本文選題：高速公路 + 植被護坡�。� 參考：《中南林業(yè)科技大學(xué)》2017年碩士論文

【摘要】：高速公路修筑過程中不可避免存在高填深挖,這不僅嚴重破壞當(dāng)?shù)厣鷳B(tài)環(huán)境,且容易引起水土流失、塌方、泥石流等地質(zhì)災(zāi)害,對車輛和人身安全造成了很大的威脅。傳統(tǒng)的工程護坡技術(shù)不僅工程量浩大,耗材多,造價高,形式比較單一,而且永久性的破壞了生態(tài)環(huán)境,因此,邊坡的有效治理是高速公路工程建設(shè)中亟待解決的問題。本文依托國家林業(yè)局948項目“深路塹邊坡景觀恢復(fù)關(guān)鍵技術(shù)引進”(項目編號為101-9968)和大岳高速第八合同段邊坡實體工程,以種植的多花木蘭和刺槐兩種灌木作為研究對象,通過對植物根系分布特征進行分析,對根-土復(fù)合體進行剪切和拉拔試驗,研究了植物根系的分布形態(tài)規(guī)律和根-土復(fù)合體的力學(xué)特性,研究工作的主要創(chuàng)新成果如下。1、通過植物根系形態(tài)分布研究發(fā)現(xiàn),刺槐和多花木蘭兩種灌木的根系形態(tài)存在一定的差異,刺槐的主根系作用不明顯,水平根系和其上著生出的斜根系較多,相互交織成網(wǎng)狀,有利于增強邊坡土壤的整體性,多花木蘭主根系和副根系比較發(fā)達,在護坡中主要起錨桿作用,維系邊坡的穩(wěn)定。2、通過對多花木蘭和刺槐根-土復(fù)合體室內(nèi)直剪試驗研究發(fā)現(xiàn),植物根系能有效提高土體的抗剪強度。通過對試驗數(shù)據(jù)進行分析和處理,得出根-土復(fù)合體的抗剪強度符合庫倫定律,根據(jù)庫侖定律得到多花木蘭和刺槐的黏聚力c和內(nèi)摩擦角φ;在相同條件下,多花木蘭根-土復(fù)合體的抗剪強度略大于刺槐根-土復(fù)合體抗剪強度;3、在相同條件下,混合布根方式的抗剪強度最高,全部斜交布根的抗剪強度次之,全部垂直布根的抗剪強度最小;在相同根系數(shù)量和布根方式條件下,隨著根系直徑的增大,根-土復(fù)合體的抗剪強度先增大后減小,當(dāng)根系直徑在1.0mm～1.2mm時,根-土復(fù)合體的抗剪強度達最大值。4、通過對多花木蘭和刺槐對根-土復(fù)合體進行三軸剪試驗研究,得到了不同條件下素土和根-土復(fù)合體應(yīng)力-應(yīng)變曲線;在不同圍壓和含水率條件下,當(dāng)軸向應(yīng)變小于等于2%時,無根素土和根-土復(fù)合體應(yīng)力-應(yīng)變曲線大多呈線性增加,當(dāng)軸向應(yīng)變大于2%時,主應(yīng)力差增加緩慢,試樣呈硬化破壞,最后曲線趨于平穩(wěn),主應(yīng)力差達到最大值。5、通過對多花木蘭和刺槐兩種植物單根系拉拔試驗研究,得到了在相同條件下,多花木蘭根系的拉拔強度要比刺槐根系的拉拔強度大;在相同密度不同含水量條件下,多花木蘭和刺槐根系的最大拉拔力隨含水量的增大呈先增大后減小的趨勢,含水量為21.4%左右時,根系拉拔力達最大值;在相同條件下,多花木蘭和刺槐根系的最大拉拔力隨土樣密度的增大而增大,隨有效根系的增長而增大。以上研究為探索多花木蘭和刺槐兩種灌木根-土復(fù)合體的力學(xué)特性,為這兩種植物應(yīng)用于高速公路邊坡綜合防治具有重要的參考價值。
[Abstract]:High fill and deep excavation is inevitable in the process of highway construction, which not only seriously damages the local ecological environment, but also easily causes geological disasters such as soil erosion, landslides, debris flow and so on, which poses a great threat to the safety of vehicles and human beings. The traditional engineering slope protection technology not only has a large amount of engineering quantity, many consumables, high cost, but also has a single form, and permanently destroys the ecological environment. Therefore, the effective treatment of slope is an urgent problem to be solved in highway engineering construction. Based on the 948 project of State Forestry Administration, "introduction of key techniques for the restoration of deep cutting slope landscape" (project number 101-9968) and the slope entity engineering of the eighth contract section of Dayue Expressway, this paper takes two kinds of shrubs planted as research objects: multiple Hua Mulan and Robinia pseudoacacia. Based on the analysis of plant root distribution characteristics and the shear and pull-out experiments of root-soil complex, the distribution morphology of plant root system and the mechanical properties of root-soil complex were studied. The main innovative achievements of the research are as follows: 1. Through the study of plant root morphological distribution, it is found that there are some differences in root morphology between Robinia pseudoacacia and multiple Hua Mulan shrub, but the main root function of Robinia pseudoacacia is not obvious. The horizontal root system and the oblique root system on the slope are more, intertwined with each other to form a network, which