本文關(guān)鍵詞： 群樁效應(yīng) FLAC~(3D) 樁頂沉降 靜載試驗(yàn) 相對(duì)位移　出處：《遼寧工程技術(shù)大學(xué)》2013年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著中國(guó)經(jīng)濟(jì)的迅猛發(fā)展,城市對(duì)群樁的需求逐年增長(zhǎng)。為了讓樁和樁間土的承載性能充分發(fā)揮,有必要對(duì)影響群樁效應(yīng)的因素深入研究。以遼寧省氣象局東北區(qū)域氣象中心業(yè)務(wù)樓的單樁靜載試驗(yàn)為基礎(chǔ),運(yùn)用FLAC3D有限差分軟件進(jìn)行單樁和群樁的數(shù)值模擬,分析豎向荷載作用下群樁效應(yīng)的影響因素對(duì)沉降、樁側(cè)阻力、樁端阻力等方面的變化規(guī)律,并這些結(jié)論能夠給今后類似地質(zhì)條件下的群樁設(shè)計(jì)提供一些參考。 首先,根據(jù)工程的實(shí)際背景模擬單樁靜載試驗(yàn),結(jié)果比較模擬數(shù)據(jù)和實(shí)測(cè)數(shù)據(jù)樁頂沉降誤差為0.03mm,是實(shí)測(cè)值的6.3%。而且通過樁、土體的沉降計(jì)算接觸面相對(duì)位移。粘性土極限位移為6～12mm,施加到最后一級(jí)荷載時(shí),樁土體的相對(duì)位移未達(dá)到此值,因此,樁側(cè)阻力荷載分擔(dān)曲線呈上升趨勢(shì)。其次,對(duì)同一壓強(qiáng)和相同地質(zhì)條件下的單樁和群樁地基數(shù)值模擬比較研究,得出群樁基樁的樁頂沉降值遠(yuǎn)遠(yuǎn)大于單樁樁頂沉降值,且同一承臺(tái)下的各單樁樁頂沉降中,中樁沉降最大,其次是邊樁沉降,角樁沉降最小。最后,通過改變樁長(zhǎng)、樁距、承臺(tái)寬度等參數(shù)對(duì)群樁地基的受力性狀和變形特性進(jìn)行了數(shù)值模擬。結(jié)果表明：相同豎向荷載作用下,樁長(zhǎng)越大,沉降越�。粯毒嘣酱�,沉降越��；承臺(tái)寬度與樁長(zhǎng)比例越大,沉降越小。相同荷載作用下不同樁距的群樁樁身軸力變化相似,都是上部軸力變化小,中下部變化較大。樁的軸力沿樁身長(zhǎng)度方向先增大,然后逐漸減小,而且樁的軸力最大值是樁身頂面下來的某個(gè)深度處,并不是在樁頂面。群樁中各樁樁側(cè)阻力是自上而下逐漸發(fā)展,且各樁樁身中下部的側(cè)阻大,上部側(cè)阻則明顯小于下部側(cè)阻,同時(shí)樁下部側(cè)阻值隨著樁距的增大而增大。隨著上部荷載的增大,群樁基礎(chǔ)中樁分擔(dān)荷載的百分比非線性增長(zhǎng)。
[Abstract]:With the rapid development of Chinese economy, the demand for pile groups in cities is increasing year by year. In order to give full play to the bearing capacity of piles and soil between piles, Based on the static load test of single pile in northeast regional meteorological center building of Liaoning Meteorological Bureau, the numerical simulation of single pile and pile group is carried out by using FLAC3D finite difference software. This paper analyzes the influence factors of pile group effect on settlement, pile side resistance and pile tip resistance under vertical load, and these conclusions can provide some references for pile group design under similar geological conditions in the future. First of all, according to the actual background of the project, the static load test of single pile is simulated. The results show that the settlement error of the pile top is 0.03mm compared with the measured data, which is 6.3mm of the measured value. The ultimate displacement of clay soil is 6 ~ 12 mm. When applied to the last stage load, the relative displacement of pile soil is not up to this value. Therefore, the load sharing curve of pile side resistance shows an upward trend. The numerical simulation and comparison of single pile and group pile foundation under the same pressure and same geological conditions show that the settlement value of pile top of group pile foundation is much larger than that of single pile top, and the settlement of middle pile is the largest in each single pile top settlement under the same pile cap. Secondly, the settlement of side pile is the smallest, and the settlement of angle pile is the smallest. Finally, by changing the length of pile, the distance of pile and the width of pile cap, numerical simulation is carried out on the mechanical behavior and deformation characteristic of pile group foundation. The results show that: under the same vertical load, The larger the pile length, the smaller the settlement; the larger the pile spacing, the smaller the settlement; the greater the width of the cap and the length of the pile, the smaller the settlement. The axial force of the pile first increases along the length of the pile body and then decreases gradually, and the maximum axial force of the pile is a certain depth down the top of the pile body. It is not on the top of the pile. The side resistance of each pile in the pile group develops gradually from top to bottom, and the side resistance in the middle and lower part of the pile body is large, and the side resistance in the upper pile is obviously smaller than that in the lower pile. At the same time, the lateral resistance increases with the increase of pile spacing, and the percentage of pile sharing load increases nonlinearly with the increase of upper load.
【學(xué)位授予單位】：遼寧工程技術(shù)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：TU473.1

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