Rock mass deformation properties of closely jointed basalt
The deformational behavior of the Columbia River basalt is being investigated as part of a comprehensive site characterization program intended to determine the feasibility of constructing a nuclear waste repository in basalt at Hanford, Washington. Direct field measurements were conducted in a 2-m cube of basalt to obtain truly representative rock mass deformation properties. Load was applied to the test block in three orthogonal directions through the use of flat jacks in two perpendicular planes and a cable anchor system in the third. This configuration allowed the block to be placed in a simulated triaxial stress state at stress levels up to 12.5 MPa. The deformation at the center of the test block was monitored through the use of an optical measurement system developed for this project. The results indicate that the vertically oriented columnar joints have a significant influence on the deformation behavior of the basalt. The modulus in the direction parallel to the column axis was approx. 30 GPa, while the modulus value perpendicular to the columns was approx. 20 GPa. Laboratory measurements of intact specimens taken from this area yielded a value of 80 GPa with no indication of anisotropy. Hysteresis was observed in all loading cycles, but was distinctly more pronounced perpendicular to the column axis, indicative of significant joint displacement in this direction. The results of this test represent the first true rock mass modulus data obtained in closely jointed rock on a large scale. These measurement methods have eliminated many of the ambiguities associated with borehole jacking and surface measurement techniques.
- Research Organization:
- Rockwell International Corp., Richland, WA (USA). Energy Systems Group
- DOE Contract Number:
- AC06-77RL01030
- OSTI ID:
- 6525545
- Report Number(s):
- RHO-BW-SA-267-P; ON: DE83006084
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
58 GEOSCIENCES
580300* -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
BASALT
DATA
DEFORMATION
EXPANSION
EXPERIMENTAL DATA
FEASIBILITY STUDIES
FEDERAL REGION X
GEOLOGIC DEPOSITS
HANFORD RESERVATION
HIGH-LEVEL RADIOACTIVE WASTES
HYSTERESIS
IGNEOUS ROCKS
INFORMATION
MANAGEMENT
MATERIALS
MECHANICAL PROPERTIES
MECHANICS
NATIONAL ORGANIZATIONS
NORTH AMERICA
NUMERICAL DATA
POISSON RATIO
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTES
ROCK MECHANICS
ROCKS
STRAINS
STRESSES
TEMPERATURE DEPENDENCE
THERMAL EXPANSION
UNDERGROUND DISPOSAL
US DOE
US ERDA
US ORGANIZATIONS
USA
VOLCANIC ROCKS
WASHINGTON
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES