Effect of strain rate on mechanical behaviour of rocks

Abstract

In recent rock mechanics studies, more attention is being focussed on the behaviour of rocks under varying straining conditions, as it is a vital factor in the design of rock structures as well as various mining operations like drilling, blasting and crushing. Many researchers have been investigating into the effects of strain rate on strength, Young's modulus, ultimate strain and also the failure behaviour of the rocks. However, conflicting results have been obtained by various investigators. An investigation, therefore, was carried out by the authors to study the effect of strain rate on mechanical behaviour of some Indian rocks. A third degree polyncmial has been found to give the best fit to the plot between ultimate strength and strain rate, and oung's modulus and strain rate of rock samples. The failure strength was found to increase wijth increase in strain rate and an abrupt increase was observed at strain rates of 101/sec and 102/sec. The Young's modulus also increased with increase in strain rate. However, the ultimate strain was found to be independent of the strain rate. © 1989 Balkema, Rotterdam.