Foundation Pit Support And Precipitation Design Of Lanzhou City Rail Transit Line 2 Post And Telecommunications Building

In recent years,with the accelerating process of urbanization in our country,a large number of high-rise buildings emerge.The construction of urban metro makes the excavation project gradually appear deep,large and complex characteristics,the importance of the pit project is increasingly revealed.The form of foundation pit support has also evolved from the previous single form into a support system combining various support ways.However,due to the changing geological conditions and the complexity of underground structures,a large number of problems occur in the design,excavation,precipitation and water separation of the foundation pit project.It affects the stability of the foundation pit,leading to instability of the foundation pit supporting structure and other accidents.Pit instability will not only affect the duration,but also cause a lot of manpower,material and financial losses,and even affect the safety of the surrounding buildings.Therefore,in the design and construction of the foundation pit supporting structure,the geological conditions must be ascertained,reasonable design and calculation parameters should be selected,and a reasonable type of foundation pit supporting structure should be selected for the design and calculation of the foundation pit supporting structure.In this paper,Lanzhou Metro Line 2 Posts and Telecommunications Building Station pit engineering practice,through drilling and laboratory tests to study the strong weathered sandstone physical and mechanical parameters.It chooses the form of underground continuous wall support structure,designs and calculates the underground continuous wall support structure and foundation pit dewatering,and provides reasonable suggestions and suggestions for the construction of the foundation pit project.Through the research in this paper,the stratum conditions of the subway station construction area are revealed,and the strength and deformation parameters of the stratum are obtained,which provide the parameters for the subsequent calculation.Select the underground continuous wall as the foundation pit supporting structure and simulate the excavation steps to calculate the internal force of the structure such as the shear force,the bending moment and the displacement of the foundation pit retaining structure of the diaphragm wall.The geometrical parameters and reinforcement of diaphragm wall are calculated from the calculated data.Through the combination of drainage design and construction during the construction of surface and foundation drainage,effectively eliminate the impact of groundwater on the construction of the pit.At the same time,in order to ensure the safety of foundation pit during construction,the deformation of surrounding buildings and the internal force and deformation process of supporting structures themselves during construction are closely monitored to monitor the deformation of ground subsidence and ensure the construction safety.