九甸峡库区地质灾害分布规律及发展趋势

Distribution and Evolution Trend of Geological Disaster in Jiudian Gorge Reservoir

水库蓄水对库区地质灾害的发育有着重要影响,蓄水过程中库水位及侵蚀基准面的抬高等变化将会对库区地质灾害的发育起到了重要影响。为保障九甸峡水利枢纽的顺利建设和建成后的正常运营,以九甸峡库区为例研究库区地质灾害的分布规律及其水库蓄水后的发展趋势。基于对库区的详细的勘察资料的基础上,对库区地质灾害进行了系统地分析和评价。研究表明:蓄水后,库区沿岸产生多处库岸滑塌和小规模的新滑坡等灾害,塌岸宽度为50~100m,主要分布于洮砚以上的河段;库区浅层和深层滑坡共39处,蓄水初期库水位抬升诱发和加速了滑坡的变形破坏,蓄水后,大部分滑坡位于库水位之下或远高于库水位,受库水影响较小;蓄水对库区内滑坡的发育影响较大,对原有泥石流沟发育影响较小,泥石流沟的发育主要由降雨引起。

Reservoir impoundment has the important influence on the geological disasters. The reservoir began to impound in early 2008 because of the change of the water level and base level of erosion increase etc. , which plays an important role in the development of geological disasters in the process of water storage. To ensure the smooth operation of the Jiudian Gorge Water Conservancy construction and normal operation after the completion, we investigated the distribution of geological disasters and their development trend after impoundment in Jiudian Gorge Reservoir based on the survey of Jiudian Gorge Reservoir area as an example. Based on the detailed survey data of the reservoir area, the geological disasters were systematically analyzed and evaluated in the reservoir area, and the influence of the reservoir impoundment on the development of geological disasters was examined. The result showed that： （1） after reservoir impoundment, it produced many bank slumps and new small-scale landslide such as collapse along the banks of the reservoir area, and the width of bank collapse was 50-100 m, which mainly distributed in the upper reaches of Taoyan; （2） there were 39 shallow and deep landslides, which induced and promoted the deformation of landslides due to reservoir water level rising in the early impoundment phase, and the reservoir water level has a little effect on landslide stability due to the most of landslides locating below the water or far above the water level; （3） the reservoir impoundment has the impact on the development of landslides at a large degree, and has a little influence on original flow gully development, the flow gully is mainly induced by rainfall.