Indoor experimental study on the pull-out force of Symplocos anomala Brand root
ZHANG Wenhao1, WANG Guiyao1, HU Shenghui1,2, ZHANG Yongjie1, QUAN Peng1,3, CHANG Jingmei1
1. School of Civil Engineering, Changsha University of Science and Technology, 410014, Changsha, China; 2. Guangxi Road and Bridge Engineering Group Co. Ltd., 530011, Nanning, China; 3. Hunan Labor and Human Resources Vocational College, 410100, Changsha, China
Abstract：[Background] Arbor and shrubs are common plants in vegetation slope protection in southern red clay, their roots are thicker and the roots grow deeper. Both the horizontal and vertical roots at the landslide zone act like anchors. Therefore, the interaction between roots of arbors and shrubs and deep soil is of great significance for slope ecological protection.[Methods] The experiment was carried out by controlling the geometric parameters of the root and the overlying load. The single root was buried horizontally in the center of the cube test box. The soil was laminated in two layers with a compactness of 90%. The upper part of the cube test box was used for loading. The reserved root was held by a modified HP-50 Handpi digital push-pull test device (the test tensile speed was controlled at 3 mm/s), and the pull-out device was connected to a computer to directly obtain the pull-out force data.[Results] 1) The maximum pull-out force of S. anomala roots increased with the increase of the root radius r, length L, and root-soil contact area; when the root appeared to be pulled out and damaged, the pull-out force per unit area of the root increased with the increase of the root radius r, and decreased with the increase of root length L. 2) In the presence of fibrous roots, the maximum pull-out force of the root increased from 48.2 N to 55.3 N, indicating that the presence of the fibrous roots increased the maximum pull-out force of the root. 3) The maximum pull-out force was 16.4 N when the load was 0 kPa; the maximum pull-out force was 22.2 N when the load was 3.125 kPa; and the maximum pull-out force was 26.9 N when the load was 6.250 kPa. This showed that the larger the overlying load was, the greater the increment of friction between the root and soil was. 4) By fitting and analyzing the experimental data, the friction angle decreased with the increase of L, r, and the root-soil contact area. The cohesive force decreased with the L increasing, while increased with r or the root-soil contact area increasing. The correlation between the root friction coefficient and the root-soil contact area was not significant.[Conculsions] Through the indoor pull-out test, the root-soil interaction forces of the S. anomala Brand root under different geometrical parameters, different overlying loads, and the presence or absence of fibrous roots are explored. The test results present certain regularity and provide an effective experimental basis for soil consolidation effect of slope protection by vegetation.
张文豪, 王桂尧, 胡圣辉, 张永杰, 全鹏, 常婧美. 薄叶山矾根系抗拔力的室内试验研究[J]. 中国水土保持科学, 2020, 18(3): 22-30.
ZHANG Wenhao, WANG Guiyao, HU Shenghui, ZHANG Yongjie, QUAN Peng, CHANG Jingmei. Indoor experimental study on the pull-out force of Symplocos anomala Brand root. SSWC, 2020, 18(3): 22-30.
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2020, Vol. 18 
