THE TESTING OF SOILS UNDER CONDITIONS OF PASSIVE STRESS RELIEF

Many soil mechanics problems such as excavations, borings and tunneling induce stress relief in the surrounding ground. The effective stress paths associated with such problems are complex and entail reductions in the principal efective stresses with increases in effective stress ratio often leading to local zones within which the soil is at limiting equilibrium. In this note a simple technique is described for carrying out tests in which the soil is maintained in a state of passive failure while the principal effective stresses are steadily reduced to very small values under controlled axial deformations.