Volume 29, Issue 3 (May 2001)
Formation of Shear Bands in Model Ground Composed of Aluminum Rods Beneath a Footing
In this study, a series of bearing capacity tests were carried out on a model ground composed of aluminum rods in order to investigate the initiation and development of shear bands during loading. This paper describes the test apparatus, the methods of testing and data treatment, and some of the test results. Two types of model grounds were prepared depending upon whether the aluminum rods used were single-diameter or two different diameters. During the loading test, by utilizing both front and back of the test apparatus, detailed observations were made on the global deformation of the model ground, on the translational and rotational movements of selected aluminum rods, and on the change of void ratio. It is shown that, in the case of the single-diameter aluminum rods, the slip surface was observed and that dilatancy behavior was noted at the boundary. In the case of the aluminum rods with two different diameters, discontinuous shear bands defining a so-called plastic flow zone were observed, which were initiated at the bottom corners of the footing and extended diagonally downwards. The rotational behavior of the rods differed inside and outside the plastic flow zone, particularly near the boundaries.