| 退化高寒草原人工恢复植被根系及根-土复合体力学特性研究 |
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| 引用本文： | 何伟鹏,刘昌义,周国英,胡夏嵩,付江涛,卢海静,闫聪,杨馥铖,李国荣.退化高寒草原人工恢复植被根系及根-土复合体力学特性研究[J].水文地质工程地质,2022,49(2):207-218. |
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| 作者姓名： | 何伟鹏 刘昌义 周国英 胡夏嵩 付江涛 卢海静 闫聪 杨馥铖 李国荣 |
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| 作者单位： | 1.青海大学地质工程系, 青海 西宁 810016 |
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| 基金项目： | 青海省自然科学基金项目（2020-ZJ-906;2018-ZJ-781）；;国家自然科学基金项目（42041006;41572306）； |
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| 摘 要： | 为研究人工恢复草本植物对青藏铁路沿线退化高寒草原土体抗剪强度增强作用，以青藏铁路沱沱河段人工草地建植区为研究区，通过对区内生长期为1 a的3种组合种植草本植物开展单根拉伸和根-土复合体直剪试验，评价了3种草本组合单根、根-土复合体力学强度特性。研究结果表明:组合类型I即扁穗冰草（Agropyron cristatum）+碱茅（Puccinellia distans）+冷地早熟禾（Poa crymophila），其3种草本平均根径（0.06～0.34 mm）、平均抗拉力（0.58～3.09 N）、平均抗拉强度（36.87~221.70 MPa）相对最大；3种草本组合其单根抗拉力与根径呈幂函数正相关关系，而抗拉强度与根径呈幂函数负相关关系；直剪试验结果表明，3种草本组合其根-土复合体黏聚力均随深度增加而降低，其中组合类型I其根-土复合体黏聚力相对最大为32.62 kPa，且较组合类型II、组合类型III根-土复合体黏聚力的增加幅度分别为15.3 %、57.7 %，表现出草本组合类型I具有相对更为显著的增强土体抗剪强度作用。研究结果可为青藏铁路沿线高寒草地退化、水土流失、浅层滑坡等灾害防治提供理论依据，同时对采用种植植被开展沿线生态恢复具有实际指导意义。
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| 关 键 词： | 青藏铁路 人工恢复草地 单根抗拉强度 根-土复合体 抗剪强度 |
| 收稿时间： | 2021-08-25 |
A study of the mechanical properties of herbaceous roots and root-soil composite systems in the degraded alpine pasture artificially restored grassland |
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| Affiliation: | 1.Department of Geological Engineering, Qinghai University, Xining, Qinghai 810016, China2.Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China3.Academy of Agriculture and Forestry, Qinghai University, Xining, Qinghai 810016, China4.College of Agriculture and Animal Husbandry, Qinghai University, Xining, Qinghai 810016, China |
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| Abstract: | To study the reinforcement to soil by herb roots along the Qinghai-Tibet railway, an artificially restored grassland along the Qinghai-Tibet railway is selected as test site. By conducting tensile tests to a single root and direct shear tests to the root-soil composite system with its growth period of one year, such mechanical indices as roots’ tensile strength and shear strength of root-soil composite system are quantitatively assessed. The results show that the values of the mean root diameter, tensile resistance and tensile strength for the combination I (Agropyron cristatum + Puccinellia distans + Poa crymophila) are greater than those for the other combinations. Moreover, a positive power function can be introduced to describe the relationship between the root diameter and its tensile resistance for the three species, while a negative power function is introduced to describe the relationship between the root diameter and its tensile strength. In addition, the cohesion of the root-soil composite system for the three species exhibits a decreasing trend with the increasing soil depth. Of the values for cohesion for the three species, the cohesion for the combination I is 32.62 kPa, greater than that of the other two combinations by 15.3 % and 57.7%, respectively, suggesting the excellent capacity in reinforcing soil. The results may provide a theoretical basis for the prevention and control of the alpine grassland degradation, soil erosion, shallow landslides and other geo-hazards and eco-hazards along the Qinghai-Tibet railway, and are of a practical guiding significance for ecological restoration by planting vegetation along the railway. |
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