非均质土中桩端扩散虚土桩法的桩基纵向振动研究

根据桩端土应力扩散的规律，建立了桩端扩散虚土桩模型。基于该模型对非均质土中桩-土纵向耦合振动进行研究。利用复刚度传递多圈层平面应变模型，得到桩与虚土桩桩侧土的剪切复刚度。结合边界条件、初始条件和连续条件，对扩散虚土桩和实体桩动力方程从底层往顶层逐层进行求解，得到桩顶动力响应的频域解析解和时域半解析解。通过对桩端扩散虚土桩扩散角、扩散层厚度、桩侧土非均质性和桩长的影响进行计算分析，得到基于扩散虚土桩法桩-土纵向振动响应特性。研究结论可为桩基础动力设计和动态检测提供理论依据。

Vertical vibration study of pile based on diffused fictitious soil pile model in inhomogeneous soil

Based on rule of stress diffusion, diffused fictitious soil pile model was constructed and the response of soil-pile under axial dynamic loading in inhomogeneous soil was investigated. Firstly, complex stiffness of different soil layers beside pile was gotten by using complex stiffness transfer model of radial multi-zone plane strain. And then combined with boundary condition, initial condition and continuity condition, the dynamical equations of diffused fictitious soil pile and real-body pile were solved from the bottom up. After that the analytical solutions of dynamic response at pile top in frequency domain and the relevant semi-analytical solution of dynamic response in time domain were gained. Finally, the influence analysis of angles of diffused fictitious soil pile, thickness of diffused soil layer, inhomogeneity of lateral soil of pile and length of pile were carried out. Based on diffused fictitious soil pile model, characteristics of the pile-soil coupling interaction in vertical vibration were gotten. The results can provide theoretical basis for dynamic pile design and testing.