|
|
Study on pull-out force in taproot by indoor test |
YANG Wenda1,2, WANG Guiyao1, CHANG Jingmei1, ZHANG Yongjie1 |
1. College of Civil Engineering & Architecture, Changsha University of Science & Technology, 410114, Changsha, China; 2. Home-Broad Homes Industrial International Co., Ltd., 410000, Changsha, China |
|
|
Abstract [Background] The deep anchoring effect of trees taproot and shrubs taproot on soil of slope can significantly improve the stability of slope. But in the rainfall conditions, whether the plant can play a favorable role in the stabilization of slope is controversial. Therefore, this has caused obstacles to judgement of pull-out force of taproot in rainfall conditions. [Methods] To study the factors that affect the pull-out force of taproot, the Symplocos sumuntia taproot was selected as the research object in this paper, and was used to study on the problem of pull-out force of taproot. Among them, pull-out tests were carried out under 4 soil water content conditions(10%,15%,20%,and 25%) and 3 vertical stress conditions(3.06 kPa,6.13 kPa,and 9.19 kPa), and pull-out tests contains two parts:single pull-out test and cyclic pull-out test. The pull-out test device was designed as in Figure 2 by our own laboratory. [Results] 1)The taproot pull-out force increased with the increase of stress on the taproot surface and gradually became stable. The single pull-out test results showed that, taking soil water content of 11.74% of the situation as an example, when the vertical stress was 3.06 kPa, 6.13 kPa and 9.19 kPa, the taproot average pull-out stress was 42.61 Pa, 71.52 Pa and 91.36 Pa. 2) With the increase of soil water content, the taproot pull-out force increased firstly and then decreased. The single pull-out test results showed that, taking vertical stress of 3.06 kPa of the situation as an example, when the soil water content was 11.74%, 16.02%, 21.11% and 26.53%, the taproot average pull-out stress was 42.61 Pa, 61.79 Pa, 70.35 Pa and 63.11 Pa. 3) When the soil was clay, the corresponding soil water content of the greatest pull-out force of Symplocos sumuntia taproot was 22%. 4) In the low state of stress, taproot external organizational integrity had a greater effect on the pull-out force; while in the high state of stress, taproot internal organizational integrity had a greater effect on the pull-out force. Taking soil water content of 16% of the situation as an example, when the vertical stress was 3.06 kPa and 9.19 kPa, the average pull-out stress obtained by the cyclic pull-out test was 40.79 Pa and 101.03 Pa. And the average pull-out stress obtained by the single pull-out test was 61.79 Pa and 109.01 Pa. [Conclusions] Experiments show that the soil properties and water content, root surface stress and integrity will have a significant effect on the pull-out force of taproot. And, as long as the soil water content does not exceed the optimal value, the anchoring effect of the taproot will be fully exerted.
|
Received: 27 March 2017
|
|
|
|
|
[1] |
刘志明,李建中,张可能,等. 公路边坡工程中的植物生态防护技术[J]. 地下空间与工程学报,2005,1(7):1025. LIU Zhiming, LI Jianzhong, ZHANG Keneng, et al. Technology of biological protection in the slope engineering of the highway[J]. Chinese Journal of Underground Space and Engineering, 2005, 1(7):1025.
|
[2] |
刘向东, 吴钦孝, 赵鸿雁. 森林植被垂直截留作用与水土保持[J]. 水土保持研究, 1994, 1(3):8. LIU Xiangdong, WU Qinxiao, ZHAO Hongyan. The vertical interception function of forest vegetation and soil and water conservation[J]. Research of Soil and Water Conservation, 1994, 1(3):8.
|
[3] |
徐则民, 黄润秋, 唐正光, 等. 植被护坡的局限性及其对深层滑坡孕育的贡献[J]. 岩石力学与工程学报, 2005, 24(3):438. XU Zemin, HUANG Runqiu, TANG Zhengguang, et al. Limitations of biotechnical slope protection and contribution of vegetation to deep seated landslide preparation[J]. Chinese Journal of Rock Mechanics and Engineering, 2005, 24(3):438.
