Numerical Simulation of Dynamic Response Law of Intersecting Metro Tunnels in Upper and Lower Strata

With the acceleration of urbanization process, more and more urban subway construction, inevitably space intersection of subway tunnels has been formed. Based on practical engineering cases, a three-dimensional model is established by using MIDAS-GTS/NX numerical software. The dynamic response of metro tunnel under seismic wave is analyzed. The effect of tunnel intersection angle on the dynamic response law is discussed. The results show that: (1) Acceleration amplification factor, internal force and displacement of intersecting tunnels increase first and then decrease along the measuring points. The dynamic response of the area where the upper and lower tunnels intersect is the strongest. (2) The dynamic response of the tunnel in the upper soil is stronger than that in the lower rock. The difference of dynamic response between two tunnels in the same stratum is small. (3) With the increase of the intersection angle between the upper and lower tunnels, the acceleration and shear force decrease gradually. There is a negative correlation. The exponential function is established to describe the functional relationship between the dynamic response and the angle. The research results can provide references for earthquake resistance and shock absorption of urban metro.