Rockholt Behaviour Under Dynamic Loading: Field Trials and Numerical Simulation

ABSTRACT: As a part of the Canadian Rockburst Research. Programme (aimed at investigating the performance of rock support under rockbursting conditions) in-situ dynamic monitoring of various types of rockbolts loaded by blasts was performed. The aim of the monitoring was to investigate and explain the interaction of the dynamic load with the rock-rockbolt system. The measured strain waves on the bolt and the dynamic movement of the rock surface were successfully simulated numerically using a one dimensional finite difference representation of the mechanical system involving the wave source, the rockmass, the mechanical rockbolt, and the anchor and head connections. The model was calibrated using field data from the blasts, and parametric studies of the influence of various system parameters on the dynamic behaviour of the rockbolt were carried out. It was found that the wave source, rockmass modulus, tensile strength, connections at the rockbolt ends, and rockbolt pre-tension all play important roles in determining the dynamic stress levels in rockbolts.