Study on anchorage performance and parameters optimization of positive wedge anchorage hole in roadway

For the bolt support of weak surrounding rock roadway，the bottleneck problem is the low force and the fast attenuation of the anchoring force,and failure of the anchor agent is the important reason and key influencing factor.The anchoring effect of the anchorage system can be improved obviously with positive wedge anchorage hole.But due to the small anchorage range of the single end reaming，the anchorage system can be easily affected to failure under the mining environment.This paper studies the combination schemes of the positive wedge and the ordinary cylindrical anchorage hole under different anchoring types.Research results show that in the case of end bolt anchorage effect with the bottom reaming of theholeis best,in the case of long bolt and all bolt，bolt anchorage force is improved by reaming the bottom of the hole，but not significantly.On the basis of fully consideration of multiple factors such as the constructiontechnology and economic security，1∶2 is the best length ratio of the reaming and the anchoring.As the lengthand the radius of the reaming hole become larger，the stability of the anchorage system and anchoring ability becomes stronger.But the radius of the reaming hole depends on the construction machinery，construction technology and conditions of surrounding rock，and should be determined according to the field situation.