对膨润土掺砂混合土非饱和压实样,在不同温度和竖向应力为 50kPa 的条件下分别用纯水和渗滤液进行饱和膨胀试验以及饱和后的固结试验.利用变水头试验和固结试验,测量当渗滤液作为孔隙液体时不同掺砂率混合土的渗透系数. 试验结果表明:① 饱和液体种类对膨润土掺砂混合土膨胀变形的影响较大,用渗滤液饱和膨润土掺砂混合土的最终膨胀率比用纯水饱和的要小;② 当掺砂率较低时渗滤液饱和混合土的膨胀力比纯水饱和的小,当掺砂率为 50% 时 2 种液体饱和膨润土掺砂混合土的膨胀力几乎相等,混合土的膨胀变形和膨胀力随温度升高而减小;③ 在孔隙比相近的条件下纯水饱和混合土的渗透系数比渗滤液饱和的稍大,随温度升高渗透系数增大; ④ 在相同孔隙比条件下,固结试验方法测定的渗透系数小于变水头试验测定的数值.

A series of swelling tests were carried out on bentonite and sand mixtures saturated by pure water and landfill leachate; the mixtures sported different sand mixing rates. The tests were carried out under various temperatures and a vertical pressure of50 kPa. Furthermore, the swelling tests were followed by consolidation and falling head tests to measure hydraulic conductivity. The following test results were obtained. (1) The liquid used for saturating the unsaturated soils significantly influenced the swelling characteristics of the bentonite and sand mixture. The final swelling rate of the mixtures saturated by the leachate was less than that of the mixtures saturated by pure water. (2) When the sand mixing rate was low, the swelling pressure of the mixture saturated by the leachate was smaller than that of the mixture saturated by water. When the sand mixing rate was 50%, the swelling pressures of the mixtures saturated by leachate and water were nearly identical. Moreover, the swelling pressures and final swelling rates of the mixtures increased with decreasing temperature. (3) For similar void ratios, the hydraulic conductivity of the mixtures saturated using water was slightly higher than that of the mixtures saturated using leachate. Furthermore, the hydraulic conductivities increased with increasing temperature. (4) For similar void ratios, the hydraulic conductivity measured via consolidation tests was lower than that measured using the falling head test.