scholarly journals Study on the Dynamic Response of Landslide Subjected to Earthquake by the Improved DDA Method

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xiu-Li Zhang ◽  
Bi-Ting Xie ◽  
Hao Wang ◽  
Yu-Yong Jiao
Keyword(s):  
Dynamic Response ◽  
Strong Earthquake ◽  
Jointed Rock ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Ancient Landslide ◽  
Alternative Approach ◽  
Discontinuous Deformation ◽  
Viscous Boundary ◽  
Dda Method

Majiagou landslide, a major ancient landslide in Three Gorges Reservoir region, is located in the high earthquake area of southwest China. The 2013 Badong earthquake caused an obvious deformation of landslide monitored by the sliding inclinometer. A strong earthquake may induce the reactivation of ancient landslide. So, it is necessary to research the seismic dynamic response of Majiagou landslide. For this purpose, discontinuous deformation analysis (DDA), improved by introducing the artificial joint and viscous boundary, is applied in this study. The displacements at monitoring points caused by Badong earthquake are calculated and compared with the field data, verifying the numerical method and model. Further, a strong earthquake with the peak acceleration of 1 g is assumed to act on the landside, the initiation and evolution process of landslide is simulated, and the movement features of landslide are discussed. The dynamic failure of landslide and the local amplification of seismic wave can be embodied, indicating that the improved DDA provides an alternative approach for analyzing the seismic dynamic response of jointed rock.

scholarly journals Numerical modeling of complex hydraulic fracture networks based on the discontinuous deformation analysis (DDA) method

2021 ◽  
pp. 014459872098153
Author(s):  
Yanzhi Hu ◽  
Xiao Li ◽  
Zhaobin Zhang ◽  
Jianming He ◽  
Guanfang Li
Keyword(s):  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Fracture Network ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Fracture Networks ◽  
Proposed Model ◽  
Discontinuous Deformation ◽  
Shale Reservoirs ◽  
Dda Method

Hydraulic fracturing is one of the most important technologies for shale gas production. Complex hydraulic fracture networks can be stimulated in shale reservoirs due to the existence of numerous natural fractures. The prediction of the complex fracture network remains a difficult and challenging problem. This paper presents a fully coupled hydromechanical model for complex hydraulic fracture network propagation based on the discontinuous deformation analysis (DDA) method. In the proposed model, the fracture propagation and rock mass deformation are simulated under the framework of DDA, and the fluid flow within fractures is simulated using lubrication theory. In particular, the natural fracture network is considered by using the discrete fracture network (DFN) model. The proposed model is widely verified against several analytical and experimental results. All the numerical results show good agreement. Then, this model is applied to field-scale modeling of hydraulic fracturing in naturally fractured shale reservoirs. The simulation results show that the proposed model can capture the evolution process of complex hydraulic fracture networks. This work offers a feasible numerical tool for investigating hydraulic fracturing processes, which may be useful for optimizing the fracturing design of shale gas reservoirs.

Numerical Simulation of Coal Mining Excavation Based on Discontinuous Deformation Analysis

2011 ◽  
Vol 138-139 ◽  
pp. 187-192
Author(s):  
Ya Nan Gao ◽  
Feng Gao ◽  
M.R. Yeung ◽  
Qing Hui Jiang
Keyword(s):  
Underground Mining ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Rock Stratum ◽  
Deformation Problem ◽  
Excavation Process ◽  
Discontinuous Deformation ◽  
Movement And Deformation ◽  
Dda Method ◽  
The Continuum

The movement and deformation of rock stratum occur when the excavation is carries out during the underground mining process. Rock is a continuous-discontinuous material so the continuum mechanics method may not handle the rock problem well. The discontinuous deformation analysis (DDA) method which discretizes the rock mass to block system can describe the large displacement and deformation of rock blocks, especially the rock stratum collapse. The DDA was employed in this paper to analysis a mining excavation process. The displacement field and stress field of rock stratum was computed. The result shows that the DDA can handle the mining excavation and the rock stratum movement and deformation problem well.

DISCONTINUOUS DEFORMATION ANALYSIS BASED ON VARIATIONAL INEQUALITY THEORY

2011 ◽  
Vol 08 (02) ◽  
pp. 193-208 ◽  
Author(s):  
WEI JIANG ◽  
HONG ZHENG
Keyword(s):  
Variational Inequality ◽  
Variational Inequality Problem ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Penalty Function Method ◽  
Weak Nonlinearity ◽  
Contact Conditions ◽  
Inequality Theory ◽  
Discontinuous Deformation ◽  
Dda Method

In the conventional discontinuous deformation analysis (DDA) method, the contact conditions are enforced by the penalty function method. Improperly selected penalty parameters might cause numerical problems. In order to evade the introduction of the penalty parameters and to avoid "open–close iteration" that can not assure convergence, this study reformulates the DDA as a variational inequality problem. Based on the fact that the solution of a variational inequality is a fixed point of a natural projection map, the problem is reduced to the solution of nonsmooth equations with weak nonlinearity. Then, the Path Newton Method (PNM) is utilized to solve the equations. Some practical examples originally designed by Shi are reanalyzed, which demonstrates that the new DDA method is feasible.

