Squeezing failure behavior of roof-coal masses in a gob-side entry driven under unstable overlying strata

This paper endeavors to reveal the squeezing failure mechanism of roof-coal masses and its correlation with the movement of the roof strata. An integrated method incorporating field instruments and numerical modeling was conducted. The borehole camera detection revealed that the development degree and scope of cracks in the roof strata on the coal pillar side are significantly larger than that on the panel rib side, and the fracture line of the main roof occurred above the coal pillar. A rigorous modeling procedure verified the borehole camera detection results and also found that the vertical and horizontal displacement of the roof-coal mass exhibited asynchronous development characteristics at various heights. Subsequently, a comprehensive control strategy was proposed to prevent the squeezing failure behavior of roof-coal masses in DUOS gob-side entry. This study provides a basis for understanding the squeezing failure behavior of roof-coal masses, and the proposed control strategy can potentially be applied in other similar mining projects.