裂隙茅口灰岩渗流—应力耦合试验研究
发布时间：2019-06-08 06:33
【摘要】：裂隙岩体是自然界中广泛存在的一种具有灾害隐患的岩体,其渗流失稳是导致岩体工程破坏,甚至大型地质灾害的重要原因。目前,对于裂隙岩体渗透特性的研究,其室内试验研究是不可或缺的重要技术手段,本文基于茅口灰岩展开裂隙岩体渗流-应力耦合试验的研究。试验岩样取至湖南宁乡煤炭坝,按国际岩石力学推荐标准加工成尺寸为Φ50×100mm的试件。首先,在RYL-600剪切流变仪上对完好岩样进行劈裂试验,获取裂隙茅口灰岩样,并取其中岩样进行循环加卸载试验;其次,取裂隙岩样在M T S 8 1 5岩石力学试验系统上进行渗流-应力耦合试验,主要对裂隙岩体渗流-应力耦合试验特性进行研究。本文结合以上试验进行研究并得到了以下相关结论:(1)本文首先完成了对于裂隙岩样在相等最大法向应力作用下的循环加卸载试验,结果表明:裂隙法向闭合量虽然随着循环加载次数的增加而增大,但最终裂隙并未完全闭合,而是有一定的裂隙张开度,这就是所谓的裂隙残余闭合量。(2)针对同一批次裂隙岩样进行了同一轴压不同围压作用下的渗流-应力耦合试验,结果表明:1)同一轴压作用下,渗透系数与围压呈负幂律关系,随围压增加不断变小;体积应力、渗透系数和孔隙压三者能很好的满足指数规律关系,同一孔隙压作用下,随体积增加渗透不断减少;2)同一荷载作用下岩样裂隙张开度大的渗透系数较张开度小的大;3)茅口灰岩的裂隙流不满足Darcy流,具有非D a r c y效应,且同一轴压作用下,随着围压的增大,非D a r c y效应不断增强。4)岩样同一荷载作用下的非Darcy流渗透率较Darcy流的大;5)岩样渗流过程中环向位移与孔隙压差具有正相关的关系,孔隙压差发生较大变化处,环向位移也会发生较大的变化;6)茅口灰岩岩样的裂隙流满足沟槽模型,试验计算渗透系数值与理论计算值基本相符。(3)使用MATLAB软件对渗流试验岩样端面裂隙分布进行分形维数计算,并与渗流试验结果进行对比,结果表明相近隙宽下,裂隙分形维数越大,其渗透系数也越高。
[Abstract]:Fracture rock mass is a kind of rock mass with hidden danger in nature, and its seepage and loss stability is an important cause of rock mass engineering damage and even large geological disasters. At present, the laboratory test research on the permeability characteristics of fracture rock mass is an indispensable and important technical means. Based on the study of seepage-stress coupling test of fracture rock mass carried out by Maokou limestone, this paper is based on the study of seepage-stress coupling test of fracture rock mass. The test rock samples were taken to Ningxiang Coal Dam in Hunan Province and machined into 桅 50 脳 100mm specimens according to the international recommended standard of rock mechanics. Firstly, the split test of intact rock sample was carried out on RYL-600 shear rheometer, and the limestone sample of fissured Maokou was obtained, and the rock sample was taken for cyclic loading and unloading test. Secondly, the seepage-stress coupling test of fracture rock sample is carried out on M T S 815 rock mechanics test system, and the characteristics of seepage-stress coupling test of fracture rock mass are mainly studied. In this paper, combined with the above tests, the following conclusions are obtained: (1) in this paper, the cyclic loading and unloading test of fracture rock samples under the action of equal maximum normal stress is completed. The results show that although the normal closure of cracks increases with the increase of cyclic loading times, the cracks are not completely closed, but there is a certain degree of fracture opening. This is the so-called residual fracture closure. (2) the seepage-stress coupling tests under the same axial pressure and different confining pressure are carried out for the same batch of fracture rock samples. The results show that: 1) under the same axial compression, There is a negative power law relationship between permeability coefficient and confining pressure, which decreases with the increase of confining pressure. The relationship between volume stress, permeability coefficient and pore pressure can meet the exponential law very well. Under the same pore pressure, the permeability decreases with the increase of volume. 2) the permeability coefficient of rock sample fracture opening is larger than that of rock sample fracture under the same load. 3) the fracture flow of Maokou limestone does not satisfy Darcy flow and has non-Darcy effect, and under the same axial pressure, with the increase of confining pressure, The non-Darcy effect is increasing. 4) the permeability of non-Darcy flow under the same load is larger than that of Darcy flow. 5) there is a positive correlation between circumferential displacement and pore pressure difference in the seepage process of rock samples. When the pore pressure difference changes greatly, the circumferential displacement will also change greatly. 6) the fracture flow of Maokou limestone sample satisfies the trench model, and the calculated permeability coefficient is in good agreement with the theoretical value. (3) the fractal dimension of fracture distribution at the end face of seepage test rock sample is calculated by MATLAB software. Compared with the seepage test results, the results show that the larger the fractal dimension of the fracture is, the higher the permeability coefficient is.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45
