TY - GEN
T1 - Modified triaxial apparatus for nonuniform loading beyond frictional ends
AU - Asmar, Randa
AU - Hashash, Youssef M.A.
PY - 2014
Y1 - 2014
N2 - Available laboratory testing devices are designed to generate uniform stress and strain states within a tested specimen. Accordingly, these devices provide information on material behavior within a narrow range of stress-strain paths and do not cover the loading conditions that occur in field problems. This limited information generally results in a constitutive model that may not be justifiable to represent loading conditions that differ substantially from the ones in laboratory tests. This paper presents the design of a newly developed next generation laboratory testing device that imposes nonuniform loading on a soil specimen beyond frictional ends. This device is integrated with an evolutionary inverse analysis computational engine to develop a soil constitutive model that reliably captures the soil behavior under general loading conditions. The design inherits features of the conventional triaxial test and adds frictional ends and lateral displacement restraint clamps. Numerical simulation showed that the sheared specimen with clamps includes shear modes that cannot currently be mobilized with available testing devices. The employed close-range digital photogrammetry system measures 3D lateral deformations at 0.5% axial strain or greater with a maximum error of about 2.5%.
AB - Available laboratory testing devices are designed to generate uniform stress and strain states within a tested specimen. Accordingly, these devices provide information on material behavior within a narrow range of stress-strain paths and do not cover the loading conditions that occur in field problems. This limited information generally results in a constitutive model that may not be justifiable to represent loading conditions that differ substantially from the ones in laboratory tests. This paper presents the design of a newly developed next generation laboratory testing device that imposes nonuniform loading on a soil specimen beyond frictional ends. This device is integrated with an evolutionary inverse analysis computational engine to develop a soil constitutive model that reliably captures the soil behavior under general loading conditions. The design inherits features of the conventional triaxial test and adds frictional ends and lateral displacement restraint clamps. Numerical simulation showed that the sheared specimen with clamps includes shear modes that cannot currently be mobilized with available testing devices. The employed close-range digital photogrammetry system measures 3D lateral deformations at 0.5% axial strain or greater with a maximum error of about 2.5%.
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U2 - 10.1061/9780784413272.068
DO - 10.1061/9780784413272.068
M3 - Conference contribution
AN - SCOPUS:84906836037
SN - 9780784413272
T3 - Geotechnical Special Publication
SP - 703
EP - 712
BT - Geo-Congress 2014 Technical Papers
PB - American Society of Civil Engineers
T2 - 2014 Congress on Geo-Characterization and Modeling for Sustainability, Geo-Congress 2014
Y2 - 23 February 2014 through 26 February 2014
ER -