated impulsive waves using coupled DDA-SPH method, Proceedings of the symposium on advanced technology of prediction and preventive measures of landslides, 2015.12.
29. GUANGQI CHEN, Modeling of open channel flow for landslide dam formation using smoothed particle hydrodynamics method, Proceedings of the symposium on advanced technology of prediction and preventive measures of landslides, 2015.12.
30. GUANGQI CHEN, Slope unit-based distribution analysis of landslides triggered by the April 20, 2013, Ms 7.0 Lushan earthquake, Arabian Journal of Geosciences, 2015.12.
31. Fan F., GUANGQI CHEN, Numerical study on soil arching effects of stabilizing piles, Memoirs of the Faculty of Engineering, Kyushu University, 2015.07.
32. Yingbin Zhang, Jue Zhang, GUANGQI CHEN, Effects of vertical seismic force on initiation of the Daguangbao landslide induced by the 2008 Wenchuan earthquake, Soil Dynamics and Earthquake Engineering, 10.1016/j.soildyn.2014.06.036, 70, 91-102, 2015.06, This paper analyses the effects of vertical seismic force on initiation mechanism of near-fault large-scale landslides by using the Daguangbao landslide induced by the 2008 Wenchuan earthquake as an example. Field investigations showed that tension failure plays an important role in failure mechanism, and the tension failure is due to the effect of a large vertical seismic motion that occurred in the meizoseismal area during the earthquake. Firstly, two key issues in seismic analysis of near-fault large-scale landslide are proposed: i) how to select and correct the severe near-fault excitations with significant co-seismic displacements and ii) how to consider the effect of the landslide scale on estimation of material strength. Then, in order to investigate the effect of the severe vertical seismic force on the initiation of the huge Daguangbao landslide, five cases, 1) static; 2) pseudo-static only-horizontal; 3) pseudo-static horizontal-and-vertical; 4) dynamic only-horizontal; 5) dynamic horizontal-and-vertical, are performed using the finite difference program FLAC3D. The simulation results are presented in terms of tension failure area, factor of safety, and displacement. The results confirm the significant effects of vertical seismic force on seismic slope failure mechanism as the tension failure areas and the displacements observed in the case of horizontal-and-vertical are larger than those observed in the case of only-horizontal..
33. Jue Zhang, GUANGQI CHEN, Integration of Bivariate Statistics and Analytic Hierarchy Process Methods in Regional Landslides Susceptibility Mapping: A case study of Tsushima Island, Japan, Soil Dynamics and Earthquake Engineering, 10.1016/j.soildyn.2014.06.036, 70, 91-102, 2015.06.
34. Zheng Han, GUANGQI CHEN, Exploring the velocity distribution of debris flows: an iteration algorithm based approach for complex cross-sections, Geomorphology, 241, 72-82, 2015.04.
35. Zheng Han, GUANGQI CHEN, Numerical simulation of debris-flow behavior incorporating a dynamic method for estimating the entrainment, Engineering Geology, 190, 52-64, 2015.03, 土石流の数値シミュレーション手法を開発し、実用的なアプローチの提案により土砂災害防災に寄与できる。.
36. Yingbin Zhang, H. Xing, GUANGQI CHEN, A new movement mechanism of earthquake-induced landslides by considering the trampoline effect of vertical seismic loading, Engineering Geology for Society and Territory, 10.1016/j.soildyn.2014.06.036, 2, 753-758, 2015.02.
37. GUANGQI CHEN, An assessment on the functional effects of the existing preventive structures during landslides, International Journal of Landslide and Environment, 2014.12.
38. Yange LI, GUANGQI CHEN, Zheng Han, A hybrid automatic thresholding approach using panchromatic image for rapid mapping of landslides, GIScience and Remote Sensing, 51, 6, 710-730, 2014.11.
39. Zheng Han, GUANGQI CHEN, Elementary analysis on the bed-sediment entrainment by debris flow and its application using the TopFlowDF model, Geomatics, Natural Hazards and Risk, 10.1080/19475705.2014.966868, 2014.10.
40. T. K. Nian, K. Liu, GUANGQI CHEN, Seismic stability for slopes with multi-row anchors, The Proceedings of the 4th International Conference on Geotechnical Engineering for Disaster Mitigation and Rehabilitation, 543-546, 2014.09, Anchor or pre-stress anchor is one of the most effective countermeasures to stabilize the landslides
and potential unstable slopes in seismically active zone. In this paper, the seismic stability of slope
reinforced with multi-row anchors is analyzed using the pseudo-static approach. Considering the presence of multi-row anchors and vertically seismic acceleration, the upper-bound approach of limit analysis is employed to solve the seismic yield acceleration and the corresponding critical log-spiral failure mechanism. The force provided by anchors is simplified as an axial force, and the seismic load is regarded as pseudo-static body force acting at the center of gravity of the sliding mass. An least upper bound solution of the yield acceleration is obtained based on mathematical optimization method. Furthermore, a series of parametric study is carried out to illustrate the influence of vertical acceleration and anchor position on the stability of slopes..
41. Yingbin Zhang, Qiang Xu, GUANGQI CHEN, Extension of discontinuous deformation analysis and application in cohesive-frictional slope analysis, International Journal of Rock Mechanics and Mining Sciences, 70, 533- 545, 2014.09, This paper extends the discontinuous deformation analysis (DDA) by using an additional evaluation of edge-to-edge contact, with the aim that it can be used to accurately model the failure behaviour of joints dominated by both cohesion and interface friction angle. The original DDA can deal well with the effects of interface friction angle. However, when cohesion exists, DDA results often show an inscrutable behaviour, i.e. a slope may be unstable even if the cohesion is much greater than the theoretical value required for its critical stability. After many detailed investigations and validations, joint contact treatment was found to be the key reason why the original DDA cannot simulate the cohesive material accurately, in which every edge-to-edge contact is treated as two vertex-to-edge contacts that may have different contact states associated with different cohesion treatments. In order to solve this problem, an additional contact type determination process for an edge-to-edge contact was added into the original computer code to avoid the unreasonable situation when two contact states exist in one joint. Several examples were performed to illustrate the accuracy of the modified code and a real landslide case was analysed by using the improved DDA to estimate the shear strength on the interface. Our results show that the improved DDA can simulate the failure of cohesive-frictional material accurately..
42. Zheng Han, GUANGQI CHEN, A new approach for analyzing the velocity distribution of debris flows at typical cross-sections, Natural Hazards, 74, 3, 2053-2070, 2014.06, The asymmetrical distribution of debris-flow velocity in a cross-section has long been observed and is currently regarded as one of the most essential issues in debrisflow research. Due to a lack of quantitative models for the velocity distributions of debris flows, most studies consider only the mean velocity. However, to optimize countermeasure structures, to estimate the erosion rate, or to evaluate the constitutive equations for shear behavior, it is beneficial to know the velocity profile in a cross-section. In this paper, a generalized model of typical channel geometries (e.g., rectangular, trapezoid, or V-shape) is proposed. A description of the velocity distribution that optimizes the Manning–Strickler velocity equation for transverse distribution and Egashira’s velocity equation for vertical distribution is presented; thus, the debris-flow velocity at any point in the cross-section can be calculated and the distribution profile therefore obtained. A well-documented debrisflow reference case and the Jiasikou debris flow in the high-seismic-intensity zone of the Wenchuan earthquake are selected as case studies to demonstrate the model. Analyses of both cases confirm the asymmetrical distribution of debris-flow velocity in cross-section,as originally expected. This shows that the velocity at the top surface in the middle of the channel is much larger than that at each sidewall and than the mean value calculated by former equations. The obtained velocity distribution profile is a better approximation of the observed field profiles.
43. Guruh Samodra, GUANGQI CHEN, Automated landform classification in a rockfall-prone area, Gunung Kelir, Java, European Geosciences Union, 10.5194/esurf-2-339-2014, 2, 239-248, 2014.06, This paper presents an automated landform classification in a rockfall-prone area. Digital terrain models (DTMs) and a geomorphological inventory of rockfall deposits were the basis of landform classification analysis. Several data layers produced solely from DTMs were slope, plan curvature, stream power index, and shape complexity index; whereas layers produced from DTMs and rockfall modeling were velocity and energy. Unsupervised fuzzy k means was applied to classify the generic landforms into seven classes: interfluve, convex creep slope, fall face, transportational middle slope, colluvial foot slope, lower slope and channel bed. We draped the generic landforms over DTMs and derived a power-law statistical relationship between the volume of the rockfall deposits and number of events associated with different landforms. Cumulative probability density was adopted to estimate the probability density of rockfall volume in four generic landforms, i.e., fall face, transportational middle slope, colluvial foot slope and lower slope. It shows negative power laws with exponents 0.58, 0.73, 0.68, and 0.64 for fall face, transportational middle slope, colluvial foot slope and lower slope, respectively. Different values of the scaling exponents in each landform reflect that geomorphometry influences the volume statistics of rockfall. The methodology introduced in this paper has possibility to be used for preliminary rockfall risk analyses; it reveals that the potential high risk is located in the transportational middle slope and colluvial foot slope..
