Response of Soil and a Submerged Tunnel During a Thrust Fault Offset Based on Model Experiment and Numerical Analysis

Observed from the earthquake disasters occurred over the decades in Taiwan, the deformation of near surface soil was the major cause lead to damages of underground structures or pipe lines; for instance, the damage of diversion tunnel of Shih-Kang Dam in Chichi earthquake is a typical case. To study the process of fault propagation as well as the associated soil and structure deformation during a fault offset event, model experiments of simulating thrust fault offset were set up, in which non-cohesive sands was adopted simulating near surface soil. The results, obtained from experiment studies and numerical analyses based on finite element method were then compared to further explore the behavior of soil, structure during faulting process. The soil deformation obtained from numerical analysis complies with the outcome from model experiments. In the near future, when conducting a risk evaluation for earthquake-induced damage on underground structure, a numerical stimulation can provides helpful quantity analysis and can serve as a handy tool for the earthquake resistance design.