本文選題：紡錘型樁　切入點(diǎn)：有限元數(shù)值模擬　出處：《浙江海洋學(xué)院》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：我國沿海地區(qū)分布有大量新沉積細(xì)顆粒土,多為淤泥質(zhì)軟土,其力學(xué)性質(zhì)為孔隙比大,含水量高,常表現(xiàn)出欠固結(jié)性。這類沉積土用于農(nóng)業(yè)設(shè)施基礎(chǔ)時(shí),由于地基軟弱,常采用樁基礎(chǔ)。欠固結(jié)土固結(jié)過程中會(huì)引起地基土沉降,產(chǎn)生樁側(cè)負(fù)摩阻力,對樁產(chǎn)生下拽力,可能會(huì)造成樁身破壞、樁端地基的破壞等;地基一旦沉降幅度較大,就會(huì)使承臺(tái)底部與地基土相互脫離,產(chǎn)生承臺(tái)脫空現(xiàn)象;地基沉降可能也會(huì)對臨近的建筑物產(chǎn)生影響,使臨近建筑物產(chǎn)生傾斜或者裂縫,造成嚴(yán)重的工程事故。因此,我們需要對軟土中樁身負(fù)摩擦力問題及地面沉降問題進(jìn)行研究。本文提出了一種新的樁型-紡錘型樁,研究其樁側(cè)負(fù)摩阻力特性和控制地面沉降的技術(shù)應(yīng)用。首先根據(jù)樁的形狀和受力情況,對紡錘型樁負(fù)摩阻力特性進(jìn)行理論分析。其次,運(yùn)用ABAQUS軟件分別建立紡錘型樁與等截面單樁的三維有限元數(shù)值分析模型,通過數(shù)值模擬分析影響樁側(cè)負(fù)摩阻力的幾個(gè)主要因素,如摩擦系數(shù)、土的內(nèi)摩擦角、粘聚力、樁頂載荷、地面堆載和土體固結(jié)時(shí)間等。對比紡錘型樁較等截面樁的優(yōu)勢,研究結(jié)果證明,紡錘型樁錐角的存在有利于減少樁負(fù)摩阻力,提高樁基承載力,減少地面沉降。最后,文章介紹了紡錘型樁的構(gòu)造設(shè)計(jì)、工作原理以及樁土相互作用機(jī)理,表明其在控制地面沉降、防治承臺(tái)脫空的優(yōu)越性,從而指出紡錘型樁值得推廣應(yīng)用。新型紡錘型樁的研究將是一項(xiàng)具有創(chuàng)新性的研究工作,該樁型具有承載力高、型式簡單、施工方便,恰當(dāng)?shù)剡\(yùn)用該工藝可以節(jié)省材料,提高承載力,能有效地減少負(fù)摩阻力對基樁的影響,對于欠固結(jié)地基中農(nóng)業(yè)設(shè)施的建造與使用具有重要的理論價(jià)值和工程意義;掌握地面沉降控制技術(shù),能更好的減少工程隱患,保證人們的生命財(cái)產(chǎn)安全;因此,該研究具備較高的學(xué)術(shù)價(jià)值和工程應(yīng)用價(jià)值。
[Abstract]:China's coastal area distribution of a large number of new deposits of fine soil, mostly silt soft soil, the mechanical properties for large void ratio, high water content, often exhibit less consolidation. This kind of sedimentary soil for agricultural infrastructure, because the foundation is weak, often uses the pile foundation under consolidated soil consolidation will be. Due to the sedimentation of foundation soil in the process of producing, pile side friction of pile, downdrag, may cause damage of pile, pile foundation settlement failure; once greatly, will make the bottom of cap and soil from each other, which may cap the void phenomenon; foundation settlement will also close the buildings affect nearby buildings tilted or cracks, causing serious engineering accident. Therefore, we need to carry out research on soft soil pile friction and the ground settlement problems. This paper presents a new type of pile - spindle type pile. Application of the pile side friction resistance and negative characteristics of ground subsidence control. According to the pile shape and stress, theoretical analysis of the spindle type of negative friction resistance of pile characteristics. Secondly, establish spindle type pile and single pile with uniform cross section of the three-dimensional finite element model using ABAQUS software, through the analysis of numerical simulation several main factors of negative friction resistance of pile side effects, such as friction coefficient, internal friction angle of soil, cohesion, load of pile top, ground loading and consolidation time. Compared with the uniform pile pile spindle advantages, research results show that the cone angle of the spindle type pile is conducive to reduce the negative friction of piles resistance, improve the bearing capacity of pile and reduce the surface subsidence. Finally, this paper introduces the structural design of spindle type pile, the working principle and the pile-soil interaction mechanism, demonstrate the superiority of prevention and control of ground settlement, pile cap removal from empty. And pointed out that the spindle type pile is worthy of popularization and application. Research on a new type of spindle type pile is an innovative research work, this type of pile has high bearing capacity, simple type, convenient construction, proper use of this technology can save materials, improve the bearing capacity, can effectively reduce the effect of negative friction on pile foundation that has important theoretical value and engineering significance to the construction and use of under consolidated soil agricultural facilities; control technology of ground subsidence, can better reduce the project risk, ensure the safety of people's life and property; therefore, the research has high academic value and engineering application value.

【學(xué)位授予單位】：浙江海洋學(xué)院
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU473.1;TU433

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