Optimization of combined support in soft-rock roadway

Ground support and reinforcement technology can greatly enhance the stability of underground excavations and make the underground infrastructure safer. This paper investigates a combined support methodology aiming at increasing the stability and safety of soft-rock roadways in the Zhongguan iron mine in China via analysis of the field structure of weak surrounding rock by means of numerical modelling, orthogonal experiments, field observations and optimization of combined support parameters. A WA scheme design for the underground metal mine roadway support was constructed to study the mechanisms of large deformations of roadway surrounding rock and the influencing factors of the side displacement, roof subsidence, and plastic zone volume were quantitatively analyzed. The optimization of support parameters was carried out in combination with numerical simulations and orthogonal tests. Modelling and field WA results show that the support effect of the optimized scheme has greatly improved the roadway stability and the combined method controls much more effectively the large deformation of the broken rock mass as well as the support function of the excavation roadway. The proposed combined support method can provide a support design reference for similar projects in similar rock masses.