【摘要】：近年來(lái)我國(guó)經(jīng)濟(jì)發(fā)展迅速,全國(guó)各地大興土木,投入的基礎(chǔ)設(shè)施建設(shè)非常大。大量的基礎(chǔ)設(shè)施建設(shè),對(duì)人們生活提供了方便也提高了生活質(zhì)量,但是對(duì)自然界中原有生態(tài)環(huán)境造成了影響。特別是在山區(qū)和丘陵地帶建設(shè)高速公路、鐵路等大型基礎(chǔ)設(shè)施,無(wú)可避免的進(jìn)行高填深挖,對(duì)原有植物和土體結(jié)構(gòu)造成破壞,有的甚至還造成了裸露的邊坡。部分人工邊坡有存在安全隱患,如坍塌、侵蝕、滑坡等,更嚴(yán)重的還會(huì)出現(xiàn)破壞生物鏈和水土流失等環(huán)境問題。傳統(tǒng)的工程防護(hù)措施比較成熟,能較好地加固人工邊坡,但也存在不足,因?yàn)閭鹘y(tǒng)工程防護(hù)完全封閉了植被生長(zhǎng),這對(duì)可持續(xù)發(fā)展以及環(huán)境保護(hù)不利。相對(duì)于傳統(tǒng)邊坡護(hù)坡技術(shù),植被護(hù)坡技術(shù)有更多的優(yōu)勢(shì),如景觀效果好、工程造價(jià)低以及服務(wù)年限長(zhǎng)。邊坡生態(tài)防護(hù)逐步得到了推廣運(yùn)用,在高速公路、水利水電、鐵路等工程的坡面防護(hù)中廣泛運(yùn)用。在邊坡生態(tài)防護(hù)的研究領(lǐng)域中根系固土力學(xué)機(jī)理有較廣泛的關(guān)注,也是研究的熱點(diǎn)問題。在國(guó)內(nèi)外已有研究基礎(chǔ)之上,本論文以狗牙根和馬尼拉草以及長(zhǎng)沙本地黏性土組成的根土復(fù)合體作為研究對(duì)象,依托長(zhǎng)沙市科技計(jì)劃項(xiàng)目“長(zhǎng)沙市公路路域生態(tài)恢復(fù)技術(shù)及推廣研究”(項(xiàng)目號(hào)：K1205028-11)和中南林業(yè)科技大學(xué)科研究生技創(chuàng)新基金(項(xiàng)目號(hào)：CX2013Z41)等開展相關(guān)研究,所做的主要工作和取得的主要結(jié)論如下：1、在長(zhǎng)沙市的市政公路邊坡進(jìn)行現(xiàn)場(chǎng)調(diào)研,研究了狗牙根和馬尼拉草的生長(zhǎng)狀況以及根系的分布形態(tài)與密度。得出了根系密度隨土層深度的增加而減小的規(guī)律,并且得出了函數(shù)關(guān)系。2、通過對(duì)不同根密度的根土復(fù)合體的直剪試驗(yàn),得出抗剪強(qiáng)度和含根量的關(guān)系,以及提出了兩種草本植物根土復(fù)合體的黏聚力和內(nèi)摩擦角與含根量的函數(shù)關(guān)系,計(jì)算結(jié)果和實(shí)測(cè)數(shù)據(jù)非常吻合,并得到了以下結(jié)論：(1)垂直應(yīng)力影響剪切強(qiáng)度,垂直應(yīng)力和根土復(fù)合體的抗剪強(qiáng)度呈線性關(guān)系。隨著垂直應(yīng)力的增大,抗剪強(qiáng)度呈線性增加。(2)根含量影響土體的剪切強(qiáng)度,根土復(fù)合體的的抗剪強(qiáng)度隨著根數(shù)的增加而增強(qiáng),但隨著根數(shù)的增加,抗剪強(qiáng)度的增幅逐漸減小。(3)根對(duì)土體的內(nèi)摩擦角的影響不大,但是黏聚力增加明顯,這相當(dāng)于通過根來(lái)增加凝聚力從而提高土體的抗剪強(qiáng)度。(4)根土復(fù)合體的剪切強(qiáng)度與土的含水量也有關(guān)系。含水率越低,抗剪強(qiáng)度越大；在含水率較低時(shí)根對(duì)土體的抗剪強(qiáng)度有較大提高,即根對(duì)土體抗剪切度貢獻(xiàn)大。(5)在兩種含水率的情況下,狗牙根的根土復(fù)合體抗剪強(qiáng)度增幅值大于尼拉根土復(fù)合體抗剪強(qiáng)度增幅值。(6)提出了兩種草本植物根土復(fù)合體的黏聚力和內(nèi)摩擦角與含根量的函數(shù)關(guān)系,其中黏聚力與含根量呈對(duì)數(shù)函數(shù)規(guī)律變化,內(nèi)摩擦角與含根量呈線性函數(shù)規(guī)律變化。3、根據(jù)道路的邊坡情況,通過瑞典條分法研究了狗牙根和馬尼拉草不同根密度的邊坡穩(wěn)定系數(shù),根密度越大其邊坡的穩(wěn)定系數(shù)也越大,并且得出了根密度與穩(wěn)定系數(shù)的函數(shù)關(guān)系。
[Abstract]:In recent years, the economic development of our country has been developing rapidly, and the construction of the infrastructure that has been invested in the whole country is very large. The construction of a large amount of infrastructure has provided a convenient and improved quality of life for people, but has an impact on the ecological environment in the natural world. In particular, a large-scale infrastructure, such as a highway, a railway and the like, is built in a mountain area and a hilly area, so that the high-filling and deep-excavation can be avoided, and the damage to the original plant and the soil body structure is avoided, and the exposed side slope is even caused. Some artificial side slope has potential safety hazard, such as collapse, erosion, landslide, and more serious environmental problems such as biological chain and water and soil loss. The traditional engineering protection measures are relatively mature, can better reinforce the artificial side slope, but also have insufficient, because the traditional engineering protection completely closed the vegetation growth, which is unfavorable to the sustainable development and the environmental protection. Compared with the traditional slope protection technology, the vegetation slope protection technology has more advantages, such as good landscape effect, low engineering cost and long service life. The slope ecological protection has been widely used in the slope protection of the highway, water