基于随机介质理论分析盾构隧道开挖引起的地表沉降

Analysis on ground settlement influenced by shield tunnel based on stochastic medium theory

有效预测并合理控制隧道开挖引起的土体变形和沉降、减小对周围土体及建筑物的影响对实际生产具有重要的现实意义。应用随机介质理论简化公式,基于上海虹梅南路隧道西线地表沉降监测数据,通过反分析计算的方法得到隧道开挖导致的断面收敛面积ΔA及主要影响角tanβ,并对这两个主要参数与隧道埋深或相对埋深之间的关系进行了研究。结果表明:计算值和实测值较吻合,对于浅埋隧道,ΔA的取值较大且较离散;随着隧道埋深的增加,当隧道埋深大于20m时,ΔA的取值较稳定,且大部分处于0.2~0.4m^2之间。tanβ随着埋深或相对埋深的增加,整体呈现出增加的趋势,tanβ与埋深大致满足tanβ=0.035z-0.098的关系。

Effective prediction and reasonable control of soil deformation and settlement caused by tunnel excavation and reduction the impact on surrounding soil and buildings have important significance for actual production. The stochastic medium theory simplification formula is used, based on the monitored surface subsidence of the west line of Shanghai South Hongmei Road Tunnel. The tunnel section convergence area ΔA and the tangent value tan β of the main influence angle are obtained by back analysis. The relationship between buried depth or relative depth and the two key parameters are studied. The results showed that the calculated values are in good agreement with the measured values. For shallow buried tunnels, the value of ΔA is larger and more discrete. With the increase of tunnel depth, when the buried depth of the tunnel is greater than 20 m, the value of ΔA is stable, most are between 0.2 and 0.4 m^ 2. As the buried depth or relative depth increases, tan β generally shows an increasing trend, and the buried depth substantially satisfy the relationship of tan β=0.035 z -0.098.