盾构隧道施工过程地表变形的数值模拟计算

Numerical Simulation Calculation on Surface Deformation During Shield Tunnel Construction

为研究盾构隧道在掘进过程中地表不同点的位移变化,建立盾构隧道掘进的有限元模型,对盾构隧道的开挖进行了有限元数值模拟.结果表明:盾构隧道在掘进过程中,会导致地下土体应力释放,使地表土发生相应沉降,并且隧道纵向轴线正上方地表点的沉降变形最大.当掘进距离超过一定深度后,其后方较远地表点的沉降变形趋于稳定.盾构的顶推力会导致其前方一定范围的地表土发生向上隆起.在注浆层硬化前、后过程中,不论是拱脚、拱顶及对应地表点的沉降位移均会比注浆层硬化前要大.

In order to study the displacement change of the surface points above the shield tunnel during the actual process of construction, 3 - D finite element model of the shield tunnel driving is established. And the actual process of construction is simulated by the model. The results indicate that the soil - stress - release and ground settlement will occur during the actual process of shield tunnel construction. At the same time, the maximum consolidating set- tlement of the surface points is above the tunnel longitudinal axis, and the consolidating settlement of the surface points will tend to be stable when the digging distance is deeper. The jacking force of the shield tunnel can make a certain range of the top soil layer uplift. The skewback, the vault and the corresponding surface points will increase with the hardening of the grouting layer.