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Your search keyword '"Stadler, Alan T."' showing total 6 results
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6 results on '"Stadler, Alan T."'

1. Erosion and stability of a mine soil

Author

Wu, Tien H., Stadler, Alan T., and Low, Chin-wah

Subjects
Mine soils -- Research, Erosion -- Research, Sedimentation and deposition -- Research, Earth sciences, Engineering and manufacturing industries
Abstract

Mine soils developed from mine spoils commonly have a wide range of particle size. The slopes of old spoil piles usually are marked by gullies due to years of uncontrolled erosion. These characteristics raise questions about applicability of available theories and models for estimating runoff and erosion. An investigation was made to determine whether available erosion models can work for mine soils and can account for gully erosion. The investigation at an abandoned surface mine consisted of measurement of soil and sediment properties, measurement of runoff and erosion, observations of armor by rock fragments on gully floor, and calculations with available theories of sediment transport and slope stability. The results at this site suggest that (1) predictions with the ANSWERS model have about the same accuracy as those made for agricultural lands; (2) armor provided by rock fragments are temporary as they are periodically removed by debris flows; (3) detachment by rainfall impact is the primary cause of erosion on short steep slopes; and (4) a simplified method can be used for estimating erosion on such slopes.

Published
1996

2. Geogrid reinforcement of Piedmont residual soil

Author

Stadler, Alan T. and Stadler, Alan T.

Subjects
Retaining walls Research North Carolina., Geosynthetics Research North Carolina., Murs de soutènement Recherche Caroline du Nord., Géosynthétiques Recherche Caroline du Nord., Residual soils., Backfill soils., Composite materials., North Carolina.
Abstract

Soil-geosynthetic composites such as those used in mechanically stabilized earth (MSE) retaining walls are experiencing widespread use, particularly in transportation applications. The potential economic benefit of using "lower-quality" on-site material in MSE retaining wall applications is substantial. An experimental research program investigating soil-geosynthetic interaction was performed at the University of North Carolina at Charlotte. To study this composite behavior, the research program employed a large pullout box equipped with state-of-the-art electronic instrumentation and data acquisition. The interaction of two "lower quality" piedmont residual soils (A-2-4 and A-4) with four representative, geosynthetic reinforcement materials (rigid geogrid, flexible geogrid, high strength geotextile, and medium strength geotextile) was examined through a series of anchorage strength tests. Through these tests, insight into the load versus deformation behavior of the reinforcing materials embedded in piedmont residuum was obtained. This report describes the test methodology and presents test results.

Published
2001

6. Application of a Geocentrifuge and Sterolithographically Fabricated Apertures to Investigations of Multiphase Flow in Complex Fracture Apertures

Author

Stadler, Alan T., Stoner, Daphne L., Stedtfeld, Robert D., Meakin, Paul, and McCreery, Glenn E.

Abstract

A geotechnical centrifuge was used to investigate unsaturated multiphase fluid flow in synthetic fracture apertures under a variety of flow conditions. The geocentrifuge subjected the fluids to centrifugal forces allowing the Bond number to be systematically changed without adjusting the fracture aperture or the fluids. The fracture models were based on the concept that surfaces generated by the fracture of brittle geomaterials have a self-affine fractal geometry. The synthetic fracture surfaces were fabricated from a transparent epoxy photopolymer using sterolithography, and fluid flow through the transparent fracture models was monitored by an optical image acquisition system. Aperture widths were chosen to be representative of the wide range of geological fractures in the vesicular basalt that lies beneath the Idaho National Laboratory (INL). Transitions between different flow regimes were observed as the acceleration was changed under constant flow conditions. The experiments showed the transition between straight and meandering rivulets in smooth walled apertures (aperture width = 0.508 mm), the dependence of the rivulet width on acceleration in rough walled fracture apertures (average aperture width = 0.25 mm), unstable meandering flow in rough walled apertures at high acceleration (20 g) and the narrowing of the wetted region with increasing acceleration during the penetration of water into an aperture filled with wetted particles (0.875 mm diameter glass spheres).

Published
2005
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