三软煤层回采支承压力分布及支护构件受力规律研究

Distribution of advance abutment pressure and stress law of supporting components in three soft coal seam mining

为解决三软煤层采场侧向支承压力无法直接测量的问题,明确不同支护方案下采场超前压力分布有无差异等采动规律,以刀把式工作面——梁家煤矿4606工作面为依托,通过4606改造切眼位移变化间接获取工作面侧向支承压力分布规律,开展采动对4606材料巷不同支护方案下围岩控制效果对比,采用无损检测对锚杆(索)在回采期间受力情况进行分析。4606改造切眼距工作面110 m开始受到回采影响,距工作面68 m进入明显影响区,距工作面35 m进入剧烈影响区。距工作面侧向20 m以内为侧向支承压力影响峰值区,55 m以内为影响区。不同支护方案下,工作面超前支承压力分布范围区别较小,相差仅在5~10 m,超前支承压力影响剧烈范围为20~30 m;超前支承压力影响明显范围为30~60 m;超前支承压力影响范围平均为120 m左右,最大为160 m。巷道肩部锚杆受力超出屈服荷载,与拱架基本在拱肩处发生断裂吻合较好。巷道不同部位锚杆受力呈现出肩部>帮部>底角的特征。距工作面60m以外,单体支架支护强度满足使用要求;距工作面30m以内支架受力显著增加,出现挤压支架情况。研究成果补充了软弱煤层采动矿压显现规律。

In view of the incapability of directly measuring the lateral abutment pressure in the three soft coal seams, with clarification of differences in advance pressure distribution under different support schemes, and with the knife-handle-shaped working face—working face 4606 of Liangjia Coalmine as engineering background, the distribution law of lateral abutment pressure of working face was obtained indirectly by changes of displacement in transform cut 4606, the comparison of control effect of surrounding rock during mining under different support schemes of material roadway 4606 was carried out, and the stress condition of bolt(cable) during mining was analyzed by using non-destructive testing. Results have shown that transform cut 4606 was affected by mining when it is at 110 m from the working face;the cut enters the obvious influence zone at 68 m and a severe influence zone at 35 m.The influence peak area of lateral abutment pressure is within 20 m from the working face, and the influence area is within 55 m. Under different support schemes, the difference of advance abutment pressure distribution is small with the difference ranging only about 5-10 m, the influence range of advance abutment pressure 20-30 m, the obvious range of advance abutment pressure 30-60 m, the average influence range of advance abutment pressure about 120 m, and the maximum 160 m. The stress of bolt in roadway shoulder exceeds the yield load, which is in good agreement with the fracture of arch frame at arch shoulder. The stress in different parts follows the order of shoulder > upper part >foot. The strength of single support can meet the use requirements beyond 60 m from the working face;the stress of the support increases significantly within 30 m from the working face, and the support is squeezed. The research results supplement the ground pressure behavior law of weak coal seam mining on site.