Review on image-based non-destructive observation methods for soil meso-liquefaction process.

Investigation of the mechanisms of soil liquefaction using imaging techniques from a mesoscopic perspective is essential for thorough characterization and quantification. However, the scope of this research has been limited by the growing knowledge of the mechanisms behind soil meso-liquefaction. Several approaches to soil meso-observation are currently available, but important issues such as the creation of an appropriate scheme, the determination of key meso-parameters, and the completion of quantitative studies remain unresolved. This article reviews the main roles and applications of meso-observation techniques, including meso-imaging systems, scanning electron microscope (SEM) and X-ray computed tomography (CT), in soil investigations. The evolution of soil particle meso-contact, changes in pore size and classification, long axis particle orientation and the influence of meso-parameters such as mean fractal dimension and directional probability entropy are highlighted. Finally, the paper analyses the challenges and development directions of soil meso-liquefaction observation methods and soil meso-liquefaction mechanism research. Soil meso-liquefaction mechanisms can be studied better with the help of a summary of the meso-observation techniques used in most liquefaction experiments. In order to acquire the necessary study parameters for the obtained image, the corresponding image processing methodologies were summarized. The current state of the study of the meso-liquifaction mechanism, used structural meso-parameters of the soil, provides a basis for choosing future research and a useful idea for further study of the meso-liquifaction mechanism of soil in order to better understand and control liquidation. [ABSTRACT FROM AUTHOR]