Abstract A simplified method for predicting the nonlinear dynamic response of composite caisson-piles foundation (CCPF) under scour conditions is proposed. The Hardin-Drnevich model is employed to represent the nonlinear soil reactions. Stress history is also considered to study the scour effect on the dynamic impedance of foundation. Then, harmonic vibration tests considering scour are conducted on a CCPF. It can be observed that the predicted trends of the CCPFs response agree with the experimental data, which verifies the reliability of the method. Then, a case study is investigated to evaluate the effects of stress history, scour depth and soil nonlinearity on the dynamic response of the foundation. The results show that soil nonlinearity has a close relationship with the lateral dynamic displacement of foundation, and it will result in a slight reduction in the resonant dimensionless frequency of the CCPFs. Additionally, with increasing scour depth, a remarkable decrease in the dynamic impedances is produced when soil nonlinearity is considered. Compared with soil nonlinearity, stress history is found to have greater influence on the displacement of the CCPFs, especially in the low frequency range. Finally, a discussion is conducted on the relationships between the resonant frequency of the CCPFs and the scour depth.

中文翻译：

---

冲刷条件下侧向荷载复合沉井桩基础非线性动力特性

摘要 提出了一种预测冲刷条件下复合沉井桩基础(CCPF)非线性动力响应的简化方法。Hardin-Drnevich 模型用于表示非线性土壤反应。还考虑应力历史来研究冲刷对基础动态阻抗的影响。然后，在 CCPF 上进行了考虑冲刷的谐波振动测试。可以观察到，CCPFs响应的预测趋势与实验数据一致，验证了该方法的可靠性。然后，通过案例研究来评估应力历史、冲刷深度和土壤非线性对地基动力响应的影响。结果表明，土体非线性与地基横向动力位移有密切关系，这将导致 CCPF 的谐振无量纲频率略有降低。此外，当考虑土壤非线性时，随着冲刷深度的增加，动态阻抗会显着降低。与土壤非线性相比，应力历史对 CCPF 位移的影响更大，尤其是在低频范围内。最后讨论了CCPF的谐振频率与冲刷深度的关系。尤其是在低频范围内。最后讨论了CCPF的谐振频率与冲刷深度的关系。尤其是在低频范围内。最后讨论了CCPF的谐振频率与冲刷深度的关系。