本文選題：柔性樁 + 接觸界面��； 參考：《湖南工業(yè)大學(xué)》2017年碩士論文

【摘要】：柔性樁屬于典型的摩擦型樁,摩擦型樁承載能力的大小主要取決于樁側(cè)阻力的發(fā)揮,而樁側(cè)阻力的發(fā)揮主要取決于樁土接觸面的工作性狀。本文主要以水泥土樁作為研究對(duì)象,以接觸力學(xué)、摩擦學(xué)及膠凝材料學(xué)等交叉學(xué)科的相關(guān)研究成果為基礎(chǔ),采用直剪試驗(yàn)、掃描電鏡分析、數(shù)值模擬等手段,圍繞樁㧟土界面接觸特性,對(duì)柔性樁㧟土接觸面強(qiáng)度影響因素、樁㧟土接觸面細(xì)觀孔隙率影響因素、柔性樁荷載傳遞影響因素展開(kāi)探討。主要研究工作包括,(1)水泥土樁㧟土接觸面強(qiáng)度的影響因素研究:采用單變量控制法,對(duì)影響樁土接觸面強(qiáng)度的部分因素,如界面粗糙度、水泥摻入比、含水率、養(yǎng)護(hù)齡期,進(jìn)行了分析研究。試驗(yàn)結(jié)果表明:水泥土㧟土的接觸面強(qiáng)度與界面粗糙程度成正相關(guān)關(guān)系,當(dāng)粗糙度不超過(guò)臨界粗糙度時(shí),表現(xiàn)為粗糙度越大,摩擦角越大,而粘聚力隨接觸面粗糙度值的增大先增大后減小;水泥摻入比的改變對(duì)粘聚力的影響較大,且水泥的摻入量并非越大越好,而是存在最佳水泥摻入比(約為0.21);含水率對(duì)摩擦角的影響最為明顯;粘聚力與摩擦角均隨著齡期的增長(zhǎng)而有所增長(zhǎng)。(2)樁土接觸面細(xì)觀孔隙率的影響因素研究:對(duì)掃描電鏡常用的三維孔隙率計(jì)算方法進(jìn)行了分析,對(duì)其計(jì)算方法的利弊與適用范圍進(jìn)行了論證,并提出了改進(jìn)的三維孔隙率計(jì)算模型;基于大量試驗(yàn)數(shù)據(jù),采用MATLAB軟件實(shí)現(xiàn)計(jì)算,試驗(yàn)結(jié)果證明了改進(jìn)計(jì)算模型的合理性;對(duì)水泥土㧟土接觸面進(jìn)行了掃描電鏡試驗(yàn),并通過(guò)對(duì)其孔隙率的計(jì)算,分析了水泥摻入比、含水率等因素對(duì)接觸面孔隙率的影響;從水化反應(yīng)產(chǎn)物的聯(lián)結(jié)狀態(tài)出發(fā),對(duì)接觸面強(qiáng)度的增長(zhǎng)原因進(jìn)行了分析。(3)水泥土樁荷載傳遞的影響因素分析:建立了考慮楔角的荷載傳遞關(guān)系表達(dá)式,建立了數(shù)值計(jì)算模型,分析了樁㧟土相對(duì)剛度、楔形樁的楔角、樁長(zhǎng)等因素,對(duì)柔性樁荷載傳遞規(guī)律的影響,對(duì)比試驗(yàn)結(jié)果表明:樁㧟土相對(duì)剛度對(duì)樁的荷載傳遞的影響是相對(duì)的,主要取決于地基破壞的形式;楔形樁的楔角對(duì)樁側(cè)阻力的發(fā)揮具有決定作用,楔角越大,越有利于樁側(cè)阻力的發(fā)揮;在理想均質(zhì)土層中,樁側(cè)阻力分布形式只與楔角有關(guān),而樁頂荷載大小無(wú)關(guān);所有樁型都存在樁端阻力強(qiáng)化效應(yīng)。
[Abstract]:Flexible pile is a typical friction pile. The bearing capacity of friction pile mainly depends on the exertion of pile side resistance, while the exertion of pile side resistance mainly depends on the working characteristics of pile-soil interface. In this paper, the cement soil pile as the research object, based on the contact mechanics, tribology and cementing materials and other cross-disciplinary research results, using direct shear test, scanning electron microscope analysis, numerical simulation and other means, around the pile? Soil interface contact characteristics for flexible piles? Influence factors of soil contact strength, pile? The influence factors of soil contact surface meso porosity and flexible pile load transfer are discussed. The main research work includes 1) cement soil pile? Study on influencing factors of soil contact strength: single variable control method is used to analyze some factors affecting the strength of pile-soil interface, such as interface roughness, cement blending ratio, moisture content and curing age. The test results show that: cement soil? There is a positive correlation between the contact surface strength and the roughness of interface. When the roughness is less than the critical roughness, the larger the roughness is, the greater the friction angle is, while the cohesion force increases first and then decreases with the increase of the roughness value of the interface. The change of cement blending ratio has a great influence on the cohesion, and the content of cement is not as much as possible, but there is the best cement blending ratio (about 0.21%), the effect of moisture content on friction angle is the most obvious. The factors influencing the meso-porosity of pile-soil contact surface are studied. The three dimensional porosity calculation method commonly used in scanning electron microscope is analyzed. The advantages and disadvantages of the calculation method and the applicable range are demonstrated, and an improved three-dimensional porosity calculation model is put forward, and based on a large number of experimental data, the calculation is realized by using MATLAB software, and the experimental results prove the rationality of the improved calculation model. Cement? The influence of cement ratio, water content and other factors on the porosity of soil contact surface was analyzed by SEM test and the calculation of porosity of soil contact surface, starting from the connection state of hydration reaction products, the influence of cement ratio and water content on the porosity of contact surface was analyzed. The influence factors of load transfer of cement soil pile are analyzed: the expression of load transfer relation considering wedge angle is established, the numerical calculation model is established, and the pile is analyzed. The influence of relative stiffness of soil, wedge angle of wedge pile, length of pile and other factors on the load transfer law of flexible pile shows that: pile? The influence of soil relative stiffness on the load transfer of pile is relative, mainly depends on the failure form of foundation, the wedge angle of wedge pile plays a decisive role on the exertion of pile side resistance, the bigger the wedge angle is, the more favorable it is to the exertion of pile side resistance. In the ideal homogeneous soil layer, the distribution of pile side resistance is only related to the wedge angle, but the pile top load is independent, and all pile types have the effect of pile tip resistance strengthening.
【學(xué)位授予單位】：湖南工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TU473.1

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