Sand Liquefaction Under Cyclic Loading Simple Shear Conditions

TLDR

The study suggests that simple shear tests underestimate liquefaction stress by 40–50% and recommends applying a similar correction factor to laboratory data used for field analyses. Results show that liquefaction under cyclic simple shear occurs at about 35% of the stress needed in triaxial tests, with similar qualitative behavior and negligible frequency effects between 1/6 and 4 cps.

Abstract

Test data to compare the resulting behavior with that observed under cyclic loading triaxial test conditions are presented. It is concluded that the liquefaction characteristics observed in the two types of tests are qualitatively similar. However, under cyclic simple shear conditions, which provide a close simulation of the stresses induced under field conditions, the cyclic shear stresses required to cause liquefaction were only about 35% of those determined by more approximate triaxial test procedures. It is suggested, however, that limitations of the simple shear test procedure induce liquefaction at stress levels perhaps 40% to 50% lower than those corresponding to actual field conditions, and that a correction factor of this order of magnitude should be applied to laboratory simple shear test data intended for use in the analyses of field problems. The test program also showed that frequency effects, within the range from 1/6 cps to 4 cps, are small.