TY - JOUR
TI - Research on the mechanism and practice of fracture initiation during hydraulic fracturing in hard roofs of coal mine
AU - Deng Qigen
AU - Yang Yanjie
AU - Zhao Fajun
AU - Du Yinsheng
JN - Thermal Science
PY - 2023
VL - 27
IS - 3
SP - 1827
EP - 1834
PT - Article
AB - A hydraulic fracture extension model was established, an extension criterion  and an extension mode of hydraulic fracture were analyzed, and the  theoretical prediction was compared with the practical results, a good  agreement was observed. Furthermore, the direction of hydraulic fracture  extension was also discussed, the results showed that the hydraulic fracture  propagates from the cut to the bedding plane, forming a complex mixture of  longitudinal and transverse fractures fracture network. The hydraulic  fracture extension direction is influenced by its extension critical pressure  and its extension pressure in the rock formation. Practice shows that  hydraulic fracturing can effectively weaken the strength and integrity of  the roof, so that the roof in the mining area can collapse in layers and  stages. The present theoretical analysis can be used for reducing or  eliminating the hazard of the hard roof to the working faces.