Influence of fine particle content on the mechanical behaviour of river gravel material

The river gravel foundation is a typical complex foundation condition, which is characterised by discontinuous gradation, loose structure, and complex physical and mechanical characteristics. The fine particle content is an important factor that influences the mechanical behaviour of the gravel materials. This paper investigates the influence of fine particle content on the mechanical behaviour of river gravel materials. The triaxial shear tests were conducted on the gravel materials with different fine particle contents of 21.5%, 27.5%, and 33.5% under different confining pressures. The influence of fine particle content on the strength and deformation properties of the river gravel materials was analysed. And the influences of fine particle content on the particle breakage were discussed on the basis of the relative breakage ratio and relative breakage parameters indicators. The results indicate that the river gravel material exhibits a strain-softening behaviour. The stress-strain curve of the river gravel material exhibits linear stage, yield stage, and softening stage. The material peak strength increases with the increase in the fine particle content. Under low confining pressure conditions, the river gravel materials exhibit a pattern of initial shear contraction followed by shear dilation. Under high confining pressure conditions, the material mainly exhibits shear contraction characteristics. The volumetric strain decreases with the increase of the fine particle content. The particle breakage indicators decrease with the increase of the fine particle content.