Liquefaction of K0-Consolidated Sand Under Cyclic Rotation of Principal Stress Direction With Lateral Constraint

Abstract

Multiple series of cyclic loading tests with continuous rotation of principal stress direction were carried out on samples of Toyoura sand compacted to different relative densities under different initial stress ratios K0 using a triaxial torsion shear test apparatus. In order to reproduce the wave-induced stress conditions occurring in an anisotropically consolidated soil element in the seabed deposit, the K0-consolidated laboratory test specimen was subjected alternately to the triaxial mode and to the torsional mode of cyclic alteration thereby producing a continuous rotation of principal stress direction. In addition to this, it was considered necessary to perform the cyclic loading test such that the progressive buildup of lateral strain in the sample is inhibited in order to simulate the actual strain condition in the field. The condition of no lateral strain was imposed on the test specimen by reducing the vertical stress at the end of each cycle of the cyclic stress application. The results of such tests indicated that, for all densities of the samples tested, the effects of the initial stress ratio Ko on the cyclic strength can be taken into account through its influence on the mean principal stress.