基于数字图像处理的含缺陷花岗岩破裂力学分析1）

摘要

在细观尺度上，采用数字图像处理技术研究花岗岩中由石英、长石和云母等材料的形状、大小及分布对花岗岩材料造成的非均匀性，结合RFPA-DIP程序建立了能准确反映材料真实细观结构的含缺陷花岗岩数值模型，并进行了常规单轴压缩模拟试验，研究不同矿物颗粒结构与缺陷对其细观破裂力学行为的影响，再现了外载荷作用下不同数值模型的真实破裂过程与最终破坏模式。试验结果表明：缺陷对试样强度的影响比改变矿物颗粒的形态构造对其强度的影响更加显著，缺陷的存在削弱了颗粒形态对花岗岩强度影响的能力；缺陷及矿物颗粒的形态构造对试样裂纹的萌生、扩展以及最终破坏模式有直接影响，缺陷与矿物颗粒的空间结构关系是导致岩石形成各种复杂破坏模式的主要因素。起裂应力水平受试样内部细观介质构造和缺陷的影响，而缺陷的存在对起裂应力的影响更加显著。%At the meso-scale, the digital image processing technology is adopted to characterize the heterogene-ity of granite caused by different distributions, sizes and shapes of quartz, feldspar, mica, etc., combining with RFPA-DIP to establish a numerical model of flawed granite. The model can reflect the real meso-scale behaviors of material accurately. The simulation tests of conventional uniaxial compression are carried out, the influences of diverse mineral particle structures and flaws on the meso-fracture behaviors are studied, to reveal the realistic failure process and final failure mode based on different numerical models under the external load. It is shown that the influence of the flaws on the strength of the sample is more significant than that of the transformation of the mineral particle structure. The existence of flaws weakens the influence of the particle morphology on the strength of granite;the flaws and the structures of mineral particles have a direct influence on the initiation and the propagation of crack and the final failure mode of samples, the spatial structure of mineral particles and flaws is the main factor for the complex failure modes of the rock. The inner-microstructure and the flaws of samples influence the crack initiation stress level, and the existence of flaws has a more significant effect on the crack initiation stress.