ABSTRACT
This chapter deals with dynamic issues such as rockburst, earthquakes, and blasting, which cause dynamic loads on rock support and rock reinforcement. Rockbolts and rockanchors are commonly used as principal support members in underground and surface excavations.
In the first part, some experiments on dynamic response of point-anchored rockbolt model under impulsive load are described in order to provide some physical evidences.
The yielding rockbolts are devised to investigate absorption of shocks resulting from rockbursts These rockbolts fundamentally utilize the displacement hardening frictional resistance while the tendon itself behaves elastically or elasto-strain hardening plastically under shock loads.
The responses of rockbolts subjected to vibrations induced by turbines in an underground powerhouse were measured at several locations in relation to the assessment of the behavior of rockbolts and rock anchors during operation.
Some model experiments were carried out on the development of axial forces in rock anchors and grouted rockbolts, stabilizing the potentially unstable blocks in sidewalls of the underground openings using shaking. The experiments clearly demonstrate that the bolts and anchors used as a part of the support system may experience greater load levels than that at the time of their installation after each passage of dynamic loads.
