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.

scholarly journals A Stochastic Rockfall Model Related to Random Ground Roughness Based on Three-Dimensional Discontinuous Deformation Analysis

2021 ◽  
Vol 9 ◽  
Author(s):  
Lu Zheng ◽  
Zhiyuan Zhu ◽  
Qi Wei ◽  
Kaihui Ren ◽  
Yihan Wu ◽  
...  
Keyword(s):  
Dynamic Behavior ◽  
Lateral Displacement ◽  
Grid Point ◽  
Slope Angle ◽  
Three Dimensional ◽  
Discontinuous Deformation Analysis ◽  
Cumulative Distribution ◽  
Deformation Analysis ◽  
Discontinuous Deformation ◽  
The Impact

The use of feasible 3-D numerical methods has become essential for addressing problems related to rockfall hazard. Although several models with various degrees of complexity are available, certain trajectories and impact dynamics related to some model inputs could fall in the rockfall observations area but are rarely calibrated against reflecting its range, especially the lateral deviations. A major difficulty exists in the lack of simulating the apparent randomness during the impact-rebound process leading to both ground roughness and block irregularities. The model presented here is based on three-dimensional discontinuous deformation analysis (3-D DDA). Despite similarities to previous simulations using 3-D DDA, the model presented here incorporates several novel concepts: (1) ground roughness is represented as a random change of slope angle by height perturbation at a grid point in DEM terrain; (2) block irregularities are modelled directly using polyhedron data; (3) a scaled velocity restitution relationship is introduced to consider incident velocity and its angle. Lateral deviations of rebound velocity, both direction and value, at impact are similarly accounted for by perturbing the ground orientation laterally, thus inducing scatter of run-out directions. With these features, the model is capable to describe the stochastic rockfall dynamics. In this study, 3-D DDA was then conducted to investigate the dynamic behavior of the rockfall and examine the role of sphericity of the rock block travelling on bench slopes with different ground roughness levels. Parametric analyses were carried out in terms of cumulative distribution function (CDF) to investigate for spatial distribution (both runout distance and lateral displacement), velocity and jumping height. The effects of block shape and ground roughness revealed by these factors were discussed. It suggests that ground roughness amplifies the randomness and plays important roles on the dynamic behavior of the system; irregularity from block sphericity will further amplify the randomness especially when the size of the rock is relatively small compared to the roughness level. Both irregularities should be taken into consideration in simulating rockfall problems. Further calibration of the new model against a range of field datasets is essential.

Study on the Impact of Lateral Pressure on Jointed Rock Mass with DDARF Method

2014 ◽  
Vol 1044-1045 ◽  
pp. 607-611
Author(s):  
Cheng Long Zhao ◽  
Wei Shen Zhu ◽  
Shu Cai Li ◽  
Hai Ping Ma
Keyword(s):  
Compression Test ◽  
Lateral Pressure ◽  
Jointed Rock ◽  
Discontinuous Deformation Analysis ◽  
Biaxial Compression ◽  
Deformation Analysis ◽  
Inhibiting Effect ◽  
Discontinuous Deformation ◽  
The Impact ◽  
Initiation Stress

The discontinuous deformation analysis for rock failure (DDARF) method is adopted to simulate the biaxial compression test under different lateral pressure conditions. Then this paper analyzes the impact of the lateral pressure on the specimen failure rules. The simulation results show that the lateral pressure has obvious inhibiting effect on the expansion of wing cracks, crack initiation stress, and specimen peak strength.Keywords: Multi-joint specimen; DDARF method; Lateral pressure; Biaxial compression test simulation

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