Centrifuge Analysis of Coupled Soil-pile-structure Interaction

Abstract

乾燥砂地盤中の単杭の地震時挙動について調べるため, 遠心模型実験を行う。模型短杭は先端支持杭であり, 1または2自由度の上部工を杭頭に取り付 ける。動的挙動を調べるため, 40ｇの遠心場で, 一定の振幅約1.5m/s2, 1Hzから12Hzの振動数で正弦波加振する。実験結果に基づい て, 慣性の相互作用と幾何的相互作用, および自由度の違いが全体系の応答に与える影響について考察したところ, 入力加速度の振動数が相互作用に与 える影響について興味深い結果が得られたので報告する。

A series of systematic centrifuge tests is conducted in order to study the seismic response of end bearing single piles embedded in a dry dense sand layer and supporting single or double degree of freedom structures. The model is excited with and without structures using 12 sinusoidal waves as input base accelerations with constant amplitudes of about 1.5 m/s2 and varying frequencies ranging from 1 to 12 Hz. All the tests are conducted with the centrifugal acceleration of 40G. The obtained results provide a clear insight as to the distinct role of inertial and kinematic interactions as well as the combined effect of these two interactions on the motion of the pile head by identifying the fundamental frequencies that dominate the response not only for single degree of freedom structure but for double degree of freedom as well. The role of the frequency content of the input motion on the development of kinematic and inertial dynamic pile bending is also investigated.