区域地质灾害评价预警的递进分析理论与方法

A method by to analyse four parameters for assessment and early warning on the regional geo-hazards

根据多年丰富的区域地质灾害考察和综合研究实践,作者架构了区域地质灾害评价预警研究的理论体系和工作方法,主要包括:(1)开展区域地质灾害综合调查;(2)建立地质灾害信息系统,包括基于GIS的区域地质灾害空间数据库和分层图形库(GGIS);(3)研究区域地质灾害分布与地形(高程、高差、坡度)、水系、植被、工程地质岩组、地质构造形迹、斜坡类型、降雨量分布和地震活动等的统计关系,为评价因子选取、分级和权重确定提供依据;(4)筛选提取评价预警研究因子体系,建立地质灾害发育因子、基础因子、诱发因子和易损因子体系;(5)创建研究区域地质灾害"发育度"、"潜势度"、"危险度"和"危害度"(简称"四度")的概念模型和数学模型;(6)在满足一定精度比例尺数字化图上划分计算单元,分别计算研究区域地质灾害"发育度"、"潜势度"、"危险度"和"危害度";(7)根据计算结果和应用目的,把相同或相近级别的图斑合并,分别编制区域地质灾害"四度"区划图;(8)根据"四度"区划结果提出研究区的地质灾害防治规划、分级监测预警目标区和地质环境可持续开发利用对策;(9)对重点地段或地点专门编制地质灾害防治预案和政府-社会联动的应急反应机制。上述9个步骤构成区域地质灾害评价预警的时空递进分析理论与方法,简称"四度"递进分析法(AM FP)。

On the basis of the rich knowledge from field experience and long-term researches, authors found a theoretical analysis method for assessment and early warning on the regional geo-hazard by four-stages. It consists of nine aspects: (1)geo-hazards field mapping, surveying objects including avalanche or toppling breakdown, landslides, debris-flows, ground collapse(particularly in karst area and underground mining area), ground fissures and unstable slope; (2)setting up information system (GGIS) of geo-hazards, such as spatial data base and digitized map layer banks based on GIS; (3)statistics interrelation study between geo-hazard distribution and all related factors, e.g. terrain (altitude difference), river system, vegetation, engineering geological lithological suite, structural features (folds anticline, syncline and faults), slope types, rainfall and seismic activity etc.; (4) screening out assessment factor system including geo-hazard distribution, geological environment, induced condition and vulnerable aspect such as human and wealth of society; (5) establishing concept system and its mathematic models for to analyze 'distribution parameter', 'potentiality parameter', 'dangerous parameter' and 'risk or harmfulness parameter' of the regional geo-hazards; (6) calculating regional geo-hazards' 'distribution parameter', 'potentiality parameter', 'dangerous parameter' and 'risk or harmfulness parameter' after dividing units on a digitized map by GIS; (7)drawing respectively 'distribution parameter', 'potentiality parameter', 'dangerous parameter' and 'risk or harmfulness parameter' distributive zoning maps by to merge same or similar level pattern based on the calculation results and a definite purpose; (8)putting forward mitigation strategy, arrangement for monitoring and early warning on geo-hazards and a series of countermeasure to develop the regional geo-environment; (9)working out a plan to control geo-hazards and meet an emergency for the government and the public society at the important section or site in an area. The above nine aspects form theory and method system to evaluate and forecast regional geo-hazards, which is called 'analysis method by four parameters' to go forward step by step for short AMFP. It is demonstrated that AMFP method is acceptable. An example is calculating 'four parameters' distribution of geo-hazards about 54175km^2 of the Three Gorges region of Changjiang River in China using calculation unit in 2.5km×2.5km. Another example is to have simulated 'dangerous parameter' distribution of Ya'an experimental field about 1067km^2 in Sichuan Province of China to using unit in 1.0km×1.0km by to utilize real time rainfall from twenty telemetry stations.