Study On The Character Of The Subway Station Foundation Pit Constructed By Open Surface Method In Soft Soil

Since the21st century, China’s society and economy has been in rapid developmentstage. The urbanization advancement speeding up unceasingly has brought seriouscontradiction between the urban population growth and the infrastructure. To solveurban traffic congestion, many cities began the construction of subway projects inaround China. In the process of subway construction, excavation disturbed thesurrounding formation, which caused the deformation of supporting structure, thesurface settlement, furthermore to bring influence of different degree to the surroundingbuildings, underground structures and crisscrossed pipeline. Particularly in the southeastcoastal areas of our country, engineering accidents occurred frequency due to the softsoil, which caused serious damage.Soft soil is short for soft clay. In our country, soft soil is mainly distributed insoutheast coastal areas. It’s characterized by high natural water content, large void ratio,low shear strength, high compressibility, and permeability, weak. Currently urbanunderground space developed rapidly in soft soil area of china. It brings a series ofgeotechnical environmental engineering problems in the construction process ofunderground subway station and tunnel interval, due to the soil characteristics of thesoft soil, which makes serious impact on the subway construction safety and people’snormal life.In view of the problems in the construction of subway station deep foundation pitin soft soil area, this paper combined with the actual engineering monitoring data,analysis the development process and the law of the stress and deformation of deepfoundation pit retaining structure and surrounding ground settlement and buildingsettlement, etc. Analyze the strength characteristics of soil mass with the stress path testunder different consolidation conditions. Set up a simplified calculation model of deepfoundation pit by finite element simulation, which consider the construction step.Research the stress and deformation characteristics of the retaining structure, and thedeformation characteristics of soil. It will offer reference to further improve subwaystation deep foundation pit construction design theory and design method in soft soilareas, which will promote our country great application and development ofunderground engineering security risk management system.