Quantifying the Creep Behavior in Polyester Resin and Grout

Jacobus van der Schyff

School of Mechanical and Mining Engineering, University of Queensland, Australia

Abstract: Creep of in-situ rock bolts have been apparent and problematic since their introduction in the mining environment. If enough creep is experienced, the bolt has the possibility of failure leaving the opportunity for roof instability. In an attempt to quantifying the creep behaviour in polyester resin and cement grout, laboratory testing procedures were developed. It was decided that two separate tests would provide the data needed to fulfil the scope and objectives. The tests chosen were UCS machine deformation testing and Laboratory Short Encapsulation Pull Test (LSEPT).Based on past research in the scope of the project, a methodology was developed along with measuring techniques to accurately monitor the deformation. Based on the data analysis, the displacement for each sample from the pull test suggested that water based resin deforms the most under an induced load whereas grout tends to deform the least. The long term creep test yielded a peak strain of 0.72% and 1.11% for oil and water based resin respectively. Further calculations concluded that oil based resin had the highest resistance to failure with a shear strength of 8.47 MPa, whereas water based resin yielded a shear strength of 4.51 MPa and grout had a shear strength of 5.5 MPa.

Key words: creep, polyester resin, grout, deformation, displacement, strain, shear strength