Interpretation of the data of soil shear tests

Abstract

1. It was shown experimentally that the shear planes in a soil sample in a shear box in the general case do not coincide with the plane of contact between the shear rings (design shear plane). 2. The shear strength of noncohesive soils (dense and loose) increases monotonically with an increase of displacement of the shear rings and has an ultimate value determined by the value of the angle of internal friction. The value of the angle of internal friction is determined by the soil composition and does not depend on its density. The orientation of the shear planes depends on the soil density. 3. Peak and residual shear strength are characteristic for soils with sensitivity. The residual strength in this case is determined only by the forces of internal friction at a constant value of the angle of internal friction and cohesion equal to zero. 4. The values of the angle of internal friction according to the results of its determination in triaxial apparatus and a shear box are equal among themselves. When determining the angle of internal friction in a shear box an additional cheek of the coincidence of the shear planes with the design shear plane is necessary.