Effects of natural fractures on pressure drawdown and damage evolution around excavation in fractured rocks

Abstract

The paper presents a hydro-mechanical model for simulating excavation-induced EdZ/EDZ formation and groundwater depressurisation in fractured rock masses. Damage of intact rocks is simulated by an elasto-brittle damage model, while the deformation of natural fractures is modelled by an elasto-perfectly plastic constitutive law. The fluid flow in the fractured porous rock obeys Darcy's Law. A case study based on the site characterization data of a crystalline rock at Sellafield is presented, where significant hydro-mechanical responses induced by excavation and drainage are observed, including stress redistribution, damage evolution, fracture deformation, and pressure drawdown. The research findings of this paper have important implications for many geoengineering applications such as tunnel excavation, wellbore exploitation and waste deposition.