隧道盾构施工对既有桩群的影响研究

Study on the Influence of Tunnel Shield Construction on Existing Pile Groups

以深圳地铁九号线下穿联城变电站为例,对施工过程中盾构机穿越桩基的过程进行动态模拟。通过Midas GTS NX对单桩在施工过程中所受到的弯矩以及群桩桩基剪力随盾构开挖的变化规律进行了分析。分析结果表明,单桩变形以水平位移为主,处于隧道轴线水平切割桩基的交点附近,桩所受到的弯矩最大;群桩的桩基剪力的变化幅度随着距开挖区域的距离越远而变小,桩基受盾构施工产生的剪力方向主要为垂直盾构施工的方向。

Because of the movement of the stratum caused by the shield tunneling in the subway tunnel,the strata movement will cause additional deformation of the pile and additional internal forces,which will affect the stability of the pile foundation.Taking the Shenzhen Metro Line 9 below the Suburban Substation as an example,the process of the shield machine passing through the pile foundation during the construction process is dynamically simulated in this paper.Through Midas GTS NX,the bending moments of piles subjected to the construction process and the variation of pile group shear force with shield excavation were analyzed.The analysis results show that the single pile deformation is dominated by the horizontal displacement,and the bending moment of the pile is near the intersection of the pile foundation at the horizontal axis of the tunnel axis;The farther of the distance from the excavation area is,the smaller of the variation range of the shear force of the pile group will be;the direction of the shear force generated by the shield construction of the pile foundation is mainly the direction of the vertical shield construction.