Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 54 7 2022 09 23 The effect of particle size and degree of saturation on liquefaction potential of sandy soil The effect of particle size and degree of saturation on liquefaction potential of sandy soil 2627 2640 4656 10.22060/ceej.2022.20238.7376 FA Gholam Ali Jafarzadeh Emenabadi Imam Khomeini international university, Qazvin, Iran Seyed Abolhasan Naeini Department of geotechnical engineering, Engineering faculty, Imam khomeini international university, Qazvin, Iran 0000-0001-7711-3087 Reza Ziaie Moayed Professor, Imam Khomeini International University, Engineering Faculty, Iran Journal Article 2021 07 05 In recent years, studies on strength characteristics of unsaturated soils due to the importance of suction in these types of soils have been more focused on cohesive fine-grained soils or compacted sandy soils and limited research on liquefaction of loose unsaturated sandy soils and the effect of particle size on this behavior have been done. In this paper, it has been aimed to investigate the effect of particle size and degree of saturation on liquefaction resistance of loose unsaturated sandy soils by performing a series of cyclic triaxial tests under undrained conditions on three types of sand with different grain size distributions. The results show that variation of pore water pressure and liquefaction resistance in studied sands are largely dependent on particle size and intergranular void ratio, so #131 Firoozkooh sand has the lowest liquefaction resistance in the saturated state due to its higher intergranular void ratio. Also, according to the obtained results, increasing the size of sand grains reduces the matric suction created in the soil mass due to a reduction in the degree of saturation. An increase in the number of cycles to liquefaction and, consequently the liquefaction resistance of the studied sand samples due to a decrease in saturation, especially in sands with finer grains, is another result of this study. In recent years, studies on strength characteristics of unsaturated soils due to the importance of suction in these types of soils have been more focused on cohesive fine-grained soils or compacted sandy soils and limited research on liquefaction of loose unsaturated sandy soils and the effect of particle size on this behavior have been done. In this paper, it has been aimed to investigate the effect of particle size and degree of saturation on liquefaction resistance of loose unsaturated sandy soils by performing a series of cyclic triaxial tests under undrained conditions on three types of sand with different grain size distributions. The results show that variation of pore water pressure and liquefaction resistance in studied sands are largely dependent on particle size and intergranular void ratio, so #131 Firoozkooh sand has the lowest liquefaction resistance in the saturated state due to its higher intergranular void ratio. Also, according to the obtained results, increasing the size of sand grains reduces the matric suction created in the soil mass due to a reduction in the degree of saturation. An increase in the number of cycles to liquefaction and, consequently the liquefaction resistance of the studied sand samples due to a decrease in saturation, especially in sands with finer grains, is another result of this study. https://ceej.aut.ac.ir/article_4656_55563844bcd4bba067fe86ac1f008c7e.pdf