Experimental investigation of seismic performance of shield tunnel under near-field ground motion

Abstract

The near-field ground motion is one of the challenges to underground structure in soft soil site. In order to study seismic performance of shield tunnel under near-field ground motion, a series of large-scale shaking table tests are conducted. A refined tunnel lining is developed to capture the extension/closure response of joints. The difference of seismic response of shield tunnel under near field ground and far field ground motion is compared and analyzed. The findings show that compared with far-field ground motion, the acceleration response of segmental lining, cross-sectional deformation, extension/closure of longitudinal joints, dynamic normal earth pressure, and strain on segmental lining are increased obviously under the action of near-field ground motion. The near-field ground motion significantly stimulates the response of the tunnel structure in a wider low frequency range. The adverse effect of near-field ground motion on shield tunnel in soft soil site is significantly greater than that of far-field ground motion.