發(fā)布時(shí)間：2018-09-11 11:31

【摘要】：黃土地區(qū)的非均勻濕陷性對(duì)橋梁樁基等一系列工程具有重要的影響。因此，如何確定非均勻濕陷黃土區(qū)樁基承載力和樁側(cè)負(fù)摩阻力大小是橋梁樁基設(shè)計(jì)中亟待解決的關(guān)鍵問(wèn)題。本文依托山西河運(yùn)高速大厚度黃土地區(qū)非均勻濕陷條件下的橋梁樁基項(xiàng)目，利用土工離心模型試驗(yàn)和數(shù)值模擬，對(duì)非均勻濕陷黃土地區(qū)群樁基礎(chǔ)承載特性和復(fù)雜地形條件下黃土地基橋梁群樁承載特性進(jìn)行了系統(tǒng)的研究。 在離心模型試驗(yàn)中，采用土中加荷載的方法模擬浸水所產(chǎn)生黃土的不均勻濕陷。主要進(jìn)行了黃土在非均勻濕陷條件下的單樁、群樁系列的模型試驗(yàn)，研究了樁頂沉降、樁身軸力、樁側(cè)摩阻力等一系列承載特性，探討了黃土的均勻和非均勻濕陷變形對(duì)樁基負(fù)摩阻力的影響，同時(shí)分析了不同樁數(shù)和不同樁間距對(duì)群樁效應(yīng)的影響，進(jìn)一步分析了不同地形條件對(duì)群樁的樁負(fù)摩阻力影響。 最后，運(yùn)用有限元MIDAS軟件，基于黃土濕陷的機(jī)理，提出了用“力水等效”原理模擬黃土非均勻濕陷變形，，并且依托山西河運(yùn)高速橋梁樁基項(xiàng)目，對(duì)群樁的受力特性進(jìn)行數(shù)值模擬，分析了群樁在豎向荷載作用下群樁樁側(cè)摩阻力的變化規(guī)律。
[Abstract]:The non-uniform collapsibility in loess area has an important influence on a series of projects such as bridge pile foundation. Therefore, how to determine the bearing capacity of pile foundation and the negative frictional resistance of pile side in non-uniform collapsible loess area is the key problem to be solved urgently in the design of bridge pile foundation. In this paper, based on the bridge pile foundation project in the loess region of high speed and large thickness of Shanxi River, the geotechnical centrifuge model test and numerical simulation are used. The bearing characteristics of pile group foundation in non-uniform collapsible loess area and the bearing characteristics of loess foundation bridge under complex terrain are studied systematically. In the centrifuge model test, the inhomogeneous collapsibility of loess caused by soaking is simulated by adding load in soil. The model tests of single pile and pile group series under the condition of non-uniform collapsibility of loess are carried out, and a series of bearing characteristics, such as pile top settlement, pile axial force, pile side friction and so on, are studied. The influence of uniform and non-uniform collapsing deformation of loess on the negative friction of pile foundation is discussed. At the same time, the influence of different pile number and different pile spacing on pile group effect is analyzed, and the influence of different topographic conditions on pile negative friction is further analyzed. Finally, based on the mechanism of loess collapsibility, the finite element MIDAS software is used to simulate the inhomogeneous collapsing deformation of loess, and to rely on the pile foundation project of Shanxi River high speed bridge. Numerical simulation is carried out on the mechanical characteristics of pile groups, and the variation law of lateral friction of group piles under vertical load is analyzed.
【學(xué)位授予單位】：長(zhǎng)安大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U443.15

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