The Law of Fracture Evolution of Overlying Strata and Gas Emission in Goaf under the Influence of Mining
The Law of Fracture Evolution of Overlying Strata and Gas Emission in Goaf under the Influence of Mining
复制标题
采矿影响下采空区覆岩裂隙演化规律及瓦斯涌出
DOI：
10.1155/2021/2752582
复制
发表时间：
2021-08-12
期刊：
影响因子：
1.7
通讯作者：
Liu, Chao
中科院分区：
文献类型：
--
作者：
Cheng, Cheng;Cheng, Xiaoyu;Liu, Chao
在生产期间，由于采空区涌出卸压瓦斯，采矿的安全性较差。本研究以山西王家岭煤矿12322工作面中国为研究对象，通过物理模拟和现场观测相结合的方法，对该工作面进行了研究。该矿在回采过程中存在采空区上覆岩层破裂的特点。利用工作面瓦斯涌出与瓦斯运移的数学模型和有限元软件COMSOL，模拟了采动影响下上覆岩层裂隙地区的瓦斯运移规律。利用模拟结果探讨了卸压瓦斯在采空区内的分布规律。根据试验结果，设计了采空区卸压瓦斯抽放高位定向长孔的合理参数。结果表明，上覆地层裂隙发育受采矿影响较大。此外，断裂区连通后形成“梯形台地结构”。采场冒落带最大高度为2 6.8~2 8.1 m，裂隙带最大高度约为1 1 0 m，瓦斯浓度在走向切面上呈马鞍形分布。此外，瓦斯浓度从进风巷道到回风巷道总体呈上升趋势，达到最大值后逐渐降低。在垂直方向上，瓦斯浓度随层内浓度的增加而增大，瓦斯浓度最高点的位置逐渐向进风巷道方向移动。根据模拟结果，设计了高定向深孔的施工参数。稳定回采和稳定回采后，工作面上拐角瓦斯最大浓度为0.49%，回风最大瓦斯浓度为0.34%。研究结果为研究采动影响下上覆岩层裂隙演化规律和采空区瓦斯运移规律提供了依据。这些研究成果为降低工作面或回风巷拐角瓦斯超限，从而提高煤矿的安全生产能力提供了依据。
Mining is associated with poor safety due to pressure relief gas emission from the goaf during the production period. The aim of this study was to explore a case study of the Wangjialing coal mine 12322 working face in Shanxi, China, through physical simulation and field observation. The mine is characterized by overlying strata fracture in goaf during the process of working face mining. A mathematical model of gas source emission from the working face and gas migration and the finite element COMSOL software were used to simulate the law of gas migration in the region with overlying strata fissures under the influence of mining. The simulation results were used to explore the law of distribution of pressure relief gas in goaf. Rational parameters of the high-level directional long borehole for the pressure relief gas extraction in goaf were designed based on experimental results. The results showed that the development of the region with overlying strata fissures is affected by mining. In addition, the “trapezoid platform structure” is formed after fracture areas are connected. The maximum height of the stope caving zone was between 26.8 m and 28.1 m, and the maximum height of the fracture zone was approximately 110 m. The gas concentration exhibited a saddle-shaped distribution on the cut surface of the direction of the strike. Furthermore, the gas concentration showed an overall upward trend from the intake airflow roadway to the return airflow roadway and gradually decreased after reaching the maximum. In the vertical direction, gas concentration increased with the increase in the layer, and the position of the highest point of gas concentration gradually shifted to the direction of the intake airflow roadway. Construction parameters of the high directional long borehole were designed through simulation results. After steady extraction and stable extraction, the maximum gas concentration in the upper corner of the working face was 0.49%, and the maximum gas concentration in return airflow was 0.34%. The findings of this study provide information on the law of fracture evolution of overlying strata and gas migration in goaf under the influence of mining. These findings provide a basis for reducing gas overlimit in the working face or return airway corner, thus improving the safety production capacity of the coal mine.