氯离子在黏土-膨润土屏障中迁移的离心试验研究

发布时间：2018-06-23 12:05

本文选题：黏土-膨润土屏障 + 离心模型试验　；参考：《岩土力学》2015年08期

【摘要】：将对流-扩散试验装置置于土工离心机中,以50g离心加速度运行12 h,研究了黏土-膨润土混合土样中Cl-的迁移扩散,使用解析解对试验结果进行拟合确定相关参数,分析了试验的相似条件,使用商用软件对离心试验原型进行模拟,与试验结果进行比较,探讨了离心机用于溶质迁移分析的比尺效应,最后通过数值分析研究了试验的黏土-膨润土屏障用于老垃圾填埋场防渗帷幕补强的效果。结果表明,土工离心机试验中,按实际出流量计算的实际孔隙水流速小于临界流速,两试样中的佩克莱数(Pe数)小于临界Pe数,机械弥散的作用可以忽略,试验满足扩散的相似定律;离心机试验所模拟的2.5 m厚衬垫原型,在水头5 m和10 m作用下3.42 a后均未被击穿;常重力下试验土样的渗透系数为8.5×10-8 cm/s,有效扩散系数为7.82×10-7 cm2/s,对试验原型进行的数值模拟表明,n倍重力加速度下,土工离心机可以1/n尺寸的试样实现对原型的模拟,同时将对流和扩散作用下的溶质迁移时间缩短至原型的21/n;试验的黏土-膨润土屏障用于老垃圾填埋场防渗补强,可显著减缓溶质迁移,防渗补强后可满足渗滤液迁移扩散的控制要求。
[Abstract]:The convection-diffusion test device was placed in a geogrid centrifuge and operated at 50 g acceleration for 12 h. The migration and diffusion of Cl- in clay and bentonite mixed soil samples were studied. The analytical solution was used to fit the test results to determine the relevant parameters. The similar conditions of the test are analyzed, and the prototype of centrifugal test is simulated by commercial software. The scale effect of centrifuge for solute transport analysis is discussed by comparing the results with the test results. Finally, the effect of the clay-bentonite barrier on the reinforcement of the impervious curtain in the old landfill is studied by numerical analysis. The results show that in the geotechnical centrifuge test, the actual pore water velocity calculated according to the actual discharge rate is less than the critical velocity, and the Pe number in the two samples is less than the critical Pe number. The effect of mechanical dispersion can be neglected. The experiment satisfied the similar law of diffusion, and the prototype of 2.5 m thick liner simulated by centrifuge test was not broken down after 3.42 years under the action of water head of 5 m and 10 m. The permeability coefficient and effective diffusion coefficient are 8.5 脳 10 ~ (-8) cm / s and 7.82 脳 10 ~ (-7) cm ~ (-2) / s respectively under constant gravity. The numerical simulation of the prototype shows that the geotechnical centrifuge can simulate the prototype at a scale of 1 / n. At the same time, the solute migration time under convection and diffusion was shortened to 21 / nof the prototype, and the clay bentonite barrier was used to reinforce the old landfill, which could significantly slow down the solute migration. The anti-seepage reinforcement can meet the control requirements of leachate migration and diffusion.
【作者单位】：上海大学土木工程系;浙江大学软弱土与环境土工教育部重点实验室;
【基金】：国家自然科学基金项目(No.51178260,No.51478256) 浙江大学软弱土与环境土工教育部重点实验室开放课题(No.2011P02) 上海市教委科研创新项目(No.14YZ005)
【分类号】：TU411

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