地质科技通报 (May 2024)
Deformation evolution law and early warning criterion of Xinhua landslide
Abstract
Objective To reveal the deformation evolution of the Xinhua landslide in Luding County, Sichuan Province under the comprehensive effects of reservoir impoundment, reservoir water level fluctuations and seasonal rainfall, and to explore the progressive cumulative effect of the strength degradation of the landslide rock and soil mass under the coupling of multiple factors. Methods In this paper, based on a field investigation and multisource long sequence monitoring data analysis of the Xinhua landslide in the reservoir area of the hydropower project, combined with the three-stage evolution characteristics of the landslide cumulative deformation-time (S-t) curve and the measured S-t curve of the Xinhua landslide, the evolution stages of the three-step deformation cycles of the Xinhua landslide are identified and divided. At the same time, the improved tangent angle method is used for calculation and analysis, and a quantitative classification standard for Xinhua landslide classification early warning based on the improved displacement tangent angle early warning threshold is constructed. Results The results show that the short-term large increase of water level during the initial impoundment period, the rapid decrease of water level during the reservoir operation period and the influence of seasonal heavy rainfall are the main factors to accelerate the deformation of the Xinhua landslide. Conclusion According to the analysis and discussion, the improved displacement tangent angle early warning threshold can provide guidance for identifying the current stability state and potential risks of the Xinhua landslide to a certain extent, but multiple early warning indicators should still be considered, and the signs of macroscopic deformation and failure of landslides should be integrated for judgement.
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