Inherent anisotropy of an undisturbed and compacted loess soil

Abstract

This work discusses the result of an experimental study on inherent anisotropy of the loess soil found at Córdoba, Argentina. A cubical true triaxial device provided with flexible boundaries was used and the samples were subjected to an isotropic compression stress path. A brief description of the true triaxial device as well as the procedure for its assemblage and testing procedure is presented. Tests were performed on undisturbed and compacted samples. Undisturbed block type samples were recovered from open trenches. Compacted samples were made either by tamping or static compaction. The effect of compaction method on structural anisotropy was evaluated. Samples were prepared at dry of optimum, optimum and wet of optimum. Isotropic compression tests show that inherent structural anisotropy is found in both undisturbed and compacted specimens. Undisturbed samples are less compressible and develop higher degree of strain anisotropy respect the compacted samples at the same dry unit weight.