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Full-Text Articles in Geological Engineering

Effects Of Soil Aggregates On Debris-Flow Mobilization: Results From Ring-Shear Experiments, Neal R. Iverson, Janet E. Mann, Richard M. Iverson Jun 2010

Effects Of Soil Aggregates On Debris-Flow Mobilization: Results From Ring-Shear Experiments, Neal R. Iverson, Janet E. Mann, Richard M. Iverson

Geological and Atmospheric Sciences Publications

Rates and styles of landslide motion are sensitive to pore-water pressure changes caused by changes in soil porosity accompanying shear deformation. Soil may either contract or dilate upon shearing, depending upon whether its initial porosity is greater or less, respectively, than a critical-state porosity attained after sufficiently high strain. We observed complications in this behavior, however, during rate-controlled (0.02 m s− 1) ring-shear experiments conducted on naturally aggregated dense loamy sand at low confining stresses (10.6 and 40 kPa). The aggregated soil first dilated and then contracted to porosities less than initial values, whereas the same soil with ...


Scaled Experimental Study On Excavation Of Lunar Regolith With Rakes/Rippers And Flat Blade, Masafumi Iai Jan 2010

Scaled Experimental Study On Excavation Of Lunar Regolith With Rakes/Rippers And Flat Blade, Masafumi Iai

Doctoral Dissertations

"As humanity's activities expand to the Moon, Mars, and other extra-terrestrial bodies, it will be necessary to use local resources rather than bringing everything from the Earth. This concept is called In-Situ Resource Utilization (ISRU), which starts with excavation and earthmoving. The present study focuses on loosening and moving of the lunar regolith by a ripper (or rake) and a wide blade with consideration of gravel content. After characterizing the lunar regolith and two of its simulants (JSC-1A and FJS-1), the relationship between the excavation energy and different conditions, namely gravel content, relative density, and tine spacing on a ...