| The BaLang Mountain tunnel is an important part of the No.303provincial highway of Sichuan province and is located in cold region with high altitude. In this thesis some related reference values and the theoretical basis for anti-freezing layers design of this tunnel are presented. Therefore, the reasonable numerical models to study the changes and distribution regularity of the rock field temperature of the tunnel considering seepage were established. In this process, great amounts of data from tunnel region were collected by field measurement method, including joint parameters, air temperatures, and earth temperatures. Different approaches were used to establish models with a combination of field measurement method, numerical analysis method and theoretical analysis method. The research contents of this thesis show as follows:(1) The seepage field model of jointed rock mass for numerical simulation is established. The permeability coefficient used in the model is determined by the further calculation results of the joint parameters which are obtained through field measurement in the region of the tunnel. The seepage velocity of water in the rock mass is provided by numerical simulation results, it is a necessary parameter for the model of rock field temperature considering seepage. Besides, through the numerical simulation results, the F1fault fractured zone, Jiajin mountain syncline and Meixing town anticline are predicted as the larger water inflow zones. This result is verified during the actual construction.(2) The numerical simulation models are designed for rock temperature field of tunnel in the nature and excavated stage, comprehensively considering the influence of tunnel ventilation and fissure water seepage. According to the simulation results, the anti-freezing length reference values of entrance and exit of the tunnel are considered of550meters and600meters respectively.(3) The surrounding rock temperatures and the air temperatures of the tunnel entrance were measured during the construction stage of the tunnel. To verify the validity of the numerical simulation method used to study the rock field temperature, the rock temperatures measured above are used for a comparison with the rock temperatures got by numerical simulation method under the same working condition. The results show the reasonableness and reliability of the numerical simulation method used in this thesis. Consequently, the reference values of the anti-freezing layers design are available to the project. |
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