碱溶液对GMZ膨润土膨胀性和渗透性的影响

Performance alteration of compacted GMZ bentonite submitted to hyper-alkaline solution

利用适用于碱性溶液入渗的膨胀渗透仪,对不同初始干密度的高压实高庙子(GMZ)膨润土进行膨胀、渗透试验,试验中用NaOH溶液模拟碱性孔隙水。试验结果表明:在碱溶液入渗作用下,各试样的膨胀力均呈现双峰变化形态;相同初始干密度试样的膨胀力随入渗碱溶液浓度的增大而减小,渗透系数则随着溶液浓度的增大而增大;碱溶液浓度相同时,试样的膨胀力随初始干密度的增大而增大,渗透系数随干密度的增大而减小;碱性孔隙水的长期入渗会减小高压实GMZ膨润土的膨胀性、提高其渗透性,最终降低膨润土的缓冲性能。

Using swelling-permeameter suitable to hyper-alkaline infiltration, an experimental study was carded out on compacted Gaomiaozi （GMZ） bentonite with different initial dry densities, where the NaOH solution was used to simulate hyper-alkaline pore water. The results show that the swelling pressure curves show a two-peak shape; with the same initial dry density, the swelling pressure of samples decreases with the concentration of the solution, while the permeability increases; with the same concentration of NaOH solution, the swelling potential of samples increases with the dry densities, while the permeability decreases; therefore, the high expansion and low permeability of densely compacted GMZ bentonite will be reduced after having been submitted to long-term infiltration of hyper-alkaline pore water.