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由于基桩纵向截面形式的差异,竖向荷载作用下桩侧摩阻力和桩端阻力发挥存在明显的差异,尽管纵向截面异形桩在工程中得到了一定的应用,然而针对极限荷载下桩端和桩侧土体破坏形式的研究却相对较少。基于透明土材料和粒子图像测速(particle image velocimetry)技术,针对等体积的扩底楔形桩、楔形桩和等截面桩的承载特性及破坏形式进行对比模型试验,测得桩顶荷载-沉降曲线,研究了各级荷载下桩端和桩侧土体位移场的变化规律以及极限荷载下桩端和桩侧土体的破坏形式;同时分析了不同桩长情况下各类型桩的承载力特性。研究结果表明,在此试验条件下,扩底楔形桩的极限承载力约为常规楔形桩的3.5倍和等截面桩的2.5倍;极限荷载作用下各类型纵向截面异形桩桩端的破坏形式规律基本一致。
Due to the difference in the longitudinal section of foundation piles, there are obvious differences between pile friction resistance and pile tip resistance under vertical loads. Although the longitudinal section profiled piles have been applied in engineering, the end of the piles are subjected to ultimate loads. There are relatively few researches on the failure modes of the soil around the pile. Based on the transparent soil material and particle image velocimetry technology, a comparative model test was conducted on the load bearing characteristics and failure modes of equal-sized enlarged base wedge-shaped piles, wedge-shaped piles and equal-section piles, and the load-settlement curve at the pile top was measured. The variation of displacement field at the pile end and the pile side soil under different loads and the failure modes of the soil at the pile end and the pile side under the limit load are studied. The bearing capacity characteristics of various piles under different pile lengths are analyzed. The results show that under the experimental conditions, the ultimate bearing capacity of the expanded wedge-shaped pile is about 3.5 times that of the conventional wedge-shaped pile and 2.5 times that of the equal-section pile; Consistent.