The breakage behavior of granular materials is prevalent across various fields and significantly impacts the mechanical properties of granular materials. A substantial amount of research on particle breakage behavior relies on reasonable calculation methods for breakage rate. This article proposes a calculation method for particle breakage rate based on particle volume as the fundamental parameter

addressing the current limitation of existing methods in accurately evaluating the breakage rate of irregular particles

exemplified by coral gravel. It improves upon the existing Hardin breakage rate calculation formula

which is based on particle size

to better assess the breakage rate of irregular particles. Breakage tests of coral gravel with different shapes were designed and conducted to conduct reliability validation of the aforementioned theoretical formulas

and the causes of errors generated by traditional methods were analyzed. Through experiments

the breakage rate values of particles with different shapes under different pressures and algorithms were obtained. Meanwhile

combining stress

deformation

and image observations from the experimental process

the fragmentation thresholds of coral gravel in three shapes—sheet

block

and rod—were determined

revealing the evolution characteristics of fragmentation modes exhibited by particles with different morphologies during the pressure change process.