Research On The Mechanical Properties Of Subway Tunnel Lining Under High Temperature

The emergence of metro effectively solve the urban traffic congestion.The subway has become the first choice of travel.Because the subway traffic increases sharply,but the safety measures is not improved.In the event of fire,high temperature will reduce the mechanical properties of the subway lining structure,which can lead to uneven deformation structure,structural internal force redistribution,and finally may more than load-bearing ultimate capacity of lining structure,leading to structural collapse.With the rapid development of subway in China,how to improve effectively the metro lining structure of fire resistance and high temperature in rapid accurate assessment after fire damage degree of the lining subway system has become one of the main direction of research in the future.This paper studies the metro lining structure in the fire damage and discusses the applicable to metro lining structure after fire detection evaluation methods.Put forward from the lining structure within the material properties to improve the fire resistance and how to strengthen the fire prevention of metro lining structure outside.Specific research contents include:(1)The fire scene for the subway lining structure system.(2)The lining structure under the fire of the section temperature field distribution;(3)The high temperature of lining section bearing capacity calculation method;Through literature research,this paper found that after high temperature fire,the subway segment lining structure changes obviously.With the temperature increasing,the physical and mechanical performance degradation of the segment is very obvious.The bearing capacity of lining segment is rapidly reduced.Through the analysis of tunnel fire happened,the fire temperature curve,the duration of the fire and the highest temperature presents a clear definition,and select the appropriate material thermal performance parameters,thus reasonable design fire scenario.According to the actual situation of boundary conditions to make reasonable assumptions,using ABAQUS software simulate the fire temperature lining segment of section temperature field distribution.The temperature field Simulated plugs in to the lining structure system,and the numerical simulation was carried out on the bearing capacity of lining structure under high temperature.The paper uses the method in which the lining segment section is divided into several equal parts.Through the temperature field,calculate the high temperature bearing capacity of lining section.The bearing capacity of lining section under normal temperature is compared with ABAQUS simulation,and whether the bearing capacity is satisfied with the safety requirement.Also in this paper,through literature research,this paper puts forward for subway fire evaluation methods and steps of lining system.