Quantification of the stress field in extremely complex pores by digital photoelasticity

Quantification of stress fields in complex pores is essential for understanding the failure mechanisms of engineering geomaterials. Photoelasticity has been widely used to analyze stress fields in engineering. However, difficulties in model fabrication and stress field extraction limit its application for models with extremely complex structures, such as pores and fractures in rocks. In this study, the regional phase unwrapping algorithm was improved to efficiently determine the isoclinics by dividing the regions of the isoclinics in the interval (0, π/2). Furthermore, a photoelastic model with extremely complex pore structures in conformity with natural rocks was fabricated using a 3D printing technique. The isoclinics and isochromatics were calculated using the improved method. The good accuracy was verified by comparing the photoelastic fringe orders with the darkest and brightest fringes. The fabrication of complex photoelastic models and the efficient extraction of full-field stress will expand the application of photoelasticity in broader fields.