急斜煤层分段放顶煤开采合理段高选择研究

为确定急斜煤层水平分段综放开采条件下工作面段高的合理取值,将开采后裸露顶板岩层简化为三边固支的矩形薄板,采用薄板破断理论对受横向和纵向载荷作用下的斜置矩形薄岩板进行力学分析.研究表明:岩板走向长度、倾斜长度、岩层倾角、覆岩载荷及泊松比是影响段高取值的5个主要因素.应以在工作面上方采空区煤矸体沿着顶煤采出后形成的槽形采空区域下移前岩板不发生沿根部折断为极限段高的选择标准.工作面合理段高取值分为3类:第Ⅰ类煤层倾角45°～55°,取值在29 m范围内;第Ⅱ类55°～75°,取值在51 m范围内;第Ⅲ类75°～90°,该范围内开采工艺及设备选择对合理段高取值的影响更为重要.

Selection of Reasonable Section Heights During Top-coal Caving to Steep Seams

Estimation of reasonable face-section heights during horizontal top-coal caving to steep seams was studied. Bare roof strata were modeled as simplified, trilateral, clamped, ob-lique, rectangular thin plates subject to lateral and longitudinal loads. The five main factors af-fecting section height are: the length of the strata plate; the length of the incline; the angle of the strata; the load from the overburden; and, the Poisson ratio of the rock. The standard for choosing the limit to the section height is that the strata plate don't break before coal and re-fuse in the gob area can move down the trough shaped gob after the overlying coal has been ex-cavated. Reasonable section heights may be divided into three categories. First, for a seam in-clination of 45° to 55°, about 29 meters. Second, for inclinations of 55° to 75° a height in the range of 51 meters. And, third, for inclinations from 75 o to 90° the choice of mining technolo-gy and equipment is more important than the choice of section height. This study will help pre-vent the risk of large-scale roof collapse during production at the working face.