节理岩体损伤破裂中的渗透性演化与能量耗散

根据损伤力学和统计强度理论,在真实破坏分析方法(RFPA)的基础上建立了损伤过程渗透模型,基于离散裂隙网络(DFN)模型生成随机正交节理岩体数值试样,对岩体损伤-渗流-能量耗散的完整过程以及渗流通道的形成变化进行了精细模拟。数值试验表明,节理岩体在峰后软化和残余变形阶段依然存在大量的新生裂隙持续发育,同时也伴随能量的不断耗散。渗透性的激增显著滞后于峰值荷载,往往在峰后数倍峰值应变处才形成贯穿岩体的完整渗流通道,渗透性瞬间阶跃到极大值。利用渗流的滞后性,可以通过微震监测手段对矿山突水灾害进行有效的监控预警,在张马屯铁矿地下防水帷幕突水预警的工程实践中取得了良好效果。

Research on Permeability Evolution and Energy Dissipation Law During Damage and Fracturing of Jointed Rock Masses

According to the damage mechanics and statistical strength theories, a seepage model for the damage process was established by using the Real Failure Process Analysis (RFPA) program. A numerical rock core with random orthogonal joints was generated based on the Discrete Fracture Network (DFN) model, and the full damage-seepage-energy dissipation process and the formation of seepage channels were described elaborately. The simulation results indicate that a great amount of new fractures are continuously developed in the jointed rock mass during the post-peak softening and residual deformation stages, accompanied by continuous energy dissipation. The rapid increase of seepage obviously lags behind the peak loading. Complete seepage channels cross the rock mass are usually formed when the strain is a few times of the peak strain. Correspondingly, the seepage coefficient jumps to a very large value instantaneously. By utilizing the seepage lagging effect, the microseismic monitoring technique can be applied for monitoring and early-warning of geological hazards in ore mines. This method has been successfully applied in early-warning of water inrush hazards in Zhangmatun Iron Ore.