Roof control mechanism and partition compensation support technology of gob-side entry formed by N00 mining method in thin coal seam

Abstract

To achieve scientific and accurate support for the roadway roof in the N00 mining method for thin coal seams, the roof-cutting self-forming roadway is divided into two stages: the advanced chamber stage (Stage I) and the roof collapse and roadway formation stage (Stage II), considering its technological process and the characteristics of roof deformation. Using the Hoek-Brown nonlinearity rock mass strength failure criterion, we derive the formula for the required pre-tension force of anchor bolts/cables at different stages of the roof. Additionally, a design approach is proposed for determining the necessary pretension force and length of anchor bolts and cables. Moreover, the supporting mechanism of anchor bolts/cables and the impact of different supporting combinations on the stress distribution of the surrounding rock are obtained through numerical simulations, elucidating the influence of key parameters in the design of anchor bolts/cables on roof stability. Finally, the partition compensation support technology (PCST) is introduced, and the design principles for anchor bolts and cables on the roof are established. Furthermore, this innovative support technology is implemented at Xintai Coal Mine, yielding favorable results in field applications.

Keywords

N00 mining method / gob-side entry / upper bound method / roadway support design / numerical simulation

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