is beneficial to enhance the integrity of the slope soil. The multiple Hua Mulan main root system and the secondary root system are more developed, which play the role of anchor in the slope protection. In order to maintain the stability of slope, it is found that plant roots can effectively improve the shear strength of soil by direct shear tests of multiple Hua Mulan and Root-soil complex of Robinia pseudoacacia. By analyzing and processing the experimental data, it is concluded that the shear strength of root-soil complex conforms to Coulomb's law. According to Coulomb's law, the cohesive force c and internal friction angle 蠁 of multiple Hua Mulan and Robinia pseudoacacia are obtained. The shear strength of multiple Hua Mulan root-soil complex is slightly higher than that of Robinia pseudoacacia root soil complex. Under the same conditions, the shear strength of mixed brucan is the highest, and the shear strength of all oblique cloth root is the second. The shear strength of all vertical roots was the lowest, and the shear strength of root soil complex increased first and then decreased with the increase of root diameter under the same root number and root style, when the root diameter was 1.0mm~1.2mm, the shear strength of root soil complex increased firstly and then decreased with root diameter increasing. The shear strength of root-soil complex reached the maximum value of .4.The stress-strain curves of root soil and root soil complex under different conditions were obtained by triaxial shear test on root soil complex with multiple Hua Mulan and Robinia pseudoacacia. Under different confining pressure and moisture content, when the axial strain is less than or equal to 2, the stress-strain curves of rootless soil and root-soil complex increase linearly, and when the axial strain is greater than 2, the principal stress difference increases slowly. The specimen showed hardening failure, and the final curve tended to be stable, and the principal stress difference reached the maximum value of .5.Through the experimental study on the single root system of two kinds of plants, multiple Hua Mulan and Robinia pseudoacacia, it was obtained that under the same conditions, The pull-out strength of multiple Hua Mulan roots was higher than that of Robinia pseudoacacia roots, and under the same density and different water content, the maximum pull-out strength of multiple Hua Mulan and Robinia pseudoacacia roots increased first and then decreased with the increase of water content. When the water content was about 21.4%, the root pull-out force reached the maximum value, and under the same conditions, the maximum pull-out force of multi-Hua Mulan and Robinia pseudoacacia roots increased with the increase of soil density and with the increase of effective root system. These studies are of great value for exploring the mechanical properties of multiple Hua Mulan and Robinia pseudoacacia shrub root-soil complexes and for the application of these two plants to the comprehensive control of freeway slope.
【學(xué)位授予單位】：中南林業(yè)科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：U416.14

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