Digital Volume Correlation (DVC) is widely used for the analysis of three-dimensional displacement and strain fields based on CT scans. However, the applicability of DVC methods is limited when it comes to geomaterials: CT speckles are directly correlated with the material's microstructure, and the speckle structure cannot be artificially altered, with generally poor speckle quality. Additionally, most geomaterials exhibit elastoplastic properties and will undergo complex-large deformations under external loading, sometimes leading to strain localization phenomena. These factors contribute to inaccuracies in the displacement field obtained through DVC, and at present, there is a shortage of correction methods and accuracy assessment techniques for the displacement field. If the accuracy of the DVC displacement field is sufficiently high, the gray residue of the two volume images before and after deformation should be minimal, utilizing this characteristic to develop a correction method for the displacement field is feasible. The proposed self-correcting strategy of the DVC displacement field based on image matching, which from the experimental measurement error. We demonstrated the effectiveness of the proposed method by CT triaxial tests of granite residual soil. Without adding other parameters or adjusting the original parameters of DVC, the gray residue showed that the proposed method can effectively improve the accuracy of the displacement field. Additionally, the accuracy evaluation method can reasonably estimate the accuracy of the displacement field. The proposed method can effectively improve the accuracy of DVC three-dimensional displacement field for the state of speckles with poor quality and complex-large deformation.

翻译：数字体积相关（DVC）技术广泛应用于基于CT扫描的三维位移与应变场分析。然而，DVC方法在岩土材料中的应用存在局限：CT散斑直接关联于材料的微观结构，且散斑结构无法人为改变，通常散斑质量较差。此外，大多数岩土材料表现出弹塑性特性，在外部荷载作用下会发生复杂大变形，有时还会出现应变局部化现象。这些因素导致通过DVC获得的位移场存在误差，而目前针对位移场的校正方法与精度评估技术较为缺乏。若DVC位移场精度足够高，则变形前后两幅体图像之间的灰度残差应极小，利用这一特性开发位移场校正方法是可行的。本文提出一种基于图像匹配的DVC位移场自校正策略，该方法源于实验测量误差。通过开展花岗岩残积土的CT三轴试验，验证了所提方法的有效性。在不增加其他参数或调整DVC原始参数的情况下，灰度残差结果表明该方法能有效提升位移场精度。此外，所提精度评估方法能合理估计位移场的准确性。该方法可显著改善DVC在散斑质量差与复杂大变形状态下三维位移场的计算精度。