Technology of Floor Heave Prevention and Control in Fully-Mechanized Thick Seam Top Coal Caving Mining Face with High Intensity Mining

In order to improve mining efficiency of a fully- mechanized top coal caving mining face in thick seam, the similar simulation, numerical analysis, site mo nitoring and measuring and other means were applied to analyze obvious mine strata pressure behavior, serious gateway floor heave and other mechanism faced by a high intensity mining of a fully- mechanized top coal caving mining face. According to the roof failure features of the overburden strata and the coal and rock movement law, a study was conducted on the mine strata pressure behavior features, gateway floor heave deformation features and others. The results showed that under the min ing influences of the gateway two sidewall, the floor strata of the mining gateway had a zero displacement isoline and a zero strain isoline, the max depth of the zero di splacement point in the floor was determined as 1. 9 m and the max depth of the zero strain point was 3. 4 m. Thus the key technology of the gateway floor heave contr ol for the high intensity mining of the fully- mechanized top coal caving mining face was provided. The key technology would apply through anchors, additional high stre ngth yield bolts and others to enhance the support of the two sidewalls and apply a2. 4 m long hydraulic swelling bolt to fix a bolt end in a tensile strain compressed zon e of floor. An active anchoring force of the bolt and an additional anchoring force of the bolt provided by the downward compression of the surrounding rock at the anch oring end were applied to increase a flexural rigidity of the floor strata and to limit the floor heave. Meanwhile, the bolt at the floor corner of the floor should be set with a 45° angle to limit a high shearing stress role within the scope.