The Assessment Of Risk Of Xi’an Ground Fissure Disasters About Line Project Based On GIS

Xian is a city of more than 3000 years history of civilization. Since 1959 several sporadic Ground Fissures were found in Xi’an, there have been 14 strips of the ground fissures proved. The ground fissures spread through buildings, roads and fields and destroyed them, which directly or indirectly caused enormous socio-economic losses. Ground fissures have become the most serious geological disasters of Xi’an and directly impede the traffic arteries of modern city that planning design and construction of Xi’an subway. How to assess and deal with ground fissure disasters have been a difficult and unavoidable problem of construction of Xi’an subway.Combined with survey data and results of the innovation project named “a comprehensive study of the geotechnical and geological environment in the construction of the great Xi’an” of science and technology in Shanxi Province, construct the assessment index system of risk of the ground fissures disaster along the Xi’an metro line No.2 based on analyzing development and characteristics of Xi’an ground fissure disasters. Using analytic hierarchy process and fuzzy analytic hierarchy process to assess the risk of ground fissures for subway and obtain corresponding results and figures with the appropriate grid area as the assessment unit based on ArcGIS10.1. Instance calculation and the assessment results show that the results of analytic hierarchy process to assess the ground fissure disaster in the area of study is better than that of the analytic hierarchy process.The main research achievements are as follows:(1) Analyze and comb geological environment and background of the development, distribution feature, activity regularity and cause of the ground fissures in Xi’an.(2) The establishment of index system and data processing. According to geological environment characteristics of the ground fissures disaster and results of genetic analysis, construct ground fissures disaster risk assessment index system for the study area and reorganize assessment data based on the ArcGIS10.1 software;(3) Establish the assessment model and assess the risk of the ground fissures disaster. Using analytic hierarchy process and fuzzy analytic hierarchy process to construct risk assessment model of ground fissure disaster for the area of study, assess risk of ground fissure disasters and acquire two ground fissure risk zoning maps of two kinds of assessment models. The assessment results of the fuzzy hierarchy analysis model are the more consistent with the fact than the other assessment model. The evaluation results of the fuzzy hierarchy analysis model divide the area of study into four different areas: The area of 1.3124km~2 is high-risk zone, 2.16% of the total area; The area of 16.8568km~2 is the moderate risk zone, 27.74% of the total area; the area of 31.6644km~2 is the slight risk zone, 52.11% of the total area; the area of 10.9300km~2 is the basic non-hazardous zone, 17.99% of the total area.