The Assessment Of Risk Of The Ground Fissures Based On AHP In Yuncheng Basin

The ground fissure's activities are frequent in Yuncheng Basin since ancient times, especially in the modern, with the rapid development of economic and human engineering activities, especially for high strength mining of underground water and the cone of groundwater depression continues to expand, resulting in land subsidence, causing a great deal of ground fissures. Wherever fissures arrive, causing houses cracked, ground facilities damaged, large areas of farmland irrigation leaked and destructed. Harmful levels of ground fissures required the appropriate risk assessment to quantify and grasp, which is related to the coordination of social affairs and the sustainable development. Therefore, we carry out the work of ground fissures disaster risk assessment is practical significance.This thesis apply the project's field survey results of "Shanxi Province's investigation of the ground subsidence and ground fissures" and "The evaluation and assessment of groundwater resources and environmental problems in Shanxi Province's six major basins, in the support of GIS technology, combination of the GIS spatial analysis and statistical methods, this article takes advantage of the foundation of ground fissures' land subsidence's spatial database and the development of the information management system of fenwei basins, and evaluating the risk of disasters of Yuncheng basin's fissures, and achieved the following results and progress:1.Based on the collected data in the study area, through the analysis of geographical, geological background and the distribution of Yuncheng basin fissures, and use the research results which have got,the paper summed up the formation mechanism and main influencing factors of cracks in Yuncheng basin.2.In the use of GIS spatial analysis techniques, this paper has achieved the layer processing of ground fissure risk assessment factors. Among them, at the time of using the method of buffer zone analysis to derive the required data information, having regard to the different scale fractures or fissures have different degree effects to the harmful levels of ground fissures' disasters, this article identified to create the appropriate width of the buffer zone according to their size, to avoid disadvantage as the regardless of the differences and buffering unified directly.3.On the basis of the thorough analysis of the ground fissures disasters of Yuncheng basin, using the AHP, the fissures hazard evaluation model of Yuncheng basin is established, and then put forward the risk index calculation model of the ground fissures. On this basis, using the corresponding weights which based on the each index factor and the complex analysis pattern of raster data to composite overlay automaticlly for multi-layer index factor and layer spatial information of Yuncheng basin, and receiving the ground fissure hazard zoning map. And then the study area was divided into four grades, such as high-risk, moderate risk, slight risk, and the area almost no risk, while the high-risk zone area is about 468.72 km2,7.6% of the total area; the moderate risk zone area is about 826.29 km2,13.5% of the total area; the slight danger zone area is about 2579.13 km2,42% of the total area; basic non-hazardous area is about 2265.39 km2,36.9% of the total area.