| The thesis mainly studies tunnel surrounding rock geothermal field and thermal insulation layer design parameters of Balangshan mountain tunnel which located at high and cold moutain region.The numerical simulation theoretical basis is thermal analysis.Through laboratory test, numerical simulation methods,the thesis simulates high cold moutain region tunnel surrounding rock geothermal filed and supplies proper thermal insulation layer design parameters to the project.The results consist of following aspests.(1) Making use of ANSYS software as a tool to simulate tunnel region initial geothermaltemperature field and supply boundary conditions to the excavated tunnel surrounding rock temperature field. The conclusion is that the tunnel surrouding rock below the surface3.2meter initial temperature is greater than0℃.The surrounding rock’s lowest temperature is4.6035℃,located at K97+730,and the highest temperature is15.254℃,located at K102+23.(2) Making use of rock temperature which measured in bore to check the reliability and the accuracy of the numerical simulation.The thesis comes to the conclusion that the numerical simulation has higher reliability and accuracy.(3)Building two dimensions transient calculating model to simulate the depth of frost penetration of the tunnel surouding rock which is apart from tunnel entrance10m.The conclusion is that the longer of the calculating time, the deeper of depth frost penetration.(4)For the security purpose,we select extreme minimum temperature and the longest calculating time30days as the load conditions and exert them in the thermal insulation layer design model.The calculating results show that when laying5cm alumina silicate fibre thermal insulation material in the sufface of the tunnel secondary lining, it can effectively protects the tunnel secondary lining and the tunnel surrounding rock from freezing. |
