Particle size effects in granular soils under true triaxial conditions

The size effect theory was proposed by Frossard and co-workers for evaluating the shear strength of rockfill material. However, this theory has not been validated in a general stress path, in which the intermediate principal stress may be different from the minor principal stress. A series of true triaxial compression tests on rockfill material A (RFM-A, a small-sized particle) and rockfill material B (RFM-B, a larger-sized particle) were carried out to validate the size effect theory in the general stress state. It was found that the predictions by the size effect theory, based on the material constants from the strength data of RFM-A, were in good agreement with the strength data of RFM-B.