裂隙交叉联接对采动岩体中流体流动特性的影响研究

Effect of fractures cross connection on fluid flow characteristics of mining-induced rock

基于立方定律推导了交叉联接方式的流量计算方法,讨论得出了该方法与实测结果存在偏差的主因:过量压力降损耗.定义了过量压力降损耗系数,分析了过量压力降损耗系数的变化规律.结果表明:影响交叉裂隙的过量压力降损耗的因素有:交叉角度、裂隙隙宽及雷诺数,其中雷诺数对过量压力降损耗的影响最大;过量压力降损耗系数与雷诺数近似成二次下降的关系;交叉裂隙中流体的偏流及交汇只是表象,裂隙交叉处的流动收缩或者扩张效应才是过量压力降损耗产生的真正机制.在此基础上得到了交叉裂隙的准确流量计算公式,并探讨了该公式在实际裂隙网络中的简化应用方法.

By using Cubic law,the flow calculation method of cross connection is deduced.Excess pressure loss is found out to be the principal cause of its deviation from the measured result.Excess pressure loss coefficient is defined;the change of excess pressure loss coefficient is analyzed.Results show that the factors effecting excess pressure loss of cross fractures are cross angle,fracture aperture and Reynolds number,among which the Reynolds number has the largest impact.The excess pressure loss coefficient decreases squarely with Reynolds number.Flow contraction and expansion in cross fractures,rather than bias flow and intersection,turns out to be the real mechanism that causes excess pressure loss.Accordingly,an accurate flow formula for cross fracture is build,and its application with simplified method for actual fracture network is discussed.