考虑坝基防渗体渗透溶蚀效应的特高土心墙堆石坝服役年限可靠性分析  

Reliability analysis of service life for ultra-high core-wall rockfill dam considering the seepage-dissolution effect of dam foundation impervious structure

作　　者：赵邵峰 徐力群[1] 张宏伟[1,2] 沈振中 刘得潭[1,4] 甘磊 ZHAO Shaofeng;XU Liqun;ZHANG Hongwei;SHEN Zhenzhong;LIU Detan;GAN Lei(College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing 210098,China;College of Civil and Transportation 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)

机构地区：[1]河海大学水利水电学院,江苏南京210098 [2]河海大学土木与交通学院,江苏南京210098 [3]河海大学水文水资源与水利工程科学国家重点实验室,江苏南京210098 [4]大唐水电科学技术研究院有限公司,广西南宁530007

出　　处：《水利学报》2024年第11期1391-1403,1416,共14页Journal of Hydraulic Engineering

基　　金：国家重点研发计划项目(2019YFC1510802);国家自然科学基金面上项目(52179130);河海大学优秀研究生学位论文培育项目;中国国家留学生基金项目。

摘　　要：特高土心墙堆石坝坝基防渗体非均质特征显著,影响渗透溶蚀效应下长期服役性能的准确评估。本文基于KL展开法离散了水泥基材料参数随机场,构建了水泥基材料渗流-溶蚀耦合随机模型,利用神经网络,建立了随机场与服役年限的映射关系,发展了服役年限可靠性分析方法。以长河坝工程为背景,研究了坝基防渗体渗透系数、孔隙率和固相钙浓度为随机场情况下特高土心墙堆石坝的渗流与溶蚀特征,并对特高土心墙堆石坝服役年限进行了可靠性分析。渗透溶蚀效应会增大坝基防渗体渗透系数的空间变异性;坝基防渗体渗透系数、孔隙率和固相钙浓度为随机场情况下坝体与坝基总单宽渗流量是均质情况下的0.87~1.19倍;坝基防渗体95%保证率的服役年限为63.4 a;降低主防渗帷幕区与固结灌浆区渗透系数均值、减小固结灌浆区渗透系数空间变异性,是延长服役年限较为有效的方法。特高土心墙堆石坝设计、施工、运行与维护过程中应重视渗透溶蚀效应下坝基防渗体的空间变异性。Ultra-high core-wall rockfill dams exhibit highly non-homogeneous cement-based impermeability,which significantly affects the accurate assessment of the long-term performance of the dam foundation’s impervious structure under the seepage-dissolution effect.Based on the Karhunen-Loeve expansion method,the random field of cement-based material parameters is discretized.A multi-layer forward neural network model was established as the core to map the relationship between random fields and service life.A service life reliability analysis method was thereby developed.Taking the Changhe dam project as the background,the seepage and dissolution characteristics of cement-based materials under random permeability coefficient,porosity,and solid phase calcium concentration were studied.The accuracy of the neural network prediction model was verified,and service life reliability analysis of the ultra-high core-wall rockfill dams was carried out.Permeability erosion would enhance the spatial variability of the permeability coefficient of the cement base impermeability.The unit seepage discharge of the dam body and foundation under the random condition of cement-based material parameters is 0.87-1.19 times that under the average condition.The service life of the dam foundation with 95%guarantee rate is 63.4 years.From impermeability and mechanical perspectives,reducing the average permeability coefficient of the main anti-seepage curtain,average permeability coefficient and spatial variability of consolidation grouting can more effectively prolong the service life of the dam.The non-homogeneity of the cement-based impervious structure of the dam foundation should be emphasized in the design,construction,operation,and maintenance of ultra-high core-wall rockfill dams,considering the seepage-dissolution effect.

关 键 词：特高土心墙堆石坝 空间变异性 渗流-溶蚀耦合随机模型 可靠性分析 服役年限 神经网络 

分 类 号：TV223.4[水利工程—水工结构工程]