The Drained Strength of Granular Material

Using the stress dilatancy relation R = DK, the drained strength of granular material is separated into its dilatant and frictional components. The factors influencing the value of 1 ≤ D ≤ 2 and Kμ ≤ K ≤ Kev are assessed theoretically, and experimental confirmation is provided from tests mainly on River Welland sand. These tests include five different sample geometries, and cell pressures up to 1000 p.s.i. (70.3 kg/cm2). The failure criterion is seen to be contained between two limiting types of behavior relevant to dense and loose assemblies. The main ambiguity exists in the case of axisymmetric extension when the strength is seen to be influenced by the sample boundary conditions.