The analysis of slippage failure of the HuangNanBei slope under dry-wet cycles in the three gorges reservoir region, China

The purpose of this paper is to study the sliding failure of the jointed rock slope caused by the degradation of rock mass mechanics under dry-wet cycles. Based on the mechanical parameters of reservoir limestone obtained under different numbers of dry-wet cycles, a discrete element approach was adopted to analyze the slippage failure mode of HuangNanBei slope in the Three Gorges Reservoir Region. The Barton-Bandis nonlinear strength criterion for discontinuities was used to improve the Mohr-Coulomb (M-C) sliding model, and the modified M-C sliding model could make the shear strength parameters of the discontinuities change with the stress state. Under the modified model, there was a tendency for disintegration between blocks in the process of slippage, which was more in line with the actual working conditions and proved the validity and necessity of this model. Furthermore, the slip rate increased with the increase of dry-wet cycles, and the increase trend had not slowed down after 30 dry-wet cycles. The cumulative displacement from 0 to 30 dry-wet cycles was obtained by changing the mechanical parameters of the discontinuities every 10 steps to simulate each dry-wet cycle. The pattern of the cumulative displacement curve was consistent with the slip curve of the 30th dry-wet cycle, which indicated that the degradation of the rock mass mechanics is irreversible. Consequently, strengthening the hydro-fluctuation belt is of great significance for disaster prevention and control in the reservoir region.