Experimental Study on the Mechanical Properties of Cotton Straw Fiber-Reinforced Soil Interface under Dry-Wet Cycles

Abstract

Fiber-reinforced soil technology has been employed in engineering. However, reinforced soil often undergoes dry-wet (D-W) changes because of high temperatures and rain in summer; consequently, its strength deteriorates. Its mechanical properties are mainly affected by the force between a fiber interface and a soil matrix. In this study, the effect of D- W cycles on the interfacial mechanical properties of cotton straw fiber-reinforced soil was investigated. Fiber-reinforced soil with different normal stresses was subjected to single fiber pullout tests on the 0th, 1st, 3rd, 6th, and 9th D-W cycles. Results showed that the trend of the changes in the pullout force-displacement curve was consistent; in particular, the trend initially showed a linear increase. Then, it peaked, decreased, and finally stabilized. The pullout force had a linear relationship with normal stress and increased linearly as normal stress increased. The relationship between interfacial shear strength and the number of D-W cycles exponentially decreased, and the most significant decrease occurred in the first to three D-W cycles.