Study On Deformation Of Foundation Pit Under Asymmetric Load

With the rapid development of urban construction, the surroundings of subway station excavation pit are often complex, it is important that study on deformation mechanism of foundation excavation in the complex surrounding environment. Asymmetric excavation not only has the characteristics of general excavation but also has the characteristics of generally excavation not have. This paper relying on 6th air shaft of Hefei South Station, studying the deformation research when the environment is not different on both sides of excavation, doing the following work:(1)By elastic foundation beam deflection differential equation, consider the interaction between the envelope and support system, application to Finite Difference Method, obtained internal forces and deformations of envelope and establish excavation pit calculation model under different environments.(2)In this paper, the research object is 6th air shaft of Hefei South Station. Analysis the influence of station deep excavation to horizontal displacement of pile and axial force of support system as well as the change of surrounding environment under asymmetric loading, measured data indicate that the envelope will have a greater impact under asymmetric loading, close to overload side retaining structure deformation greater than the side away from the overload, away from the side of the envelope will have a reverse displacement. Excavation has a great influence on the axial force of the layer support system, the impact on the level of the support shaft force decreases, while the upper support shaft force change is very small.(3)Introduction of finite difference software FLAC3 D, established the numerical simulation model of 6th Air Shaft, numerical simulation analysis of asymmetric excavation pile lateral deformation and surface subsidence around, and the simulation results are compared with the measured data, the results showed that the numerical simulation and experimental data is consistent, numerical simulation can reflect asymmetric deformation excavation.(4)Basis on the model of 6th Air Shaft, used FLAC3 D numerical simulation the deformation of foundation pit structure when load size or load distance change, by comparing the numerical simulation, conclusion that the load change have a greater impact to pile deformation, when changing the load distance, the pile deformation also changed greatly. Pit will have overall directional displacement under asymmetric loading.