A Multidirectional Cyclic Direct Simple Shear Device for Characterizing Dynamic Soil Behavior

Lopamudra Bhaumik, Cassandra J Rutherford, Scott M. Olson, Youssef M.A. Hashash, Ozgun A. Numanoglu, Alfonso A. Cerna-Diaz, Thomas Weaver

Research output: Contribution to journalArticlepeer-review


A newly constructed multidirectional cyclic direct simple shear (mcDSS) device with unique capabilities is introduced. This mcDSS apparatus, called the Illinois mcDSS (or I-mcDSS) device, for the first time brings together the following capabilities: (1) servo-hydraulic control that can apply stress- or strain-based monotonic, cyclic (e.g., sinusoidal, saw tooth, and square), and high-frequency broadband loads at realistic earthquake loading rates, improving over previous devices with pneumatic control; (2) unidirectional and bidirectional loading; (3) bender elements to measure (S-wave) velocity; (4) a cell for applying consolidation stresses different from at-rest values as well as back-pressure saturation; and (5) a multidirectional load cell on top of the specimen to minimize the effect of compliance and component friction on load measurements. The I-mcDSS device tests cylindrical specimens confined using either a wire-reinforced membrane or stacked rings. Experiments conducted on a uniformly graded Ottawa sand are presented to illustrate each key I-mcDSS feature. Test repeatability is demonstrated for monotonic and bidirectional cyclic tests. Drained or constant volume, K0-consolidated, strain-controlled monotonic, unidirectional cyclic, and bidirectional (circular, figure-8, and broadband) cyclic tests on dry specimens yielded shear stress-shear strain relations, peak effective-stress friction angles (ϕ′peak-DSS), and volumetric strains, or excess pore water pressures, consistent with the literature. However, depending on load cell and displacement transducer locations, device compliance was observed to affect shear stress-shear strain response at shear strains less than 1 %. When compared with triaxial compression (TC) peak effective-stress friction angles (ϕ′peak-TC), ϕpeak-DSS was about 5° smaller than ϕpeak-TC if the horizontal plane is considered the failure plane, whereas ϕpeak-DSS ≈ ϕpeak-TC if the horizontal plane is considered the plane of maximum shear stress. Lastly, measured S-wave velocities at varying confinements are consistent with published correlations.

Original languageEnglish (US)
JournalGeotechnical Testing Journal
Issue number2
StatePublished - Jan 24 2023


  • bender element
  • constant volume
  • earthquake
  • friction angle
  • laboratory testing
  • multidirectional direct simple shear
  • sand
  • shear wave velocity
  • volumetric strain

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology


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