To improve knowledge of the quartz sand used in analogue modeling, two laboratory tests were carried out to investigate the frictional properties of colored sand. The first one estimated the coefficient of internal friction from the reverse fault dip simulated in a pack of different colored dry sand layers. The second test consisted of measuring stress-strain curves separately for different colored sand using a ring-shear tester. The coefficient of internal friction determined from fault dips is significantly lower and less precise than that determined on the same material with a ring-shear tester. Comparisons with previous granular material tests reveal that although our ring-shear test results are high, they are within the range of values reported in literature. Our results also show that natural and colored sands have different angles of internal friction, and that the Acrilex dye produces a distinct mechanical behaviour for different colored sand. The variation is related to the chemical composition of sand dyes and should be carefully evaluated in future sandbox experiments.
Coefficient of internal friction; quartz sand; analogue experiments; ring-shear tester