conservancy and hydropower, railway and other projects. In the research field of slope ecological protection, the mechanism of root-fixing soil mechanics has a wide range of attention, and it is also a hot issue of research. Based on the existing research, this paper takes the root and soil complex of the root of the dog and the grass of manila and the local cohesive soil of Changsha as the research object, and relies on the "Study on the Technology and Promotion of the Ecological Restoration of the Road and Road in Changsha" of the project of Changsha Science and Technology Plan (Project No.: K1205028-11) and the Science and Technology Innovation Fund (Project No.: CX2013Z41) in Central and South Forestry Science and Technology, and other relevant research, the main work and main conclusions are as follows:1. On-site investigation of the municipal highway slope in Changsha, The growth of root and manila grass and the distribution and density of root system were studied. The relationship between the shear strength and the root content is obtained by the direct shear test of the root soil complex with different root density. The cohesion and internal friction angle of the two kinds of herbaceous plant root-soil complex and the function relation of the internal friction angle and the root-containing quantity are proposed, and the calculation results and the measured data are in good agreement, and the following conclusions are obtained: (1) the vertical stress affects the shear strength, The shear strength of the vertical stress and the root-soil complex is linear. With the increase of the vertical stress, the shear strength increases linearly. (2) The root content affects the shear strength of the soil, and the shear strength of the root-soil complex increases with the increase of the number, but with the increase of the number, the increase of the shear strength is gradually reduced. (3) The influence of the root on the internal friction angle of the soil is not small, but the cohesion is obviously increased, which is equivalent to the increase of the cohesion through the root, so as to improve the shear strength of the soil. (4) The shear strength of the root soil complex is also related to the water content of the soil. The lower the water content, the greater the shear strength; when the water content is low, the shear strength of the root to the soil is greatly improved, that is, the root has great contribution to the shear strength of the soil body. (5) In the case of two water content, the shear strength increase of the root-soil composite of the root of the dog is greater than the increase of the shear strength of the composite soil. (6) The cohesion and the internal friction angle and the root-containing function relation of the root-soil complex of the two kinds of herbaceous plants are put forward, in which the cohesive force and the root-containing amount change regularly, the internal friction angle and the root-containing amount are in linear function, and 3, according to the slope of the road, The stability coefficient of the slope with different root density of the root of the dog and the manila grass is studied by the Swedish method. The higher the root density and the stability coefficient of the slope are obtained, and the function relation between the root density and the stability coefficient is obtained.
【學(xué)位授予單位】：中南林業(yè)科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U417.12

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本文編號(hào)：2464152