A seismic-induced landslide is a common geological catastrophe that occurs in nature.The Wangjiayan landslide,which was triggered by the Wenchuan earthquake,is a typical case in point.The Wanjiayan landslide caused ma...A seismic-induced landslide is a common geological catastrophe that occurs in nature.The Wangjiayan landslide,which was triggered by the Wenchuan earthquake,is a typical case in point.The Wanjiayan landslide caused many casualties and resulted in enormous property loss.This study constructs a simple surficial failure model based on the upper bound approach of three-dimensional(3D)limit analysis to evaluate the slope stability of the Wangjiayan case,while a traditional two-dimensional(2D)analysis is also conducted as a reference for comparison with the results of the 3D analysis.A quasi-static calculation is used to study the effect of the earthquake in terms of horizontal ground acceleration,while a parametric study is conducted to evaluate the critical cohesion of slopes.Rather than employing a 3D analysis,using the 2D analysis yields an underestimation regarding the safety factor.In the Wangjiayan landslide,the difference in the factors of safety between the 3D and 2D analyses can reach 20%.The sliding surface morphology as determined by the 3D method is similar to actual morphology,and the parameters of both are also compared to analyze the reliability of the proposed 3D method.展开更多
[目的]水土保持是保护和改善生态环境的重要途径,是生态系统可持续发展的重要基础,而区域尺度水土保持成效研究可为水土保护工作提供有效的理论依据。[方法]基于遥感技术,采用修正的通用土壤流失方程(revised universal soil loss equat...[目的]水土保持是保护和改善生态环境的重要途径,是生态系统可持续发展的重要基础,而区域尺度水土保持成效研究可为水土保护工作提供有效的理论依据。[方法]基于遥感技术,采用修正的通用土壤流失方程(revised universal soil loss equation,RUSLE)构建区域尺度水土保持率遥感估算方法体系,并估算山西省土壤侵蚀空间格局。[结果]山西省水土流失等级以中度侵蚀为主,水土流失面积约49545.68 km^(2),2022年水土保持率为68.38%,水土保持率高的等级面积占比最大。自然植被水土保持率高于农田,其中,森林水土保持率最高,为84.37%,且在自然植被与农田类型中,水土保持率高的等级面积占比最大,分别为48.11%,46.46%。水土保持率受坡度影响较大,且随坡度的变化呈现先显著减少后平缓波动的趋势。通过与已有研究成果对比,估算得到的山西省水土流失空间格局及规律与现有水土流失数据基本一致,且水土保持率估算结果与公布的水土保持率目标值呈显著强相关。[结论]综上所述,区域尺度水土保持率遥感估算方法可为水土保持生态工程及其他国家重大生态工程的成效和效益评估提供重要的理论和方法依据。展开更多
基金National Natural Science Foundation of China under Grant Nos.52378335 and 52322808.
文摘A seismic-induced landslide is a common geological catastrophe that occurs in nature.The Wangjiayan landslide,which was triggered by the Wenchuan earthquake,is a typical case in point.The Wanjiayan landslide caused many casualties and resulted in enormous property loss.This study constructs a simple surficial failure model based on the upper bound approach of three-dimensional(3D)limit analysis to evaluate the slope stability of the Wangjiayan case,while a traditional two-dimensional(2D)analysis is also conducted as a reference for comparison with the results of the 3D analysis.A quasi-static calculation is used to study the effect of the earthquake in terms of horizontal ground acceleration,while a parametric study is conducted to evaluate the critical cohesion of slopes.Rather than employing a 3D analysis,using the 2D analysis yields an underestimation regarding the safety factor.In the Wangjiayan landslide,the difference in the factors of safety between the 3D and 2D analyses can reach 20%.The sliding surface morphology as determined by the 3D method is similar to actual morphology,and the parameters of both are also compared to analyze the reliability of the proposed 3D method.
