Determination of undisturbed soil shear strength using a torsional shear annulus
Subject Areas :
Keywords: Cohesion, internal friction angle, soil shearing, torsional torque,
Abstract :
Determination of undisturbed soil shear strength using a torsional shear annulus IimanAhmadi1 1- Assistant professor of Mechanics of Agricultural Machinery, Department of Agronomy, Islamic Azad University, Isfahan (Khorasgan) Branch, Isfahan, Iran. Corresponding author email: i_ahmadi_m@yahoo.com Received: 1 April 2018 Accept:20 July 2018 Abstract It is important to have accurate information about shear strength parameters of soil in order to analyze some topics of the soil mechanics. On the other hand, if these parameters are obtained using some undisturbed soil samples, the presented analysis will be more compatible with reality. The aim of this study is to design, analyze theoretically, fabricate and evaluate a simple torsional shear annulus for measuring parameters of the undisturbed soil shear strength. The other aim of this study is to inspect which of the two assumptions about soil shear stress distribution (i.e. uniform stress distribution and linear stress distribution) is able to measure shear strength parameters of soil accurately. According to the results of this study, if soil moisture content reduces, both of the strength parameters will increase. On the other hand, comparison of the average values of error percentages obtained for the calculation of soil cohesion (i.e. ) and soil internal friction angle (i.e. ) shows that the assumption of linear shear stress distribution has resulted in less error percentages in comparison with the assumption of uniform shear stress distribution. Therefore, required calculations for obtaining shear strength parameters from the fabricated apparatus should be carried out based on the assumption of linear shear stress distribution. Keywords: cohesion, internal friction angle, soil shearing, torsional torque
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