Experimental Evaluation of Pile-to-Pile Interaction and Impedance Functions with Local Nonlinearity in Soils

本文研究了受强震作用下群桩的阻抗函数。if被定义为动力刚度和动力阻尼，表示上部结构和地基系统界面处的动力特性。一般来说，阻抗函数是在土的线弹性条件下计算的。然而，根据最近的地震事件，强烈的地面运动和由此产生的高振幅结构响应可能会在桩附近的土壤中产生强烈的非线性。因此，本研究在1 g条件下对无黏性土体中嵌固头浮桩进行模型试验，研究土体局部非线性对群桩阻抗特性的影响。这些试验结果表明，土壤非线性显著改变了阻抗特性。

This study dealt with impedance functions (IFs) of pile groups subjected to strong vibrations due to earthquakes. IFs are defined as dynamic stiffness and damping representing dynamic characteristics at the interface between superstructure and soil-foundation systems. In general, impedance functions have been evaluated under linear-elastic conditions of soils. However, in accordance with the recent earthquake events, strong ground motions and resultant high amplitude of structural response may generate strong nonlinearity in soils near the piles. Therefore, this study conducted model tests on fixed-head floating piles embedded in cohesionless soil carried out under 1-g conditions, to investigate the effects of local soil nonlinearity on the impedance characteristics of pile groups. Results obtained from such tests indicate that soil nonlinearity markedly change impedance characteristics.