The existence of F16 fault in Yuejin Coal Mine directly affects the stress distribution state and stress concentration mode of the rock mass around 25110 fully mechanized caving face, which will cause the increase of the tectonic stress of rock mass, especially the increase of horizontal stress, and easily form stress concentration. The theoretical analysis and numerical simulation study on the structural characteristics of roof rock, the potential burst of coal seams and the roof stress distribution in the working face showed that the rock burst easily occurred due to the influence of F16 fault and under the action of tectonic stress, the mining disturbance and the rupture of the extra-thick main roof.

According to rock cross-cut coal uncovering under the condition of high ground pressure and high gas pressure in the depths of Daxing Coal Mine,it used high pressure rotating sealed joint and three wings reaming bit,it used the drilling rig to drive drilling pipe rotating,so that reaming drilling bit rotated to carry out high pressure water jet reaming,which strengthened pressure relief for gas pumping-exhaust.The technology and equipments were suitable for various angle drillings,coal cuttings discharged smoothly while the drilling was being reamed,remarkably improved the effects of coal drillings pressure relief and gas pumping-exhaust,it had important value for extending application.

The thermal analysis module of large-scale finite element software ANSYS10. 0 was adopted to do numerical computation for seepage field of gas,and variation of methane pressure distribution and seepage strength was analyzed for comprehensive digging tunnel and digging and blasting tunnel. Based on the effect of different digging process on gas outburst launch was analyzed. The results show that under the same condition,digging and blasting face compare comprehensive digging face,gas pressure is less than the latter,but the seep active region is larger than the latter,so it’s easier to lead to dynamic disaster due to the work of gas expansion.

永荣矿区在掘进-350 m水平深部砂岩巷道时出现岩石突出并伴随瓦斯的动力现象频繁发生.针对这种现象,从构造应力场、掘进应力场、自重应力场和中细粒砂岩物理力学性质等方面进行了分析,得出煤系地层岩巷掘进砂岩突出的机理.

The stress evolution of surrounding rock is a complicated process in the blast drivage of a coal roadway. In this paper, the shock wave induced by blasting was simplified as a pulse distribution load, a model for numerical study was established according to the actual conditions of the coal mine, the numerical simulation of the dynamic effect of shock action onto the surrounding rock was carried out by using the dynamic module of numerical sinulation software 3DEC of the discrete element, and the evolution law of both the vertical and horizontal stress in front of the drivage face was analyzed. The study showed that at the moment of blasting, the stress in coal body in front of the drivage face rapidly increased and then rapidly attenuated in the forward propagation process, the severe disturbance of stress may easily lead to the instability of coal body and thus cause the occurrence of the dynamic disasters.

The different gas geological element in the deep mine of Huainan Mining Area had a foretaste of an obvious dynamic phenomenon in the seam gateway heading.In order to effectively predict and control the coal and gas outburst accident occurred in the seam gateway heading under the complicated geological conditions in the deep mine,several study means in combined with the lab analysis and the site test were applied.The sensitive index and its critical value under the different geological conditions in the test area were obtained from the study and the normal geological condition was: S0 = 7 kg/m,K10 = 0.7 mL/(g·min1/2).The abnormal condition was: S0=6 kg/m,K10=0.5 mL/(g·min1/2).The results showed that the determined index and its critical value were rational and effective,which had improved the month heading rate in the test area from 62 m to 124 m and had a safety heading of 3 000 m in the test area.

The initial caving in the top coal caving is a complicated dynamic process.When the fully mechanized caving face propels forward cyclically,the seepage field structure of the coal mass gas changes.To discover the distribution and variation of the coal mass gas pressure in front of the fully mechanized caving face,further analysis the intrinsic gas energy,study the possibility of coal rock dynamic disasters during the primary caving period,and to have an effectively comprehensive gas control,this paper makes a simulation analysis of the gas pressure near the face stope based on the ANSYS10.0 transient analysis model.This study shows that the stress gradient in the distressed zone which is in front of the face changed greatly during the face propulsion,and the stress in the stress concentration regions is high while its gradient change is small;during the primary caving period,the stress gradient in front of the working face formed by the first cycle of the top caving is greater than that is formed by the second cycle of the top caving;gas expansion is beneficial to the outburst.

