دانلود رایگان مقاله انگلیسی ارزیابی پتانسیل روانگرایی خاک با استفاده از رویکرد انرژی - اشپرینگر 2017

Abstract

Liquefaction has caused many catastrophes during earthquakes in the past . The strain energy-based method is one of the modern methods used to estimate liquefaction potential. In this study, wide-ranging experimental data were gathered from cyclic tests and centrifuge modeling of liquefaction. A model was then developed based on the strain energy needed for liquefaction to occur using the group method of data handling and the gravitational search algorithm. Contributions of the effective variables were evaluated through a sensitivity analysis. To check the accuracy of the developed strain energy model, cyclic triaxial tests were conducted on sandy soil and silty sand specimens. Comparison of the energy required to initiate liquefaction in the tested soil specimens with values predicted by the developed model indicated high accuracy of the energy-based model. Subsequently, the accuracy of the energy model was assessed in field conditions using the amount of strain energy released by real earthquakes in various sites. The ability of the model to distinguish liquefied areas from non-liquefied ones confirms its accuracy in field conditions. Finally, the developed model was compared with some available relationships to estimate the strain energy required for liquefaction to occur.

Summary and conclusions

A wide-ranging database of cyclic experiments on sandy soils and silty sands was gathered in this study. Most important parameters affecting strain energy (W) required for liquefaction occurrence were determined through literature review and by studying soil behavior in different conditions. A model was developed using NF-GMDH and GSA to estimate W. Assessing the accuracy of developed model indicates high accuracy of the NF-GMDH-GSA-based model in estimation of the strain energy (R2 = 0.924, MAE = 0.027, RMSE = 0.039). Comparison of strain energy results from centrifuge tests with predicted values confirmed reasonable accuracy of the developed model. The sensitivity analysis was performed to investigate the effect of each parameter on the amount of W and to ensure the behavior of the developed model. The W increased by increasing σ’0, Dr, and D50. In addition, W decreased by increasing Cu. An increase in FC first increased and then decreased W. Generally, the changes in W when subjected to the most important parameters affecting W were consistent with experimental tests results.