DEFORMATION AND FORCE CHARACTERISTICS CAUSED BY INCLINED TINES IN LOAM SOIL WITH MOISTURE CONTENT BELOW LIQUID LIMIT

Abstract

Deformation and force characteristics caused by flat rigid tines (inclined at an angle of 50° to the horizontal soil surface) in loam soil with moisture content below the liquid limit were studied using a glass-sided soil bin. The tines moved in the soil bin in a quasi-static speed and the soil deformation was observed through the glass side of the soil bin. Strain gauge bonded L- shaped force transducers were used in recording soil forces. Three moisture content levels (viz 5.2%, 21% and 33.5% (d.b.)) were used. The results obtained indicated that soil deformation and force characteristics for loam soils are greatly affected by variations in soil moisture content. For 5.2% and 21% soil moisture contents, deformation patterns were progressive shear types. Soil forces for these moisture content levels were cyclic in nature and generally did not differ in magnitude. The deformation process was in regular cycles resulting in corresponding periodic variations in the soil reactions on the tines. There were no distinct zones as described in the passive soil pressure theory. Plastic type of soil deformation was observed in 33.5% soil moisture content with comparative high corresponding soil forces whose periodicity died off.