Calculation And Anlysis Of The Tunnle Lining's Thermal Stress Field Under High Temperature

This paper mainly discusses the tunnel lining's thermal stress field under the high temperature and analysis the change about lining stress field.Firstly, considering the high temperature problem, this paper details the process of the heat condution and according to the related condition and elastic-plastic theory bulds the differential equations of the heat condution and the boundary conditions and get the calculation formula of the temperature stress.Secondly, according to the relevant basic theory determined the calculation formula of thermodynamic parameters of the heat condution and bases on the differential equation use the difference method to get the calculation formula the temperature and interface between the linling and surrounding rock's calculation formulas.Finally, according to the current theory, obtained the model of the thermal stress field of the high temperature tunnel lining,compiled the calculation program and analysis the influnce by the relevant parameters of lining's stress field under the high temperature.This paper calculated four cases of temperature stress as follows:80℃,100℃,150℃and 200℃.The calculation of the example shows that under the high temperature, there is temperature gradient between soil and the internal of the tunnel.It will produce large stress in the internal of the lining and large tensile stress on the surface of the lining and may produce, temperature gradient will cause large surface crack or shrinkage crack in the concrete,which will brings serious harm to the lining structure and did a prospect for the further research.