Model tests on anti-explosion anchoring effect of tunnels reinforced by dense bolts at arch top

The anti-explosion model test methods are adopted to study the anchoring effect of the tunnels reinforced by dense rock bolts at arch top under the explosive stress waves produced by focus charging.According to pressure temporal curves,it is proved that the test data are proper and reliable.For the purpose of the comparison of anchoring effects between the dense rock bolts at arch top and the common rock bolts,the differences of the arch vault displacement,the surface strain,the acceleration of roof and floor and the damage shape of the two underground openings are analyzed.The results show that the anchoring effect of dense bolts at arch top is not good.