基于目前煤与瓦斯突出模拟试验均为人为控制突出口打开的实际情况,自主研制了可改变轴压、围压和孔隙压,实现突出口自行打开的煤与瓦斯突出模拟仪。以典型高瓦斯矿井-阜新孙家湾矿为例,试验模拟了煤层开采深度分别为900、1100、1300 m时,突出煤层临近工作面区域在地应力和瓦斯压力共同作用下诱导发生煤与瓦斯突出全过程。试验利用轴压、围压模拟地应力作用,孔隙压模拟瓦斯压力作用。经相似理论计算确定了3种开采深度下轴压和围压值、孔隙压逐级增加得到了突出时瓦斯压力,并拟合了关系曲线。研究结果表明:开采深度、轴压、围压、瓦斯压力与突出距离、突出强度间均呈幂指数增加规律。随深度增加,地应力与瓦斯压力对突出影响增量逐渐减小。瓦斯压力对突出影响作用存在3阶段特征,分别为急剧影响增加阶段、稳定影响增加阶段和缓慢影响增加阶段,确定了瓦斯压力对突出影响变化率最大值,即瓦斯压力变化异常区与稳定区分界点为0.75 MPa,对应开采深度为350 m,与前人理论分析结果基本吻合。由此可以推断,随深部开采,地应力与瓦斯压力共同作用下煤与瓦斯突出频度将增加,但强度和破坏程度增加率将趋于平缓。所得结论对该矿深部煤与瓦斯突出机制认识和预测防治具有参考意义。
Based on the practical situation that the opening of outburst mouth is man-made controlled in experiments of coal and gas outbursts, the simulation device of outburst is designed and developed which can change axial pressure, confining pressure and pore pressure. The outburst mouth can open by itself. Sunjiawan coal mine in Fuxin is a typical high gassy mine as example, the whole processes of outburst induced are simulated by experiments on conditions of joint action of stress and gas pressure near working face when mining depth is respectively 900 m, 1 100 m and 1 300 m. In experiments, axial pressure and confining pressure are used to simulate ground stress. And pore pressure is used to simulate gas pressure. According to similarity theory, axial pressure and confining pressure are determined in advance on condition of 900 m, 1 100 m and 1 300 m. With the step-by-step increment of pore pressure, the gas pressure of outburst is obtained. The relationship curves are presented. The results show that the relationship curves are all power exponent among mining depth, axial pressure, confining pressure, gas pressure and outburst distance, outburst intensity. With depths increasing, the influences of stress and gas pressure on the intensity increment of gas outburst are gradually decreased. The effect of the gas pressure on outburst presents three stages characteristics, dramatic stage, steady stage and slow stage of impact increasing. The gas pressure of 0.75 MPa is the threshold influenced on maximum rate of outburst. That is also cut-off point of gas pressure between abnormal and steady region, corresponding mining depth of 350 m, which is consistent with previous theoretical results. On the basis of analysis above, it can be presented that with deep mining, the frequency of coal and gas outbursts will increase on the joint action of stress and gas pressure. But the increment of impact strength and damage will decrease. The conclusions will have reference significance to mechanism, forecasting and prevention of gas