Experimental modelling on failure characteristics of rockburst with different properties tunnel

QI Yanjun; DONG Zhaoxing; JING Hongwen; MENG Bo; LONG Jingkui

Abstract：In order to deeply understand the mechanism of rockburst in deep tunnels,a simulation test system equipped with energy storage devices was used in the modelling experiments on four materials models (175 mm×175 mm×200 mm) with a prefabricated tunnel (Ф=50 mm).The entire process of rockburst was reproduced by adjusting the initial stress level and loadin grate.In the process of test,a high-speed camera system was operated to real-time monitoring the failure process of the tunnel and recording the data.The occurrence and mechanism of rockburst of different models were analyzed and discussed,combined with the failure characteristics.The following research findings are presented.The failure process of the models includes three forms of static failure,static and dynamic mixing failure,and dynamic failure.The three shapes show different stages and variant degrees on the time axis of the process.The mechanism of rockburst is revealed by dividing the phases of four kinds of materials.By analyzing the time and space distribution characteristics,it is found that the addition of external energy is a necessary but not sufficient condition for rockburst.The disaster process studies of the low strength of elastic-plastic mechanics rock mass,with a R＜1 impact proneness index,provide a new insights into the research on impact rockburst mechanism of the low strength and loose coal tunnel with high support strength.The viewpoint is put forward that "the surrounding rock structure" should be the object for weak (loose) rock mass.The development of elastic energy storage device and results provide a new train of thought and cognition for the study of rockburst mechanism in deep underground engineering.