复采工作面过空巷顶板稳定性

针对复采工作面过平行空巷支架支护阻力计算的问题，通过现场调研和理论分析，建立了过空巷采场基本顶破断的力学模型，提出了影响复采采场基本顶超前断裂的3个因素：复采工作面与空巷间煤柱宽度、复采工作面与周期断裂线距离、空巷宽度。通过对影响因素的力学分析，得到了基本顶超前断裂的力学作用机理：复采工作面与空巷间煤柱随回采失稳，导致顶板失去煤柱支撑，基本顶梁结构的悬臂长度增加，当悬臂长度达到周期来压步距时，悬臂梁在固支端断裂。基于Bieniawski公式，推导得到了复采工作面与空巷间煤柱失稳的临界宽度W*和复采工作面基本顶必然产生超前断裂空巷临界宽度A0。根据过空巷采场基本顶破断力学模型对基本顶来压力学模型中断裂岩块尺寸进行了针对性调整，运用调整断裂岩块尺寸后的基本顶来压力学模型计算得到了适用于复采工作面的过空巷期间支架最小支护强度为10 910.77 kN/架。圣华煤业复采工作面过空巷期间的矿压观测结果表明：工作面过空巷期间，最大工作阻力为9 656 kN/架，支架支护强度计算合理。

Roof stability for repeated mining workface passing through abandoned parallel gateway

According to calculating of the support strength when the repeated mining face passing through abandoned parallel gateway,a mechanical model for studying the principle of main roof fracture was established through spot investigation and analysis for fracture of roof of workface.Three factors such as the width of coal pillar between repeated mining face and abandoned parallel gateway,the distance between repeated mining face and main roof fracture line and the width of abandoned parallel roadways which may lead to the advanced fracture of main roof was put forward.Through the analysis of the three factors,the mechanical mechanism of advanced fracture of main roof was obtained.It shows that the coal pillars become destabilization when coal being extracted.The destabilization of the coal pillars leaves roof beam unsupported and increases the length of cantilever beam.When the length of cantilever beam is greater than or equal to cycle weighting interval,the cantilever beam breaks.Based on the Bieniawski formula,the critical width of coal pillar that becomes destabilization and the critical width of abandoned parallel gateway that main roof inevitably breaks in advance are calculated.The size of broken rock block of mechanical model of main roof weighting is adjusted on the basis of the mechanical model of main roof fracture.The adjustment is used to calculate the support strength of hydraulic support when repeated mining face passing through abandoned parallel gateway.It shows that the least support strength is 10 910.77 kN.On-the-spot observation results show that the support strength is 9 656 kN when repeated mining face passing through abandoned parallel gateway.