物源组合对煤系断层破碎带渗透性的影响研究

发布时间：2018-03-09 13:16

本文选题：断层　切入点：破碎带　出处：《中国矿业大学》2017年博士论文　论文类型：学位论文

【摘要】：断层破碎带的渗透性是控制断层导水能力及其危害程度的决定因素。断层破碎带的物质组成与结构是决定自身渗透性的基础。断层破碎带物质主要由两盘地层破碎和结构重组后形成。由于岩性不同,破碎后岩块的内部裂隙分布、形态、粒度、化学成分等呈现出差异性。本文通过理论分析、室内试验及现场工程实例,研究煤系断层破碎带物源组合特征对其渗透性的影响,并取得了如下主要成果:(1)从宏观、细观和微观三个尺度研究了任楼煤矿F2断层及钱营孜煤矿DF200断层断层带的物质组成及渗透性的分带性特征。从宏观角度,结合破碎带内岩石破碎特征、充填及胶结特征及裂隙发育情况,发现物源特征及渗透性的变化与距断层面距离大小有着密切联系。从细观角度,通过室内崩解试验发现,断层带岩样饱水状态下崩解后主要可以分为完整型、裂解型及泥化型三类,并获得了水解后断层破碎带岩样的颗粒粒径分布特征。从微观角度观测发现,煤系破碎带内岩样往往含有较高含量的黏土矿物成分,黏土矿物集合体间的微观孔隙、裂隙对岩样的崩解起着重要作用。(2)对煤系不同岩性岩石进行了两次室内的单轴破碎试验,得到了不同岩性岩石的破碎特征及破碎后颗粒粒径的分布特征。不同岩性岩石破碎后,泥岩的破碎损失率最大,但泥岩破碎程度要弱于粉砂岩、细砂岩及石灰岩。对破碎后不同岩性颗粒粒径特征的统计发现,在两次破碎过程中泥岩破碎后形成碎裂岩的比例都要高于砂岩及石灰岩,同时破碎后各自的颗粒粒径特征也不同。(3)通过试验得到了小于1mm颗粒含量对破碎岩石的孔隙度n、渗透系数K、水力坡度值J的影响规律。发现了断层破碎带渗透性不完全取决于其孔隙度,主要是由颗粒级配决定。在孔隙度不变的情况下,破碎带内大颗粒(指不同配比组合中粒径最大的颗粒)所占比重越大,其渗透系数值K也越大。另外,黏土矿物的最终膨胀率越大,其对破碎岩体渗透性的弱化效果越明显。(4)根据理论分析及推导,解释了颗粒粒径及黏土矿物对断层破碎带渗透性的影响。建立了断层破碎带物源组合与受影响地层岩性厚度比及断距之间的概念模型,结合不同岩性的破碎损失率,得出了破碎带内物源组成的比例及断层破碎带内碎裂岩与砾岩比例。从而揭示了断层两盘不同岩性地层厚度比R、岩石破碎损失率ω及各岩性碎裂岩比例λ对断层破碎带内各岩性的总体混合比例、组成成分及颗粒粒径特征的控制作用。(5)现场实测和工程实例证明了断层破碎带内部物源组合对其渗透性的影响。结果表明:断层破碎带内泥岩含量越大,破碎带内细小颗粒含量也越多,使得内部孔隙、裂隙被充填而减小,从而减小了有效的渗流通道,增加了渗流的粘滞阻力及水头损失。另外小颗粒的“迁移”也容易造成充填、堵塞,从而降低断层破碎带的渗透性。
[Abstract]:The permeability of fracture zone is the decisive factor to control the water conductivity of fault and its damage degree. The material composition and structure of fault fracture zone are the basis of determining its own permeability. The material of fault fracture zone is mainly broken by two layers. Broken and restructured. Because of the different lithology, The distribution, morphology, granularity and chemical composition of the fractured rock block show differences. This paper studies the influence of the combination characteristics of material and source on the permeability of coal measure fault fracture zone by theoretical analysis, laboratory test and field engineering examples. The main achievements are as follows: (1) the material composition and permeability of the F _ 2 fault zone and the DF200 fault zone of Qianyingzi Coal Mine are studied from the macroscopic, meso-scale and microscopic scales. From the macroscopic point of view, the characteristics of the material composition and permeability of the F _ 2 fault zone and the DF200 fault zone in Qianyingzi Coal Mine are studied. According to the characteristics of rock fracture, filling and cementation, and the development of fractures, it is found that the variation of provenance and permeability is closely related to the distance from fault plane. The rock samples in the fault zone can be divided into three types: complete type, cracking type and gouging type. The particle size distribution characteristics of the rock samples in the fractured zone after hydrolysis are obtained. From the microscopic point of view, it is found that the rock samples in the fracture zone of the fault zone can be divided into three types. The rock samples in the fractured zone of coal measures often contain relatively high content of clay minerals. The micro pores and cracks between clay mineral aggregates play an important role in the disintegration of rock samples. The uniaxial crushing tests of different lithologic rocks of coal measures have been carried out twice in laboratory. The fragmentation characteristics and particle size distribution characteristics of different lithologic rocks are obtained. The fragmentation loss rate of mudstone is the largest, but the fragmentation degree of mudstone is weaker than that of siltstone. Statistics of particle size characteristics of different lithologic particles after crushing show that the ratio of fractured mudstone to clastic rock is higher than that of sandstone and limestone in the process of twice crushing. The effect of particle content less than 1 mm on the porosity, permeability coefficient K and hydraulic slope value J of broken rock was obtained by experiments. The permeability of fracture zone was found. Is not entirely dependent on its porosity, It is mainly determined by particle gradation. Under the condition of constant porosity, the larger the proportion of large particles (the largest particle in different ratio combinations), the larger the permeability coefficient K in the broken zone. The greater the final expansion ratio of clay minerals, the more obvious the weakening effect of clay mineral on the permeability of broken rock mass. The effects of particle size and clay minerals on the permeability of fracture zone are explained. A conceptual model between the combination of source material in fault fracture zone and the ratio of lithology thickness and fault spacing of affected strata is established, and the breakage loss rate of different lithology is combined. The ratio of material source composition in fracture zone and the ratio of cataclastic rock to conglomerate in fault fracture zone are obtained. Thus, it is revealed that the ratio of different lithologic strata thickness, rock breakage loss rate 蠅 and the ratio 位 of each lithologic cataclastic rock to fault are revealed. The total mixing ratio of each lithology in the fractured zone, The effect of composition and particle size characteristics on permeability has been proved by field measurements and engineering examples. The results show that the greater the mudstone content in the fracture zone is, the greater the content of mudstone in the fracture zone is. The more the content of fine particles in the broken zone is, the smaller the internal pores and fissures are, thus reducing the effective seepage passage, increasing the viscous resistance and head loss of seepage, and the "migration" of small particles can also easily lead to filling. Blockage, thereby reducing the permeability of the fracture zone.
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD745

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