Shear Strength of Uni-Sized Gravels Under Triaxial Compression

Abstract

The strength features of uni-sized gravels in drained triaxial compression tests under a confining pressure of 2 kgf/cm2 (196 kN/m2) have been studied in relation to their grain properties and breakage. Testing materials consisted of two rounded natural gravels and six angular crushed gravels. The measured grain properties were particle shape, roundness, tensile strength and limiting densities. The following main findings are presented. The angle ϕr corrected by Rowe’s theory is closely related to the minimum void ratio. The relationship of the strength component due to dilatancy and interlocking versus Marsal’s breakage factor Bm for the angular materials differs from that for the rounded ones. It is also shown that the dilatancy rate at failure is uniquely expressed by the first author’s parameter Sr. The shear strength of the tested gravels is closely related to the failure probability of grains. Consideration is also given to the compression index under an all-round pressure. In conclusion, in order to consistently rule the tested strength and dialatancy performance, measurements and the consideration of particle properties referred to in this contribution are essential.