Tunnel Longitudinal Seismic Response Analysis By Considering Traveling Wave Effect And Soil Heterogeneity

In order to maintain rapid development in recent years, most large-medium cities endeavor to build rail transits. Once the urban rail transits were seriously damaged, the urban transportation function would be heavily impacted and the economy would suffer a tremendous loss. The property of tunnel longitudinal seismic response needs further research, especially in the soil heterogeneity condition and when considering the traveling wave effect.In order to solve these problems, this article takes soil heterogeneity into consideration and studies on the differences of tunnel longitudinal seismic response when the seismic direction and wave velocity varies by inputting earthquake acceleration in phase difference.The main research contents are as follows:1. Fiber model is employed to calculate the mechanical property of tunnel. Considering the material property of concrete tunnel segment and joint bolt, this article has calculated the non-linear mechanical property of tunnel.2. By using PROSHAKE to accomplish the soil layers seismic response analysis, this article calculated soil effective shear modulus and soil effective damping ratio in different sections under KOBE earthquake.3. Several common calculation methods of soil spring property have been introduced. Based on the soil effective shear modulus and effective damping ratio, different models for different soil sections have been built and equivalent soil rigidity of different soil sections have been calculated.4. A three-dimensional soil model has been built to calculate the soil seismic response at the burial depth of tunnel under the action of uniform seismic ground motion and non-uniform seismic ground motion with traveling wave direction to the right and left. And the properties of soil seismic response under the action of uniform and non-uniform seismic ground motion with different apparent wave velocity have been analyzed.5. A spring-beam model has been built by using the moment–curvature relationship of tunnel and equivalent soil rigidity. By loading the displacement of soil at the burial depth of tunnel to the free end of soil spring, this article has calculated and analyzed the property of tunnel longitudinal seismic response under the action of uniform and non-uniform seismic ground motion with different apparent wave velocity.The result tells that the soil seismic response is more apparent in the region where soil is laterally inhomogeneous than that in the region where soil is laterally homogeneous. The soil and tunnel seismic response is more apparent under the action of non-uniform seismic ground motion. The traveling wave direction has an impact on the soil seismic response. Tunnel longitudinal seismic response is mainly affected by surrounding soil and tunnel longitudinal seismic design should take traveling wave direction and apparent wave velocity into consideration.