44. T. K. Nian, K. Liu, D. F. Zheng, GUANGQI CHEN, Limit Analysis of Anchored Slopes Subjected to Seismic Loading, Advances in Soil Dynamics and Foundation Engineering GSP 240 © ASCE 2014, 548-553, 2014.05, The seismic stability of an earth slope reinforced with a row of anchors is analyzed within the framework of pseudo-static approach. First, the upper-bound approach of limit analysis combined with strength reduction technique is employed to solve the safety factor and the corresponding critical log-spiral failure mechanism for a given slope. Then, the slope reinforced with a row of anchors is considered, the analytical expressions for calculating the safety factor are derived.The reasonability of solutions is fully verified by comparison with the known solutions from different methods. Further, a pseudo-static seismic load is applied to the anchored slope, and the new analytical formula is also built. Finally, the parametric study is carried out to illustrate the effect.
45. Lu Zheng, GUANGQI CHEN, Yingbin Zhang, The slope modeling method with GIS support for rockfall analysis using 3D DDA, Geomechanics and Geoengineering: An International Journal, 10.1080/17486025.2013.871070, 9, 2, 142-152, 2014.02.
46. Nian Tinkai, Yingbin Zhang, Lu Zheng, GUANGQI CHEN, Failure process simulation of highly jointed rock slope with a fault, Applied Mechanics and Materials, 10.4028/www.scientific.net/AMM.501-504.12, 501, 12-15, 2014.01.
47. Yingbin Zhang, GUANGQI CHEN, Lu Zheng, Effects of near-fault seismic loadings on run-out of large-scale landslide: A case study, Engineering Geology, 166, 216-236, 2013.11, This study presents the run-out analysis of the Daguangbao landslides subjected to near-faultmulti-direction earthquake forces using discontinuous deformation analysis (DDA). The Daguangbao landslide is the largest landslide induced by the 2008 Wenchuan earthquake. In order to investigate the effects of near-fault seismic force on landslide run-out, kinematic behavior of sliding mass is simulated by a dynamic discrete numerical analysis method called DDA. In this simulation, based on the shape of failure surface and the feature of slope geology, thewhole slope is divided into three parts: base block, upper sliding mass, and lower slidingmass. Then two slidingmasses are divided into the smaller discrete deformable blocks based on pre-existing discontinuities. Size effect of the huge landslide is also considered. Baseline corrected real horizontal and vertical ground motions are taken as volume force acting to the base block. The results show that seismic force has a significant influence on the landslide progression, sliding distance, and shape of post-failure. Results of the horizontal-and-vertical situation are in good agreement with those obtained from post-earthquake field investigation, remote sensing image and description fromthe survivors..
48. Jian Wu, GUANGQI CHEN, Lu Zheng, Yingbin Zhang, GIS-based numerical modelling of debris flow motion across three-dimensional terrain, Journal of Mountain Science, 10, 4, 522-531, 2013.10, The objective of this study is to incorporate a numerical model with GIS to simulate the movement, erosion and deposition of debris flow across the three dimensional complex terrain. In light of the importance of erosion and deposition processes during debris flow movement, no entrainment assumption is unreasonable. The numerical model
considering these processes is used for simulating debris flow. Raster grid networks of a digital elevation model in GIS provide a uniform grid system to describe complex topography. As the raster grid can be used as the finite difference mesh, the numerical model is solved numerically using the Leap-frog finite difference method. Finally, the simulation results can be displayed by GIS easily and used to debris flow evaluation. To illustrate this approach, the proposed
methodology is applied to the Yohutagawa debris flow that occurred on 20th October 2010, in Amami-Oshima area, Japan. The simulation results that reproduced the movement, erosion and deposition are in good agreement with the field investigation. The effectiveness of the dam in this real-case is also verified by this approach. Comparison with the results
were simulated by other models, shows that the present coupled model is more rational and effective..
49. Yingbin Zhang, GUANGQI CHEN, Lu Zheng, An analytical method for evaluating the effects of turning corner on 3D slope stability, Computers and Geotechnics, 50, 40-45, 2013.09, The cut complement method (CCM) used to evaluate the effect of a turning corner is discussed in this paper. It is crucial to evaluate the turning corner effect in three-dimensional (3D) slope engineering because this effect may influence the slope stability. CCM determines the criticality of opposing effects by comparing the stabilities of the different components of a turning corner slope (turning, virtual and common components). These effects depend on the slope angle and the cohesion and internal friction angle. CCM determines the critical slope angles for a turning slope with different shear strengths. These results are presented graphically to facilitate the safe and economic design and the reinforcement of corner turning slopes..
50. Yana FAN, GUANGQI CHEN, Susceptibility Zonation of Earthquake induced Landslide-dams at the Catchment of Tongkou River, China, Memoirs of the Faculty of Engineering, Kyushu University, 73, 2, 57-70, 2013.09.
51. GUANGQI CHEN, Zheng Lu, Yingbin Zhang, Practical applications of DDA to disaster prevention, The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11) , 15-28, 2013.08, Some of practical applications of DDA to disaster prevention in Kyushu University are introduced. The first application is to analyze stability of breakwater by considering tsunami induced see page. A local piping mode and global failure mode are clarified by DDA simulations. The second application is to analyze stability and simulate cave-in phenomenon for sand beach. An approach of using DDA to continuous material like sand ground is proposed by generating proper artificial mesh. The bearing capacity and arch function are clarified for the sand ground with a cave. The cave-in phenomenon is reshown by DDA simulations. The third application is to clarify the mechanism of extreme earthquake wave based on so-called trampoline effect and ping-pong model. The extreme waveform with a PGA of more than 4000 gal recorded in Japan is reshown by DDA simulation. These applications will play an important role in disaster prevention in future..
52. Yingbin Zhang, GUANGQI CHEN, Zheng Lu, Detailed investigation of near-fault earthquake loading induced displacement of sliding system by the Discontinuous Deformation Analysis (DDA), The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11) , 153-160, 2013.08, In this paper, a detailed validation of dynamic block is carried out by extended Discontinuous Deformation Analysis (DDA). A rigorous analytical model for a rigid block supported through a frictional contact surface on a horizontal or an inclined plane is proposed in which ground shakings are applied on base block or dynamic block in direction of either horizontally or parallel to the inclined plane, with or without a simultaneous vertical component of motion. Both analytical solution and DDA simulation results for 6 cases (block on an inclined plane, subjected to only-horizontal or horizontal-and-vertical seismic force, and excitation applied on base block or dynamic block) are presented. Two idealized wavelets and one group of accelerograms are used as excitation. Comparisons of the theory solution and DDA results for different cases are carried out. The Results show that DDA can simulate the movement of dynamic block successfully and give accurate results..
53. Zheng Lu, GUANGQI CHEN, Yingbin Zhang, Rock mass stability analysis based on contact mode using DDA, The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11) , 161-167, 2013.08, This paper firstly introduces the process in contact calculation between blocks of Discontinuous Deformation Analysis (DDA) and validates its precision. The contact mode judged after Open-Close iteration is also accurate since the contact force calculation is based on the rigorous equilibrium equations. Therefore, the detachment between two neighboring blocks along joints could be identified quickly and accurately. Based on this, we propose a new approach to search the failure surface in rock mass automatically based on contact mode information. At last, combining with Shear Strength Reduction method (SSR), DDA has been used to analyze the stability of model rock slope using the new proposed failure criterion. Comparing with analytical solution, it is shown that our new approach is applicable and accurate..
