基于三维重构的数字岩心应力加载实验研究

Experimental study of digital core stress loading based on 3D reconstruction

传统数字岩心技术在建立三维模型的过程中存在局限性,导致数值模拟的试验分析精度较差。为优化建模技术,采用CT扫描+MATLAB图像处理+AVIZO三维重构方法改善传统建模方式,依托ABAQUS数值模拟软件建立三维数字岩心模型。通过与室内试验进行对比,标定数字岩心的物理力学参数,并构建微单元数字岩心模型探究单轴应力加载过程中的损伤演化规律。结果表明:建立的三维数字岩心模型可以很好的捕捉室内试验测试的应力—应变曲线特征,并且具有相同的裂纹扩展方式。微单元数字岩心模型内部多种介质的分布状态极大影响了岩心的应力与损伤演化过程。其中,拉伸损伤明显滞后于压缩损伤的发展,同时拉伸损伤区域也明显较低,在峰后区域两者相差约74倍。

The traditional digital core technology has some limitations in the process of establishing three-dimensional model,which leads to the poor accuracy of numerical simulation test analysis.In order to optimize the modeling technology,CT scanning+MATLAB image processing+AVIZO 3D reconstruction method improves the traditional modeling method,and relies on ABAQUS numerical simulation software to establish a 3D digital core model.The physical and mechanical parameters of digital core were compared with those of laboratory tests,and a microunit digital core model was constructed to explore the damage evolution law during uniaxial stress loading.The results show that the established 3D digital core model can capture the stress-strain curve characteristics of laboratory test well,and has the same crack propagation mode.The distribution of multiple media in the microcell digital core model greatly affects the evolution of stress and damage in the core.Among them,the development of tensile damage lags behind that of compression damage,and the tensile damage region is also significantly lower,with a difference of about 74 times in the postpeak region.