Surface Settlement Induced by Subway Tunnel Construction Based on Modified Peck Formula

A surface subsidence model is established to address the issue of the increase in surface settlement with time. Considering the effects of time factors and depth on surface subsidence, the formula was derived and it was used to calculate the three-dimensional space–time prediction of two-line tunnel settlements in construction processes. Thus, we obtain the calculation method of ground settlement for single- and double-line tunnels. Research relies on Shenzhen Metro Line 7 project. On the basis of the comparison between FLAC 3D calculation software and on-site monitoring, the reliability of the proposed modified Peck formula for the calculation of surface settlement induced by shallow tunnel construction is verified. Research indicates that (1) the proposed calculation method for ground settlement induced by subway tunnel construction is accurate; (2) the modified Peck formula predicts soil settlement at different times and depths; and (3) the revealed surface settlement law is consistent with numerical simulation and measured results, which can effectively reveal the mechanism and law of surface settlement caused by tunnel excavation.