基于桩身三维效应下的大直径桩纵向振动理论分析和数值模拟

Theoretical analysis and numerical simulation of longitudinal vibration of large-diameter pile based on three-dimensional effect of pile body

考虑桩身三维效应的影响,进行大直径桩的纵向振动研究。首先建立考虑三维波动效应的大直径桩与土体耦合振动模型,得出此模型的耦合振动方程。结合初始条件和边界条件,求解得到桩顶频域响应解析解,并通过卷积定理和傅里叶逆变换得出其时域响应半解析解。接着进行本文模型与Rayleigh-Love杆模型及Euler-Bernoulli杆模型的对比研究,论证本文模型的合理性。通过建立有限元数值计算模型,进行了理论解与数值解的对比分析,两者计算结果较接近,变化规律一致,相互验证了两种模型建立的正确性。最后,分析桩土参数对大直径桩动力响应的影响,得到了各参数对大直径桩振动响应的影响规律,可为大直径桩基础抗震防震设计、完整性检测等提供理论依据。

Considering the influence of the three-dimensional effect of the pile body, the longitudinal vibration study of the large-diameter pile is carried out. Firstly, a coupled vibration model of large-diameter pile and soil considering three-dimensional wave effect is established, and the coupled vibration equation of this model is obtained. Combined with the initial conditions and boundary conditions, the analytical solution of the frequency domain response of the pile top is obtained, and the semi-analytical solution of the time domain response is obtained through the convolution theorem and inverse Fourier transform. Then, the comparison between the model in this paper and the Rayleigh-Love rod model and the Euler-Bernoulli rod model is carried out to demonstrate the rationality of the model in this paper. By establishing a finite element numerical calculation model, a comparative analysis of the theoretical solution and the numerical solution is carried out. Finally, the influence of pile-soil parameters on the dynamic response of large-diameter piles is analyzed, and the influence law of each parameter on the vibration response of large-diameter piles is obtained, which can provide a theoretical basis for seismic design and integrity testing of large-diameter pile foundations.