Risk Assessment Of Road Flood In Sichuan Province

The premise of carrying the work of disaster prevention and reduction is that assess the road flood scientifically and reasonably. A comprehensive and systemic evaluation model was built, based on comprehensions of road flood, to research the disaster-pregnant environment, hazards and risk assessment of road flood. The detailed research contents are:(1) The road flood is put into 7 types such as roadbed loophole, roadbed washout, roadbed subsidence, water damage on roadbed, accumulation-buried roadbed and bridge and culvert damage by torrential flood and debris flow, concrete pavement plate impending which based on the analysis of the data and failure patterns of road flood what happened in sichuan province in the past 11 years.(2)Sichuan province is divided into A’ba, Ganzi, Liangshan, nortwest sichuan mountain-hill around the basin, northeast sichuan mountain-hill around the basin and sichuan basin, according to the different characterics of road flood and natural conditions in sichuan province, to weight of each index differently and specially.(3)Primary indexes were selected according to complex factors which related road flood and these indexes were further screened based on the method of factor analysis and road flood’s disaster-causing factors, disaster-supporting body, disaster-pregnant environment and characteristics of damaged. And these indexes would be divided into most, high, medium and low hazard grades, based on the standards which have been built connection the forms of road floods with experts’ opinions, to constitute assessment indexes system and built the criterion of grade system. And then, Weight of each index was calculated by AHP.(4)According to the comprehensive of road flood and fuzzy probability theory and the membership functions to build a comprehensive and systemic evaluation model for hazard and disaster-pregnant environment assessment, and take a risk assess next.(5)Landform, geological condition, vegetation coverage, average annual rainfall, rainstorm, potential rood flood mileages are selected as the disaster-pregnant environment evaluation indexes. The result shows that sichuan area have divided into the most easy-happening area(7.78%), high easy-happening area(39.98%), medium easy-happening area(52.22%) and low easy-happening area(0.03%); To combine the results with road network density, the height from pavement to river and highway ratio to assess the hazard of road flood, the most hazard area, high hazard area and medium hazard area are respectively accounts for 3.22%, 67.51% and 29.28%, low hazard area is lost.(6)according to the results of hazard assessment, take GDP, road cost per kilomerer and population density into account to assess the risk of road flood. he risk rating of road floods in sichuan province are divided into most-risk, high-risk, medium-risk and low-risk area which account for 0.45%, 29.48%, 34.16% and 35.90% of total area respectively. The distribution of most-risk and high-risk area is primarily in sichuan brasin and some area of panxi economic zone. The distribution of medium-risk area is primarily in mountain-hill around the basin and the transition area between the sichuan basin and the tibetan plateau. The distribution of low-risk area is primarily in ganzi and a’ba area.These results are reasonable and consistent with road flood happened in recent years. The result show that the modle has rationality and reliablity and the results are scientific and useful, so this could offer reliable theoretical reference for preventing of the Liangshan area.