特厚煤层顶煤深孔预裂爆破技术研究

针对潘津煤矿二采区23-25号煤层赋存条件，提出采用深孔预裂爆破的方式来弱化顶板；基于断裂力学、爆炸动力学分析了顶煤深孔预裂爆破原理及煤体爆破破坏分区特征；根据前人的研究成果及煤体力学特征，合理地对炸药类型、不耦合系数、封孔系数及起爆方式等爆破参数进行分析，利用数值分析软件ANSYS LS_DYNA确定了最优不耦合系数为1.25，封孔系数为0.25；依据确定的最终参数计算得到爆破下顶煤破碎区半径、裂隙区半径分别为0.836 4、3.942 6 m，弹性震动区半径约5.6 m，并确定炮孔间距为8 m。基于工作面的工程地质条件，提出了两巷超前预裂深孔爆破的顶煤预裂方案，该方案应用于工程实践后，能有效地弱化顶板，提高回采率。

Study on deep hole presplitting blasting technology of top coal in extra thick seam

According to the occurrence conditions of No.23-25 coal seam in No.2 mining area of Panjin Coal Mine，deep hole presplitting blasting was proposed to weaken the roof；based on fracture mechanics and explosion dynamics，the principle of top coal deep hole presplitting blasting and the zonal characteristics of coal blasting damage were analyzed；according to the previous research results and coal mechanical characteristics，reasonable blasting parameters such as explosive type，uncoupled coefficient，hole sealing coefficient and initiation mode were analyzed，and numerical analysis software ANSYS LS_ DYNA was used to determine the optimal uncoupling coefficient as 1.25 and sealing coefficient as 0.25；according to the determined final parameters，the radius of top coal fracture area and fracture area are 0.836 4 m and 3.942 6 m respectively，and the radius of elastic vibration area is about 5.6 m.The spacing between blastholes is 8 m.Finally，based on the engineering geological conditions of the working face，the top coal presplitting scheme of two roadway advanced presplitting deep hole blasting was proposed.After the scheme is applied to engineering practice，it can effectively weaken the roof and improve the recovery rate.