Permeability Drift Scale Test

Rutqvist, J., C.-F.Tsang, and Y.Tsang, 2003. Analysis of Stress and Moisture-Induced Changes in Fractured Rock Permeability in the Yucca Mountain Drift Scale Test. Proceedings (to be published), GeoProc2003, Stockholm, Sweden, October 2003. 

ANALYSIS OF STRESS AND MOISTURE INDUCED CHANGES IN FRACTURED ROCK PERMEABILITY AT THE YUCCA MOUNTAIN DRIFT SCALE TEST... 

The long-term performance of the repository at Yucca Mountain will be affected by the coupling of thermal, hydrological and chemical (THC) processes in the rock around the emplacement drifts. The transport of heat, fluid, and vapor will result in changes in water and gas chemistry, as well as mineral dissolution and precipitation which may lead to permanent changes in porosity, permeability and unsaturated hydrological properties. The purpose of this contribution is to describe the approach used to model reaction-transport processes in the Drift Scale Test (DST) with comparisons of simulation results to measured geochemical data on water, gas, and minerals. 

Abstract Modeling of the drift-scale heater test at the Exploratory Studies Facility at Yucca Mountain, Nevada, U.S.A. was performed. The objectives of the analysis were to investigate the (i) temperature effects on mechanical deformation surrounding the heated drift and (ii) thermal-mechanical effects on rock-mass permeability. The continuum representation of a deformation-permeability relationship based on fracture normal stress was developed to assess rock-mass permeability variations because of temperature changes. The estimated rock-mass displacements and permeability variations as a function of heating time were compared with field measurements. The estimated trend of permeability responses using a normal stress-based deformation-permeability relationship compared reasonably to that measured. 

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