Mechanical Model and Control Technology of Roadside Gangues in Gob-Side Entry Retaining by Roof Cutting

Abstract

Gob-side entry retaining by roof cutting (GERRC) is a new technique regarding a non-pillar mining method based on the “cutting cantilever beam theory” proposed in recent years. In this technology, the composition, formation mechanism, load transfer mode and stability mechanism of roadways are quite different from those of traditional coal mining methods. Based on the technical principle of the GERRC, the formation mechanism of the sidewall composed by collapsed gangues is clarified. Also, on basis of the observation of engineering site, the movement characteristics of the gangues in goaf are analyzed, and the movement processes are mainly divided into two stages, i.e. the rapid collapse stage and the slow compaction stage. Then, the interaction between the gangues and retaining structures in different movement stages is revealed. Meanwhile, a mechanical model of the roadside gangues was established, and the mechanical characteristics of the retaining structures were analyzed. Besides, a control concept, considering both dynamic and static pressure in the lateral direction and making it extensible to release pressure in the axial direction, was put forward to support the gangues in goaf based on the interaction characteristics of the gangues and the retaining structures. At last, three different retaining structures for the gangues were proposed in view of different mining heights, and the roadside gangues control system was established, which has been proved to be of good practicality in the engineering site. The research results can provide technical guidances for the control of roadside gangues in the GERRC and accelerate the process of popularization and application of the GERRC, which is of positive significance.