黄土地层盾构隧道开挖对地表沉降影响的有限元分析

基于黄土地层，采用邓肯-张非线性弹性本构模型，考虑盾构隧道开挖过程对周边建筑物的影响，建立了盾构隧道衬砌与土体相互作用的有限元计算模型．对黄土地层中盾构隧道外径和埋深及其与邻近建筑物的距离对地表及相邻建筑物沉降的影响规律进行了数值分析，结果表明：在相同盾构外径下，地面沉降随隧道埋深的增加几乎呈线性减小趋势；在相同隧道埋深下，地面沉降随盾构外径的增加几乎呈线性增大趋势；无论盾构外径如何，隧道顸部及相邻建筑物处的地表沉降值均随隧道和建筑物水平距离与盾构外径比的增大而减小，也随隧道埋深的增大而减小．文中给出了受沉降影响较大的范围，可为地下工程施工时对周边建筑物及地基采取加固措施提供理论依据，并为西部地区的地下工程建设提供参考．

Finite Element Analysis for Influence of Shield Tunneling on Settlement of Ground Surface in Loess Strata

According to the mechanical characteristics of loess soils, the Duncan-Chang non-linear elastic constitutive model was adopted. Considering the effect of excavation of shield tunneling on adjacent buildings, a finite element model on the interactions between soil and lining was established. The law of the influence of shield tunneling on settlement of ground surface in loess strata was discussed, and the results indicate that the settlement of ground surface reduces near-linearly with the increasing depth of tunnel in the same outer diameter of shield tunneling; the settlement of ground surface increases near-linearly with the increasing outer diameter of shield tunneling in the same depth of tunnel; and no matter what size the outer diameter of shield tunneling is, the settlements of ground surface above the tunnel and the adjacent buildings reduce with the increasing ratio of the horizontal distance between the shield tunneling and the building to the outer diameter of shield tunneling, and also reduce when the depth of tunnel increases. This research offers a theoretical reference to the construction of metro engineering in west China.