54. Yanqiang Wu, GUANGQI CHEN, Zaisen Jiang, The mathematical algorithm of multi-point constraints in the simulations of three-dimensional Numerical Manifold Method, The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11) , 335-340, 2013.08, In this paper, we introduce the parameter adjustment method with condition equations(one surveying adjustment method in geodetic data processing) to three-dimensional Manifold Method through formula derivation, and present the strict-constraint solution and least-squares solution strategies. In least-square solution, we develop the power conception of surveying adjustment and use power ratio to balance the physical and mathematical equations. Then, we use the uniaxial tensile model to verify the validity of above two solution strategies, and analyze their difference. Furthermore, the shearing failure simulation with mathematical constraint is presented. In conclusion, the essential difference of above two strategies is that the strict-constraint strategy can realize strong constraint on some unknowns and have minimum influence on others in the examples of this paper. On the other hand, the least-square strategy influences more than constrained unknowns, and perhaps affects the whole equations. Furthermore, we can control the constraint intensity by adjusting power ratio when using least-square strategy, because the constraint intensity is directly proportional to the power ratio..
55. Zheng Han, GUANGQI CHEN, Yange Li, A numerical simulation of volumetric enlargement for seismic debris flow using integrated DDA and KANAKO 2D, The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11) , 281-287, 2013.08, The assessment of the debris-flow hazard potential has to rely on the debris volume, for now seismic condition and relevant influence is not considered in the current estimation method, which causing the calculating volume far less than reality. Current researches indicate that volumetric enlargement for seismic debris flow mostly due to the debris material accumulation along the flowing path induced by earthquake, however only qualitative or semi-quantitative methods are adopted. In this paper, a method integrating with DDA and dilatant flow model based KANAKO 2D is proposed, in which the process of debris material accumulation is simulated by DDA, the processes of debris material entrainment and debris-flow deposition are simulated by KANAKO 2D. To demonstrate this method, Shekeniluo debris flow gully, which located in the high seismic intensity zone of Wenchuan earthquake in Shimian County, Sichuan Province is selected as a case study. Numerical simulation results show that debris volume and influence area would expand to 3 times, and it is also verified to approximate to the investigation result..
56. Yana FAN, GUANGQI CHEN, Susceptibility analysis of earthquake induced landslide-dam based on GIS, American Rock Mechanics Association , 8 pages, 2013.06.
57. GUANGQI CHEN, Zheng Lu, Yingbin Zhang, Kawakami T., Stability Analysis of Breakwater Under Seepage Flow Using DDA, ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering, Nante, France, 10.1115/OMAE2013-11605, 6, 2013.06.
58. GUANGQI CHEN, Yange Li, Yingbin Zhang, Jian Wu, Earthquake induced disaster chains, 5th Japan-China Geotechnical Symposium, Chengdu, China, 2013.05.
59. GUANGQI CHEN, Lu Zheng, Yingbin Zhang, Jian Wu, Numerical Simulation in Rockfall Analysis: A Close Comparison of 2-D and 3-D DDA, Rock Mechanics and Rock Engineering, 10.1007/s00603-012-0360-9, 46, 3, 527-541, 2013.05, Accurate estimation of rockfall trajectory and motion behaviors is essential for rockfall risk assessment and the design and performance evaluation of preventive structures. Numerical simulation using discontinuous deformation analysis (DDA) is effective and helpful in rockfall analysis. Up to now, there have been many reports on application of two-dimensional (2-D) DDA programs. In this paper, the major advantages of rockfall analysis using 2-D and extensions to three-dimensional (3-D) analysis are presented. A practical 3-D DDA code is demonstrated to be capable of simulating free falling, rolling, sliding, and bouncing with high accuracy. Because rockfall trajectories and motion behaviors can be described as combinations of these four types, this demonstration indicates that the implemented code is capable of providing reliable rockfall analysis. Finally, specific tests are conducted to compare 2-D and 3-D DDA rockfall analysis in
predicting trajectory and dynamic behavior. The results indicate that 3-D DDA simulations are more appropriate for rough tree-laden inclined slopes in providing detailed spatial distribution, whereas 2-D DDA simulations have better efficiency for slopes dominated by valleys and ravines. These results can help in selecting the appropriate DDA simulation for rockfall analysis..
60. Yingbin Zhang, GUANGQI CHEN, Lu Zheng, Yange Li, Xiaoying Zhuang, Effects of geometries on three-dimensional slope stability, Canadian Geotechnical Journal, 10.1139/cgj-2012-0279, 50, 3, 233-249, 2013.03, This paper analyzes the effects of complex geometries on three-dimensional (3D) slope stability using an elastoplastic
finite difference method (FDM) with a strength reduction technique. A series of special 3D slopes with various geometric
configurations, including curving slope surface, turning corners, turning arcs, and turning forms, is presented in terms of factor
of safety, shear slip surface, and deformed mesh. More than 180 cases with various geometries for different slope gradient (90°,
45°, and 26.57°) under different boundary conditions (smooth–smooth, rough–smooth, and rough–rough) are calculated and
discussed in detail. Many interesting results are obtained and some of them appear to be surprising. These results can be used
directly to offer suggestions for landslide hazard preparedness or safe and economical design of infrastructures, e.g., excavations,
embankments, and so on..
61. Yange Li, GUANGQI CHEN, Bo Wang, Lu Zheng, Yingbin Zhang, Chuan Tang, A New Approach for Semi-Automatic Landslide Detection Combined by Remote Sensing and GIS Technology., Natural Hazards, 10.1007/s11069-012-0505-x, 2012.11, 66, 2, 649-669, 2012.11, A multi-temporal landslide inventory is the most basic element to better assess the co-seismic to post long term effects of strong earthquakes on slopes. In addition, quick detection of new slope failures is very helpful for relief and rescue works after each landslide disaster event. However, traditional mapping approaches are affected by the accumulated error by multiple event-based classifications and time consuming. In this paper, a new semi-automatic approach is proposed for rapid mapping of multi-temporal landslides. First, the variance information of each landslides event was assessed by image fusion technique. Second, the fusion image was semi-automatically interpreted. Third, the extracted conjoint landslides were separated by slope units. Chenjiaba area, which located in highest seismic intensity zone of Wenchuan earthquake in Beichuan, China and had a strong rainfall four months later, was selected as a case study to demonstrate the usefulness of this methodology. Accuracy assessment was carried out by comparing those extracted ones with a manually prepared landslide inventory map. Correctly detected were 90.1% and 94.2% for earthquake-induced landslides and rainfall-induced landslides respectively. Results show that this approach is capable of mapping different temporal landslides efficiently and quickly..
62. GUANGQI CHEN, Yange Li, Yingbin Zhang, Jian Wu, The disaster chain of earthquake induced landslides, International Symposium on Earthquake-induced Landslides (IS-Kiryu), Kiryu, Japan, 947-956, 2012.11.
63. Yingbin Zhang, GUANGQI CHEN, Lu Zheng, Yange Li, Numerical analysis of the largest landslide induced by the Wenchuan earthquake, May 12, 2008 using DDA, International Symposium on Earthquake-induced Landslides (IS-Kiryu), Kiryu, Japan, 615-624, 2012.11.
64. Yingbin Zhang, GUANGQI CHEN, Kiyonobu KASAMA, Yange Li, Newmark sliding displacement induced by severe near-fault ground motion, International Joint Symposium on Urban Geotechnics for Sustainable Development, Suwon, Korea, 2012.11.
65. Yanqiang Wu, GUANGQI CHEN, Zaisen Jiang, L. Zhang, X. Liu, The Algorithm of Simplex Integration in Three-Dimension and Its Characteristic Analysis, International Journal of Advancements in Computing Technology, 4, 10, 246-256, 2012.10.
66. GUANGQI CHEN, Rockfall Analysis Using 3D DDA Simulation, The 1st Workshop of ISRM DDA Commission, Seoul, Korea, 2012.10.
67. Li Yange, GUANGQI CHEN, Rainfall and earthquake-induced landslides susceptibility assessment using GIS and Artificial Neural Network, the European Geosciences Union, 10.5194/nhess-12-2719-2012, 12, 2719-2729, 2012.08, A GIS-based method for the assessment of landslide susceptibility in a selected area of Qingchuan County in China is proposed by using the back-propagation Artificial Neural Network model (ANN). Landslide inventory was derived from field investigation and aerial photo interpretation. 473 landslides occurred before the Wenchuan earthquake (which were thought as rainfall-induced landslides (RIL) in this study), and 885 earthquake-induced landslides (EIL) were recorded into the landslide inventory map. To understand the different impacts of rainfall and earthquake on landslide occurrence, we first compared the variations between landslide spatial distribution and conditioning factors. Then, we compared the weight variation of each conditioning factor derived by adjusting ANN structure and factors combination respectively. Last, the weight of each factor derived from the best prediction model was applied to the entire study area to produce landslide susceptibility maps..
