Abstract:

The creep landslides induced by reservoir impoundment are widely distributed. They are large in scale and highly hazardous. To address these problems, a dynamic risk evaluation model for creep landslide instability, applicable to engineering practice, was established by introducing the RLE indicator. Based on extension theory, a comprehensive risk evaluation system was constructed by integrating internal physical and mechanical parameters such as cohesion, internal friction angle, settlement rate, and inclination change rate with external environmental factors including rainfall intensity, relative reservoir water level, and its variation. The weights of the evaluation indices were determined through a combined subjective and objective weighting method, and the RLE quantitative results were used to achieve dynamic identification and real-time early warning of slope instability risk. The Wangjiashan Landslide, upstream of the Baihetan Hydropower Station, was used as a case study, and multi-source field monitoring data were employed to verify the validity and applicability of the proposed model. The results indicate that the RLE value increases from 1.50 (Level Ⅱ) at the initial stage of impoundment to 2.92 (Level Ⅲ) on October 9, which is consistent with the deformation rate and the observed evolution trend of slope risk. The RLE is found to capture instability risk variations even when the SF shows insignificant changes. The RLE and SF dual-index joint model can provide multi-dimensional dynamic risk information support for creep landslides, better enabling scientific risk management of poor geological bodies at engineering sites.

Key words: risk level eigenvalue (RLE), stability factor (SF), creep landslide, risk assessment, monitoring and early warning