The assessment of rock bursting in rock engineering structures with a particular emphasis on underground openings

In recent years, the potential of rock bursting during rock excavations such as underground openings and dam foundations due to great depth or high in-situ stress environment receives great attention in Japan. Therefore, some effective monitoring and analysis methods for predicting rockburst must be developed. Various finite element methods based on conventional elasto-plasticity, energy methods and extension strain method have been developed for predicting rockburst. Among them, the finite element method based on classical elasticity-plasticity theory was found to be appropriate if the failure zones obtained in analyses are properly interpreted. Some laboratory tests were carried out on the circular openings excavated in Ryukyu limestone and Shizuoka intercalated sandstone and shale plates and multi-parameter measurements were done in order to develop some observational and monitoring techniques for predicting rockbursts. It is experimentally demonstrated that the combined utilization of AE, rock temperature and electric potential may be a quite effective in-situ monitoring tool for predicting rockburst. This technique is used to assess the response of rock mass surrounding of Shizuoka third tunnel to face advance and to check its stability against rockburst during the excavation.