存在高渗透区的黏土心墙土石坝渗流稳定性分析  

Seepage stability analysis of earth and rockfill dam with clay core by considering high permeability zones

作　　者：彭铭[1] 毕竞超 朱艳 方坑龙[3] 李冰心 徐佳成 PENG Ming;BI Jingchao;ZHU Yan;FANG Kenglong;LI Bingxin;XU Jiacheng(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;China Shipbuilding NDRI Engineering Co.Ltd,Shanghai 200063,China;Capital Construction Department,Wenzhou Medical University,Wenzhou 325035,China;Zoina Land Limited Company,Shanghai 200050,China;China International Engineering Consulting Corporation,Beijing 100048,China)

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]中船第九设计研究院工程有限公司,上海200063 [3]温州医科大学基建处,浙江温州325035 [4]中南置地有限公司,上海200050 [5]中国国际工程咨询公司,北京100048

出　　处：《水利学报》2020年第11期1347-1359,共13页Journal of Hydraulic Engineering

基　　金：国家自然科学基金项目(41877234,41731283);国家重点基础研究发展计划项目(973计划)(2013CB036404);同济大学土木工程高峰学科-交叉学科项目;同济大学中央高校基本科研业务费专项资金项目;2019年湖南省水利科技项目。

摘　　要：黏土心墙土石坝是重要的挡水建筑物,心墙的低渗透性可以大幅降低坝体水力梯度,减少坝体发生渗透破坏的风险。然而心墙的质量问题(如局部高渗透区)会影响坝体的渗透稳定性,甚至酿成管涌溃坝等严重后果。以瀑布沟心墙土石坝为原型开展坝体渗流大型水槽模型试验,并结合有限元数值模拟方法研究高渗透区对坝体内部渗流场和渗流稳定性的影响。试验表明高渗透区域将改变心墙的渗流场,成为优势渗流通道,导致高渗透区域附近孔压值大幅上升,同时高渗透区域的存在将显著提升坝体渗漏速率。试验与模拟结果一致表明,随着高渗透区域逐步上移,高渗透区所在位置处的孔隙水压力增大,坝体渗漏量减小。高渗透区和心墙的渗透系数增加都会使心墙孔压值和渗漏量增加;随着高渗透区的渗透系数的增大,心墙坝渗流稳定性系数降低,导致坝体稳定性下降;随着心墙渗透系数的增大,高渗透区水力梯度略微减小,但心墙整体临界水力梯度下降,坝体稳定性降低。所得结论可为基于监测数据反演分析心墙的质量问题和评估坝体的安全性能提供依据。Rockfill dams with clay core are important water-retaining structures.The low permeability of the core wall can highly reduce the hydraulic gradient of the rest dam body and the risks of seepage fail⁃ure to the dam body.However,the quality of the core wall(such as local high-permeability zones,)will affect the seepage stability of the dam body,which may lead to serious consequences such as piping fail⁃ure.In this paper,large-scale water flume tests of seepage stability is performed with the prototype of the Pubugou soil and rockfill dam.A numerical model of finite element which was validated with the test re⁃sults was used to study the influence of the high-permeability zone(HPZ)on the seepage field and stabili⁃ty of the model dam.The test shows that the HPZ will change the seepage field of the clay core and be⁃come a dominant seepage channel,and meanwhile,the existence of high permeability area will significant⁃ly increase the seepage rate of the dam body.The test and simulation results both show that the pore wa⁃ter pressure of the upper part of the clay core increased with the rising of the HPZ position;while the leakage volume of the dam decreased at the same time because of lower water pressure of the HPZ.With the increase of the permeability of the clay core and the HPZ,the pore water pressure of clay core and the leakage rate both increased.The seepage stability of the dam would be reduced with the increase of the permeability of the HPZ and the water level.Although the increase of the permeability of the clay core will leading to decrease of the hydraulic gradient in the HPZ,the increase of the hydraulic gradient in the clay core would lead to decrease of the seepage stability of the clay core.The results obtained in the pa⁃per offer basis on the back analysis of the clay wall quality and the assessment of the safety and perfor⁃mance of the dams.

关 键 词：土石坝 高渗透区 孔隙水压力 黏土心墙 渗流稳定性 

分 类 号：TV641.4[水利工程—水利水电工程]