刚性抗滑桩的桩土相互作用机理与极限阻滑力研究

Pile-soil interaction mechanism and ultimate lateral load on rigid stabilizing pile

采用新的无量纲参数锚固比作为控制参量,在滑动面从桩顶到桩底逐步变化的过程中,研究不同滑动面位置对土体抗滑桩阻滑工作机理与破坏模式的影响及其演变规律,建议了4种土体抗滑桩阻滑与破坏模式。基于塑性力学极限平衡理论,得到了4种模式的极限阻滑力理论解,给出了它们的界限判别条件。通过试验证明,抗滑桩存在4种阻滑破坏模式,而不是Viggiani假定的3种。建议的桩土相互作用机理模型及其解析解更为合理地描述了任意滑动面位置条件下抗滑桩的阻滑机理与破坏模式。研究表明,滑动面的相对位置决定抗滑桩的工作阻滑模式和极限阻滑力的大小,同一根抗滑桩对沿不同滑动面的滑动所产生的极限阻滑力会有很大的不同。建议的极限阻滑力计算方法可用于常规的滑坡稳定分析计算,对于地下连续墙、嵌岩桩等地下结构亦有重要的借鉴意义,与依靠经验公式与图表计算极限阻滑力的方法相比,所得计算公式在理论上更加完整合理,使用上也更为准确方便。

A new dimensionless parameter, embedding ratio, was proposed. The working and failure mechanisms of the stabilizing pile and their evolutions were studied by gradually changing the location of slip surface from pile top to pile bottom, and four failure modes of stabilizing pile were suggested. Model tests indicate that there are four failure modes of stabilizing pile rather than three modes as proposed by Viggiani. Based on the plasticity theory, analytical solutions of ultimate lateral resistance on rigid stabilizing pile and discrimination boundaries of the four failure modes are obtained, and all of them can be expressed by the new dimensionless embedding ratio. For arbitrary slip surfaces, the failure of the stabilizing pile can be described by the four failure modes. The results show that the failure mode of the stabilizing pile is dominated by the relative location of the slip surface. Consequently, the working mechanism of the same stabilizing pile shall be different provided that the slip surface is different, the corresponding ultimate lateral resistance shall be quite different as well, and the suggested calculation methods of ultimate lateral resistance may be employed for common analysis and design of slope stability.