Research On Design Method Of Primary Support Structure Of High Ground Temperature Tunnel Based On Thermodynamic Coupling Effect

With the development of China’s infrastructure construction,the scale of tunnel construction ushered in a rapid growth,especially in the western region of China,tunnel construction is in full swing.Due to the special geological conditions in western China,the design and construction of long and deep buried tunnels has increased greatly,which makes us have to face more and more geological disasters in the construction of tunnels,among which the high ground temperature environment has become more and more common.The high ground temperature environment brings great challenges to the construction,operation and maintenance of the tunnel.Under the high ground temperature environment,the high temperature in the tunnel will not only deteriorate the construction environment,but also bring great hidden dangers to the safety of the site construction personnel and the supporting structure.Therefore,it is very important to study high temperature tunnel.In this paper,by means of data investigation,numerical simulation,theoretical analysis and field measurement,the surrounding rock and initial support shotcrete of high temperature tunnel under thermodynamic coupling effect are studied and analyzed,and the main research results are as follows :(1)By means of numerical simulation,the influence law of surrounding rock grade and tunnel height-span ratio on surrounding rock temperature field is revealed,and the size and distribution characteristics of the disturbance range of surrounding rock temperature field under the influence of different initial surrounding rock temperature and cave shape are proved.(2)Using numerical simulation method,the influence law of different initial surrounding rock temperature and tunnel height to span ratio on surrounding rock pressure is studied.The modified formula of vertical uniform load calculation under different height to span ratio in this paper is given,and the variation law between lateral pressure coefficient and span is proved.(3)Determine the different grade of surrounding rock and tunnel depth-span ratio under the initial supporting structure,the change rule of temperature field is analyzed under the high temperature environment temperature and the initial supporting structure different positions inside and outside temperature difference changes along with the grade of surrounding rock and the depth-span ratio on the initial supporting structure influence law of the different parts of the inside and outside temperature difference.(4)With the method of theoretical derivation and field measurement,the high temperature tunnel primary support structure considering the comprehensive effect of surrounding rock pressure and the temperature additional stress,high temperature tunnel primary support of mechanics analysis model is established and the stress of analytic formula,build the thermodynamic coupling effect under tunnel primary support structure design method.The above research results can provide a certain reference for the subsequent design of initial support structure of high temperature tunnel.