植物根系對紅粘土邊坡的加固效應研究
發(fā)布時間：2019-07-01 15:07
【摘要】：用傳統(tǒng)的剛性防護措施對紅粘土邊坡加固存在諸多問題,如結(jié)構物易損壞、破壞周邊生態(tài)環(huán)境、陽光照射后眩光等,使用邊坡生態(tài)防護這種新型防護方法可以有效避免這些問題,它不但能夠增強邊坡的穩(wěn)定性,防止滑坡、泥石流等災害發(fā)生,減少水土流失,還能保護、恢復邊坡周邊的生態(tài)環(huán)境,改善局部微氣候。本文基于植物根系的加筋理論和錨固理論,結(jié)合植物根系形態(tài)及分布特點,借助室內(nèi)直剪試驗和有限元數(shù)值仿真模擬對植物根系加固紅粘土邊坡的加筋和錨固效應展開分析研究,分析探討了紅粘土在不同含水率情況下抗剪強度隨含根量變化的規(guī)律,對影響木本植物根系錨固作用的因素進行有限元分析并通過正交試驗分析探討了單根長度、單根距坡底水平距離、單根與水平向夾角這幾個關鍵因素對邊坡穩(wěn)定性的影響,得出以下主要研究結(jié)論:(1)通過一系列土力學試驗研究了紅粘土的基本物理特性,通過快剪試驗分析研究了安徽皖南地區(qū)紅粘土在不同含水率下的抗剪強度。制備根—土復合體剪切試樣,采用室內(nèi)直剪試驗研究分析了含水率、含根量變化對根—土復合體抗剪強度的影響規(guī)律。(2)采用MATLAB軟件對根—土復合體直剪試驗數(shù)據(jù)進行曲面擬合,得出了粘聚力增加值隨含水率、含根量變化的二元二次擬合方程。(3)有限元分析結(jié)果顯示邊坡穩(wěn)定性排列順序為:木本植物根系作用邊坡草本植物根系作用邊坡原始邊坡。從邊坡穩(wěn)定系數(shù)上看木本植物的固坡效果要強于草本植物,且草本植物在限制邊坡水平位移方面要弱于木本植物。(4)通過分析不同工況下的有限元模型,發(fā)現(xiàn)主直根型木本植物的根系發(fā)揮錨固作用時,主直根起到主要作用,側(cè)根系起到輔助作用;發(fā)現(xiàn)將根系布置在邊坡底部時固坡效果最好,布置在邊坡上部時效果最差,且根系布置水平間距不宜小于2.5m;發(fā)現(xiàn)在坡高小于等于15m且坡度緩于1:0.75的邊坡上采用具有主直根型根系的木本植物進行防護效果較好。(5)正交試驗結(jié)果顯示,影響邊坡穩(wěn)定性的因素主次排列順序為:單根距坡底水平距離㧐單根長度㧐單根與水平向夾角。試驗得出了單根錨固的較優(yōu)取值水平,即單根長度為4m,單根距坡底水平距離為0m,單根與水平向夾角為45°。
[Abstract]:There are many problems in strengthening red clay slope with traditional rigid protection measures, such as easy damage of structure, damage of surrounding ecological environment, glare after sunlight irradiation, etc. These problems can be effectively avoided by using slope ecological protection, which can not only enhance the stability of slope, prevent landslide, debris flow and other disasters, reduce soil and water loss, but also protect and restore the ecological environment around the slope. Improve the local microclimate. In this paper, based on the reinforcement theory and anchoring theory of plant roots, combined with the morphology and distribution characteristics of plant roots, the reinforcement and anchoring effects of red clay slope strengthened by plant roots were analyzed and studied by means of laboratory direct shear test and finite element numerical simulation, and the variation of shear strength with root content under different water content was analyzed and discussed. The factors affecting root anchoring of woody plants were analyzed by finite element method, and the effects of single root length, horizontal distance from single root to the bottom of slope, angle between single root and horizontal direction on slope stability were discussed by orthogonal test. The main conclusions are as follows: (1) the basic physical properties of red clay were studied by a series of soil mechanics tests. The shear strength of red clay in southern Anhui Province under different moisture content was studied by fast shear test. The shear samples of root-soil complex were prepared. The effects of moisture content and root content on the shear strength of root-soil complex were studied and analyzed by laboratory direct shear test. (2) the surface fitting of root-soil complex direct shear test data was carried out by MATLAB software, and the increasing value of cohesion with water content was obtained. The binary quadratic fitting equation of root content change. (3) the results of finite element analysis show that the order of slope stability is as follows: woody plant root acting on slope herbaceous root acting on slope original slope. From the point of view of slope stability coefficient, the slope fixation effect of woody plants is stronger than that of herbaceous plants, and the horizontal displacement of woody plants is weaker than that of woody plants. (4) by analyzing the finite element model under different working conditions, it is found that the main straight roots play a major role and the lateral roots play an auxiliary role when the roots of the main straight roots play an anchoring role. It is found that the effect of fixing slope is the best when the root is arranged at the bottom of the slope, and the effect is the worst when the root is arranged in the upper part of the slope, and the horizontal spacing of the root arrangement should not be less than 2.5m. It is found that the protective effect of woody plants with main and straight root roots is better on the slope with slope height less than or equal to 15 m and the slope is slower than 1 鈮，
本文編號：2508588
[Abstract]:There are many problems in strengthening red clay slope with traditional rigid protection measures, such as easy damage of structure, damage of surrounding ecological environment, glare after sunlight irradiation, etc. These problems can be effectively avoided by using slope ecological protection, which can not only enhance the stability of slope, prevent landslide, debris flow and other disasters, reduce soil and water loss, but also protect and restore the ecological environment around the slope. Improve the local microclimate. In this paper, based on the reinforcement theory and anchoring theory of plant roots, combined with the morphology and distribution characteristics of plant roots, the reinforcement and anchoring effects of red clay slope strengthened by plant roots were analyzed and studied by means of laboratory direct shear test and finite element numerical simulation, and the variation of shear strength with root content under different water content was analyzed and discussed. The factors affecting root anchoring of woody plants were analyzed by finite element method, and the effects of single root length, horizontal distance from single root to the bottom of slope, angle between single root and horizontal direction on slope stability were discussed by orthogonal test. The main conclusions are as follows: (1) the basic physical properties of red clay were studied by a series of soil mechanics tests. The shear strength of red clay in southern Anhui Province under different moisture content was studied by fast shear test. The shear samples of root-soil complex were prepared. The effects of moisture content and root content on the shear strength of root-soil complex were studied and analyzed by laboratory direct shear test. (2) the surface fitting of root-soil complex direct shear test data was carried out by MATLAB software, and the increasing value of cohesion with water content was obtained. The binary quadratic fitting equation of root content change. (3) the results of finite element analysis show that the order of slope stability is as follows: woody plant root acting on slope herbaceous root acting on slope original slope. From the point of view of slope stability coefficient, the slope fixation effect of woody plants is stronger than that of herbaceous plants, and the horizontal displacement of woody plants is weaker than that of woody plants. (4) by analyzing the finite element model under different working conditions, it is found that the main straight roots play a major role and the lateral roots play an auxiliary role when the roots of the main straight roots play an anchoring role. It is found that the effect of fixing slope is the best when the root is arranged at the bottom of the slope, and the effect is the worst when the root is arranged in the upper part of the slope, and the horizontal spacing of the root arrangement should not be less than 2.5m. It is found that the protective effect of woody plants with main and straight root roots is better on the slope with slope height less than or equal to 15 m and the slope is slower than 1 鈮，
本文編號：2508588
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