Analysis Of Deformation Control Of Deep Foundation Pit In Two Intersection

The safety and stability of deep foundation pit support structure in urban rail transit station is an important part of the research and design of construction and environmental safety.At the same time,the foundation pit project is developing towards a deeper,wider and larger direction,and the surrounding environment of the foundation pit is becoming more and more complex.This is a higher requirement for the safety and stability of the foundation pit,so the deformation control of the support structure becomes the leading factor of the design,construction and monitoring of deep foundation pit.In this paper,based on two crossroads chongqing rail transit station deep foundation pit engineering,using theoretical analysis,numerical simulation and measured data with simulated data the method of contrast analysis on the deep foundation pit deformation is studied.The main research contents and conclusions are as follows:(1)firstly,according to the ground deformation characteristics of deep foundation pit excavation in the soil-rock composite area,the deflection distribution function is used to analyze the measured settlement curve around the deep foundation pit,a simplified method for estimating the ground settlement suitable for this project is given,and the ground settlement value around the pit is calculated by using the simplified method.The calculated settlement value is in good agreement with the simulated value,which verifies the correctness of the model.(2)Secondly,combining with the deep foundation pit project of Chongqing intersection,MIDAS / GTS finite element software is used to analyze the stability of the foundation pit,and the horizontal displacement of retaining wall,axial force of anchor rod,ground settlement of foundation pit,foundation and structure of building are analyzed to obtain its deformation law.Secondly,the design simulates and compares the increase of excavation step distance with it,and draws a conclusion that the setting of excavation step distance can effectively control the deformation of foundation pit.Finally,the influence of overburden thickness of 3m,5m and 7m on the surface subsidence is simulated and analyzed.(3)through collecting,sorting out and analyzing the comparison and analysis between the measured data and the simulated data,it is concluded that the measured data are consistent with the simulated data.The correctness of the model is verified.Finally,through theoretical analysis,it is known that the construction is the stage of foundation pit deformation generation and development.in order to control the foundation pit deformation,we must start with the source of deformation and the process of deformation development.Therefore,this paper finally discusses the selection of excavation methods and the control measures of construction technology to the deformation of deep foundation pit during the construction process.