黏粒含量对黏性土渗透性影响的试验研究

渗透性是土体的重要工程性质之一,在诸如垃圾填埋场防污、水利大坝防渗、基坑支护防漏等工程项目中,运用各种方法提高土体的抗渗性是施工的最终目的。基于此,制备不同黏粒含量的黏性土试样;并开展渗透及相关试验,以分析黏粒含量对渗透性的影响。试验结果表明随着黏粒含量的增加,黏性土的塑性指数呈线性增加,而渗透系数呈非线性减小,可用指数函数式拟合。另外,颗分曲线显示高黏粒含量试样的不均匀系数变小,其堆积方式以小粒径颗粒接触为主,孔隙通道直径小,易出现不连通孔隙,导致渗透系数减小,所得成果可供工程实践参考。

Experimental study on effect of clay content on permeability of clayey soil

Permeability is an important property of soil. For the project such as the anti-pollution of the landfill, the seepage control of the dam and the leakage control of the foundation pit, the ultimate aim is to improve the impermeability of soil by various methods. Therefore, the clayey soil samples with different clay content were prepared and used for the permeability and related tests. The influence of clay content on the permeability can be analyzed by above tests. The results show that with the increase of clay content, the plasticity index of clayey soil increases linearly, while the permeability coefficient decreases nonlinearly which can be fitted by exponential function. According to the grain graduation curves, the samples with high clay content have small non-uniformity coefficient. It implies that the soil accumulation mode dominated by small particles, which makes pore diameter small and easy to appear disconnected pores. So the permeability coefficient of soil decreases. The results can be used for engineering practice.