一、前言采场老顶岩层随采场推进呈现周期性运动,其周期性运动步距即来压步距是由很多复杂因素所决定的,例如与顶板岩层分层厚度、强度、结构面(节理裂隙)分布、工作面长度、煤层倾角、推进速度、支护强度等多因素有关。由于赋存条件复杂及构造运动的影响,顶板岩层分层厚度与强度、结构面分布、煤层倾角等在工作面推进方向是变化的,因此实践表明来压步距是变化的。不仅 I. Preface The stope of the old roof stope shows periodic movement along with the stope. The periodic step-by-step pressure step is determined by many complex factors, such as the layer thickness, strength, structural plane Joint fissures) distribution, working face length, coal seam inclination, propulsion speed, support strength and other factors. Because of the complicated occurrence conditions and the influence of tectonic movement, the thickness and intensity of delamination, the distribution of structural plane and the dip of coal seam in the working face are changed in practice. Therefore, the practice shows that the pressure step varies. not only