基质吸力对非饱和土抗剪强度影响的试验研究

Experimental Study on Effect of Matrix Suction on Shear Strength of Unsaturated Soil

在非饱和土条件下产生的负孔隙水压力(基质吸力)对于预测如边坡、挡土墙、挖方工程、基础工程之类的土石结构的稳定性十分重要.为了探讨基质吸力对非饱和土抗剪强度的影响,采用非饱和土固结排水三轴剪切试验对此进行了研究.试验采用恒定的净周围压力和变化的基质吸力,以反映基质吸力的变化对抗剪强度的影响.通过对试验结果的分析可以得到如下的结论:表示基质吸力对抗剪强度的平均增加率的参数Φb为20.7°,在较小的基质吸力范围内基质吸力与抗剪强度之间存在着线性关系.

Unsaturated soil condition which give rise to negative pore pressure is important in evaluating the stability of geotechnical structures such as slopes, retaining walls, excavations and foundations. The shear strength characteristics of soil samples were investigated using consolidated drained triaxial tests with special emphasis on the effects of the matrix suction. In order to reflect the effect of matrix suction on the shear strength, the tests used shearing under a constant net confining pressure and varying matrix suctions. The results of tests were analyzed and a linear relationship was found that the relationship between matrix suction and shear strength, Φ^b, the angle indicating the rate of increase in shear strength related to matrix suction, was 20.7°.