高承台嵌岩灌注桩屈曲稳定分析的能量法统一解及工程应用

A Unified Analytic Solution to the Buckling Problem of Rock-Socketed Filling Pile with Highrise Cap by Energy Method

为探讨桥梁工程中高承台嵌岩灌注桩的屈曲稳定特性,假定桩侧地基反力系数呈非线性的幂分布,基于弹性地基梁理论建立桩土体系总势能方程,采用最小势能原理导得桩身屈曲临界荷载与计算长度统一法解答,并据此讨论了地基反力分布、桩身自重、桩侧摩阻力及桩顶自由长度等对桩身屈曲稳定的影响规律。工程应用结果表明,考虑地基反力的复杂分布时,桩身屈曲分析结果更趋合理。

To investigate the buckling behavior of rock-socketed filling piles widely used in bridge engineering, the nonlinear power function distribution of subgrade reaction coefficient is assumed and the total potential energy equation of the pile-soil system is set up based on the simplified elastic beam model. Then, a unified analytic solution for the buckling length and load of pile shaft is deduced by applying the minimum potential energy principle. And based on the obtained solution, influencing rules by the distribution of subgrade reaction coefficient, deadweight, side resistance and the pile top＇s unsupported length on the buckling behavior of pile shaft are discussed respectively in detail. These rules may be applied to guide the design and construction of rock-socketed filling pile. Application in an engineering example shows that, if practically complicated distributions of lateral subgrade reaction are considered, more reasonable buckling analysis results of rock-socketed filling piles with highrise cap will be obtained.