The collision and fragmentation patterns of rockfalls under the influence of joints were studied through physical experiments. Based on indoor collision tests

the discontinuous deformation analysis (DDA) parallel computing method was used to simulate the impact-collision-fragmentation process of rockfalls. The main focus is on discussing the influence of the angle between the joint and the slope

the connectivity rate k of the joint

and the impact velocity V of the rockfall on its crushing characteristics. The ratio of the surface area of the rockfall to its initial surface area is used as a quantitative measure of the degree of fragmentation

with a larger indicating a higher degree of fragmentation. The research findings are as follows: 1) increases with k; under high-velocity impact conditions

the  value at k = 0.75 is 1.2 times that at k = 0.25. 2) When k = 0.25

does not vary significantly with ; however

when k = 0.50 and 0.75

decreases as increases. 3) The value under high-speed impact (6.8−7.4 m/s) is 1.5 times higher than that under low-speed conditions (3.5−4.5 m/s). 4) As the single-joint connectivity rate k of the rockfall increases from 0 to 0.75

the energy recovery coefficient exhibits a decreasing trend

with its value reduced by 1.6 to 1.9 times. 5) With the increase in impact velocity

the energy recovery coefficient of the rockfall gradually increases with the increase in joint angle

up to 1.6 times. 6) The fracture characteristics and degree of fragmentation obtained through numerical simulation and indoor collision tests are basically the same. An increase in the single-joint connectivity rate and the angle between the joint and the slope surface affects stress propagation and alters the fracture characteristics of the specimens. 7) When a multi-jointed rockfall is impacted and broken

the cracks do not extend along the outline of the joint setting and do not intersect with joints far from the center of the rock. The velocity of the debris after impact is slightly lower than that before impact. This study has certain reference significance for revealing the collision and fragmentation patterns of rockfalls under the influence of natural joints.