The Study Of Occlusal Piles Supporting System Of Deep Foundation Pit In Reclamation Area

Since the reform and opening up,especially in the last 10 years,China's economicdevelopment has made remarkable achievements.With the development of the economy,the people's demand for life is also increasing,one of which is the demand for the improvement of the living environment.As a result,the urban land is becoming more and more tense,make full use of underground space is more and more necessary.In the use of underground space,inevitably involves the foundation pit excavation,due to the requirement of urban construction,both in area and depth of foundation pit is at present larger and larger,and thus accident is rising.Foundation pit engineering is the foundation of the whole building engineering,spend more time and money.But the excavation of foundation pit is a very complicated process,influenced by various aspects of human,environmental and site differences in factors,need for targeted research based on a combination of different factors,and then expand the research from point to surface,eventually forming a set of complete system of foundation pit design that contains most factors.This paper,taking one station of dalian city metro line 2 deep foundation pit supporting engineering as an example,using lizheng software verified internal force and displacement of occlusal pile in foundation pit,verified the rationality of the design drawings;Using ABAQUS software to simulate foundation pit by finite element analysis and get the deformation of the support system after excavation,and concluded the law of foundation pit deformation in the process of excavation;Monitoring the data of foundation pit deformation,then compare the results of numerical calculation data and monitoring data,evaluate the rationality of ABAQUS analysis software for simulating excavation problems.put forward the general laws of deformation of the supporting system,provide theoretical support for the future similar excavation engineering.The process of the study is briefly described as follows:1.First of all,select typical sections(that is,comprehensively considering the depth of foundation pit excavation,the depth and thickness of each rock and soil,physical and mechanical properties of each rock and soil,groundwater conditions,and other factors,select the most unfavorable influence section on the safety of foundation pit excavation).obtain the initial stability analysis by putting the design parameters into the calculation software of Lizheng deep foundation pit.Get the variation of soil pressure,internal force anddisplacement of supporting structures under different excavation conditions.analyse its numerical value,and identify the safety of the design scheme.2.The occlusal pile supporting system is transformed into a two-dimensional plane strain structure system.Then use ABAQUS finite element analysis software to simulate the process of the excavation and supporting.obtain the changes of the stress and displacement of the excavation and the deformation of the supporting system,analyse its numerical value,and identify the safety of the design scheme.3.According to the above calculation results,optimize the design scheme: use the high pressure jet grouting pile to reinforce the weak soil layer at the bottom of the pit after the excavation of the third layers,so as to reduce the uplift of the bottom of the pit and the deformation of the supporting system.Put the reinforced parameters into the ABAQUS analysis software,and output the deformation of the bottom and supporting system after the reinforcement,and compare the results with the calculation results without the reinforcement measures,then obtain the theoretical basis for the design optimization results.4.Analyze the monitoring data of the surrounding ground settlement,the horizontal and vertical displacement of the supporting pile and the axial force of the supporting system during the excavation of the foundation pit,and compare the data with the theoretical calculation results,compare their similarities and differences,and analyze the reasons for the difference.Then evaluate the rationality of ABAQUS finite element analysis software for simulating excavation problems.