高加筋土擋墻的試驗及數(shù)值分析研究
發(fā)布時間：2018-09-13 10:42
【摘要】：土工合成材料作為一種加筋材料被廣泛應用在基礎(chǔ)、邊坡、道路等工程中，對邊坡災害的防治具有特殊效果，但加筋機制和設(shè)計理論方面的研究卻落后于工程實際，從而影響加筋技術(shù)的發(fā)展。本文以神農(nóng)架機場I邊坡高加筋土擋墻為主要研究對象，通過室內(nèi)拉拔試驗，對土工格柵與碎石土的界面特性進行了深入研究，并通過Plaxis建立神農(nóng)架機場I邊坡高加筋土擋墻數(shù)值模型，，對不同施工階段的擋墻進行數(shù)值分析，取得如下主要成果： 1）對高密度聚乙烯格柵HDPE130、HDPE170兩種土工格柵與碎石土的界面特性進行拉拔試驗，分析了不同上覆荷載下及不同拉拔位移時筋材的變形與剛體平動過程，研究了界面摩阻力漸進發(fā)揮及非均勻性變化過程，以及在不同上覆荷載情況下，筋帶的似摩擦系數(shù)的變化規(guī)律，和殘余摩擦系數(shù)在高上覆荷載下的主導作用。 2）假設(shè)土體為理想的Mohr-Coulomb彈塑性模型，通過Plaxis巖土有限元分析軟件建模擬不同階段擋墻的應力-應變情況，運用強度折減法模擬分析擋墻的潛在滑動面位置和安全系數(shù)，研究土工格柵加筋土擋墻三種破壞模式，并發(fā)現(xiàn)加筋土內(nèi)部滑動面一般始于各級擋墻的坡腳，而加筋土外部，擋墻被視為一個整體，滑動面符合朗肯土壓力理論。 3）高加筋土擋墻中未加筋土部分及加筋土部分不同斷面的水平位移分布及擋墻在垂直面上最大位移的分布位置規(guī)律，發(fā)現(xiàn)加筋抑制土體的應變，導致筋材末端與未加筋土接觸的位置，因土體的應變差異而產(chǎn)生剪應力集中。 4）數(shù)值計算模型基于傳統(tǒng)的Mohr-Coulomb準則，所得數(shù)值計算結(jié)果普遍大于實際觀測數(shù)據(jù)，說明Mohr-Coulomb準則并不能完全準確的反應筋-土的特征，因此使用Mohr-Coulomb準則計算加筋土時有一定的局限性。
[Abstract]:As a reinforced material, geosynthetics have been widely used in foundation, slope, road and other projects, which have special effects on slope disaster prevention, but the research on reinforcement mechanism and design theory lags behind the engineering practice. This affects the development of reinforcement technology. Taking the high reinforced earth retaining wall of Shennongjia Airport I slope as the main research object, the interfacial characteristics of the geogrid and the gravel soil are studied deeply through the indoor pull-out test. The numerical model of high reinforced earth retaining wall of Shennongjia Airport I slope is established by Plaxis, and the numerical analysis of retaining wall in different construction stage is carried out. The main results are as follows: 1) the interface characteristics of the two geogrid and gravel soil in HDPE grille HDPE130,HDPE170 are tested by pull-out test. The deformation and rigid body translational processes of steel bars under different overburden loads and different drawing displacements are analyzed, and the progressive exertion of interfacial friction resistance and the variation process of inhomogeneity are studied, as well as under different overburden loads. The variation law of the similar friction coefficient of the steel strip and the dominant effect of the residual friction coefficient on the high overburden load. 2) assuming that the soil is an ideal Mohr-Coulomb elastoplastic model, The stress-strain situation of retaining wall at different stages is simulated by Plaxis software, and the potential sliding surface position and safety factor of retaining wall are simulated by strength reduction method, and three failure modes of geogrid reinforced earth retaining wall are studied. It is also found that the internal sliding surface of reinforced earth usually begins at the slope foot of the retaining wall at all levels, and outside the reinforced earth, the retaining wall is regarded as a whole. The sliding surface accords with Rankine earth pressure theory. 3) horizontal displacement distribution of different sections of unreinforced soil and reinforced earth in high reinforced earth retaining wall and the distribution of maximum displacement of retaining wall on vertical plane. It is found that reinforcement inhibits the strain of soil and results in the position of contact between the end of reinforcement and unreinforced soil. 4) the numerical model is based on the traditional Mohr-Coulomb criterion. The numerical results obtained are generally larger than the observed data, which indicates that the Mohr-Coulomb criterion can not completely reflect the characteristics of the reinforced soil. Therefore, the use of the Mohr-Coulomb criterion in the calculation of reinforced soil has some limitations.
【學位授予單位】：長江科學院
【學位級別】：碩士
【學位授予年份】：2013
【分類號】：TU476.4
本文編號：2240948
[Abstract]:As a reinforced material, geosynthetics have been widely used in foundation, slope, road and other projects, which have special effects on slope disaster prevention, but the research on reinforcement mechanism and design theory lags behind the engineering practice. This affects the development of reinforcement technology. Taking the high reinforced earth retaining wall of Shennongjia Airport I slope as the main research object, the interfacial characteristics of the geogrid and the gravel soil are studied deeply through the indoor pull-out test. The numerical model of high reinforced earth retaining wall of Shennongjia Airport I slope is established by Plaxis, and the numerical analysis of retaining wall in different construction stage is carried out. The main results are as follows: 1) the interface characteristics of the two geogrid and gravel soil in HDPE grille HDPE130,HDPE170 are tested by pull-out test. The deformation and rigid body translational processes of steel bars under different overburden loads and different drawing displacements are analyzed, and the progressive exertion of interfacial friction resistance and the variation process of inhomogeneity are studied, as well as under different overburden loads. The variation law of the similar friction coefficient of the steel strip and the dominant effect of the residual friction coefficient on the high overburden load. 2) assuming that the soil is an ideal Mohr-Coulomb elastoplastic model, The stress-strain situation of retaining wall at different stages is simulated by Plaxis software, and the potential sliding surface position and safety factor of retaining wall are simulated by strength reduction method, and three failure modes of geogrid reinforced earth retaining wall are studied. It is also found that the internal sliding surface of reinforced earth usually begins at the slope foot of the retaining wall at all levels, and outside the reinforced earth, the retaining wall is regarded as a whole. The sliding surface accords with Rankine earth pressure theory. 3) horizontal displacement distribution of different sections of unreinforced soil and reinforced earth in high reinforced earth retaining wall and the distribution of maximum displacement of retaining wall on vertical plane. It is found that reinforcement inhibits the strain of soil and results in the position of contact between the end of reinforcement and unreinforced soil. 4) the numerical model is based on the traditional Mohr-Coulomb criterion. The numerical results obtained are generally larger than the observed data, which indicates that the Mohr-Coulomb criterion can not completely reflect the characteristics of the reinforced soil. Therefore, the use of the Mohr-Coulomb criterion in the calculation of reinforced soil has some limitations.
【學位授予單位】：長江科學院
【學位級別】：碩士
【學位授予年份】：2013
【分類號】：TU476.4
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