摘要
针对渗透溶蚀效应下特高土心墙堆石坝的渗流与溶蚀问题,构建了以孔隙水压力、固相钙浓度与钙离子浓度为自由度的水泥基材料渗流-溶蚀耦合模型。以长河坝工程为背景,研究了特高土心墙堆石坝的渗流溶蚀特征,探讨了渗透溶蚀效应下特高土心墙堆石坝的失效标准,预测了坝体的服役年限。渗透溶蚀效应降低了坝体的防渗能力,服役100 a后坝体浸润线逸出点将较初始时刻抬升1.95 m;随着服役年限的增加,覆盖层、副防渗墙的渗透坡降增加,心墙、主防渗墙和防渗帷幕的渗透坡降降低;水泥基材料固相钙溶蚀相对严重的区域集中在两道防渗墙中下部、固结灌浆靠下游侧及防渗帷幕,靠近复合土工膜和高塑性黏土的坝基防渗体溶蚀程度较低。从固相钙的分解率、渗透系数、渗流量、渗透坡降和边坡稳定等角度分析,认为考虑渗透溶蚀效应时长河坝的服役年限约为68.3 a,降低主防渗帷幕的初始渗透性可较为有效地延长坝体服役年限。特高土心墙堆石坝坝基水泥基结构渗透溶蚀效应不可忽视,其设计、运行及维护应充分考虑水泥基材料的渗透溶蚀效应。
In order to investigate the seepage and dissolution characteristics of super-high rockfill dams with soil core under the seepage-dissolution effect,a seepage-dissolution coupling model with three degrees of freedom that are pore water pressure,solid calcium concentration,and calcium ion concentration was proposed.The accuracy of the seepage-dissolution coupling model was verified via some existing experiments.Then,the model was employed to implement the seepage and dissolution analyses of the Changhe Dam project.The retirement index of the super-high rockfill dam with soil core was discussed to forecast the service life of the dam.It was demonstrated that the seepage-dissolution effect reduces the anti-seepage capacity of the dam.The spill point of the phreatic line is raised by 1.95 m.With the increase in service time,the anti-seepage curtain is gradually reduced by the auxiliary cutoff wall.Also,the hydraulic gradient of the overburden layer and auxiliary cutoff wall increases while the hydraulic gradient of the core wall,the main cutoff wall and the anti-seepage curtain decrease.It has a high and uniform degree that cement-based materials are middle and lower parts of two cutoff walls,anti-seepage curtain,and downstream side of consolidation grouting,while the dissolution degree of other cement-based materials near the composite geomembrane and highly plastic clay is relatively low.According to the decomposition rate of solid calcium,growth multiple of permeability coefficient,seepage discharge,hydraulic gradient,and slope stability,the service life of Changhe Dam is regarded as 68.3 years.Reducing the initial permeability of the main anti-seepage curtain can more effectively extend the service life of the dam.The results suggest that the seepage-dissolution effect of cement-based structures in dam foundation is essential for super-high rockfill dams with soil core,and the seepage-dissolution effect of cement-based materials should be considered in design,operation,and maintenance.
作者
徐力群
赵邵峰
沈振中
刘得潭
甘磊
张志银
XU Liqun;ZHAO Shaofeng;SHEN Zhenzhong;LIU Detan;GAN Lei;ZHANG Zhiyin(College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing 210098,China;State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Hohai University,Nanjing 210098,China;Datang Hydropower Science&Technology Research Institute Co.,Ltd.,Nanning 530007,China;Datang International Ganzi Hydroelectric Co.,Ltd,Kangding 626001,China)
出处
《水利学报》
EI
CSCD
北大核心
2023年第8期942-954,共13页
Journal of Hydraulic Engineering
基金
河海大学中央高校基本科研业务费项目自由探索专项(B200203039)
国家重点研发计划项目(2019YFC1510802)
国家自然科学基金面上项目(52179130)
国家自然科学基金雅砻江联合基金项目(U1765205)。
关键词
渗流-溶蚀耦合模型
水泥基材料
坝基防渗体
堆石坝
服役年限
长河坝
seepage-dissolution coupling model
cement-based materials
impervious structure of dam foundation
rockfill dams
service life
Changhe Dam
