A large diameter (d=300 mm) Cyclic Simple Shear device, or as we call her, LACSI, is operational and actively being used for testing all kinds of large particle soil specimens. Currently tests are being conducted on mine spoils from South America and gravelly soils from New Zealand and the US. The device has also previously been used to test, Municipal Solid Waste, Hazardous Waste and other materials with oversized particles.

LACSI is a prototype device that was developed at the University of Michigan in collaboration with Geocomp and is now part of the UC Berkeley Geotechnical laboratories. It was installed and calibrated during the summer of 2020 and has been used since then.

The device allows for testing of specimens up to 300 mm in diameter and up to 127 mm in height. It can execute tests at vertical stresses of nearly 600 kPa under constant load or constant volume conditions, at dry, moist, or submerged states. Shearing can be displacement- or load-controlled. Two 10-kip load cells are used to measure the vertical and horizontal loads and displacement transducers are used to measure the vertical and horizontal displacements. The device can also be used for large size direct shear or interface shear testing. Testing can include monotonic and cyclic simple shear for estimating undrained strength, stiffness assessment and liquefaction behavior of coarse-grained materials.

In addition, the device is equipped with accelerometers and bender elements that allow for the measurement of shear wave velocity of the tested specimen prior, and in some cases during, shearing.

Click here to see an example test datasheet from last week on a gravelly soil.

A paper, published in the ASTM Journal of Geotechnical Testing, describes this prototype device:

Zekkos, D., Athanasopoulos-Zekkos, A., Hubler, J., Fei, X., Zehtab, K. H., Marr, W. A. (2017) “Development of a large-size cyclic direct simple shear device for characterization of ground materials with oversized particles”, ASTM Geotechnical Testing Journal, March 2018 Volume 41 (2), 263-279, DOI: 10.1520/GTJ20160271.

Additional published papers using this device, available on demand, or through our intranet, include:

• Basham, M., Athanasopoulos-Zekkos, A., Zekkos, D. (2019) “The importance of vertical displacement control during constant volume cyclic simple shear testing, 7th International Conference on Earthquake Geotechnical Engineering, Rome, Italy, June 17-20 2019.
• Fei, X., & Zekkos, D. (2018). Cyclic Simple Shear Testing of Degraded Municipal Solid Waste from California Under Constant Volume and Constant Load Conditions. In 8th International Congress on Environmental Geotechnics (pp. 35-42). 28 October – 1 November 2018, Springer, Singapore.
• Hubler, J. F., Athanasopoulos-Zekkos, A., & Zekkos, D. (2018). Monotonic and cyclic simple shear response of gravel-sand mixtures. Soil Dynamics and Earthquake Engineering, 115, 291-304.
• Hubler, J.F., Athanasopoulos-Zekkos, A. and Zekkos, D. (2018). “Post-Liquefaction Volumetric Strain of Gravel-Sand Mixtures in Constant Volume Simple Shear.” Geotechnical Earthquake Engineering and Soil Dynamics V, June 10-13 2018, Austin, TX.
• Hubler, J.F., Athanasopoulos-Zekkos, A. and Zekkos, D. (2018) “Evaluation of Post-Liquefaction Shear Strength and Shear Wave Velocity of Uniform Gravels.” International Foundations Congress and Equipment Expo, Orlando, March 5-10, 2018.
• Hubler, J.F., Athanasopoulos-Zekkos, A. and Zekkos, D. (2018) “Evaluation of Post-Liquefaction Shear Strength and Shear Wave Velocity of Uniform Gravels.” International Foundations Congress and Equipment Expo, Orlando, March 5-10, 2018.
• Fei, X., Zekkos, D. (2017), “Comparison of Direct Shear and Simple Shear Response of MSW”, Environmental Geotechnics Journal, September 2017, DOI: 10.1680/jenge.16.00036.
• Hubler, J., Athanasopoulos-Zekkos, A., Zekkos, D. (2017). “Monotonic, Cyclic and Post-Cyclic Simple Shear Behavior of Three Uniform Gravels.” Journal of Geotechnical and Geoenvironmental Engineering, 143(9), September 2017. DOI: http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0001723. Editor’s Choice paper in October 2017.
• Hubler, J., Athanasopoulos-Zekkos, A., and Zekkos, D. (2017) “Pore Pressure Generation of Pea Gravel, Sand, and Gravel-Sand Mixtures in Constant Volume Simple Shear”, 3rd International Conference on Performance-Based Design for Earthquake Geotechnical Engineering, Vancouver, BC, Canada, July 17-19, 2017.
• Zekkos, D., Fei, X. (2016). “Comparison of Constant Load and Constant Volume Shearing Response in Simple Shear Testing of Municipal Solid Waste.” Waste Management, http://dx.doi.org/10.1016/j.wasman.2016.09.029.
• Fei, X., Zekkos, D. (2015). "Large-size controlled degradation and simple shear testing of municipal solid waste from Michigan", XVI European Conference on Soil Mechanics and Geotechnical Engineering, 13-17 September 2015, Edinburg'