68. Li Yange, GUANGQI CHEN, An approach from earthquake-induced landslides identification to numerical simulation of debris flow, Memoirs of the Faculty of Engineering, Kyushu University, 72, 2, 69 - 83, 2012.06.
69. T.-K. Nian, R.-Q. Huang, S.-S. Wan, GUANGQI CHEN, Three-dimensional strength-reduction finite element analysis of slopes: geometric effects, Canadian Geotechnical Journal, 10.1139/T2012-014, 49, 5, 574-588, 2012.05.
70. GUANGQI CHEN, Application of GEOBIA-Multinomial logistic regression for landslide vulnerability assessment in Kayangan Catchment, Indonesia, Proceedings of International Conference on Geographic Object Based Image Analysis, 4. (GEOBIA), 13 -19, 2012.05.
71. Junjie Sun, Lanmin Wang and Guangqi Chen, A probabilistic method to assess the regional susceptibility of landslides induced by earthquake in Kitakyushu City, Japan, Disaster Advances, 4, 1, 7-18, 2011.01.
72. Seismic Bearing Capacity of Artificially Solidified Ground by the Random Field Numerical Limit Analyses.
73. Effects of Water-cement Ratio on the Unconfined Compressive Strength of Cement-mixed and Dehydrated Clays.
74. Strength Property of Large Soil-block by Cement Mixing and Mechanical Dehydration.
75. Guangqi Chen, Lu Zheng, and Kouki Zen, A comparison between DDA and DEM in numerical simulations of earthquake induced landslides, Geomechanics and Geotechnics: From Micro to Macro, 551-557, 2010.10.
76. Residual shear behavior of serpentinite in Shiraishi landslide, Tokushima Prefecture and sliding mechanism.
77. Masaki SANO, Kouki ZEN, Guangqi CHEN and Kiyonobu KASAMA, Effects of Physical Property on the Unconfined Compressive Strength of Cement-Mixed and Dehydrated Clay, The 7th International Symposium on Lowland Technology (ISLT 2010), 70-73, 2010.09.
78. Yuka YAMASHITA, Kouki ZEN, Guangqi CHEN and Kiyonobu KASAMA, Scale-up Test for Producing High-strength Clay by Cement Mixing and Mechanical Dehydration, The 7th International Symposium on Lowland Technology (ISLT 2010), 74-78, 2010.09.
79. K.Yasuhara, H. Komine, S. Murakami, G. Chen , Y. Mitani, D.M. Duc, Effects of climate change on geo-disasters in coastal zones and their adaption, Journal of Geotextiles and Geomembranes, 29, 4, 2010.08.
80. G. Wang, T. Kamai, R. Huang, G. CHEN, F. Du, W. Zhang, A large landslide triggering by the 2008 Wenchuan (M8.0) earthquake: insights of seismic motion, Proceedings of the 11th Congress of the International Association for Engineering Geology and the Environment (IAEG), 757-764, 2010.07.
81. Shaking table test on the dynamic property of solidified ground considering the spatial locality of liquefaction.
82. G. Chen, K. Zen, L. Zheng and Z. Jiang, A new model for long-distance movement of earthquake induced landslide, Proceedings of the 44th U.S. Rock Mechanics and Geomechanics Symposium,  U.S.A, CDROM ARMA 10-297, 2010.06.
83. GUANGQI CHEN , LU ZHENG, KOUKI ZEN and ZAISHENG JIANG, BEHAVIOR OF DDA IN THE SIMULATION OF BLOCK COLLISION FOR EARTHQUAKE INDUCED LANDSLIDE, Recent Developments of Geotechnical Engineering, 572-577, 2010.04.
84. 安原一哉、小峯秀雄、村上 哲、陳 光斉、三谷泰浩、田村 誠, 温暖化による気候変動が地盤災害に及ぼす影響と適応策, 第24回環境工学連合講演会論文集, 85-94, 2010.04.
85. Shaking Table Model Test on Seismic Stability of Caisson Type Quay-Wall in Application of Cement-Mixing Method.
86. K.Yasuhara, H. Komine, S. Murakami, G. Chen & Y. Mitani, Effects of climate change on geo-disasters in coastal zones, Journal of Global Enviroment Engineering, Vol. 15, pp.15-23, 2010.02.
87. Kiyonobu KASAMA, Kouki ZEN and Guangqi CHEN, Shaking Table Test on the Dynamic Earth Pressure against Retaining Structure in Application of Cement-Mixing Method, Proceedings of International Symposium on Ground Improvement Technologies and Case Histories (ISGI09), pp.579-586, 2009.12.
88. Masaki SANO, Kouki ZEN, Guangqi CHEN and Kiyonobu KASAMA, Dehydration and Strength Properties of Cement-Mixed Soils with a Mechanical Dehydration, Proceedings of International Symposium on Ground Improvement Technologies and Case Histories (ISGI09), pp.483-490, 2009.12.
89. Jun KUTSUNA, Kouki ZEN, Guangqi CHEN and Kiyonobu KASAMA, Numerical Limit Analysis on the Seismic Bearing Capacity of Anti-Liquefaction Ground, Proceedings of International Symposium on Ground Improvement Technologies and Case Histories (ISGI09), pp.411-418, 2009.12.
90. Y.L. HOU, G.Q. CHEN and C.H. ZHANG, Extension of Distinct Element Method and Its Application in Fracture Analysis of Quasi-brittle Materials, Proceedings of the 9th International Conference on Analysis of Discontinuous Deformation, Singapore, pp227-236, 2009.11.
91. G. CHEN, J. SUN and K. ZEN, GIS-BASED PROBABILISTIC ANALYSIS OF THE SLOPE SAFETY FACTOR FOR LANDSLIDE HAZARD MAPPING INDUCED BY EARTHQUAKE, Proceedings of International Joint Symposium on Geodisaster prevention and Geoenvironment in Asia, pp76-83, 2009.11.
92. T. NIAN, S. WAN and G.. CHEN, 2D AND 3D SLOPE STABILITY ANALYSIS USING SHEAR STRENGTH REDUCTION FINITE ELEMENT METHOD, Proceedings of International Joint Symposium on Geodisaster prevention and Geoenvironment in Asia, pp71-75, 2009.11.
93. K. YASUHARA, H. KOMINE, S. MURAKAMI, G. CHEN, Y. MITANI, EFFECTS OF CLIMATE CHANGE ON GEO-DISASTERS IN COASTAL ZONES, Proceedings of International Joint Symposium on Geodisaster prevention and Geoenvironment in Asia, pp102-109, 2009.11.
94. Norio KATAOKA, Kouki ZEN, Guangqi CHEN, Kiyonobu KASAMA and Kentaro HAYASHI, Effects of Spatial Variability of Cement-Treated Soil on Liquefaction Potential, Proceedings of International Conference on Performance-Based Design in Earthquake Geotechnical Engineering - from case history to practice -, pp.1249-1554, 2009.06.
95. Kiyonobu KASAMA, Kouki ZEN, Guangqi CHEN, Masakazu KOBAYASHI and Kentaro HAYASHI, Shaking Table Test for Partially Improved Ground Considering the Spatial Locality of Liquefaction, Proceedings of International Conference on Performance-Based Design in Earthquake Geotechnical Engineering - from case history to practice -, pp.1161-1166,, 2009.06.
96. Guangqi CHEN,Kouki ZEN,Zaisen Jiang and Yujian Jiang, Study on Mechanism of Long-distance Movement of Debris from Landslide Induced by Earthquake, Proceedings of International Conference on Earthquake Engineering, pp648-651, 2009.05.
97. K. Kasama, K. Zen and G. Chen, SHAKING TABLE TEST ON THE SEISMIC BEHAVIOR OF CAISSON TYPE QUAYWALL IN APPLICATION OF GROUND SOLIDIFICATION TECHNIQUE, Proceedings of the ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering, p8, CDROM: OMAE2009-79112, 2009.05.
98. Y. Tomi, K. Zen, G. Chen and K. Kasama, EFFECT OF RELATIVE DENSITY ON THE WAVE-INDUCED LIQUEFACTION IN SEABED AROUND A BREAKWATER, Proceedings of the ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering, p7, CDROM: OMAE2009-79601, 2009.05.
