Volume 35, Issue 1 (January 2012)
A Cost Effective Triaxial Test Method for Unsaturated Soils
This paper describes a test method to measure the shear strength of unsaturated soils using standard triaxial equipment with minor, low-cost modifications. The method is based on using the axis translation technique in a standard triaxial testing apparatus with a base pedestal slightly modified to accommodate a high-air-entry ceramic disk. The testing apparatus and procedure are described. The aim of the proposed test setup was to limit the modifications of the standard triaxial setup within a reasonable budget to make the method accessible and attractive to researchers and practitioners that may otherwise not be able to afford the testing devices commonly used in the field of unsaturated soil mechanics. Thus, the paper discusses the effectiveness of the proposed test method, and also discusses the potential limitations that may exist due to some of the simplifications used in this methodology. The proposed methodology was used to evaluate the shear strength of residual soils at the Auburn National Geotechnical Experimentation Site. The shear strength parameters obtained for the Auburn unsaturated soils were compared to previous tests conducted in similar soils and proved to be reasonably accurate.