Experimental creep tests and prediction of long-term creep behavior of grouting material

Abstract

Rock reinforcement systems, such as resin-grouted rock bolts, display complex creep behavior because both grouting materials and bolts show time-dependent behavior. In this paper, only the time-dependent behavior of grouting material was investigated, in which creep tests of grouting material was conducted in triaxial compression apparatus at room temperature. The test specimens were provided from the Araldite epoxy resin used in rock reinforcement. We attempt to predict long-term creep parameter using triaxial creep tests and to define time-dependent characteristics of the bounding material. In short-term creep tests, three different axial and confining stress levels were applied in steps to each specimen. The transient creep for all the stress levels were described by power function which fit properly to time–strain curves. The maximum difference between the proposed model and experimental long-term creep strain was less than 7.1 %. It was observed that the creep rate of a grouting material specimen directly depends on the deviator of stress (i.e., σ1–σ3).