Using Image analysis method to determine the degree of saturation of unsaturated sand

Abstract

The hydraulic properties of unsaturated soil provide important information on fluid movement in geological systems. The degree of saturation of unsaturated soil, recognized as one of the most critical hydraulic properties, is crucial for geotechnical problems such as slope stability, bearing capacity, and seepage. Computer vision for digital image processing approaches has been widely used recently, with applications in many aspects of construction and geotechnical engineering. The objective of this research is to use the digital image processing (DIP) method to determine the degree of saturation of unsaturated sand. The RGB image of the soil column is processed into a grayscale channel and becomes a matrix for processing calculation. The fluctuation of pixel values extracted from computer vision is correlated with the change in the degree of saturation of the sand. Hence, DIP techniques can be considered as an effective tool to establish the soil - water characteristic curve (SWCC) of unsaturated soil. Furthermore, employing matrix processing techniques can help improve the reliability of the SWCC derived from the correlation between image pixel values and the degree of saturation of unsaturated soil by identifying and mitigating the influence of outliers. The results demonstrate a strong correlation between the degree of saturation obtained through digital image processing techniques and the measured values from resistivity probe techniques.