Tensile strength of fiber reinforced soil under freeze-thaw condition

Fiber reinforced soil technique has attracted the attention of numerous researchers. However, very limited information has been reported on its tensile behavior. Furthermore, the effect of fiber reinforcement on soil tensile property under freeze-thaw condition almost has not been investigated. To evaluate the factors influencing the tensile strength characteristics of fiber reinforced soil subjected to freeze-thaw cycles, direct tensile tests were performed using an 8-shaped compaction mold. To resolve the distributed randomness of fibers along the tensile failure plane in parallel specimens, the fibers were artificially and directionally arranged in the main tensile region of specimens. The experimental results indicate: (1) The addition of fibers to soil originates an increase in the stiffness, peak strength and residual strength, and a change in failure behavior from brittle to more ductile after 1st freeze-thaw cycle; (2) The tensile strength of reinforced soil subjected to freeze-thaw cycles significantly increases with the increasing of soil dry density and fiber content until optimum content; (3) With the increasing of water ratio, the tensile strength of fiber reinforced soil increases under the optimum water ratio and then decreases above it. The characteristic of tensile strength versus water ratio presents a typical unimodal pattern; (4) By increasing the number of freeze-thaw cycles to 9, the tensile strength decreases. Most of the strength reduction occurs at the first 5 freeze-thaw cycles, and the strength remains relatively constant for the 6th-9th cycles.