植物根系拉拔模型试验研究

发布时间：2018-05-19 12:06

本文选题：根系拉拔 + 模型试验　；参考：《西南交通大学》2015年硕士论文

【摘要】：植物护坡作为一种新型的护坡技术,近年来得到了广泛的研究。目前大多研究以根-土复合体的抗剪为出发点,以细根高强度为理论基础,得出根系的存在对土体抗剪强度的提高值。而实际工程中,滑坡发生时,细根容易达到抗拉强度而被拉断,起到固土作用的往往是刚度较大的粗根。本文通过开展植物根系拉拔模型试验研究,研究粗根系与土体之间相互作用机制,分析了根系长度、形态、荷载方向等对根系抗拔性能的影响,并将试验结果与理论计算结果进行了对比分析,得到了以下的结论和成果：1.在埋深0～80cm的范围内,竖直单根在竖向荷载作用下,根侧摩阻力随埋深的增大呈现出先增大后减小的趋势,侧摩阻力最大值出现在0.3～0.5倍根长处,埋深20～60cm的深度内,根侧摩阻力较大,在根的抗拔作用中占主要部分；2.对竖直单根而言,荷载方向一定时,随着单根长度的增大,单根的极限荷载值增大；当单根长度一定时,随着荷载方向与竖向间夹角的增大,单根极限荷载值增大；3.对含单一侧根的根系,在竖向荷载作用下,主、侧根长度一定时,随着侧根与竖向间夹角的增大,根系整体的抗拔力增大,侧根的存在大大提高了根系整体的抗拔力；4.对含两对称侧根的根系,在竖向荷载作用下,当侧根长度、夹角θ不变时,随着主根长度的增大,根系整体的极限荷载值增大；当主根、侧根长度相等时,根系极限荷载随θ的增大而增大；5.当根系总长度一定时,根系形态是影响根系整体抗拔能力的主要因素,根系形态越复杂,根系抗拔力越大。
[Abstract]:As a new slope protection technology, plant slope protection has been widely studied in recent years. At present, most of the researches are based on the shear resistance of root-soil complex and the high strength of fine root, and the increase of soil shear strength caused by the existence of root system is obtained. However, in the actual engineering, the fine root is easy to reach tensile strength and be broken when the landslide occurs, and it is often the thick root with large stiffness that plays the role of soil consolidation. In this paper, the effects of root length, shape and load direction on the root resistance were studied by studying the mechanism of the interaction between coarse root system and soil mass through the experimental research on the pull-out model of plant root system, and the effects of root length, shape and load direction on the root resistance were analyzed. The experimental results are compared with the theoretical results, and the following conclusions and results: 1. 1 are obtained. In the range of buried depth 0~80cm, vertical single root under vertical load, the root side friction increases first and then decreases with the increase of buried depth, the maximum of side friction appears in 0.3n0. 5 times of root strength, and the depth of buried depth 20~60cm, the maximum value of side friction appears in the depth of 20~60cm. The friction resistance of the root side is great, which is the main part of the root anti-pullout action. For vertical single root, when the load direction is constant, the limit load value of single root increases with the increase of the length of single root, and with the increase of the angle between load direction and vertical direction when the length of single root is fixed, the limit load value of single root increases by 3%. For the root system with one side root, under the action of vertical load, with the increase of the angle between lateral root and vertical root, when the length of main and lateral root is fixed, the whole pullout resistance of root system increases, and the exiting of lateral root greatly improves the whole pullout resistance of root system. For the root system with two symmetrical lateral roots, when the lateral root length and angle 胃 are constant, the limit load value of the root system increases with the increase of the main root length, and when the main root length is equal, the lateral root length is equal. The root limit load increases with the increase of 胃. When the total length of the root system was fixed, the root morphology was the main factor affecting the overall resistance of the root system. The more complex the root morphology, the greater the resistance of the root system.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：Q947;TU43

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