JRMGE / Vol 13 / Issue 1
Principles and methods of rock support for rockburst control
Charlie Chunlin Li
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Norwegian University of Science and Technology (NTNU), Trondheim, Norway
2021, 13(1): 46-59. doi:10.1016/j.jrmge.2020.11.001
Received: 2020-10-12 / Revised: 2020-11-06 / Accepted: 2020-11-11 / Available online: 2021-02-15
2021, 13(1): 46-59.
doi:10.1016/j.jrmge.2020.11.001
Received: 2020-10-12
Revised: 2020-11-06
Accepted: 2020-11-11
Available online: 2021-02-15
This paper presents the principles of rock support for rockburst control and three rockburst support systems used in deep metal mines. Before the principles of rock support are presented, rock fracture related to strain burst is first discussed with the help of photos taken on site, and the energy sources and transformations during bursting are illustrated through conceptual models. Surface parallel extension fracture usually occurs in the ejected and surrounding rocks in a strain burst event, while the ejected rock in a fault-slip rockburst is often already pre-fractured before the event. There must be excessive release energy available for rock ejection. The excessive release energy comes from both the ejected rock itself and the surrounding rock. To prevent rock ejection in a rockburst, the support system must be able to dissipate the excessive release energy. All support devices in a support system for rockburst control must be able to dissipate energy, be firmly linked, and be compatible in deformability. A support system for rockburst control comprises surface-retaining devices and yield rockbolts as well as yield cablebolts when needed. Laying mesh on the top of shotcrete liner is a good practice to enhance the surfaceretaining capacity of the support system. Energy-absorbing yield rockbolts dissipate energy either by stretching of the bolt shank or by sliding of the inner anchor in the borehole. Mesh, mesh strap and shotcrete are the surface-retaining devices widely used in the current rock support systems. The three types of rock support used for rockburst control at present are soft support system using Split Set bolts, hybrid support system using rebar and two-point anchored yield bolts, and entirely yieldable support system using strong yield bolts.
Keywords: Rock support, Rockburst, Rockbolt, Yield rockbolt, Mesh, Shotcrete
Article Data
Author(s) Information
Prof. Charlie Chunlin Li
charlie.c.li@ntnu.no
Charlie Chunlin Li is a professor of rock mechanics for civil and mining engineering in the Norwegian University of Science and Technology (NTNU) in Norway. He is in charge of the teaching and research program in rock mechanics in the university. Li obtained his BSc and MSc degrees in Central South Institute of Mining and Metallurgy, China, in 1981 and 1984, respectively, and PhD degree in Lulea University of Technology (LUT), Sweden, in 1993. His work experience includes research associate and associate professor in LUT, ground control engineer in Boliden Mineral Ltd., Sweden, chief technical officer in Dynamic Rock Support AS, Norway, and professor in NTNU. His expertise is in stability analyses of underground space and ground control. In the last two decades, his research interest has been focused on the performance of rockbolts and rock support in difficult rock conditions. He invented the D-bolt that has been worldwide used for rockburst control in deep underground mines. He published a book entitled Rockbolting – Principles and Applications. He is a member of the Norwegian Academy of Technological Sciences (NTVA). He was the International Society for Rock Mechanics and Rock Engineering (ISRM) Vice-President for Europe 2015–2019.