|Title||Laboratory methods for determining engineering properties of overconsolidated clays|
|Publication Type||Journal Article|
|Year of Publication||1995|
|Authors||Degroot DJ, Sheahan TC|
|Journal||Transportation Research Record|
One objective of a site and soil characterization program is to determine pertinent engineering properties, including the state of stress, stress history, and basic mechanical soil properties such as consolidation and strength characteristics. This is best done in the laboratory since boundary conditions and strain rates can be controlled. Laboratory test equipment and procedures for evaluating the consolidation and stress-strain-strength properties of saturated overconsolidated (OC) clays are described. A distinction is made between the state of the art and the state of the practice with respect to equipment and test methods. An overview is given of common laboratory equipment for determining these properties. Background is provided on preconsolidation pressure mechanisms and respective stress history profile characteristics. Guidance is offered on strength parameter selection for OC clays, which includes stability class, soil behavior issues, and methods for reducing the effects of sample disturbance. General procedures are given for performing one-dimensional consolidation tests on OC clays and estimating values of preconsolidation pressure and the coefficient of earth pressure at rest. Recommendations are given on evaluating and analyzing strength data, and it is concluded that obtaining reliable engineering properties for OC clays requires a comprehensive knowledge of deposition mechanisms, soil behavior, and appropriate experimental procedures.