According to the different engineering mechanical states of top coal caving and normal stoping of gaseous loose thick coal seams, the dialectical relation between this caving method and dynamic disasters was analyzed by simulating the change of stress states in the process of top coal initial caving with different mining and caving ratios based on the ANSYS10.0. The variation of elastic energy and methane expansion energy during first top coal caving was analyzed by first weighting and periodic weighting and combining with coal stress and deformation distribution of top coal normal stoping as well as positive and negative examples in top coal caving of outburst coal seam. The research shows that the outburst risk increases along with the increase of the caving ratio in the initial mining stage. In the period of normal stoping, when the mining and caving ratio is smaller than 1:3 and hard and massive overlying strata do not exist (periodic weighting is not obvious), it is beneficial to control ground stress leading type outburst. Thus, it is unreasonable to prohibit top coal caving in dangerous and outburst prone areas.

The gas migration in coal body in front of the fully mechanized caving face mainly seepages along the coal seam surface to the mined-out space.When a fully mechanized caving face is cyclically advanced forward,the structure of the seepage field of coal body gas changed.Simulation analysis was made on the gas pressure near the fully mechanized caving face by using ANSYS10.0 transient analysis module in order to further probe into the variation regularity of gas pressure distribution in the coal body in front of the fully mechanized caving face and effectively control the gas.Study indicated that the varying gradient of gas pressure in the stress-lowering zone in front of the fully mechanized caving face is large,but in the stress-increasing zone,the gas pressure is relatively high and the varying gradient of gas pressure is small;the gradient of gas pressure formed in the first coal-caving cycle in front of the face is larger than that in the second coal-caving cycle.

The stress variation of roof coal seam with different ratio of excavating thickness to caving thickness in its initial caving process was analyzed, and the variation of elastic energy and potential energy of roof coal seam was analyzed as well. The results show that the outburst risk increase along with the increase of the ratio of excavating thickness to caving thickness under the same conditions.

针对传统水力扩孔存在的问题,研制了旋转水尾及扩孔钻头,利用钻机带动钻杆进行高压水扩孔.试验表明该套扩孔钻具适用于不同角度钻孔,扩孔排渣顺畅,扩孔后钻孔直径增大了3～9倍,显著提高了煤孔卸压、抽排瓦斯效果,具有重要的推广应用价值.

为实现对喷嘴结构和参数的优化,设计更适用于煤层钻孔的高压水射流喷嘴,利用射流冲击压力分布测试装置,对高压水射流冲击压力在射流纵横断面的分布及变化规律进行了实验研究,并对射流冲击压力的分布进行了数值模拟.研究表明:在淹没条件下,随着径向距离的增加,射流冲击压力不断降低,射流颗粒具有的能量越来越小;随着轴向距离的增加,存在等速核区,超过等速核区,射流冲击压力明显降低.

采用数值模拟与工作面突出危险性预测指标考察相结合的方法,对急倾斜特厚突出煤层分层开采自保护范围进行了研究,其成果对类似矿井防突具有参考意义.

Study on erosive mechanism of coal by water jet was conducted with the method combining the theoretical analysis, experimental test and numerical research, which laid a theoretical foundation for the selection of high-pressure water jet nozzle and jet parameters suitable for seam boreholes. The paper simultaneously discussed the destructive effect of high-pressured water jet to the coal body, the destructive effect of the earlier stress wave as well as the destructive effect of the static pressure of the later water jet and the stagnation pressure gradient.

针对高瓦斯及突出煤层顺层瓦斯抽放钻孔施工困难的问题,寻求一种新的钻孔施工技术.通过对煤矿井下煤层地质条件的分析,对孔底液压马达驱动钻头旋转结合水射流破煤的钻孔技术进行了试验研究.试验表明:该钻孔工艺技术有利于充分利用水力能量,降低钻杆磨损,减少了钻杆折断的概率;新型PDC钻头能更好地与煤层相适应,大幅度地提高了破煤效率,提高了钻进速度.