Development Law of Water-Conducting Fracture Zone in the Fully Mechanized Caving Face of Gob-Side Entry Driving: A Case Study

This study is aimed at exploring the influence of narrow coal pillars in gob-side entry driving (GSED) on the development height of the water-conducting fracture zone (WCFZ) in the fully mechanized caving face. In reference to the geological mining conditions of working face 11915 of Gequan (GQ) Coal Mine, the development law of the WCFZ in the GSED fully mechanized caving face was studied by means of formula calculation, on-site measurement, theoretical analysis, and simulation. The research results disclose that the development height of the WCFZ in the GSED fully mechanized caving face is affected by narrow coal pillars of GSED. When the narrow coal pillars lose stability, the overburden failure changes from insufficient mining to sufficient mining, and the WCFZ in the overburden changes from an arch-shaped one to a saddle-shaped one. Additionally, the development height of the WCFZ surges.