基于岩石变形破坏过程的岩柱稳定性分析

地下采矿过程中岩柱承载能力与变形破坏是一个重要的工程问题。文章根据岩柱失稳破坏与岩石压缩破坏过程的相似性与砂岩试验单轴破坏过程中声发射特点,将岩柱破坏前分为压密、弹性阶段、稳定破裂和非稳定破裂四个个阶段,并分析了岩柱破坏过程中不同阶段特征。试验揭示岩石破坏过程中在屈服点附近伴随着岩石内部微破裂快速萌生和生长,声发射事件数会出现大幅度增加。根据岩石破坏形态多呈现为沿着一个或多个凹凸不平的破裂面,在声发射-应变曲线上存在声发射突增点,声发射峰值点近似在应力强度峰后拐点处。同时,指出在岩柱失稳破裂的发射突增现象可作为岩柱承载力变化特征点,并可为岩柱承载力分析提供依据。

The Stability of Mine Pillar Based on Whole Stress-Strain Process

The research of pillar stability and bearing capacity is a hot topic and key point in underground mining. Comparing the similarity of mine pillar failure with rock compression process, and combining the AE (acoustic emission) character of rock uni-axial compression test results, it is shown that the instability process of mine pillar has different stages. Analyzing the relationship of AE and rock compression process under loading, the failure process of mine pillar is classified into four stages according to the different deformation before its damage, which are the compaction stage, the elastic stage, stable cracking stage and unsteady crack growth stage. From the test, it is revealed that the number of acoustic emission events has a rapid increase in the process of rock damage near the yield point with the fast initiation and growth of micro fracture. The rock failure pattern appeared as along one or more uneven fracture surfaces, there was a peak jumping point of AE in AE-strain curve. The AE peak point is near the inflection point on stress-strain curve. The characteristics of increasing of AE in unsteady crack growth stage can be used to provide geological and scientific foundation for analysis on pillar stability and bearing capacity.