Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 54 2 2022 04 21 Comparison of Dynamic Behavior of Reconstituted and Core Barrel Sandy Soil Sample by Resonant Column Test in Flexural Mode Comparison of Dynamic Behavior of Reconstituted and Core Barrel Sandy Soil Sample by Resonant Column Test in Flexural Mode 521 540 4405 10.22060/ceej.2021.18979.7016 FA Ata Aghaei Araei Associate professor, Geotechnical Engineering Department, Road, Housing & Urban Development Research Center, Tehran, Iran Somayeh Ahmadi Civil Engineering Faculty, Yazd Univercity, Yazd, Iran Hamid Mehrnahad 2- Associate professor, University of Yazd, Yazd, Iran Nahid Attarchian Assistant professor, Geotechnical Engineering Department, Road, Housing & Urban Development Research Center, Tehran, Iran Journal Article 2020 09 09 Determining the dynamic properties of soils is an important issue in solving seismic geotechnical engineering problems. In this respect, several types of field and laboratory methods are available with different advantages and limitations regarding solving different problems. The difference between the results of in-site and laboratory tests is one of the engineers’ difficulties. Some reasons for the difference between the values ​​of dynamic parameters which achieved from field and laboratory tests, are the remolding effect of samples, difference in stress conditions and loss of cementation; negligence of these facts in soil dynamic properties may lead to serious damage due to unrealistic soil analysis. Among the laboratory methods, the resonant column test is one of the methods which determines the dynamic properties of soils at small strains. In this research, Young’s modulus and damping ratio of core barrel and reconstituted earth materials have been studied by performing resonant column test in flexural mode. The effects of confining pressure and anisotropic confining pressure was studied by using the Young’s modulus and damping ratio versus flexural strain diagrams. The results of the study indicate that reconstituting reduces the Young’s modulus, but the variation of damping ratio versus shear strain for core barrel and reconstituted samples is negligible. Increase in the confining pressure and anisotropic confining pressure result in the increase of Young’s modulus. Comparing the damping ratio results with the two methods of free vibration decay and half-power bandwidth indicates that the damping ratio values ​​obtained from the half-power bandwidth method are higher. Determining the dynamic properties of soils is an important issue in solving seismic geotechnical engineering problems. In this respect, several types of field and laboratory methods are available with different advantages and limitations regarding solving different problems. The difference between the results of in-site and laboratory tests is one of the engineers’ difficulties. Some reasons for the difference between the values ​​of dynamic parameters which achieved from field and laboratory tests, are the remolding effect of samples, difference in stress conditions and loss of cementation; negligence of these facts in soil dynamic properties may lead to serious damage due to unrealistic soil analysis. Among the laboratory methods, the resonant column test is one of the methods which determines the dynamic properties of soils at small strains. In this research, Young’s modulus and damping ratio of core barrel and reconstituted earth materials have been studied by performing resonant column test in flexural mode. The effects of confining pressure and anisotropic confining pressure was studied by using the Young’s modulus and damping ratio versus flexural strain diagrams. The results of the study indicate that reconstituting reduces the Young’s modulus, but the variation of damping ratio versus shear strain for core barrel and reconstituted samples is negligible. Increase in the confining pressure and anisotropic confining pressure result in the increase of Young’s modulus. Comparing the damping ratio results with the two methods of free vibration decay and half-power bandwidth indicates that the damping ratio values ​​obtained from the half-power bandwidth method are higher. https://ceej.aut.ac.ir/article_4405_bd470ca955d9497bbcb808e59952fffc.pdf