【作者】 刘树才；

【导师】 缪协兴；

【作者基本信息】 中国矿业大学 ， 工程力学， 2008， 博士

【摘要】 煤层底板突水是煤矿五大动力灾害之一,研究开采过程中底板的变形、渗流规律,探索突水机制和防治技术,仍是今后煤矿安全生产的重要任务。本文从试验、理论、数值分析和工程实践等方面对煤层底板突水机制、裂隙演化的连续探测技术和突水防治技术进行研究。主要研究内容包括(1)测试了4种岩石(砂岩、灰岩、泥岩和煤)试样在破坏过程中的渗透特性。定义了渗流稳定性指数,简单地分析了非Darcy流ββ因子和加速度系数出现负值的原因。(2)建立了一种岩层变形—渗流耦合动力学模型,给出了变形—渗流耦合响应显式快速Lagrange分析法循环框图。在建立本构关系时,定义了描述材料变形状态的函数,考虑了两种破坏形式,即拉伸破坏和剪切屈服,并考虑了变形状态之间的转换。(3)采用“半耦合”的方法,计算了龙固煤矿屯头系21煤层21201回采工作面底板的突水因数,并在此基础上运用时变边界系统动力学的观点分析了煤层底板的突水机理。认为突水的发生与否取决于煤层底板边界(包括弹性区、塑性区、破裂区和破碎区之间的界面)的变化过程,发生突水需要具备两个条件,一是导水通道的形成,二是渗透特性、含水层压力满足一定关系。当突水因数大于1时,发生突水。(4)采用小四极法测定了灰岩、泥岩和砂岩在渗水和不渗水条件下应力—应变全程电阻率的变化,归纳出应变—电阻率的曲线的几种形式。在此基础上,分析了煤层底板岩层破坏机理及电性变化规律。(5)利用3D EarthImager软件对底板破坏带动态地电模型进行正演模拟,得到五沟煤矿煤层底板破坏带在工作面推进不同时期的视电阻率等值线图。依据并行电法测量的思想,设计了不同现场条件下煤矿底板破坏裂隙带动态监测系统,提出了系统设计原则和技术要求,为现场实际工作提供了参考。(6)将试验和理论研究成果应用于龙固煤矿的工作面底板突水综合防治及安徽五沟煤矿底板破坏裂隙带的动态监测。通过对龙固煤矿的工作面底板实施注浆加固,并改进采煤工艺以减小采动对底板的破坏深度,实现了安全回采。取得了明显的技术经济效益和社会效益。安徽煤矿底板破坏裂隙带的动态监测效果表明,采用电阻率法用于底板破坏裂隙带的探测监测效果比较明显,能显示出底板在回采过程中变化破坏情况,有利于底板水情的监测和突水预防措施的制订。更多还原

【Abstract】 Water inrush from Coal Seam Floor(CSF)is one of the five severe disasters in coal mines, and it is a main mission in the future to study the behaviors in the deformation of CSF and Seepage flow in CSF, and to uncover the mechanism of water inrush from CSF, and to develop the technique for prevention and cure of water inrush, and to realize the safety in coal mining. In the current thesis, the mechanism of water inrush from CSF, the technique for continuous survey of fractures in CSF and the prevention and cure of water inrush are systematically studied from several respects,including test, theoretical and numerical analysis, and engineering practices. The main subjects involve as follows:(1) The permeability parameters of four kinds of rock are measured by specimens which go through a total failure process. An index, namely seepage stability index, is defined. The reason why the non-Darcy flowβfactor and the acceleration coefficient may be negative is analyzed.(2) A dynamical model which describes the interaction between the deformation of a stratum and the seepage flow of water in the stratum is established. A Fast Lagrangian Arithmetic for calculation of Response of the Model is presented. Two kinds of failure of stratum, i.e., the submit induced by shear, and the failure induced by tension, were considered in the construction of constitutive relations. A function which describes the state of stratum at a point is defined. The switch among the states is also considered.(3)“Semi-coupling”method is used to calculate the water-inrush-factor (WIF) of the floor of Tuntou 21st Coal Seam around the 21201 waking face. The mechanism for water inrush from CSF is explained by using Dynamics of Systems with Variable Boundaries. It holds that whether water inrush takes place is decided by the change process of boundaries, including the interfaces among the elastic zone, plastic zone, fractured zone and broken zone. Water inrush will take place when two conditions are satisfied, the first is that the formation of passage for water to flow, the second is that the permeability parameters and pressures within the aquifer concerns a certain condition. When the water-inrush-factor is great than one, water inrush from CSF will follow.(4) The electrical resistivity of specimens of mudstone, sandstone and limestone are measured in the total stress-strain process. Several types of stress, strain—electrical resistivity curve are summarized. Based on what mentioned above, a ground-electricity model for forward simulation of the distribution of electrical resistivity is presented; the mechanism of the failure of CSF and the law that electrical resistivity changes as the permeability parameters are uncovered.(5) A software, 3D EarthImager, is used to forward simulate the fractured zone in CSF and the change of apparent resistivity of the zone as the working face advances on. On the principle of parallel electrical survey, a system of successively monitoring the fractured zone in CSF is designed. The technical specifications and requirements for the monitoring system are presented. The monitoring system can provide efficient data for the engineering practice in coal mining.(6) The results in both test and theoretical study have been used to the integrated control of water inrush from CSF in Longgu Coal Mining and to the successive monitoring of the fractured zone of CSF in Wugou Coal Mining, Anhui.Based on the integrated geophysical exploration to the floor of Tuntou 21st Coal Seam arousing the 21201 Waking Face, a series of control measurements to prevent and cure water inrush have been formulated, such as injection grouting to the CSF, improving the technique of coal mining. By these means, the depth of fractured zone in CSF has decreased, and the realization of safe mining comes being. Economic and social benefits have been made observably.The results of successive monitoring of the fractured zone in CSF in Wugou Coal Mine show that the change of the fractured zone is very evident. Electrical resistivity method can be used to monitor the water situation in CSF and be use a supplementary means in the prevention and cure water inrush.更多还原