Passive Earth Pressure of Normally and Overconsolidated Cohesionless Soil in Terms of Critical-State Soil Mechanics Parameters

Abstract

Earth pressure theories occupy a paramount position in the field of geotechnical engineering. Passive earth pressure plays an important role in the design of retaining walls and anchors. Furthermore, it provides the resisting force used in modeling soil–structure interaction problems. In the literature, numerous reports can be found dealing with the passive earth pressure for cohesionless soil. The majority of these reports have used the Mohr-Coulomb criteria as the constitutive law governing the relationship between the passive earth pressures and the angles of shearing resistance of sand. Accordingly, the results obtained have displayed a wide range of discrepancies in the values of the coefficient of passive earth pressure, especially for the case of overconsolidated sand. This paper presents a numerical model for a retaining wall translating horizontally into a mass of sand and accordingly subjected to passive earth pressure. The model utilizes the finite-element technique, the constitutive law of the modified Cam-clay model, and the critical-state soil mechanics (CSSM) concept. This model is capable of incorporating the effect of soil deformation and the stress history of the sand into the values of the passive earth pressure, which were ignored in previous models. After validating the numerical model with the available experimental data for normally consolidated and overconsolidated sands, the model was used to generate data for a wide range of parameters. The results were used to develop design theories capable of predicting the passive earth pressure for normally consolidated and overconsolidated sands as function of the CSSM parameters. Furthermore, a procedure is presented to evaluate these parameters from the results of triaxial tests.