Field Research on Ground Subsidence Rules of Intensive Fully-Mechanized Mining by Sublevel Caving

In order to provide field survey data for the consolidation of Sihe river dyke,20 times of ground subsidence observation on ground subsidence were specially made above No.1312 intensive fully-mechanized caving face(fast advancing speed,high recovery rate,and big width/depth ratio) of Baodian coal mine beneath the dyke.By analyzing and studying the survey data,we have obtained ground movement and deformation rules and different kinds of angle parameters as well as prediction parameters under the condition of intensive fully-mechanized caving in this area.Compared with the observation results about conventional fully-mechanized caving face,the amount of ground subsidence and degree of surface deformation after the intensive fully-mechanized caving are larger and more serious,and the deformation values are more concentrated,the subsided basin steeper,and the subsiding velocity faster,with the maximum velocity being 375 mm/d.