Cumulative damage evolution of jointed slopes subject to continuous earthquakes: Influence of joint type on dynamic amplification effect and failure mode of slopes

This work investigates the dynamic response characteristics and cumulative damage evolution of jointed slopes under continuous earthquakes. Three jointed slope discrete-element models were created using a new fracture formation method to avoid particle overlap. The effects of joint types on dynamic amplification and failure mode are investigated. The results show that joints amplify the seismic response, with bedded jointed slopes exhibiting the highest magnification effect, followed by parallel jointed slopes and anti-dip jointed slopes. Cracks gradually increase under continuous earthquakes, with an increasing rate characterized by increase-decrease-increase-decrease. The failure scale of the bedded jointed slopes is the largest, followed by the parallel jointed slopes, and the anti-dip jointed slopes have the smallest failure scale. Seismic cumulative damage evolution encompasses stages of local damage (priming effect), expansion of local damage (accumulative effect), slip body formation, and instability (acceleration effect). Discontinuous joints affect the damage characteristics and instability modes of slopes by controlling fracture initiation and expansion. They have minimal impact on intrinsic frequency and frequency spectrum characteristics but significantly affect marginal spectrum characteristics. This work provides insights into the behaviour of jointed slopes under continuous earthquakes and the influence of joint types on their cumulative damage evolution process.