摘要
粗糙节理的隙宽分布不均匀是引起节理渗流出现曲折现象的主要原因。针对节理试件B01和B02,在获得节理的三维表面形貌并计算节理的三维空腔组合形貌后,分别进行室内渗流试验和Reynolds方程下的节理渗流数值模拟,得到节理中的曲折流径分布,在此基础上根据节理三维空腔组合形貌定义定量描述节理渗流曲折效应的平均曲折因子。在考虑节理表面粗糙性的立方定理修正经验公式的基础上,采用分析岩石渗透系数的等效沟槽模型对粗糙节理的渗流进行分析,推导得到考虑曲折效应的节理渗流计算公式,并根据节理试件B01的数值计算结果确定渗流计算公式中的待定常数。然后采用节理试件B02的数值计算结果对渗流计算公式的准确性进行验证,计算结果表明考虑节理渗流曲折效应的渗流计算公式可以较好地反映节理中的渗流情况。在此基础上,将根据本文渗流计算公式得到的节理试件渗流结果与渗流试验实测值及速宝玉经验公式计算结果进行比较,结果表明:考虑曲折效应的节理渗流计算公式渗流结果与实测值一致,而速宝玉经验公式过高地估计了节理的渗流量,进一步验证了节理渗流计算公式的准确性。
Uneven distribution of joint apertures mainly causes the tortuosity of flow through a rough joint. Taking two joint specimens B01 and B02 as research objects, laboratory flow tests and numerical simulations through the specimens are performed after scanning three-dimensional（3D） surface topography of joint. The tortuous streamlines of flow through a joint are derived from numerical simulations： and the tortuosity coefficient which quantitatively describes the tortuosity effect of flow through a joint is defined and calculated according to the 3D void composite topography. Then based on modified cubic law taking into account the roughness of joint surface, the new equation accounting for tortuosity effect for calculating flow volumetric rate through a joint is deduced by applying the equivalent channel model which is adopted to analyze the permeability of rock. The two constants A and B in the new equation are obtained by fitting the numerical simulation results of joint specimen B01. Then the flow rates of joint specimen B02 derived from the new equation and numerical simulations are compared with each other to validate the new equation. Furthermore, the flow volumetric rates of the two joint specimens derived from the new equation, SU Baoyu empirical method and laboratory flow experiments are compared with each other, which shows that the results obtained by the new equation agree well with experimental observations, while the SU Baoyu empirical method overestimates the flow rates, thus verifying the validity of the new equation.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2011年第12期2416-2425,共10页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(40972178
40472142)
