Cyclic Undrained Triaxial Behavior of Sand by a Cooperative Test Program in Japan

The results of a round-robin cyclic undrained triaxial test program using Toyoura Sand are reported. Toyoura Sand, which is a poorly-graded fine sand consisting of subangular to angular quartz-rich particles, has been widely used in Japan for the study on sand liquefaction. The cooperative tests were carried out by thirty seven laboratories in Japan following the specified test procedures. The test results showed that the cyclic triaxial strength increases noticeably with the decrease in the specimen diameter probably due to the increase in membrane penetration effects. The cyclic deformation and strength characteristics were also strongly influenced by deviation from the uniformity and symmetry of cyclic deviator stresses. It was found that pertinent specifications of test procedures are essential to reduce effectively unaccountable scattering in cyclic undrained test data to a small value.