Design of a type of strike-slip active fault container for shaking table tests

Fault container and shaking table tests are crucial for studying co-seismic dislocation in cross-fault tunnels, with the design and functionality of the container significantly affecting the accuracy of dynamic response analyses of tunnel linings. This research introduces a fault container developed as part of a significant active fault-crossing tunnel project in the high-intensity seismic zone of western China. The container is designed to simulate both strike-slip and dip-slip fault characteristics with adjustable fault angles. Extensive testing, including shaking table tests under strong seismic conditions, three-dimensional (3D) finite element numerical simulations, and hammer tests, were conducted to evaluate the modal characteristics of the container under various conditions. The study highlights the resonance characteristics of the soil-container system, the signal consistency across different dislocations, and the dynamic response patterns both with and without pulse-like seismic motions and varying intensities. The results indicate that the natural frequencies of the container and the model soil, determined through white noise scanning, are 23.74 Hz and 6.355 Hz, respectively, suggesting no resonance in the model soil-container structure. The dynamic response characteristics of the empty container show good integrity and versatility under various seismic excitations. The consistency of the free-field time history curve confirms that the newly developed fault container effectively simulates the continuity and boundary conditions of the free-field. Time domain analysis conducted before and after fault dislocation demonstrates the capability of the container to accurately replicate the coupling effects of fault and seismic motions.