99. M. Kobayashi, K. Zen, G. Chen and K. Kasama, SHAKING TABLE TEST ON THE IMPROVEMENT DIMENSION OF PERMEABLE GROUNTING METHOD FOR LIQUEFACTION CONTERMESURE, Proceedings of the ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering, p7, CDROM: OMAE2009-79635, 2009.05.
100. Guangqi CHEN,Kouki ZEN, Study on Mechanism of High Speed & Long-distance Movement of the Debris Induced by Earthquake, Proceedings of the Second China-Japan Science Forum, pp199-200, 2009.03.
101. CHEN Guangqi, PRACTICAL TECHNIQUES FOR RISK ANALYSIS OF EARTHQUAKE-INDUCED LANDSLIDE, Chinese Journal of Rock Mechanics and Engineering, Vol.27, No.12, pp2395-2402, 2008.12.
102. ZHOU Guoyun, CHEN Guangqi, LANDSLIDE RISK PREDICTION BASED ON COUPLING GIS AND SECOND THEORY OF QUANTIFICATION, Chinese Journal of Rock Mechanics and Engineering, Vol.27, No.12, pp2494-2500, 2008.12.
103. CHEN Guangqi,ZEN Kouki,KASUYA Yuki, PRACTICAL RISK ASSESSMENT OF SLOPE DISASTER INDUCED BY EARTHQUAKE, Chinese Journal of Rock Mechanics and Engineering, Vol.27, No.12, pp2488-2493, 2008.12.
104. CHEN Guangqi,ZEN Kouki, Application of Risk Management to Slope Disaster Prevention, Proceedings of the 2nd International Symposium on Climate Change and the Sustainability, pp27-35, 2008.11.
105. MAKIKO MISUMI,KOUKI ZEN,GUANGQI CHEN and KIYONOBU KASAMA, ACCURACY EVALUATION OF SLOPE DISASTER RISK MAP AT KITA-KYUSHU CITY USING GEOGRAPHICAL INFORMATION SYSTEM, Proceedings of the 2nd International Symposium on Climate Change and the Sustainability, pp136-139, 2008.11.
106. Practical Risk Management of Slope Disaster.
107. T.K. Nian, G.Q. CHen, M.T. Luan, Q. Yang, and D.F. Zheng, Limit analysis of the stability of slopes reinforced with piles against landslide in nonhomogeneous and anisotropic soils, Canadian Geotechnical Journal, Vol.45, No.8, pp1092-1103, 2008.08.
108. G. CHEN, K. ZEN & N. Kasuya, RISK MANEGEMENT OF SLOPE DISASTER INDUCED BY EARTHQUAKE, Proceedings of the 13th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, Vol.29,  pp. 927-930, 2007.12.
109. Tomoyuki Shigeoka, Kouki Zen, Guangqi Chen, Kiyonobu Kasama, SEISMIC SETTLEMENT ESTIMATION ON PARTIALLY IMPROVED GROUND USING SHAKING TABLE, NEW FRONTIERS IN CHINESE AND JAPANESE GEOTECHNIQUES, Vol.29,  pp. 521-531, 2007.11.
110. Daisuke Irikado, Kouki Zen, Guangqi Chen, A STUDY ON EVALUATION OF LANDSLIDE RISK INDUCED BY RAINFALL WITH GEOGRAPHICAL INFORMATION SYSTEM, NEW FRONTIERS IN CHINESE AND JAPANESE GEOTECHNIQUES, Vol.29,  pp. 207-212, 2007.11.
111. T.K. Nian, M.T. Luan, Q.Yang & G. Chen, Numerical analysis of stability of slope reinforced with piles subjected to combined load, New Horizons in Earth Reinforcement, Vol.29,  pp. 401-405, 2007.11.
112. Guangqi CHEN, Kouki ZEN and Daisuke IRIKADO, Estimation of economic loss from climate-change-induced natural disasters using GIS Platform, Proceedings of international Symposium on Mitigation & Adaptation of Climate-change-induced Natural Disasters, Vol.29,  pp. 203-212, 2007.09.
113. Guangqi CHEN, A View on Manifold Method Comparing with Finite Element Method, Proceedings of International Symposium on Computational Mechanics, Vol.29,  pp. 1093-1103, 2007.07.
114. Guangqi Chen, Kouki Zen、Hideo Nagase、 Kenichi Sato、Kiyoshi Omine、Taizou Kobayashi、Hidefumi Sato, Investigation and Restoration Countermeasure Work for the Slope Disaster Induced by the 2005 West off Fukuoka Earthquake, SOILS AND FOUNDATIONS, Vol.46, No.6、777−791, 2006.12.
115. Hideo Nagase、Kouki Zen、 Akihiko Hirooka、Noriyuki Yasufuku、Kiyunobu Kasama, Taizou Kobayashi, Guangqi Chen, ZONING FOR LIQUEFACTION AND DAMAGE TO PORT AND HARBOR FACILITIES AND OTHERS DURING THE 2005 FUKUOKA FUKUOKA-KEN SEIHO SEIHO-OKI EARTHQUAKE, SOILS AND FOUNDATIONS, Vol.46, No.6、805−816, 2006.12.
116. Taizou Kobayashi, Kouki Zen, Noriyuki Yasufuku, Hideo Nagase, Guangqi Chen, Kiyonobu Kasama,Akihiko Hirooka, Hiromu Wada, Yuji OnoYama and Hiroshi Uchida, Damage to Residential Retaining Walls at the Genkai-Jima Island Induced by the 2005 Fukuoka-Ken Seiho-Oki Earthquake, SOILS AND FOUNDATIONS, Vol.46, No.6、793-804, 2006.12.
117. Kouki Zen, Guangqi Chen, Kiyonobu Kasama, Kiichiro Kuratomi, Elution Characteristics of Pollutants in Cement-Mixed and Dehydrated Contaminated Sediment, RECENT DEVELOPMENT OF GEOTECHNICAL AND GEO-ENVIRONMENTAL ENGINEERING IN ASIA, 337-342, 2006.11.
118. Takeshi Fujinami, Guangqi Chen, Kouki Zen, Kiyonobu Kasama, An Attempt to Estimate Economic Loss Caused by Typhoon Considering Global Warming, RECENT DEVELOPMENT OF GEOTECHNICAL AND GEO-ENVIRONMENTAL ENGINEERING IN ASIA, 435-440, 2006.11.
119. Kiyonobu Kasama, Kouki Zen, Guangqi Chen, Liquefaction Potential Evaluation for Cement-Treated Sandy Ground, RECENT DEVELOPMENT OF GEOTECHNICAL AND GEO-ENVIRONMENTAL ENGINEERING IN ASIA, 397-402, 2006.11.
120. Hideo Nagase、Kouki Zen、 Akihiko Hirooka、Noriyuki Yasufuku、Kiyunobu Kasama, Taizou Kobayashi, Guangqi Chen, Zoning for liquefaction and structural damage during the 2005 Fukuoka-Ken Seiho-Oki earthquake, RECENT DEVELOPMENT OF GEOTECHNICAL AND GEO-ENVIRONMENTAL ENGINEERING IN ASIA, 40249, 2006.11.
121. Guangqi Chen, Kouki Zen, Shu Moriyama, Risk Analysis of Slope Disasters in a Large Area Using GIS Platform, RECENT DEVELOPMENT OF GEOTECHNICAL AND GEO-ENVIRONMENTAL ENGINEERING IN ASIA, 269-274, 2006.11.
122. Statistical Consideration of the Amount of Disaster Damage by a Typhoon in Kyushu Region.
Presentations
1. Guangqi CHEN, Long ZHANG, Chengwen CAI, Chunmei FAN, Qiang XU, SIMULATION OF EARTHQUAKE GROUND MOTIONS USING DDA, The International Conference for the Decade Memory of the Wenchuan Earthquake with the 4th International Conference on Continental Earthquakes, 2018.05, Earthquake ground motions, such as acceleration time series and peak ground acceleration (PGA), are important and necessary data in earthquake engineering. Although these data can be obtained by seismic observations, they need to be simulated for the regions where records were not available during a past earthquake or for a future potential earthquake. For example, acceleration time series and PGA are necessary in hazard assessment of landslides induced by a potential earthquake on a specific active fault. However, there is no practical simulation system established for this purpose. In this study, we propose two methods. The one is developing a practical system for simulating earthquake ground motions based on the so-called stochastic finite-fault method (SFFM). The other is to estimate PGA in a specific location using 3D-DDA simulation technique based on some extreme ground motions.

