Study On The Thermal Damage Law Of Tunnel Lining Structure On Fire Disaster

Under the background of large-scale development of underground spacestructure, as the speed and density increasing of traffic and tunnel mileage increasing,the number and frequency of all kinds of tunnel accident also increases accordingly.Among them, the fire frequency is high on the biggest disaster of all, In addition tothe smoke choked the people, the structural damage even collapse under the hightemperature is one of the reasons causing casualties, but also the main cause of directand indirect economic losses, so the study of fire tunnel lining temperaturedistribution and damage characteristics is of great significance on the in-depthunderstanding of fire response of lining structure and the fire resistance performance.And to provide guidance for the health monitoring of tunnel structureThe main body of this study is the tunnel lining structure under high temperaturefire, using the numerical simulation as the main research means, the paper analyzesthe research on the mechanical properties and stability of the tunnel lining structureshape, lining concrete strength grade, different fire scene etc, the main researchcontents include the following aspects:(1) The analysis of the general mechanical characteristics and damage law oftunnel lining structure under high temperature, it is concluded that the length of timeof the fire and the fire size directly affect the distribution of the lining structuretemperature,then I fit out the damage curve;(2) Considering the influence law of temperature and stress at the aspect of thetunnel cross section shape, the strength grade of concrete and the time on fire, get thefire time as the main factors affecting lining temperature and displacement, the tunnelcross section shape and concrete strength grade for the secondary factor;(3) The simulation analysis of temperature distribution and dynamic failurecharacteristics of lining structure under the action of fire protection layer, end up withthat the lower the thermal conductivity of fire protection layer, the better of thethermal insulating effect;(4) Using the finite element software to do the analysis of engineering example,and compared with the results of the example，to get the feasibility and reliability offire simulation by finite element software.