CAJ | 학술논문

石灰岩层往往成为煤矿开采防水害的主要对象，且淮南老矿区也发生了多次底板灰岩层突水，为解决新区水压高、传统隔水层薄的问题，提出改造或直接利用底板石灰岩层相对隔水性实现带压安全开采的构想，选择地处煤田中西部南缘的新集二矿为现场，综合运用岩石成分、水化学成分、岩石力学指标测试和微孔隙结构、渗透性实验等室内实验和水文地质钻探、物探、现场试验等手段进行研究。结果表明：1)四周为断层所切割，顶部为第四系和推覆体变质岩覆盖，500 m埋深为界原地应力由浅部的张应力转变为压应力状态，深部岩层裂隙开启性差；2)水化学类型为Cl-Na型，矿化度大于1.5 g/L，岩层空隙处于沉淀充填状态；3)下组煤底板灰岩渗透性和富水性很差，可以看作相对隔水层，井下钻孔证实出水钻孔多靠近大型断裂，且出水量小而衰减快。首采面安全开采和第2个面的安全掘进证明下组煤底板灰岩为相对隔水层或稍加改造可以作为隔水关键层的结论是正确的。
석회암층왕왕성위매광개채방수해적주요대상，차회남로광구야발생료다차저판회암층돌수，위해결신구수압고、전통격수층박적문제，제출개조혹직접이용저판석회암층상대격수성실현대압안전개채적구상，선택지처매전중서부남연적신집이광위현장，종합운용암석성분、수화학성분、암석역학지표측시화미공극결구、삼투성실험등실내실험화수문지질찬탐、물탐、현장시험등수단진행연구。결과표명：1)사주위단층소절할，정부위제사계화추복체변질암복개，500 m매심위계원지응력유천부적장응력전변위압응력상태，심부암층렬극개계성차；2)수화학류형위Cl-Na형，광화도대우1.5 g/L，암층공극처우침정충전상태；3)하조매저판회암삼투성화부수성흔차，가이간작상대격수층，정하찬공증실출수찬공다고근대형단렬，차출수량소이쇠감쾌。수채면안전개채화제2개면적안전굴진증명하조매저판회암위상대격수층혹초가개조가이작위격수관건층적결론시정학적。
Limestone layer is often regarded as the main cause of coal mine water damage and water inrush events, which actually happened more than once in old mining area in Huainan. A conception has been put forward that reconstruction or direct utility of relative impermeability of floor limestone layer can solve the problem of high water pressure and thin aquiclude and ensure safety during mining under pressure. Xinji Second coal mine has been selected as the research field which is located in the southern edge of the midwest coalfields and comprehensive methods have been used to research including the index test of rock composition, chemical action of compositions of groundwater, and rock mechanic, micro-pore structure, the laboratory experiment about permeability and the field test about hydrogeolog-ic drilling, geophysical prospecting. The research results show that:1) Xinji Second Coal Mine is cut by faults all around, with the top covered by quaternary system and metamorphic nappe. The in-situ stress changes from tensile in the shallow part to compressive at a depth under 500 m. The crack of deep rock layer is not easy to open up. 2) The hydrochemical type is Cl-Na. Salinity is greater than 1.5 g/L and rock voids is filled by the precipitation. 3) The permeability and water rich property of limestone floor is poor, so it can be regarded as aquiclude. It is confirmed that inrush boreholes mostly close to the large faults and water yield is small and disappear quickly through boreholes in the coal mine. Safe mining of the first coal mining face and safety tunneling of the second working face testify the result that the floor limestone layer is aquiclude and the water-resisting key strata after reconstruct is correct.