本文選題：黃土地區(qū) + 公路邊坡�。� 參考：《武漢理工大學》2014年碩士論文

【摘要】：隨著交通基礎設施建設的推進和交通領(lǐng)域的各項深化改革，黃土地區(qū)的高等級公路建設得到了大規(guī)模發(fā)展，同時建設質(zhì)量在不斷的提高，建設水平在不斷的提升。黃土具有特殊的形成過程、成分和性質(zhì)，在降雨條件下無防護邊坡容易沖刷破壞，而過去對邊坡抗沖刷穩(wěn)定性基本上都是從土力學的角度去計算分析，對降雨條件下因雨水降落對坡面的濺擊沖刷及雨水滲流對坡體基質(zhì)吸力的減少，從而導致邊坡穩(wěn)定性降低研究甚少。因此，對黃土地區(qū)公路邊坡植物根系加筋特性進行深入系統(tǒng)地研究顯得十分必要，進一步分析黃土的物理力學性質(zhì)、土質(zhì)特性對邊坡變形機理及變形規(guī)律的影響，不同植物根系對土體變形與強度特性的影響。探索適合黃土地區(qū)的植物配置及植物根系固土數(shù)學模型，為后續(xù)子午嶺林區(qū)公路生態(tài)建設順利推進提供參考，具有重要的研究價值。 本論文以青島至蘭州國家高速公路雷家角（陜甘界）至西峰段生態(tài)邊坡技術(shù)研究實際工程為背景，該公路穿越子午嶺自然保護區(qū)，子午嶺林區(qū)位于黃河中游，是黃土高原面積最大、植被最好的水源涵養(yǎng)林和綠色屏障，也是黃土高原最大的天然次生林區(qū)。邊坡生態(tài)防護是公路生態(tài)環(huán)境建設的重要內(nèi)容，對公路的建設和營運影響較大。本文針對黃土地區(qū)公路邊坡植物根系加筋特性展開的主要研究內(nèi)容如下： 首先，對黃土工程特性、植被根系加筋試驗、植被作用下坡面水力侵蝕、植物根系的固土理論與模型的國內(nèi)外研究現(xiàn)狀進行綜述。在此基礎上，敘述了雷西高速公路的邊坡特點、地形地貌及環(huán)境氣候條件，并利用X-射線衍射儀和電子掃描顯微鏡對子午嶺隧道進口邊坡土體的礦物成分和微觀結(jié)構(gòu)進行了研究。 其次，通過植物根系與土體的相互作用分析了植物根系對邊坡加固穩(wěn)定的機理。并實地選取雷西高速公路子午嶺隧道進口處邊坡植被根系復合原狀土樣，，通過直剪試驗和靜三軸固結(jié)排水試驗研究了無根土、草根、灌木及喬木根系加筋土樣的應力-應變及強度特性，從得到的試驗數(shù)據(jù)探討了在不同植物根系加筋作用下土樣抗剪強度指標的變化規(guī)律。 最后，介紹了公路邊坡的沖刷機理，分析了植被莖葉及根系對邊坡抗沖刷的影響。接著從土體滲流作用力和臨界水力梯度對降雨條件下邊坡穩(wěn)定性破壞的機理進行了詳細分析，概述了黃土這種非飽和土邊坡穩(wěn)定性的有限元分析理論，接著運用GEO-SLOPE2007（SEEP/W、SLOPE/W及SIGMA/W耦合）軟件進行降雨條件下的根-土復合體邊坡穩(wěn)定性分析，將降雨入滲作為土坡穩(wěn)定分析的重要因素，得出在降雨條件下，植物根系的加筋作用對坡體穩(wěn)定性有較大影響。 研究表明：黃土地區(qū)有著特殊的工程地質(zhì)特性，植物根系對加固、保護邊坡體有可支持的力學依據(jù)，植物根系對內(nèi)摩擦角幾乎沒有影響，而對粘聚力有較大提高，能夠有效的穩(wěn)定邊坡。GEO-SLOPE有限元軟件通過滲流、邊坡及應力-應變?nèi)竽K耦合能很好的模擬降雨條件下植物根系對邊坡加筋后的應力-應變及穩(wěn)定性分析。
[Abstract]:With the promotion of the construction of traffic infrastructure and the deepening of the reform in the transportation field, the high grade highway construction in the loess area has been developed in a large scale. At the same time, the quality of the construction is constantly improving and the construction level is constantly improving. The loess has a special formation process, composition and nature, and the unprotected slope is easy to rush under the condition of rainfall. Brush failure, and in the past, the stability of the slope resistance to erosion is basically calculated from the angle of soil mechanics. In the condition of rainfall, the splash erosion and erosion of the slope surface and the decrease of the matrix suction of the slope are reduced, so that the slope stability is reduced very little. Therefore, the reinforcement of the root system of the slope in the loess area is reinforced. It is necessary to make a thorough and systematic study of the characteristics, and further analyze the physical and mechanical properties of the loess, the influence of the soil properties on the deformation mechanism and the deformation law of the slope, the influence of different plant roots to the deformation and strength characteristics of the soil, and explore the suitable mathematical model of the plant distribution and the root soil fixation in the loess region for the follow-up meridian. It is of great research value to provide reference for highway ecological construction in Ridge Forest Region.
