Investigation on dynamic cumulative damage mechanism of the dangerous rock slope including deteriorated rock mass in hydro-fluctuation belt

The shaking table model test with a geometric similarity ratio of 1:100 was constructed to investigate the stability of the typical dangerous rock slope in the Three Gorges Reservoir area under the influence of rock mass deterioration and reservoir-induced earthquakes. The whole process of dynamic cumulative damage, instability failure, and the response law of the dangerous rock slope including deteriorated rock mass in the hydro-fluctuation belt were discussed. The results demonstrated that the whole process can be described as the cumulative damage in the slope -> the cracks development -> the penetration of secondary joints and deep large cracks -> the instability toppling. At the same time, the rock mass on the surface of the hydro-fluctuation belt begins to loosen and fall, resulting in the formation of a seepage network, seepage channels, and cavities within the slope. As ground motion continues, the dynamic response of the dangerous rock mass exhibits a typical "elevation effect" and "surface effect". The cumulative displacement on the dangerous rock slope surface increases continuously, while the pore water pressure within the hydro-fluctuation belt increases overall. The horizontal and vertical earth pressure of the dangerous rock slope initially increase and then decrease, and the natural frequency and the damping ratio of slope decrease and increase, respectively, throughout the entire stage. Before the end of the small earthquake stages and at the strong earthquake stages, the damage degree curve of the dangerous rock slope follows an "S" type distribution and an exponential distribution.