Settlement of uranium mill tailings piles: a comparison of analysis techniques. [TRUNC code]
Two empirical methods of settlement analysis (Terzaghi's theory and a simplified version of the Fredlund-Morgenstern two-stress-state approach) were compared to the computer code TRUNC, a modified version of the TRUST code for variably saturated flow in deformable porous media. The three methods were used to predict settlement of a 12.2-m-deep pile of tailings slimes with a drain at the bottom. The simpler, empirical methods of settlement analysis were just as effective as TRUNC in predicting total settlement. For saturated tailings, predictions of total settlement by Terzaghi's theory and TRUNC were in close agreement (1.69 and 1.72 m, respectively). For partially saturated tailings, the simplified stress-state approach and TRUNC predicted similar total settlements (0.52 and 0.51 m, respectively). Terzaghi's theory, as applied, overestimated the time of settlement under saturated conditions (170 days versus 140 days predicted by TRUNC) because it did not account for gravitational gradients. No empirical or analytical means were available to predict the time of settlement under partially saturated conditions. The TRUNC code, however, predicted 1500 days (4.1 years) for settlement under partially saturated conditions. If the magnitude of partially saturated settlement is considered significant, then the time over which it occurs will most likely be the deciding factor in determining when to place the cover on the tailings pile. 19 references.
- Research Organization:
- Pacific Northwest Labs., Richland, WA (USA)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 5976086
- Report Number(s):
- NUREG/CR-3972; PNL-5222; ON: TI85007782
- Resource Relation:
- Other Information: Includes 2 sheets of 24x reduction microfiche
- Country of Publication:
- United States
- Language:
- English
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