 Based upon these favorable conditions for soil nailing stiff to hard fine-grained soils which include stiff to hard clays, clayey silts, silty clays, sandy clays, and sandy silts are preferred soils.Sand and gravels which are dense to very dense soils with some apparent cohesion also work well for soil nailing.Weathered rock is also acceptable as long as the rock is weathered evenly throughout (meaning no weakness planes).