Abstract This paper investigates the frequency-dependent pile-head impedance characteristics of a model soil-pile foundation system under large amplitude loads, inducing soil yielding. Testing was conducted on a scaled single pile embedded in sand under a 1g condition. A laminar shear box mounted on a unidirectional shaking table was used to house the soil-pile foundation system. Quasi-static loads and dynamic loads were applied to obtain the force–displacement relationships and pile-head impedance functions, respectively, through the pile head connected to a loading actuator providing fixity to the pile head in all directions, except horizontal. In the quasi-static case, loads with three different velocities were applied to study the rate-dependent characteristics of the lateral bearing capacity of the pile. The Stereo-PIV system was employed to measure the surface soil displacement around the pile. The lateral bearing capacity changed with the loading velocity, but the soil near the pile showed a consistent failure pattern despite a significant change in velocity. Lateral pile-head dynamic impedance functions were obtained for low-to-high amplitude harmonic loading for a wide range of frequencies. The dynamic stiffness was seen to converge to that of the secant static stiffness with an increase in the amplitude of the dynamic loading for all the excitation frequencies.

中文翻译：

---

无粘性土中横向加载单桩的频率和强度相关阻抗函数

摘要 本文研究了模型土桩基础系统在引起土体屈服的大振幅载荷下的频率相关桩头阻抗特性。测试是在 1g 条件下对嵌入沙子的成比例单桩进行的。安装在单向振动台上的层流剪切箱用于容纳土桩基础系统。通过连接到加载致动器的桩头，施加准静态载荷和动态载荷，分别获得力-位移关系和桩头阻抗函数，在除水平方向外的所有方向上固定桩头。在准静态情况下，施加三种不同速度的载荷来研究桩侧承载力的速率相关特性。Stereo-PIV 系统用于测量桩周围的表层土壤位移。横向承载力随加载速度而变化，但尽管速度发生了显着变化，但桩附近的土壤显示出一致的破坏模式。横向桩头动态阻抗函数是针对大范围频率的低到高振幅谐波加载获得的。对于所有激励频率，随着动态载荷振幅的增加，动态刚度会收敛到割线静态刚度。横向桩头动态阻抗函数是针对大范围频率的低到高振幅谐波加载获得的。对于所有激励频率，随着动态载荷振幅的增加，动态刚度会收敛到割线静态刚度。横向桩头动态阻抗函数是针对大范围频率的低到高振幅谐波加载获得的。对于所有激励频率，随着动态载荷振幅的增加，动态刚度会收敛到割线静态刚度。