隧道裂隙岩体渗透系数试验研究

发布时间：2018-01-16 11:46

  本文关键词：隧道裂隙岩体渗透系数试验研究　出处：《石家庄铁道大学》2015年硕士论文　论文类型：学位论文

  更多相关文章： 裂隙岩体 单裂隙 垂直交叉裂隙 渗流与应力耦合 渗透系数 三轴渗透试验

【摘要】：采用巴西劈裂生成单裂隙、垂直交叉裂隙,模拟隧道内灰岩的单一、交叉张性裂隙,在岩石多功能试验机上开展单裂隙、垂直交叉裂隙围岩渗流与应力耦合、裂隙岩样渗透系数与裂隙宽度、面积、粗糙度系数关系规律三轴试验研究,主要研究了试件轴压、围压和水压对裂隙渗透系数的影响;采用数值拟合方法给出了不同应力条件下单裂隙、垂直交叉裂隙渗透系数计算公式及裂隙渗透系数与裂隙特征的关系曲线,为裂隙围岩隧道渗流场特征分析奠定基础,试验主要成果:(1)试验中采用了裂隙面图像处理的方法(Matlab图像分析-AutoCAD图像处理)对裂隙宽度测量方法进行了改进,取得了较为精确的裂隙宽度试验数据。(2)试验中采用了自制纵剖仪裂隙图像描绘,并与标准粗糙度区相对比的方法对裂隙粗糙度系数的测量方法进行了改进。(3)在轴向应力、水压力恒定的情况下围压增大,单裂隙的渗透系数与围压满足乘幂关系,而垂直交叉裂隙的渗透系数与围压满足对数关系。(4)单裂隙和垂直交叉裂隙,在围压、水压力恒定时,增大轴向应力,渗透系数均与轴向应力呈正比线性关系;轴向应力增加导致的岩样径向鼓效应是影响裂隙渗透系数的主导因素;在围压、轴向应力恒定时,裂隙渗透系数与水压力呈正比线性关系。裂隙开度随着围压的增加而减小,但围压增加到一定程度后,会逐渐趋于稳定,这是因为围压不能使裂隙完全闭合,裂隙渗流依然存在,且渗透系数远大于无裂隙岩体的渗透系数。(5)单裂隙或垂直交叉裂隙的渗透系数与裂隙面积成n次方关系。(6)在单裂隙粗糙度系数9,垂直交叉粗糙度系数数10时,渗透系数与裂隙面积的关系由二次函数过渡到三次函数。(7)数值拟合出了渗透系数与单裂隙粗糙度系数(≤9)及端面面积之间的函数关系式。
[Abstract]:The single fracture and vertical cross fissure in Brazil are adopted to simulate the single and cross tensile fracture of limestone in tunnel. The single fracture is developed on the multifunctional rock testing machine and the seepage and stress coupling of the surrounding rock with vertical cross fracture is carried out. The relationship between fracture permeability coefficient and fracture width, area and roughness coefficient is studied by triaxial test. The influence of axial pressure, confining pressure and water pressure on fracture permeability coefficient is studied. The numerical fitting method is used to give the formula for calculating the permeability coefficient of vertical cross fractures and the relationship between fracture permeability coefficient and fracture characteristics under different stress conditions. It lays a foundation for the analysis of seepage field characteristics of fractured surrounding rock tunnel. In the experiment, the image processing method of fracture surface is used to improve the measuring method of crack width by using Matlab image analysis and AutoCAD image processing. A more accurate fracture width test data is obtained. The self-made longitudinal profile instrument is used to depict the fracture image in the test. The measurement method of fracture roughness coefficient is improved by comparing with the method of standard roughness zone. The confining pressure increases under the condition of constant axial stress and constant water pressure. The permeability coefficient and confining pressure of single fracture satisfy the power relation, while the permeability coefficient and confining pressure of vertical cross fracture satisfy logarithmic relation. 4) when the confining pressure and water pressure are constant, the permeability coefficient of single fracture and vertical cross fissure satisfies logarithmic relation. When the axial stress is increased, the permeability coefficient is proportional to the axial stress. The radial bulging effect of rock samples caused by the increase of axial stress is the dominant factor affecting the permeability coefficient of fractures. When the confining pressure and axial stress are constant, the fracture permeability coefficient is proportional to the water pressure. The crack opening decreases with the increase of confining pressure, but when the confining pressure increases to a certain extent, it tends to stabilize gradually. This is because the confining pressure can not make the fracture complete closure, fracture seepage still exists. And the permeability coefficient is much larger than the permeability coefficient of rock mass without fracture. 5) the relation between permeability coefficient of single crack or vertical cross crack and fracture area is n ~ (th). (6) the roughness coefficient of single fracture is 9. The vertical cross roughness coefficient is 10:00. The relationship between permeability coefficient and fracture area is transformed from quadratic function to cubic function. The functional relationship between permeability coefficient and roughness coefficient of single fracture (鈮，

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