Stability Analysis Of Composite Supporting Structure System On Soft Soil Deep Foundation Pit

Soil Mixing Wall(SMW) pile with rotary jet grouting pile anchor is a kind of economical supporting form that is able to satisfy the building control condition. In recent years, although it has been developed slowly in the western areas, this design method and construction technology is not fully mature. Thus, it is worthy of attention that if the SMW pile with rotary jet grouting pile anchor type can be successfully used in each area of the foundation pit support system. This paper is based on the data of “Jiaxing City Plaza project of geotechnical engineering”, with the principal of "safety, economy, ease of construction”, multiple comprehensive consideration, reasonable design scheme of foundation pit, and carefully selecting parameters. Besides, the finite element software is applied to stimulate the excavation of the whole excavation support construction process. Moreover, this paper verifies the issue that if the design scheme ideal can be under control through the comparison of construction monitoring data. The main contents of this research are as follows:1. According to the site investigation and survey data, this essay will analyze the engineering geological conditions, hydrogeological conditions, climate conditions, and the design parameters of foundation pit support will be determined.2. On the bases of actual situations of the project and site characteristics of the environment around, this research selects SMW pile jet anchor pile supported foundation pit supporting scheme to design the foundation pit supporting structure, and puts forward to the excavation and dewatering and drainage measures.3. With the selection of the foundation pit supporting structure, this paper will design the foundation pit-monitoring program, including the excavation peripheral and the soil displacement, the supporting structure internal force monitoring point layout, the monitoring method, the early warning measure and the monitoring technical request.4. Through the collation of foundation pit monitoring data, this research is going to analyze the excavation process of the displacement of deep soil, foundation pit surrounding roads pipeline displacement, foundation pit surrounding buildings settlement, the pit against the variation of the horizontal and vertical displacement and internal force of supporting structure. Besides, the foundation pit support design and construction scheme optimization will be given.5.With the finite element software to process numerical simulation of the foundation pit engineering, this paper focuses on the analysis of foundation pit surrounding the displacement of deep soil, deformation of surrounding buildings, pipeline settlement, support structure variation regularity of the internal forces. Meanwhile, this will be compared with the actual monitoring data to comprehensively evaluate the rationality and reliability of foundation pit composite support structure.