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Debris-flow deposition: Effects of pore-fluid pressure and friction concentrated at flow margins

Geological Society of America Bulletin

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Abstract

Measurements of pore-fluid pressure and total bed-normal stress at the base of several ???10 m3 experimental debris flows provide new insight into the process of debris-flow deposition. Pore-fluid pressures nearly sufficient to cause liquefaction were developed and maintained during flow mobilization and acceleration, persisted in debris-flow interiors during flow deceleration and deposition, and dissipated significantly only during postdepositional sediment consolidation. In contrast, leading edges of debris flows exhibited little or no positive pore-fluid pressure. Deposition therefore resulted from grain-contact friction and bed friction concentrated at flow margins. This finding contradicts models that invoke widespread decay of excess pore-fluid pressure, uniform viscoplastic yield strength, or pervasive grain-collision stresses to explain debris-flow deposition. Furthermore, the finding demonstrates that deposit thickness cannot be used to infer the strength of flowing debris.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Debris-flow deposition: Effects of pore-fluid pressure and friction concentrated at flow margins
Series title:
Geological Society of America Bulletin
Volume
111
Issue:
10
Year Published:
1999
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
1424
Last page:
1434
Number of Pages:
11