Development of a practical system for simulating earthquake ground motions based on SFFM
The key issues in simulating earthquake ground motion are how to consider the source effect, path effect and site effect. Up to now, the effect of asperity, one of the important factors in estimating source parameters, and the effect of volcanic zone on estimating path parameters have not been well investigated. Also, how to estimate the site effect for the location without seismic sensors remains an unsolved problem although site amplification can be estimated based on the seismic observations from both the surface and borehole sensors at the same station. For these reasons, this study aims at developing a practical system for simulating earthquake ground motions based on SFFM, especially, paying attention to volcanic zone and asperity. The system consists of four modules: (1) a module for estimating the site amplification based on a new method proposed even for the location without strong ground-motion observations; (2) a module for estimating shear-wave attenuation based on a new analysis approach which can distinguish volcanic zone from non-volcanic; (3) a module for estimating slip distribution field by considering the characteristics of the asperity on a fault; (4) the SFFM module for calculating ground motions. Also, the system is applied to simulate the PGA distribution for landslide hazard assessment in Aso-bridge region, Kumamoto, Japan. It is shown that the assessment accuracy is improved using the simulated PGA than the conventional assumed PGA based on landslides induced by the 2016 Kumamoto earthquake.

Estimation of PGA using 3D-DDA numerical simulation based on extreme ground motion phenomenon
The 2016 Kumamoto Earthquake induced a number of landslides and one of the largest scale landslides is located at Aso bridge area on the Futagawa Fault. In order to study the landslide, it is necessary to know the ground motion or PGA (Peak Ground Acceleration) there. Although there are four seismic stations around the area, no records can be directly used because of geotechnical side effect which is expected very large due to near the seismic fault. Meanwhile, we noticed another extreme ground motion phenomenon that several vehicles were toppled near the landslide. Therefore, this study aims at inversing the PGA around the landslide by simulating the phenomenon of toppled vehicles using 3D DDA (Discontinuous Deformation Analysis). At first, the car model for DDA simulation is made. The mechanism of vehicle toppled phenomenon is clarified by investigating 1) the effect of the seismic frequency; 2) the effect of the parameters of a car such as weight distribution, gravity center, tire’s Young’s Modulus, parking direction. And then, the PGA for Aso bridge area is estimated based on the above discussions by the use of the seismic waves recorded at the station KMMH16 that is also close to the Futagawa Fault..
2. Guangqi CHEN, Long ZHANG, Chengwen CAI, Chunmei FAN, Qiang XU , SIMULATION OF EARTHQUAKE GROUND MOTIONS, The 5th International Symposium on Mega Earthquake Induced Geo-disasters and Long Term Effects, 2018.05, Earthquake ground motions, such as acceleration time series and peak ground acceleration (PGA), are important and necessary data in earthquake engineering. Although these data can be obtained by seismic observations, they need to be simulated for the regions where records were not available during a past earthquake or for a future potential earthquake. For example, acceleration time series and PGA are necessary in hazard assessment of landslides induced by a potential earthquake on a specific active fault. However, there is no practical simulation system established for this purpose. In this study, we propose two methods. The one is developing a practical system for simulating earthquake ground motions based on the so-called stochastic finite-fault method (SFFM). The other is to estimate PGA in a specific location using 3D-DDA simulation technique based on some extreme ground motions.

1. Development of a practical system for simulating earthquake ground motions based on SFFM
The key issues in simulating earthquake ground motion are how to consider the source effect, path effect and site effect. Up to now, the effect of asperity, one of the important factors in estimating source parameters, and the effect of volcanic zone on estimating path parameters have not been well investigated. Also, how to estimate the site effect for the location without seismic sensors remains an unsolved problem although site amplification can be estimated based on the seismic observations from both the surface and borehole sensors at the same station. For these reasons, this study aims at developing a practical system for simulating earthquake ground motions based on SFFM, especially, paying attention to volcanic zone and asperity. The system consists of four modules: (1) a module for estimating the site amplification based on a new method proposed even for the location without strong ground-motion observations; (2) a module for estimating shear-wave attenuation based on a new analysis approach which can distinguish volcanic zone from non-volcanic; (3) a module for estimating slip distribution field by considering the characteristics of the asperity on a fault; (4) the SFFM module for calculating ground motions. Also, the system is applied to simulate the PGA distribution for landslide hazard assessment in Aso-bridge region, Kumamoto, Japan. It is shown that the assessment accuracy is improved using the simulated PGA than the conventional assumed PGA based on landslides induced by the 2016 Kumamoto earthquake. The following conclusions have been obtained
① The site amplification of 53 KiK-net stations in the Kyushu region are calculated. Compared with the S/B method, the H/V method is not suitable to be used in Kyushu Island due to the significant amplification in the vertical component.
② A method for estimating the site amplification in the region without SGM stations is developed and made as a module.
③ A method for estimating the S-wave attenuation considering the volcanic effect is proposed and made as a module.
④ The accuracy of the PGA estimated based on the slip distribution fields inversed from different kinds of data is discussed. A combination of the three results is proposed to improve the accuracy of simulated PGA.
⑤ An approach for generating the slip distribution field for a potential earthquake with an expected magnitude on a specific fault is proposed and made as a module.
⑥ A practical system for simulating earthquake ground motions paying attention to volcanic zone and asperity on a fault is developed and successfully applied to the landslide hazard assessment.

2. Estimation of PGA using 3D-DDA simulation based on extreme ground motion phenomenon
The 2016 Kumamoto Earthquake induced a number of landslides and one of the largest scale landslides is located at Aso bridge area on the Futagawa Fault. In order to study the landslide, it is necessary to know the ground motion or PGA (Peak Ground Acceleration) there. Although there are four seismic stations around the area, no records can be directly used because of geotechnical side effect which is expected very large due to near the seismic fault. Meanwhile, we noticed another extreme ground motion phenomenon that several vehicles were toppled near the landslide. Therefore, this study aims at inversing the PGA around the landslide by simulating the phenomenon of toppled vehicles using 3D DDA (Discontinuous Deformation Analysis). At first, the car model for DDA simulation is made. The mechanism of vehicle toppled phenomenon is clarified by investigating 1) the effect of the seismic frequency; 2) the effect of the parameters of a car such as weight distribution, gravity center, tire’s Young’s Modulus, parking direction. And then, the PGA for Aso bridge area is estimated based on the above discussions by the use of the seismic waves recorded at the station KMMH16 that is also close to the Futagawa Fault. The following conclusions have been obtained in this study.
① The extreme ground motion of car toppled phenomenon has been successfully simulated by using 3D-DDA.
② The mechanism of toppled car has been clarified. It has been found that two kinds of factors may contribute to the phenomenon. One factor is the vehicle condition such as the weight distribution, the gravity center and the Young’s modulus. The other is the external factor including the seismic frequency, parking directions and the vertical component of ground motions.
③ The PGA for the study area has been estimated as about 16.3 m/s2 from the DDA simulation of the car toppled phenomenon based on the seismic waves recorded at the station KMMH16. It has been found the PGA is 1.41 times of the records at the near station. Therefore, the amplified seismic waves recorded at the station KMMH16 can be used for the study on the large scale landslide analysis in Aso bridge area in the future..
3. Guangqi Chen, Wei Wang, Hong Zhang, Yingbin Zhang, Numerical simulation of landslide-dam using a 3D DDA and SPH coupled solid-fluid simulation technique, THE SEVENTH CHINA-JAPAN GEOTECHNICAL SYMPOSIUM, 2018.03.
4. Guangqi Chen, Some common problems and solutions in practical DDA application, 13th International Conference on Analysis of Discontinuous Deformation, 2017.12, It is offen heard that DDA (Discontinuous Deformation Analysis) is an excellent numerical method but using it requres advanced technical capabilities and a good experience. This is because a lot of things have not been discussed in DDA theroy book and there is no commerical software including all the improvments and extensions made by a lot of researchers. In this study, some key issues in 2D DDA, such as multi joint sets, panelty spring, dynamic and static DDA, maximum allowed displacement, are discussed. The common problems are analyzed and the solutions are proposed. Also, one of the problems in application of 3D DDA-SPH to landslide-dam formation and failure is discussed and the solution is proposed.
