斥水红黏土的增湿强度特性研究

在红黏土中加入十八胺使其由亲水变为斥水,分别对亲水和斥水土进行不同容重下增湿和不增湿直剪试验,通过试验对不增湿条件下红黏土由亲水变为斥水后的抗剪强度变化规律及增湿对亲水和斥水红黏土抗剪强度的影响展开研究.试验结果表明:不增湿条件下,亲水土壤变为斥水后其强度会降低,且随着正应力的增大斥水土壤抗剪强度降低越明显;增湿对亲水...

Study on Wetting Strength Characteristics of Water Repellency Red Clay

Repellent soil reduces water infiltration and thereby affects crop growth. Such characteristic is widely accepted as a disadvantage of repellent soil. However, repellent soil can maintain its unsaturated state and strength through reduction and even prevention of rain infiltration, which are conducive to the stability of soil structure from the perspective of engineering geology. In this study, octadecylamine was added into red clay to change its state from hydrophilic into repellent. Direct shear tests on hydrophilic and repellent soils with and without wetting were carried out under different dry densities. Moreover, the variation rules in the shear strength of red clay without wetting during the transition from hydrophilic soil to repellent soil were investigated. The influences of wetting on the shear strengths of hydrophilic and repellent soils were tested. Results demonstrate that shear strength of repellent soil without wetting is lower compared with that of hydrophilic soil and that such reduction amplitude increases with the increase in normal stress. Wetting considerably influences the shear strength of hydrophilic soil but only slightly affects that of repellent soil. The shear strengths of both hydrophilic and repellent soils increase with the increase in dry density. The influences of wetting on hydrophilic and repellent soils are related to dry density and normal stress. Thus, comprehensive considerations should be given to the dry density and stress state of soils when improving the shear strength of wetting soils based on the characteristics of repellent soils.