Study On Seismic Response And Simplified Analysis Method For Typical Transfer Subway Station Structures

As a country with many earthquakes,China has more than 70% of the major cities located in seismically active region.Thus,the seismic design and safety assessment of the urban infrastructure is an important project of urban development.The construction cost of urban underground rail transit is very expensive.It is extremely difficult to repair its damage once it occurs.Therefore,there is of great engineering significance and academic value for the seismic researches on the urban underground rail transit.Previous seismic researches mainly focused on the subway station with simple structural forms and formed comparatively mature design methods.In recent years,as the urban underground rail transit networks have grown more complex,there are more and more transfer subway stations with complex structural forms.The seismic responses of the complex subway stations are not only affected by the interactions between the structure and surrounding soils,but also by the interactions within the structures themselves.Few researches focused on this area in the past.Simple and effective seismic design theories and methods were lacking.Given the above,two typical transfer subway stations were studied in the paper,namely,cross node transfer and H-type short channel parallel transfer.The seismic response characteristics and seismic analysis method of two typical stations were discussed by theoretical analysis,shaking table model test,and finite element numerical simulation.It was expected to provide a reference for seismic researches on complex underground structures.The main work completed and the relevant conclusions were as follows:(1)A bidirectional plate model with idealized local forces was used in analytic derivations for the first time.The influence on the local force characteristics of the sidewall by the cross transfer zone of the cross-station was explored.Results showed that the influence range explored was basically within 3 times the height between floor.The internal force responses of the station structure beyond the range was consistent with that of the standard section.(2)The shaking table model test of the cross-station structure was carried out for the first time.The dynamic deformation laws and dynamic interactions between the structural models under earthquake were revealed.Results showed that the interactions between the structural models in two directions were influenced by their own structural forms.The influence by the cross transfer zone of the cross-station on the overall structure and the interactions between the structure and surrounding soils were basically within 1.5 times the structural width.The structural model was no longer affected by the cross transfer zone beyond the range.(3)The process of the shaking table test was accurately reproduced by numerical simulation,which proved the scientific effectiveness of the numerical simulation method.Then,a full-scale model of a one-layer cross-station was established.The influence by the cross transfer zone on the local force characteristics of the sidewall was explored again,which proved that theoretical solutions from the bidirectional plate model was reasonable.In addition,a full-scale model of a multilayer cross-station was established.The law of the interactions between the cross-station structures were explored in different aspects.Results showed that the key factor of the dynamic response characteristics of the crossstation was their own structural forms.The seismic weak link of the cross-station was the interior column of the bottom structure within the cross transfer zone and the crossconnection segment between two directional structures.The influence range of the cross transfer zone was basically consistent with that from measured results under different external conditions,which was within 1.5 times the structural width.When exceeded the range,the structural model was no longer affected by the cross transfer zone.(4)A three-dimensional quasi-static seismic analysis method for complex underground structures was proposed,which was applied to the cross transfer subway station.The theoretical derivation and the engineering example proved that the method proposed was rigorous in theory and practical in seismic analysis.(5)The finite element model of a parallel transfer subway station with H-type channel was established and the interactions between the structures was explored,which improved understanding of the seismic response law of the complex underground structures.Results showed that the influence range of the channel transfer zone on the overall structure was basically within 1.5 times the transfer channel's width,while the influence range of the interaction between two parallel stations was basically within twice the structural width.Then,a quasi-static seismic analysis method for the parallel transfer subway station with H-type channel was proposed.