地质科技通报 (Mar 2024)
Geological hazard risk assessment of collapse and landslide under different rainfall conditions
Abstract
Objective This study provides a basis for the prevention, avoidance, management and control of geological hazards. The disadvantage of considering rainfall as a single inducing factor in the evaluation system of geological hazard risk should be overcome. In this paper, risk assessments of collapse and landslide geological hazards in the study area were carried out under four different rainfall conditions: heavy rain, rainstorms, heavy rainstorms and extraordinary rainstorms. Methods Yuanyang County, Yunnan Province, was selected as the study area, and the grid unit was chosen as the evaluation unit. Nine evaluation factors were selected, namely, landform type, elevation, slope, aspect, curvature, engineering geological rock group, land use type, distance from fault and distance from river, respectively. A weighted information model combining a subjective analytic hierarchy process and an objective information model was used to evaluate susceptibility to collapse and landslides in Yuanyang County. Results According to the natural discontinuity point method, Yuanyang County is divided into four types, low, medium, high and extremely high susceptibility areas, accounting for 21.55%, 35.46%, 25.53% and 17.16% of the area of Yuanyang County, respectively. According to the ROC curve, the accuracy of the zoning results was 0.812, and the zoning results were good. Based on the susceptibility assessment, taking the annual average maximum daily rainfall as the inducing factor, risk assessments of collapse and landslide geological hazards in the study area were carried out under four working conditions-heavy rain, rainstorm, heavy rainstorm and extraordinary rainstorm, and results for collapse and landslide geological hazards under four conditions: heavy rain ([25, 50) mm) and rainstorms([50, 100) mm), heavy rainstorm ([100, 250] mm) and extraordinary rainstorm (>250 mm) data were thus obtained. The results of geological hazard risk assessments under different rainfall conditions are compared and analysed, and the spatial rationality of geological hazard risk assessment results under different rainfall conditions is determined. Conclusion The collapse and landslide hazard evaluation results under different rainfall conditions are highly consistent with the actual survey results, confirming the high reliability and rationality of the evaluation results.
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