| With the rapid development of Chinese economy,more and more city started construction of the subway,subway construction and development make a spurt of progress.Subway construction can’t do without excavation,excavation is can’t do without the foundation pit supporting,subway excavation involves various geotechnical mechanics and engineering,Improper supporting technology and Ineffective excavation measures may lead to surrounding rock deformation and other hazards,caused a significant safety hazard for surrounding buildings.Therefore,It’s a key of study to reduce the disturbance of surrounding soil in deep foundation pit excavation and minimize the deformation during excavation.Based on this,this paper based on reading a lot of literatures and summarizing the research results,taking a domestic subway station deep excavation project background,puts forward a design scheme of deep foundation pit,F-SPW software is used to check the envelope structure,the Midas-GTS software is used to simulate the excavation of the foundation pit and using time history analysis method to establish model analysis of the station.The main research contents and results are as follows:(1)The study introduces the research background and significance of the foundation pit support,and analyzes the characteristics and existing problems of the existing deep foundation pit support;(2)On the basis of reading a lot of literature,the paper analyzes the main types of deformation of foundation pit,factors affecting the deformation of foundation pit,calculation of earth pressure on retaining structure of foundation pit and introduces the requirements of seismic design of subway station;(3)Collects the general situation of the engineering and hydrogeological conditions and the surrounding environment conditions of a subway station in China,determines excavation method of foundation pit and the type of supporting structure,and gives the steps of the construction of subway station standard section;(4)Analyzes and calculates the retaining structure of deep foundation pit by F-SPW software,and Midas-GTS software is used to simulate the process of pit excavation,the results are in line with requirements;(5)Introduces the history analysis method,and taking the subway station as an example,establish the model by time history analysis method to analyse the maximum displacement value,the inter story displacement,the maximum internal force of the structure and the internal force and displacement of the standard section in different conditions,the results of numerical simulation show that the displacement difference between the roof and the floor,the inter story drift angle,the maximum bending moment,the maximum axial force and the maximum shear force,and the maximum axial compression ratio of the column meet the requirements.To sum up,this study has important theoretical significance and practical value for the design of similar foundation pit engineering drawing. |
