Roof collapse mechanism and key control technology and equipment for mining-affected in coal mines

In response to the challenges posed by complex surrounding rock conditions, high mining intensity, and significant strata pressure in coal mine mining-induced roadways—which often result in dynamic pressure phenomena such as roof collapse and large deformations—the mechanism of roof collapse has been systematically investigated. The direct causes and the mechanical essence underlying roof failures in such environments are revealed. Scenario-based models of roadway roof disasters have been developed, encompassing fractured hazardous rock falls, loose rock mass collapses, weakly bonded composite roof failures, and butterfly leaf-type roof collapses in severely deformed roadways. These models clarify two primary categories of roof collapse: inherent defect type and mining-induced type. Guided by these findings, a suite of key technologies and equipment—each with independent intellectual property rights—has been designed to control roof collapse throughout the entire service cycle of coal mine roadways. These include a grading and positioning investigation method for roof disaster hazards, intelligent perception technology for roadway surrounding rock conditions and an intelligent decision-making system for support design, and a comprehensive hydraulic temporary support system for excavation, equipped with clustered frame-mounted bolt drilling rigs. Additionally, a novel “three-machine” coordination model has been developed for excavation working faces, integrating a boom-type roadheader, a comprehensive excavation shield support, and a frame-mounted rail-bound bolt drilling rig. Further advancements include irregular variable-aperture drilling for enhanced anchorage, large-deformation impact-resistant tough anchor cables, and foldable non-redundant advance supports. Their research and development background, core innovations, and successful applications are further detailed. Collectively, these innovations address key issues such as the mechanisms of roof collapse under complex geological conditions, the positioning and early warning of potential roof hazards, and the implementation of full-cycle roof safety support. The resulting system enables visual and intelligent analysis of roof collapse risks and differentiated support design for various roadway conditions. This work holds substantial significance and broad application prospects for eliminating roof collapse hazards at their source, enhancing coal mine disaster prevention and control capabilities in China, and safeguarding national energy security.