Evaluation of Pre-Consolidation Stress Determination Methods

Pre-consolidation pressure provides valuable information about soil behavior and, specifically, settlement under an induced load. Soil is expected to have less settlement before its pre-consolidation pressure and much more settlement after that point. The pre-consolidation pressure and the compressibility of the soil can be determined from the results of a one dimensional consolidation test. Different methods have been developed to obtain the accurate pre-consolidation pressure from one dimensional consolidation test data. This paper presents and discusses the results of the one-dimensional consolidation test data from an extensive testing program. The test specimens used were obtained from multiple borehole locations and were extracted using Shelby tube samplers. The focus of this paper is the comparison of three pre-consolidation stress determination techniques, which were performed on each specimen of the large sample pool. The methods used were the Casagrande method, strain-energy method, and intersecting tangent method. The implementation of these methods will be evaluated. In addition, the subjectivity of each method will be addressed. The final results of the techniques will then be compared and contrasted.