K0 Measurement in a Sand Using Back Volume Change
T. Santana, M. Candeias
Soils and Rocks, São Paulo, 38(1): 3-8, January-April, 2015 | PDF
An experimental technique, using a computer controlled triaxial test to evaluate the coefficient of earth pressure at rest, K0, is presented. The method does not require the use of any radial measurement transducers and is free from any side friction effects, typical of oedometer testing. It uses commercial software (GDSlab) which applies ramps of radial stress with back volume measurement, ensuring that the diameter change remains zero. The method is applicable only to saturated specimens in drained conditions. The equipment used is briefly described, as well as the testing procedure. Results of a laboratory test, on a granular material, applying a loading-unloading-reloading condition, are presented, and the relation of K0 with OCR (overconsolidation ratio) is investigated. The experimental results are compared with empirical equations given by other publications, suggesting the adequacy of this test method to determine K0 either in normally consolidated or overconsolidated stress paths.
Submitted on April 24, 2013; Final Acceptance on August 26, 2014; Discussion open until December 31, 2015.