Supporting Design And Numerical Simulation Analysis Of Deep Foundation Pit In Suning Plaza Of Donghu District,Nanchan

At present,urban buildings are becoming denser and denser,and the construction space of deep foundation pit engineering is becoming more and more limited.The deep foundation pit project must not only ensure the safety of the foundation pit itself,but also ensure the safety of the buildings,pipelines,roads,etc..Therefore,the requirements for deep foundation pit engineering are getting higher and higher.For the analysis of the deformation and stability of deep foundation pits,it is indispensable to study the changes of stress,displacement,internal force,etc.during the construction of deep foundation pits.This paper takes the deep foundation pit project of Suning Plaza Project in Donghu District,Nanchang City as the background,and comprehensively analyzes the supporting scheme in the design of the foundation pit project based on the geological characteristics of Donghu District in Nanchang City and the surrounding environment of the foundation pit,and then combines The actual construction process of excavation and support of the foundation pit was carried out by using the rationalized deep foundation pit software and MIDASGTS software to carry out the finite element of the supporting scheme of the reinforced concrete and steel combination internal support system and row pile support for the foundation pit Numerical simulation analysis,calculation and analysis of the soil stress and displacement of the foundation pit,the displacement,bending moment and axial force of the supporting beam.And compared with the monitoring data in the actual construction process.The following main conclusions are drawn:(1)Reinforced concrete internal support is significantly superior to section steel internal support in terms of the role of support.The internal rigidity of the section steel is small and the deformation is large.(2)In the internal support system of reinforced concrete and section steel combination,the maximum axial force occurs on the reinforced concrete support beam with the largest section of the lowest layer.The maximum bending moment occurs at the part of the lowest layer where the reinforced concrete support beam with the maximum axial force(section)comes into contact with the pile.(3)With the increasing depth of excavation,due to unloading,the cumulative displacement caused by deformation of the foundation pit under the stress of the surrounding soil will continue to increase.A reasonable supporting structure can effectively control the deformation of the foundation pit.(4)During the excavation process,there was no obvious uplift at the bottom of the foundation pit,and the castinplace pile played an important role in preventing the uplift of the foundation pit.At the same time,better soil geology also plays a role.(5)The numerical simulation of the deep foundation pit of the Suning Plaza project in Donghu District,Nanchang through Midas/Gts software shows that the design of the supporting system using bored piles and internal supports by incremental calculation is in line with the design requirements.(6)The research analyzes: the parabola principle of the horizontal displacement line of the pile,the scientific principle of uplift at the bottom of the foundation pit,and the principle of stress distribution at the bottom of the foundation pit.From the mechanics,I found the principle that produced these phenomena.The deep foundation pit of the Suning Plaza project in Donghu District,Nanchang is a common deep foundation pit in Nanchang.The calculation and numerical simulation results of the foundation pit support design scheme in this paper have certain reference and reference significance for the foundation pit support of similar projects.