Authors:
Wangtao Jiang; Haiqiang Jiang;
Abstract:
The surrounding rock and lining of cold-region tunnel is always destroyed due to the frost heaving force, that seriously threatens the safety and stability for cold-region tunnel. Although many achievements of frost heave force model have been obtained, there are two factors have been ignored, such factors as in-situ stress and freeze-thaw cycles. Therefore, solving this issue is extremely important. Firstly, the calculation mechanical model of cold-region tunnel is established, and the expression of frost heaving force considering frost heaving effect and in-situ stress is derived on basis of elastic theory. Secondly, the relationship between the elastic modulus of surrounding rock and the number of freeze-thaw cycles was fitted through the experimental data, and the calculation formula of frost heaving rate considering the porosity change of rock damage after Nth freeze-thaw cycles is derived. Finally, the calculation method of frost heaving force considering the in-situ stress and the freeze-thaw cycles is proposed. The example analysis results show that frost heaving ratio and frost heaving force gradually increase with freeze-thaw cycles, and they eventually are subjected to a steady value. Simultaneously, the frost heaving force acting on lining increases with the in-situ stress, so it is necessary to apply insulation and antifreeze measures to the tunnel in cold regions.
Keywords:
frost heaving force; cold-region tunnel; freeze-thaw cycles; analytical solution; zero frost heave displacement