發(fā)布時間：2018-05-19 12:06

  本文選題：根系拉拔 + 模型試驗��； 參考：《西南交通大學(xué)》2015年碩士論文

【摘要】：植物護(hù)坡作為一種新型的護(hù)坡技術(shù),近年來得到了廣泛的研究。目前大多研究以根-土復(fù)合體的抗剪為出發(fā)點,以細(xì)根高強度為理論基礎(chǔ),得出根系的存在對土體抗剪強度的提高值。而實際工程中,滑坡發(fā)生時,細(xì)根容易達(dá)到抗拉強度而被拉斷,起到固土作用的往往是剛度較大的粗根。本文通過開展植物根系拉拔模型試驗研究,研究粗根系與土體之間相互作用機制,分析了根系長度、形態(tài)、荷載方向等對根系抗拔性能的影響,并將試驗結(jié)果與理論計算結(jié)果進(jìn)行了對比分析,得到了以下的結(jié)論和成果：1.在埋深0～80cm的范圍內(nèi),豎直單根在豎向荷載作用下,根側(cè)摩阻力隨埋深的增大呈現(xiàn)出先增大后減小的趨勢,側(cè)摩阻力最大值出現(xiàn)在0.3～0.5倍根長處,埋深20～60cm的深度內(nèi),根側(cè)摩阻力較大,在根的抗拔作用中占主要部分；2.對豎直單根而言,荷載方向一定時,隨著單根長度的增大,單根的極限荷載值增大；當(dāng)單根長度一定時,隨著荷載方向與豎向間夾角的增大,單根極限荷載值增大；3.對含單一側(cè)根的根系,在豎向荷載作用下,主、側(cè)根長度一定時,隨著側(cè)根與豎向間夾角的增大,根系整體的抗拔力增大,側(cè)根的存在大大提高了根系整體的抗拔力；4.對含兩對稱側(cè)根的根系,在豎向荷載作用下,當(dāng)側(cè)根長度、夾角θ不變時,隨著主根長度的增大,根系整體的極限荷載值增大；當(dāng)主根、側(cè)根長度相等時,根系極限荷載隨θ的增大而增大；5.當(dāng)根系總長度一定時,根系形態(tài)是影響根系整體抗拔能力的主要因素,根系形態(tài)越復(fù)雜,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.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：Q947;TU43

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本文編號：1910033