The work reported in the literature (see Chapter 2) reveals that the main factors influencing soil residual shear behavior are Atterberg limits, particle size distribution, normal stress, particle shape and shearing rate. The purpose of this chapter is to investigate the extent to which these factors influence the residual shear behavior of soils. This investigation was conducted by means of an intermediate direct shear box. The samples are divided into three groups of mixtures in terms of their composition: (1) a mixture of kaolin, glass sand and glass beads; (2) kaolin, silt, glass sand and glass beads; and (3) kaolin, silt, river sand and crushed granite gravels. These mixtures represent a wide range of natural soils, particularly in terms of particle size and particle shape.