| With the accelerating of urbanization construction in our country, the city buildings achieved a breakthrough on the number and size, less and less available land resources of city were caused, and people’s demand was still increasing, which required the urban construction to have vertical development, leading to more and more deep of the depth of the foundation pit, so deep foundation pit supporting structure will be more and more complex, and security requirements will be more and more high.In the special weak expansive soil strata, deep foundation pit supporting was more complex, and achieved the foundation pit engineering safe, economical and stability, this was a new challenge for the geotechnical workers.Currently it often cannot accurately grasp the characteristics of weak expansion in the design of foundation pit, it had a certain error for the selection of foundation pit supporting method, led to loss of foundation pit engineering safe and economical, which can not meet the requirements of modern society resource-saving.However, the security and economy were often contradictory in deep foundation pit engineering. Therefore, it was the right way to solve this problem to find a reasonable supporting scheme and optimum design.This paper first expounded the research status of foundation pit engineering and weak expansive soil both at home and abroad,and then illustrated the existing types of foundation pit supporting technology and application condition in China, and introduced SMW principle and applicable conditions.Combined with the characteristics of weak expansive soil in Huainan, SMW engineering was applied to study feasibility in a deep foundation pit.Research process was as follows:first, the deep foundation pit engineering geological environment was analyzed, and then it was a comparative analysis separately from the design and calculation, numerical simulation and comparative analysis, calculated the SMW applications was feasible in the weak expansive soil, and met the requirements of safety and economy.In the study of the weak expansive soil deep foundation pit supporting, through the design and calculation, numerical simulation and construction monitoring data, and got the following conclusions:(1)the displacement of the pile in increasing as the excavation depth deepening, the biggest displacement was produced in the upper of supporting pile,and the moved in deep foundation pit under the bottom of the pile deformation is small.(2) Tensile strength of the anchor cable were falling down the end. The more it closed anchor cable end, The faster the rate of Tensile stress decrease was, the tensile stress bore was close to zero at the end of the anchor cable.(3)Anchor cable was only affected by the tensile stress in the process of foundation pit excavation, and the tensile stress presented decreasing trend as the foundation pit excavation, the lower anchor cable construction led to stress variation in the upper anchor cable.In this paper,by means of the theoretical analysis,design calculation, construction monitoring and numerical simulation analysis method of combining in a weak expansive soil of deep foundation pit supporting engineering of Huainan, analyzed the deformation of deep foundation pits,as provided the reference of the SMW feasibility for the weak expansive soil deep foundation pit supporting engineering, at the same time,it provided a certain security for economy safety of the whole deep foundation pit engineering. |
