| dc.description.abstract |
Taiwan is located at the junction of the Eurasian plate and the Philippine Sea plate. Engineering design often takes into account the effects of earthquakes. In recent years, such as Taiwan Chi-Chi earthquake, China Wenchuan earthquake, Japan Fukushima earthquake and other active faults caused serious damage to life and property. In order to explore the effect of fault on the surface and underground structure, physical tests were usually carried out by Centrifuges in the past. However, physical test is time-consuming and expensive. Therefore, many studies consider the use of Finite Element Method (FEM) and Discrete Element Method (DEM) to simulate in recent year. However, when the fault deformation is too large, the FEM will have a greater error, so in order to get results that are more accurate, this study used DEM for reverse fault simulation.
This study referred to the numerical model of sandbox test from Chang (2013). A sandbox test with a maximum vertical displacement of 5cm was simulated at 80g by using PFC2D (Particle Flow Code in Two Dimensions). In order to understand the stress changes in different locations, The model in accordance with the depth into shallow, medium and deep, and then in accordance with the horizontal position into the hanging wall, the transition zone, the footing wall. Then, set the measurement circle by the above principle. The simulation result show that the lateral force of the fault, the boundary effect and the development of the shear zone mainly affected the stress state. Lateral force and the boundary is the most important factor in controlling the principal stress direction. The shear zone mainly affect the transition zone. In order to further understand the relationship between the microstructure and the stress state during fault offsetting, in the analysis of pore change and volumetric strain, it could be found that the state of particle arrangement changed, when the shear zone occurred, stress state became quite complicated. Finally, we discuss the destructive behavior in fault simulation through the shear strain analysis, and hope to know more about the potential threat of fault. | en_US |