岩溶地区高面板坝渗流特性与防渗安全评价  

Seepage behavior and its control performance assessment for a high concrete faced rockfill dam in karst areas

作　　者：袁晶晶 陈益峰[1,2] 胡冉[1,2] 杨志兵 王国辉 徐建华 YUAN Jingjing;CHEN Yifeng;HU Ran;YANG Zhibing;WANG Guohui;XU Jianhua(State Key Laboratory of Water Resources Engineering and Management,Wuhan University,Wuhan,Hubei 430072,China;Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering(Ministry of Education),Wuhan University,Wuhan,Hubei 430072,China;Power China Zhongnan Engineering Corporation Limited,Changsha,Hunan 410014,China;Hubei Energy Group Loushui Hydropower Corporation Limited,Enshi,Hubei 445801,China)

机构地区：[1]武汉大学水资源工程与调度全国重点实验室,湖北武汉430072 [2]武汉大学水工岩石力学教育部重点实验室,湖北武汉430072 [3]中国电建集团中南勘测设计研究院有限公司,湖南长沙410014 [4]湖北能源集团溇水水电有限公司,湖北恩施445801

出　　处：《岩石力学与工程学报》2024年第2期481-494,共14页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51925906);湖北省自然科学基金创新群体项目(2022CFA028)。

摘　　要：江坪河面板堆石坝是一座修建于岩溶峡谷地区的200 m级高坝工程,在其建设和蓄水运行过程中,出现面板开裂及坝基局部渗压异常现象,工程防渗安全亟待评估。采用检查孔压水试验、反演分析和互相关分析等方法,研究大坝及坝基在蓄水运行过程中的渗流特性,系统评价大坝面板和坝基帷幕的防渗性能,揭示帷幕后坝基局部异常高渗压的成因机制。结果表明:大坝面板经防渗处理后,渗透系数较设计值增大3.6倍,但防渗性能满足大坝长期安全运行要求;岩溶坝基防渗处理质量达到设计标准,坝基渗漏量控制在合理范围内;左右两岸坝基帷幕后局部异常高渗压现象分别由断层和地层接触带的溶蚀作用产生,库水位变化产生的压力波动通过溶蚀通道快速向下游传导,防渗帷幕虽有效限制库水向下游的渗漏,但不能完全抑制压力向下游的传导,从而在溶蚀通道附近形成局部渗压异常升高现象。研究成果对江坪河水电站枢纽工程竣工验收及安全鉴定具有重要指导意义。The Jiangpinghe concrete faced rockfill dam is a tall dam of 200 m height located in a karst valley.During construction and reservoir impoundment,cracking of concrete face slabs occurred and an abnormal pressure rise was observed in the dam foundation downstream of the grout curtains,leading to an urgent need to reevaluate the safety of the seepage control system.Inspection borehole packer tests,inverse modelling and cross-correlation analysis were used to investigate the seepage characteristics through the dam and its foundation.On this basis,the performance of the concrete face slabs and the grout curtains was systematically assessed,and the mechanisms causing the local pressure rise in the dam foundation were clarified.The results show that the face slabs,though having a permeability 3.6 times higher than the design value after cracking and seepage treatment,perform well for long-term safety operation.The quality of the seepage control treatment at the karst foundation satisfies the design requirements,which limits the amount of leakage at a sufficiently low level.The local pressure rise in the dam foundation can be attributed to the hydraulic connection through a fault(at the left bank)and depositional contact zones(at the right bank),both of which have enhanced permeability due to groundwater erosion and provide channels for quickly transmitting the reservoir pressure towards downstream across the grout curtains.Although the grout curtains effectively reduce the leakage through the dam foundation,they are not able to completely inhibit the pressure transmission,hence making the abnormal pressure rise occur around the eroded channels.The results are of great significance for completion acceptance and safety evaluation of the Jiangpinghe Hydropower Project.

关 键 词：水利工程 岩溶坝基 渗流特性 防渗安全 面板堆石坝 反演分析 

分 类 号：TV61[水利工程—水利水电工程]