AASHTO T215Full Name AASHTO T215 – Standard Method of Test for Permeability of Granular Soils (Constant Head)Scope This method describes a procedure for the determination of the permeability of water through granular (cohesionless) soils in a steady-state condition.Keywords constant head; falling head; permeameter; soil permeability; TrautweinResourcesAASHTO Website Need more info?