Shaking Table Test on Time-History Response of Rock-Socketed Pile Group Under Strong Earthquake

Due to the 'pile groups effect',pile groups show dynamic time-history response law different from the single pile under seismic dynamic load.Through large-scale shaking table model test,5002wave,5010wave,El-Centro wave,and Kobe wave with the intensity of 0.35g are selected to study the time-history response law and fundamental frequency damage of rock-socketed pile groups.The shaking table test results show that the seismic wave spectral characteristics have a significant influence on the dynamic response parameters of rock-socketed pile groups.The pile groups’ peak acceleration under the El-Centro wave is large,and the peak value of the pile top is lagging behind.Under the action of Kobe wave,the horizontal relative displacement of pile top and the peak value of bending moment are large,but they all appear the earliest in El-Centro wave.The bending moment peak values do not exceed its ultimate bending capacity.The fundamental frequency of pile groups does not change obviously,indicating that there is no damage to pile groups under the strong earthquake.Therefore,the seismic performance of rock-socketed group piles can be optimized through seismic waves with different spectral characteristics,and corresponding engineering suggestions can be put forward.