Effects of coupled-scaled geogrid and gravel on the mechanical behaviour of lightly cemented gravel under compressive loading

This study investigates the coupled effects of scaled geogrid axial stiffness and maximum particle size on the mechanical behaviour of geogrid-encased lightly cemented gravel materials (LCGMs). Unconfined compression tests were conducted on specimens with four maximum particle sizes and corresponding scaled geogrid axial stiffnesses at cement contents of 1 and 2% under controlled bulk density. The results show that strength and stiffness consistently decreased with increasing maximum particle size at both cement contents, with power-law-based extrapolated estimates indicating maximum reductions of approximately 65 and 70%, respectively, relative to the smallest particle size tested. In contrast, Poisson’s ratio and failure pattern were only marginally affected. Geogrid reinforcement provided an approximately consistent strength enhancement across the investigated scaling factors, indicating no clear interaction between geogrid scaling and particle-size scaling. Empirical power-law relationships were developed to describe the particle-size dependence of the mechanical properties of LCGMs and to estimate the corresponding properties at the prototype particle size.