新疆伊犁果子沟地质灾害风险评价及其致灾因子

Evaluation on Geological Hazard Risk and Disaster-Causing Factors in the Guozigou Valley in Ili,Xinjiang

近年来,由气候变化引起的新疆山区地质灾害有增加的趋势。本文选取伊犁G30高速公路果子沟段为研究对象,采用国产ZY-3立体测图卫星数据制作山区高精度DEM和地形参数,运用GIS空间分析技术评估滑坡、崩塌、泥石流地质灾害风险,并采用频率比灾害风险指数进行致灾因子的敏感性分析。结果表明:(1)ZY-3的高精度DEM能够有效的计算崎岖的地形参数,获取的坡度、坡向、地表高程、沟谷密度等能够更好地进行灾害评估;(2)通过致灾因子分析得出,植被指数、坡度、坡向、地表高程、沟谷密度、地层岩性、断裂密度7个因子均与地质灾害相关,其中,植被指数最为敏感,在道路两侧影响尤为突出,这与道路建设、过度放牧等人类活动密切相关;(3)果子沟区域的地质灾害风险以道路边坡滑坡为主,分布在G30高速公路两侧,对道路造成的危害大,因此,G30高速公路两侧属于地质灾害高发区,需重点防治。

As the strategic pathway of the ancient Silk Road, the Guozigou Valley became as the energy transport corridor between Xinjiang and Central Asia, and also the thoroughfares of the material, social, economic and cultural exchange. In recent years, extreme weather, such as rainfall, temperature and snowmeh flood,increased dramatical- ly. Landslide, collapse, debris flows and other geological disasters occurred frequently and repeatedly in the area, so it is very important and urgent to assess the risk of geological disasters. The domestic scholars＇ researches on the geological disasters in the Guozigou Valley area were reviewed. However, it was hard to achieve the comprehensive assessment of geological disasters because of the lack of high accuracy terrain data and high spatial resolution of re- mote sensing images. In this paper,the domestically-produced high spatial resolution data of satellite ZY -3 were used to extract the terrain information in the Guozigou Valley area with the three linear array data of the ZY - 3, and the geological parameters along the G30 Highway in the area and the data of topography, vegetation, weather and hydrological conditions were applied to analyze the landslide risk based on the frequency ratio of disaster risk index model, so as to evaluate the regional geological hazard risk and analyze the key disaster-causing factors. Results are as follows： （1） The high accuracy DEM generation based on ZY -3 could be used to effectively calculate the rough terrain parameters including the slope, aspect, surface elevation, gully density, etc. and assess the disasters ; （2） The disaster-causing factors including the vegetation index, slope, aspect, surface elevation, gully density, formation li- thology and fracture density were closely related to the geological disasters. In comparison, the vegetation index was the most sensitive factor,and then the overgrazing and other human activities;（3） Landslide was the dominant geo- logical disaster in the study area. Therefore, the geological disasters occurred frequently along both sides of the G30 Highway in the Guozigou Valley area. The study could provide the auxiliary decision support to the risk evaluation and early warning of disasters.