(1) The modification of both the model and DDA program is required for a DDA model with different joint sets. Otherwise, the correct analysis cannot be made. (2) No penetration should be stated as small penetration. A proper spring stiffness is necessary and it is related to loadings on the contacted blocks but not related to E. Using a large spring stiffness can result in a large random force, which makes instable, due to the error of calculated penetration. (3) There would be no need to distinct dynamic and static analysis if a proper initial processing is done. (4) The parameter Pmad is one very important parameters and the improper value can lead some strange phenomena and a method is proposed to clarify it. (5) A natural river can be modelled in 3D DDA-SPH..
5. Guangqi Chen, DEVELOPMENT OF A 3D COUPLED SOLID-FLUID SIMULATION TECHNIQUE USING DDA AND SPH AND APPLICATION TO LANDSLIDE INDUCED CHAIN DISASTERS, 2017 Forum on Simulation and Analysis Techniques for Hazard Mitigation and Prevention of Civil and Hydraulic Systems, 2017.12, 1. Some applications of 2D DDA to landslide disaster prevention.
2. Landslide induced chain disasters.
3. Development of a program for simulating debris flow.
4. Devlopment of a coupled solid-fluid program using 3D DDA and SPH.
5. Application of the 3D DDA-SPH to landslide-dam simulation.
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6. GUANGQI CHEN, An approach of landslide risk assessment in Japan by considering global climate change
, THE 15TH INTERNATIONAL SYMPOSIUM ON GEO-DISASTER REDUCTION , 2017.08, 1.The approach of landslide risk mapping for the project
①Develop a tool for landslide risk mapping
 ②Assess landslide risk over the whole Japanese territory
 ③Evaluate the risk increase with extreme climate change
2.Improvements on the landslide risk mapping approach
 ①A new model for rainfall infiltration
 ②Development of a real time hazard mapping method
 ③Develop a GIS-based 2d & 3d stability analysis based on circular and ellipse slip surface
Further studies from the project
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7. GUANGQI CHEN, Tsukasa KAWAKAMI, Yingbin ZHANG, Mechanism analysis of earthquake induced extreme motions: Clarifying extreme acceleration
, The 51th US Rock Mechanics/Geomechanics Symposium , 2017.06, Earthquake induced extreme motions are classified as the extreme large acceleration, the extreme large velocity and the extreme large displacement. In this paper, a sudden braking model is proposed for the mechanism of the extreme large acceleration, i.e. the extreme large acceleration can easily occur when a moving body is suddenly braked. The model is verified by theoretical analysis, laboratory experiments and numerical simulation using DDA. It is successful to reproduce the unprecedented vertical surface acceleration of nearly four times gravity, recorded at the West Ichinoseki station during the 14 June 2008 Iwate-Miyagi earthquake (Ms6.9) in Japan, by DDA simulation. .
8. Yingbin ZHANG, GUANGQI CHEN, Shaking table test for estimating the effects of seismic loading on the mobility of rockfall, The 51th US Rock Mechanics/Geomechanics Symposium , 2017.06.
9. GUANGQI CHEN, Mechanism clarification of earthquake induced extreme motions, International Workshop on the 2016 Kumamoto Earthquake (IWKE), 2017.03.
10. GUANGQI CHEN, Mechanism clarification of earthquake induced extreme motions
, International Workshop on the 2016 Kumamoto Earthquake , 2017.03.
11. GUANGQI CHEN, Next generation numerical simulation technique for discontinuous rock mechanics, The Second International Academic Conference on Discontinuous Rock Mechanics, 2016.11.
12. GUANGQI CHEN, Development of a solid-fluid simulation technique for analysis of landslide induced chain disasters, The 14th International Symposium on Geo-disaster Reduction, 2016.10, Landslide can create a landslide dam when its debris fill into and stop a river; while the dam is being filled, the surrounding water level rises and causes back-flooding (upstream flooding). Because of its rather loose nature and absence of controlled spillway, a landslide dam can easily collapse catastrophically and lead to debris flow or downstream flooding. Also, the landslide debris can be removed into a valley or a ravine by excessive precipitation to form debris flow. These secondary disasters occur as a disaster chain, i.e. “disaster triggering disaster”. Therefore, it is very important and necessary to cut the disaster chain in an early stage. This paper majorly focuses on the study of landslide dam.
Many studies have been made to analyze the formation and failure of a landslide dam. Most of them majorly use statistical methods or empirical formulas to assess the possibility of formation and failure based on geomorphological parameters of the dam and river. However, the formation of a landslide dam is not only related to geomorphological parameters but also to kinematic coupling between the river flow and the movement of the landslide mass. Particularly, the formation and failure of landslide dam always involves complicated solid-fluid interaction. Therefore, the kinematic characteristics and interaction process of river flow and landslide mass should be well analyzed. With the development of computer and computation sciences, various numerical methods have been developed and shown their powerful capabilities in simulating the solid and fluid dynamics. Among them, Discontinuous Deformation Analysis (DDA) shows great advantages in simulating rigid body movements from theory to practice, and Smoothed Particle Hydrodynamics (SPH) is very capable to model the free surface flow. Although there have been some studies on the coupling of DDA with SPH, the practical simulation technique for landslide dam formation and failure is still unavailable because of the following three unsolved key issues: (1) how to produce a river flow with steady motion under the SPH framework; (2) how to simulate a large-scale landslide movement over a complicated 3D topography; (3) how to accomplish the simulation involving large-scale, complicated solid and fluid phases and their interaction in practical landslide dam formation and failure.
In this study, a practical 3D coupled solid-fluid simulation technique is developed by using DDA and SPH to analyze the formation and failure characteristics of the landslide dam. At first, an Open Channel Model with Steady Flow (OCMSF) and a Particle Recycling Method (PRM) are proposed to solve the first issue. Then, an Ordered Blocky Method (OBM) is developed to solve the second issue. Also, the coupled DDA-SPH method is validated by a laboratory experiment, and a series of typical examples are performed to analyze the formation and failure characteristics of the landslide dam. Finally, a Three-stage Simulation Strategy (TSSS) is proposed to solve the third issue. The developed simulation technique is successfully applied to simulate a practical landslide dam and its effectiveness and practicality are validated..
13. GUANGQI CHEN, Stability analysis of toppling slope using the extended NMM, The 50th US Rock Mechanics/Geomechanics Symposium , 2016.06, The original numerical manifold method (NMM) is extended for stability analysis of a toppling slope with complex sliding surface and cohesion and tensile strengths existing in discontinuities. The extended NMM is shown effective by reproducing a centrifuge test. With NMM simulation, the commonly used Goodman and Bray’s analytical method is shown adaptable to a toppling slope model with a simple sliding surface without cohesion and tensile strengths in the discontinuities. It is shown that the deformation of the sliding body has no significant effect on the result. The relationship between dip angle and critical friction angle is investigated. A real toppling slope is simulated and the necessary cohesion and friction angle are verified.
14. Wang W., GUANGQI CHEN, Modeling of open channel flow for landslide dam formation using smoothed particle hydrodynamics method, The symposium on advanced technology of prediction and preventive measures of landslides, Fukuoka 2015 , 2015.12.
15. Jing P., GUANGQI CHEN, Simulation of dynamic block displacement using 3D-DDA method, The symposium on advanced technology of prediction and preventive measures of landslides, Fukuoka 2015, 2015.12.
16. Zhou S., GUANGQI CHEN, Integration of Bivariate Statistics and Analytic Hierarchy Process Methods in Regional Landslides Susceptibility Mapping: A case study of Tsushima Island, The symposium on advanced technology of prediction and preventive measures of landslides, Fukuoka 2015, 2015.12.
17. Han Z., GUANGQI CHEN, A method for estimating the bed-sediment entrainment in debris flow, THE 15TH ASIAN REGIONAL CONFERENCE ON SOIL MECHANICS AND GEOTECHNICAL ENGINEERING, 2015.11.
18. Wang W., GUANGQI CHEN, Modeling of landslide generated waves in Three Gorges Reservoir, China using SPH method , THE 15TH ASIAN REGIONAL CONFERENCE ON SOIL MECHANICS AND GEOTECHNICAL ENGINEERING, 2015.11.
19. GUANGQI CHEN, Hazard mapping of landslide-dam induced by earthquake , THE 15TH ASIAN REGIONAL CONFERENCE ON SOIL MECHANICS AND GEOTECHNICAL ENGINEERING, 2015.11.
