Coordination mechanism of internal strong active support,soft structure pressure relief and anti-punching of roadway

In order to explore the stability control technology of deep rockburst roadway,and to solve the contradiction between the support and the pressure relief impact on the roadway,taking the 21170 roadway of Changcun Coal Mine in Yima as an example,according to the strong-soft-strong structural model of roadway in the impact area,the theoretical analysis,numerical simulation and field test are used to analyze the energy absorption characteristics of strong-softstrong structure,internal strong structure energy damage criterion and soft structure energy absorption effect. Based on the theory of the mechanical characteristics of the fractured zone of the borehole,the influencing factors of the pressure relief zone of the soft structure of repeated drilling are deduced. The repeated cracking radius is related to the drilling radius,initial stress,internal friction angle,elastic modulus,modulus reduction,peak strength,and drilling radius correction factor. Through the numerical simulation,the failure law of the strength of the surrounding rock of the roadway and the structural integrity control of the supporting body and the stress and displacement of the surrounding coal and rock body are analyzed by the internal steel pipe borehole protection technology. The strengthening technology of active support for internal strong structure and the method of repeated drilling caused by internal steel pipe in the pressure relief and control structure are studied. Through the monitoring of micro-seismic energy,the energy absorption effect of soft structure is verified. The internal steel pipe borehole protection technology can repeatedly drill the soft structure under protecting the internal strong structure from damage,not only prevents the crack expansion in the loose circle of the internal strong structure,but also prevents the overall instability of the supporting layer of the roadway. The engineering practice show that the anchor cable active support+hydraulic lifting shed reduction span strong support+soft structure energy absorption technology form an integrated technology of internal strong support structure and external soft pressure relief structure. The micro-seismic monitoring shows that the vibration energy is reduced by 50% ,the displacement of the two sides of the roadway and the roof subsidence are significantly smaller,which effectively maintains the stability of the surrounding rock of the roadway and ensures the smooth and safe mining of the working face. The research results provide a reference for similar roadway anti-shock and support in the impact area.