不平衡堆载作用下邻近结构桩的侧向受力机制

为了分析结构桩在邻近堆载作用下的受力特性,以条状梯形分布堆载为代表,基于布西奈斯克弹性理论解得出堆载作用下地基附加侧压力表达式,并据此通过对局部塑性变形理论模型的改进,推导得出桩前土体侧移作用下桩身实际附加荷载,同时考虑土体可能发生绕桩流动的极限状态,结合绕桩极限模型给出桩身被动荷载的合理确定方法;在此基础上,考虑地基土体塑性屈服和桩顶结构荷载的影响,基于三参数Winkler弹性地基梁模型,建立桩身自由段、被动受荷段和主动作用段的微分方程,并通过桩身离散与矩阵传递法给出结构桩被动受力特性的半解析解。实测结果、文献理论解与该解答的对比分析,验证了本文计算方法的可靠性。

Lateral mechanical behaviors of structural piles adjacent to imbalanced surcharge loads

In order to analyze the mechanical characteristics of structural piles adjacent to surcharge, the formulation for calculating the lateral additional pressure under strip- trapezoidal surcharge is deduced based on the elastic solution of Boussinesq. Then the actual additional load in front of the structural piles due to lateral soil displacement is obtained by improving the theory of partial plastic deformation. Simultaneously, considering the ultimate state that soil horizontally slides around pile, the rational passive load of structural piles is determined based on the combination of the modified theory of partial plastic deformation with the computational model for the ultimate resistance of the piles surrounded by flow. On this basis, considering the yield of soil and the influence of structural loads on pile head, differential equations for free, passive and active regions of structural piles are established by using the tri-parameter Winkler elastic foundation beam model. By combining the pile discrete method with the matrix transfer method, a semi-analytical solution for passive mechanical behaviors of structural piles is obtained. The calculated results of the proposed solution are compared with the observed results and theoretical solutions in a reference, and its reliability is validated.