预应力混凝土管桩挤土效应理论分析

Theoretical analysis on squeezing effect of prestressed concrete pipe pile

分析了国内外预制桩挤土效应的研究现状。在考虑土塞效应的前提条件下,建立了预应力混凝土管桩的柱形孔扩张模型,将预应力混凝土管桩沉桩过程中桩排开的土体体积视为柱形孔扩张时桩侧土体体积变化量与土塞体积之和,利用圆孔扩张理论对预应力混凝土管桩沉入饱和软粘土时的挤土效应进行了研究,得到了桩周土体的应力场、位移场和最终扩张压力的解析解答,为综合研究预应力混凝土管桩的挤土效应和土塞效应提供了一种新的思路。

Firstly, the present study status on squeezing effect of the precast concrete pile is analyzed, then based on the plugging effect, the cylindrical expansion medel of the prestressed concrete pipe pile is established, this model is supposed that the volume of soil squeezed out during the pile driving is equal to the deformation of soil around pile and the volume of soil plug, and the cavity expansion theory is applied to study the squeezing effect of the prestressed concrete pipe pile in saturated soft clay,the analytical solutions to the final expansive pressure, stress field and displacement field of the soil around the pile are presented. The new thought is provided to study the squeezing effect and the plugging effect synthetically.