The lay of the strata can imply that the rock splits easily along its directionof cleavage .
成层的地层意味着岩石易于沿着其解理方向裂开。
2
Conclusions Although void formed due to underground mining is the origin of the strata movement, side confinement of the strata played important role for the directionof the movement.
结论虽然由于无效形成地下开采，是地层运动起源，地层侧隔离发挥了该运动方向的重要作用。
3
By analyzing the geological characteristics, function of coal gathering, coal measures strata and burial conditions of Jiyuan area, it is pointed out the prospecting direction for coal field.