Dynamic and static analysis of a kind of novel J energy-releasing bolts

Abstract

Energy-absorbing rockbolt is now recognized as an important support element in deep mines around the world. A novel kind of energy-absorbing bolt called J-bolt was developed, which consists of anchoring (damping) module, deformation module, blending module and thread segment. The static pulling loading model and dynamic impact constitutive model of J-bolt were established. The experiment results show: (1) the static pulling load is greater than 190 kN; (2) under multiple dynamic impact loading condition, the peak load of J-bolt exceeds 250 kN each time. Under the given initial dynamic impact loading condition, with the increasing of damping ratio, the oscillation amplitude of J-bolt attenuates quickly along the bolt axial impact direction. The greater the damping effect of J-bolt, the more quickly releasing of the dynamic impact energy. The absorbed energy of J-bolt exceeds 19.3 kJ under each dynamic impact, the accumulated energy absorbing capacity reaches 46.5 kJ. Due to the objective existence of joints in rock mass, the bolted rock mass can generate dilatation and tensile failure in the joints surface of rock mass under dynamic impact condition, but the energy-absorbing support system will keep surfaces of tunnels (stopes) stable, which can effectively absorb the kinetic energy induced by dynamic hazards.

Keywords

• deep mining
• j energy-absorbing bolt
• rock burst
• static pull test
• dynamic impact test