小净距盾构隧道施工诱发邻近建筑物沉降分析

Analysis of Adjacent Building Settlement Induced by Shield Construction of Small Spacing Tunnel

针对小净距穿越两栋建筑物的地铁盾构隧道施工引起地表沉降和两侧建筑物倾斜的问题,采用数值模拟方法分析盾构隧道施工对邻近建筑物及其桩基础的影响。结果表明:后行线(北线)开挖引起的隧道轴线上方地表沉降略小于先行线(南线),两者叠加形成的沉降槽呈偏W形;开挖面位置一定时,桩顶沉降大于水平位移,桩底沉降与水平位移接近;随着开挖面接近桩,桩顶沉降和桩底水平位移逐渐增大,在开挖面通过2倍洞径后桩底水平位移逐渐趋于稳定,在开挖面通过6倍洞径后桩顶沉降逐渐趋于稳定;随着开挖面接近桩,桩顶及桩底水平位移朝向隧道,桩中部则远离隧道。

In view of the problems of surface settlement and building inclination caused by the construction of metro shield tunnel crossing two buildings with small spacing distance,the numerical simulation method was used to analyze the influence of shield tunnel construction on adjacent buildings and their pile foundations.The results show that the surface settlement above the tunnel axis caused by the excavation of the latter line(north line) is slightly smaller than that of the earlier line(south line),and the settlement trough formed by the superposition of the two lines is in a W shape.When the position of the excavation surface is fixed,the settlement of the pile top is greater than the horizontal displacement,and the settlement of the pile bottom is close to the horizontal displacement.As the excavation face approaches the pile,the settlement of pile top and the horizontal displacement of pile bottom gradually increase.The horizontal displacement of pile bottom gradually tends to be stable after the excavation face passes 2 times the tunnel diameter,and the settlement of pile top gradually tends to be stable after the excavation face passes 6 times the tunnel diameter.As the excavation surface approaches the pile,the horizontal displacement of the pile top and pile bottom towards the tunnel,while the middle of the pile is far away from the tunnel.