Study On Stress And Deformation Law Of Surrounding Rock Support Structure Of Super-section Subway Station

The construction of urban underground engineering has entered a period of rapid development due to the fact that urban traffic congestion becomes more and more serious with the increase of urban population and the expansion of city scale.Many subway stations,lines under the ancient buildings,highways,railways,rivers,residential areas,oil and gas pipelines,resulting in particularly complex construction environment.With the expansion of the city and the increasing demand for Metro stations,the section of metro stations is becoming larger and larger.Therefore,it is of great significance to study the stress and deformation law of surrounding rock support structure of super-large section Metro stations.Subway station construction methods can be generally divided into two categories:open cut method and hidden excavation method.Underground excavation is a method that does not dig the ground and uses underground excavation.Mine method and shield method are both underground excavation methods.Although the construction technology of urban tunnel and underground engineering by shallow-buried and undercut method is relatively mature,due to the uncertainty of engineering hydrogeological conditions and the complexity of construction environment,it makes underground engineering by shallow-buried and undercut method.In the process of construction,there are still many construction risks and many risk accidents.In this paper,Toutang Station of Chongqing Rail Transit Line 4 is taken as the research background.The station has a span of 26.4m,a height of 28.2m,a section area of 667m~2 and a depth of 20.0-32.4m.It belongs to the Shallow-buried metro station with super-large cross-section.From the stability and stress analysis of surrounding rock to the design of supporting structure,the actual construction of the tunnel with super-large cross-section is detailed.Detailed analysis and summary,in order to provide reference for domestic tunnel construction projects.The main conclusions of this paper are as follows:(1)Acoustic emission system and non-metallic ultrasonic detection system are used to test the P-wave velocity of rock and rock mass respectively.The surrounding rock of Toutang station is classified before and after excavation.The stress concentration is caused by the damage of rock mass and excavation disturbance caused by blasting construction,and the rock mass integrity coefficient decreases after excavation.(2)The surrounding rock deformation,vault settlement,surface subsidence,the anchoring force are monitored in construction method of reservation rock beam and pillars in model T.The Peck formula is used to analyze the vault settlement,ground settlement,and forecast.(4)By using the stress and deformation analysis of surrounding rock,the application of safe pressure dispersed anchor cable can effectively limit the deformation of rock mass,especially in the geology of bedding,which can effectively ensure the safe operation of the project.(3)Based on microseismic technology,the micro-rupture signal of surrounding rock of metro station construction is monitored,and it is concluded that the construction method of reserved T-shaped rock beam and rock column is suitable for the construction of super-large section shallow-buried Metro station.(4)Distribution laws of surrounding rock stress,deformation and stability coefficient are simulated and analyzed by using 3D-_finite element software,which provides theoretical reference for the study of surrounding rock deformation and stability law of super-large section Metro station.