Particle size effect on the mechanical behaviour of coral sand - geogrid interfaces

Particle size distribution (PSD) of coral sand is a critical factor that influences the mechanical properties at the coral sand-geogrid (CS-GG) interface, which is affected by both particle breakage and various temperatures. However, relevant researches are scarce currently. This study conducts a series of large-scale interface shear tests on coral sand with three PSD ranges (0.25∼1mm, 1∼2mm, and 2∼4mm) at varying temperatures (5°C∼80°C). Experimental results demonstrate that the I B value at the CS-GG interface ascends and then descends with the increase of PSD from 20°C to 40°C. The I B value at the interface descends and then ascends with the increase of PSD from 60°C to 80°C; The PSD curves at the interface indicate that the particle breakage degree of coral sand increases with rising temperature (5°C∼40°C); The larger PSD of coral sand, the smaller fractal dimensions (D) of the interface; A mathematical formulation of the relationship between the relative breakage rate (B r ) and the D value at interfaces is presented, which considers temperature effects; The relationship between the total input energy (E) and the B r value has been expressed by empirical formulations with different PSD ranges, where the fitting curve for 2∼4 mm coral sand exhibits a hyperbolic pattern.