盾构施工对地表沉降的数值模拟分析

Numerical Simulation Analysis of Ground Settlement by Shield Construction

以合肥地铁3号线某区间隧道为工程背景,运用有限元数值模拟软件MADAS/GTS建立三维隧道施工的数值模型,计算隧道施工过程中引起的地表沉降。分析盾构施工在不同掘进距离条件下地表沉降的变形规律。模拟结果表明:在拱顶位置地表产生沉降最的大竖向位移。隧道下部围岩的最大隆起发生在拱底处;地表横向沉降范围随着开挖面的推进而不断加大,盾构施工的横向影响范围为隧道直径D的3倍。盾构施工造成的隧道下部围岩横向沉降影响范围约为洞径的2倍。

Taking the tunnel of a section of Hefei Metro Line 3 as the engineering background,the numerical model of 3 D tunnel construction was established using finite element numerical simulation software MADAS/GTS and calculate surface settlement caused by tunnel construction. The deformation of surface settlement under different tunneling distances of shield construction was analyzed. The simulation results showed that the most significant vertical displacement of the ground surface at the vault location occurred. The maximum bulge in the surrounding rock of the tunnel occurred at the bottom of the arch. Surface subsidence range continued to increase as the excavation surface advanced. The scope of horizontal effect of shield construction was 3 times the diameter of the tunnel. The scope of the lateral settlement of the surrounding rock in the lower part of the tunnel caused by shield construction was about 2 times the diameter of the tunnel.