Study of formation mechanism of floor heave at goaf side of roadway and prevention technology

The floor heave of deep goaf side coal roadway has bocome increasingly common and serious phenomenon; it has important affection on carriage and normal use of roadway, and the prevention technology research of the floor heave has become the key of coal mine rock mechanics problems at present. Through theoretical analysis, numerical simulation and field tests, a detailed search has been done on the floor heave characteristic of goaf side of roadway, the formation reasons, the formation mechanism and control technology. It is concluded as follows. (1) The floor heave of goaf side has some connection with the floor lithologic and floor strata stress distribution. (2) The roadway floor ruptures. uplifts and the floor corner moving outward in serious circumstances are the major cause of the floor heave formation. (3) The floor heave starts at the floor corner and the central part of roadway. (4) Using the hollow bolt grouting and high-strength bolt jointed support technology can control effectively the floor heave of goaf side of roadway.