高庙子膨润土和砂混合物膨胀变形特性及其预测

以高庙子钠基膨润土为试验材料, 利用单向固结仪进行一维浸水膨胀、浸水湿陷以及膨胀力试验, 分析了该膨润土在不同掺砂率下浸水膨胀和湿陷变形特性等问题, 并根据蒙脱石孔隙比的概念, 分析了饱和时的膨润土及其掺砂混和物的变形特性. 试验结果表明, 在低掺砂率下充分吸水膨胀湿陷或不变形时, 膨润土与砂混合物的蒙脱石孔隙比与垂直应力的关系在对数坐标系中是一条直线, 并且可据此预测膨润土及膨润土掺砂混和物在不同的干密度、掺砂率下吸水至饱和时的变形量及膨胀力. 分析砂骨架孔隙比对高掺砂率膨润土混合物的试验结果, 可预测形成砂骨架时的垂直应力值.

Swelling Deformation Characteristics of Gaomiaozi Bentonite-Sand Mixtures and Its Prediction

One-dimensional swelling deformation tests, collapse tests and swell pressure tests due to wetting were carried out on Gaomiaozi sodium bentonite by using oedometer, for analyzing the swelling and collapse deformation characteristics of mixtures of bentonite and quartz sand in different sand additions. Based on the concept of the montmorillonite void ratio, the deformation characteristics of bentonite-sand mixtures at saturation were consistently identified. Test results indicated that when the content of sand in the mixture was small, the relationship between the montmorillonite void ratio and vertical pressure at saturation was a straight line in the log scales. According to this line, the swelling deformation and pressure can be predicted when the bentonite or its mixtures at different dry densities or mixing ratios absorb water till saturation. Test results of the mixture with high sand fractions were analyzed by using the sand skeleton void ratio, which could predict whether the sand skeleton forms and the vertical pressure when the sand skeleton begins to form.