An Analytical Solution For The Frost Heaving Force And Displacement Of A Noncircular Tunnel

With rapid economic development in China, the railway network extends from Northeast to Northwest China. Numerous tunnels are inevitably built in cold regions that experience frost damage. However, studies on the analytic solution of the stress and deformation for noncircular tunnels in cold regions are very limited. To solve this engineering problem and propose new theoretical insights for analysis and design, a novel noncircular solution is established in this paper. In this model, the infinite plane is divided into three parts, namely, the tunnel lining, frost heaving zone, and unfrozen surrounding rock. Then, the stress and displacement fields can be determined based on the continuity conditions of the three parts. Considering that part of the deformation of the rock mass occurs before the lining is applied, this release of the surrounding rock load is given through the support delay coefficient ?. The Zhegu Mountain tunnel, as a numerical simulation case, is introduced to verify the analytic solution, which shows good consistency between the two. The additional stress of frost heaving is distributed unevenly at different positions, threatening the safety of tunnel structures. The reason why the frost heaving force of the analytic solution is generally larger than that of the field monitoring data is also addressed.