关键词: 地铁隧道, 地表沉降, 有限元方法, 地层损失率, 地应力释放率

Abstract: The transverse surface settlement induced by shield tunneling of Shenyang Metro Line 1 is analyzed by finite element method. The concepts of ground loss and ground stress release are introduced, and the finite element models under different ground loss rates and ground stress release values are established. The comparison results between monitored surface settlement and simulated values show that the surface settlement is proportional to the ground loss rate and the ground stress release rate. And then, by comparing the maximum settlement value of the monitored data and simulated values, it is determined that the ground loss rate caused by the construction is 1.747%, and the ground stress release rate is 74.071%. Similarly, it is determined that the ground loss rate in 10 cities caused by tunnel construction ranges from 0.5% to 2% and the ground stress release rate ranges from 60% to 80%. Finally, the maximum bending moment at the lining concrete segment of the FEM model with the ground loss rate of 1.747% and ground stress release rate of 74.071% is compared with that without ground loss and ground stress release, and the comparison results show that the maximum bending moment value significantly reduces by 76.16% and 71.82%, respectively. The bending moment values obtained by the two methods are basically the same, which indicates the equivalence of ground loss rate model and ground stress release model.

Key words: metro tunnel, surface settlement, finite element method, ground loss rate, ground stress release rate