CYCIC BEHAVIOUR OF SAND: SEQUENTIAL INCREASING PEAK STRESS RATIO AND a, BEHAVIOUR

The strength and deformation behaviour of dense and loose samples of Leighton Buzzard sand were examined by means of cyclic biaxial loading tests in which the stress orthogonal to the plane of strain was initially applied at different magnitudes of a,=۲۰, ۵۰ and ۸۰ kPa. The experimental results showed that the general trend of volume change during cyclic stressing is to cause densification and build of structure (fabric force). Also it was revealed that after many cycles the values of az are independent of their initial values and settle very close to the mean principal biaxial stress