三峡库区滑坡发生概率与降水条件的关系  

RELATIONSHIP BETWEEN LANDSLIDE PROBABILITY AND RAINFALL IN THREE GORGES RESERVOIR AREA

作　　者：陈剑[1] 杨志法[1] 李晓[1] 

机构地区：[1]中国科学院地质与地球物理研究所工程地质力学重点实验室,北京100029

出　　处：《岩石力学与工程学报》2005年第17期3052-3056,共5页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点基础研究发展规划(973)项目(2002CB412701;2002CB412702)

摘　　要：三峡库区位于长江上游,沿江两岸多为山地地形,滑坡灾害发生频繁,尤其是大、中型滑坡比较发育。这些滑坡灾害数量多、分布广、规模大,对当地的经济建设和生命财产造成了很大的危害,如何对滑坡进行有效的预测预报成为滑坡减灾防灾的关键。降雨是触发三峡库区滑坡的重要外动力因素之一。研究了三峡库区降雨型滑坡(体积≥104 m3)的发生时间与降水条件的关系,通过对该区112个滑坡–降雨事件进行数据统计和相关性分析,表明最大24 h雨强可作为降雨诱发滑坡的有效预报因子。基于易滑度分区的滑坡概率预报思路,根据三峡库区的地形地貌、地质构造和岩性组合等特点,初步将三峡库区分为A,B两个预报区,利用统计方法得出了各区在不同降水条件下滑坡的发生概率。结果表明,由于地质环境因素的不同,两区滑坡的发生概率具有明显差异,表明两区降雨诱发滑坡可能存在不同的机理。基于易滑度精细分区的降雨概率预报方法可望实现对突发性滑坡进行实时有效的预报。The Three Gorges Reservoir area is located at the upper reaches of the Yangtze River, where the geological hazards occur with high frequency, especially the major landslides are fully developed at the bank slopes along the river. These landslides are characterized by great amount, extensive distribution and big magnitude, often causing serious loss and casualty in local areas. How to predict landslides is the key to prevent hazards and reduce economical loss and casualties. The rainfall is the dominant exterior factor triggering the landslides. Based on statistic analysis of the data of 112 landslides（volume≥ 10^4 m^3）, the relationship between landslide and rainfall is derived. It is suggested that the temporal prediction criterion of landslides in the local area be established by the maximum 24-hour rainfall. In terms of the characteristics of landform, lithology, geological structures etc., the Three Gorges Reservoir area is divided into two parts for landslides prediction. Using the maximum 24-hour rainfall in 72 hours as the prediction index, the occurrence probabilities of landslides are determined in different rainfall conditions for the two subareas. The distinct difference of landslides probabilities between the two subareas indicates that their different mechanism of rainfall induced landslides. Based on the coupling analysis of the geology and meteorology, it is possible to improve the precision of the landslide forecast.

关 键 词：边坡工程 三峡库区 滑坡 发生概率 易滑度 降雨变量 预报判据 

分 类 号：P642.22[天文地球—工程地质学]