考虑径向非匀质性的层状地基中单桩动力阻抗研究

Research on vertical dynamic impedance of single-pile considering radially inhomogeneous layered soil

采用考虑桩周土的非匀质性的Novak薄层法计算桩土相互作用的方法,对考虑径向非匀质性的层状地基土中端承桩竖向动力阻抗的简化计算方法进行研究,得到相应的计算公式。分析桩周土非匀质性、泊松比、振动频率等因素对单桩竖向动力阻抗的影响。分析结果表明,考虑径向非匀质层状地基土的阻抗实部随频率的提高而增大,但增大的幅度不大,阻抗虚部也随频率提高而增大,且增大的幅度较大;非匀质区与匀质区土的剪切模量比对桩的竖向动力阻抗实部基本无影响;单桩竖向动力阻抗随非匀质土区域范围减小而增大;单桩竖向动力阻抗实部随土的泊松比增大而减小。

On the basis of the research on simple analytical computation of vertical dynamic impedance of single-pile, Novak layer method which applies computing the dynamic impedance to vertical vibration for radially inhomogeneous soil was introduced to analyze vertical dynamic pile-soil interaction. The simple analytical computation on the vertical dynamic impedance of single-pile in layered soil was studied, with considerations of radial inhomogeneity of soil. The formula for computing vertical dynamic impedance of single-pile was obtained. Based on the computing formula, the result is found that the dynamic impedance of single-pile considering radially inhomogeneous layered soil will increase when the frequency improves. The extent of the real part of impedance is small, but that of the imaginary part shows an opposite trend. And shear modulus ratio of inhomogeneous soil and homogeneous soil have little effect on the real part of vertical dynamic impedance of single-pile; The vertical dynamic impedance of single-pile has an upward trend when the size of inhomogeneous zone decrease, however if Poisson＇s ratio increase sharply, the real part of the vertical dynamic impedance of single-pile will reduce.