高应力、高水压下深部采动断裂突水的水-岩相互作用研究

The coal mines that the exploitation transfers into the deep stratum are threaten by the deep high pressure confined karst water. The most water inrushes have been occurred because of deep faults. And the deep faults that were impervious in the original geological condition are induced by the deep mining and the water bursts through the activated fissures of deep faults. The deep faults, which are in the field of high geostress, induced by mining are effected by the high temperature(30-50℃), high degree of mineralization(3000-5000mg/L) and high pressure(6-12MPa) water. The mechanism of deep fault water inrush is not different from the fault induced by the shallow mining. The critical evaluation of water inrush from high pressure karst water under the coal floor in deep coal mine is becoming increasingly seriously. This subject develops the study of water-rock interaction of water inrush through deep mining-induced fault under the action of high stress and water pressure. The key scientific problems of "mining disturbance" and "water-rock interaction" are considered. On the basic study of the fault rock water-rock interaction geological environment type, the experimental study, theoretical analysis and correlation model about the mechanics, permeability and structural changes of deep fault rock will be carried out in the condition of the action of high stress, high osmotic pressure, water chemistry and mine pressure. The study of the above issue will have theoretical significance and engineering application value.

我国转入深部开采的华北型煤田受到深部高承压甚至是超高承压（大于10MPa）岩溶水威胁。煤层开采底板突水绝大多数是与断裂有着直接关系，而且大多数断裂突水是原始地质条件下的非导水断层在采动影响下发生突水。深部开采中，处于高地应力场中受矿压扰动的断层同时受到来自深部高温（30-40℃）、高矿化度（3000-5000mg/L）和高渗透压（6-12MPa）岩溶水的作用，突水机理和特征与浅部不同。深矿井深部煤层开采底板高压岩溶水突水危害隐患不断增加。本课题开展高应力、高压水作用下深部采动断裂突水的水-岩相互作用研究，重点考虑"采矿扰动"和"水-岩相互作用"这2个关键科学问题，在断层岩水-岩接触地质环境类型研究基础上，进行高应力、高渗压、水化学作用和矿压影响下深部断层岩水-岩相互作用力学性、渗透性及断层岩结构变化实验研究、理论分析和相关模型建立等研究，具有重要的学科基础理论意义和实际的工程应用价值。

深部开采中，处于高地应力场中受矿压扰动的断层同时受到来自深部高温、高矿化度和高渗透压岩溶水的作用，突水危害隐患不断增加。本课题重点考虑“采矿扰动”和“水-岩相互作用”关键科学问题，主要内容、结果和关键数据如下：.1）依据钻孔冲洗液消耗量、抽（放）水试验等首次揭示了兖州煤田富水性较强区域为C5、C7背斜和C6向斜、C8向斜，以及杏行背斜、皇甫断层和马家楼断层一带。.2）兖州煤田中奥陶统第6段厚度65.81 - 126.75m，第5段厚度104.75 - 127.3m；第6段的钻孔单位涌水量为0.587 ~ 3.502L/(s.m)，第5段的为2.488~8.721 L/(s.m)，对深部煤层开采有威胁的是奥灰含水层第6段。.3）借助曲率法和分形理论，对兖州煤田构造复杂程度进行了量化研究。曲率大于0.09或容量维值大于0.25时，认为该区域含水层富水性较强。当SO42-离子浓度高于1700-1800mg/L时，可以认为含水层富水性较弱。.4）桃园煤矿陷落柱突水机理研究表明：突水第1阶段由于采掘和奥灰高水压作用，陷落柱为渗流阶段；突水第2阶段柱体的细颗粒物质被水流带出，变成突水裂隙；突水第3阶段柱体的大颗粒甚至其中填充的石块被带出，呈现管道流特征。基于建立的解析力学模型计算得到：发生突水的水压力的极限值为4.7 MPa。.5）模拟了高地应力条件下近断层煤层反复采动过程，对比分析了初次采动和第二次采动时围岩竖向位移、竖向应力和塑性区分布规律；利用塑性区分布范围是否与含水断层接触判断煤层底板是否突水，并得到了工作面发生底板突水时的临界突水距离。.6）设计高承压水上断层突水正交试验进行对比研究，获取了渗透水压、粘性土含量和孔隙比对断层模型突水能力以及涌水量大小影响的主次顺序；分析了初始涌水量值与断层模型中粘性土含量、渗透水压和孔隙比的函数关系；提出了涌水量的计算公式。.研究结果在深部岩溶富水规律、深部采动围岩应力特征和构造破碎带突水机理方面的研究具有一定的新意，可为我国深部煤炭资源开发水害防治提供基础研究依据和参考。