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| In-situ shearing test on the shear strengh of soil slope reinforced by plant roots in cold and arid environments |
| LU Haijing1,2,HU Xiasong1,3,FU Jiangtao3,LI Guorong1,ZHAO Yujiao1,LI Huatan1,ZHU Haili1,LIU Changyi1 |
| (1. Geological Engineering Department,Qinghai University,Xining,Qinghai 810016,China;2. School of Mechanical Engineering,Qinghai University,Xining,Qinghai 810016,China;3. Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining,Qinghai 810008,China) |
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Abstract Xining basin and the surrounding area were selected as the experimental zone. 2 herbs-Elymus dahuricus and Agropyron trachycaulum and 2 shrubs-Caragana korshinskii and Zygophyllum xanthoxylon,had been growing on the slope with the angle of 30° for 150 days. In-situ shear tests were conducted to estimate the contribution of plant roots in enhancing shear strength of soil in two scenarios,the herbs only or shrubs only planting and the mixture of herbs and shrubs planting. On this basis,Wu-Waldron-Model(WWM) was used to evaluate the effects of both the single planting and mixed planting of herbs and shrubs in reinforcing the slope soil. The values calculated with WWM and from in-situ shear tests were compared. The results of in-situ shear tests on the root-soil composite systems showed that the shear strength of the samples of root-soil composite system improved more significantly than the samples of soil without roots. The shear strength of the root-soil composite systems with monoculture herb or shrub increased from 47.61% to 98.24%,and the shear strength of root-soil composite systems with mixed herbs and shrubs increased from 104.47% to 173.93%,indicating that the effect of reinforcement of the mixed planting of herbs and shrubs are better than that of monoculture. Under two kinds of planting forms (single planting and mixed planting),the shear strength of root-soil composite systems from WWM model and in-situ shear test are basically consistent.
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