Study On Experiment And Numerical Simulation Of Subway Station Roof Multi-Hole Beams

With the development of society and people’s growing demand for traffic,subway trip is playing an increasingly important role in people’s daily lives,which can be described as "connecting the upper and lower",connecting the ground and underground passenger transportation hubs.Therefore,the safety and stability of its structure is particularly important.This thesis is based on the experimental research on the key components of a prefabricated subway station in Guangzhou,which is a beam with multiple holes in the roof of the subway station.The important pipelines inside the station are planned to pass through the holes in the beam.It not only has a beautiful structure,but also incearses the economic benefits.After the opening of the beam,the mechanical performance of the beam and the stability of the structure are related to the overall safety of the station.This thesis will conduct model tests on the corresponding places.The main research content and research results are as follows.(1)Baesd on the actual project of a prefabricated subway station in Guangzhou,the three-dimensional finite element model of the subway station is established by using Abaqus finite element software simulation analysis.Parameters are set to calculate and extract the internal force of the roof opening beam.And on this basis,a model test scheme with the scale of 1:2.5 is designed to carry out the mechanical performance test of the multi-hole beam on the roof of the subway station.The test includes static loading and low-cycle cyclic loading.(2)The results of the static loading test show that the failure process of the multi-hole beam is ductile failure.Before the failure of the specimen,the member has a large deformation and has obvious failure signs.The shear strength of the compression boom at the opening position is higher than that at other position,which is a reasonable failure mode.Under normal working conditions,the crack width of the multi-hole beam is small,the stress of steel bar is at a low level,and the reinforcing steel bar near the hole plays a role,and there is a certain degree of safety guarantee.Subsequently,the failure location appeared at the corner of the hole,and the concrete at the corner of the hole gradually spalled.With the development of the plastic deformation of the tensile steel bar,the test beam was crushed and destroyed because the fiber at the edge of the concrete in the compression zone reached the ultimate compressive strain.(3)The results of the low-cycle cyclic loading test show that the failure mode is ductile failure.The steel bar reached yield first,and then the concrete was crushed and destroyed at the loading point,showing good ductility.In terms of the fullness of the hysteretic curve,the whole curve of the multi-hole beam was inverted S-shape during the loading process,and the fullness was relatively low,indicating that the opening of the beam belly had an impact on the seismic performance of the beam itself,but the reinforcement in the hole area effectively inhibited the generation and development of cracks around the hole,and the integrity of the beam hadn’t been weakened too much.(4)The three-dimensional numerical model of multi-hole beam static loading and low-cycle cyclic loading was established by Abaqus software.The thesis compared the bearing capacity and failure mode of the finite element,static loading and low-cycle cyclic loading test results.The two were generally in good agreement,and the development trend was basically the same,which indicated that the numerical results have a certain reference and reliability.On this basis,a parametric analysis of concrete strength grade and reinforcement strength was carried out.