Combined with the characteristics of the mined-out area under Lishi—Jundu highway in Shanxi Province,the grouting in mined-out areas,drilling data and the related relationship between the mined-out area span,time,and residual subsidence are put forward;and the distortion anticipation methods and corresponding formulas are also presente.

With increasing development of digital and communication monitoring techniques, the quantity of obtained information about the adamage process of rock mass around large scale mined-out areas is significantly increased.

33) composed of coal-gangue base composite medium close-by a large scale mined-out area, protecting slope difficultly, extraordinary induced debris flow derived hazard easily, etc.

Experiment on dynamical damage of overburden-rock media at various scale mined-out area in excavation disturbed zone;

The results of calculation indicate that a parts of ceiling, where there are some faults and cracks, are about to collapse when the stope span reaches to 6 m; and the middle parts of ceiling starts to collapse when the stope span is 10 m.