Entry Deformation Law in the Full Life Cycle Under Entry Retaining with Roof Cutting

Abstract

In roof cutting pressure releasing gob-side entry retaining (RCPRGER) technology, the full life cycle of the retained entry includes two main parts: the entry retaining and retained entry reuse. The existing studies all focus on the process of entry retaining, while the studies of the whole life cycle and reuse process are relatively deficient. To compensate for the deficiency in the existing research and explore the deformation law of the entry in the whole life cycle under entry retaining with roof cutting, this paper takes the 8304 and 8305 working faces of the Tashan Coal Mine as an example, and the entry deformation evolution in the retaining and reuse processes is studied. First, this paper summarizes the technological process of RCPRGER and reuse and then deduces the stress evolution process of entry surrounding rocks, specifically including the analysis of the roof cutting short beam structure model. Subsequently, the monitoring schemes of the entry deformation and mine pressure in the working face within the retaining and reuse processes are proposed. Finally, through the practical examples of test working faces, it is found that the two entry sides move symmetrically between the upper and lower parts. The main deformation in the early stage of the entry retaining is the displacement of the gangue wall, and the main deformation in the later stage and reuse stage is the displacement of the coal wall. The roof and floor move asymmetrically between the left and right parts, the deformation of the roof cutting side is larger at each stage, and the roof subsidence is the main source of deformation.