Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 4 2021 06 22 Investigation of loading rate effect on the shear strength of clay-sand mixture in triaxial test Investigation of loading rate effect on the shear strength of clay-sand mixture in triaxial test 1591 1606 3665 10.22060/ceej.2019.16947.6439 FA Javad Ghaffari Department of Civil Engineering, Marand Technical College, University of Tabriz, Tabriz,Iran Reza Binay Master of Geotechnical Engineering, Islamic Azad University, Marand Branch, Marand, Iran Journal Article 2019 09 13 <span style="letter-spacing: .05pt;">The strength behavior of soil is affected by strength parameters including soil cohesion and its internal friction angle. These parameters are influenced by factors such as soil density, soil type, loading rate, moisture content, confining pressure and Etc. In this paper, the effect of loading rate on the shear strength behavior of clay-sand mixtures is investigated using the triaxial test. In this research, 8 types of "clay:sand" composite materials with weight ratios of 100:0, 80:20, 60:40, 40:60, 30:70, 20:80, 10:90 and 0:100 were used. To investigate the effect of loading rate, samples were subjected to non-uniform loading rates of 0.1, 1, and 5 mm/min with a defined load pattern. In this study, three confining pressures of 100, 300, and 500 kPa were used. The results of this study show that, depending on the amount of confining pressure, the sudden change in loading rate has different effects on the strength of samples with different percentages of clay-sand combination. Deviator stress variations, as well as the slope of the stress-strain curve, depending on the amount of sand at the moment of a sudden change in loading rate. In other words, changes in deviator stress and slope of the stress-strain curve are directly related to the amount of sand from one limit to the next. This limit of sand is 40% for low confining pressure (100 kPa) and 20% for higher confining pressure (300 and 500 kPa).</span> <span style="letter-spacing: .05pt;">The strength behavior of soil is affected by strength parameters including soil cohesion and its internal friction angle. These parameters are influenced by factors such as soil density, soil type, loading rate, moisture content, confining pressure and Etc. In this paper, the effect of loading rate on the shear strength behavior of clay-sand mixtures is investigated using the triaxial test. In this research, 8 types of "clay:sand" composite materials with weight ratios of 100:0, 80:20, 60:40, 40:60, 30:70, 20:80, 10:90 and 0:100 were used. To investigate the effect of loading rate, samples were subjected to non-uniform loading rates of 0.1, 1, and 5 mm/min with a defined load pattern. In this study, three confining pressures of 100, 300, and 500 kPa were used. The results of this study show that, depending on the amount of confining pressure, the sudden change in loading rate has different effects on the strength of samples with different percentages of clay-sand combination. Deviator stress variations, as well as the slope of the stress-strain curve, depending on the amount of sand at the moment of a sudden change in loading rate. In other words, changes in deviator stress and slope of the stress-strain curve are directly related to the amount of sand from one limit to the next. This limit of sand is 40% for low confining pressure (100 kPa) and 20% for higher confining pressure (300 and 500 kPa).</span> https://ceej.aut.ac.ir/article_3665_6915849303a3fe93657587cb9c469f00.pdf