Abstract：The seismic settlement in soft soil area is one of the main causes of earthquake damage, and its computational problem has always been a matter of great concern at home and abroad. In order to study the calculation of the seismic settlement of the subway tunnel in the soft soil area, taking the first phase project of the Tianjin Z2 subway tunnel as an example, combined with the geological survey report and the seismic safety evaluation report, the finite element analysis calculation method recommended by the “Geotechnical Investigation Procedures in Soft Soil Areas” (JGJ 83-2011) and the soft modulus theory is used to analyze and calculate the seismic settlement in soft soil area of the subway tunnel. The calculation results are compared with those of free field. The results show that the seismic settlement value at the location of the subway tunnel is larger than that under the free field at the same position, but there is little difference between the two values. The seismic settlement value of the tunnel can be estimated by the seismic settlement value of the free field. The scope of the tunnel seismic treatment can be limited to the diameter of the two tunnels around the central axis of the tunnel. The research has certain reference value for the similar subway tunnel projects in soft area.
