Measuring and modeling water imbibition into tuff
Yucca Mountain (Nevada) is being investigated as a potential site for a high-level-radioactive-waste repository. The site combines a partially saturated hydrologic system and a stratigraphy of fractured, welded and nonwelded tuffs. The long time scale for site hydrologic phenomena makes their direct measurement prohibitive. Also, modeling is difficult because the tuffs exhibit widely varying, and often highly nonlinear hydrologic properties. To increase a basic understanding of both the hydrologic properties of tuffs and the modeling of flow in partially saturated regimes, the following tasks were performed, and the results are reported: (1) Laboratory Experiment: Water imbibition into a cylinder of tuff (taken from Yucca Mountain drill core) was measured by immersing one end of a dry sample in water and noting its weight at various times. The flow of water was approximately one-dimensional, filling the sample from bottom to top. (2) Computer Simulation: The experiment was modeled using TOSPAC (a one-dimensional, finite-difference computer program for simulating water flow in partially saturated, fractured, layered media) with data currently considered for use in site-scale modeling of a repository in Yucca Mountain. The measurements and the results of the modeling are compared. Conclusions are drawn with respect to the accuracy of modeling transient flow in a partially saturated, porous medium using a one-dimensional model and currently available hydrologic-property data.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States); Spectra Research Inst., Albuquerque, NM (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 60017
- Report Number(s):
- SAND--86-1757C; CONF-861220--3; ON: DE87005855
- Country of Publication:
- United States
- Language:
- English
Similar Records
Evaluation of measurement scale using imbibition experiments in volcanic tuffs
The role of fracture coatings on water imbibition into unsaturated tuff