Artículo
A criterion for the extent of damage around excavated brittle hard rock masses in terms of its convergence over time
Fecha
2020Registro en:
conference
9780367422844
Autor
Universidad San Sebastián
Universidad San Sebastián
Universidad San Sebastián
Universidad San Sebastián
Cabezas, R. E.
Vallejos, J. A.
da Fontoura, Sergio A.B.
Rocca, Ricardo José
Mendoza, José Félix Pavón
Institución
Resumen
When stress redistribution around deep excavations surpasses rock mass strength, several mechanical instabilities may appear, inducing damage in the surrounding rock mass, which can be observed as a convergence of the walls over time. The damage extension affects the volume where ground support is installed, and convergence may provide valuable information for tunnel stability. This study analyzes several cases for recorded convergence and calibrates that data with estimations of damage using numerical models and measurements inside the rock mass. Hence, a new criterion is proposed for relating observed in-situ deformations to the decay within the rock mass and the extension of damage. An estimated damage curve may be induced as a function of the total strain at surface for compressive stress and buckling in tensile failure. The formulation is consistent with other studies regarding critical plastic strain (CPS), dilatancy and microseismicity. Further extension to full 3D capabilities is addressed and proposed for further investigation. When stress redistribution around deep excavations surpasses rock mass strength, several mechanical instabilities may appear, inducing damage in the surrounding rock mass, which can be observed as a convergence of the walls over time. The damage extension affects the volume where ground support is installed, and convergence may provide valuable information for tunnel stability. This study analyzes several cases for recorded convergence and calibrates that data with estimations of damage using numerical models and measurements inside the rock mass. Hence, a new criterion is proposed for relating observed in-situ deformations to the decay within the rock mass and the extension of damage. An estimated damage curve may be induced as a function of the total strain at surface for compressive stress and buckling in tensile failure. The formulation is consistent with other studies regarding critical plastic strain (CPS), dilatancy and microseismicity. Further extension to full 3D capabilities is addressed and proposed for further investigation