Anisotropically Consolidated Undrained Compression Test on Residual Soil

In Malaysia, the shear strength and corresponding deformation characteristics of residual soils are normally investigated by isotropically consolidated undrained (CIU) triaxial test. In the present study, anisotropically consolidated undrained compression (CAU) tests were carried out and explored in an attempt to facilitate understanding on the fundamental behaviours of a selected residual soil. A triaxial apparatus setup which was capable of performing the CAU test was first developed. Through a monotonic strain-controlled triaxial test apparatus, soil properties and stress paths could be obtained experimentally. It was confirmed that the newly fabricated triaxial apparatus could provide reasonable experimental results. As distinguished from the isotropically consolidated undrained compression (CIU) test, anisotropic stresses were induced in the stress path test. It follows that the soil responses were different between the CIU and CAU tests. The coefficient of earth pressure at rest (Ko) values as obtained in the present experiment showed a good agreement with the values estimated using equation reported by Jaky (1948)