Research on Collapse Characteristics of Bedrock and Overburden Layer Slope under Earthquake Based on HHT

Based on the similarity criterion, the slope model was designed according to the similarity ratio of 1:10 to the prototype for the typical overburden layer slope near Litang-Dewu fault zone along Sichuan-Tibet Railway. The seismic collapse tests of the slope were carried out under Wenchuan-Wolong seismic wave, Kobe seismic wave and El Centro seismic wave. The HHT (Hilbert-Huang Transform) spectrum of displacement response and acceleration was used to study the deformation and failure characteristics of the slope under earthquake. The results show that the slope collapse can be divided into three stages: stable vibration, crack expansion and collapse failure. In the stable vibration stage, the internal force of the slope can counteract most of the ground motion energy and a small amount of elastic displacement occurs in the soil. The HHT spectrum amplitudes of the slope caused by different types of seismic waves are obviously different, and are mainly low-frequency vibrations. In the crack expansion stage, the debris flow appears on the slope surface and the soil mass produces obvious plastic deformation. In the collapse failure stage, the slope collapse is a local effect, and the HHT spectrum amplitude of the collapse adjacent region is widely distributed in the time domain. The collapse is accompanied by a landslide with weak interlayer, and the displacement magnitudes of the slope correspond to those of HHT spectrum amplitudes under different seismic waves. © 2021, Editorial Department of China Railway Science. All right reserved.