Erosion of Compacted Xanthan Gum–Treated Sand–Silt Mixtures

Erosion of compacted, xanthan gum–treated sediments is discussed. Experiments were conducted in a straight laboratory flume with sand and sand–silt mixtures with silt content of 10% and 25% and xanthan gum concentrations equal to 0.05%, 0.10%, and 0.15% all relative to the mass of sand. Modes of erosion observed in the experiments were surface and mass erosion, with the transition from one mode to the other occurring when shear velocity was equal to 0.015 – 0.019 m / s . Typical features of mass erosion in xanthan gum–treated sand were deformation of the sample surface and detachment of chunks made of xanthan gum–treated sediment. Results also showed erosion rates decreasing in samples treated with relatively high xanthan gum concentrations. The presence of silt further increased resistance to erosion, especially at the highest xanthan gum concentration when a spongelike surface formed and delayed the onset of erosion. In summary, experiments revealed that xanthan gum reduced erosion of compacted, noncohesive soils. It altered the mechanics of sediment transport, transitioning from surface erosion to mass erosion as shear velocity increased. These findings have implications for the use of xanthan gum in soil stabilization and erosion control.