• condensation;
  • evaporation;
  • fractured rock;
  • microclimate;
  • monitoring techniques;
  • tunnels


Understanding microclimate dynamics in tunnels is important for designing, operating, and maintaining underground facilities. For example, for the geological disposal of radioactive materials, condensation of vapour should be minimized as liquid water can accelerate waste package corrosion and radionuclide release. While microclimate dynamics are known to be dominated by the advection of heat and moisture, additional factors may also be important, such as the presence of fractures or faults. We present data collected using a relatively inexpensive method that is under development to assess microclimatic perturbations underground. By combining standard temperature and relative humidity sensors with low-cost sensors designed to detect changes in water content, we were able to infer microclimate dynamics along a tunnel at the proposed geological repository at Yucca Mountain, Nevada. We observed significant differences in the pattern of condensation in a faulted zone relative to that of a non-faulted zone, suggesting that hydrogeologic features have to be accounted for when evaluating the microclimate dynamics of excavated cavities in fractured, partially saturated rocks. Published in 2008 by John Wiley & Sons, Ltd.