Study On Mechanical Damage Of Surrounding Rock Lining Structure Of Tunnel In High Temperature

With the progress of technology civilization and the sustainable development of transportation,as a very important traffic assistant tool,tunnel has been developed rapidly.However,with the pace of people's life is getting faster and faster,the driving speed become quicker and quicker,the traffic density of the tunnel is increases day by day.All of this leads to the frequency of many kinds of tunnel accidents which is increasing year by year.In all kinds of accidents in tunnel,the highest frequency and harm is fire.If high temperature fire broke out in the tunnel,in addition to the smoke choked to death,the temperature which produce at the high temperature fire is also very badly to the harm of tunnel,high temperature will lead to tunnel lining structure damage,this not only cause accident site personnel casualties,but also can cause a certain amount of economic loss and bad social influence.So,research on the mechanics damage law of tunnel lining structure under high temperature fire which can helps people to in-depth understand the influence of high temperature fire in tunnel and helps people to carry out the better repair work of the tunnel after fire.In this paper,the research focus on the effect of high temperature on mechanics properties of tunnel lining structure,the main research methods which used in this paper contains indoor test and ANSYS finite element numerical simulation.The mechanical damage laws of red sandstone and C30 concrete after high temperature were emphatically studied.The distribution law of temperature field and stress field of tunnel lining structure at high temperature were also emphatically studied.Through the above study,the main conclusions are as follows:(1)The effects of temperature on the mechanical properties of rock and concrete are similar,when the temperature in the range of 22??800?,as the temperature goes up,the compressive strength of both materials increases first and then decreases.When the temperature at 400?,both the compressive strength reached the maximum.(2)Through numerical simulation combined with the indoor experiment found that in two hours of tunnel fire,the temperature will only damage the tunnel lining concrete materials,it will not harm the surrounding rock structure of the tunnel.(3)Through the thermal-structural coupling analysis of the tunnel after high temperature fire,and based on the ANSYS finite element numerical simulation discovery that when fire broke out in the tunnel,the most vulnerable position is at the bottom of the tunnel lining wall and the arch foot.