Stability behavior of a reservoir soil bank slope under freeze-thaw cycles in cold regions

Abstract

The instability of irrigation reservoir bank slopes in cold regions has seriously affected the benign development of irrigation areas and agricultural production in recent years. To predict and evaluate the slope failure caused by freeze-thaw cycles, a two-dimensional numerical model of thermo-hydro-mechanical multi physical fields of a reservoir soil bank slope is established based on field investigations, laboratory tests and prototype observations. The relationship between the sliding surface temperature and the soil mechanical parameters is proposed by a secondary development program. The generation of the cracks on the bank slope top is explained from the viewpoint of temperature. The hydrothermal changing process of the bank slope under the external temperature is analyzed and compared with the measured data. The long-term degradation process of the soil bank slope under freeze-thaw cycles is studied, and the evolution law of its safety factors with the hydrothermal variation at the sliding surface is quantitatively revealed. The results show that the freeze-thaw cycles have an obvious accelerating effect on the soil bank slope instability, and the safety factor is decreased by 10.43% after 5 freeze-thaw cycles, which directly leads to the bank slope failure