Surrounding rock deformation refers to the time-dependent change in shape and position of the rock mass immediately adjacent to an underground excavation — such as a tunnel, roadway, cavern, or borehole — caused by the redistribution of in-situ stress after excavation [1]. Before excavation, the rock is in equilibrium under the virgin stress field; removal of material at the opening boundary causes stress concentration around the opening and induces displacements — radial convergence, wall displacement, roof sag, and floor heave — that may be elastic, elastoplastic, or viscoelastic depending on rock-mass quality, depth, and groundwater conditions [2]. The deformation field is governed by the stiffness, strength, and discontinuity geometry of the rock mass and is commonly analyzed using the convergence–confinement method, in which a ground-reaction curve relates radial displacement at the wall to the support pressure provided by linings, rock bolts, or shotcrete [3]. The term is distinguished from intact-rock deformation measured on laboratory specimens and from surface subsidence by its scale and by its location within the rock mass around the opening.
Rock Mechanics and Modeling • Mechanics of Materials • Engineering • Physical Sciences