Simulating the failure process of the Xinmo landslide using discontinuous deformation analysis

Chen, Kun-Ting; Wu, Jian Hong

doi:10.1016/j.enggeo.2018.04.002

Cited by 122 publications

(44 citation statements)

References 20 publications

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“…Grain deformation and crack mechanisms in sinkholes are crucial. Numerical analysis for predicting future sinkhole events in urban areas may be recommended using grain-based models, such as Particle Flow Code (PFC) and related numerical techniques [23][24][25].…”

Section: Role Of Clay Content In Sinkhole Riskmentioning

confidence: 99%

The Influence of Clay Content on Cave-ins in Tank Model Tests and Monitoring Indicators of Sinkhole Formation

Jeong¹,

Yum²,

Ryu³

et al. 2019

Applied Sciences

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Urban cave-ins may result from a sudden change in local hydrological, hydrogeological and anthropogenic conditions. Monitoring and predicting urban sinkholes is not straightforward, and solving the problem of urban cave-ins involves the incorporation of the fields of geodetics, geophysics and geochemistry. This paper examines the causes and consequences of sinkholes in sand-rich materials by using a small tank model apparatus. Tank model tests were conducted to simulate sinkhole formation, to gain a better understanding of the influencing factors of cavity formation, expansion and upward migration with different cavity water levels. Two commercial materials were used: Jumunjin sand and kaolinite clay. Materials with different grain-size distributions, i.e., sand (100% Jumunjin sand) and sand-clay mixtures (95% sand and 5% kaolinite clay), were considered to examine the roles of clay content in sinkhole risk. The test results show that the sand-rich materials exhibited a typical punching type of sinkhole subsidence and failure, and were very sensitive to changes in groundwater level, regardless of the grain-size distribution. The higher the groundwater level is, the higher the sinkhole risk is in terms of the speed of migration of the underground cavity fluids, cavity size and ground loosening. Therefore, sinkholes in urban areas covered with sand-rich materials are vulnerable to groundwater withdrawal. However, compared with pure sand, materials with small clay contents can reduce the time until collapse and the size of a sinkhole. Variations in pore water pressure may be used as a sinkhole indicator in areas where the ground deformation caused by groundwater depletion is considerable.

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Section: Role Of Clay Content In Sinkhole Riskmentioning

confidence: 99%

The Influence of Clay Content on Cave-ins in Tank Model Tests and Monitoring Indicators of Sinkhole Formation

Jeong¹,

Yum²,

Ryu³

et al. 2019

Applied Sciences

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show abstract

“…Compared with the DEM, the DDA has more rigorous mathematical theory and higher computational accuracy . Although the DDA is relatively young, it has been widely applied in various aspects of geotechnical engineering, such as tunnel engineering, rock hydraulic fracturing, rock burst analysis, and landslide . However, the computational efficiency of the DDA is much lower than that in the DEM, although there has been great progress within DDA researches over the past three decades .…”

Section: Introductionmentioning

confidence: 99%

Highly efficient iterative methods for solving linear equations of three‐dimensional sphere discontinuous deformation analysis

Huang

et al. 2020

Num Anal Meth Geomechanics

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The efficiency of solving equations plays an important role in implicit-scheme discontinuous deformation analysis (DDA). A systematic investigation of six iterative methods, namely, symmetric successive over relaxation (SSOR), Jacobi (J), conjugate gradient (CG), and three preconditioned CG methods (ie, J-PCG, block J-PCG [BJ-PCG], and SSOR-PCG), for solving equations in threedimensional sphere DDA (SDDA) is conducted in this paper. Firstly, simultaneous equations of the SDDA and iterative formats of the six solvers are presented. Secondly, serial and OpenMP-based parallel computing numerical tests are done on a 16-core PC, the result of which shows that (a) for serial computing, the efficiency of the solvers is in this order: SSOR-PCG > BJ-PCG > J-PCG > SSOR>J > CG, while for parallel computing, BJ-PCG is the best solver; and (b) CG is not only the most sensitive to the ill-condition of the equations but also the most time consuming under both serial and parallel computing. Thirdly, to estimate the effects of equation solvers acting on SDDA computations, an application example with 10 000 spheres and 200 000 calculation steps is simulated on this 16-core PC using serial and parallel computing. The result shows that SSOR-PCG is about six times faster than CG for serial computing, while BJ-PCG is about four times faster than CG for parallel computing. On the other hand, the whole computation time using BJ-PCG for parallel computing is 3.37 hours (ie, 0.061 s per step), which is about 36 times faster than CG for serial computing. Finally, some suggestions are given based on this investigation result. K E Y W O R D Shigh efficiency, iterative method, linear equation solver, three-dimensional discontinuous deformation analysis, sphere DDA | INTRODUCTIONBoth the discontinuous deformation analysis (DDA) method 1 and discrete element method (DEM) 2 are proposed to simulate the mechanical behaviors of discrete block systems. The DDA and DEM have extensive prospects in engineering application since they can automatically trace and simulate block rotation, fracture opening, and complete detachments, which are often included in real jointed rock masses failure process. 3,4 Compared with the DEM, the DDA has more rigorous mathematical theory and higher computational accuracy. 5,6 Although the DDA is relatively young, it has been widely applied in various aspects of geotechnical engineering, such as tunnel engineering, 7 rock hydraulic fracturing, 8,9 rock burst analysis, 10 and landslide. 11 However, the computational efficiency of the DDA is much lower than that in the DEM, although there has been great progress within DDA researches over the past three decades. 12 The main reason for this is that the DEM uses an explicit time integration scheme and the second law of Newton is used to calculate the displacement of each block independently, while the DDA often uses an implicit solution method in which simultaneous equilibrium equations are assembled by applying the minimum potential energy principle and solved in each calcul...

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“…DDA is generally recognized as a useful tool for solving various kinds of discontinuities in geotechnical problems. [13][14][15][16][17][18][19][20][21][22][23][24] Its basic unknown variables are independent of geometry appearance of individual body, and the basis for describing the motion of these bodies is the principle of minimum potential energy. Over the past several decades, a great number of progresses have been made on DDA.…”

Section: Introductionmentioning

confidence: 99%

Variational inequality‐based particle discontinuous deformation analysis

Fan

Wang

Zheng

2019

Num Anal Meth Geomechanics

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Summary Orienting the circular and rigid particle medium, the variational inequality‐based discontinuous deformation analysis (DDA) is established. In the proposed DDA, the global stiffness matrix, the penalty parameters, and the open‐close iteration are successfully avoided. The contact constraint is transferred into the problem of variational or quasi‐variational inequalities. And explicit variational expression on the contact force is firstly established. To speed up the rate of solving contact force, on the basis of the two‐stage prediction‐correction method, we design a compatibility iteration algorithm (PPC‐CI). The C++ code is developed in multicore environment through the open multi‐processing (OpenMP) in order to take advantage of the parallelizable features of the new DDA. Numerical tests suggest that the presented DDA is effective and promising.

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Simulating the failure process of the Xinmo landslide using discontinuous deformation analysis

Cited by 122 publications

References 20 publications

The Influence of Clay Content on Cave-ins in Tank Model Tests and Monitoring Indicators of Sinkhole Formation

The Influence of Clay Content on Cave-ins in Tank Model Tests and Monitoring Indicators of Sinkhole Formation

Highly efficient iterative methods for solving linear equations of three‐dimensional sphere discontinuous deformation analysis

Variational inequality‐based particle discontinuous deformation analysis

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