Study On Flexural Behavior Of Steel Tube Slab Structure During Subsurface Excavation

The traditional pipe-roofing method is based on the pipe jacking individual,pipe is just connected latch fastener and form a holistic pipe-roofing structure,then excavation soil to set up temporary support,finally the main structure is constructed.Although The traditional pipe-roofing Method can reduce the impact on the surface deformation during excavation,due to the connection between the pipe,it leads that the overall lateral stiffness is very weak.When soil is excavated,you need to set up multi-channel temporary support to ensure that the overall structure is stable,cumbersome construction support system increases complexity and risk of construction.However,steel tube slab structure improve the shortcomings of the traditional pipe-roofing structure,the adjacent pipe is connected with flange plate,reinforced concrete to increase its lateral stiffness and flexural capacity.In this paper,Relying on Line 9 of aoti Station of Shenyang Metro,this paper analyses the failure process,ultimate capacity,lateral stiffness and ductility of steel tube slab structure by laboratory model test,full-scale tests and numerical analysis to find the key factor.This paper analyses effect of ultimate capacity and ductility of steel tube slab structure on the spacing between the pipes by concentrated load tests.The experimental results indicates that the spacing between the pipes has a limited effected on the flexural capacity of STS structure,but effectively improved the ductility of STS structure.This paper analyses effect of ultimate capacity and ductility of steel tube slab structure on continuous bolts by symmetrical load tests.The experimental results indicates that continuous bolts has a limited effected on the flexural capacity and ductility of STS structure.This paper analyses flexural behavior of steel tube slab full scale structure by concenttated load tests.The experimental results are reaemble to steel tube slab model structure.The result indicates that stuy on steel tube slab model structure is reasonable and valuable.This paper stuy effect of ultimate capacity,lateral stiffness and ductility of steel tube slab structure with welding of flange plate,steel thickness,flange thickness,bolt diameter,reinforcement ratio,flange distance by numerical analysis.The results indicates:welding of upper flange plate has a observably effect on the flexural capacity and lateral stiffness of STS structure;steel thickness has a littlt effect on the flexural capacity of STS structure,but effectively improved lateral stiffness and ductility of STS structure;flange thickness has a more effected on the flexural capacity,lateral stiffness and ductility of STS structure;welding of bottom flange plate,bolt diameter,reinforcement ratio have little enhanced on the flexural capacity,lateral stiffness and ductility of STS structure;flange distance has a notably effect on the flexural capacity and ductility of STS structure,but have little enhanced on the lateral stiffness.