Particle size effect on the mechanical behavior 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, affected by both particle breakage and various temperatures. However, relevant research is currently scarce. This study conducts a series of large-scale interface shear tests on coral sand with three PSD ranges (0.25 ∼ 1 mm, 1 ∼ 2 mm, and 2 ∼ 4 mm) at varying temperatures (5°C ∼ 80°C). Experimental results demonstrate that the IB value at the CS-GG interface ascends and then descends with the increase of PSD from 20°C to 40°C. The IB 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 (Br) and the D value at interfaces is presented, which considers temperature effects. The relationship between the total input energy (E) and the Br 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.