The high-bench dump of wide-graded waste rock formed by slope-to-the-bottom has obvious particle size grading characteristics. Traditional stability analysis methods usually simplify it to multi-layer isotropic homogeneous soil

and substantially ignore the uneven and random distribution of each particle group in the dump. This makes it difficult to obtain a reasonable conclusion about the slope stability. Relying on the high-bench dumping site of a copper mine in Jiangxi

with the help of self-edited cellular automata program EPOHHM

five groups of narrow-graded coarse-grained soils are used to characterize the particle size grading phenomenon of high-bench dump

and to simulate the non-uniformity and randomness of the granular media material in each particle group. The displacement field and plastic state of the dump site under different working conditions are analyzed

and the safety and stability of the dump site slope under different dumping modes are systematically discussed. A detailed analysis method for the stability of a high-step dump with wide-graded waste rock is proposed. The research results show that the “tension-shear” failure occurs in the dump; the middle-upper part of the soil has an arc-shaped landslide trend

the deformation of the lower part manifests as settlement

and the top platform produces tensile and shear cracks. Considering only the mechanical strength of the granular media material

increasing the content of coarse particles(d>100 mm) at the bottom plays a significant role in stabilizing the dump. The "full section height dump of single-step" dumping mode is more conducive to the safety and stability of the high-bench dump with wide graded waste rock than "full overlay dump of multi-step". The research results will provide guidance for ensuring the long-term safety and stability of the dump with obvious particle size grading

and also provide a reference for the future analysis of similar engineering problems.