Abstract: The mechanics model is established according to the mechanics parameters of rocks and the exploitation technical conditions of Qinqiu coal mine. By using 3-D explicit finite difference FLAC3D software, the situation of stress, displacement and failure are simulated from open-off cut to full mining to determine the height of water flowing fractured zone in overlying strata as the coalface advanced. That height is calculated by empirical formula and is detected on spot by drilling piecewise injection method. It is approved that the numerical simulation method can provide ideal prediction accuracy, thus providing a new, simple and reliable method to predict the height of water flowing fractured zone.  

Key words: Overlying strata movement, Height of water flowing fractured zone, Numerical simulation, Detection