A Similitude Study of the Slip-Sinkage Phenomenon of Grousered Plates (I)

Abstract

This study was conducted to analyze by application of similitude theory the slip-sinkage phenomenon in a clay soil using grousered plates. Seven unpowered rectangular grousered plates were designed with propotional lengths based on similitude model theory.
Fifteen variables were arranged into dimensionless pi terms according to the Buckingham Pi Theorem:
Z/y and H/pl²=F(b/l, h/l, λ/l, y/l, v²/gl, α, c/p, c/dl, φ)
for set 1, and
Z/y and H/pl²=(b/l, h/l, λ/l, y/l, v²/gl, α, q/p, q/dl)
for set 2.
The tests were conducted on a movable soil bin in the Model Tillage Laboratory of the Department of Agricultural Engineering, Iowa State University.
The conclusions are the following:
Slip-sinkage increased as vertical pressure increased, but was not signiificantly affected by the rate of slip.
The correlation between sinkage Z and distance of horizontal movement y was shown in the following equatcon: Z=Kl^uy^l-u (K and u are constant, 0<u<1) Sinkage in soft clay was larger than in hard clay soil, but slip-sinkage in soft clay was less significant than in clay soil.
The draft pi term H/pl² increased slightly as the slip rate increased, but was not significantly affected by the variation of vertical pressure.
The correlation between the distortion factor (β=π_9m/π₉) and the prediction factors (δ_s=π_1a/π_1am, δ_a=π_1b/π_1bm) are shown in the following equations (Table 9.)
δ_s=β^1.46 when π₆=0.00073, π₈=0.70
δ_s=β^0.442 π₆=0.00073, π₈=0.35
δ_a=β^0.434 π₆=0.00073, π₈=0.35
δ_a=β^0.181 π₆=0.00073, π₈=0.18
and so on.