RELATIONSHIP BETWEEM DIP ANGLE OF COAL SEAM AND HEIGHT OF THREE ZONES

Determination of heights of three zones(inbreak, crack, and bent zones) of mined out area provides a basis for predicting deformatiom and fracture of earths surface. Among several factors,dip angle of coal seam is the most important factor affecting the height of the three zones. Determination of heights of three zones from experience data if of certain artificial character. Relationship between height of inbreak zone and fracture zone and dip angle of steeply dipping coal seam has been discussed. In the paper, a method for determination of heights of three zones through analsysing redistrbution of gragh of stress which if obataine from non linear finite element simulation in moderately and gently dipping seam is proposed. Then, we predict the heights of three zones in two by this method.