Author(s): S. M. Cameron; B. W. Melville; S. E. Coleman
Linked Author(s): Bruce W. Melville
Keywords: Rock Erosion; Fractured rock; Protrusion; Erodibility; Critical shear stress
Abstract: Laboratory experiments, simulating the erosion of blocks of fractured rock, were undertaken to investigate the role of protrusion and block dimensions on the critical shear stress for entrainment of prismoidal shaped blocks. Results indicate that dimensionless shear stress (θc), particle protrusion (P) and the streamwise particle dimension (L1) are the significant variables defining particle erodibility for prismoidal shaped particles. The way in which a particle is restrained by the surrounding bed, and the mechanism of entrainment possible for a particle is a further parameter governing particle stability with particles embedded within a cavity and requiring vertical translation for entrainment observed to have greater stability than particles that can become entrained by a rotation mechanism. Overall, the tests indicate that the critical dimensionless shear stress θc for entrainment of prismoidal particles can be predicted by θc =-3.0x10-3+7.5x10-3 (P/L1) -0.5 for a rotational entrainment and by θc = 5.5x10-3+6.0x10-5 (P/L1) -2 for entrainment requiring vertical translation.
Year: 2003