Enclosure Pile Of Deformation Monitoring And FLAC Simulation Of Subway Line14Chaoyang Park Station In Beijing

Subway station construction mainly by open-digging, deformation control ofopen-digging deep foundation pit excavation is the key technique of construction.Reasonable design of the retaining structure is the main ways of deep foundation pitexcavation deformation control.On subway station deep foundation pit deformation mechanism are analyzed,summarized the main factors of the influence of deep foundation pit deformation arepit scale, the retaining structure form, construction organization, soil character,groundwater and so on, a reasonable choice of design scheme is to ensure thefoundation pit construction safety.In this paper, the enclosure structure of subway station deep foundation pitengineering use the bored pile+steel supporting mode. Through the monitoring on thehorizontal displacement of the pile body and the steel support axial force monitoring,focusing on analysis of retaining pile deformation and steel support axial forcevariation regularity of ZQT-10and ZQT-19monitoring point. Feedback thedeformation of enclosure structure at excavation stage in time, provide the referencefor the construction reasonable and deep foundation pit safe and stable. Monitoringdata show, the horizontal displacement of the pile body follow certain regularity, piletop displacement is the maximum at excavation initial stage, steel support effect theobvious inhibitory action, the final deformation is bow, the maximum displacementappear in near the middle of excavation depth. Because of the supporting notimmediately and super excavation can also aggravate enclosure pile deformation.With the development of computer technology, numerical simulation apply inengineering widely, the FLAC3D finite difference software using explicit Lagrangealgorithm and the mixed discrete method, without the formation of stiffness matrix, avery small memory space will be able to solve a wide range of three-dimensionalgeotechnical engineering problems. Using FLAC3D software for calculatingsimulation. The deep foundation pit excavation use step by step in the simulation process, analyze the displacement and stress at different depths of surrounding soil andenclosure structure. The whole process of simulation in four steps, any step isexcavation prior to supporting, obtain the soil horizontal, vertical displacement andenclosure structure the first, third principal stress at every steps. Comparative analyzethe numerical simulate results and monitoring results, obtain the deformation rules ofdeep excavation pit, provide reference to verifying the rationality of surveillanceprogram, ensuring construction safety and optimizing enclosure structure design.