The Study Of Deformation Characteristics Of Pit In Pit In Soft Soil

Foundation pit engineering in urban basic construction project in our country has played a crucial role, with the rapid development of towns, the lower part structure, the foundation of the underground space and urban high-rise structure part of the development result in better utilization of underground space.Conventional represents means sump pit pit(well),such as foundation, the underground elevator shaft equipment belong to local parts of the excavation depth is more than a excavation depth. In this article is to research the pit pit: to meet the requirements of structural design of the construction of the special function, in the excavation of large foundation pit,the excavation again a small independent structure and function of internal foundation pit. Now the research of the pit pit technology is less and there is no corresponding design specification, but often appear on the actual engineering are mostly from experience design. The engineering accidents occur and the waste of resources.Thus, the importance of pit pit in engineering and the difficulty, it needs us to continue to explore.This paper set up a file in a pit pit engineering examples as the research object, c?? after the application of foundation pit precipitation value supporting design, compared with the original design in the engineering cost.And using the finite element software abaqus finite element analysis for this project, a two-dimensional model is established to simulate the excavation process, the analysis of the pit pit excavation and normal excavation of the difference.And compared with the actual engineering monitoring data analysis, the feasibility and applicability of simulation, and then through the simulation analysis of further research.C?? before and after the contrast analysis of the precipitation, the change of value, inside the hole pile length, distance between inside and outside the pit and the several aspects such as the presence of support within the pit for this paper.By sampling the soil shear strength experiment was carried out before and after the foundation pit precipitation c, ? value analysis, soil c? ? after precipitation value increase lead to shear strength of soil increased, pile after the active earth pressure(load) to reduce, pile devices for passive earth pressure increases(resistance), reduce the deformation of retaining structure and improve the stability; In foundation pit design, application of precipitation after c?? design saves the project cost, value;With the increase of two hole spacing, with the reduce of supporting structure deformation and the change is small, but the corresponding deformation of through calculation, the foundation pit in two excavation span is about 13 m when is critical point; Struts have played an important role in resistance to deformation, internal support can only control level to the deformation, the vertical displacement effect.