Research on Direct Shear Test of Undisturbed Root-soil Composition

摘要

In order to further study the soil reinforcement of roots on the quantitative analysis of "reinforced" soil, to understand the effect of plant roots on the soil shear strength, direct shear test was employed to investigate the shear displacement and stress force relationship of the undisturbed soil and disturbed soil without root located at An Shan Kou, Ba Mao Di, Hun He Di and Duo Hua Mulan Di and the shear strength of the average root content of soil was discussed, as well. The results show that the cohesion of the undisturbed soil is significantly greater than that of the disturbed soil without root, under the condition of the average root content of 0.945% at An Shankou, 1.154% at Ba Mao Di, 0.4425% at Hun He Di, 1.1725% at Duo Hua Mulan Di. The increase of cohesion is respectively 5.05, 17.19, 36.93, 31.84%; and the increase of inner friction angle is not obvious with the increase of root content, soil cohesion increase, the shear strength thus increases. Compared with the herbaceous roots, the grass-shrub mixed plant roots system can improve the shear strength of the soil more effectively.