基于离散元法的干湿循环下膨胀土边坡稳定性研究

Hao Wang, Yejiao Wang * and Fujie Jin

School of Mechanics and Engineering Science, Shanghai University, Shanghai 200444, China

Abstract: The swelling-shrinkage behavior of expansive soils under climate changes will cause the crack development, which can be destructive of expansive soil slopes. This study investigated the effect of drying/wetting cycles on the stability of an expansive soil slope using the discrete element method (DEM), in consideration of the crack development induced by climate changes. The strength reduction method was adopted in the DEM calculations, which was coupled with the unsaturated seepage analysis given by the finite element method. The slope stability and the failure model of the slope after different times of wetting–drying cycles were analyzed, and the results were compared with those calculated by the limit equilibrium method and the finite element method. The results indicated that the failure pattern of the expansive soil slope was strongly influenced by the wetting–drying cycles. A shallow sliding surface of the expansive soil slope occurred after several wetting–drying cycles. Similarly, the safety factor of the expansive soil slope decreased gradually with the wetting–drying cycles. Considering the cracks’ evolution inside the expansive soil slope from the drying/wetting cycles, a shallower sliding surface with a smaller safety factor was obtained from the strength reduction method of the DEM, in comparison with the two conventional methods of the Limit equilibrium method and finite element method. Therefore, cracks play an essential role in the expansive soil slope stability. The strength reduction method of the DEM, which considers the cracks’ evolution during drying/wetting cycles, is more reliable.

Keywords: expansive soil slope; wetting–drying cycles; crack propagation; discrete element method(DEM)

Figure 3. (a) Measuring points layout of the discrete element slope model; (b) discrete element slope model.

Figure 4. Division of crack area of expansive soil slopes.

Figure 5. Displacement diagrams of expansive soil slopes without wetting–drying cycle: (a) at 25,000 time steps, (b) at 50,000 time steps, (c) at 75,000 time steps, (d) at 100,000 time steps.

Figure 8. Displacement diagrams of expansive soil slopes after three cycles of wetting–drying: (a) at 25,000 time steps, (b) at 50,000 time steps, (c) at 75,000 time steps, (d) at 100,000 time steps.

Figure 10. Displacement diagrams of expansive soil slopes after five cycles of wetting–drying: (a) at 25,000 time steps, (b) at 50,000 time steps, (c) at 75,000 time steps, (d) at 100,000 time steps.

Figure 11. Relationship between displacement and reduction coefficient of slope measuring points after different times of wetting–drying cycles: (a) without wetting–drying cycle, (b) the first cycle of wetting–drying, (c) the second cycle of wetting–drying, (d) the third cycle of wetting–drying, (e) the fourth cycle of wetting–drying, (f) the fifth cycle of wetting–drying.

Wang H, Wang Y, Jin F. Stability of Expansive Soil Slopes under Wetting–Drying Cycles Based on the Discrete Element Method[J]. Water, 2024, 16(6): 861.

点击下方阅读原文查看论文链接