带压开采底板构造裂隙带活化导渗机制

发布时间：2019-01-26 16:36

【摘要】：随着煤矿延深开采，底板突水已成为威胁煤矿安全生产的最主要灾害之一，构造裂隙带突水是其主要表现形式，研究采掘过程中底板构造裂隙带活化渗流机制，对于矿井水害的预测和防治具有重要意义。为此，论文综合运用室内实验、理论分析及现场实测等方法，针对带压开采过程中的构造裂隙带活化突水通道形成机制及渗流突变规律进行了深入研究，取得如下成果：对岩石裂隙渗流的细观特征进行试验，分析岩石破坏过程中不同阶段渗透性变化及其与岩石内部微裂纹的演化关系，探讨岩石渗透性随变形的变化特点以及渗透系数应力之间的关联性，得出塑性软岩和脆性坚硬岩石在全应力应变过程中的变形规律及渗透性差异；根据脆性岩石的破坏机制与渗透系数的演化类比关系，结合岩石统计强度和重整化群理论，在岩石试样承载能力概率函数基础上推导出了预测岩石临界破坏点处应变的表达式。根据底板不同突水模式的力学共性特征，将底板突水划分为突水蓄势和突水失稳两个过程，并阐述各突水过程的基本力学特征，结合已有突水实例的统计结果，分析突水的发生条件、灾变特征及影响因素；通过现场原位压渗实测，获取煤系完整岩层及裂隙带岩体的平均阻渗强度，，研究底板岩体的阻渗特征，提出采用底板有效隔水层（单位厚度阻渗强度）评价断层带阻渗条件的方法。通过室内物理模拟试验，基于采用孔隙流裂隙流管道流的渗流组合类型来表示断层带渗流过程的思想，指出断层带中充填物颗粒的流失是断层突水量和渗流类型发生改变的基础；结合现场压渗试验结果获得了构造裂隙带渗透破坏是底板突水的前兆过程，构造裂隙带活化突水实质是底板岩体发生渗透破坏，也是底板水害防治的重要阶段。考虑断层破碎带中介质的不同力学性质及外界采掘扰动的影响，用突变理论建立断层活化失稳的非线性模型，推导出断层活化失稳的充要力学判据及突水临界压力；从非线性的角度将诱发断层活化突水的外界扰动条件分为临界微扰动和超前强扰动，分析煤层底板断层活化突水与外界采掘扰动条件的关联性，揭示外界扰动条件下的断层活化突水机理。论文最后将试验及理论成果应用于现场，检验断层带岩体阻渗强度评价方法及断层活化突变模型的适用性，为带压开采构造扰动底板突水危险性评价提供了理论依据。
[Abstract]:With the deep mining of coal mine, the water inrush from floor has become one of the most important disasters threatening the safety of coal mine production, and the water inrush of structural fissure zone is the main manifestation of it. The mechanism of activated seepage in the tectonic fissure zone of floor plate during mining is studied. It is of great significance for the prediction and prevention of mine water damage. In this paper, the mechanism of formation of activated water inrush passage in structural fissure zone and the law of seepage mutation in the process of mining with pressure are studied thoroughly by means of laboratory experiment, theoretical analysis and field measurement. The results are as follows: the microscopic characteristics of rock fissure seepage are tested, and the relationship between the permeability change in different stages of rock failure and the evolution of microcracks in rock is analyzed. The variation characteristics of rock permeability with deformation and the relationship between permeability coefficient stress are discussed. The deformation law and permeability difference between plastic soft rock and brittle hard rock in the process of full stress and strain are obtained. According to the relationship between the failure mechanism of brittle rock and the evolution analogy of permeability coefficient, combined with the statistical strength of rock and the theory of renormalization group, the expression of strain at critical failure point of rock is derived on the basis of probability function of bearing capacity of rock specimen. According to the general mechanical characteristics of different water inrush modes, the water inrush is divided into two processes: water inrush potential and water inrush instability. The basic mechanical characteristics of each water inrush process are expounded, and combined with the statistical results of existing water inrush examples. The occurrence conditions, catastrophic characteristics and influencing factors of water inrush were analyzed. The average impermeability strength of intact strata and fracture zone rock mass of coal measures is obtained by in-situ pressure seepage measurement, and the impermeability characteristics of floor rock mass are studied. This paper presents a method for evaluating the impermeability condition of fault zone by using effective water barrier layer (per unit thickness of impermeable strength) of bottom plate. Through the laboratory physical simulation test, based on the idea of adopting the seepage combination type of pore flow and fissure flow pipe flow to express the seepage process of fault zone, It is pointed out that the loss of filling particles in fault zone is the basis for the change of fault water inrush and seepage type. Combined with the results of the field pressure-seepage test, it is obtained that the seepage failure of the structural fracture zone is a precursor process of water inrush from the bottom plate, and the activated water inrush of the structural fissure zone is the seepage failure of the floor rock mass and the important stage of the prevention and control of the water hazard of the bottom plate. Considering the different mechanical properties of the medium in the fault fracture zone and the influence of the external mining disturbance, the nonlinear model of the fault activation instability is established by using the catastrophe theory, and the filling mechanics criterion and the critical pressure of water inrush are derived. From the nonlinear point of view, the external disturbance conditions of induced fault activation water inrush are divided into critical micro-disturbance and advanced strong disturbance, and the correlation between the induced fault activation water inrush and the external mining disturbance condition is analyzed. The mechanism of fault activation and water inrush under external disturbance is revealed. Finally, the test and theoretical results are applied to the field to test the applicability of the evaluation method of seepage resistance strength of rock mass in fault zone and the catastrophe model of fault activation, which provides a theoretical basis for the risk assessment of water inrush from disturbed bottom plate of structure with pressure mining.
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TD745

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