Investigation into a homogenous step-like rock slope response under wide-frequency seismic loads using a large-scale shaking table

This paper studied the dynamic response of the homogeneous step-like rock slope under wide frequency and amplitude through a large-scale shaking table test. A homogenous rock slope with a length of 3.50 m, width of 0.68 m and height of 1.20 m was constructed in a rigid steel box. Results indicate that acceleration amplification factor in horizontal direction (AAF-X) along the slope surface is amplified with the increase in the slope height when loading frequency ≤ 45 Hz, while AAF-X decreases first then increases when loading frequency is 60 Hz and 75 Hz. The acceleration amplification factor in vertical direction (AAF-Z) increases first and then decreases with the increase in the slope height. The resonance frequency of slope near the slope crest decreases from 61.37 to 58.12 Hz, while the damping ratio increases from 5.8 to 8.8%, as the loading amplitude increases from 0.1 to 0.5 g. The AAF reminds linear increase with a loading amplitude of up to 0.4 g while decreases when the loading amplitude becomes larger than 0.5 g. It reveals that the loading amplitude has a “double-effect” on the seismic response of the homogeneous rock slope. That is, on the one hand, the larger the loading amplitude, the stronger the acceleration intensity, the greater deterioration of rock slope structure or material and the larger damping ratio of the slope; on the other hand, more energy will be dissipated due to plastic deformation or particle friction of high damping ratio and weaker slope structure. Such test result can be used for understanding the dynamic instability mechanism of the homogeneous slope in the field.