For Guocun coal mine

Yuzhou city

the goaf surface has formed 1 700 m long and 400 m wide moving basin; the goaf overlying rock mass is a typical "three zones" (in break

crack and bent zones) in South-to-North water diversion project. High precious monitoring networks are installed to research the goaf deformation characteristics during construction. The monitoring results indicate that the surface moving is over before construction. The surface moving in grouting area is obviously because of grouting; and the surface moving tends to stable after grouting. The deformation and stress of channel and goaf in three working conditions no-leakage

common-leakage and severe-leakage are simulated by FLAC3D. The vertical displacement and effect depth increase with leakage become more serious but added value decreases; the maximum value is 5.5 cm; effect width is symmetrical along the channel and increases uniformly; horizontal displacement increases and added value increases

while the maximum value is only 7 mm.; grouting redistributes stress field and there is stress concentration at both ends of goaf area; during leakage working conditions there is no effect on goaf area from water and channel load.