Investigation on the dynamic cumulative damage mechanism and stability of bedding rock slope under the deterioration of rock mass in the hydro-fluctuation belt

The deterioration of rock mass in the hydro-fluctuation belt and reservoir-induced earthquakes in the Three Gorges Reservoir Area (TGRA) have great impact on the stability of bedding rock slope. The cumulative damage mechanism and stability of bedding rock slope under the deterioration of rock mass in the hydro-fluctuation belt, when subjected to repeated seismic loads, were investigated using the shaking table model test and Universal Distinct Element Code (UDEC) numerical simulation. Under the continuous action of seismic loads, the peak ground acceleration (PGA) amplification coefficient clearly weakens; the cumulative displacement, pore water pressure and earth pressure of the slope show a change trend of increase, increase and decrease, respectively; the damping ratio and damage degree (DG) of the slope increase, while the natural frequency of the slope decreases gradually; the nonlinear cumulative damage mechanical models of the slope in the stages of microseism—small earthquake action and strong earthquake action can be characterized by the cubic function of “S-type” and the exponential function of “steep rise type,” respectively. Based on the good agreement between the experimental observations and numerical simulation results, the evolution process of the dynamic cumulative damage—instability and typical failure modes of the slope (including the hydro-fluctuation belt) was observed. Furthermore, the stability of the slope increases with the decrease of the slope height (A), slope angle (B), seismic load amplitude (C), seismic load frequency (D), or deterioration depth of rock mass in hydro-fluctuation belt (E), while it decreases with the increases of the strength degradation ratio of the rock discontinuities in hydro-fluctuation belt (F); the ranking of sensitivity of the mentioned-above influence factors is C > A > D > E > B > F according to the orthogonal analysis method (OAM).