A Three-Dimensional Discontinuous Deformation Analysis Method for Investigating the Effect of Slope Geometrical Characteristics on Rockfall Behaviors

2019 ◽  
Vol 16 (08) ◽  
pp. 1850122 ◽  
Author(s):  
Guoyang Liu ◽  
Junjie Li
Keyword(s):  
Slope Angle ◽  
Three Dimensional ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Motion Trajectories ◽  
Geometrical Characteristics ◽  
Damage Degree ◽  
Slope Excavation ◽  
Discontinuous Deformation ◽  
Dda Method

In the present study, a three-dimensional discontinuous deformation analysis (3D DDA) method was developed and used to investigate the effect of slope geometrical characteristics on rockfall behaviors. The slope geometrical characteristics of rockfall, such as the slope height, slope angle and slope shape, were summarized, and the corresponding calculation models were proposed. The algebraic computation and contact mechanics of the three-dimensional (3D) global contact theory were illustrated and implemented into the 3D DDA method. The accuracy of the developed 3D DDA method was verified through the four basic movement forms of rockfall: freefalling (oblique projectile), sliding, rolling and bouncing. Numerical examples were performed to study rockfall behaviors under different slope geometrical characteristics by analyzing the kinetic energy or velocity conversion, motion trajectories, and damage degree and range of moving blocks. The results demonstrate that the 3D DDA method can accurately simulate rockfall movement, which is significantly affected by slope geometrical characteristics. Furthermore, some suggestions for slope excavation and protection were put forward.

USE OF DISCONTINUOUS DEFORMATION ANALYSIS TO EVALUATE THE DYNAMIC BEHAVIOR OF SUBMARINE TSUNAMI-GENERATING LANDSLIDES IN THE MARMARA SEA

2011 ◽  
Vol 08 (02) ◽  
pp. 151-170 ◽  
Author(s):  
GUI CHEN MA ◽  
FUMIO KANEKO ◽  
SHINZABURO HORI ◽  
MAKOTO NEMOTO
Keyword(s):  
Energy Loss ◽  
Dynamic Behavior ◽  
Jointed Rock ◽  
Slope Instability ◽  
Discontinuous Deformation Analysis ◽  
Viscous Force ◽  
Deformation Analysis ◽  
Marmara Sea ◽  
Submarine Landslides ◽  
Discontinuous Deformation

This study assessed the relevance of numerical modeling with respect to the mechanical properties of specific rock and investigated the applicability of submarine landslide simulation using discontinuous deformation analysis (DDA). To predict the dynamic behavior of submarine landslides, we developed a way to model a jointed rock mass for the evaluation of rock slope instability and an original DDA approach using an energy loss model that incorporates energy loss caused by collision between blocks and seawater resistance as a viscous force. We applied the developed model to estimate the dynamic behavior of actual submarine landslides. The simulations assessed seawater resistance and energy loss due to collision between blocks, reproducing past events and suggesting the behavior of vulnerable slopes. The results demonstrate that the model can clarify the energy loss caused by slope absorbability and seawater resistance, and that the improved DDA is very useful for submarine land analysis.

TUNNEL BLASTING SIMULATIONS BY THE DISCONTINUOUS DEFORMATION ANALYSIS

2011 ◽  
Vol 08 (02) ◽  
pp. 277-292 ◽  
Author(s):  
ZHIYE ZHAO ◽  
YUN ZHANG ◽  
HUIRONG BAO
Keyword(s):  
Rock Mass ◽  
Dynamic Response ◽  
Influence Factors ◽  
Blast Loading ◽  
Rock Fragmentation ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Tunnel Blasting ◽  
Discontinuous Deformation ◽  
Drill And Blast

Drill and blast method has been widely used as an effective excavation method for underground rock caverns or tunnels. To achieve a good blast design, an understanding on the rock dynamic response and rock fragmentation process is important. In this paper, numerical simulations are performed on a typical parallel hole cut blasting based on the discontinuous deformation analysis (DDA). The blast loading is obtained from the explicit FEM code LS-DYNA and the dynamic response of the rock mass is modeled by the DDA. Different influence factors on rock fragmentation under the blast loading are investigated, including the different delay time and various rock mass properties. Such a study will have potential applications for better drill and blast designs.

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