【摘要】：溝谷地形區(qū)域的地質(zhì)、水文情況較為復(fù)雜，受限于道路建設(shè)成本及道路路線要求，致使部分橋梁樁基修建在斜坡上。溝谷地形的形成及發(fā)展主要是由溝谷流水侵蝕和坡面物質(zhì)移動造成，因此該地區(qū)樁基又不可避免的遭到水流沖刷的影響。 本文闡述了斜坡及水流沖刷后樁基豎向承載機理，建立了斜坡和水流沖刷后樁基的整體受力模型，首次提出了考慮邊坡系數(shù)與臨坡距耦合條件下的斜坡樁基側(cè)摩阻力影響系數(shù)的計算公式，以及考慮沖刷深度的沖刷后側(cè)壓力引起摩阻力影響系數(shù)的計算公式，形成了溝谷地形樁基豎向承載力評價方法，對該地區(qū)橋梁樁基的設(shè)計、養(yǎng)護、評估具有重大意義。 在分析斜坡對樁基豎向極限承載力的影響時，結(jié)合斜坡樁基豎向承載機理，通過有限差分軟件FLAC3D進行建模計算，分析其對豎向極限承載力、樁端極限阻力、樁側(cè)極限摩阻力的影響。通過數(shù)值計算結(jié)果可知，邊坡系數(shù)、臨坡距對樁基豎向極限承載力的影響主要集中在對樁側(cè)極限摩阻力的影響；二者與樁側(cè)極限摩阻力呈正相關(guān)，且二者存在耦合相關(guān)，當(dāng)二者減小時對樁側(cè)極限摩阻力敏感性增強。 在分析沖刷對樁基豎向極限承載力的影響時，通過有限差分軟件FLAC3D中的NULL單元模擬樁周土的沖刷過程，分析其對極限承載能力、樁端極限阻力、樁側(cè)極限摩阻力以及樁周土的側(cè)壓力的影響。通過數(shù)值計算結(jié)果可知，沖刷深度對樁基豎向極限承載力的影響主要集中在對樁側(cè)土壓力引起摩阻力的影響；按照高承臺模式計算沖刷后樁基豎向極限承載力是不準(zhǔn)確的。 在綜合考慮斜坡、沖刷對豎向極限承載力影響以及樁基承載機理的基礎(chǔ)上，提出斜坡樁基側(cè)摩阻力影響系數(shù)和沖刷后側(cè)壓力引起摩阻力的影響系數(shù)，并通過對前面計算結(jié)果的回歸分析給出兩種系數(shù)的計算公式，最終總結(jié)得出了溝谷地形樁基豎向極限承載力計算公式。
[Abstract]:The geological and hydrological conditions in the valley terrain area are more complicated, which are limited by the cost of road construction and the requirements of road route, resulting in the construction of some bridge piles on the slope. The formation and development of the valley topography are mainly caused by the erosion of the gully and the material movement on the slope, so the pile foundation in this area is inevitably affected by the flow of water. In this paper, the vertical bearing mechanism of slope and pile foundation after water flow erosion is expounded, and the integral force model of pile foundation after slope and water flow erosion is established. For the first time, a formula for calculating the influence coefficient of the side friction of the slope pile foundation considering the coupling of slope coefficient and the distance between the slope and the slope is put forward, and the formula for calculating the influence coefficient of the friction caused by the lateral pressure after taking into account the erosion depth is also presented. The evaluation method of vertical bearing capacity of pile foundation in gully terrain is formed, which is of great significance to the design, maintenance and evaluation of bridge pile foundation in this area. When analyzing the influence of slope on the vertical ultimate bearing capacity of pile foundation, combined with the vertical bearing mechanism of slope pile foundation, the finite difference software FLAC3D is used to model and calculate the vertical ultimate bearing capacity and ultimate resistance of pile end. The influence of the ultimate friction resistance on the pile side. The results of numerical calculation show that the influence of slope coefficient and adjoining distance on the vertical ultimate bearing capacity of pile foundation is mainly concentrated in the influence of the ultimate frictional resistance on the pile side, and they are positively correlated with the ultimate frictional resistance of the pile side, and there is a coupling correlation between them. The sensitivity to the ultimate frictional resistance of the pile side is enhanced when both of them are reduced. When analyzing the influence of scour on the vertical ultimate bearing capacity of pile foundation, the scouring process of soil around pile is simulated by NULL element in finite difference software FLAC3D, and the ultimate bearing capacity and ultimate resistance of pile end are analyzed. The influence of the ultimate frictional resistance of the pile and the lateral pressure of the soil around the pile. The numerical results show that the effect of scour depth on the vertical ultimate bearing capacity of pile foundation is mainly concentrated on the influence of the soil pressure on the pile side, and it is not accurate to calculate the vertical ultimate bearing capacity of the pile foundation after scouring according to the high cap model. On the basis of considering the influence of slope, erosion on the ultimate vertical bearing capacity and the bearing mechanism of pile foundation, the influence coefficient of lateral friction of slope pile foundation and the coefficient of friction caused by lateral pressure after erosion are put forward. The formulas for calculating the vertical ultimate bearing capacity of pile foundation in gully terrain are given by regression analysis of the results of the previous calculation.
【學(xué)位授予單位】：長安大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U443.15

【參考文獻】

相關(guān)期刊論文 前10條

1 俞宗衛(wèi),張建英;黃土地基中靜壓樁單樁豎向承載力的試驗分析[J];四川建筑科學(xué)研究;2002年01期

2 蘇沛東;大直徑嵌巖樁的高應(yīng)變動力測試技術(shù)應(yīng)用研究[J];中外公路;2005年03期

3 程劉勇;陳善雄;余飛;許錫昌;李劍;秦尚林;;豎向荷載下斜坡樁基承載力及影響因素數(shù)值研究[J];科學(xué)技術(shù)與工程;2013年18期

4 王楠;徐永臣;宋玉鵬;朱龍海;胡日軍;;沖刷作用下樁基承載能力分析[J];海洋地質(zhì)前沿;2013年09期

5 陳鵬;李文華;范濤;龐吉蓮;;土體沖刷對橋梁樁基影響的三維差分模擬計算分析[J];山東科技大學(xué)學(xué)報(自然科學(xué)版);2007年04期

6 邱鈺,周琳,劉松玉;深長大直徑嵌巖樁單樁承載性狀的有限元分析[J];土木工程學(xué)報;2003年10期

7 吳興序;莊衛(wèi)林;吉隨旺;熊國斌;;昔格達軟巖中灌注樁單樁豎向承載力試驗研究[J];西南交通大學(xué)學(xué)報;2006年06期

8 胡春林,李向東,吳朝暉;后壓漿鉆孔灌注樁單樁豎向承載力特性研究[J];巖石力學(xué)與工程學(xué)報;2001年04期

9 趙明華;劉建華;楊明輝;;傾斜荷載下高陡邊坡橋梁基樁內(nèi)力計算[J];巖石力學(xué)與工程學(xué)報;2006年11期

10 趙春風(fēng),蔣東海,崔海勇;單樁極限承載力的靜力觸探估算法研究[J];巖土力學(xué);2003年S2期

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