非饱和土湿吸力与含水率的定量关系研究

Quantitative relationship between wet suction and water content of unsaturated soils

以立方松散堆积方式为例,从理论上推导并给出了湿吸力与非饱和土含水率的定量关系表达式,开展了不同含水率状态下重塑细粒砂性土的吸力测试,对试验结果进行了曲线拟合和分析,理论计算和试验拟合结果均表明:对于特定的非饱和土,湿吸力随含水率先增大而后减小,即存在确定的界限含水率。这与"在一定的土体含水率变化范围内,非饱和土,尤其是非饱和砂性土的强度随含水率的增加而先增大后减小"的事实完全相符,这再次证明了湿吸力,而非基质吸力,才是非饱和土有效应力的重要组成部分。

Based on the example of cubic loose accumulation, a quantitative relation expression is deduced theoretically between wet suction and water content of unsaturated soils. The suction tests on remodeling fine grain sand soil with different water content are carried out, and a curve-fitting of the test results is analyzed. Theoretical calculations and experimental results show that for specific unsaturated soils, with the increase of the water content, the suction wet increases first and then decreases, which is the same as that when there is a certain boundary of water content. This agrees with the fact that in a certain range, the strength of the unsaturated soils, especially the unsaturated sand soils, increases first and then decreases with the increase of the water content. It indicates that the wet suction, instead of matrix suction, is the important part of effective stress.