Deformation Control Technology of Gob-Side Entry Retaining with Large Volume CFST Roadway Side Support in Top-Coal Caving Longwall and Stability Analysis: A Case Study

Considering the factors affecting surrounding rock stability of gob-side entry retaining, applicability a large-diameter, concrete-filled steel tube roadside support body in top-coal caving fully mechanized face is discussed, and new approach to retaining proposed this study. The mechanical model structure was established, critical state column–roof contact shear slip instability clarified through Prandtl foundation failure theory, deformation mechanism retained roadway analyzed numerical simulation. results indicated that range tensile stress zone extreme roof between columns are closely related spacing columns, which key factor influencing roadway. In addition, besides uncontrollable factors, interface directly area tubes roof, size properties mass. Finally, field test carried out 91–101 working panels Wang-Zhuang Coal Mine; maximum convergence floor 510 mm, section reached 12.9 m2, within reasonable range.