摘要
乳源县东坪镇地处粤北山区,地形起伏大,地质灾害隐患突出,严重影响当地群众的生产生活,防灾减灾形势严峻。本文以乳源县东坪镇为研究区,根据受威胁居民区的分布情况,将靠山有威胁对象的斜坡单元列为调查区,应用综合指数法开展山边行政村地质灾害风险评价。通过选取坡度、坡形、地形起伏度、岩土体类型、地质构造、植被覆盖和土地利用类型7个关键因子构建评价体系,结合各因子权重计算某一斜坡单元的地质灾害易发性;在此基础上,叠加某一降雨工况下斜坡失稳的概率,从而评价该斜坡单元的地质灾害危险性;再结合承灾体易损性评价因子与权重值求积后叠加,可计算得到某一斜坡单元的地质灾害易损性;最后通过风险矩阵计算获得该斜坡的风险等级。研究结果表明:(1)东坪镇山边行政村地质灾害易发性与人类活动关联显著,高易发区主要分布于龙溪村、汤盆村等交通干线沿线,与历史灾害隐患点的空间分布高度吻合;(2)地质灾害危险性受降雨强度影响显著,不同降雨工况下,地质灾害危险性呈非线性变化;(3)高易损区位于G323国道与X358县道沿线(方武村、汤盆村等),该区域人口与基础设施密集导致脆弱性较高;(4)在“24小时累计降雨量100 mm”条件下,研究区地质灾害风险等级整体较低,高风险区仅1个斜坡单元,中风险区58个斜坡单元,低风险区410个斜坡单元;在“24小时累计降雨量250 mm”条件下,研究区地质灾害风险等级显著升高,高风险区激增至126个单元,中风险区144个斜坡单元,低风险区降至199个斜坡单元。本文研究为东坪镇山边行政村地质灾害风险管理提供了精细化、定量化的科学依据,突出强调了极端降雨情景下风险分布的动态变化特征,对地方政府制定差异化的防灾策略具有重要参考价值。
Dongping Town in Ruyuan County is situated in the mountainous region of northern Guangdong Province,an area marked by pronounced topographic variations and significant geological disaster risks.These hazards have a severe impact on local production and livelihoods,making disaster prevention and mitigation an urgent priority.This study focuses on Dongping Town as the research area.Based on the distribution of threatened residential zones,slope units adjacent to mountains that pose potential risks were delineated as the survey area.The comprehensive index method was applied to assess geological disaster risk in the mountainous administrative villages.An evaluation system was constructed using seven key factors:slope gradient,slope shape,topographic relief,lithology and soil type,geological structure,vegetation coverage,and land use type.By combining the weights assigned to these factors,the geological disaster susceptibility for each slope unit was calculated.On this basis,the probability of slope instability under specific rainfall scenarios was incorporated to evaluate the hazard level of geological disasters for the slope unit.Furthermore,by overlaying the product of vulnerability assessment factors and their corresponding weights for exposed elements,the vulnerability to geological disasters for each slope unit was computed.Finally,the risk level was determined using a risk matrix.The findings are as follows:(1)The susceptibility to geological disasters in the mountainous administrative villages of Dongping Town is closely associated with human activities.High-susceptibility areas are primarily distributed along major transportation routes such as Longxi Village and Tangpen Village,aligning closely with the spatial distribution of historical disaster risk sites.(2)The hazard level of geological disasters is significantly influenced by rainfall intensity,showing nonlinear variation under different rainfall conditions.(3)High-vulnerability areas are located along National Highway G323 and County Road X358(e.g.,Fangwu Village,Tangpen Village),where dense populations and infrastructure contribute to elevated vulnerability.(4)Under the scenario of"100 mm cumulative rainfall over 24 hours",the overall geological disaster risk in the study area is relatively low,with only one slope unit classified as high-risk,58 as medium-risk,and 410 as low-risk.In contrast,under the scenario of"250 mm cumulative rainfall over 24 hours",the risk level increases markedly:high-risk units rise sharply to 126,medium-risk units number 144,and low-risk units decrease to 199.This study provides a refined and quantitative scientific basis for geological disaster risk management in the mountainous administrative villages of Dongping Town.It highlights the dynamic variation in risk distribution under extreme rainfall scenarios,offering valuable insights for local governments in formulating differentiated disaster prevention strategies.
作者
杨放丹
YANG Fang-Dan(Guangdong Institute of Mineral Resources Exploration(Guangdong Institute of Nuclear Geology Exploration),Guangzhou 510080,Guangdong,China)
出处
《华南地质》
2025年第4期883-894,共12页
South China Geology
基金
中央-自然灾害防治体系建设补助资金项目(H202402021)。
关键词
地质灾害
综合指数法
易发性评价
易损性评价
危险性评价
风险评价
广东省乳源县
geological disasters
comprehensive index method
susceptibility assessment
vulnerability assessment
hazard assessment
risk assessment
Ruyuan County Guangdong Province
