尹平保+赵明华+赵衡+贺炜

长沙理工大学 桥梁结构安全控制湖南省工程实验室，湖南 长沙410114）摘要：考虑坡面以下一定深度范围内地基抗力非线性分布模式，建立了基桩稳定性分析简化计算模型及桩坡体系总势能方程.据此导得了斜坡段桩柱式桥梁基桩临界荷载与计算长度的能量法解答，并通过平地和斜坡两种不同情况下的室内模型试验验证理论计算方法的合理性.由此进行的参数分析表明：增大墩柱弹性模量或减小墩柱高度（高长比）均可提高基桩稳定性，当高长比取0.3～0.4时，基桩稳定性最佳；当边坡坡度在25°～35°范围内时，基桩稳定性受斜坡效应的影响较小，设计时应尽量将基桩设置在坡度小于35°的边坡上.斜坡段地基抗力比例系数m与坡度α之间的相互影响关系尚有待深入研究.

关键词：桥梁工程；基桩；稳定性；能量法；斜坡效应

中图分类号：TU473 文献标识码：AStability Analysis of Pilecolumn Bridge

of Bridge Structure （Changsha University of Science & Technology），Changsha，Hunan410114，China）Abstract：The soil resistance is a nonlinear function varying with depth， and it is related to the effect of location in slopes. The simplified model for a pilecolumn bridge pile and the total potential energy equation of pileslope system were presented by considering the slope effect. The analytical solution of the critical load and calculated length were derived based on the energy method. In this respect， verification between the measurement and theoretical solution was conducted by dissimilar conditions in plain and slope. The parametric study shows： the increase of the Young's modulus of the pier column or decrease of its free length enhances the stability of the pile foundation； the appointed elastic modulus of pier column corresponds to an optimal columnheight， and the best stability is achieved while the ratio is in the range of 0.3 to 0.4. Moreover， a key conclusion from observations is that the bridge pile should be located at the slope with the gradient less than 35° for safety. However， the correlation between m and α is of significance so that it needs to be further investigated.

Key words：bridge engineering；piles foundation；stability；energy method；slope effect

在西部山区修建桥梁工程，多采用桩柱式桥梁基桩，且往往将其设置在斜坡甚至悬崖峭壁上.与普通的桥梁基桩相比，位于斜坡上的桩柱式桥梁基桩具有坡度陡、墩柱高（普遍在30 m以上）等特点.因此，无论是受力分析还是稳定性计算，目前尚缺乏统一完善的技术标准或规定，给工程设计与施工带来极大不便，从而导致斜坡段桥梁基桩稳定性问题日益突出[1-3].

有关基桩稳定性问题，自20世纪60年代以来，国内外已有许多学者对其展开了一些有益研究，如：美国学者Lee（1968），利用钢管和铝管模拟基桩，进行了相应的室内模型试验研究[4]；……