A Two-Fold Empirical Approach for Estimating the Preconsolidation Stress in Clay Deposits

Abstract

The conventional method for determining preconsolidation stress of clay is via one-dimensional consolidation tests on undisturbed samples but a first-order approximate value can be estimated from simple empirical models that relate preconsolidation stress to easily measured soil properties, such as natural water content, liquid limit, plasticity index, etc. In this paper, a two-fold simple empirical model for predicting preconsolidation stress that bifurcates at an overconsolidation ratio (OCR) of 3 is developed. Two independent data sets which consist of about 2000 samples of fine-grained soils are used as model-building and model-validation data sets. The results of applying the new and existing simple empirical models to validation data set indicate that (1) the proposed model provides quite acceptable estimates for soils with different stress histories and sensitivities, (2) the predictive ability of the new model is quite superior to existing models, and (3) the performance of prior existing models can be classified as unacceptable.