Finite element numerical modelling of rock bolt axial behaviour subject to different geotechnical conditions
In rock bolting systems, grout acts as a medium to transfer initiated stress from the bolt to stable rock mass, and also to transfer the in-situ stress from surrounding rock to the bolt-grout interface. In this study interaction between the mechanical characteristics of the grout and rock bolt behaviour was investigated in different confining pressure conditions. First, the uniaxial compression strength of the grouts was experimentally determined, and then pull-out tests were carried out on rock bolts encapsulated using the same grouts to quantify the bonding behaviour. Numerical models using ABAQUS explicit finite element code were then applied to further analyse the effects of mechanical properties of the grouts and the confining stress on the behaviour of the rock bolting systems. The compression of the simulated results with the experimental tests showed that the proposed FE models simulate the axial behaviour of rock bolts efficiently. The results of the parametric study indicated that grout mechanical properties and the level of confining stress affect the ultimate bearing capacity of the encapsulated rock bolts and the force-displacement behaviour. The level of damage that occurred at the specimens due to pull-out load is also significantly influenced by these factors.
Hadi Nourizadeh, Ali Mirzaghorbanali, Naj Aziz, Kevin McDougall, Behshad Shokri Jodeiri, Ali Akbar Sahebi, Amin Mottalebiyan and Shima Entezam, Finite element numerical modelling of rock bolt axial behaviour subject to different geotechnical conditions, Proceedings of the 2023 Resource Operators Conference, University of Wollongong - Mining Engineering, February 2023, 221-229.