某土石坝悬挂式混凝土防渗墙深度优选  

Research on Depth Optimization of Hanging Concrete Impervious Wall of an Earth-Rock Dam

作　　者：段玲玲 邓华锋[1] 支永艳 潘登 DUAN Lingling;DENG Huafeng;ZHI Yongyan;PAN Deng(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education,China Three Gorges University,Yichang 443000,China)

机构地区：[1]三峡大学三峡库区地质灾害教育部重点实验室

出　　处：《人民黄河》2019年第12期83-88,92,共7页Yellow River

基　　金：国家自然科学基金资助项目(51679127);国家自然科学基金重点项目(51439003)

摘　　要：在深厚覆盖层上修建土石坝,坝体和坝基的防渗效果直接关系大坝的安全。根据西南地区某土石坝坝址区工程地质条件,坝体采用沥青混凝土心墙防渗,深厚覆盖层采用悬挂式混凝土防渗墙方案,重点对悬挂式混凝土防渗墙深度进行了6种方案对比分析,确定防渗墙深度22 m时,大坝及坝基年渗流量和渗透比降满足要求。在此基础上,进行了多个工况的校核分析,计算结果表明,采用以沥青混凝土心墙和防渗墙为主的防渗体系,有效降低了坝体内部浸润线高度,浸润线在沥青混凝土心墙处骤降,下游坝坡内部孔隙水压力较小,最大坝高处浸润线降至排水层,下游出逸点位于下游排水体中下部,沥青混凝土心墙和混凝土防渗墙的渗透比降均小于允许值80,坝体填筑材料和天然砂砾石层的渗透比降均在允许渗透比降范围内,坝体、坝基渗流稳定,不会发生渗透破坏。When earth rock dams are built on deep overburden layers, the seepage prevention effect of dam body and dam foundation is di rectly related to the safety of dam. According to the geological conditions of an earth rock dam in the southwestern region of China, the dam body adopted the asphalt concrete core wall to prevent seepage, and the deep overburden layer adopted the suspended concrete anti seepage wall scheme, focusing on the depth of hanging concrete cutoff wall for 6 kinds of scheme comparison and analysis and determining that when the depth of the cutoff wall was 22 m, the annual seepage flow and seepage ratio drop of the dam and dam foundation met the requirements. On this basis, a number of working conditions were checked and analyzed. The calculation results show that the anti seepage system based on the asphalt concrete core wall and impervious wall effectively reduces the height of the internal seepage line of the dam, and the saturation line dips at the asphalt concrete core wall, and the internal pore water pressure of the downstream dam slope is relatively small, the maximum dam height where the saturation line falls to the drainage layer and the downstream exit point is located in the lower part of the downstream drainage body. The seepage ratio drop of asphalt concrete core wall and concrete cutoff wall is less than the allowable value of 80 and the seepage ratio drop of the dam filling material and the natural gravel layer is within the allowable percolation drop range. The seepage in the dam body and the dam foundation is stable and no seepage damage will be occurred.

关 键 词：深厚覆盖层 悬挂式防渗墙 渗流量 渗透比降 土石坝 

分 类 号：TV641[水利工程—水利水电工程] TV331