软弱地层顶管法施工扰动分析及变形控制方法

Disturbance Analysis and Deformation Control Method for Pipe Jacking Construction in Soft Strata

顶管法施工不可避免对土层产生扰动,为明确顶管法施工引起的地层失稳以及地表沉降变形,以昆明市5号线弥勒寺站顶管工程为背景,通过FLAC^(3D)分析顶管法施工的变形和力学特性,探究顶管法施工过程对土层的扰动机理,进而提出相应的沉降控制措施。结果表明:顶管法施工对地层扰动引起土体的刚度减弱,对地层的影响范围为顶进面Y轴方向-5 m~5 m。针对地层的特性、以及顶管法施工的扰动机制,通过合理的注浆措施对土层刚度进行强化。控制顶管法施工全阶段可能造成的土层敏感变形值,同时,通过注浆加固能够有效降低顶管法施工过程的侧摩阻力,进而控制施工引起的地层扰动变形。顶管法顶进施工产生的正向顶进力和地层损伤的叠加作用是导致地层变形的主要因素。

Since pipe jacking construction inevitably disturbs the soil layer,in order to clarify the ground instability and surface settlement and deformation caused by pipe jacking construction,the deformation and mechanical character-istics of pipe jacking construction are analyzed by FLAC^(3D) with the background of the pipe jacking project of Mile Tem-ple Station of Line 5 in Kunming City,and the disturbance mechanism of the soil layer is investigated during the process of pipe jacking construction,and then corresponding settlement control measures are proposed.The results are as follows.The superposition of positive jacking force and formation damage generated by pipe jacking construction is the main factor leading to the deformation of the formation,and the disturbance of the formation caused by pipe jacking construction weakens the stiffness of the soil body,and the influence on the formation ranges from-5 m to 5 m in the Y-axis direction of the jacking face.In order to control the sensitive deformation of the soil layer caused by the pipe jacking construction,the soil layer stiffness is strengthened by reasonable grouting measures,and the sensitive deform-ation of the soil layer caused by the pipe jacking construction is controlled,at the same time,the lateral friction resist-ance during the pipe jacking construction process can be effectively reduced by grouting reinforcement to control the disturbing deformation of the ground layer caused by the construction.