裂隙岩石细观-宏观损伤演化机制及渐进破坏失稳机理

Rock mass damage caused by instability is one of the major disasters in mining rock engineering, it has important meanings in theory and practice to deeply research the disaster induced mechanism, especially the micro to macro damage evolution and instability mechanism. By the means of theoretical analysis, laboratory test and numerical simulation, the instability disaster mechanism of fracture rock is studied from the meso-scale. Firstly, the physical characteristics of fractured rock were obtained through the SEM and other meso-scale tests, a method combining digital speckle measurement and slow loading test synchronous is carried out to the prefabricated cracked rock, and also based on the energy poly release principle of acoustic emission test, the mechanical mechanism and evolution characteristics of micro crack propagation to macroscopic crack is obtained, and the constitutive relation of meso damage for fractured rock is established. Secondly, based on the fractal feature of crack growth microstructure, fractal dimension is used as the equivalent parameters of the micro strength weakening index corresponding to the macroscopic damage of rock, then the F-BPM model based on fractal dimension is constructed and verified. Finally, the constitutive relation is embedded in PFC program by Fish language, and combined with the model of F-BPM, the numerical expansion research is carried out, the induced mechanism of the fractured rock progressive failure that influenced by meso structure is revealed, which provide theory basis for instability disaster accident prevention and control for surrounding rock.

岩体失稳致灾是矿山岩石工程中的重大灾害之一，深入研究其灾变诱发机制，特别是其细-宏观损伤演化及失稳机理具有重要的理论与现实意义。本课题采用理论分析、室内试验与数值模拟相结合的手段，从细观尺度深入研究裂隙岩石损伤演化机制及渐进破坏失稳机理。首先，通过SEM等细观试验获取裂隙岩石细观物性特征，通过对预制裂隙岩石进行低速率单轴加载、数字散斑测试同步试验相结合的方法，结合声发射试验的能量聚释变化，获取微裂隙扩展到宏观裂纹的力学机制和演化特征，建立裂隙岩石细观损伤本构关系；其次，基于裂纹扩展细观结构分形特征，将其作为岩石宏观损伤对应的细观强度弱化指标的等价参量，构建基于分维表征的F-BPM模型并验证优化；最后，采用FISH语言编程将获取的本构关系嵌入PFC程序中，结合F-BPM模型开展数值扩展研究，深入揭示细观结构物性对含裂隙岩石渐进破坏失稳灾变的诱发机制，为巷道围岩失稳灾害事故防控提供理论依据。

岩体失稳致灾是矿山岩石工程中的重大灾害之一，深入研究其灾变诱发机制，特别是其细-宏观损伤演化及失稳机理具有重要的理论与现实意义。针对矿山岩体失稳灾变问题，本课题根据计划任务书要求，采用理论研究、实验室试验、数值模拟与现场探测相结合的手段，对岩石细观-宏观损伤演化机制及渐进破坏失稳机理开展了研究。首先，通过SEM等细观试验获取岩石裂隙等细观结构及物性特征，通过对岩石试件进行低速率单轴加载，基于试验岩石细观结构物性进行分形特征分析，分析其与强度、均质度系数等岩石宏观损伤参数的相关性；其次，通过单轴压缩及数值模拟等方法结合声发射特征得到裂隙损伤演化的能量聚释变化，并获得了微裂隙扩展到宏观裂纹的力学机制和演化特征，建立了典型岩石损伤本构模型；最后，基于裂纹扩展细观结构分形特征，结合BPM模型进行数值模拟分析并进一步优化，开展数值扩展研究，深入揭示了细观结构物性对岩石渐进破坏失稳灾变的诱发机制，辨识岩体失稳主控因素并进行了安全性评价，给出了评价指标和评价模型，为岩石失稳灾害防治提供了理论依据。