【摘要】 为研究大尺度裂隙内部复杂的渗流规律,综合分析裂隙面粗糙度、初始裂隙宽度、剪切过程裂隙接触面积以及剪切碎屑对渗流的影响,提出一种考虑剪切接触与碎屑充填的裂隙渗流模型并开展多种工况下的数值实验研究。研究结果表明:当裂隙相对接触率低于15%时,等效水力宽度数值计算结果与理论计算结果基本吻合,当裂隙接触面积继续增大,两者计算结果出现较大偏差;当裂隙表面模型增加相同的分形维数时,渗流体积流量减小愈加明显;分形维数为2.4的裂隙模型接触率变化范围为19.3%～29.2%,但稳定体积流量仅为初始状态的0.20%,说明剪切过程裂隙接触面积对渗流的影响与其分布状态密切相关,其影响远大于仅改变裂隙接触面积的影响;渗流方向与剪切位移方向对渗流的影响同样是通过改变裂隙接触分布状态实现,优势导水通道对渗流规律的影响起主导作用;裂隙剪切过程所产生的岩石碎屑对渗流规律存在较大影响,出口流量稳定值分别为未考虑裂隙碎屑充填模型的27.1%和32.4%,且裂隙初始宽度越小,影响越显著。更多还原

【Abstract】 In order to study the complicated characteristics of seepage in large-scale fractures, the effects of fracture surface roughness, initial fracture width, fracture contact area in shearing process and clastic rocks on seepage were comprehensively analyzed. A fracture seepage model considering shearing contact area and clastic rocks was proposed and numerical experiments under various conditions were carried out. The results show that when the relative contact ratio of fractures is less than 15%, the numerical calculation model of equivalent hydraulic width is basically consistent with the theoretical calculation results; when the fracture contact area continues to increase, there is a big deviation between the calculation results of the two methods. When the fracture surface model increases the same fractal dimension, the decrease of seepage volume is more obvious. The contact rate of fracture model with fractal dimension2.4 varies from 19.3% to 29.2%, but the stable volume flow rate is only 0.20% of the initial state. The influence of fracture contact area and fluid movement direction on seepage in shearing process is closely related to the contact distribution, which is far greater than that of simple contact area changes. The formation of dominant conduit plays a leading role in the influence of seepage law. Clastic rocks produced by fracture shearing process have a great influence on seepage characteristics. The stable values of the outlet flow in the fracture filling model and the non-fracture filling model are 27.1% and 32.4%, respectively, and the smaller the initial width of the fracture, the more significant the effect will be.更多还原