关键词: 振动台试验, 顺层岩质斜坡, 软弱夹层, 动力响应

Abstract: Tens of thousands of ancient landslides and potential landslides are distributed along the Three-rivers basin in the southeast of Qinghai-Tibet Plateau, posing a severe threat to the Sichuan-Tibet railway under construction. A shaking table model test was performed to study the dynamic response of bedding rock slope with weak interlayer under strong earthquake. The influences of different ground motion parameters, input wave types, and weak interlayer on slope dynamic response were analysed. The test results show that the natural frequency of the slope decreases gradually with the increase of the number of input seismic waves, and the vibration intensities of 0.3g and 0.6g are the critical dynamic conditions for crack initiation and instability of the slope. There is an obvious elevation effect on the slope, and the acceleration amplification factor increases first, then decreases, finally increases along the slope surface, and is larger at 1/4 of the slope height and the top of the slope. The vertical acceleration amplification factor inside the slope increases linearly with elevation. The frequency has a great impact on the dynamic amplification response of the slope. The slope does not significantly amplify low-frequency seismic waves, and even inhibit them. With the increase of frequency, the dynamic amplification effect of slope becomes more and more prominent. As the amplitude increases, the acceleration amplification factor firstly increases and then decreases, finally reaches the maximum value at the vibration intensities of 0.3g–0.4g. Under the excitation of different types of seismic waves, the amplifying effect of slope on natural waves is higher than that on synthetic waves. The existence of a weak interlayer amplifies the input seismic wave markedly, and the fast Fourier transform (FFT) shows that the sensitivity of positions of the weak interlayer to frequency bands of input seismic waves differs. This experiment reveals the dynamic response law of bedding rock slope with weak interlayer under strong earthquake action and provides a basis for further study on the failure mechanism and prevention of slope.

Key words: shaking table test, bedding rock slope, weak interlayer, dynamic response