a School of Civil Engineering, Southeast University, Nanjing, 211189, China
b Oulu Mining School, University of Oulu, Oulu, 90570, Finland
2024, 16(12): 4909-4924. doi:10.1016/j.jrmge.2024.02.029
Received: 2023-09-12 / Revised: 2024-01-29 / Accepted: 2024-02-29 / Available online: 2024-05-29
2024, 16(12): 4909-4924.
doi:10.1016/j.jrmge.2024.02.029
Received: 2023-09-12
Revised: 2024-01-29
Accepted: 2024-02-29
Available online: 2024-05-29
This study investigated the sidewall rockburst characteristics of highly stressed circular tunnel subjected to impact loads resulting from rock blasting or other mining-related dynamic disturbances, aiming at exploring the influence of vertical prestress and dynamic load on sidewall rockburst. Using a biaxial Hopkinson pressure bar (BHPB) system, we studied the sidewall rockburst of a circular tunnel by applying various prestresses (horizontal and vertical static stresses) to a sand prefabricated circular hole specimen, followed by impact loads. The real-time process and strain field of the sidewall rockburst around the specimen were tracked by the high-speed camera and digital image correlation (DIC). The tests reveal that the sidewall rockburst process can be summarized as: calm stage, slab buckling and spalling stage, rock slabs ejection stage, and V-shaped notch formation stage. Furthermore, the sidewall rockbursts exhibit typical dynamic tensile failure. The mechanism of sidewall rockburst under the coupled static-impact loads was summarized, i.e. the static prestress determines the initial stress and strain distribution, and the vertical prestress influences the affected range and strain values of the strain concentration zone; the impact load disrupts the original static stress equilibrium, inducing alterations in the stress and strain of the surrounding rock and triggering sidewall rockburst.
Keywords: Rockburst, Spalling, Vertical prestress, Circular tunnel, Impact load, Biaxial Hopkinson pressure bar
Fengqiang Gong obtained his BSc and MSc degrees from Central South University (CSU), China, and PhD degree from CSU and Swiss Federal Institute of Technology in Lausanne (EPFL). He is a professor in the School of Civil Engineering at Southeast University (SEU), a part-time professor at Hunan University of Science and Technology, and a guest professor at International Joint Research Laboratory of Henan Province for Underground Space Development and Disaster Prevention, China. His current research interests include failure mechanism of rockburst (coal burst) and spalling, rock energy storage law and application, rock dynamics, strength-weakening mechanism of deep rock, and damage constitutive model. He is a member of the International Society for Rock Mechanics and Rock Engineering (ISRM) and International Association for Engineering Geology and the Environment (IAEG), the Vice Chairman of Professional Committee of Rock Breaking Engineering and Deputy Secretary General of Professional Committee of Rock Dynamics of Chinese Society for Rock Mechanics and Engineering (CSRME). He was invited to give a plenary lecture at the 11th “Tjongkie Tan Lecture“ – the highest academic forum of rock mechanics and Engineering in China, and also won the “Tjongkie Tan Award” for 2020 outstanding paper in Chinese Journal of Rock Mechanics and Engineering in 2021. He was selected as an Elsevier 2020, 2021 Most Cited Chinese Researchers and the world's top 2% scientists (single year impact) from 2020 to 2022 by Stanford University. He is a member of the editorial boards of Chinese Journal of Rock Mechanics and Engineering, Journal of Engineering Geology and Journal of Mining and Strata Control Engineering.