3D-DIC系统在岩石力学试验中的应用

介绍了全场3D-DIC系统，在试样周围均匀布置三组3D采集元，利用散斑图像的采集，尽可能在较大范围内捕捉试样表面的变形并进行分析。为了验证3D-DIC系统测量结果的可靠性，以江持安山岩为试验材料，进行了单轴压缩条件下的恒定应变速率和交替应变速率试验。通过3D-DIC系统的测量结果与应变片测量结果的对比发现，两者吻合度较好，表明3D-DIC系统能够满足岩石力学试验非接触式、可视化变形测量的需求。另外以田下凝灰岩为试验材料，通过图像分析得到了加载过程中岩石表面的全场变形信息，发现岩石变形的不均匀性和应变局部化现象，表明利用3D-DIC系统对岩石破裂过程变形测量比传统变形测量方法更具有优越性，为岩石力学试验研究提供了一种新的、便捷的测试方法。

Application of 3D-DIC system in rock mechanic test

The full field three-dimensional digital image correlation (3D-DIC) system is introduced, the system comprises three groups of the 3D acquisition units setting around the cylindrical specimen to cover the maximum surface area as much as possible. The speckle images are collected during test and used to analyze the deformation of the specimen. For verifying the reliability of measured results of the 3D-DIC system, the constant strain rate and alternative strain rate tests are conducted with Emochi andesite in uniaxial compression, the results are coincident with each other by comparing the measured results of 3D-DIC and strain gage, which indicates that the 3D-DIC system can meet the requirements of non-contact and visual deformation measurement of rock mechanics test. Moreover, taking Tage tuff as object, the evolutions of displacements and strain fields are obtained by images analysis, the non-linear and localized deformation of specimen are observed at the same time. The results indicate that it is more effective to study the rock deformation by using 3D-DIC method than that by using conventional methods. The 3D-DIC system provides a new and advanced test method for investigation of rock mechanics.