CONSTRUCTION PORE PRESSURES IN CLAY FOUNDATIONS UNDER EMBANKMENTS .2. GENERALIZED BEHAVIOR

The pore pressures observed under 30 embankments on clays of widely varying geological origin and geographical location are analyzed to confirm the validity of the concepts developed from the Saint-Alban case history presented in Part I of this paper. It is shown that a significant consolidation does occur in all but one case in the early stages of embankment construction. As a result the vertical effective stress increases rapidly to a value equal to P//c. For further loading on the then normally consolidated clay the pore pressure coefficient assumes a value of 1. 0. The observed behavior is interpreted by means of the YLIGHT model of clay behavior proposed by F. Tavenas and S. Leroueil and is shown to apply directly to all clays with an overconsolidation ratio less than 2. 5, and with some modifications to heavily overconsolidated clays. The consequences of this behavior on the analysis of stability and settlements of embankments are presented. Refs.