TY - JOUR
T1 - A Multidirectional Cyclic Direct Simple Shear Device for Characterizing Dynamic Soil Behavior
AU - Bhaumik, Lopamudra
AU - Rutherford, Cassandra J.
AU - Olson, Scott M.
AU - Hashash, Youssef M.A.
AU - Numanoglu, Ozgun A.
AU - Cerna-Diaz, Alfonso A.
AU - Weaver, Thomas
N1 - Support for this work was provided by the US Nuclear Regulatory Commission under award number NRC-HQ-12-C-04-0117. Neither the US government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party’s use, or the results of such use, of any information, apparatus, product, or process disclosed in this paper, or represents that its use by such third party would not infringe privately owned rights. The views expressed in this paper are not necessarily those of the US Nuclear Regulatory Commission.
PY - 2023/1/24
Y1 - 2023/1/24
N2 - 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), ϕ′peak-DSS was about 5° smaller than ϕ′peak-TC if the horizontal plane is considered the failure plane, whereas ϕ′peak-DSS ≈ ϕ′peak-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.
AB - 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), ϕ′peak-DSS was about 5° smaller than ϕ′peak-TC if the horizontal plane is considered the failure plane, whereas ϕ′peak-DSS ≈ ϕ′peak-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.
KW - bender element
KW - constant volume
KW - earthquake
KW - friction angle
KW - laboratory testing
KW - multidirectional direct simple shear
KW - sand
KW - shear wave velocity
KW - volumetric strain
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U2 - 10.1520/GTJ20210286
DO - 10.1520/GTJ20210286
M3 - Article
AN - SCOPUS:85148327155
SN - 0149-6115
VL - 46
JO - Geotechnical Testing Journal
JF - Geotechnical Testing Journal
IS - 2
ER -