Research On Optimal Support Scheme Of A Deep Foundation Pit In Kunming Peat Soil Area

The rapid development of the city has led to the rapid rise of the construction industry.Peat soil is widely distributed in the southwest region.More and more deep foundation pit projects are built in the peat soil area.How to choose an economical,reasonable,safe,reliable and fast construction foundation pit.The protection scheme has become an important topic in the deep foundation pit engineering in the peat soil area.Starting from the actual engineering of the peat soil area in Kunming,this paper first introduces the types of deep foundation pit supporting structures that have been common in recent years,analyzes the advantages,disadvantages and application scope of various supporting structures,according to the actual engineering geological and hydrological conditions and The evaluation and analysis of geological and hydrological conditions preliminarily select three alternative foundation pit support schemes.Then introduce the theory of foundation pit support scheme selection,and use the analytic hierarchy process and fuzzy comprehensive evaluation method to optimize the three primary selection foundation pit support schemes.Then,Midas/GTS software was used to build a model for the foundation pit support scheme,and finite element simulation analysis was performed to obtain the horizontal and vertical displacement and deformation cloud diagrams at different construction stages.Finally,in order to ensure the smooth progress of the deep foundation pit supporting structure,the monitoring requirements,technical quality requirements and other requirements in the construction process are expounded,which need to be strictly followed and implemented.The main research work and conclusions of this paper are as follows:(1)Analyze and compare common foundation pit support structures,optimize the three preliminary selected alternatives,build an evaluation system with four criterion layers and thirteen index layers,and use the analytic hierarchy process and fuzzy comprehensive evaluation method Optimal scoring was carried out,and the "double-row pile" support scheme with the highest score was taken as the optimal scheme.(2)Combining with the actual foundation pit engineering in Kunming peat soil area,it is divided into units I and II,and different structural details are designed for the optimal plan for different units.The support structure design of unit II is checked and calculated.(3)Use Midas/GTS software to carry out finite element simulation analysis on the support scheme of units I and II,determine the material parameters,and then carry out modeling.The safety feasibility of the double-row pile scheme is determined by comparing and analyzing the cloud map data.(4)According to the concrete double-row pile support scheme,the deformation monitoring requirements in the construction process of deep foundation pit engineering in Kunming peat soil area are proposed,and the actual monitoring data are analyzed and compared with the simulated value.Using Midas/GTS software simulation unit ⅱ to select different pile length,pile spacing,pile diameter and other parameters,analyze the influence of these parameters on the stress deformation of double-row pile retaining structure,and put forward suggestions for the design of double-row pile retaining structure in peat soil area.