榆横北区巴拉素井田富水煤层特征

Characteristics of water-rich coal seam in Balasu Mine Field of northern Yuheng Mining Area

以陕北侏罗纪煤田榆横北区内巴拉素煤矿2号富水煤层为主要研究对象,对煤层的基本特征和裂隙特征进行研究;结合现场实测、室内实验、理论计算等方法手段,对煤层无机矿物组成、物理力学性质、煤体结构判别、煤体裂隙主要参数进行分析,研究2号富水煤层的主要特征。结果表明:相比其他非富水煤层,巴拉素井田2号富水煤层内的碳酸盐矿物和黏土矿物含量较低,煤体裂隙不易被充填堵塞;其煤层内的黄铁矿呈脉状、长条状分布,该赋存状态为流体沉淀的产物,反映了2号煤层内流体活跃的径流情况;2号富水煤层的抗压强度和弹性模量相对最小,在原始地应力的作用下更易产生塑性破坏,形成裂隙裂缝;该煤层煤体结构在部分区域呈碎裂结构煤;2号富水煤层一定程度上受区内小型构造影响,煤层裂隙的主要参数值远大于其它煤层,煤层裂隙平均密度为11.48条/m,煤体体积裂隙数为4.01条/m3,煤体完整性系数为0.72,煤层剖面裂隙率平均约3.12%;巴拉素井田2号煤层具备存储和运移地下水的优势介质条件。

This paper takes No.2 water-rich coal seam of Balasu Coal Mine in northern Yuheng Mining Area of Jurassic Coal Field in northern Shaanxi as the main research object,and studies the basic characteristics and fracture characteristics of the coal seam.Combined with field measurement,laboratory experiment,theoretical calculation and other methods,the inorganic mineral composition,physical and mechanical properties of coal seam,coal structure discrimination,coal crack main parameters and other analyses were carried out,and the major characteristics of No.2 water-rich coal seam were found.The results show that,compared with other non-water-rich coal seams,the contents of carbonate minerals and clay minerals in No.2 water-rich coal seam in Balasu Mine Field are lower,and the coal cracks are not easy to be filled and blocked.The pyrite in the coal seam is distributed in veins and strips.The occurrence state is the product of fluid precipitation,which reflects the active fluid runoff in No.2 coal seam.In addition,the No.2 water-rich coal seam has relatively small compressive strength and elastic modulus,and is more likely to produce plastic failure under the action of original in-situ stress,resulting in the formation of cracks.And the coal body structure of the coal seam is fractured coal in some areas.At the same time,the No.2 water-rich coal seam is affected by small structure in the area to a certain extent,and the main parameter value of coal seam fracture is much higher than that of other coal seams.That is,the average density of coal seam cracks is 11.48 per m,the number of coal volume cracks is 4.01 per m3,and the coal integrity coefficient is 0.72,the average fracture rate of coal seam section is about 3.12%.It is concluded that the No.2 coal seam in Balasu Mine Field has the advantageous medium conditions for storing and migrating groundwater.