TY - JOUR
T1 - Evaluation of a simplified soil constitutive model considering implied strength and pore-water pressure generation for one-dimensional (1d) seismic site response
AU - Mei, Xuan
AU - Olson, Scott M.
AU - Hashash, Youssef M.A.
N1 - Publisher Copyright:
© 2019 Canadian Science Publishing. All right reserved.
PY - 2020
Y1 - 2020
N2 - Pore-water pressure (PWP) generation can lead to soil softening and liquefaction of sandy soils during earthquakes, with potential influence on site response and seismic design. The authors evaluated the generalized quadratic/hyperbolic (GQ/H) constitutive model, which captures small-strain stiffness, large-strain shear strength, and is coupled with a widely used cyclic strain–based PWP generation model (termed GQ/H+u). A suite of cyclic direct simple shear tests with a range of relative densities (~30%–80%) and effective vertical stresses (~25–200 kPa) and dynamic centrifuge tests with liquefiable sands were used to evaluate the ability of the GQ/H+u model to simulate cyclic soil behavior. Results indicate that GQ/H+u provides reasonable estimates of PWP increase during cyclic shear, with differences between measured and computed excess PWP ratios (ru) for both element and centrifuge tests generally smaller than 0.1. Computed spectral accelerations are comparable to centrifuge test measurements, with almost no bias at medium to long periods (T > 0.4 s) when the computed maximum shear strain (γmax) was smaller than the limit shear strain (γLimit). When computed ru > 0.8 and computed γmax > γLimit, spectral accelerations may be underestimated at both short and long periods as dilative behavior is not captured by GQ/H+u.
AB - Pore-water pressure (PWP) generation can lead to soil softening and liquefaction of sandy soils during earthquakes, with potential influence on site response and seismic design. The authors evaluated the generalized quadratic/hyperbolic (GQ/H) constitutive model, which captures small-strain stiffness, large-strain shear strength, and is coupled with a widely used cyclic strain–based PWP generation model (termed GQ/H+u). A suite of cyclic direct simple shear tests with a range of relative densities (~30%–80%) and effective vertical stresses (~25–200 kPa) and dynamic centrifuge tests with liquefiable sands were used to evaluate the ability of the GQ/H+u model to simulate cyclic soil behavior. Results indicate that GQ/H+u provides reasonable estimates of PWP increase during cyclic shear, with differences between measured and computed excess PWP ratios (ru) for both element and centrifuge tests generally smaller than 0.1. Computed spectral accelerations are comparable to centrifuge test measurements, with almost no bias at medium to long periods (T > 0.4 s) when the computed maximum shear strain (γmax) was smaller than the limit shear strain (γLimit). When computed ru > 0.8 and computed γmax > γLimit, spectral accelerations may be underestimated at both short and long periods as dilative behavior is not captured by GQ/H+u.
KW - DEEPSOIL
KW - Effective stress analysis
KW - Liquefaction
KW - Pore-water pressure generation
KW - Site response analysis
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U2 - 10.1139/cgj-2018-0893
DO - 10.1139/cgj-2018-0893
M3 - Article
AN - SCOPUS:85075831381
SN - 0008-3674
VL - 57
SP - 974
EP - 991
JO - Canadian Geotechnical Journal
JF - Canadian Geotechnical Journal
IS - 7
ER -