基于超静孔压消散的预制静压桩桩侧极限摩阻力计算

Ultimate shaft resistance of jacked piles based on excess pore pressure dissipation

桩侧摩阻力是构成单桩承载力的重要部分,其值主要受到桩周土中有效应力的影响。为了考虑静压桩施工过程对土中有效应力的影响,进而对单桩的极限承载力进行计算。本文针对预制混凝土静压桩的特点,分析桩周土中应力在初始状态、施工过程和再次固结的全过程变化情况,在有效应力法的基础上,利用圆孔扩张理论及固结理论对土中最终有效应力进行计算,得到基于超静孔压消散的桩侧极限摩阻力计算方法。利用文中提出方法完成案例计算,得到了比较合理的结果。

As an important component of the ultimate bearing capacity of the pile,the shaft resistance depends mainly on the effective stress in the soil around the pile.In order to take the stress changing in the soil into account during the single pile ultimate capacity calculation,attention is paid to jacked piles＇ characteristics to analyze the stress changing in pile regime during initial stage,installation and consolidation.The cavity expansion and consolidation theory are applied to the final normal effective stress analysis around the pile,with the ultimate shaft resistance determined by the improved effective stress method developed in this paper.The method is adopted to calculate a practical example with reasonable results obtained.