受土体侧移作用既有轴向受荷单桩的简化算法

A Simplified Analysis Method for an Axially Loaded Single Pile Subjected to Lateral Soil Movement

摘要:

基于弹性桩的挠曲微分方程,结合Winkler地基模型和Poulos两阶段法,提出了一种近似考虑土体侧移和既有轴向荷载耦合作用的单桩简化算法,采用有限差分方法进行求解,求解过程简便并可应用于分层地基中.通过与典型算例的对比,验证了该方法的合理性.参数分析表明,在土体侧移与轴向荷载耦合作用下,由于P-Δ效应,将在桩身内产生一定的附加位移和弯矩,根据桩身材料性质、土体弹性模量和桩顶约束条件等的不同,其影响程度有所不同,其中桩顶约束条件对桩的位移和弯矩分布特性具有显著影响,而桩顶约束的存在可以明显降低土体侧移与既有轴力耦合作用所带来的不利影响.研究结论对于实际工程具有借鉴意义.

Abstract:

Based on the flexural differential equation of elastic piles,a simplified analytical solution of an axially loaded single pile subjected to lateral soil movement is put forward.In this solution,the subsoil is simulated with the Winkler’s spring model and a twostage method proposed by Poulos is introduced to establish the equations.The flexural differential equation is solved by the finite difference method,which is more convenient and more adaptable for layered foundations.The method is validated by some typical examples calculated by other methods.Results show that the interactive effects between soil movement and the axial load have some influence on the behavior of piles by generating additional displacements and bending moments which may be quite different according to the properties of both piles and soil as well as boundary conditions of pile head.The boundary conditions of pile head have obvious influence on the distribution of displacement and stress of pile.An effective restrain at the head of pile can reduce the negative couple effects of axial load and lateral soil movement acting on the pile.The present method can be applied to practical engineering.