降雨诱发斜坡失稳风险的气象预警

Meteorological warning for rainfall-induced slope instability risk

采用基准阈值和阈值调整方案构建斜坡尺度的降雨诱发斜坡失稳风险的气象预警模型,开展精细化滑坡风险管理.采用降雨强度-持续时间模型确定基准阈值;分析斜坡地质环境特征,从斜坡几何结构、岩土抗剪强度、水文地质条件、植被等方面选取调整因子,并确定基准斜坡;针对降雨入渗过程分析地质环境变化造成的斜坡稳定性变化,得出阈值调整方案.以浙江省平阳县为研究区,提出当地阈值计算公式,并根据各斜坡的地质环境形成各自不同等级的预警判据,综合预警有效率达到72%,效果良好.提出斜坡尺度的风险预警模型,实现了斜坡单元级别的精准预警,能够为“一区一阈值”精细化滑坡气象预警与风险管控提供新思路和参考.

A slope-scale meteorological warning model for rainfall-induced slope instability risk was constructed using benchmark threshold and a threshold adjustment scheme,in order to carry out refined landslide risk management.The benchmark threshold was proposed by the intensity-duration model.Adjusting factors were selected from slope geometry,rock and soil shear strength,hydrogeological conditions and vegetation based on the characteristics of the slope geological environment,and the benchmark slope was determined.The threshold adjustment scheme was obtained from the perspective of rainfall infiltration process,which explored the variation of the slope stability caused by the changes of the geological environment.Taking Pingyang County in Zhejiang Province as the study area,a quantitative formula was defined for calculating the threshold of individual slopes.Thresholds corresponding to different warning levels were formed based on the environment of each slope.The comprehensive early warning effectiveness rate reached 72%,which showed a satisfactory warning effect.An innovative slope-scale risk warning model was proposed.The precise landslide early warning at slope-unit scale was realized,which can provide new ideas and references for refined landslide early warning and risk management on purpose of“each-slope,each-threshold”.