ABSTRACT
Dilatancy of several materials as sandstone and several metals, has been studied experimentally in uniaxial tests, by Bauschinger [1879], (see Bell [1973] for the early studies on irreversible volume change during plastic deformation of various materials). For granular materials dilatancy was mentioned by Reynolds [1985]. The word “dilatancy” was used by both these authors. Much later on. it was Bridgman [1949] who has found that in uniaxial compression tests the volume of soapstone, marble and diabase is dilatant at high applied stresses. He has found also that at high stresses dilatancy is produced by “rapid creep”. He also suggested that irreversible compressibility is due to closing of pores, while dilatancy (called “retrograde volume change”) to the opening of pores.
