Mechanical Calculation of Landslide Stability Considering the Coupling Effect of Seepage and Stress and Optimization of Drainage Disaster Reduction

Abstract

This study presents a comprehensive investigation into the mechanical calculation approach for evaluating landslide stability, incorporating the coupled effects of seepage and stress, and proposes optimized drainage strategies to mitigate related disasters. As a frequently occurring and highly destructive geohazard, landslide stability is influenced by various factors, with the interaction between hydraulic seepage and the stress field playing a particularly pivotal role. Building upon Darcy’s law and the principle of mass conservation, the study derives governing differential equations for both steady and unsteady seepage conditions and establishes a corresponding seepage field model. A thorough examination is conducted on the coupling mechanism, illustrating how the seepage-induced volumetric force alters the internal stress distribution and, conversely, how stress variations influence the soil’s porosity and permeability coefficient. Based on this interaction, a finite element model that integrates both the seepage and stress fields is developed. Using a reservoir slope as a case study, numerical simulations reveal the temporal evolution of the seepage, stress, and displacement fields during rainfall infiltration. Findings indicate that under intense rainfall scenarios (rainfall intensity of 6.25 mm/h, totaling 187.5 mm over 45 hours), the pore water pressure in the near-surface soil rises sharply within 15 hours, approaching saturation, which leads to a more than 30% decline in effective stress and initiates significant soil deformation. Notably, the maximum vertical displacement reaches 12 cm, while the peak rate of horizontal displacement growth is 0.5 mm per hour, posing a substantial risk to slope stability. This paper concludes by recommending specific landslide mitigation measures, including the refinement of slope drainage systems and hydraulic design calculations. The effectiveness of these interventions is corroborated by field monitoring data, showing that, post-treatment, the average annual horizontal displacement is constrained to within 4.5 mm and vertical movement remains within −4.1 mm, representing a reduction of over 60% relative to the pre-treatment baseline. These outcomes offer a robust scientific foundation for landslide early warning, risk assessment, and control strategies.