|
[4] |
宋维峰, 陈丽华, 刘秀萍. 林木根系固土的理论基础[J]. 水土保持通报, 2008, 28(6):180. SONG Weifeng, CHEN Lihua, LIU Xiuping. Review of theories of soil reinforcement by root system in forest[J]. Bulletin of Soil and Water Conservation, 2008, 26(6):180.
|
[5] |
胡夏篙, 李国荣, 朱海丽, 等. 寒旱环境灌木植物根-土相互作用及其护坡力学效应[J]. 岩石力学与工程学报, 2009, 28(3):613. HU Xiasong, LI Guorong, ZHU Haili, et al. Research on interaction between vegetation root and soil for slope protection and its mechanical effect in cold and arid environments[J]. Chinese Journal of Rock Mechanics and Engineering, 2009, 28(3):613.
|
[6] |
曹云生, 陈丽华, 盖小刚, 等. 油松根系的固土力学机制[J]. 水土保持通报, 2014, 34(5):6. CAO Yunsheng, CHEN Lihua, GAI Xiaogang, et al. Soil reinforcement by Pinus tabuliformis roots[J]. Bulletin of Soil and Water Conservation, 2014, 34(5):6.
|
[7] |
韩立亮,宋桂龙. 护坡木本植物根系的力学特性及其与细胞壁成分的关系[J]. 北京林业大学学报,2015,37(11):120. HAN Liliang, SONG Guilong. Relationship between root mechanical characteristics and cell wall components of woody plant species[J]. Journal of Beijing Forestry University,2015,37(11):120.
|
[8] |
夏振尧,管世烽,牛鹏辉,等. 麦冬和多花木蓝根系抗拉拔特性试验研究[J]. 水土保持通报,2015,35(6):110. XIA Zhenyao, GUAN Shifeng, NIU Penghui, et al. Experimental study on pull-out resistive properties of Ophoipogon japonicas and Indigofera amblyantha roots[J]. Bulletin of Soil and Water Conservation,2015,35(6):110.
|
[9] |
曹云生,陈丽华,刘小光,等. 植物根土界面摩擦力的影响因素研究[J]. 摩擦学学报,2014,34(5):482. CAO Yunsheng, CHEN Lihua, LIU Xiaoguang, et al. The influence factors of plant root-soil interface friction[J]. Tribology,2014,34(5):482.
|
[10] |
邢会文,刘静,王林和,等. 柠条、沙柳根与土及土与土界面摩擦特性[J]. 摩擦学学报,2010,30(1):87. XING Huiwen, LIU Jing, WANG Linhe, et al. Friction characteristics of soil-soil interface and root-soil interface of Caragana intermedia and Salix pasammophila[J]. Tribology,2010,30(1):87.
|
[11] |
格日乐,张成福,蒙仲举,等. 3种植物根-土复合体抗剪特性对比分析[J]. 水土保持学报,2014,28(2):85. GE Rile, ZHANG Chengfu, MENG Zongju, et al. The shear property comparison of three roots-soil composites[J]. Journal of Soil and Water Conservation,2014,28(2):85.
|
[12] |
宋维峰,陈丽华,刘秀萍. 根系与土体接触面相互作用特性试验[J]. 中国水土保持科学,2006,4(2):62. SONG Weifeng, CHEN Lihua, LIU Xiuping. Experiment on characteristic of interface between root system and soil[J]. Science of Soil and Water Conservation,2006,4(2):62.
|
[13] |
张兴玲,胡夏篙,毛小青,等. 青藏高原东北部黄土区护坡灌木柠条锦鸡儿根系拉拔摩擦试验研究[J]. 岩石力学与工程学报,2011,30(S2):3739. ZHANG Xingling, HU Xiasong, MAO Xiaoqing, et al. Research on pull-out friction test of shrub Caragana korshinskii roots for slope protection in loess area of Northeast Qinghai-Tibetan Plateau[J]. Chinese Journal of Rock Mechanics and Engineering,2011,30(S2):3739.
|
|
|
|