工程深部开采活动中,岩石周围应力环境较为复杂,且对扰动作用极为敏感。在已经提出的岩石“蠕变扰动效应”以及“强度极限邻域”概念的前提下,利用CT技术手段对岩石“强度极限邻域”内、外进行微观扫描探测,观察岩石内部损伤变化过程,同时运用单位像素坐标点建立孔隙之间距离,并结合工程实例得出以下结论:①分析横、纵应力-应变曲线可知,岩石在纵向与横向同时存在一个长期强度,且岩石进入横向长期强度优先纵向,但是通过CT扫描岩石内部孔隙结构变化可知,岩石纵向长期强度阈值相比横向更准确;②通过分析岩石轴向CT扫描图,在轴压45MPa时,岩石内部只出现新的较少孔隙结构,且内部孔隙并未出现相连贯通现象;而在轴压50MPa时,未扰动时就可清楚看出岩石内部新的孔隙结构出现贯通现象,随着扰动的施加,岩石内部出现明显的裂痕条纹,说明岩石“强度极限邻域”为45~50MPa,可知以纵向长期强度判断“强度极限邻域”更具有说服力;③对CT扫描后的岩石试件进行伪彩色处理,利用岩石像素特征点之间的距离建立孔隙之间的距离,通过分析轴压40MPa与45MPa下岩石扰动前后的像素特征点之间距离可知,其只是略微的增加或减少;而在轴压50MPa下,岩石扰动前后像素特征点坐标值出现突增,像素特征点间的距离增加了214.27,说明岩石“强度极限邻域”为45~50MPa,且岩石在此轴压时对扰动极为敏感;④结合工程实例分析,判断其岩石“强度极限邻域”,通过应变曲线变化范围为工程实例及时提供有效预警,同时也为地下工程的岩石扰动提供理论依据。

During engineering deep mining activities,the stress environment surrounding the rocks is highly complicated and particularly susceptible to the impacts of disruption. The concept of "creep perturbation effect"  and "strength limit neighborhood" of rocks is used to investigate the damage process inside and outside the "strength limit neighborhood" of rocks using CT technology for the first time. This investigation is based on the concept of "creep perturbation effect". Using the microscopic sweeping probe,one can witness the process of the rock     being damaged from the inside. At the same time,the distance between pores is calculated by making use of the coordinates of unit pixels,and the subsequent conclusions are arrived at by integrating this information with engineering examples. ① Analysis of stress-strain curves reveals that the rock exhibits long-term strength in both  the longitudinal and transverse directions,with the longitudinal direction demonstrating a higher preference      for entering the transverse long-term strength. The study of pore structure changes through CT scans suggests that  the longitudinal long-term strength threshold of the rock is more accurate than the transverse threshold. ② Under  an axial pressure of 45 MPa,the rock's CT scan reveals a new pore structure with fewer pores inside the rock,which appears unconnected or punctured. Even under an axial pressure of 50 MPa,the penetration of new pore structures into the rock remains unaffected. Distinct fracture tracks are visible,indicating the presence of a "strength      limit neighborhood" between 45 MPa and 50 MPa. The rock exhibits considerable strength,particularly when     the "strength limit neighborhood" is defined longitudinally. ③ Pseudocoloration techniques were used to calculate the distance between pores based on the pixel separation. A comparison and analysis of axial pressures at 40 MPa and 45 MPa showed a reduction in pixel distance,while at 50 MPa,there was a sudden increase of 214.27     pixels before and after disturbance. This indicates the existence of a "strength limit neighborhood" between   45 MPa and 50 MPa,where the rock is highly sensitive to disturbance. ④ By combining analysis with actual engineering examples,the determination of the rock's "strength limit neighborhood" allows for effective early  warning based on changes in strain curves. This approach provides a theoretical foundation for underground engineering.