Abstract
Cyclic torsional shear tests on hollow cylindrical specimens were conducted to investigate the effects of degree of saturation on the undrained cyclic shear strength (liquefaction resistance) of air-pluviated Toyoura sand at a relative density of 60 percent. The tests showed that (1) the liquefaction resistance increased significantly with a decrease in degree of saturation to such an extent that the liquefaction resistance at 70 percent saturation was about three times that at full saturation ; (2) the liquefaction resistance also increased with a decrease in B-value, although a near-zero B-value was required for a significant increase in the liquefaction resistance; and (3) the cyclic shear behavior of the partially saturated sand resembled that of denser saturated sand, exhibiting high strength as well as stable deformation characteristics. Based on the above findings it is concluded that a reduction in degree of saturation can be an effective means to increase the liquefaction resistance of loose sands.
