Shear dynamic response of jointed rock mass anchorage system under impact load

The dynamic damage of anchored joint rock masses is very likely to cause disasters in underground engineering development and energy engineering. Considering the boundary effect，the coupling effect of rock mass-binder layer-anchor rod and damage deterioration behavior，a three-dimensional calculation model of lateral impact of rock mass with anchored joints was established by using the finite element explicit dynamics method and improving the droping weight test. The shear strain accumulation and dynamic necking breakage characteristics of rock bolt breaking surface were analyzed. The impact damage evolution process and the energy evolution law of the system were revealed. The cumulative damage mechanism of impact stiffness deterioration in the bonded layer and the impact velocity evolution characteristics of the rock mass under different boundary effects were elucidated. The results show that the deformation and damage response of the rock mass with anchored joints under impact is significantly different from that under static load，and the dynamic damage of rock bolts，the accumulated damage of bond layer and the energy evolution of the system under different boundary effects of CNL and CNS are similar，but the rock mass is subjected to greater normal stress constraint and is relatively less affected by the impact because of the additional normal stress increment provided by CNS boundary conditions. The conclusions obtained have implications for revealing the dynamic failure of rock anchorage. © 2022 Editorial Office of Journal of Mining and Strata Control Engineering. All rights reserved.