冲刷作用下单桩循环加载特性的模型试验

通过模型试验对高铁桥梁单桩基础进行静载试验和循环加载试验,探讨了不同冲刷深度下单桩循环累积沉降和动位移幅值的发展规律.研究结果表明:桩基循环累积沉降随冲刷深度增加而增加,对于冲刷深度较小的桩,循环累积沉降和沉降平均速率在较少的循环次数内即可趋于稳定;而对于冲刷深度较大的桩,循环累积沉降大且发展较快,达到稳定需要的时间长,甚至持续发展以致破坏,在实际工程中应重视长期循环累积沉降对其承载特性的影响.

Influence of Scour Depth on Vertically Cyclic Behaviors of Single Pile with Model Tests

A series of model tests on static and cyclic axial response of the single pile in sandy soils are described. The accumulated settlement and cyclic amplitude of settlement of piles are investigated for different scour depths. The results indicate that the increase of scour depth can induce the increase of accumulated settlement of piles under cyclic loading. For smaller scour depths, the accumulated settlement and average rate of settlement tend to stable at less cycles. However, for larger scour depths, the accumulated settlement is large and develops very fast and needs longer time to reach stable, which even causes the sustainable development of accumulated settlement to lead to failure of piles. The effect of long term accumulated settlement on bearing capacity should be considered in engineering practices.