模拟不同节理粗糙度对单裂隙渗流的影响

在研究岩体裂隙间的渗流特性时,节理粗糙度会影响裂隙水流的渗流特性和路径,因此需要对粗糙表面进行恰当的描述。本文选取伸长率、最大起伏高度、最大起伏角和分维数4个参数刻画粗糙度。结合分维数的计算方法,选择当最大起伏高度为2.5mm、节理宽度为5mm时,随机生成4组直线和曲线节理边界。建立二维模型模拟发现,最大起伏角、伸长率和分维数是影响水流流速分布的敏感因素。在节理最高起伏处的下边界,流速值最大。此外,粗糙度的方向性对渗流影响较大。同等节理条件下,可发现沿水流方向,最大起伏高度的位置越靠后,越能抑制最大流速值,从而减小渗流破坏。最后,根据规则锯齿状的节理试验分析表明,在外力条件下,渗流量一定时,节理通道一旦发生改变,内部形成的漩涡便与水流的有效路径呈现负相关关系。

Simulating the influence of different joint roughness on single-fracture seepage

When studying the seepage characteristics between rock mass fractures,the joint roughness affects the seepage characteristics and the path of water flow,so the rough surface needs to be properly described.In this paper,4 parameters of the roughness profile index,the maximum tooth dip height,the maximum tooth dip angle and fractal dimension are selected to describe the roughness.Combined with the calculation method of fractal dimension,4 sets of straight line and curve joint boundaries are randomly generated when the maximum tooth dip height is 2.5mm and the joint width is 5mm.The simulation of the two-dimensional model found that the maximum tooth angle,the roughness profile index and fractal dimension are the sensitive factors affecting the flow velocity distribution.The flow velocity is the maximum at the lower boundary of the joint maximum fluctuation.In addition,the directionality of the roughness has a greater influence on the seepage.Under the same joint conditions,it can be found that the later the position of the maximum tooth dip height along the direction of flow is,the more the maximum flow velocity value can be suppressed,thereby reducing the seepage damage.Finally,according to the ruled jagged joint test analysis,under the external force condition,the seepage flow is constant,once the joint channel changes,the internal vortex is negatively correlated with the effective path of water flow.