水布垭枢纽地质研究与实践  

Geological research for Shuibuya hydropower station and practice

作　　者：徐瑞春[1] 段建肖 

机构地区：[1]长江水利委员会设计院,湖北武汉430010 [2]长江水利委员会三峡勘测研究院,湖北宜昌443002

出　　处：《人民长江》2007年第7期1-6,共6页Yangtze River

摘　　要：水布垭水电站工程有两个第一:一个世界第一,是目前世界最高面板堆石坝(坝高233 m);一个国内第一,是国内在强岩溶化地区建设的抬高水头最高(203 m)的大坝。水布垭坝址岩层缓倾上游,建坝岩体软硬相间,分布有多层剪切带和缓倾角断层,还有煤系地层平卧于河床坝基下,这样的坝基岩体决定了不能兴建混凝土高坝。坝址区天然建筑材料丰富,当地材料坝对岩体要求较低,其中混凝土面板堆石坝不仅对岩体条件要求较低,且具有稳定性好,适应性强,建设速度快,总体安全程度较高等综合优点,作为选定坝型。勘察期间针对坝址地质条件进行了广泛的研究与论证,坝址存在3大主要地质问题:①环境地质问题,坝前库首地段分布有18个总量近1亿m3的滑坡与危岩体,坝下游泄洪雾雨区还分布有14个规模不等的滑坡、变形体和土体斜坡等,还有一个相对比高达360 m、具不利地质结构(上硬下软)的马崖高边坡;②坝址防渗问题,峡谷两岸岩溶强烈发育,勘察期和施工期实际揭示的岩溶洞穴之多就像筛子一样,清江枯水位197 m高程,大坝正常蓄水位400 m高程,坝前抬高水头203 m,解决岩溶绕坝渗漏问题是枢纽工程能否成立的关键技术问题之一;③软岩成洞问题,这里地下洞室较多、岩体条件很差,特别是在地下厂房的中下部,软岩相对集中,垂直开挖形成地下厂房,成洞问题难度很大,在工程建设中,采取了一系列有效措施,以适应这一复杂的地质条件并取得了成功。There are 2 tops in Shuibuya hydroproject: the highest faced rockfill dam(dam height 233m) on the world,the dam with the largest water head(203 m) constructed in strong karst area in China.During reconnaissance,the wide research and demonstration for geological condition in the dam site area had been carried out,3 main geological problems in dam site area existed.① Environmental geological problem.18 landslides and dangerous rock mass with total volume of 100 million m3 distribute in front area of the dam,and 14 landslides,deformation bodies and soil slopes with different scales distribute in downstream foggy rain area of flood discharge,in addition,the Maya high sideslope with relative height of 360m and unfavorable geological structure(hard in the upper part and soft in the lower part) is located at the downstream area.② Dam site seepage prevention issue.The karst developed strongly in both banks of the gorge,the karst caves revealed in reconnaissance and construction periods like screen,the dry water level of the Qingjiang river is El.197 m,the normal water level of the reservoir is El.400 m and the water head in front of the dam is 203 m,the successful controlling dam by-pass seepage is one of the key technical issues for the dam construction.③ Tunnel shaping in soft rock.the underground caverns of the project is multiple and the rock mass condition is unfavourable,especially in middle and lower parts,the soft rock concentrates comparably,cavern shaping for underground power house by vertical excavation is difficult.In the construction,a series of effective measures were adopted to treat the complicated geological condition and the construction was successful.

关 键 词：弱岩溶地块 基本地质条件 变岩溶化岩体为裂隙性岩体 岩溶发育史 水布垭水利枢纽 

分 类 号：P642.254[天文地球—工程地质学]