Research On Lining Structure Damage Of Highway Tunnels Under High Temperature Fire

Highway tunnel fires, with the feature of high temperature, rapid rising rate and low heatdissipation, will not only cause heavy casualties and damage, but also destroy tunnelstructure and facilities if occured. Therefore, it is of great significance to study thetemperature field and thermal stress of lining on fire condition to evaluate the structure’ssafety and damage degree.The main content of this thesis is as follows:(1) The distribution of temperature field inside the tunnel under different fire intensitiesand ventilation velocities is acquired by the fluid simulation software PHOENICS. Thentemperature-time curves of tunnel vaults in each tunnel section, which is chosen according todifferent distance to the fire source, are established as thermal loads of lining temperaturefield simulation.(2) By choosing temperature-dependent thermal parameters and proper boundaryconditions on the bases of heat transfer theory, temperature fields of tunnel composite liningsin different fire intensity and tunnel sections are simulated through large-scale finite elementanalysis software ANSYS to study its temperature distribution law.(3) Based on the above temperature fields, thermal stress fields of the second lining aresimulated through ground-structure method, which aims at studying the lining’s thermalstress field distribution under thermal insulation condition and the time and depth of lininginjury under certain safety factor.(4) Methods of detecting and evaluating the lining structure damage after tunnel fire andmethods to improve the lining’s fire resistance performance are summarized on the bases ofprevious experiment.