Research on collaborative control technology of surrounding rock deformation by unloading-injection-anchoring in large roadway group in soft coal seam

In order to prevent and control the rheological deformation of the main roadway group in soft coal seam under asymmetric stress, a new collaborative control technology of surrounding rock deformation by unloading-injection -anchoring in large roadway group in soft coal seam was proposed based on the research background of the sustained deformation caused by mining in the main roadway group of the Sanpan Distric of Zhaozhuang Coal Industry. By carrying out numerical simulation and analysis of roof structure of wide coal pillar protection roadway, the correlation between stress state of large roadway group and goaf roof was revealed, and the mechanism of blasting fissure belt in blocking stress transfer was clarified. The theoretical basis of blasting precracking of mining roadway roof and multi-layer precracking of main roadway in disk area was defined, and deep-shallow hole combined pressure relief technology and inner outer ring collaborative reinforcement technology with anchoring grouting as the core have been established. The parameters of blasting precracking and grouting were determined by theoretical deduction and field test. The engineering practice shows that the blastingg process has achieved sufficient precracking of the hard roof, and the anchoring-grouting process has improved the integrity of the surrounding rock of the roadway. After the mining of the 3312 working face, the roof and floor and two sides of the main roadway group are moved in a small amount, and the purpose of collaborative control of surrounding rock deformation by unloading-injection -anchoring was achieved.