Underground rock support has experienced an evolution from sporadic bolting by mechanical bolts and steel sets to systematic bolting with fully grouted bolts, meshing, dry-sprayed concrete, wet-sprayed plain concrete, fiber reinforced sprayed concrete and sprayed concrete arches in the past more than 50 years. The reasons for the evolution will be explored in the speech. The current ground support methodologies in both civil and mining engineering are presented and summarized in a general ground support model. The focuses of ground support are different in civil tunnels and mines. In civil tunnels, the dominant support elements are sprayed concrete liners and arches (steel or concrete) that are setup externally, whiles in mines internal elements like rockbolts and cablebolts play major roles in stabilization of the rock mass. In deep mines, rockburst is a serious threat to the mining operation. Rockburst support systems have been introduced in many deep burst-prone mines. Various yielding support elements are used in the systems and various and debatable support philosophies guide the design of rockburst support at present. It is different opinions on how the support elements are loaded when rockburst occurs, whether the support design is based on deformation or energy dissipation or both, etc. The debatable issues are presented and discussed in the speech. The characteristics of individual yielding support elements will be also presented.

Biography

Dr. Charlie Li is a professor in rock mechanics for mining and civil engineering at the Norwegian University of Science and Technology (NTNU), Norway. His expertise is in stability assessment of underground spaces and ground control. He worked as a ground control engineer in a mine in Sweden for more than four years before his academic career at NTNU. His interests are rockbolting technology, ground support, dynamic ground support and rockburst. He published a book entitled “Rockbolting – Principles and Applications” in 2017. Professor Li is a member of the Norwegian Academy of Technological Sciences. He was the ISRM Vice President for Europe 2015-2019.