明挖隧道施工引起地面沉降的全过程模拟研究

Full-process Numerical Simulation of Ground Settlement due to the Tunnel Built by Cut and Cover

文章采用ABAQUS软件对某湖底隧道建设引起的土层位移和地面沉降进行了全过程三维模拟,模拟结果表明:不同施工阶段对地面沉降的贡献不同,止水帷幕施工引起的沉降很小,降水(尤其是第一次降水)则会引起明显的地面沉降,而放坡开挖会使地表回弹,且越靠近基坑边缘回弹越明显。隧道结构施工及土体回填对地面沉降的贡献最大,特别是在临近基坑边缘处。因此,研究明挖隧道施工引起的地面沉降时,不仅要考虑基坑降水和开挖环节,还需考虑结构施工及土体回填环节对地表的影响。

ABAQUS is used in this paper to three-dimensionally simulate the soil displacement and ground settlement due to the construction of a tunnel underlying a lake bottom.The simulated results show that the contribution of different construction stages to the ground settlement is various.Ground settlement caused by the construction of waterproof curtain is very small,while dewatering,especially the first-step dewatering,can result in significant ground settlement.Slope excavation can cause ground rebound,and the rebounding increases with the decreasing distance to the pit edge.The greatest contribution comes from the construction of tunnel structure and the following backfilling,especially in the vicinity of the pit edge.Consequently,it is necessary to cover the construction of tunnel structure and backfilling when evaluating ground settlement due to tunnel construction.