地铁换乘站深基坑内支撑体系的优化设计与分析

采用土体卸载条件下的Hardening-Soil有限元模型,研究苏州某地铁换乘站深基坑3种支撑方案对支护结构内力和基坑变形的影响。结果表明:与初始方案比较,方案A(去掉第4道支撑)的墙身最大侧移增大了35.28%,最大正负剪力分别增加41.87%和71.11%,最大正负弯矩分别增加145.32%和45.39%,最后一道支撑轴力达到1018kN,比初始方案增加了近1倍,对基坑土体变形影响增长近10%;方案B(第3、4道支撑合并)的墙身最大侧移增大了10.49%,最大正负剪力则增加6.89%和33.97%,最大正负弯矩增加34.46%和10.97%,合并后的第3、4道支撑轴力降低了15%,对基坑土体变形影响较小。方案B既能保证基坑安全和环境影响的要求,又能降低造价。

Optimization Design and Analysis of Support System in Deep Foundation Pit of Metro Interchange Station

The Hardening-Soil finite element model subject to unloaded soil mass is employed to study the influence of three kinds of supporting schemes on the internal force and deformation of the supporting structure in the deep foundation pit of a subway transfer station in Suzhou. The results show that the maximum lateral displacement of the wall increases by 35. 28% compared with the original scheme; the maximum positive and negative shear forces increase by 41. 87% and 91. 1% respectively; the maximum positive and negative bending moments increase by 145. 32% and 45. 39%; the last strut axial force increases nearly twice to 1018 k N; the influence on the foundation soil deformation grows by nearly 10%;the maximal lateral deformation in scheme B( the combination of third and fourth supports) increases by 10. 49% compared with the original scheme; the maximal positive and negative shearing forces increase by 6. 89% and 33. 97% respectively;the maximal positive and negative moments increase by 34. 46% and 10. 97% respectively;the combined strut axial forces of the third and fourth are reduced by 15% and the influence on the deformation of pit soil mass is very small. It is concluded that scheme B can not only guarantee the pit safety and environment impact but also save the engineering cost.