Mechanisms of extreme rainfall-induced seepage failure and an anchored monitoring model for weathered rock slopes using intelligent terminal structure bolt sensors

The weathered transition zone in rock slopes is a geological interface characterised by heterogeneous development of joints and fractures within the rock mass. This structural heterogeneity can lead to the accumulation of pore fluids at the weathering interface under extreme rainfall, resulting in considerable hydro-mechanical damage. Therefore, monitoring the stability of this interface is crucial for assessing the overall stability of rock slopes. To address the monitoring challenges posed by extreme rainfall-induced instability at rock slope weathering interfaces, this study conducted seepage failure modelling experiments and developed an anchored monitoring model. Temporal relationships among slope displacement, pore water pressure and rock bolt axial force were analysed using the monitoring principles of intelligent terminal structure sensors integrated within slope anchoring systems. This analysis enabled the establishment of monitoring and early warning criteria based on the pore pressure gradient and rock bolt axial force at the weathered interface. Thereafter, the proposed early warning model for the weathered transition zone was validated through numerical simulations. This study provided quantitative criteria for the stability monitoring and early warning of rock slope weathering interfaces under extreme rainfall conditions.