The Effects of Suppression of Dilation on the Shear Strength of Sands

It is known that peak angle of friction (_p^') for sands decreases as normal stress increases until critical state. The suppression of dilation of sands as normal stresses increase results in particle breakage, which contributes to this reduction in peak strength. There is still disagreement regarding how suppression of dilation and particle breakage affects sands critical state angle of friction (_cs^'). A total of 178 direct shear tests on three different sand types were completed to investigate the effects of suppression of dilation on the shear strength of sands, as well as effects of particle size, shape and sample size. _p^' decreased with suppression of dilation as expected. In general, _cs^' decreased by 7-9.5o as dilation was suppressed, and was found to decrease with increasing particle size. Particle shape showed less influence on _cs^' as dilation was suppressed. The effects of particle shape and sample size on _cs^' were more difficult to quantify.