An apparatus for the determination of time dependent behaviour of rock under triaxial loading

Abstract

The greater attention recently being given to tunnelling and underground civil engineering works necessitates a greater understanding of the behaviour of rock materials under a wide variety of stress/time conditions. Much rock testing work has been performed, essentially on a short time basis, in which both unaxial and triaxial loading has been employed. The authors of this note suggest that, since in practical circumstances the bulk of the rock material in the neighbourhood of an excavation or beneath a foundation is in fact triaxially loaded over long periods, the information available on rock behaviour was inadequate, and that suitable apparatus for carrying out the required long term triaxial tests was not available. This note is concerned with prototype apparatus for such testing of rock materials. Information on the design and testing of the apparatus is presented. The apparatus was used in an investigation of the creep behaviour of air dried gypsum samples subjected to triaxial loading, and the authors state that throughout this work the apparatus behaved predictably, leading to the possibility of further useful developments. /TRRL/