Failure mechanism and control of deep gob-side entry

Gob-side entry (GSE) is defined as caving that is developed along the gob with a yield pillar. Compared to other entry layouts, GSE has many advantages, such as the advantageous stress environment, high recovery rate, and prevention of coal bumps. Recently, many Chinese coal mines have reached deep mining depths. As a result of the high stress in deep mining conditions, severe bulk and dilatant deformation has occurred in deep GSE (DGSE). The direct problems in this situation, such as interruptions to production, increasing rehabilitation cost, and high labor consumption, affect the safety and mining efficiency of deep coal seams. In this paper, based on analysis of the deformation characteristics of a typical DGSE, numerical modeling was used to study the causes and mechanism of DGSE failure. In addition, a series of strategies are proposed for DGSE deformation control. The case study presented indicates that the proposed control strategies can prevent severe deformation of the DGSE. Thus, the results of this research can be used as a reference for DGSE control in other deep mining settings.

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