Studies on the In-situ Soil Shear Apparatus (I)

Structure of the In-situ Soil Shear Apparatus and its Accuracy

Abstract

Importance of soil shear resistance to trafficabilities and performance of tractors, combines and other farming macshines, has been pointed out by several investigations in the past. And a few methods have been applied to determine the soil shearing force.
In this study, as to compare the traditional measuring result by standard shear head, five other shear heads with different type were used. Examined soil type were sand, sandy loam, clay and other.
The maximum shearing stress were calculated by using following formulas, in which the torque value was measured while the maximum soil resistance presented.
S₁=T₄/2/3π(r₁³-r₂³)+2πH(r₁²+r₂²)
S₂=T₃/2/3π(r₁³-r₂³)
In comparing with value S₁ and S₂ to maximum shearing stress value of direct shear test, it was presented that value S₂ was considered reasonable.