Quantitative visualization methods for continuous evolution of three-dimensional discontinuous structures and stress field in subsurface rock mass induced by excavation and construction - An overview

Discontinuous structures such as pores, fractures, joints, and faults govern the physical and mechanical behavior of subsurface rock masses in underground engineering applications. The excavation of subsurface energy resources and construction activities extensively change the discontinuous structures and stress distribution in the surrounding rock masses. These hidden and dynamic changes are extremely difficult to detect and characterize using conventional methods and techniques, and this has greatly impeded the study of the intrinsic mechanisms governing the deformation and failure of rock masses. In the past few years, discontinuous rock structure imaging methods and three-dimensional printing (3DP) technology have been successfully applied to replicate rock mass samples for geological and geophysical research purposes. The combination of these methods has led to innovative ways to investigate the behavior of complex rock and guide underground engineering applications. This review focuses on the characterization and visualization of (1) the interior discontinuities of rock masses, and (2) the stress distribution and its continuous evolution in the discontinuous rock masses. Recent progress in experimental and computational methods in identifying and characterizing the discontinuous structures are presented. In particular, we discuss the development and process of integrating computed tomography (CT), 3DP technology, transparent rock models, and optical mechanics methods to quantitatively and visually present the interior structures and stress evolution inside rock masses. •Recent progress in visualizing the hidden structure and stress of rock is reviewed.•Methods to characterize the interior discontinuities of rock are addressed.•Experimental visualization of the stress evolution in rock models is highlighted.•Integration of computed tomography, 3D printing and optical methods is introduced.•The limitation of current methods and future research directions are discussed.