急倾斜煤层俯伪斜下保护层开采的卸压范围

Pressure-Relief Scope for the Exploiting of Steep-Inclined Oblique Under-Protecting Strata

以某煤矿急倾斜煤层俯伪斜下保护层开采为工程对象,采用有限元数值计算分析方法,从被保护层的应力和变形2个方面分析了保护层开采对被保护层的卸压程度和卸压保护范围;通过现场观测被保护层瓦斯动力参数变化,确定了被保护层实际的有效保护范围.2种方法得到的结果基本一致.结果表明:该矿井保护层开采后被保护层得到充分保护的倾向上部卸压角为90°、下部为82°,走向超前距离大于20 m,其被保护层卸压范围是一个近似椭圆型的卸压圈,卸压圈椭圆的中心区域是卸压效果最充分的区域,从卸压圈椭圆的中心到边界卸压效果逐渐减弱.

Finite element methods were used to simulate the stress and strain in a protected lay- er. These estimates were then used to determine the extent of pressure relief from the protec- ting layer. Structures similar to these are important when oblique mining in the protected layer. Dynamic parameters were observed in the field to determine the amount of protection. The two methods give congruent values. The pressure-relief angles in the protecting layer are 90° on the lower boundary and 82° on the upper boundary after removing the underlying layer. Effects from the protecting layer lead the strike by over 20 meters; the magnitude of the effects approximates an ellipse, becoming weaker from the center toward the boundary.