开挖扰动下矿柱损伤破裂失稳细观机制研究

为揭示开挖扰动下矿柱损伤破裂失稳的细观机制, 以盘龙铅锌矿采场间柱破裂为原型, 运用PFC^2D对其破坏机理进行反演分析, 建立基于声发射累计数的尖点突变失稳判别模型。研究结果表明:采空区上方形成压力拱, 拱内岩体自重转移到附近围岩和矿柱, 产生应力集中; 矿柱受压逐渐产生损伤, 其损伤破裂失稳演化过程分为3个阶段:弹性阶段、屈服阶段、失效阶段; 矿柱内部以拉裂纹为主, 细观破坏形式主要为拉伸破坏, 宏观表现为剪切滑移破坏。经验证, 基于声发射累计数的尖点突变模型能够有效判别矿柱失稳状态。

Meso-mechanism of Damage and Failure of Pillars by Excavation Disturbance

In order to reveal the meso-mechanism of the pillar damage and failure caused by excavation disturbance, PFC^2D was adopted for the inverse analysis of the failure mechanism for Panlong Lead-Zinc Mine with the interval pillars in the stope mining. And a cusp catastrophic model for instability detection was established based on the cumulative number of acoustic emissions. The results showed that the pressure arch was formed above the goaf, and the weight of rock mass in the arch was transferred to the surrounding rock and pillar, resulting in the concentrated stress. The pillar was gradually damaged under pressure, with the damage and fracture evolution process divided into three phases: elastic phase, yielding phase and failure phase. The tensile crack was the predominant failure in the pillar, with tensile failure as the predominant mesoscopic failure mode and the shear slip failure as the macroscopic performance. It was verified that the cusp catastrophe model based on the cumulative number of acoustic emission could effectively determine the instability of the pillar.