Shear Strength Tests for Coarse Granular Backfill and Reinforced Soils

In order to overcome the limitations of the current standard small direct shear box in testing the shear strength of coarse granular backfill materials, a large direct shear apparatus (1000 by 1000 by 940 mm) was constructed at Carleton University and a series of direct shear tests were conducted with coarse granular soils. In addition, several direct shear tests on soils reinforced with geogrids were also conducted, and the shear strength parameters of the composites were compared with those of natural soils. It is shown that the controlled large direct shear test, though time consuming, provided a useful way of evaluating the behavior of the natural granular soils and reinforced soils.