Analysis Of Deep Excavation Effect On Adjacent Underground Pipelines

The foundation pit excavation results in the change of the stress state of the original soil,resulting in the loss of the stratum and the displacement of the soil,so as to surrounding environment.It is very necessary to study the influence of foundation pit excavation on adjacent underground pipelines,which is of great practical significance to ensure the safe use of pipelines in the excavation of the foundation pit.This paper analyzes the excavation of foundation pit which is adjacent to underground pipelines with finite difference numerical software FLAC3 D,studying the displacement and internal force of pipeline under different conditions,discussing the effects of different forms of pipeline on the displacement of foundation pit retaining structure and the settlement of surrounding soil,verifying the reliability of numerical simulation by taking the deep foundation pit of a subway station in Hefei as the engineering background,analyzing the interaction between the station excavation and adjacent underground pipeline.The main contents of this paper are as follows:(1)This paper introduces the principle of formation damage caused by foundation pit excavation,expounding the mechanism of deformation and stress of underground pipeline caused by excavation,and the realization of FLAC3 Din the process of simulating the excavation of foundation pit.(2)To establish the 3D model unified system of pipeline-soil-foundation pit by using the numerical simulation software FLAC3 D,for studying the deformation and stress of the pipeline with different material,different buried distance from the foundation pit,different buried depth and different diameters in the reference to the soil in Hefei.(3)Based on the soil in Hefei,analyzing the effect on the horizontal displacement of foundation pit retaining structure and the settlement of the surrounding soil caused by single pipeline with different materials,different distance from the pit,different depth from the surface and different diameters and a plurality of pipelines in various arrangements.(4)Taked the deep foundation excavation of a subway station in Hefei as the project background,comparing the measured values of settlement with the numerical simulation results of adjacent underground pipeline to verify the reliability of the numerical simulation and the in-depth analysis of the engineering examples,studying on the deformation and internal force of the pipeline during the excavation of the foundation pit and the effect of pipeline on the retaining structure and surrounding soil.The research content of this paper is expected to provide a theoretical reference on normal use of underground pipeline during excavation of foundation pit and theoretical basis for the optimization design of foundation pit excavation,which is of important practical significance.