Methods for evaluating overconsolidation ratio from piezocone sounding results

Methods for estimating the overconsolidation ratio (OCR) of soil deposits from piezocone sounding results have been investigated. Three existing methods have been briefly reviewed and a new method has been proposed. The proposed method can be applied to both normally consolidated/overconsolidated and underconsolidated deposits. Furthermore, existing methods have been modified so that they can be applied to underconsolidated deposits. Then, all the methods have been applied to 12 case histories collected from 6 different countries. The estimated values of OCR have been compared with the measured data. It has been shown that if the parameters (soil properties and empirical parameters) can be determined appropriately, then all the methods can achieve a reasonable prediction. It has also been shown that the proposed method exhibits a relatively better performance and results in less scattered data than the other methods.