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To solve the problem of large deformation of roadway with deep composite roof, based on the material roadway of 3205 working face in Xin’an Coal Mine as the engineering background, the deformation and failure characteristics of roadway with composite roof and its influencing factors were analyzed by combining field analysis and UDEC numerical simulation. Based on the principle of thick layer anchoring of roadway roof, a technical scheme of graded continuous cross-boundary anchoring was proposed. The feasibility of the new scheme is verified by field monitoring and simulation results. The results show that the initial support strength is very important for roadway maintenance. The optimized support scheme can effectively control the deformation of roadway surrounding rock, and the deformation of roof and two sides is reduced by 64% and 63% respectively. The maximumcrack depth decreased from 9.56 m to 3.26 m. The new support scheme constructs the anchor rock beam structure with thick and stable roof, which can maintain the long-term stable bearing capacity of the roadway.

In order to solve the problem of asymmetric large deformation control of steep coal seam roadway, taking steep coal-rock interbedded roadway in Zhaojiaba Mine as the engineering background, the asymmetric deformation mechanism of steep coal seam roadway was discussed by using the research methods of field observation, theoretical analysis and numerical simulation, and the cross-border bolt-grouting differential support technology was proposed based on the cross-border support principle. The occurrence of steep coal strata leads to the unsymmetrical stress distribution in surrounding rock of roadway, which leads to the shear slip deformation of coal and rock at the top of arc, while the deformation at the top of straight inclined coal is relatively small. Different anchorage lengths and bolting-grouting methods are used to establish the differentiated cross-border support forms on both sides, and the equivalent thick anchor bearing structure of surrounding rock of roadway is constructed. The simulation shows that the surrounding rock stress is optimized, the deformation of roadway is significantly reduced, the settlement of arc roofis reduced by 39.0%, and the convergence of the side wall is reduced by 41.6%. Field industrial verification shows that the maximum crack depth of arc roof is generally reduced from 3.88 m to 1.50 m, which is 61.3% lower, the crack development depth of straight inclined roof is reduced by 47.6%, and the surrounding rock control effect is improved.

This study delves into the influence of inherent minerals within coal gangue (CG) on the preparation and performance of coal gangue /polyethylene (CG/PE) composites, focusing on the role of SiO2 in interfacial compatibility. A systematic examination unveils the consequences of varying SiO2 content on physical, mechanical, thermal, and microstructural attributes of the composites. SiO2 incorporation significantly improves physical properties, boosting density and hardness but impacting tensile strength negatively. It enhances bending strength and modulus while diminishing tensile strength. Judicious SiO2 addition enhances thermal stability, but excess SiO2 may compromise thermal decomposition. Microstructural analysis, including SEM and FTIR, elucidates SiO2‐PE interactions, primarily through physical entanglement. SiO2 introduction promotes more ordered PE molecular chain arrangements, elevating composite crystallinity. In summary, this study provides in‐depth insights into SiO2's mechanistic impact on CG/PE composite properties, laying a robust foundation for designing environmentally friendly composites. These findings hold promise for advancing sustainable materials science and engineering. Future research may explore SiO2 optimization for specific applications and synergistic effects with other fillers in composites. Highlights: SiO2 greatly improves the properties of CG/PE composites with detailed exploration.Reveals the specific SiO2‐PE interaction mechanism for a better comprehension.Performs structural analysis via XRD with valuable findings presented.Promotes pioneering advancements in eco‐friendly materials with broad significance. [ABSTRACT FROM AUTHOR]