斜桩基础受力特性研究

Study of force characteristics of battered pile foundation

斜桩在群桩中起到承受较大水平荷载的作用,被广泛应用于桥梁、码头以及大型输电线路等建构筑物的基础中。群桩基础中,斜桩对竖向和水平荷载的分担作用不仅是力的分解问题,还与群桩中斜桩与直桩的单桩轴向和侧向刚度有关,进行斜桩群桩基础分析需要考虑轴向与侧向刚度的耦合。通过对直桩、斜桩的单桩侧向和轴向承载特性的分析以及群桩基础荷载分担情况的分析,揭示了斜桩基础的受力性状。负斜桩单桩侧向刚度最大,直桩次之,正斜桩最小。桩长对单桩轴向刚度的影响非常明显,桩长越长,轴向刚度越大,轴向刚度与侧向刚度之间的差异也就更加显著。群桩基础大部分竖向荷载由桩轴向力承担;当轴向刚度与侧向刚度的比值较小,基础水平荷载主要由桩侧向力承担;当轴向刚度与侧向刚度的比值很大,基础水平荷载主要由桩轴向力承担;当桩的倾斜角较小时,由基础水平荷载引起的桩轴向力较大。

Due to the carrying capacity of horizontal load, battered piles were generally used in the foundations of bridge, wharf and transmission power line. The horizontal and vertical load sharing of piles is not only force decomposition, which is related with the axial and lateral stiffness of inclined and vertical piles. The influence of axial and lateral stiffnesses coupling should be considered in the analysis of inclined group piles foundation. According to the studies of the axial and lateral stiffness of inclined and vertical piles and the analysis of load sharing of group piles, the force characteristics of battered pile foundation were gained. First, the lateral stiffness of positive inclined pile is biggest; and the lateral stiffness of vertical pile is bigger than that of negative inclined pile. Second, the influence of pile length on the axial stiffness is very significant. When the pile was lengthened, the axial stiffness was increased; and the differences between axial stiffness and lateral stiffness were expanded. Last, most of the vertical load was borne by the axial force of piles. When the ratio of axial stiffness and lateral stiffness is small, most of the horizontal load was borne by the lateral force of piles. When the ratio of axial stiffness and lateral stiffness is large, most of the horizontal load was borne by the axial force of piles. At the same time, due to the inclined angle of pile is small, the large axial force is created to resist horizontal load.