多元结构地基对防渗墙渗透溶蚀演化规律的影响  

Influence of Multi-Structure Foundation on Evolution Law of Leakage Dissolution of Cutoff Wall

作　　者：甘磊[1,2] 刘源 沈振中 徐力群[1] Gan Lei;Liu Yuan;Shen Zhenzhong;Xu Liqun(College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing 210098,P.R China;State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Hohai University,Nanjing 210098,P.R China)

机构地区：[1]河海大学水利水电学院,南京210098 [2]河海大学水文水资源与水利工程科学国家重点实验室,南京210098

出　　处：《地下空间与工程学报》2024年第1期287-301,310,共16页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(52379123);江苏省自然科学基金(BK20201312);河海大学优秀研究生学位论文培育项目(422003465)。

摘　　要：深厚覆盖层地基渗透性能和厚度变化会影响坝基渗流场的分布,进而改变坝基防渗墙溶蚀演化进程。为研究多元结构地基变化对防渗墙渗透溶蚀的影响机制,结合流体力学、化学动力学理论和对流-扩散方程,提出覆盖层地基混凝土防渗墙渗透溶蚀耦合分析模型,研究强透水层、弱透水层和第三透水层厚度及渗透系数对防渗墙中钙离子浓度、孔隙率和渗流特性的影响。结果表明:随服役年份增长,防渗墙钙离子浓度表现为先快速增长至峰值,随后不断下降的趋势,孔隙率和渗透系数呈指数型增长变化规律,大坝总渗透流量不断增大;各影响因素中,弱透水层渗透系数对防渗墙钙离子浓度、孔隙率和大坝总渗流量的影响最大,其次为强透水层厚度及其渗透系数;各工况下混凝土防渗墙使用年限为38.46~44.00年。研究成果可为深厚覆盖层多元结构地基上的土石坝工程的长效服役性能评估提供理论依据。The change of permeability and thickness of deep overburden foundation would affect the seepage field of dam foundation,and then change the erosion evolution process of cutoff wall in dam foundation.In order to study the influence mechanism of multi-structure foundation change on leakage dissolution of cutoff wall,a coupling analysis model of seepage and corrosion of concrete cutoff wall in overburden foundation was proposed by combining fluid mechanics theory,chemical dynamics theory and convection-diffusion equation.The effects of thickness and permeability coefficient of strong permeable layer,weak permeable layer and third permeable layer on calcium ion concentration,porosity and seepage characteristics of cutoff wall were presented.The results show that,with the increase of service years,the calcium ion concentration of the cutoff wall increases rapidly to the peak at first,and then decreases continuously.The porosity and permeability coefficient increase exponentially,and the total seepage flow of the dam increases continuously.Among the influencing factors,the permeability coefficient of weak permeable layer has the greatest influence on the calcium ion concentration,porosity and total seepage flow of the cutoff wall,followed by the thickness and permeability coefficient of strong permeable layer.The service life of concrete cutoff wall under various conditions is from 38.46 a to 44.00 a.The research results can provide theoretical basis for the long-term service performance evaluation of earth-rock dams on multi-structure foundation with deep overburden.

关 键 词：多元结构地基 混凝土防渗墙 渗透溶蚀 孔隙率 渗流特性 

分 类 号：TU452[建筑科学—岩土工程]