ANALYSIS FOR THE DEFORMATION OF THE DAMAGED EMBANKMENTS DURING THE 2004 NIIGATAKEN-CHUETSU EARTHQUAKE BY USING STRESS-STRAIN CURVES OF LIQUEFIED SANDS OR SOFTENED CLAYS

摘要

Stress-strain curves of liquefied sands and softened clays were obtained by cyclic torsional shear tests. In the tests, 20 cycles of loadings were applied at first then a monotonic loading was applied. Shear modulus of the liquefied sands or softened clays, G_1, was evaluated based on the stress-strain curves during the monotonic loading. Then, a relationship among cyclic stress ratio to cause 7.5 percent of double amplitude of shear strain, R_L(gamma_(DA) = 7.5 percent, N_L=20), severity of liquefaction, F_L and G_1/sigma_c' were derived. Based on the relationship, analysis for the deformation of damaged road embankment during the 2004 Niigataken-chuetsu earthquake, was conducted. Analyzed deformation was fairly coincided with the measured deformation.