# Calibration of Finn Model and UBSCAN Model for Simplified Liquefaction Analysis Procedures
## 5 Conclusions  
Soil-liquefaction-related hazards can damage structures via different mechanisms. In practice, the occurrence of soil liquefaction on a site is evaluated by a simplified liquefaction analysis procedure. Then, the damage of structures due to liquefaction hazards and the effectiveness of mitigation plans are explored by numerical simulation. Therefore, the liquefaction constitutive model used in numerical simulation should have a liquefaction resistance that is consistent with the simplified liquefaction analysis procedure in order to obtain reasonable and comparable evaluation results. In this study, the Finn model and the UBCSAND model were calibrated by fitting liquefaction triggering curves of four simplified liquefaction analysis procedures (NCEER, HBF, JRA96, and T-Y procedures). The calibration results are summarized as follows:  
1. The Finn model was not capable of modeling the banana-shaped stress-strain path and the butterfly-shaped stress path observed in the laboratory test. In contrast, the UBCSAND model could approximately capture these behaviors by tracking the stress ratio history to modify the plastic shear modulus.
2. Both models provided reasonable simulations of the excess pore pressure accumulation during cyclic loadings.
3. The relationship between the CRR and the number of uniform loading cycles of the UBCSAND model fit the proposed curves [30] well. The Finn model simulation data deviated from the proposed curves but were still in a reasonable range. Thus, both models were able to adequately model the effects of earthquake magnitude on the CRR.
4. The UBCSAND model reasonably captured the overburden stress effect and the static shear stress effect on the CRR. Given that the dilatant behavior of sand is not included in the formulations of the Finn model, these effects on the CRR were poorly represented by the Finn model.
5. The Finn model can be used for the preliminary numerical simulation of structural damage caused by the strength reduction of the liquefiable soil. In general conditions, the UBCSAND model is highly recommended for numerical simulation to obtain reasonable and reliable results.
6. When the effect of liquefaction hazards or the effectiveness of a mitigation plan need to be evaluated via the numerical analysis, engineers can choose model input parameters according to the (N1)\({}_{60\text{cs}}\) and the simplified liquefaction analysis procedure used in the evaluation of the soil liquefaction occurrence. Then, the numerical analysis can provide reasonable and comparable results.  
[PERSON] developed the conceptualization; [PERSON] and [PERSON] worked on the methodology; [PERSON] and [PERSON] performed the numerical analysis and analyzed the data; [PERSON] prepared the draft manuscript; [PERSON] revised the manuscript. All authors have read and agreed to the published version of the manuscript.  
This research and the APC were funded by the Ministry of Science and Technology, Taiwan R.O.C. under Grant No. MOST 109-2221-E-005-007-MY3.  
**Acknowledgments:** We would like to thank the Ministry of Science and Technology, Taiwan R.O.C., for its support under Grant No. MOST 109-2221-E-005-007-MY3. We also like to thank [PERSON] for valuable suggestions on the numerical simulation.  
**Conflicts of Interest:** The authors declare no conflict of interest.