盾构法施工对地层位移影响的数值模拟

隧道地层的初始应力、开挖形成的空间效应和开挖支护过程等都会对地层沉降和水平位移产生影响。文章通过建立反映工程特性的有限元模型,以隧道围岩中过横断面圆心的竖线和不过圆心的竖线为代表,用ELAC3D软件计算了各点的沉降和水平位移随开挖面前进的变化规律。结果表明:盾构法施工过程使开挖面前后的横断面都发生竖直方向和水平方向位移,隧道横断面变成横向长、竖向短的椭圆形,开挖过的断面距开挖面越远,椭圆变形越明显,同时向后的水平位移越大,未开挖面距开挖面越近,椭圆变形越大,同时向前的水平位移越大。

Numerical simulation of the effects of shield construction on the ground movement of the tunnel

The initial ground stress, space effects of excavation and construction progress have many effects on settlement and horizontal engineering characteristics is built in movement of ground. Finite element model which reflects this paper. Two vertical lines are selected as examples been studied. The one is across the centre of the circle and the other one is not across the centre of the circle. FLAC3D is used to calculate the variety law of settlement and horizontal movement as the excavation area goes ahead. The research results reveal that the vertical and horizontal displacement of ground occur with the shield tunnel excavation. The cross sections become ovals which are long in vertical distance and short in horizontal distance. The excavated sections longer away from the excavation section have bigger vertical deformation and backward horizontal displacement. The sections without excavation in shorter distance away from the excavation section have bigger vertical deformation and beforeward horizontal displacement.