考虑复杂地基反力分布的嵌岩灌注桩屈曲稳定分析

Buckling Analysis of Rock-Socketed Filling Pile under Complicated Subgrade Modulus

嵌岩灌注桩因其诸多优点在桥梁等工程领域中广泛使用,但当上覆土层软弱且桩顶自由长度较大时,桩身屈曲稳定问题应引起重视。为探讨桩侧土约束对桩身屈曲稳定的影响,假定地基反力系数呈更一般的幂分布,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解答,并据此讨论了地基反力系数分布模式、桩身自重及桩侧摩阻力等对桩身屈曲稳定的影响规律。这些定性的规律对嵌岩灌注桩的设计与施工具有一定的指导意义。

Rock-socketed filling piles have been widely used especially in bridge engineering due to its advantages. But when the covering subsoil is weak or the unsupported pile top part is long, the buckling failure of the pile shaft should be regarded as a problem. To investigate the influence of the constraint of surrounding soil, on the buckling of the pile shaft, the most general exponential 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, solutions for the buckling length and the load of the pile shaft are deduced by applying the minimum potential energy principle. And based on the obtained solutions, influencing rules of the distribution of subgrade reaction coefficient, deadweight and side resistance on the buckling behavior of the pile shaft are discussed respectively in detail. These rules may be applied to guide the design and construction of the rock-socketed filling pile.