Instability mechanism and failure characteristics of underground cavern in block system under the action of seismic waves

Geological discontinuities and excavation surfaces divide the surrounding rock of underground caverns into blocks, whose instability under seismic loading poses risks to both construction and long-term stability. While stress wave propagation in jointed rock masses has been widely studied, the opening and sliding behaviors of rock joints under seismic loading remain insufficiently addressed. This study investigates the sliding instability of cavern rock blocks under the action of seismic waves based on wave propagation theory and Universal Distinct Element Code numerical simulations. The analysis includes the response of a single block under varying seismic wave parameters, e.g., amplitude, frequency, and duration, and the overall failure characteristics of a block system under seismic excitation. Results show that seismic waves can reduce joint friction and alter sliding forces, leading to block instability when sufficient sliding space exists. The sliding behavior is governed by both seismic wave characteristics and geological structure conditions. These findings enhance understanding of failure mechanisms in jointed rock caverns and offer valuable guidance for improving the safety and stability of underground construction.