Analysis of Frost Heaving Force in Seasonal Frost Region Tunnels: A Case Study of the Xiangyang Tunnel in China

Frost damage in seasonally frozen regions is a primary factor affecting tunnel safety, with frost heaving forces being the main external cause. Therefore, analyzing and calculating the distribution and magnitude of frost heaving forces on surrounding rock is essential for addressing frost damage in tunnels. When the frost heaving force exceeds the design strength, it can lead to the cracking of the lining concrete and a reduction in the tunnel's load-bearing capacity and support stability, posing serious safety risks during construction and operation. This paper is based on the Xiangyang Tunnel project and is grounded in elasticity theory for deriving the frost heaving force formula. Utilizing the von Mises criterion, it employs finite element software to perform thermal-structural coupling analysis, which provides insights into the temperature distribution within the tunnel and the stress distribution patterns of both the lining and the surrounding rock under the influence of frost heaving forces. In the shallow-buried section of the Xiangyang Tunnel, the maximum frost heaving force on the lining is concentrated at the junction of the arch and the base slab. In the deeply buried sections, the distribution of the frost heaving force in the lining is relatively uniform. In contrast, the surrounding rock's frost heaving force distribution follows a layered pattern from the inside out. Beyond a burial depth of 7 meters, the lining and surrounding rock frost heaving forces gradually decrease, approaching a constant value.