斜坡基桩的斜坡空间效应及其水平承载特性研究

Study on spatial effect of slope and horizontal bearing behavior of piles in sloping ground

为研究水平荷载作用下斜坡基桩的斜坡空间效应对其承载特性的影响,设计并完成了不同坡度及水平荷载作用角度下斜坡基桩室内模型试验,测得了桩顶荷载位移曲线及桩身弯矩分布。结果分析表明:水平荷载相同时,桩顶水平位移及桩身最大弯矩均随坡度增加呈非线性增大,随水平荷载作用角度增加而呈线性减小;基桩水平极限承载力却随坡度增加而减小,随水平荷载作用角度增加而增大。坡度每增加30°,桩顶水平位移约增大1.3~1.9倍,桩身最大弯矩增大约17%~30%;水平荷载作用角度每增加30°,桩顶水平变形减小约25%~30%,桩身最大弯矩减小约6%~11%。斜坡基桩的桩身最大弯矩位于地面以下3~6倍桩径范围内,坡度越大桩身最大弯矩位置越深。分析得到了基桩水平极限承载力拟合公式,可以为斜坡基桩设计提供参考。

To study the influence of spatial effect of slope and horizontal bearing behavior of piles in sloping ground, a series of model tests were designed and carried out considering various horizontal loading angles and slope angles, and then the loading-displacement curve of pile top and the bending moment distribution along pile shaft were obtained. The analysis results indicate that： for the same horizontal loading, both the horizontal displacement at pile top and the maximum bending moment along pile shaft increase nonlinearly with the increase of slope angle, while they decrease linearly with the increase of the horizontal loading angle. The horizontal ultimate bearing capacity decreases with the increase of slope angle, and increases with the increase of horizontal loading angle. For every increase of 30° for slope angle, the horizontal displacement at pile top increases by 1.3 to 1.9 times, and the maximum bending moment along pile shaft increases by 17% to 30%. For every increase of 30° for the horizontal loading angle, however, the horizontal displacement at pile top can be reduced approximately by 25% to 30% and the maximum bending moment along pile shaft can be reduced by 6% to 11%. The maximum bending moment along pile shaft in sloping ground is within the range of 3 to 6 pile diameters below the ground surface, and the larger the slope angle is, the deeper the maximum bending moment occurs. The fitting formula of the horizontal ultimate bearing capacity was attained, reference for the design of piles in sloping ground. provides