PLAXIS LIQUEFACTION MODEL UBC3D-PLM - Knowledge Base

1.2Excess Pore Pressures\nitial Vertical Effective Stress1.00.80.60.40.2Experiment0.0UBC3D-PLM-0.20 2 4 6 8 10 12 14 16 18 20Num ber of CyclesFigure 2.4: Validation of UBC3D-PLM in cyclic loading. Evolution of theexcess pore pressure in Test 1. Fraser sand with RD = 40%. CSR = 0.08.investigated in the literature by Park and Byrne (2004). This limitation isalso presented in this version. In Figure 2.8 the accumulated pore pressurefrom the numerical predictions for Test 1 (CSR = 0.08) when K 0 equals 0.5is presented. The accuracy of the model is lower in this case, but the resultsare accepted for modelling such a complicated phenomenon.In Figure 2.9 and 2.10 the numerical calculations for Test 2 (CSR = 0.1)and 3 (CSR = 0.12) are presented respectively. The model gives higheraccuracy for these CSR compared to Test 1. A final observation in thepredicted soil behaviour after anisotropic consolidation which explains thefinal results, is that in the UBC3D-PLM when the stress path starts fromthe K 0 line and reaches the isotropic axis during loading, the primary yieldsurface with the initial value of plastic shear modulus is activated and themodel predicts a rapid increase to the excess pore pressure. The predictedsoil behaviour with the UBC3D-PLM during loading when the stress pathstarts from a K 0 different than 1 will be further improved in the next version.Finally, in Figure 2.11 a drained strain controlled cyclic direct simple28