仰采,俯采老顶岩层断裂特征及对直接顶稳定性的影响

本文将倾斜长壁仰斜、俯斜开采的老顶岩层视为倾斜弹性板。当板的长短跨度之比＞２时，板的荷载主要由短跨边来承担。据此，笔者沿工作面推进方向截取单位宽度的倾斜岩梁建立了老顶初次来压和周期来压的力学模型。分析表明，仰斜开采时的周期来压步距和支承压力小于俯斜开采，两者的支承压力分布规律有明显的差别，矿压显现程度仰采较俯采严重。证实了仰斜开采时直接顶稳定性较差、顶板事故较多主要是岩层受层向分力作用和煤壁片帮所致。当层向分力与工作面推进方向一致时，直接顶的稳定性较好，反之就差。从顶板管理的角度出发，作者提出了在有条件的矿井应优先选择俯斜开采。

FRACTURING CHARACTERISTICS OF MAIN ROOF STRATA WHEN MINING UPHILL AND DOWNHILL AND ITS EFFECT ON STABILITY OF IMMEDIATE ROOF

The paper regards the main roof strata in uphill and downhill mining of an inclined longwall as a elastic plate. When the ratio of long and short span is greater than 2,the load of plate is mainly carried by the short span.Based on this.the authors take a unit width of an inclined rock beam in the direction of face advance,and a mechanical model for studying initial and periodic weighting of the main roof was established.It shows that the interval of periodic weighting and abutment pressure in uphill mining are less than downhill mining.And distribution of abutment pressure in both cases is quite different.Manifestation of ground pressure in uphill mining is more evident than downhill mining.It is proved that when uphill mining is introduced,the immediate roof is less stable,and roof failures are frequent due to component in the direction of rock strata and due to spalling of coal rib.When the direction of component and a face advance are the same,the immediate roof is more stable.On the contrary,the vice versa.From the roof control point of view,the authors propose to give priority to downhill mining where conditions are favorable.