水底明挖隧道深基坑流固耦合数值分析

摘要

According to the excvation situation of the foundation pit ,the seepage‐stress interaction is taken into account ,a FEM model of the foundation pit is established by Midas/GTS ,seepage and the stress field of foundation pit in different working states is simulated by finite element method .The calculate results show that :the vertical subsidence and horizontal displacement of the soil increase , the soil at the bottom of the pit swells ;the axial force of the column is compressive stress which first increases with the excavation depth and then decreases ,the max press is in the ending excavation sur‐face and less than code requirement ;the value and area of plastic zone increase with the excavation of the pit ,the location of the plastic failure happens in the excavation depth of 6m .%以福州市穿越晋安河水底隧道明挖法深基坑工程为依托，采用M idas／G T S建立基坑流固耦合有限元模型，分析了基坑开挖过程中周围应力场和渗流场的变化规律。结果表明，基坑周边的地层沉降、坑底隆起变形和围护结构的水平位均移随着开挖深度的增加而逐渐增大；基坑支护桩全部受压，其轴力随深度先增大后减小，小于设计值，且其最不利位置位于基坑最终开挖面深度处；塑性区随着开挖深度的增加而逐渐下移，发生塑性破坏的位置位于开挖深度6m处。