A Simple Device for in-situ Direct Shear and Sinkage Tests

Authors: A. Jerves, H. Ling, J. Gabaldon, M. Usoltceva, C. Coust´e, A. Agarwal, R. Hurley, J. Andrade

Abstract:

This work introduces a simple device designed to perform in-situ direct shear and sinkage tests on granular materials as sand, clays, or regolith. It consists of a box nested within a larger box. Both have open bottoms, allowing them to be lowered into the material. Afterwards, two rotating plates on opposite sides of the outer box will rotate outwards in order to clear regolith on either side, providing room for the inner box to move relative to the plates and perform a shear test without the resistance of the surrounding soil. From this test, Coulomb parameters, including cohesion and internal friction angle, as well as, Bekker parameters can be inferred. This device has been designed for a laboratory setting, but with few modifications, could be put on the underside of a rover for use in a remote location. The goal behind this work is to ultimately create a compact, but accurate measuring tool to put onto a rover or any kind of exploratory vehicle to test for regolith properties of celestial bodies.

Keywords: Simple shear, friction angle, Bekker parameters, device, regolith.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1099884

References:

[1] R. Sullivan, R. Anderson, J. Biesiadecki, T. Bond, and H. Stewart. ”Cohesions, Friction Angles, and Other Physical Properties of Martian Regolith from Mars Exploration Rover Wheel Trenches and Wheel Scuffs.” Journal of Geophysical Research 116.E2 (2011): n. pag. Print.
[2] Bekker, Mieczysaw Gregory. Theory of Land Locomotion. Ann Arbor: Univ. of Michigan Pr. 1956. Print
[3] Das, Braja M. Principles of Geotechnical Engineering. Pacific Grove, CA: Brooks Cole/Thompson Learning 2002, Print
[4] Borja, Ronaldo I. Plasticity, Modeling and & Computation. New York, NY: Springer-Verlag/Berlin-Heidelberg 2013, Print
[5] Rashidi, Majid, and Keyvan Seyfi. ”Comparative Studies on Bekker and Upadhyaya Models for Soil Pressure-Sinkage Behavior Prediction.” American-Eurasian Journal of Agricultural & Environmental Sciences. 3.1 (2008): 19-25. Print.
[6] Bardet, Jean P. Experimental Soil Mechanics. Upper Saddle River, NJ: Prentice-Hall, Inc. 1997, Print