Research progress of roadway surrounding strata rock control technologies under complex conditions

The mining of coal resources is constantly advancing to the depths,and the problems of complex geological conditions are becoming increasingly prominent. Deep rock engineering activities such as deep resource mining and underground space excavation are increasing rapidly, and the development of these engineering activities is closely related to the stability of roadway. This paper focuses on summarizing the relevant achievements in the field of coal mine roadway enclosure control under complex conditions,combining the main complex conditions faced by the current roadway surrounding rock control,and dividing the engineering geological conditions and mining technical conditions into two types of complex roadway conditions. The deformation and failure characteristics of the surrounding rock of the roadway under various complex conditions are clarified,and it is pointed out that the surrounding rock stress,surrounding rock properties and supporting structure are the three basic objects of the surrounding rock control of the roadway. Three forms of instability,namely,deterioration of the stress environment of the surrounding rock,deterioration of the nature of the surrounding rock and weakening of the performance of the support body,are clearly identified. On this basis,the instability mechanisms of mining roadway under different geological environments and spatial-temporal relationship of mining are revealed. The basic mechanism of surrounding rock control in difficult roadways at this stage is analyzed：improving the surrounding rock stress environment,improving the surrounding rock properties and strengthening the surrounding rock bearing structure. The current status quo of the stage theoretical research and technology application of the surrounding rock control technology based on pressure relief,modification,support and synergistic control in different complex conditions of the roadway was also detailed. At the same time,the typical engineering cases of seepage stability and surrounding rock control in muddy mining roadway were analyzed,revealing the mechanism of surrounding rock instability in such complex and difficult conditions of roadway,and proposing a high-strength integrated repair and control technology system with the synergy of various methods such as water drainage and pressure relief,mud rock replacement,graded grouting,high-strength sealing support structure and bottom plate structure. Finally,based on the above four aspects of research,combined with engineering practice,the future development trend of roadway enclosure control technology under complex conditions is prospected.