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Analysis on Seismic Response of Shield Tunnels Passing Through Soil-Rock Strata
(1 Department of Geotechnical Engineering College of Civil Engineering, Tongji University, Shanghai 200092; 2 Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education, Tongji University, Shanghai 200092;3 China Railway Siyuan Survey and Design Group Co., Ltd., Wuhan 430063; 4 Shanghai Construction No.1 (Group) Co., Ltd., Shanghai 200120)
Abstract When a tunnel passes through soil-rock strata, it is the key controlling link for the seismic design of the structure. In order to explore the aseismic safety of a shield tunnel passing through strata with varying stiffness, taking a shield tunnel project in Nanjing as the background, a 3D finite element model of shield tunnel-strata is established considering the characteristics of soil-rock varying strata. Then, the dynamic time history analysis method is adopted to study the seismic response law of the shield tunnel passing through soil-rock strata. The results show that the acceleration and displacement responses of strata and tunnel are significantly different in soil-rock interface section, soil section and rock section under the same buried depth condition; as for the seismic wave, the spectrum amplification effect of the tunnel and the strata in the soil-rock interface presents much more the spectrum characteristics in harder rock stratum; when the ground motion is input parallel to the tunnel axis, the peak values of internal force and deformation response in the shield tunnel structure occur at the soil-rock interface, the abrupt change of stratum stiffness leads to significant amplification of seismic response of the tunnel structure passing through the stratum, which should be specially paid attention to in the seismic design.
Abstract：
When a tunnel passes through soil-rock strata, it is the key controlling link for the seismic design of the structure. In order to explore the aseismic safety of a shield tunnel passing through strata with varying stiffness, taking a shield tunnel project in Nanjing as the background, a 3D finite element model of shield tunnel-strata is established considering the characteristics of soil-rock varying strata. Then, the dynamic time history analysis method is adopted to study the seismic response law of the shield tunnel passing through soil-rock strata. The results show that the acceleration and displacement responses of strata and tunnel are significantly different in soil-rock interface section, soil section and rock section under the same buried depth condition; as for the seismic wave, the spectrum amplification effect of the tunnel and the strata in the soil-rock interface presents much more the spectrum characteristics in harder rock stratum; when the ground motion is input parallel to the tunnel axis, the peak values of internal force and deformation response in the shield tunnel structure occur at the soil-rock interface, the abrupt change of stratum stiffness leads to significant amplification of seismic response of the tunnel structure passing through the stratum, which should be specially paid attention to in the seismic design.
LI Siming1 YU Haitao2 XUE Guangqiao3 XU Lei4
.Analysis on Seismic Response of Shield Tunnels Passing Through Soil-Rock Strata[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(5): 65-72
2021, Vol. 58 