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| Establishment and solution of a soil and nailing interaction model of slopes in seasonal frozen soil areas considering frost heaving effect |
| DONG Jianhua1，2，WU Xiaolei1，2，LIAN Bo1，2，ZHENG Yalin1，2 |
(1. Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province，Lanzhou University of Technology，Lanzhou，Gansu 730050，China；2. Western Engineering Research Center of Disaster Mitigation in Civil Engineering of Ministry
of Education，Lanzhou University of Technology，Lanzhou，Gansu 730050，China) |
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Abstract In order to study the distributions of shear stress and axial force along the length direction of soil nailing of slopes in cold regions considering frost heaving effect，in this paper，the movement law of the freezing front is discussed based on the heat transfer theory and the differential equation of solid-liquid two-phase coexistence，and the calculation formula of free frost heaving deformation of a slope in cold regions is further derived according to the formula of frost heaving rate. On this basis，regarding the supporting effect of soil nailing on slopes as shear distributed force along the length direction of soil nailing and considering the stiffness difference between the frozen layer and the unfrozen soil layer of a slope，the displacement analytical solution of any point on the interface of nail and soil interaction is derived by combining the stiffness layer method with Mindlin solution after coordinate transformation. Finally，Based on the displacement compatibility condition of soil and nailing interaction，the Riemann integral equation of the shear distribution force along the length direction of soil nail is established. The axial force distribution of soil nailing is obtained by using the compound trapezoidal integral formula of closed Newton-Cotes method and MATLAB software programming，and verified by comparing the numerical solutions and the measured values. In addition，the influence of the frost heaving rate and the initial water content on the shear stress and axial force distributions along the length direction of soil nailing is analyzed. The results show that the distribution of the axial force of soil nailing obtained by the developed coupling calculation method is basically consistent with the numerical simulation results and the measured values，indicating that the coupling calculation method is reasonable and feasible. It is also revealed that the distributions of the shear stress and the axial force along the length direction of soil nail conform to the neutral point theory，the axial force curve presents a parabola shape with small ends and large middle，and the maximum axial force appears at the position where the shear stress is zero. The influence of the frost heaving rate，the initial water content and the nailing length on the shear stress and the axial force along the length direction of soil nailing can not be ignored. The research results can provide a useful scientific reference for the design of soil nailing support structure of slopes in cold region under frost heaving condition.
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2022, Vol. 41 
