Seismic response analysis of close-distance cross tunnels: Shaking table test and numerical parameter analysis

Abstract

There are many research results on the seismic performance of single tunnel structure presently, but there are relatively few studies on the interaction of cross tunnels with different angles at close range during earthquakes, and the degree and scope of interaction between tunnels during earthquakes are not clear. A series of shaking table tests and numerical parameter analysis are conducted to study the interaction mechanism, influence degree and range of closely spaced intersecting tunnels under earthquake in this paper. The shaking table tests of soil-single tunnel, soil-upper and lower parallel tunnel and soil-upper and lower vertical tunnel are designed and performed firstly. The rationality of the numerical method is verified based on the test data accordingly. Finally, a comprehensive parameter analysis is carried out for the full-scale tunnel, in which the tunnel factors (crossing angle, diameter, buried depth), ground motion factors (type, amplitude) and the influence of site soil type were considered. The results show that the crossing angle between tunnels is the key factor affecting the seismic response of soil-tunnel system. The ground acceleration, internal force, and deformation of tunnel structure increase with the increase of crossing angle between tunnels, which should be paid more attention. In addition, the tunnel diameter, buried depth, seismic characteristics and soil type can significantly affect the response of tunnel structure. The research results can provide a reference for the seismic design of close-distance cross tunnel structures.