Shaking table test and numerical simulation on a combined retaining structure response to earthquake loading

The combined retaining structure is widely used in high slope supporting engineering. In this paper, shaking table test and numerical simulation are carried out on the seismic response of a combined retaining structure where a gravity wall and an anchoring frame beam are used as a lower structure and an upper structure, respectively. The shaking events of Wenchuan, Da-Rui and Kobe ground motions with different amplitudes are applied in both horizontal and vertical directions. The horizontal and vertical acceleration responses are studied in time domain and frequency domain based on shaking table test, and the results are compared with those obtained from numerical simulation. The axial stress response of anchor and the element state of combined retaining structure subjected to earthquake loading are supplemented and studied by using numerical simulation. Both horizontal and vertical acceleration responses near the bottom of frame beam are significantly magnified, which results in a dramatic increment in acceleration amplification. The acceleration response behind the frame beam is more intensive than that at the back of the gravity wall. The high-frequency component of seismic ground motion is weakened by the combined retaining structure, and the vertical acceleration response presents a wider frequency band. The axial stress of anchor is greatly increased by seismic excitation, and the increment is mainly induced within the excitation period of great acceleration amplitude. Shear failure, tension failure, or both are observed at different positions of combined retaining structure during seismic excitation.