20. Jing P., GUANGQI CHEN, Simulation of the bolt mechanism using three dimensional discontinuous deformation analysis
, 12th International Conferences on Analysis of Discontinuous Deformation, 2015.10.
21. Wang W., GUANGQI CHEN, Numerical modeling of landslide generated impulsive waves using coupled DDA-SPH method, 12th International Conferences on Analysis of Discontinuous Deformation, 2015.10.
22. GUANGQI CHEN, Development of a practical solid-fluid coupling simulation technique using DDA and SPH, 12th International Conferences on Analysis of Discontinuous Deformation, 2015.10.
23. GUANGQI CHEN, Development & application of DDA & MM, DDA Workshop in Asian Rock Mechanics Symposium , 2014.10.
24. Jing P., GUANGQI CHEN, Application of 3D-DDA to simulate the kinematic behavior of rock slope, DDA Workshop in Asian Rock Mechanics Symposium, 2014.10.
25. FAN F., GUANGQI CHEN, Mechanism analysis of toppling failure using numerical manifold method, DDA Workshop in Asian Rock Mechanics Symposium, 2014.10.
26. Han Z., GUANGQI CHEN, Development of Cellular Automaton Model for Simulating the Propagation Extent of Debris Flow at Alluvial Fan: A Case Study of Yohutagawa, Japan, The TC105 ISSMGE International Symposium on Geomechanics from Micro to Macro, 2014.09.
27. Zhang H., GUANGQI CHEN, A new discontinuous model for three dimensional analysis of fluid-solid interaction behavior, The TC105 ISSMGE International Symposium on Geomechanics from Micro to Macro, 2014.09.
28. Kawakami T., GUANGQI CHEN, Vertiffivation of earthquake trampoline effect on ground movement by shaking table test, 大韓土木学会―日本土木学会―台湾公共工程学会ジョイントセミナー2014, 2014.08.
29. GUANGQI CHEN, Hazard mapping for earthquake induced geo-disaster chain, The Sixth Japan - Taiwan Joint Workshop on Geotechnical Hazards from Large Earthquakes and Heavy Rainfall , 2014.07.
30. Zhou S., GUANGQI CHEN, GIS-based support vector machine modeling of landslides triggered by April 20, 2013 Lushun earthquake, Sichuan, China, The 6th Japan-Taiwan Workshop on Geotechnical Hazards from Large Earthquakes and Heavy Rainfall, 2014.07.
31. Jing P., GUANGQI CHEN, Application of three-dimensional deformation analysis to simulate characteristics of planar translational slope failure, The 6th Japan-Taiwan Workshop on Geotechnical Hazards from Large Earthquakes and Heavy Rainfall, 2014.07.
32. Han Z., GUANGQI CHEN, Numerical Simulation of Post-entrainment Debris Flow at Alluvial Fan Using FLO-2D Model, The 6th Japan-Taiwan Workshop on Geotechnical Hazards from Large Earthquakes and Heavy Rainfall, 2014.07.
33. GUANGQI CHEN, Risk Assessment on earthquake induced landslide chain disasters , The 2nd IACGE International Conference on Geotechnical and Earthquake Engineering, 2013.10.
34. Hong Zhang, GUANGQI CHEN, Y. Zhang, L. Zheng, Mechanism of shallow rainfall-induced landslide and simulation of initiation with DDA, The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11), 2013.08, [URL].
35. Fusong FAN, GUANGQI CHEN, Y. Zhang, L. Zheng, Study on soil arching effects of stabilizing piles using numerical methods, The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11), 2013.08, [URL].
36. Guruh Samodra, GUANGQI CHEN, Y. Zhang, L. Zheng, Combining GIS and DDA for preliminary rockfall risk assessment in Gunung Kelir area Yogyakarta Indonesia, The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11), 2013.08, [URL].
37. T. Kawakami, GUANGQI CHEN, Y. Zhang, L. Zheng, Stability analysis of breakwater in terms of seepage flow using DDA, The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11), 2013.08, [URL].
38. GUANGQI CHEN, Y. Zhang, L. Zheng, Practical applications of DDA to disaster prevention, The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11), 2013.08, [URL], Some of practical applications of DDA to disaster prevention in Kyushu University are introduced. The first application is to analyze stability of breakwater by considering tsunami induced seepage. A local piping mode and global failure mode are clarified by DDA simulations. The second application is to analyze stability and simulate cave-in phenomenon for sand beach. An approach of using DDA to continuous material like sand ground is proposed by generating proper artificial mesh. The bearing capacity and arch function are clarified for the sand ground with a cave. The cave-in phenomenon is reshown by DDA simulations. The third application is to clarify the mechanism of extreme earthquake wave based on so-called trampoline effect and ping-pong model. The extreme waveform with a PGA of more than 4000 gal recorded in Japan is reshown by DDA simulation. These applications will play an important role in disaster prevention in future. .
39. L. Zheng, GUANGQI CHEN, Y. Zhang, Rock mass stability analysis based on contact mode using DDA, The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11), 2013.08, [URL].
40. Y. Zhang, GUANGQI CHEN, L. Zheng, Detailed investigation of near-fault earthquake loading induced displacement of sliding system by the Discontinuous Deformation Analysis (DDA), The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11), 2013.08, [URL].
41. Zheng Han, GUANGQI CHEN, Yange Li, A numerical simulation of volumetric enlargement for seismic debris flow using integrated DDA and KANAKO 2D, The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11), 2013.08, [URL].
42. Yanqiang Wu, GUANGQI CHEN, Zaisen Jiang, The mathematical algorithm of multi-point constraints in the simulations of three-dimensional Numerical Manifold Method, The 11th International Conference on Analysis of Discontinuous Deformation (ICADD11), 2013.08, [URL].
43. Yana FAN, GUANGQI CHEN, Susceptibility analysis of earthquake induced landslide-dam based on GIS, the 47th U.S. Rock Mechanics and Geomechanics Symposium, 2013.06.
44. GUANGQI CHEN, Y. Zhang, L. Zheng, Stability Analysis of Breakwater Under Seepage Flow Using DDA, ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering, Nante, France, 2013.06.
45. GUANGQI CHEN, Earthquake induced a chain of disasters, ATC3 TAIWAN-JAPAN COLLABORATIVE RESEARCH WORKSHOP ON NATURAL DISASTERS, 2011.09.
46. GUANGQI CHEN, Application of DDA simulations to landslide analysis, 2011 International Workshop on Geotechnical Engineering , 2011.07.
Membership in Academic Society
  • the American Rock Mechanics Association
  • Japan Society for Natural Disaster Science」 Vol.29, No.1
Educational
Educational Activities
I am supervisor of Ph.D. candidates. My major lectures are "Numerical Methods" to undergraduate students and "Risk Management for Natural Disasters" to graduate students.
Other Educational Activities
  • 2018.03.
  • 2017.05.
  • 2017.05.
  • 2017.04, Severial my students are awarded prizes (PhD student: 1, Master student: 1, Undergraduate student:1 ).
  • 2015.03.
  • 2014.03, Severial my students are awarded prizes (PhD student: 1, Master student: 1 )
    .
  • 2014.02, I engaged in The 21st Century Program by evaluating graduation thesis. And I gave guidance and advices to a lot of students by asking questions and giving comments in the oral examination..
  • 2013.12, I engaged in G30 International Undergraduate Course and made great effort in the related activities such as promotion and entrance examination in a lot of schools in China and Hong Kong..
  • 2014.05, I made more effort to educate PhD students. Three students among 8 doctoral candidates got their doctoral degree successfully in 2013..
  • 2013.03, Severial my students are awarded prizes (PhD student: 1, Master student: 3 and undergraduate student:1)
    .
  • 2013.02, I engaged in The 21st Century Program by evaluating graduation thesis for two students. And I gave guidance and advices to a lot of students by asking questions and giving comments in the oral examination..
  • 2013.03, I contribute to the new curriculum for arts and science by taking parting in the 3 working groups .
  • 2013.01, I engaged in G30 International Undergraduate Course and made great effort in the related activities such as promotion and entrance examination in a lot of schools in China and UK..
  • 2012.09, I made more effort to educate PhD students. Four students among 9 doctoral candidates got their doctoral degree successfully in 2012..
  • 2010.11.
  • 2011.02.
  • 2011.02.
  • 2010.04.
  • 2010.02.
  • 2009.04.
  • 2008.11.
  • 2008.04.
  • 2007.05.