Abstract:
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The effects of both translational and rotary shear on particle transport Ander coupled shear-flow test conditions in a single rouge rock fracture were numerically investigated in this thesis. A pair of digitalized surfaces of a 250x250 mm concrete rough fracture replica were numerically manipulated to simulate the translational and rotary shearing processes of the sample, using Finite Element Method (FEM). Different fluid flow situations were cosidered. For the translational shear three different flow patterns-unidirectional, bi-directional and radial-have been taken into account. For rotary shear, only the radial flow patterns have been considered. Furthermore, the effect of the fracture surface roughness on the aperture and transmissivity fields was evaluated using semi-variograms.The results of flow and particle transport simulations show that translational shear yields a channelling effect in the direction perpendicular to shear direction, creating high transmissivity channels through which the particles travelling in this direction can travel fast and without being delayed by bypassing low transmissivity areas. Bi-directional flow patterns show clearly the shortcomings of the conventional shear-flow tests in the laboratory with a unidirectional flow. In radial flow patterns, while translational shear generates an anisotropic particle transport behaviour with faster transport perpendicular to shear direction, rotary shear presents isotropic flow field and particle paths in all directions. |