重庆市涪陵区G319公路洪灾风险评估研究

RISK ASSESSMENT OF HIGHWAY FLOODING ON G319 ROAD IN FULING DISTRICT OF CHONGQING CITY

公路洪灾对公路安全畅通与发展建设具有重大威胁,并给公路行业带来巨大损失。以重庆市涪陵区境内国道319(G319)线为研究对象,依照该公路沿线地貌和水系分布情况,将其划分为340段作为风险评价尺度单元。从孕灾环境、致灾因子、承灾体因子和灾情因子等4个方面构建由15个评价指标组成的公路洪灾风险评估指标体系,并在ArcGIS软件平台支持下,通过相应的方法获取研究路线各路段洪灾风险评估各指标数据。采用综合评价方法建立公路洪灾风险评估模型,并据此计算得到涪陵区G319线各单元路段洪灾风险综合指数值,依据各风险等级阈值对路段洪灾风险进行综合分区。研究表明:涪陵区G319线洪灾风险以中风险为主,占路段总长度的65.17%;极高风险占0.76%;高风险占23.10%;低风险占10.96%,研究成果为公路防灾减灾及保障公路安全畅通提供科学依据。

China is a mountainous country,and mountainous area counts for 2/3 of the total land area. Complicated geological and topographical conditions, climates with severe storms, dense population and human activities have led to frequent mountain floods and thus caused huge seismic casualty and property losses. Highway construction is essential to the development of mountainous regions in China, and highways in hilly areas are especially significant as key lifeline engineering. Thus we need to ensure highway traffic safe and unblocked. However,as a kind of ribbon engineering,highways in hilly areas are faced with conspicu- ous floods prevention and control problems due to its long distance and complicated conditions in topogra- phy, geology, climate and hydrology. Highway flood disasters refer to disasters that are caused by rainfall or floods and will lead to a series of geological damage to road infrastructure. Highway flood is a great threat to fluent traffic and it has also caused huge losses to road industry. According to the statistics, direct economic losses of highway and its accessory structures in China caused by mountain floods were as high as 4 450 million Yuan. Among them,regions stricken by mountain floods at different levels between May and July, 2007,added up to 18 provinces （cities and districts）. Traffic in 8 express highways, 33 national roads and 578 provincial roads were interrupted and the economic losses reached 4110 million Yuan. National highway of G319 in Fuling District of Chongqing was researched in the paper,and it was divided into 340 zones according to the distribution of geomorphology and river system along the highway. With the support of ArcGIS,a risk assessment index system for highway flooding was established on the basis of floods de- veloping environment, floods causing factors, floods suffering factors and flooding factors. And the index data for flood risk assessment of each zone along G319 highway were acquired through various methods. The comprehensive index of each zone was calculated in the risk assessment model, and then risk zoning was completed according to the thresholds of different levels. The results showed that medium risk was the main risk of G319 highway in Fuling District,which accounted for 65.17~ of the total length. Besides, zones with extremely high risk,high risk and low risk accounted for 0.76% ,23.10% and 10.96% of G319 highway, respectively. Achievements in this paper will provide scientific references for the prevention and reduction of highway disasters, as well as safe and smooth transportation of highways.