三维应力下破碎煤岩样渗透特性试验研究

发布时间：2018-03-07 03:29

本文选题：破碎煤岩样　切入点：渗透特性　出处：《西安科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着煤炭开采深度的逐步延伸,煤岩体受采动影响发生破碎后形成堆积体。由于矿井深部堆积的煤岩体往往要承受较高的轴压、围压和孔隙水压,从而易引发矿井突水和采空区沉陷等事故。研究破碎煤岩体的渗流特性是防治矿井突水和采空区沉陷的基础课题。本文采用自主研发的破碎岩石三维渗流试验系统进行破碎煤岩样的渗流试验研究,该系统由三维渗透仪、液压泵、溢流阀以及围压液加载系统等组成,通过轴向位移法和稳态渗透法,研究不同渗透压、不同轴向位移和不同围压下级配粒径矸石和5种粒径破碎煤样的渗透特性,分析了粒径、轴向位移、轴向应力、围压与孔隙度等对其渗透性参量的影响,得到以下主要研究成果:(1)级配粒径矸石的孔隙度随着轴向应力或围压的增大,均呈现出减小的趋势;当围压增大时,渗透率逐渐减小,而非Darcy流β因子整体增大。(2)级配粒径矸石渗透率随着轴向应力的增大整体呈现减小趋势,非Darcy流β因子随着轴向应力的增加呈增大趋势,且两者之间的关系符合乘幂函数。(3)破碎煤样的渗透特性在三维应力下表现为二次拟合的现象更为显著;粒径越小,其在渗流过程中偏离线性拟合的现象越明显。孔隙度随着轴向位移或围压的增大而均呈现减小趋势,且围压与孔隙度之间可用对数拟合。(4)破碎煤样的渗透率随轴向位移或围压的增大均呈现出逐渐减小的趋势,随孔隙度?的增大整体呈现增大趋势。破碎煤样的非Darcy流β因子随着轴向位移或围压的增大均呈现出逐渐增大的趋势,而随着孔隙度的增大呈减小趋势。
[Abstract]:Along with the coal mining depth extending step by step, the coal and rock mass is broken by the mining movement, and then the accumulative body is formed. Because the coal and rock mass accumulated in the deep mine often have to bear higher axial pressure, confining pressure and pore water pressure, It is easy to cause accidents such as mine water inrush and goaf subsidence. Studying the seepage characteristics of broken coal and rock mass is the basic task of preventing mine water inrush and goaf subsidence. In this paper, the 3D seepage test system of broken rock is adopted. The percolation test of broken coal and rock samples, The system is composed of three dimensional osmometer, hydraulic pump, relief valve and confining pressure liquid loading system. The different osmotic pressures are studied by means of axial displacement method and steady state osmotic method. The permeability characteristics of coal samples with different axial displacement and different confining pressure are analyzed. The effects of particle size, axial displacement, axial stress, confining pressure and porosity on the permeability parameters are analyzed. The following main research results are obtained: the porosity of grained gangue decreases with the increase of axial stress or confining pressure, and the permeability decreases gradually with the increase of confining pressure. However, the permeability of gradation gangue decreased with the increase of axial stress, and the 尾 factor of non-#en1# flow increased with the increase of axial stress. The relationship between them is in accordance with the power function. 3) the permeability characteristics of broken coal samples are more obvious under the three dimensional stress, the smaller the particle size is, the more obvious the permeability is. The deviation from linear fitting is more obvious in the seepage process. The porosity decreases with the increase of axial displacement or confining pressure. The permeability of broken coal samples decreased gradually with the increase of axial displacement or confining pressure, and with the porosity, the permeability of broken coal samples decreased gradually with the increase of axial displacement or confining pressure, and the permeability of broken coal samples decreased gradually with the increase of axial displacement or confining pressure. The non Darcy flow 尾 factor of broken coal samples increased gradually with the increase of axial displacement or confining pressure, but decreased with the increase of porosity.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD311

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