斜桩周围的土体自重应力场不对称于斜桩轴线,其承载变形特性比较复杂。在砂土地基中开展了斜桩模型试验,研究了斜桩在垂直于其倾斜方向的水平偏心荷载作用下的承载变形特性,分析了桩身表面粗糙程度、桩身倾角对斜桩承载变形特性及桩身内力分布规律的影响。试验结果表明,在垂直于斜桩倾斜方向的水平偏心荷载作用下,斜桩桩顶水平位移很小,而扭转变形较大,其承载力取决于扭转变形。垂直于斜桩倾斜方向的水平偏心荷载不仅会使斜桩弯曲,还会使斜桩沿其纵向轴线拉伸。斜桩桩身最大弯矩超过作用于桩顶的扭矩约10%~30%,斜桩全长受拉,但桩身轴力很小,最大轴力约为桩顶水平荷载的5%。斜桩桩身表面作用有纵向摩阻力及环向摩阻力。斜桩桩身上部纵向摩阻力为正摩阻力,下部则为负摩阻力,中性点的位置约在相对深度Z/L=0.3处,纵向平均摩阻力远小于相同深度处的环向平均摩阻力。
Abstract
The bearing deformations of battered piles are intricate due to the asymmetrical stress field exerted by the self-weight of the surrounding soil. Model tests were conducted on battered piles embedded in sandy soils to investigate their bearing deformation behavior under horizontal eccentric loads perpendicular to their inclination direction. The study also revealed the effects of pile surface roughness and pile shaft inclination angle on the bearing deformation characteristics of battered piles, as well as the internal forces acting on the pile shaft. Test results manifest that under horizontal eccentric loads perpendicular to the inclined direction of battered piles, the horizontal displacement of the pile head is minimal, while torsional deformation is significant. The bearing capacity of battered piles primarily relies on their torsional bearing capacity. When a horizontally applied eccentric load is perpendicular to the pile’s inclination, the battered pile not only undergoes bending but also experiences tension along its longitudinal axis. The maximum bending moment induced in the battered pile shaft by the horizontal load exceeds the torque moment applied at the pile top by approximately 10% to 30%. The entire battered pile shaft is subjected to tension, although the tension is relatively small, with a maximum tensile force equal to around 5% of the horizontal load applied at the pile head. The pile shaft is also subjected to longitudinal and circumferential skin frictions. The upper shaft exhibits positive longitudinal skin friction, while the lower shaft exhibits negative friction, with the neutral point located at a depth of Z/L=0.3. The average longitudinal skin friction is considerably smaller than the average circumferential skin friction at the same depth.
关键词
斜桩 /
模型试验 /
扭转承载力 /
水平偏心荷载 /
纵向摩阻力 /
环向摩阻力
Key words
battered pile /
model test /
torsional capacity /
horizontal eccentric loads /
longitudinal skin friction /
circumferential skin friction
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基金
陕西省自然科学基础研究计划项目(2019JM-006)
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