陕北黄土崩塌灾害风险评价指标体系构建

在滑坡的易发性、危险性和风险评价中,评价指标的选取和定量化是非常关键的。目前国内外采取的主要方法是利用GIS工具提取地形、岩性、距河流或断层带的距离、土地类型、植被、降雨、河流密度等因子进行分析和计算。这些指标在滑坡易发性和危险性区划中得到了广泛应用并取得了丰硕的成果,但也有一些局限性,具体表现在3个方面:一是不能针对不同的滑坡类型提供不同的评价指标体系;二是提取的这些因子中在区域上有些是共性因子,如岩性、降雨等;三是尚未建立一个完整的风险评价指标体系。本次研究专门针对陕西北部地区广泛发育的一种称之为"黄土崩塌"的滑坡类型,运用国际上流行的滑坡风险管理理论,确定其风险评价总体指标体系;基于大量野外调查数据的统计规律,分析了黄土崩塌危险性的主要来源和影响危害性的主要因素,从失稳可能性评价指标、崩塌强度评价指标、承灾体评价指标和易损性评价指标4个方面共确定了16大类36个评价指标。该指标体系的构建可为进一步的陕北黄土地区斜坡单元崩塌灾害风险评价提供基础。

The construction of factors for assessing the risk of collapse at loess slopes in northern Shaanxi Province

The selection and quantification of factors are very important in landslide susceptibility, hazards and risk assessments. At present, GIS tools are widely used in the world to extract the information of topography, lithology, distance from river or fault, land use, vegetation, precipitation, density of river, etc. These factors have been applied to assessing the landslide susceptibility or hazards with great achievements, but they still have some limitations. Firstly, they can not supply a set of relevant factors for a specific type of landslide. Secondly, some of the factors, such as precipitation and lithology, show generality at a region scale,. Thirdly, the integrated risk assessment factors have not been set up yet. This paper studied a specific type of landslide called "loess collapse" which is widely developed in northern Shannxi Province, utilized the international popular landslide risk management theory to build up a general framework of assessing factors. On the basis of data statistics from field investigation, the authors analyzed the sources of hazards and influencing factors of damages. Totally 36 factors in 16 catalogs were set up in four aspects, i.e., slope failure, collapse intensity, elements in risk, and vulnerability. The construction of these factors will provide a basis for further assessment of loess collapse risks.