Abstract：The mesoscopic numerical simulation method is employed to study the anchorage mechanism of granular mixture in geotechnical engineering. 3D random distribution particle model of granular mixture is built based on random simulation technique；the form factor is used to control the surface irregularity of the granules. In addition，nonlinear contact algorithm is presented based on modified augmented Lagrangian algorithm and is employed to simulate the interaction between granule and rockbolt. The mechanical properties of granule obey Weibull probability distribution；mesoscopic damage softening model is employed to describe granule deformation and breakage. The numerical models for triaxial shear test of granular mixture and anchored granular mixture are built；triaxial shear test is carried out based on displacement loading. The numerical simulation results show the anchorage mechanism，i. e. anchorage body intimately contacts the rock particles to produce the frictional resistance，and supporting structure forms the radial resistance the anchors and their adjacent rock granules form the anchorage zone. The numerical calculation results show that anchorage can significantly increase the shear strength and integrity of granular mixture. The peak principal stress difference can increase by 37.8%–88.8%，the initial modulus can increase by 37.4%–93.2%，and the internal friction angle can increase by 13.3%–24.2%.
