Frequency- and intensity-dependent impedance functions of laterally loaded single piles in cohesionless soil
Frequency- and intensity-dependent impedance functions of laterally loaded single piles in cohesionless soil
复制标题
无粘性土中横向荷载单桩的频率和强度相关阻抗函数
DOI：
10.1016/j.sandf.2020.11.004
复制
发表时间：
2021
影响因子：
3.7
通讯作者：
Goit Chandra Shekhar
中科院分区：
文献类型：
--
作者：
Shrestha Naba Raj;Saitoh Masato;Saha Alok Kumer;Goit Chandra Shekhar
本文研究了大振幅荷载下模型土桩基础系统的随频率变化的桩头阻抗特性，从而引起土体屈服。测试是在 1g 条件下对埋入沙中的按比例缩放的单桩进行的。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。通过连接到加载执行器的桩头，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，该加载执行器在除水平方向之外的所有方向上为桩头提供固定。在准静态情况下，施加三种不同速度的荷载来研究桩的横向承载力的速率相关特性。采用 Stereo-PIV 系统测量桩周围的表土位移。侧向承载力随加载速度的变化而变化，但尽管速度发生显着变化，桩附近的土壤仍表现出一致的破坏模式。获得了宽频率范围内从低到高振幅谐波载荷的横向桩头动态阻抗函数。可以看出，随着所有激励频率的动态载荷幅度的增加，动态刚度收敛于正割静态刚度。
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 1gcondition. 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.