Abstract: Generally, synthetic fiber, mineral fiber and plant fiber are added into soil to enhance the strength and deformation resistance of soil. The unconfined compressive test and splitting tensile test of three fiber-lime-soils under freeze-thaw cycle were carried out to study the variation of compressive and tensile properties of soil with freeze-thaw times. The test results showed that the optimum fiber rates of polypropylene fiber-lime-soil, basalt fiber-lime-soil and palm fiber-lime-soil were 0.2%, 0.2%, and 0.4% respectively, whether under freeze-thaw cycle or not. With the increase of freeze-thaw times, the compressive strength and tensile strength of the three fiber-lime-soils demonstrated phased downward trend, and the failure strains of fiber-lime-soil were greater than that of lime-soil. Under freeze-thaw cycle, the compressive strength, tensile strength, and deformation resistance of polypropylene fiber-lime-soil were better than those of basalt fiber-lime-soil and palm fiber-lime-soil. The interface force and the spatial constraint between fibers and soil particles enhanced the freeze-thaw durability of soil. By comparing and analyzing the test results of three types of fiber-lime-soil, it was found that the freeze-thaw resistance of polypropylene fiber-lime-soil was the optimum.

Key words: fiber reinforced soil, fiber rate, freeze-thaw cycle, compressive strength, tensile strength