Quality Assessment Of Geological Environment In Xi'an

Urban geo-environment assessment is most important part of urban planning and urban geological disaster prevention and control planning. Xi'an is a historic city and is also the capital city of Shaanxi,which plays a vital role in the course of western development. It has an important practical significance that evaluating the quality of geological environment of Xi'an and depth-studying its geological problems, in promoting the western development and the healthy development of urbanization, and setting up a good geological environment.The thesis has analyzed main factors influencing city region geo-environment synthetically. On the basis of summarizing predecessors'experience and the characteristic of geo-environment problems of the Xi'an, it selected the terrain slope, ground fissures, land subsidence, loess collapsibility, fracture, the foundation bearing capacity and human engineering activities 7 indexes for evaluating the target. Combined with national standards, a geo-environmental quality assessment index system and grading standards of Xi'an are determined,. Based on the development platform of MAPGIS, the Spactial graphics database of Xi'an is established, and the thesis took query analysis, overlay analysis,digital elevation model analysis of spatial analysis function. River geomorphological zoning was as the evaluation unit, the precise value of quantitative indicators of the various districts is got by analysising. For the qualitative indicators, the expert scoring method is mainly used to quantify its indicators. For quantitative indicators, membership function values is used, according to the evaluation of grading criteria. The weights is calculated by using gray relational method, and finally the fuzzy comprehensive evaluation model is used to evaluate.The quality of geological environment in Xi'an was classified into best good,moderate, worst. And a review has been done according to their respective characteristics and the thesid put forward a reasonable preventive measures and protection recommendations. So,it further indicates that the system is reasonably practicable,with strong practicality.