An Experimental Study on Effect of Boundary Condition on Particle Damage in Shear Zone of Crushed Sand

Various factors influence particle breakage in the shear zone of silica sands, including particle shape characteristics, loading path, shear displacement, normal load, initial density, and boundary conditions. The present study focuses on particle breakage occurring in the shear zone of a crushed silica sand under shear loading. Several ring shear tests were conducted to measure shear stress‐displacement response of a sand. Grain‐size distribution curves of the original sand (prior to shearing) and the sheared sand from the shear zone are then compared. The mechanism of particle breakage is determined by a thorough examination of particle damage under “constant normal load” and “constant volume” tests, considering both loose and dense samples. The results show that void ratio is the dominant factor in particle breakage. On the other hand, it is observed that particle breakage resulting from particle shape properties accrues within the initial loading stages. It is observed that the boundary condition also affects the magnitude of particle breakage; that is, particle damage under “constant normal load” boundary condition is found to be significantly higher than that under “constant volume” condition for the same initial normal stress and void ratio.