A numerical simulation approach of energy-absorbing anchor bolts for rock engineering

Energy-absorbing anchor bolts are widely used in geotechnical engineering, but there is no effective numerical simulation approach for evaluating them at the engineering application level. According to typical laboratory test results, the energy absorption criterion (F ≥ Fy) and breakage criterion (δ ≥ δf) are defined. The constant resistance energy absorption mechanical model and the increasing resistance energy absorption mechanical model are built. Based on the above two basic models, five mechanical models of energy-absorbing bolts, namely, constant resistance and large-deformation anchor bolts (CRLD), increasing resistance and large-deformation anchor bolts (IRLD), Y-bolts, cold drawn constant resistance and large-deformation anchor bolts (CCLD) and D-bolts, are developed. Based on the modification of cable elements in FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions), the numerical models of the above five kinds of energy-absorbing bolts are established, and the implementation process and specific capabilities of these models are introduced in detail. Numerical tensile tests are carried out, and the results show that the program is effective in executing the above mechanical models. Numerical simulations of deep coal mine roadways supported with different energy-absorbing bolts and absorbing parameters were carried out. The results show that the effectiveness and sensitivity of the mechanical model of energy-absorbing bolts and conventional bolts are realized by this method. The breaking effect of conventional bolt support and the yield support effect of energy-absorbing bolts in the roadway can also be better simulated.