The Monitoring Analysis And Numerical Simulation For Loess Deep Foundation Pit

Based on Xi'an subway station deep foundation pit in loess area,this article studys earth pressure and deformation law of retaining structure in urban subway station foundation pit by using the manner of theoretical analysis,field monitoring and numerical simulation method,for the future of deep excavation system optimization study in Xi'an to do some theoretical groundwork.The main jobs and conclusions are as follows:1.Through on-site analysis and collation of monitoring data,this article researches deep excavation earth pressure changes law of the loess areas and focus on the loess soil region of deep foundation of the relationship between pressure and time and the relationship between displacement.The results show that:loess also have a certain time variation,and the earth pressure's impact by the time and the displacement is in a dynamic equilibrium process.2.It Sums up the deformation control standards in different regions of the current. Through on-site analysis and collation of monitoring data,it focus on displacement of pile top,earth'settlement,strut axial forces,and pile displacement changes law.The results show that:loess deep foundation pit have small deformation and small impact to the surrounding environment because the loess' self-stability is very good.3.FEA numerical analysis method has been used to stimulate the excavation of construction process to study displacement changes law of the pile.The calculation results and the monitoring results were compared,results showed that:establishment of the model,parameter selection and calculation method are reasonable and calculation results can reflect the general law of the foundation deformation. 4.Tongji Venus deep excavation analysis and calculation software of retaining structure has been used to analyze the impact of embedment depth of pile,pile spacing, surface loading,the steel support spacing,steel support adding for pre-axial force to the foundation deformation,obtain these factors' impact extent to the deformation in the loess area.5.Subway station is a complex construction project.This article summarizes the key construction technologies of the subway station,including:pipeline protection technology of subway station construction in loess area and pile drilling technology in sand.These technologies will provide a very good reference for the construction of similar projects.