【作者】 李正顺；

【导师】 石豫川； 冯文凯；

【作者基本信息】 成都理工大学 ， 地质工程， 2008， 硕士

【摘要】 至到2006年,我国水力资源理论蕴藏量为6.19万亿千瓦时;而仅西部的水能蕴藏总量占全国的80%以上,其开发的潜力十分巨大。但该地区的河床普遍发育深厚覆盖层——厚度一般大于30m,评价其工程地质性质已成为西部水电开发过程中常遇到的难题之一。拟建丹巴水电站位于四川省甘孜藏族自治州丹巴县境内,是大渡河干流水电规划中的第8级电站,最大坝高116m,初拟装机容量156万kW。其坝址覆盖层工程地质条件比较复杂,最厚超过100m,且物质成份、结构及其成因复杂;各层物理力学性质和工程地质性质差异较大;特别在是坝基覆盖层中发育三层堰塞湖相沉积砂土层和数目众多厚度不一的砂土透镜体的情况下,坝基稳定问题尤显突出。在勘查资料、现场原位测试资料及室内试验等资料的基础上,分析了水卡子坝址深厚覆盖层中各层土的空间展布情况及工程特性,对坝址覆盖层地基承载力、地基沉降、渗透变形、砂土液化等进行了综合评价分析。分析结果表明抗滑稳定性满足工程需要;渗流模拟分析表明应该采用必要的渗流控制措施,控制覆盖层的渗流;沉降计算和数值模拟表明坝基的最大值沉降量满足规定要求;在Ⅶ度地震作用下,③、④、⑤层有发生砂土液化的可能。综合评价,选择④-2层为主要持力层,高程1940m为大坝建基面高程。对采用了渗流控制方案后的覆盖层渗流场进行模拟计算,结果表明灌浆帷幕能够有效地起到截渗的作用,控制覆盖层渗流效果明显。建议对埋深较浅的砂土体采用置换法处理,对于埋深较深的砂土体采用灌浆方法进行处理。更多还原

【Abstract】 By 2006, the theories reserves of water power resources are 6.19×10¹² kWH in China, and it is more than 80 percent of the country’s in the west of China. So this region has immense hydropower development potential. However, the riverbeds of this region’s rivers are the deep overburden whose thickness is general more than 30m. The engineering geology evaluation of those deep overburden has become a problem in the hydropower development process.The proposed Danba hydropower station located in Danba County of Ganzi Tibetan Autonomous Prefecture, Sichuan Province, is the eighth hydropower station in the Dadu river hydropower development plan. Its dam height is 116m, and its installed capacity is 1.56×10⁶kW. The engineering geology condition, composition, structure and origin of the overburden whose the most thichness is more than 100m are quite complex in the dam site. The physical properties, mechanical properties and engineering geological character of the overburden’s each parts are great different. It should be noted that there are three sand layers that are iacustrine sediments and large number of sand lens whose thichness is different. So the problem of dam stability is especially prominent.Based on those data of exploration, in-situ tests and laboratory tests, the spatial distribution and the engineering geological property of the overburden will be analyzed in the Shuikazi dam site. The allowable bearing capacity, the settlement of ground, the seepage field and the liquefaction of sand will be analyzed too.The analysis result indicated that the anti-slide stability of the dam meets the project needs. The seepage analysis result indicated that some seepage control measures should be used to decrease the leakage. The settlement calculation result and the finite element analysis result indicated that the maximum settlement value of the overburden meets the project needs. If aⅦearthquake takes place in the dam site, the sand of the③layer, the④layer and the⑤layer will take place liquefaction. Finally, the④-2 layer is considered as bearing stratum, and the elevation of the dam foundation is 1940m.A finite element model is built to simulate the seepage field of the overburden that is done curtain grouting, and the simulation result indicated that the curtain grouting can effectively decrease the leakage. The ground treatment option that are the dynamic consolidation replacement option that is use to treat the depth shallow sand and the grouting option that is use to treat the depth deep sand will be done.更多还原