Development and application of a large scale 3D roadway rockburst disaster evolution and instability simulation test system

A large-scale three-dimensional model test system concerning rockburst disaster evolution and instability mechanism simulation, applying hydraulic loading and explosive blasting to respectively simulate in-situ stress field and dynamic load, was developed independently to investigate the impact instability process of deep roadway under the combined action of dynamic and static loads. In the whole testing process, the stress field, deformation field and geoelectric field will be obtained by using the multiple monitoring means such as parallel electrical network method, static strain acquisition system, ultra-dynamic strain acquisition system, high-speed camera and acceleration sensor. The test results show that, during the process of stress redistribution, the stress level of the surrounding rock in the shallow region of the roadway deteriorates seriously, forming a certain range of high resistance areas, while the tangential stress in the deep region of the surrounding rock appears a gradually increase trend, forming a lower resistance area. All above observations indicate that the state of the shallow surrounding rock switches from elastic to plastic, while that there is a large amount of elastic energy accumulation in the deep region, which provides favorable conditions for the occurrence of rock burst. At the moment of applying the dynamic load, the superposed force of the impact dynamic load and the high static load increases sharply and exceeds the bearing capacity of the surrounding rock, causing the broken rock mass in the shallow region of the roof to be thrown into the excavation space instantaneously accompanied by the rapid release of the elastic energy accumulated in the deep region of the surrounding rock. A large number of tensile and shear cracks are observed on the two sides of the roadway and the floor, which can be attributed to the repeated action of shock stress waves. It is shown that the test system is stable and reliable and can reproduce the process of impact instability of deep roadways realistically. The research work provides a guide for performing the failure tests of roadways with different support structures under dynamic and static loads. © 2021, Science Press. All right reserved.