不同饱和度下黏粒含量对土体强度特性的影响

Influence of Clay Contents on Soil Strength Property under Different Degrees of Saturation

通过对山东东明某风电场细粒土进行不同饱和度、不同黏粒含量的直剪试验,研究了土体剪应力-剪切位移关系及抗剪强度的变化规律。结果表明:细粒土在低饱和度下的剪应力-剪切位移关系呈应变软化,脆性破坏;高饱和度下呈应变硬化,塑性破坏;且土体内黏粒含量越多,剪应力-剪切位移曲线的应变软化行为越弱,应变硬化现象发生得越早;粉土随着饱和度的增加,抗剪强度持续下降无峰值,明显受黏聚力影响;粉质黏土和黏土随饱和度的增加,抗剪强度表现出先升后降的特点,受内摩擦角影响加大;细粒土中黏粒含量不同,土体抗剪强度受饱和度影响的程度和形式便不同。

In this paper, direct shear tests were performed to study the influence of various degrees of saturation and clay contents on the shear strength of soil samples collected from a wind farm in Shandong Province. The test results showed that the shear stress-shear displacement relationship under the condition of a low degree of saturation was strain softening, and the strain hardening under a high degree of saturation. In addition to this, the plasticity of the cohesive soil sample increases with the increase in clay contents. With the increase in the degree of saturation, the cohesive forces among soil particles decrease which results in the decrease in shear strength of silty soil samples. Further, with the increase in clay contents, the shear strength of silty soil samples at first increases and then decreases, which is affected by the angle of internal friction. Overall, the clay content is an important factor that controls the effect of degree of saturation on the shear strength of fine-grained soils.