盾构隧道叠交施工引起的土层位移场分布规律

Distribution of ground displacement field owing to two overlapped shield tunneling interaction

考虑盾构隧道叠交施工之间的相互影响,应用边界单元法对相邻隧道开挖过程中的三种典型叠交位置关系,引起的地层位移场分布规律及相互影响进行分析。分析结果表明:单条隧道开挖引起的地表最大沉降值出现在隧道轴线的正上方,而两左右或上下相邻隧道开挖的地表及土层内部的最大沉降值则出现在两隧道的纵轴线之间,且偏向上方埋深较浅的隧道。隧道开挖引起的地层深层与浅层变形趋势是一致的,但在两隧道轴线上方深层土体的沉降要远比浅层土体大。叠交隧道的埋深及其相对空间位置关系对土层的位移场有较大的影响。

Considering the interaction of overlapped shield tunneling, the boundary element method was applied to analyze the ground displacement distribution and interaction between two adjacent tunnels in three typical situations. It was shown that the maximum displacement occurred on the tunnel axis when one tunnel was excavated, while the maximum value happened near the shallow tunnel and between the area of two tunnels when two adjacent tunnels were excavated at the same time. The tendency of deformation of deep stratum was consistent with that of the shallow stratum, but the settlement of deep stratum over the tunnel was far larger than that of the shallow stratum. The embedded depth and relative location of two tunnels severely affected the disolacement field.