颗粒级配对非饱和粘性土基质吸力的影响规律

Effect of particle size distribution on the metric suction of unsaturated clayey soils

颗粒级配是影响非饱和粘性土基质吸力变化规律的主要因素之一。本文在室内实验基础上,根据颗粒级配与非饱和土土水特征曲线基本参数之间的定量关系,探讨了颗粒级配对非饱和土基本特性的影响程度。研究结果表明:颗粒级配对非饱和土残余含水量控制作用明显,后者与粘粒、粉粒含量线性正相关,与角砾含量和粗、细粒含量之比分别线性、非线性负相关;不同粒组中,粉粒含量对土体残余含水量的影响程度最大,角砾含量的影响程度较低。颗粒级配对非饱和土残余基质吸力的影响程度较弱,后者与粘粒含量以及粗、细粒含量之比具有一定的相关性。非饱和土含水量变化幅度以及基质吸力对含量变化的敏感性与颗粒级配相关性最弱。但是,粘粒、粉粒含量以及粗、细粒含量之比对这两个特征值可能具有一定的影响作用。

Particle size distribution （PSD） is unsaturated soils. Effect of PSD on the metric one of the factors influencing variation of metric suction of unsaturated clayey soils was investigated suction occurred in in this paper based on soil water characteristic curves （SWCC） obtained in laboratory. PSD＇s such effect was described using its various correlations with the parameters of SWCC. It was found that PSD has strong influence on residual water content of the unsaturated soils. Specifically, residual water content has a very close liner correlation with clay and silt content, a fairly closed reverse liner correlation with gravel content, and a reverse non-liner correlation with the ration of coarse to fine fraction content. Among size fractions influencing residual water content, it seems that silt fraction is the strongest, and gravel fraction is the weakest. PSD effect on residual metric suction of the unsaturated soils is weaker than that on residual water content. But, it seems that clay fraction and the ratio of coarse to fine fraction content has some effects on residual metric suction. PSD has the weakest effect on the two parameters of the unsaturated soils： the difference between saturated and residual water content, and sensitivity of metric suction to water content. However, it appears that clay, silt fractions and the ratio of coarse to fine fraction content may has certain effects on the two parameters.