荷载和水压力作用下岩石裂纹贯通过程的数值模拟研究

STUDY ON CRACK COALESCENCE PROCESS UNDER LOADING AND HYDRAULIC PRESSURES

应用自主开发的数值模拟系统F-RFPA^2D，研究荷载和水压力作用下岩石裂纹和内部缺陷结构相互作用下的贯通过程，内容包括岩石应力应变过程中，不同裂纹扩展阶段的渗透率演化规律，水压力对裂纹扩展模式和峰值强度的影响，岩石内部缺陷结构对裂纹贯通模式的影响等。结果表明，水压力和缺陷结构分布的非均匀性对岩石的应力峰值强度、峰值前后渗透性演化规律及裂纹贯通机制影响十分明显。

The coupling action of seepage and fracture on crack coalescence process under loading and hydraulic pressures are investigated. Numerical results demonstrate that the trend and magnitude of the permeability variations are controlled by the stress and the damage evolution developed in rocks. This includes the induced stress evolution of flow properties, and the regions of both diminished and enhanced flow depending on which the rock is in the linear-elastic, nonlinear, or post-failure portions of the stress-strain curves are presented. In elastic deformation region, rock permeability reduces when the rock compacts, and the decrease rate of the permeability starts to slow down or gradually to increase again when micro fractures begin to nucleate. Dramatic permeability increase occurs as soon as the macro-fracture forms in the rock.