Abrasion damage of geogrids induced by turbid flow

A cylindrical chamber generating a forced circular turbid flow is developed to study the abrasion damage of three woven geogrids. It is shown that this chamber creates consistent turbid flow velocities and particle concentrations, and is potentially useful as an accelerated abrasion damage test based on the results of laboratory tests and pilot seashore protection tests. Two types of damage on the strands of woven geogrids are identified: one is abrasion against the surface of strands in the flow direction; the other is the cutting of strands normal to the flow direction. Test results also show that the strength reductions increase with test duration, while the strength reduction rates decrease as the test duration increases. The change in particle angularity may account for the decreasing strength reduction rates observed in the tests. An epoxy-coated geogrid (GRID 6) appeared to have higher resistance against abrasion than a polyvinylchloride-coated geogrid (GRID 2) indicating that the use of new coating materials to increase the durability of woven geogrids in turbid flow environments is possible. This also suggests a need for establishing cost-effectiveness and robustness evaluation systems for coating materials.