Major, J. J.; Iverson, R. M.; McTigue, D. F.; Macias, S.; Fiedorowicz, B. K. 1997. Geotechnical properties of debris-flow sediments and slurries. In: Chen, Cheng-lung, ed. Debris-flow hazards mitigation: mechanics, prediction, and assessment: Proceedings of first international conference; 1997 August 7-9; San Francisco, CA. New York, NY: American Society of Civil Engineers: 249-259.
Measurements of geotechnical properties of various poorly sorted debris-flow sedimentsand slurries (s 32 mm diameter) emphasize their granular nature, and reveal that propertiesof slurries can differ significantly from those of compacted sediments. Measurements showthat: (1) cohesion probably offers little resistance to shear in most debris flows under lowconfining stresses normally found in nature; (2) intrinsic hydraulic permeabilities ofcompacted debris-flow sediments vary from about 10-14-10-9 permeabilities of "typical"debris-flow slurries fall toward the low end of the range; (3) debris-flow slurries arecharacterized by very large values of "elastic" compressibility (C-10-2 kPa-1); and (4)hydraulic diffusivities of quasistatically consolidating slurries are —10-4-10-7 m2/s. Lowhydraulic diffusivity of debris slurries permits excess fluid pressure and low effective strengthto persist during sediment transport and deposition.