广东省暴雨型浅层滑坡灾害动力预警模型与气象风险预警研究

Research on risk early warning for rainfall-induced shallow landslides in Guangdong Province based on a dynamic slope instability model

针对县级地质灾害气象风险预警面临的精度及模型建设问题,根据广东省地质灾害主要发生在坡面残坡积浅表层的突出特点,通过对典型地质灾害进行物理模拟试验和数值模拟,研究广东省浅表层斜坡失稳发生机理。研究表明:边坡在暴雨条件下,斜坡岩土体容易在浅表层首先造成失稳,影响因素主要有降雨量、降雨历时、土体类别和坡体结构等因素。由此,对研究区划分斜坡单元,按各斜坡单元的坡长、坡度、岩土类型、分层及其关键物理力学参数开展斜坡单元概化分类,并将Green-Ampt降雨入渗模型和无限边坡稳定性评价方法相结合,优化构建了动力学斜坡稳定性评价模型。结合龙川县贝岭镇流域应用实例,初步探索了坡面单元尺度下地质灾害气象风险预警斜坡失稳动力学预警技术,可为广东省开展以斜坡单元预警为主要方式的县级地质灾害气象风险预警提供支撑。

In light of the accuracy and model construction challenges in county-level meteorological risk early warning for geohazards,and considering the prominent characteristics that these geo-hazards mainly occur on the shallow surface of residual slopes,the mechanism of shallow surface slope instability in Guangdong Province was studied through physical simulation experiments and numerical simulations of typical geo-hazards.The results show that the slope is easy to lose stability in the shallow surface layer under the condition of rainstorm,and the main factors are rainfall,rainfall duration,soil type and slope structure.Subsequently,by dividing the study area into slope units,we developed a generalized classification and numerical modeling of these units based on parameters such as slope length,slope gradient,rock and soil type,stratification,and key physical and mechanical parameters of each slope unit,and by combining the Green-Ampt rainfall infiltration model with the infinite slope stability evaluation method,the slope instability dynamics warning model was then constructed.Through the application in the basin of Beiling Town in Longchuan County,and the application of dynamic early-warning technology for slope instability in meteorological risk early warning for geological hazards was preliminarily explored at the scale of slope units,which can provide support for county-level geo-hazards meteorological risk early-warning based on slope unit early-warning in Guangdong Province.