Experimental Study on Strain Rockburst Characteristics of Metamorphic Sandstone in Deep Buried Tunnel

Rock burst is a geological hazard that frequently occurs in deep underground engineering and has become a significant problem during the construction of deeply buried tunnels. Using the Gaoloushan Tunnel as the research background, we utilized a self-developed experimental system for simulating deep rock burst processes to conduct strain rock burst experiments. These experiments were conducted under varying stress paths to replicate both hysteresis and instantaneous rock burst phenomena. The experiment involved analyzing the infrared thermal imaging and acoustic emission characteristics of the entire strain rock burst process. The results indicate that: The rock burst sample experiences a quiet period, crack propagation period, particle ejection period, and rock burst occurrence period from the initial loading to the point of rock burst failure under various stress paths. The temperature in the area of failure rapidly increases during rock burst, and particle ejection often accompanies the highest temperature. In addition, energy is generated throughout the loading process until the sample ultimately fails. The amplitude and peak frequency of acoustic emission are comparable between delayed and instantaneous rockburst samples, and the cumulative energy of acoustic emission is relatively high.