大断面矩形顶管隧道施工围岩变形与力学特性

Deformation and Mechanical Performance of Surrounding Rock in a Large-section Rectangular Pipe-jacking Tunnel Contruction

针对城市繁华地段大断面矩形顶管隧道施工引起围岩扰动与破坏问题,依托郑州市红专路大断面矩形顶管隧道实际工程,采用FLAC^(3D)有限差分法数值计算,建立三维数值模型,进行了大断面近距离多个平行矩形顶管隧道施工围岩变形与力学特性的研究。研究表明:大断面近距离多个平行矩形顶管引起的地面沉降与沉降槽宽度,后期顶管施工影响明显大于先期施工;在顶管隧道顶进过程,靠近始发井围岩沿隧道轴线方向围岩土体切应力较大,远离始发井切应力较小;考虑了盾构机的掌子面推力与盾壳,管节顶进过程的泥皮套摩阻力,同步注浆压力,提出一种综合考虑盾构机、管节顶进以及同步注浆的三维数值模拟方法。

Focusing on the surrounding rock disturbance and damage caused by the construction of large-section rectangular pipe jacking tunnel in this particular area, a large section rectangular pipe jacking tunnel located in Hongzhuan road, Zhengzhou, was taken as an example. The FLAC3 D finite difference method was used to calculate the surrounding rock deformation and mechanical performance of large-section parallel rectangular pipe jacking tunnels within a close range. Results indicate that: the maximum ground settlement and the settlement tank width caused by the soil loss of the post-construction pipe jack are greater than those of the pre-constructed pipe jacking tunnels;during the jacking process of the tunnel, the surrounding rock near the starting shaft has a large shear stress along the axis of the tunnel, and the shear stress is lower for those far from the starting well;considering the thrust of the face of the shield machine, the mud-sleeve friction resistance of the jacking process of both pipe joint and shield shell, and the simultaneous grouting pressure, a 3 D numerical simulation method was proposed which considers the shield tunneling machine, pipe jacking and simultaneous grouting.