Numerical simulation of thermal-mechanical processes observed at the Drift-Scale Heater Test at Yucca Mountain, Nevada, USA

Results from the 4-year-long heating phase of the Drift-Scale Heater Test at the Exploratory Studies Facility at Yucca Mountain, Nevada, USA, provide a basis to evaluate conceptual and numerical models used to simulate thermal-mechanical coupled processes expected to occur at the potential geologic repository at Yucca Mountain. The objectives of the evaluation were to investigate coupled processes associated with (i) temperature effects on mechanical deformation and (ii) effect of thermal-mechanical processes on rock-mass permeability. Two-dimensional numerical models were built to perform the thermal-mechanical analyses. Thermal-mechanical simulations were predicated on a continuum representation of a deformation-permeability relationship based on fracture normal stress. The estimated trend of permeability responses using a normal stress-based deformation-permeability relationship compared reasonably to that measured in the coupled thermal-mechanical analyses.