Abstract: Based on the typical loess plateau slope of Kongtong district, Pingliang city, a 1:25 large-scale shaking table test is designed and accomplished using the conceptual model of the slopes with or without cracks. On the premise of satisfying the similarity principle, the dynamic response characteristics of model slopes of two kinds of structures are analyzed by inputting seismic waves in horizontal direction and vertical direction with different amplitudes. Results show that the horizontal and vertical seismic waves have obvious nonlinear amplification along the slope surface and the internal vertical direction, which reach the maximum value at the top of the slope. Under the horizontal seismic waves with the same amplitude, the acceleration amplification coefficient of the slope surface and section 4 are greater than that of the slope without crack at the same elevation in the middle and upper part of the slope, while in section 1, the amplification coefficient of the crack slope is smaller than that of the crack-free slope. After the seismic wave propagates through the slope soil, the predominant frequency changes significantly. With the increase of elevation, the slope will manifest selective amplification on middle and high frequency bands, which is more obvious on the side of fissure slope. Moreover, as the amplitude of seismic wave increases, the superior frequency transfers to the low frequency direction. However, the remarkable frequency attenuation is not obvious under the vertical seismic wave.

Key words: loess tableland slope, shaking table test, crack, acceleration dynamic response, spectrum analysis