This paper is based on the actual project of the ecological slope technology research of the Qingdao to Lanzhou national freeway (Shaanxi Gansu Province) to the Xifeng section. The highway traverses Ziwuling natural reserve and Ziwuling forest area is located in the middle reaches of the Yellow River. It is the largest water source conservation forest and green barrier in the Loess Plateau, and the largest in the Loess Plateau. Natural secondary forest area. Slope ecological protection is an important content of highway ecological environment construction, which has great influence on the construction and operation of highway. The main contents of this paper are as follows: the main research contents of the reinforcement characteristics of the root system of highway slope in the loess area are as follows:
First, the characteristics of the loess engineering, the reinforcement experiment of the vegetation root system, the hydraulic erosion of the slope surface under the action of vegetation, the theory of soil fixation of plant roots and the current research situation at home and abroad are reviewed. On this basis, the slope characteristics, topography and climate conditions of the Lei Xi expressway are described, and the X- ray diffractometer and electronic scanning display are used. The mineral composition and microstructure of the slope at the inlet of Ziwuling tunnel were studied by micromirror.
Secondly, through the interaction between plant root and soil soil, the mechanism of plant root system for slope stabilization is analyzed, and the complex original soil samples of the roots of slope vegetation at the inlet of Ziwuling tunnel of reisi expressway are selected in the field. The root soil, grass roots, shrubs and arbor roots are studied by direct shear test and static three axis consolidation and drainage test. The stress-strain and strength characteristics of samples are investigated. The shear strength indexes of soil samples reinforced by different root systems are discussed based on the obtained experimental data.
Finally, the mechanism of the scour of the highway slope is introduced, and the influence of the stem and leaf and root of the vegetation on the anti scour of the slope is analyzed. Then the mechanism of the slope stability damage under the soil seepage force and the critical hydraulic gradient is analyzed in detail, and the finite element analysis theory of the stability of the unsaturated soil slope is summarized. The GEO-SLOPE2007 (SEEP/W, SLOPE/W and SIGMA/W coupling) software was used to analyze the stability of the soil complex slope under rainfall, and the rainfall infiltration was taken as an important factor for the stability analysis of soil slope, and the effect of the reinforcement effect on the stability of the slope body was greatly influenced by the effect of the reinforcement effect on the plant roots.
The study shows that the loess area has special engineering geological characteristics. The root system has a supporting mechanical basis for strengthening and protecting the slope body. The root system has little influence on the internal friction angle, and the cohesive force is greatly improved. The effective stability of the slope.GEO-SLOPE is through seepage, slope and stress strain three major models. Block coupling can well simulate the stress strain and stability analysis of plant roots reinforced by slope under rainfall.

【學位授予單位】：武漢理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U417.12

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