本文编号：2495075
[Abstract]:Fracture rock mass is a kind of rock mass with hidden danger in nature, and its seepage and loss stability is an important cause of rock mass engineering damage and even large geological disasters. At present, the laboratory test research on the permeability characteristics of fracture rock mass is an indispensable and important technical means. Based on the study of seepage-stress coupling test of fracture rock mass carried out by Maokou limestone, this paper is based on the study of seepage-stress coupling test of fracture rock mass. The test rock samples were taken to Ningxiang Coal Dam in Hunan Province and machined into 桅 50 脳 100mm specimens according to the international recommended standard of rock mechanics. Firstly, the split test of intact rock sample was carried out on RYL-600 shear rheometer, and the limestone sample of fissured Maokou was obtained, and the rock sample was taken for cyclic loading and unloading test. Secondly, the seepage-stress coupling test of fracture rock sample is carried out on M T S 815 rock mechanics test system, and the characteristics of seepage-stress coupling test of fracture rock mass are mainly studied. In this paper, combined with the above tests, the following conclusions are obtained: (1) in this paper, the cyclic loading and unloading test of fracture rock samples under the action of equal maximum normal stress is completed. The results show that although the normal closure of cracks increases with the increase of cyclic loading times, the cracks are not completely closed, but there is a certain degree of fracture opening. This is the so-called residual fracture closure. (2) the seepage-stress coupling tests under the same axial pressure and different confining pressure are carried out for the same batch of fracture rock samples. The results show that: 1) under the same axial compression, There is a negative power law relationship between permeability coefficient and confining pressure, which decreases with the increase of confining pressure. The relationship between volume stress, permeability coefficient and pore pressure can meet the exponential law very well. Under the same pore pressure, the permeability decreases with the increase of volume. 2) the permeability coefficient of rock sample fracture opening is larger than that of rock sample fracture under the same load. 3) the fracture flow of Maokou limestone does not satisfy Darcy flow and has non-Darcy effect, and under the same axial pressure, with the increase of confining pressure, The non-Darcy effect is increasing. 4) the permeability of non-Darcy flow under the same load is larger than that of Darcy flow. 5) there is a positive correlation between circumferential displacement and pore pressure difference in the seepage process of rock samples. When the pore pressure difference changes greatly, the circumferential displacement will also change greatly. 6) the fracture flow of Maokou limestone sample satisfies the trench model, and the calculated permeability coefficient is in good agreement with the theoretical value. (3) the fractal dimension of fracture distribution at the end face of seepage test rock sample is calculated by MATLAB software. Compared with the seepage test results, the results show that the larger the fractal dimension of the fracture is, the higher the permeability coefficient is.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45
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相关期刊论文 前2条
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2 李培超,孔祥言,卢德唐;饱和多孔介质流固耦合渗流的数学模型[J];水动力学研究与进展(A辑);2003年04期
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