Mechanics of granular-frictional-visco-plastic fluids in civil and mining engineering

The shear stress generated in mine backfill slurries and fresh concrete contains both velocity gradient dependent and frictional terms, categorised as frictional viscous plastic fluids. This paper discusses application of the developed analytical solution for flow rate as a function of pressure and pressure gradient in discs, pipes and cones for such frictional Bingham-Herschel-Bulkley fluids. This paper discusses application of this continuum fluid model to industrial materials like mine and mineral slurries, backfills and fresh concrete tests

Experimental investigation on the effect of wear flat inclination on the cutting response of a blunt tool in rock cutting

A vast majority of experimental researches focuses on the cutting action of a sharp cutter, while there has been limited experimental work devoted to the study of the contact process at the wear flat-rock interface. The specific objective of this study is to determine the effect of the wear flat inclination angle ( β ) with respect to the cutter velocity vector ( vv ) on both the contact stress ( σ ) and friction coefficient ( μ ) mobilized at the wear flat-rock interface. An extensive and comprehensive set of cutting experiments was carried out on thirteen different sedimentary quarry rock samples using a state-of-the-art rock cutting equipment. A unique cutter holder was purposely designed and manufactured along with a precise experimental protocol implemented in order to change the back rake angle and therefore the inclination β by steps of 0.10∘ . The experimental observations confirm the existence of three regimes of frictional contact (identified as elastic, elasto-plastic and plastic) for all rock samples. Further, the results suggest that the scaled contact stress is predominantly controlled by a dimensionless number η=E∗tanβq with E∗ the plane strain elastic modulus and q the rock strength

On the initial non-linearity of compressive stress-strain curves for intact rock

The unconfined compression load-displacement curves for rock samples were described. A series of uniaxial compression tests was performed to implement and compare two different methods of deformation measurements. Stress-strain plots corresponding to these different methods were compared with numerical results. Results concluded the nonlinear effects of the interfaces between the loading platen and the sample or sample and the indenter

An application of linearised dimensional analysis to rock cutting

Three linearized predictive models are presented: one from the sandstone and marble data; one from the sandstone data; and one from the marble data. These three models allow modifications as the experimental program progresses. Further, these models are shown to be useful for predicting the machine reaction forces under a variety of test conditions