【作者】 郑纲；

【导师】 刘玉海； 门玉明；

【作者基本信息】 长安大学 ， 地质工程， 2004， 博士

【摘要】 华北石炭二迭系煤田是我国重要的产煤区之一，其下组煤位于含水丰富的奥灰含水层或太原群灰岩含水层以上，中间隔水层厚约30～100米，经常发生底板灰岩突水。 由于煤矿底板突水是在矿井开发中一种严重的地质灾害现象，因而受到国内外的广泛重视，通过研究人们认识到突水是可以预测预报的，因为发生突水的物质基础和物理基础是可以被认识的。鉴于突水直接影响到煤矿的生产安全对底板突水机理的研究及突水预测预报技术研究成为承压水上采煤的关键技术。本文分两大部分对底板突水的机理、突水预测预报的理论基础、具体的突水预测预报技术进行理论和应用研究。文中第一部分根据底板突水的机理设计了岩体水力学实验，对岩体裂隙的三轴应力渗透规律进行了研究，指出岩体裂隙突水时，岩体裂隙的渗透系数与裂隙正应力不是负指数关系，渗透系数有突然增大的现象。并利用岩石断裂力学理论对此现象进行了解释，指出在岩体应力和水压力的作用下，岩体裂隙发生拉-张型扩展(K_Ⅰ型)是裂隙渗透系数突然增大的关键原因。沿裂隙发生剪切(K_Ⅱ型)扩展，使充填物微观结构破坏而增强空隙度和渗透性，则对突水的贡献是次要的。由此推论，煤层底板突水主要是由于底板裂隙发生拉-张型扩展，继而在水压力的作用下沿裂隙发生管涌现象而造成的。在分析煤矿底板突水地质背景的基础上，指出利用线弹性断裂力学对底板突水进行分析是合适的，通过研究确定了底板突水的断裂力学标准。具体分析了构造应力场、工程应力、地下水等对底板裂隙应力强度因子的影响，从断裂力学的角度分析各种因素对底板突水的影响。 利用裂隙的亚临界扩展理论对底板滞后突水现象进行了分析。裂隙中的粘土充填物在地下水物理、化学的作用下，力学性能不断弱化，使岩体裂隙的临界应力强度因子不断降低，裂隙扩展具有时间效应，导致底板裂隙的滞后突水。 在对水压致裂技术进行断裂力学分析的基础上，推导了计算岩体裂隙临界应力强度因子的计算公式，确定了用水压致裂技术测定临界应力强度因子的方法，为利用岩石断裂力学标准进行突水判别奠定了理论和实验基础。 文中介绍了板壳断裂力学理论Kirchhoff及Reissner弯曲断裂理论。板壳承受横向载荷，除了有面内位移外，还存在面外位移。板壳内的应力应变场沿厚度方向变化。Rei Ssner弯曲断裂理论考虑了板壳的横向剪切变形和板的厚度效应，更适合于采煤工作面底板的模拟。介绍了Rei ssner裂纹应力强度因子的计算方法，并通过简单模型计算分析了板边长、板厚度、水压对应力强度因子的影响，证明板厚度、水压对应力强度因子的影响巨大。 应用板壳断裂力学的方法分析工作面底板岩体在工程荷载的作用下引起裂隙扩展而导致的突水问题，为分析底板岩体的突水问题提供了一条新的途径。 论文第二部分结合东庞矿9103工作面的带压开采，研究了底板工作面斜长的确定方法;利用水压致裂技术求得了底板临界应力强度因子，结合工作面的实际水文地质工程地质条件研究了底板突水前兆实时监测技术，监测的项目包括应力、应变水压、水温，对9103工作面进行了21天的监测，利用第一部分的研究成果对监测数据处理，计算了底板裂隙应力强度因子，运用断裂力学突水判别标准，判断9103工作面不会突水，9103工作面实际回采结果与此相符。更多还原

【Abstract】 The carboniferous and Permian coal field is a important coal field in china .The substrate coal bed is on the top of the Ordovician and carboniferous limestone aquifers .the a quatard between the aquifer and the coal is about 30-60meters thick .So floor water bursting occurs usually.The floor water bursting is a geology hazard in coal mines in the east of china .But the water bursting can be predicted ,because the physical mechanism of water bursting can be studied . So the research on the water bursting mechanism and forecasting technique become the key technique of coal mining on top of the high pressure aquifer . In the dissertation the water bursting mechanism, water bursting theory and predicting technique are researched .In the first part of the dissertation, the rock -hydraulic experiment is devised according to water bursting essence, and the stress-permeability under triaxial compression is studied , which indicates that the permeability coefficient is inversely proportional to the virtual direct stress ,and the permeability coefficient changes suddenly on some conditions .The phenomenon is explained according to the fracture mechanism ,which indicates the rock crevice stretches and spreads under the rock stress and hydraulic pressure .So the rock crevice permeability increases suddenly .The shearing spreading along the crevice which destruct the microstucture and increase the permeability is subordinate .It is pointed that analyzing the floor water bursting according to the fracture mechanism is adaptable when the geology condition and the fracture mechanic criterion of water bursting is decided .The influence of the tectonic stress field .engineering stress and groundwater to the crevice stress intensity factors are analyzed. The phenomenon of the lagging water bursting is explained applying crevice inferior critical spreading .The mechanic capability of the crevice clay filling falls because the physiology and chemistry of the groundwater,which lags the crevice spreading and leads to the lagging floor water bursting.On the basis of explaining hydraulic fracture technique applying fracture mechanics theory ,the computation equation of the critical stress intensity factor is deduced .So the testing method is obtained according to the theory, which lay a foundation of theory and experiments for distinguishing water bursting applying fracture theory.The Kirchhoff and Reissner board bending fracture theory is introduced in the dissertation .The board endure transverse load ,which produce inner and outer displacement .The stress and strain in the board changes in the direction of thickness .Not only the board transverse shearing distortion but also the thickness is considered in Reissner board bending fracture theory .So Reissner theory is adapted to simulate the mining face floor .the computation of the crevice stress intensity factor is studied. The influence of the board width ,thickness and sustaining condition to the stress intensity factor is analyzed by ordinary model computation .the computation indicates the board thickness ,water pressure exert a tremendous influence to the stress intensity factor. In the second part of the dissertation, the delimiting method of the stope width mining on high pressure aquifer is decided for the example of 9103 stope in Dong Pang Coal Mine .The critical stress intensity factor is tested applying the hydraulic fracture technique .The technique of monitoring face floor water bursting indications is researched on the basis of studying the practical hydrogeology and engineering geology condition .The 9103 stope is monitored for 21 days .The monitoring data is analyzed applying the Reissner board bending fracture theory ,and the floor stress intensity factor is computed .Applying the floor water bursting criterion of fracture mechanics , it is concluded that the stope water bursting will not arise .The mining practice of the stope proves the conclusion right.更多还原