The effect of the gap near the surface in the earthquake response of the structure-pile foundation-ground system

结构-桩基-地面体系在地震作用下的动力特性，已忽略了桩头附近的间隙。因此，本研究基于弹塑性理论，建立了考虑“地表与桩顶间隙”的路基反力模型。该模型还考虑了循环荷载的影响。离心模型试验验证了响应分析的数值结果。对一种临时塔机在桩基上支承进行了数值和实验分析。两种分析结果一致。桩顶间隙的产生和扩大对塔机振动特性的影响也很明显。这意味着考虑间隙的路基反力模型对结构-桩基础-地面体系的地震反应分析具有较好的精度。

The gap near the pile head has been passed over in dynamic behavior of the structure-pile foundation-surface ground system during an earthquake. Therefore, in this study, the subgrade reaction model considering "the gap between surface ground and pile head" was formulated on the elasto-plasticity theory. And that the effect of cyclic loading was also considered in this model. The numerical results of the response analysis were verified by the centrifugal model experiment.A temporary tower crane that was supported on the pile foundation was numerically and experimentally analyzed. Both analytical results agreed well. And also, it became clear that the generation and expansion of the gap near the pile head effected on the vibration characteristics of the tower crane.It is meant that the subgrade reaction model considering the gap is useful to analyze the earthquake response of structure-pile foundation-surface ground system at the good accuracy.