考虑三维形貌特征粗糙裂隙加卸载渗流规律研究

Seepage law of rough fracture during loading-unloading process considering 3D topography characteristics

裂隙岩体在天然地质因素和人工扰动作用下处于加卸载环境是普遍存在的,裂隙面的几何特征和加卸载环境对裂隙渗流特性的影响在实际工程中不可忽视。采用试验和数值模拟相结合的方法,利用热-流-固三场耦合渗流试验系统,开展了应力加卸载作用下不同粗糙度裂隙岩芯试件的渗透试验,自主开发程序将激光扫描裂隙面的三维形貌信息导入到ABAQUS软件,模拟应力作用下的粗糙裂隙渗流。试验和数值模拟一致表明,粗糙裂隙的宽度和渗透率都随载荷的增加而减小,随着载荷的增加,裂隙接触刚度增大,裂隙的宽度和渗透率对载荷变化的敏感性降低;由于点接触产生的塑性变形不可恢复,卸载阶段的裂隙宽度和渗透率增加幅度减小,且小于加载阶段同载荷条件下的宽度和渗透率;裂隙渗透率、宽度与粗糙度呈正相关关系,且粗糙度越大,接触应力分布越不均匀;裂隙内流场符合群岛流,粗糙度越大群岛流现象越明显。

Fractured rock mass under loading and unloading environment is ubiquitous with the influence of natural geological and artificial disturbance; the fracture surface geometry and the influence of unloading environment on fracture seepage characteristics can not be ignored in actual engineering. Using the methods of combining experimental and numerical simulation, to do the seepage flow experimental of fractured core with different roughnesses under loading and unloading, the thermo-hydro-mechanic coupling seepage flow system are used, to import the three dimensional morphology of fracture surface obtained by laser scanning into ABAQUS, the self-developed program is introduced. Both experimental and numerical simulations show that: The width and permeability of rough fracture decreases with the increase of load. With the increasing of load, the contact stiffness of fracture increases and the sensitivity of width and permeability decrease. The plastic deformation caused by points contact can not be recovered, The increasing amplitude of width and permeability of fracture decrease in stage of unloading, and less than that in loading stage under same conditions. Permeability, width and roughness of fracture were positively correlated. The greater the contact stress distribution is, the greater the roughness is. The field of flow in the crack is flow around islands, the greater the roughness, the phenomenon of flow around islands more obvious. © 2016, Science Press. All right reserved.