非饱和红土基质吸力与含水率及密度关系试验研究

非饱和土中存在的基质吸力对其性质有着十分重要的影响，而基质吸力又与土的含水率之间存在着密切的关系。为了探讨基质吸力与非饱和红土含水率和密度之间的关系，采用滤纸法在试验室进行了基质吸力的量测，得到了不同干密度下非饱和红土的土-水特征曲线，拟合出了该类非饱和红土土-水特征曲线公式。试验结果分析表明：在相同的干密度下，随着含水率的增加，基质吸力呈现出急剧减小的趋势。当含水率 <24 %时，这一变化规律特别明显。对参数 分析发现，在非饱和状态下基质吸力对红土强度的提高是有限的。通过分析不同干密度对基质吸力的影响规律得出，基质吸力在含水率较高时对密度状态的变化不敏感，而在含水率较低时对密度状态的变化比较敏感。

Experimental research of matric suction with water content and dry density of unsaturated laterite

The matric suction has very important influence on the characteristics of unsaturated soil; and it is closely relevant to water content. In order to discuss the relationship among the matric suction, water content and dry density, the matric suction is measured with filter paper method in laboratory. The soil-water characteristics curves (SWCC) for unsaturated laterite with different dry densities are obtained. The equations fitting the SWCC are presented for different dry densities of laterite. The test results show that the matric suction decreases with increasing water content under the same dry density; and the law is more obvious when water content is less than 24 %. The analysis of the parameter φ~b of unsaturated laterite shows that the strength of laterite does not increase obviously with the increasing matric suction under the unsaturated condition. The matric suction is not sensitive to density changes for a high water content laterite, and that is contrary for low water content.