Distribution experimental des contraintes le long d'ancrages scenes dans un massif rocheux soumis a des charges de tensionnement

CIM Bulletin, Vol. 84, No. 951, 1991

B. Benmokrane et G. Ballivy, Universite de Sherbrooke, Sherbrooke, Quebec

The load transfer mechanism and the debonding process along grouted rock anchor, subjected to tention loads, can be examined through the instrumentation of the anchor with the aid of strain gauges. In this context, the results of a full-scale site investigation including classical pull out tests and creep tests are presented in this paper. These tests were performed on instrumented bars which were cement grouted in a competent rock mass. Results presented in this paper concern, among others, shear stress profiles along the grouted anchors which were determined from strain values obtained from the strain gauges. These results have been used to: (1) predict the load level corresponding to initial debonding of the grout; (2) study the effect of debonding on shear stress distribution along the anchor; and (3) characterize the creep behaviour of the bar anchor/cement grout system.
Keywords: Rock mechanics, Grouting, Anchors, Shear stress.