GCE Research: Direct Shear Variability

Direct Shear Variability

Direct shear variability refers to the differences in the shear strength of rock or soil when tested, due to natural variations like mineral composition, grain size, and moisture content. This variability is critical for assessing the stability of slopes and excavations, helping to predict failure zones and design effective support systems to ensure safety and efficiency in mining operations.

Project Description

Direct shear test results play an important role in open pit and underground mine design. The mining geotechnical community has observed significant variability in the results of direct shear tests performed on identical or similar materials. This project focuses on quantifying the variability in direct shear test results and understanding how testing methodologies and data interpretation impact those results, with the ultimate aim of providing guidelines for a more uniform approach to determining the shear strength of natural fractures. 

Study Design

The study was broken into two phases based on discussions with the GCE’s membership group, technical advisors, stakeholders, and our internal research teams. The phase currently underway assesses the variability introduced by differing methods of interpretation of direct shear test results and associated corrections and conversions. Phase 2 will investigate the impact of testing equipment and protocols on variability of results.

 

Assessing the Variability in Direct Shear Testing Interpretation for Sets of Natural Fractures. 
Franco, M.A., Potter, J., Meyer, B. (2024, June). Assessing the variability in direct shear testing interpretation for sets of natural fractures [Paper presentation]. 58th US Rock Mechanics / Geomechanics Symposium, 2024, Golden, Colorado. 

Quantifying the Variability in Interpretation of Shear Testing of a Natural Fracture. 
Franco, M.A., Potter, J., Ross, B.J. (2023, June). Quantifying the variability in interpretation of shear testing of a natural fracture [Paper presentation]. 57th US Rock Mechanics/Geomechanics Symposium, 2023, Atlanta, Georgia.

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