Stability Analysis of Roof and Rib and Source Control Countermeasures of Ultrahigh Roadway in Deep Coal Mine

Abstract

Driven by the high original rock stress and engineering disturbance, the ultrahigh roadways of about 7∼8 m appear in the deep coal mine. Based on the field measured data, the stability in different zones of roof and rib is divided. From shallow to deep, the roof forms potential leakage and falling zone, metastable zone, and stable zone, and the coal rib forms potential spalling zone, crack developed zone, and transition zone. Based on the theory of transverse isotropy, the mechanical analysis model of layered roof is established, the real stress state at any point of layered roof is deduced, the roof failure criterion is constructed, and the theoretical solution of the failure depth of layered roof is obtained. The mechanical model of pillar bar of the splitting coal body in the potential spalling zone is established, and the deflection deformation expression of the pillar bar is derived. In view of the deformation and failure characteristics of the roof and rib, this paper puts forward the cooperative integrated support technology based on high-strength prestressed cables and deep-shallow hole grouting, which effectively reduce the hidden danger of roof falling and eliminate the formation of ultrahigh roadway from the source.