Numerical Analysis and Shaking Table Test of Seismic Response of Tunnel in a Loess Soil Considering Rainfall and Traffic Load

A tunnel driven in loess soil in an earthquake-prone area may be subject to a variety of other external actions. Considering the coupling effect of earthquake activity, rainfall seepage and traffic movement, a dynamic model of a two-lane tunnel driven in a loess soil and a model of rain seepage are established. Using near-field pulse earthquake excitation, the influences of tunnel driven in a loess soil seepage, traffic load and earthquake activity on the dynamic responses of tunnel driven in a loess soil are studied. The variation laws of the first principal stress, the third principal stress, the displacement, the acceleration and the pore water pressure of tunnel driven in a loess soil with different rainfall amounts and burial depths are discussed. Considering the unfavorable conditions of El-Centro ground motion and rainfall seepage, the ground motion response rule of loess tunnel is studied based on the 1/40 shaking table model of loess tunnel. The results show that, at the same burial depth, the stress, displacement and pore water pressure increase with the rainfall amount; for different burial depths, according to the extreme value of the stress, displacement and the pore water pressure, the locations of antiseismic reinforcement measures are determined. The research results can provide a reference for the design and construction of tunnel driven in a loess soils under complex stress coupling.