下保护层开采卸压效应研究

发布时间：2018-10-17 22:21

【摘要】：实践证明保护层开采是预防煤与瓦斯突出最有效的区域防突措施；而卸压效应与覆岩条件密切相关。本文针对三种覆岩模型,运用UDEC数值模拟软件研究了层间距、层间岩层岩性、层间关键层位置、被保护层上关键层厚度以及关键层的破断距等不同开采因素下保护层开采卸压效应,研究表明：(1)层间距越大,被保护层膨胀率越低、卸压系数越小。(2)随着层间岩层硬度的增加,卸压始动距增加,卸压程度减小；被保护层膨胀率、膨胀区间有所增加。(3)层间关键层层位越高、破断距越长,被保护层裂隙发育不明显,卸压效果越差。(4)被保护层上方关键层厚度、破断距增加,被保护层卸压特征参数越大,越利于被保护层的卸压与瓦斯解吸。在相同层间距条件下,详细分析了不同采场覆岩数值模型采动过程中煤岩应力分布、卸压煤层变形特征、裂隙场动态演化与时空关系、关键层破断前后以及破断距离增加后煤岩层卸压效应,得出结论：(1)三种模型沿走向应力分区、膨胀分区特性相同,各个区间的宽度及时间不同,有明显的时间效应；(2)关键层的位置以及破断距离对煤岩裂隙场演化、应力分布、膨胀变形规律的影响很大。上述结论为下保护层开采实现区域性预防煤与瓦斯突出提供一定的理论依据。
[Abstract]:It has been proved that the mining of protective layer is the most effective measure to prevent coal and gas outburst, and the pressure relief effect is closely related to the overburden condition. In this paper, for three kinds of overburden models, the interval between layers, the lithology of interlayer and the position of key layer between layers are studied by using UDEC numerical simulation software. Under different mining factors, such as the thickness of the key layer on the protected layer and the breaking distance of the critical layer, the research shows that: (1) the bigger the interval between the layers, the lower the expansion rate of the protected layer, The pressure relief coefficient is smaller. (2) with the increase of interlayer hardness, the initial pressure relief distance increases and the pressure relief degree decreases, while the expansion rate of the protected layer increases, and the expansion interval increases. (3) the higher the key layer position between layers, the longer the fracture distance. (4) the thickness of the key layer above the protective layer and the breaking fault distance increase, the larger the characteristic parameters of the protected layer is, the more favorable the pressure relief and gas desorption of the protected layer are. Under the condition of the same interval, the stress distribution of coal and rock, the deformation characteristics of pressure relief coal seam, the dynamic evolution of fracture field and the relationship between time and space in mining process of overburden rock in different stope are analyzed in detail. The results show that: (1) the three models have the same characteristics of expansion zone along the strike stress zone, the width and time of each interval are different and have obvious time effect; (2) the location of the critical layer and the breaking distance have great influence on the evolution, stress distribution and expansion deformation of the fracture field of coal and rock. The above conclusions provide some theoretical basis for regional prevention of coal and gas outburst.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TD713;TD32

【参考文献】