开滦范各庄井田12煤层底板突水危险性的地质评价

Geologic Evaluation of Water Inrush Risk for No.12 Coal Seam Floor of Fangezhuang Mine Field in Kailuan

根据隔水层的岩性和结构特征,提出了评价隔水层隔水性能的岩性-结构评价方法;并在突水系数中考虑隔水层的岩性-结构特征,提出了煤层底板突水危险性评价分类.针对开滦范各庄井田12煤层底板突水地质条件实际,系统分析了12煤层底板砂岩裂隙含水层厚度及其特征、隔水层的岩性及其分布和断裂构造条件,对开滦范各庄井田12煤层底板突水危险性进行了评价.研究表明,煤层底板隔水性能取决于隔水层岩性和断裂构造,随着底板泥岩百分比含量和厚度的增加,隔水层抵抗水压的能力增强,隔水性能变好;随着断裂发育程度的增加,底板隔水层由完整结构、块裂结构到碎裂结构和松散结构,底板隔水性能降低,且完整底板泥岩层的抗水能力明显大于含裂隙的底板泥岩层.开滦范各庄井田12煤层底板发生突水的水源以12～14煤层间砂岩裂隙承压含水层为主,其砂岩裂隙含水层的厚度由井田的浅部向深部增厚;含水层水压随其埋藏深度的增加而增高,呈线性关系,且富水性增强;12煤层底板隔水性能随着煤层埋藏深度的增加而减弱,且突水危险性增强.

Based on lithology and structural characteristics of aquifuge, the lithology-structural evaluation method which can evaluate the aquifuge water-resistance ability is provided. Considered the lithology and structural characteristics of aquifuge in water inrush coefficient, the water inrush risk evaluation classification of coal seam floor is proposed. Aiming at actual geological condition of No. 12 coal seam floor water inrush of Fangezhuang mine field in Kailuan, the sandstone fracture aquifer thickness of No. 12 coal seam floor and its characteristics, aquifuge lithology and distribution and fracture structure condition are analyzed systematically, and the floor water inrush risk is evaluated. The research results show that coal seam floor water-resistance ability depends on the lithology of aquifuge and the structure of fractures. With the increase of content and thickness of mudstone in the floor, the aquifuge water-resistance ability enhances and the water-resistance ability becomes better. With the increase of fracture develop-ment degree, the coal seam floor water-resistance ability decreases from intact structure and massive structure to cataclastic structure and loose structure, and the water-resistance ability of intact floor mudstone layer is obviously better than that of fractured floor mudstone layer.The source of water inrush from No. 12 coal seam floor is mainly about sandstone fracture confined aquifer between No. 12 coal seam and No. 14 coal seam. The thickness of sandstone fractured aquifer gets thicker gradually from the shallow to the depth of the mine field and the aquifer pressure adds following a linear correlation with the increase of its buried depth, and water abundance increases. The water-resistance ability of No. 12 coal seam floor becomes weaker with the increase of buried depth, and the water inrush risk becomes more obvious.