Vibratory pile driving was investigated through a large-scale experimental model study, whose results were numerically verified by a 3-dimensional finite element analysis (FEA). Drivability of 100-mm-diameter open-ended, closed-ended pipe piles, and 50-mm and 100-mm H piles were studied in a large-scale pressure chamber. The piles were driven into layered and uniform sand deposits under dry and saturated conditions. The effects of saturated or dry sand, pile size, confining pressure, bias weight, unbalanced moment, and redrive on the drivability of piles were investigated parametrically. Tests were performed under confining pressures of 69 and 138 kPa, and the driving frequencies varied from 25 to 35 Hz. A total of 30 tests was performed in homogeneous and layered soils.; The driving was most difficult in a dense layer of blasting sand with a relative density of 90%, but the piles exhibited an increased static bearing capacity in such material. H piles were installed faster than the pipe piles under similar sand and vibrator conditions. The open-ended pipe pile plugged during driving in dry sand but did not plug during continuous driving in the medium-dense saturated sand.; The pore pressure that developed near the pile shaft during driving was significantly higher than that measured in the far-field and was closely related to the rate of penetration, Vp, of the piles. Using a finite element analysis, it was shown that the pore pressure increased (1) with the increase in Vp, and (2) with the decrease in sand permeability below 1.02 mm/sec. The maximum pore pressure was observed beneath the pile toe and sometimes was larger than the effective confining pressure, indicating the possibility of local sand liquefaction.; Static capacity in compression was the highest for the closed-ended pipe pile, followed by the open-ended pipe pile, and the H piles. However, uplift capacity for the open-ended pipe pile was the highest. Finite element analyses indicated that the confining pressure was the most important factor on the static behavior of vibro-driven piles. A static method, considering various soil, pile shape, and installation factors is proposed to predict the static capacity of vibro-driven piles with a good agreement.
展开▼
机译：通过大型实验模型研究了振动桩的打桩，并通过三维有限元分析（FEA）对结果进行了数值验证。在大型压力室中研究了直径为100毫米的开放式，封闭式管桩以及50毫米和100毫米H桩的可驱动性。在干燥和饱和条件下，将桩打入分层且均匀的沙层中。在参数上研究了饱和或干燥的沙子，桩的大小，围压，偏重，不平衡力矩和回弹对桩的驱动性的影响。在69和138 kPa的限制压力下进行测试，驱动频率从25到35 Hz不等。在均质和层状土壤中总共进行了30个测试。在相对密度为90％的致密喷砂层中打桩最为困难，但在此类材料中，桩的静承载力增加。在类似的沙子和振动器条件下，H桩的安装速度比管桩快。开放式管桩在打入干砂时堵塞，但在连续打入中等密度的饱和砂土时没有堵塞。在打桩过程中，在桩身附近产生的孔隙压力显着高于远场中测得的孔隙压力，并且与桩的渗透速率Vp密切相关。使用有限元分析表明，孔隙压力在（1.02 mm / sec）以下随（1）随Vp的增加而增加，（2）随着防砂性的降低而增加。在桩头下方观察到最大孔隙压力，有时甚至大于有效围压，这表明可能发生局部砂土液化。封闭式管桩的压缩静容量最高，其次是开口管桩和H桩。但是，开放式管桩的提升能力最高。有限元分析表明，围压是影响振动桩静力性能的最重要因素。提出了一种考虑各种土壤，桩形和安装因素的静力方法来预测振动桩的静力，并具有良好的一致性。
展开▼
