基于振动台试验的扩孔微型桩受力和变形性能研究

Research on Mechanical and Deformation Properties of Micro-pile with Predrilled Oversize Hole Based on Shaking Table Test

为了研究扩孔微型桩在地震作用下的受力和变形性能,在有无扩孔、不同扩孔深度、不同扩孔孔径、不同扩孔材料4种参数下对微型桩进行了振动台试验研究,计算得到了扩孔微型桩桩身弯矩和侧向位移,并分析得到了不同扩孔参数下微型桩的桩身弯矩与侧向峰值位移对应的埋深位置及桩身弯矩与位移的分布规律。结果表明:扩孔微型桩桩身峰值位移最大值出现在土体表面位置,并随桩深不断减小,扩孔后微型桩桩身峰值弯矩和峰值位移增大;随着扩孔深度的增加,桩身峰值位移和桩身峰值弯矩也增大,并且桩身峰值弯矩最大值点有向下移动的趋势;所得结论可为地震作用下扩孔微型桩受力和变形性能研究奠定基础,同时为新型半整体式桥台桥梁中扩孔微型桩的设计和应用提供参考。

In order to study the mechanical and deformation properties of micro-pile with predrilled oversize hole under earthquake, the micro-piles with 4 kinds of parameters including with or without predrilled oversize hole, different diameters, different depths of predrilled oversize, different materials of predrilled oversize were conducted by shaking table test. The bending moment and lateral displacement of micro-pile were obtained by computation. The corresponding depth positions and the distribution laws of bending moment and peak lateral displacement under different parameters of micro-pile were obtained by analyzing. The results show that the maximum peak displacement of micro-pile with predrilled oversize hole is found at surface of soil, and is decreased along the depth of pile, the peak bending moment and peak displacement of micro-pile will increase after predrilling oversize hole. With the increase of depth of pile with predrilled oversize hole, the peak displacement and peak bending moment of pile are increased, and the maximum peak moment point has the trend of moving downward. The conclusions from above analyzing can offer a foundation for the research on the mechanical and deformation properties under earthquake, and provide references for the designing and application of micro-pile with predrilled oversize hole in new semi-integral abutment jointless bridges.