A Novel True Triaxial Apparatus for Simulating Strain Bursts Under High Stress

This paper introduces a new high-pressure servo true triaxial rockburst experimental apparatus that can realize multi-face rapid unloading in the horizontal direction. The apparatus is used to simulate different types of strain burst phenomena in deep underground engineering, such as those at roadways, roadway intersections, and pillars with three and four free faces. In the research and development process, apparatus technologies were included to overcome five key challenges: rapid unloading under high pressure, loading gap removal fixture, three-way loading alignment, symmetrical loading, and system stability after unloading. The apparatus is used to carry out multi-face unloading strain burst experiments and can fully satisfy the experimental requirements. The entire strain burst process is recorded using a high-speed camera. The apparatus can provide experimental support for strain burst mechanism research and an experimental basis for different types of strain burst research.