基于数字图像处理的含不同开度裂隙组合花岗岩破裂规律研究

Study on fracture law of granite with different aperture based on digital image processing

为了研究不同开度裂隙组合花岗岩破裂规律,通过RFPA 2D-DIP数值模拟软件中的数字图像处理功能,建立含不同开度裂隙组合的花岗岩细观结构模型,进行单轴压缩数值试验,分析了模型的应力-应变曲线特征、峰值强度特征、裂纹扩展规律和声发射特征。结果表明:数字图像处理技术能够很好地表征花岗岩细观组分的非均匀性,所建立的模型更加真实可靠;不同开度裂隙组合模型的力学响应特征和破裂规律存在差异,随着开度增加,应力-应变曲线上升与跌落次数增加,峰值强度和声发射总次数降低,且由拉伸破坏向拉剪混合破坏转变;裂隙扩展存在开度阈值,当开度大于等于2 mm时,裂隙起裂并以翼型裂纹进行扩展;开度较大的裂隙扩展优先于开度较小裂隙,是决定破裂形态的主控裂隙。岩体工程失稳破坏是其中大小不一的裂隙起裂、扩展及贯通的结果,研究结果对探究岩石破裂规律具有一定的指导意义。

In order to study the fracture law of granite assemblage with different aperture,the real microstructure of granite with different aperture is established by the digital image processing function of RFPA2D-DIP numerical simulation software.And the uniaxial compression numerical test is carried out.Based on the test results,the variation characteristics of stress-strain curve,peak strength characteristics,fracture propagation law at different stages of the model and acoustic emission characteristics in the process of model fracture are analyzed.The results show that the digital image processing technology can well characterize the heterogeneity of granite mesoscopic components,and the established model is more realistic and more reliable.The mechanical response characteristics and fracture law of models with different aperture are different.As the aperture degree increases,the stress-strain curve rises and the number of drops increases,the total number of peak strength and sound emission decreases,and the failure changes from tensile failure to tensile shear mixed failure.There is an aperture threshold for fracture propagation.When the aperture is more than 2 mm,the fracture starts to crack and expands as airfoil fracture.The fracture with larger aperture is the main control fracture which determines the fracture morphology.Rock mass engineering instability failure is the result of fracture initiation,expansion and transference of fractures with different aperture.The research results have certain guiding significance for exploring the law of rock fracture.