Study on Mechanical Evolution Characteristics of Overburden Rock in “Knife Handle”-Type Fully Mechanized Top-Coal Caving Face

Compared with that of equal-length working faces, the mechanical evolution mechanism overburden rocks in “knife handle”-type mining sites is more complex. The form roof fracture knife handle-type mines variable, and stress distribution near interface concentrated, thereby severely threatening safety mining. To elucidate characteristics fully mechanized top-coal caving sites, geological conditions 22401 face Hanjiawa coal mine are investigated. FLAC3D software used to numerically simulate abutment pressure, horizontal stress, vertical displacement handle face. This provides an effective theoretical technical framework for subsequent problems, such as pressure control, management, support withdrawal under similar conditions. simulation results indicate when mined within range 20–30 m before after caving, considerably asymmetric, overconcentrated, maximum 18.41 MPa, 16.45 MPa. Influenced by self-weight, subsides floor bulges. sinkage 268.9 mm bottom drum 10.01 mm.