Influence Of Deep Foundation Pit Excavation On Surrounding Buildings And Underground Pipelines

With China accelerates the pace of urbanization,deep foundation pit engineering plays a more and more important role important in urban construction.While deep foundation pits usually locate in the urban key area which exists a great deal of buildings and underground pipelines.Surface settlement,diaphragm wall displacement and foundation pit bottom uplift may occur in the course of foundation pit.The problem studied in this paper has certain practical significance for purpose of protection of surrounding buildings and normal function of underground pipelines during foundation pit excavation.Taking Gushuyuan subway foundation pit in Zhengzhou as an example,this paper establishes the model of foundation pit and its surrounding buildings and underground pipelines through Midas GTS NX,through the comparative analysis of the calculated cloud images and the actual monitoring conditions,some conclusions are drawn,which have a certain reference value for similar projects in this region,The research contents of this paper are as follows:(1)The development of foundation pit engineering at home and abroad is summarized and described to a certain extent.(2)The influence and damage of foundation pit excavation on surrounding buildings and underground pipelines are summarized theoretically,and the damage forms are summarized.(3)The geological and hydrological conditions of foundation pit are listed in detail,and the method and location of engineering monitoring and analysis are introduced.(4)A brief introduction of MIDAS GTS NX software,and then the C area foundation pit as the object of modeling analysis,numerical simulation.According to the numerical simulation results,the larger the excavation depth is,the larger the surface settlement around the foundation pit is.The maximum settlement is 8m,and the maximum settlement is 8.5mm.The maximum settlement occurs about 0.5 times of the excavation depth from the foundation pit.The maximum horizontal displacement of diaphragm wall occurs between 0.6 and 0.8 times of the depth of foundation pit,and the uplift value of foundation pit bottom reaches the maximum value,and the simulation result is 26.8mm.Comparing the numerical simulation results with the observation results,there are some differences between the two data,but the overall trend is more consistent.(5)By changing the distance between the buildings near the foundation pit and the distance between the surrounding underground pipelines and the foundation pit,the buried depth and the material modeling analysis,it is concluded that the building deformation is closely related to the distance from the foundation pit,the larger the elastic modulus of underground pipeline is,the smaller the deformation is.The closer to the foundation pit,the greater the pipeline deformation.The deeper the pipeline is buried,the smaller the deformation of the pipeline,and the closer the pipeline is to the surface,the easier it is to be damaged.