采场上覆巨厚坚硬岩浆岩致灾机理与防控措施

为控制巨厚坚硬覆岩导致的采场矿压灾害，采用物理模拟、理论分析与数值模拟方法，研究采场上方厚约100 m岩浆岩的变形破坏特征及对采场围岩应力分布的影响，并分析其引发采场矿压事故的力学机理与显现形式。研究表明：巨厚岩浆岩与煤层间距较小时，可采用两端固支梁模型计算岩浆岩的破断垮距，间距较大时，采用薄板理论计算岩浆岩的极限挠度，并根据自由下沉空间确定其是否破断与破断步距；岩浆岩处于弯曲下沉带时，给工作面带来冲击矿压隐患，处于断裂带时，给工作面带来冲击矿压和大面积来压双重隐患。实践证明，巨厚坚硬岩浆岩下开采，可采取加强支护质量监测与提高工作面推进速度的方法，辅以坚硬顶板强度弱化手段消除冲击矿压和顶板强来压显现事故。

Disaster-causing mechanism and control measures of extremely thick and hard magmatic rock above working face

To avoid rock pressure accident of working face induced by thick and hard stratums in overlying strata，physical simulation，theoretical analysis and numerical simulation method was adopted to study the deformation and breakage characteristics of the magmatic rock of about 100 m thick above the working face and its impact on the stress distribution of surrounding rock of working face.It also gave an analysis on the mechanism and behaviors model of rock pressure accident induced by thick magmatic rock.The results show that doubly-clamped beam model can be adopted to calculate the first breaking span of magmatic rock when it is near the coal seam，otherwise the thin plate theory should be used to calculate the limited deflection of magmatic rock to judge it’s broken or not based in its free subsidence space and give the breaking span.Thick magmatic rock may cause pressure bump in working face when it belongs to sagging zone and cause pressure bump and large roof pressurization when it belongs to fractured zone.Field application proves that enhancing the support quality monitor and raising the advance speed with the roof strength weaken method are valid measures to reduce pressure bump and strong strata pressure accident caused by thick and hard magmatic rock.