| With the great progress of national economy and the further accomplishment of the west development strategy, the developing of hydraulic and hydroelectric resources has come into an unprecedented phases in China. Up to now, statistically the number of water conservancy and hydroelectric project constructed or pre-constructed in the karst area has been over 90 in China.Wudu reservoir is the water source of the Wudu water supply project. The project is a large-sized water conservancy project, the major purpose of which is flood control, irrigation as well as generation of electric energy and water supply to the city and countryside. The designed type of the dam is rolled concrete dam, with the maximum length of 119.4m, the total length of 727m, the dam top elevation of 660.4m, the check flood level of 659.43m, the total storage capacity of 5.72×108m3 and installed capacity of 3x50MW. The statigraphic sequence of the dam foundation is Guanwushan group belonging to the mid series of Devonian system (D2gn). The stratigraphy of dam foundation is mainly comprised of limestone, dolomite with marlite. The inhomogeneity of the lithology and the difference of the rock dissolubility result in the complex hydrogeologic condition and the great influence upon the dam foundation rock mass quality.Based on the characteristics of Karst developing in the dam site, engineering geologic mapping, core drilling, adits exploring, geophysical investigation as well as a large amount of hydro geologic test and rock mechanic test have been finished during the course of the karst investigations.Based on the analysis and research of the data and information obtained from the various investigation methods as mentioned above, the following subjects have been discussed in the dissertation.①The engineering geologic condition about topography, stratigraphy, tectonic structure, the stability of regional tectonics and the phenomena of physical geology have been analyzed and researched, and then the engineering geologic condition of the dam site has been evaluated.②The characteristics of Karst in the dam site, which include the morphology and its distribution, the pattern of karst developing above or beneath the foundation of the dam, Karst groundwater regime etc. have been analyzed. After that, the mechanics about Karst formation as well as its characteristics has also been argued. On the basis of such analysis and research, the intensity zoning map of the Karst developing has been proposed and then the governing factor of the Karst developing has been analyzed, generalized or concluded.③On the basis of above analysis and research, by the method of geologic analysis, the influence of Karst developing on the rock mass quality of the dam foundation has been analyzed systematically and wholly, the classification of the rock mass quality in karst dam foundation has also been presented, the location of the dam foundation has been proposed, and then the treatments of deficiency on or beneath the dam foundation has been concerned in the dissertation. |
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