A Study On The Calculation Analysis Of Composite Supporting Structure Of Deep Foundation Pit And The Applications

Deep foundation pit is both a systematic engineering and a comprehensive geotechnical engineering characterized by complexity, for it not only covers the study of intensity and stability of soil mechanics as well as soil displacement and deformation, but also includes the interaction of soil and supporting structure. However, due to insufficient soil mechanics theory system, it is difficult to forecast the variance of the system only by means of mathematics and theoretical method. There may be a big gap between the theoretical results and actual situation because of the unexpected changes in the process of construction together with construction conditions, weather and the surroundings. Moreover, deep foundation pit is a product of multi-discipline knowledge, including soil mechanics, structure engineering, hydraulics and other related disciplines, which poses a great challenge for researchers.Based on the previous research, the paper applies the finite element calculation program ANSYS to build models of two dimensional soil-nailing and pile-anchor supporting and analyze their displacement, stress as well as stability. The paper:1) on the basis of existing deep foundation pit supporting patterns, discuss the selection of supporting structure under different geological conditions and engineering environments and compare the differing schemes.2) use finite element program of reduction coefficients to analyze the overall stability of soil-nailing supporting. Make an analysis of the mechanism of soil-nailing and anchor supporting and the influencing factors by drawing simulated cloud map of displacement and stress.3) establish two dimensional soil-nailing supporting model. Considering the elasto-plasticity of soil, the interraction between nail and soil, anchor and soil, as well as construction process, adopt reasonable grid division to exert forces on soil, nail, anchor and surface coordinatively and achieve deformation coordination. Summarize basic principles about stability, displacement and stress through the analysis of deformation of soil,nail and anchor. Suggestions are subsequently offered on the design of soil-nailing and anchor supporting. 4) design the supporting pattern for the deep foundation pit of Anhui Provincial Hospital through fully understanding of the geological conditions, the surrounding buildings and other related factors.