Shape and dynamics of seepage erosion in a horizontal granular bed

Journal Article · Wed Oct 10 00:00:00 EDT 2012 · Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics

DOI:https://doi.org/10.1103/physreve.86.041304· OSTI ID:1505725

Berhanu, Michael ^[1]; Petroff, Alexander ^[2]; Devauchelle, Olivier ^[3]; Kudrolli, Arshad ^[4]; Rothman, Daniel H. ^[2]

---

1. Clark Univ., Worcester, MA (United States); Centre National de la Recherche Scientifique (CNRS), Paris (France)
2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
3. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Centre National de la Recherche Scientifique (CNRS), Paris (France)
4. Clark Univ., Worcester, MA (United States)

We examine erosion patterns observed in a horizontal granular bed resulting from seepage of water motivated by observation of beach rills and channel growth in larger scale land forms. Our experimental apparatus consists of a wide rectangular box filled with glass beads with a narrow opening in one of the side walls from which eroded grains can exit. Quantitative data on the shape of the pattern and erosion dynamics are obtained with a laser-aided topography technique.We report that the spatial distribution of the source of groundwater can significantly impact the shape of observed patterns. An elongated channel is observed to grow upstream when groundwater is injected at a boundary adjacent to a reservoir held at constant height. An amphitheater (semicircular) shape is observed when uniform rainfall infiltrates the granular bed to maintain a water table. Bifurcations are observed as the channels grow in response to the groundwater. We further find that the channels grow by discrete avalanches as the height of the granular bed is increased above the capillary rise, causing the deeper channels to have rougher fronts. The spatiotemporal distribution of avalanches increase with bed height when partial saturation of the bed leads to cohesion between grains. Yet, the overall shape of the channels is observed to remain unaffected indicating that seepage erosion is robust to perturbation of the erosion front.

• Research Organization: Clark Univ., Worcester, MA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: FG02-02ER15367
• OSTI ID: 1505725
• Alternate ID(s): OSTI ID: 1101580
• Journal Information: Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics, Vol. 86, Issue 4; ISSN 1539-3755
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES