Shake Table Testing to Quantify Seismic Soil-Structure-Interaction of Underground Structures

This research uses shake table testing of scale soil-structure models to mimic the coupled seismic response of underground structures and surrounding/supporting soil (termed soil-structural-interaction or SSI). Currently the seismic design of subways and other critical underground infrastructure rely on little to no empirical data for calibrating numerical simulations. This research is working towards filling that empirical data gap. The research is composed of two phases, the first a validation of the free-field response of a flexible wall barrel filled with model soil, the second a test to measure the “racking” deformations induced in a model subway cross-section embedded in the model soil. San Francisco Young Bay Mud (YBM) is used as the prototype soil and the Bay Area Rapid Transit (BART) underground subway cross-section the prototype structure. Results are shown from the completed first phase of the test, and a presentation of the second phase test results is anticipated at the time of the conference. This research is a collaborative project between California Polytechnic State University (Cal Poly) in San Luis Obispo, California, and Nanjing University of Technology (NJUT) in Nanjing, China