矩形顶管施工引起的地面沉降变形研究

以南宁市轨道交通1号线南湖站Ⅰ号过街通道顶管工程为背景,分别考虑顶管机及后续管节对土体的作用力引起开挖面周围土体的施工时变形、土体损失引起地面永久沉降、注浆对土体损失补偿引起的地面抬升、地层中超孔隙水压力消散发生失水固结效应引起的工后沉降等因素,揭示了在注浆压力作用下矩形顶管隧道周围土体的变形模式,推导了由注浆填充引起的土体竖向变形计算方法,给出了扰动范围土体内超孔隙水消散引起的工后固结沉降的计算公式。运用Mindlin弹性理论解、随机介质理论、分层总和法分别对该工程由土体应力状态变化、地层损失、注浆填充和失水固结4个方面引起的地面变形进行计算,根据计算结果与实测数据的对比分析,对矩形顶管施工扰动引起的地表沉降变形特性进行系统研究,叠加后的计算结果与实测数据变化规律基本一致,且数值吻合较好。

Research on Ground Deformation Caused by Rectangular Pipe Jacking Construction

Taking Nanning rail transit Line 1 Nanhu station crossing pipe jacking construction as the background, respectively considering the influence factors of the acting force of the pipe jacking machine and subsequent pipe to the soil caused the brief deformation of soil around working face, the soil loss caused the ground permanent settlement, grouting filling on the loss of soil caused the surface uplift and the dewatering consolidation caused the post-construction settlement by the excess pore water pressure dissipation. This research reveals the rectangular pipe-jacking tunnel surrounding soils expansion deformation caused by the grouting pressure is similar to ellipse, and deduced to calculate vertical deformation of soil caused by it. The disturbed soil’s post-construction settlement caused by the dissipation of excess pore water pressure calculation formula is also given. The Mindlin solution, Random Medium Theory, method of layered summation are respectively used to calculate the ground deformation caused by the stress changes, the ground loss, the grouting fillings and the dissipation of excess pore water pressure. According to the comparison of the calculation results and the measured data, the surface deformation characteristics caused by the rectangular pipe jacking construction disturbance are presented. The changing rule of the superposition calculation results and the measured data are basically identical, and their values are very anastomosis.