Study on the equivalent stiffness of limestone particles in single particle crushing test based on particle strength and specific fracture energy

Particle breakage can alter the gradation of soil, reduce the interparticle contact friction induced by shear, and serve as a primary cause of deformation in geomaterials, significantly influencing their engineering mechanical properties. The singleparticle crushing test is an essential test method for investigating particle breakage and strength. However, merely analyzing particle strength neglects the deformation information during the crushing process, leading to an inability to accurately characterize the strain state before the particle's overall breakage. In this study, single-particle crushing tests were designed and conducted to analyze the particle strength and specific fracture energy of limestone particles. Based on the analytical results, an equivalent stiffness was formulated. By introducing the concept of equivalent stiffness, the distribution of specific fracture energy was transformed into a particle strength distribution. The validity and reliability of this conversion method were verified, demonstrating its effectiveness in statistically characterizing different stress-path features of particles. This study reveals that the equivalent stiffness of 10-20 mm Baihetan limestone particles in single-particle crushing test is 4.7x106N/m. This result offers a reference value for associated numerical modeling and can inform the corresponding engineering design.