分层土中群桩水平动力阻抗的改进计算

采用动力Winkler地基梁模型，建立了主动桩和被动桩的简化解析运动方程，考虑地基土的分层特性、桩身剪切变形和转动惯量，提出了计算分层地基中单桩和群桩动力阻抗的改进计算方法，并与已有文献的计算结果进行了对比，结果表明：改进方法的计算结果与现场实测更接近。在低频段，改进方法的计算结果与已有文献结果较一致，但随着桩身剪切模量的减小，两者差异增大。差异主要是由考虑桩身剪切变形和转动惯量引起的，且前者影响较大，在低频段差异亦十分明显，而后者影响较小，在群桩阻抗峰值区域和高频段差异明显，需考虑桩身转动惯量的影响。

Improved calculation for lateral dynamic impedance of pile groups in layered soil

Based on a dynamic Winkler model, a simplified calculation method of both active and passive piles in the case of multi-layered soils is presented. An advanced method is deduced to compute the lateral dynamic impedance of both single pile and pile groups in multi-layered soils, which takes pile shaft shear deformation and moment of inertia into account. Compared with the already results of experiment and computations, the presented results are more close to the tests. The text result is consistent with a correlative thesis in low frequency, but both difference increases when pile shaft shear modulus decreases. Pile shaft shear modulus and moment of inertia are the reasons to cause the differences. The former plays a greater effect even in low frequency. The latter has a little effect, but an evidence differences appear during the pile impedance in peak value and the frequency is high. Thus pile shaft moment of inertia should be taken into account in high frequency.