典型红粘土与膨胀土的对比试验研究

COMPARATIVE LABORATORY STUDY ON TYPICAL RED CLAY AND EXPANSIVE SOIL

通过室内试验对广西贵港红粘土、湖北荆门弱膨胀土与中膨胀土的物理力学性质指标、原状样脱湿过程中的强度变化、击实样泡水前后强度变化以及脱湿吸湿性能等方面进行了对比试验研究。结果表明:3种土原状样脱湿过程中的强度指标在土体裂隙性与基质吸力双重因素的作用下表现出完全不同的变化规律;由于红粘土与膨胀土膨胀性能上的差异,不同含水量的击实样泡水后的干密度峰值与加州承载比(CBR)峰值所对应的原击实样含水量比最优含水量有不同程度的增大;土体因矿物成分的差异而表现出明显不同的脱湿、吸湿速率。广西贵港红粘土与荆门膨胀土虽然在一些物理力学指标上具有相似之处,但其力学特性与水敏性特征具有明显的差异,在实际工程中应给予充分重视。

A comparative laboratory study is presented on the physical and mechanical indexes, strength changes of intact samples during the process of dehydration, strength changes of compacted samples after saturating, as well as the dehydration and humidity absorption capability for the red clay in Guigang, Guangxi, and weak-expansive soil and mid-expansive soil in Jingmen, Hubei. The results show that the strength of the three kinds of soils possesses different rules during the process of dehydration due to the double effects of matrix suction and fissure. Because of the different swelling properties of red clay and expansive soil, the water contents of compacted samples corresponding to the maximum of dry density and CBR after saturation are higher in different extent than those corresponding to the optimum water content. The properties of dehydration and humidity absorption of tested soils are different due to the difference in mineral compositions. Even though there are some similarities between red clay and expansive soil on the physical and mechanical indexes, but the mechanical behaviors and water-sensitivity of these two special soils are obviously different. Hence, enough attention should be paid to these problems in the practical engineering projects.