寺河矿正断层附近瓦斯涌出量变化规律研究

On the changing regularity of the gas emission due to the normal neighboring faults in Sihe Coal Mine

查明不同倾角正断层附近瓦斯涌出量变化规律对及时进行风量调整,保障煤矿安全生产有重要意义。以寺河矿煤田勘探开发资料为基础,在系统分析断层附近煤层顶、底板岩性、力学性质、原始状态下应力分布状况等的基础上,借助Ansys软件分别构建了倾角13°和65°正断层的地质模型;根据该区应力测试结果,应用Flac3D数值模拟软件,模拟了两种倾角下断层附近应力场分布规律;采集煤样,模拟现场围压,进行了不同应力下煤岩渗透性试验,得出应力-应变-渗透率之间的关系;根据应力模拟结果,结合渗透率测试试验,得出研究区正断层附近渗透率分布规律;根据瓦斯含量、渗透率和瓦斯涌出量之间的关系,最终得出断层附近瓦斯涌出量变化规律。结果表明:应力-应变-渗透率具有较好的一致性,从断层附近到远处,渗透率表现为"减小—过渡—增大—正常"的变化规律,瓦斯涌出量表现为"增大—减小—正常"的变化规律。预测结果与现场实测数据对比显示,该预测结果具有一定的准确性。

The present paper is dedicated to the study of the changing regularity of the gas emission due to the normal neighboring faults in Sihe Coal Mine so as to guarantee the timely adjustment of the air flow and production safety of the coal mines in different dips. In pro- ceeding with our study, we have prepared the geological models in 13 degrees and 65 degrees of the normal faults by using the Ansys soft- ware on the basis of the coal field prospect and exploitation data and the systematic analysis of the lithology and mechanical features of the rock on the roof and bottom layers of the coM seam, the original stress distribution in the circumference of the normal faults. And, then, we have simulated the stress field distribution regularity in two angles about the normal faults based on the stress testing results with the help of the Flac3D numerical simulation software. Having collect- ed enough coal specimens, simulating the confining pressure and test- ing the coal permeability in different stresses, we have worked out the relationship among the stress, strain and permeability. And, finally, we have analyzed the stress simulation results, along with the perme- ability experiment tests, thus finding the permeability changing regu- larity at the neighborhood normal faults. The results of our study show that there exists obvious consistence among the stress, strain and per- meability. From the nearby faults to the far-off ones, the permeability has been found to reveal the changing regularity of ＂reduction - tran- sition - increase - normal＂, whereas the gas emission regularity tends to be in ＂increase - reduction - normal ＂. Thus, it can be seen that the forecasting results are of a certain accuracy through comparison.