Mechanism of high stress roadway floor rock burst and multi-level prevention and control technology

For the instability and damage caused by the rock burst of high stress roadway in deep areas, which often occur through the bottom plate as a breakthrough point, the 75.00 m wide coal pillar in the 401102 working face of Mengcun Coal Mine in Binchang Mining Area, Shaanxi Province, was taking as the engineering background. The mechanism of disaster caused by the rockburst of the wide coal pillar in the openair was analyzed, and the failure mode of the roadway bottom plate was analyzed using numerical simulation technology. A full structure model of force source bearing of the roadway surrounding rock was established, and the mechanism of bottom plate rock burst manifestation was further studied. The in situ shock wave CT technology was used to detect the distribution of the rock burst hazard index of the 401102 working face. Finally, a multi-level full structure prevention and control method for high stress roadway was proposed by different steps and sources. The results show that the disaster mechanism caused by the rock burst of a wide coal pillar in open air is as follows: the wide coal pillar provides a load bearing position, the self-weight stress provides the foundation static load, the rear and lateral overhang of the working face provide incremental static load, and its sudden rupture provides incremental dynamic load. Multiple factors lead to the bearing stress of the wide coal pillar exceeding the critical value of the rock burst, and then the rock burst ground pressure occurs. The bottom plate of the roadway is the main bearing area for the dynamic and static loads of coal rock system, and it is also the main manifestation area of rock burst failure. It presents a progressive failure mode, manifested as asymmetric failure. Static load is a necessary condition for the occurrence of rockburst ground pressure. Using in-situ seismic CT detection technology, it was found that there is a static load concentration zone in the 401102 working face, which has a moderate rock burst risk overall. To prevent the initiation of rock burst, a multi-level and full structure rock burst prevention technology of "reducing mining disturbance, compensating mining disturbance, strengthening roadway support" has been proposed, and a reasonable rock burst prevention mining plan has been carried out. The research results have certain reference significance for the prevention and control of rock burst.