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In order to study the mechanism and effective countermeasures of floor heave in large section mining roadway, one of its prediction methods was put forward through theoretical deduction. It is showed that floor rock beam with lower critical stress is easier to instability, along with larger section of mining roadway. Almost all large section roadway are subject to the threat of floor heave under horizontal force. Moreover, with the increasing width of tunnel, the heave volume increases approximately linearly. At the same time, three kinds of support scheme, roadway support, reinforcement of sides, comers and roof, were analysed with Ansys. A conclusion is drawn that floor heave can be controlled well by installing roof bolting based on floor on a small scale with the reinforcement of working slope, angle and roof. [ABSTRACT FROM AUTHOR]

Based on the condition of No. 1-2 coal seam of Shendong minging area Shangwan Coal Mine, the caving characteristics, the fracture position and caving zone and fracture zone "two belts" height of the 5.5 m large mining height workface's roof were studied by similar simulation test, with geometric similarity ratio 1 : 50. The results show that the immediate roof eaves stratified to loose blocks, and the goal can not be full of these loose blocks; because of the increasing of mining height at one time, and the original immediate roof is far from full of goal, the lower basic roof can not form hinge structure after it collapse, and the increasing of mining height evolves into the increasing of immidiate roof; before periodic weighting, fracture position of roof usually advance beyond working face 7.65 m; the height of two belts presents step increasing. [ABSTRACT FROM AUTHOR]