LABORATORY EVALUATION OF HORIZONTAL STRESS IN OVERCONSOLIDATED SANDS

This paper describes a method for the determination of in situ horizon tal stresses of heavily overconsolidated sands using a stress-path tri axial apparatus. This method was proposed by Garga and Khan (1991), wh o applied it to overconsolidated clays. The proposed method is based o n the concept that if the radial stress exceeds the in situ horizontal stress while maintaining the axial stress constant and equal to the i n situ vertical effective stress, only then will the specimen experien ce significant axial strain. In this investigation, the above method w as applied to specimens of known stress histories of overconsolidated sand. Simulation of complex stress histories was carried out by subjec ting the soil specimens to one and two cycles of loading in drained co nditions (rate of loading or unloading: 0.05 kPa/min). It was found th at the proposed method replicated the simulated in situ horizontal str ess exactly. The technique is capable of estimating K-o irrespective o f the previously imposed stress history.