本文選題：壓實(shí)黃土 + 增濕��； 參考：《蘭州大學(xué)》2015年碩士論文

【摘要】：隨著西部經(jīng)濟(jì)的快速發(fā)展,壓實(shí)黃土廣泛應(yīng)用地基、路堤等工程中,由于管溝滲水、降雨入滲和地下水位的變化等原因,地基或路堤中壓實(shí)黃土由于增濕,含水量常常會沿寬度和深度方向會發(fā)生一定的變化,造成地基或路堤過大的不均勻沉降,從而危害工程的安全。目前,大部分學(xué)者所研究的黃土濕陷問題,主要是關(guān)于原狀黃土飽和浸水后的濕陷變形和強(qiáng)度問題,而對壓實(shí)黃土增濕到某一含水量的情況研究相對較少,對青海地區(qū)壓實(shí)黃土研究資料更少,基于此,本文以青海黃土為研究對象,采用固結(jié)壓縮試驗(yàn)和直剪試驗(yàn),設(shè)計五種干密度為分別1.4g/cm3、1.5g/cm3、1.6g/cm3、1.7g/cm3、1.8g/cm3,每種干密度分別設(shè)計10%、13%、15%、18%、20%的五種增濕含水量的壓實(shí)黃土進(jìn)行研究,獲得了含水量w和干密度ρd對試樣強(qiáng)度和變形特性的影響,結(jié)果表明：壓實(shí)黃土含水量w一定,干密度ρd增大,試樣的壓縮模量Es增大；干密度ρd一定時,含水量w增加,試樣的壓縮模量Es呈指數(shù)函數(shù)Es=aebw形式減小。壓實(shí)黃土干密度ρd相同,當(dāng)含水量w增加,試樣的粘聚力c呈指數(shù)函數(shù)c=aebw的形式減小,而內(nèi)摩擦角φ呈一次函數(shù)φ=aw+b的形式而減�。粔簩�(shí)黃土含水量w相同,當(dāng)干密度島增大時,試樣的內(nèi)摩擦角φ一直少量增加,而粘聚力c增大較快且幅度逐漸變大,可以用指數(shù)函數(shù)c=aebρd來表示變化規(guī)律。根據(jù)固結(jié)試驗(yàn)和直剪試驗(yàn)獲得變形參數(shù)和強(qiáng)度參數(shù),采用FLAC3D軟件模擬管溝小量滲水,引起黃土地基的增濕變形,結(jié)果表明：對不同干密度的壓實(shí)黃土地基,在滲水導(dǎo)致的增濕范圍內(nèi),沉降值變化幅度較大,超增濕范圍后,沉降值變化的幅度較小；當(dāng)干密度小于1.60g/cm3時,提高干密度,可以顯著消弱黃土地基由于滲水增濕產(chǎn)生的沉降值和沉降差,當(dāng)干密度大于等于1.60g/cm3,提高干密度,消弱效果不明顯。
[Abstract]:With the rapid development of western economy, compacted loess is widely used in foundation, embankment and other engineering, because of the seepage of pipe ditch, rainfall infiltration and the change of groundwater level, the compacted loess in foundation or embankment is due to humidification. The water content will often change along the width and depth of the embankment, resulting in uneven settlement of the foundation or embankment, thus endangering the safety of the project. At present, the problem of loess collapsibility studied by most scholars is mainly about the collapsing deformation and strength after saturated soaking of undisturbed loess, but the research on the situation of compacted loess humidifying to a certain water content is relatively few. The research data of compacted loess in Qinghai area are less. Based on this, the consolidation compression test and direct shear test are adopted in this paper, taking Qinghai loess as the research object. Five dry densities of 1.4 g / cm ~ 3 / 1.5 g / cm ~ 3 ~ 1.6 g / cm ~ (3) ~ 1.7 g / cm ~ (3) and 1.8 g / cm ~ (3) were designed respectively. The effects of water content w and dry density 蟻 _ d on the strength and deformation properties of specimens were obtained. The results show that when the moisture content of compacted loess is constant, the dry density 蟻 _ d increases, the compression modulus es increases, and when the dry density 蟻 _ d increases, the compression modulus es decreases in the form of exponential function Esaebw. The dry density 蟻 d of compacted loess is the same. When the water content w increases, the cohesive force c decreases in the form of exponential function c=aebw, while the internal friction angle 蠁 decreases in the form of primary function 蠁 aw b, and the moisture content of compacted loess is the same. When the dry density island increases, the internal friction angle 蠁 increases slightly, while the cohesive force c increases rapidly and the amplitude increases gradually, which can be expressed by the exponential function c=aeb 蟻 d. According to consolidation test and direct shear test, deformation parameters and strength parameters are obtained. FLAC3D software is used to simulate the small amount of water seepage in pipe trenches, which results in humidification deformation of loess foundation. The results show that: for different dry density compacted loess foundation, In the range of humidification caused by water infiltration, the variation of sedimentation value is larger than that of superhumidification range, and when dry density is less than 1.60g/cm3, the dry density is increased. The settlement value and settlement difference of loess foundation caused by water infiltration and humidification can be significantly reduced. When the dry density is greater than or equal to 1.60 g / cm ~ (3), the dry density can be increased, but the effect of weakening is not obvious.
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P642.131

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