岩体裂隙面粗糙度对其渗流特性的影响研究

发布时间：2019-01-08 07:51

【摘要】：为了研究岩体裂隙面的粗糙程度与渗流机制间的相互关系,将裂隙沿长度方向均匀分割成若干段,通过设置每一段末端的随机高度,生成两侧对称的粗糙裂隙面。基于格子Boltzmann方法,采用不可压缩流体的D2G9模型,验证了经典的Poiseuille流,计算了不同相对粗糙度岩体裂隙的渗流特性,讨论了裂隙面粗糙度对渗流流态的影响。研究结果表明:裂隙结构壁面对流体的阻碍作用,使得流体在壁面附近的流动产生急剧调整,同时随着裂隙相对粗糙度的增加,在裂隙隙宽急剧变化的部位,局部伴随着旋涡的形成,导致流体内部摩擦阻力作用增大。在单位时间截面渗流流量及每一段平均隙宽相等的条件下,将本数值解与多平行板理论解进行了对比,对于相对粗糙度δ=0.01674的裂隙方案,由于多平行板理论解忽略了粗糙裂隙隙宽变化而引起的局部压降,其裂隙中线处压降产生的最大误差达到15.2%。当相对粗糙度较小时,裂隙中线处的压力与光滑平板流相类似,近似呈线性变化。随着裂隙相对粗糙度增大,压力变化偏离直线方向,且在断面由窄突然变宽的部位,压力变化偏离线性尤为显著。
[Abstract]:In order to study the relationship between the roughness of rock fracture surface and the seepage mechanism, the fracture is evenly divided into several segments along the length direction. By setting the random height at the end of each segment, the symmetrical rough fracture surface on both sides is generated. Based on the lattice Boltzmann method and the D2G9 model of incompressible fluid, the classical Poiseuille flow is verified. The seepage characteristics of cracks with different relative roughness are calculated, and the influence of roughness of fracture surface on seepage flow is discussed. The results show that the fluid flow near the wall is adjusted rapidly due to the obstruction of the fissure wall, and at the same time, with the increase of the relative roughness of the fissure, the width of the fissure changes dramatically. Local vortex formation leads to the increase of friction resistance in the fluid. Under the condition that the seepage flow rate per unit time section and the average gap width of each section are equal, the present numerical solution is compared with the theoretical solution of multiple parallel plates. For the fracture scheme with relative roughness 未 = 0.01674, The local pressure drop caused by the variation of the gap width of the rough fracture is neglected in the multi-parallel plate theory, and the maximum error of the pressure drop at the center of the crack is 15.2. When the relative roughness is small, the pressure at the center of the fracture is similar to that of the smooth plate flow, and it is approximately linearly changed. With the increase of the relative roughness of the fracture, the pressure variation deviates from the straight line direction, and the pressure variation deviates linearly especially in the position where the section is suddenly widened from narrow to narrow.
【作者单位】：昆明理工大学建筑工程学院;中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室;
【基金】：国家自然科学基金项目(51408284,51508253,U1502232) 昆明理工大学人才培养基金项目(KKSY201306023)
【分类号】：TU45

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