Nonlinear dynamic finite element simulations are used to study field case histories of Japanese levees shaken by past earthquakes. The Ministry of Land, Infrastructure, Transport, and Tourism (MLIT) in Japan instrumented various levees with ground motion sensors, and in one case a piezometer, and inspected the levees for damage following a series of earthquakes for which recordings are available. In this study, these levees are analyzed using finite element simulations in OpenSees using constitutive models capable of capturing liquefaction effects combined with an element formulation that models groundwater flow. Measured and predicted responses are compared, including (1) the pseudo acceleration response spectrum for the horizontal motion of the levee crest, (2) pore pressures in a sand layer that exhibited liquefaction, and (3) permanent levee crest settlement. Small-strain levee response was first calibrated using the recorded response from earthquakes with small amplitude. We then moved forward with analysis of larger ground motions. Predictions of crest settlement agree reasonably well with observations, with significant damage predicted correctly. However, settlements larger than 1 cm are predicted for a number of motions for which no damage was reported. It is unclear whether these are over-predictions, or whether settlements larger than 1 cm may have gone undetected in post-earthquake inspections. This study provides validation that nonlinear effective stress analyses are capable of predicting levee deformations due to soil liquefaction, and may therefore play an important role in future assessments of the seismic response of levee systems.
Validation of Analysis Using Case Histories of Japanese Levees
Zimmaro P.;
2023-01-01
Abstract
Nonlinear dynamic finite element simulations are used to study field case histories of Japanese levees shaken by past earthquakes. The Ministry of Land, Infrastructure, Transport, and Tourism (MLIT) in Japan instrumented various levees with ground motion sensors, and in one case a piezometer, and inspected the levees for damage following a series of earthquakes for which recordings are available. In this study, these levees are analyzed using finite element simulations in OpenSees using constitutive models capable of capturing liquefaction effects combined with an element formulation that models groundwater flow. Measured and predicted responses are compared, including (1) the pseudo acceleration response spectrum for the horizontal motion of the levee crest, (2) pore pressures in a sand layer that exhibited liquefaction, and (3) permanent levee crest settlement. Small-strain levee response was first calibrated using the recorded response from earthquakes with small amplitude. We then moved forward with analysis of larger ground motions. Predictions of crest settlement agree reasonably well with observations, with significant damage predicted correctly. However, settlements larger than 1 cm are predicted for a number of motions for which no damage was reported. It is unclear whether these are over-predictions, or whether settlements larger than 1 cm may have gone undetected in post-earthquake inspections. This study provides validation that nonlinear effective stress analyses are capable of predicting levee deformations due to soil liquefaction, and may therefore play an important role in future assessments of the seismic response of levee systems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
