Effect of particle size distributions on the mechanical behavior and particle breakage of coral sands

A series of tests was carried out to study the effect of particle size distribution on the mechanical behavior and particle breakage of coral sand. The tested materials had the same origin, and ten different particle-size distributions were used in the tests. Notably, oedometric and isotropic compression tests and monotonic drained and undrained triaxial tests were conducted. Additionally, a simple particle breakage model considering particle size distribution based on the input energy was proposed. The test results showed that the oedometric and isotropic compressibilities of coral sand decreased with increasing uniformity coefficient C_u but increased with increasing mean particle size D₅₀ and curvature coefficient C_c. The effective internal friction angle φ, maximum dilation angle ψ_max and secant modulus E₅₀ of coral sand all increased with increasing coefficient \(\sqrt {C_{u} /C_{c} }\) but decreased with increasing mean particle size D₅₀. The relative density, particle breakage, confining pressure and particle size distribution had negligible influences on the residual friction angle of coral sand. In addition, under the same input energy, the relative breakage B_r decreased with increasing uniformity coefficient C_u, increased with increasing mean particle size D₅₀ and was basically independent of the curvature coefficient C_c. The proposed particle breakage model could effectively predict the particle breakage trends of coral sands from the same source but with different particle gradations at the stress level used in this study.

Graphical Abstract