STUDY ON THE MASS TRANSFER PARAMETERS AND BARRIER PERFORMANCE FOR LINER OF CONTROLLED TYPE LANDFILL SITE

本研究采用渗透性系数(k)为1.0×10^<-6> ~ 1.0×10^<-10> m/s的细粒土进行离子渗流试验。在试验中，通过施加浓度梯度而不施加水力梯度来诱导密度流动和分子扩散，采用反问题方法研究影响细粒土运动的参数。对细粒土的屏障性能进行了数值分析。研究表明：(1)膨润土油混合物的渗透系数k和有效扩散系数D_d^*与有效孔隙度n_e有关；(2)从稠度极限可以相对容易地估算出膨润土-土-油混合物的有效孔隙度n_e和有效扩散系数D_d^*； (3) 5.0 m厚的土层（屏障层）的渗透系数k为1.0×10^<-7> m/s，与0.5 m厚的屏障墙的渗透系数k为1.0×10^<-8> m/s，其屏障性能存在较大差异。

In this study, ion seepage tests were conducted by using fine-grained soil with permeability coefficients (k) ranging from 1.0×10^<-6> to 1.0×10^<-10> m/s. In the tests, density flow and molecular diffusion were induced by giving the concentration gradient but not the hydraulic gradient to investigate the parameters affecting the movement of fine-grained soil in an inverse problem approach. Numerical analyses were also performed to evaluate the barrier performance of the fine-grained soil. The study revealed that (1) the permeability coefficient k of a bentoniteasoil mixture and the effective diffusion coefficient D_d^* are dependent on effective porosity n_e, (2) it may be possible to estimate the effective porosity n_e of a bentoniteasoil mixture and the effective diffusion coefficient D_d^* with relative ease from the consistency limit and (3) there is a considerable difference in barrier performance between a 5.0-meter-thick soil layer (barrier layer) with a permeability coefficient k of 1.0×10^<-7> m/s and a 0.5-meter-thick barrier wall with a permeability coefficient k of 1.0×10^<-8> m/s.