三峡水库引水工程秦巴段工程地质条件研究

在系统调查研究三峡引水工程秦—巴段区域地壳稳定性、活动断裂、工程地质条件和重大工程地质问题的基础上,根据三峡引水工程秦巴地区的工程地质条件及其差异性,初步将其分为六个工程地质区段,即:Ⅰ—四川盆地沉积岩区、Ⅱ—大巴山南麓弧形断褶区、Ⅲ—大巴山断裂较密集的岩溶发育区、Ⅳ—南秦岭断裂较少发育的中轻变质岩区、Ⅴ—秦岭造山带断裂密集发育的高变质岩区、Ⅵ—渭河盆地第四系堆积区。总体评价:Ⅰ和Ⅵ段工程地质条件较好,Ⅲ和Ⅴ段条件较差,重大工程地质问题较多。其中,主要的工程地质问题是岩爆、大变形和突水,特别是秦岭主峰附近可能发生强岩爆、大巴山区可能引发大规模岩溶突水值得高度重视。从区域地质环境、地壳稳定性、线路工程地质条件和主要工程地质问题等因素综合分析3条比选线路的差异,初步认为秦巴段三条输水线路以中线相对较好。

The Engineering Geological conditions of the Qingling-Dabashan Sector of the Water Diversion Project from the Three Gorges Reservoir to the Yellow River

Based on investigations into regional crust stability, active faults, engineering geological conditions and important engineering geological problems of the Qingling-Dabashan sector of the water diversion project from the Three Gorges Reservoir to the Yellow River, the authors divided the region into six segments from the difference of engineering geological conditions, namely, I-the sedimentary rock segment in northeast Sichuan basin, II- the segment of arc faults and folds in the southern part of the Daba Mountain, III- the segment of faults and karsts in the Daba Mountain, IV-the mid-low metamorphic rock segment in the southern part of the Qingling Mountains, V-the segment of dense faults and high metamorphic rocks in the Qingling Mountains, VI-the segment of Quaternary sediments in Weihe basin. Of them, the I and VI segments have the best engineering geological conditions, while the III and V segments possess the worst conditions. There exist more important engineering geological problems in III and V segments than in other segments. Rock blasting, water bursting and intense deformation in tunneling of deep-long tunnels make up the important engineering geological problems. It should be noticed that strong rock burst can occur near the highest peak in the Qingling Mountains, and that intense water gushing may occur in the Daba Mountain area. According to a comparative analysis of regional geological setting, crust stability, line-engineering geological conditions and important engineering geological problems of the three lines at the Qingling-Dabashan sector, it is held that the midline project is better than the west-line and the east-line projects.