2019 年 7 巻 2 号 p. 31-37
Triaxial tests have been extensively used to characterize soil behavior. During triaxial testing, the soil deformation needs to be measured. However, measurement of deformation in unsaturated soils is considered a great challenge for researchers due to the existence of air phase. Over the years, a great deal of research effort has been dedicated to developing methods to measure soil deformation during triaxial testing. Among these methods, image-based methods receive increasing attention. This state-of-the-art report presented herein aims at documenting advancement in the image-based methods for unsaturated soil deformation measurement. The documentation presented this study includes the image analysis, X-ray CT, image correlation, multi-camera photogrammetry, and the photogrammetry-based methods. The pros and cons of each method are discussed and a comprehensive comparison between these methods is provided. Concluding remarks are included in the last section of the report.