冻融作用下三类纤维加筋固化土的抗压抗拉性能

合成纤维、矿物纤维和植物纤维加筋土，增强了土的强度和抗变形性能。开展冻融作用下的无侧限抗压试验和劈裂抗拉试验，研究聚丙烯纤维、玄武岩纤维和棕榈纤维加筋石灰固化土的抗压和抗拉性能随冻融次数的变化规律。结果表明：未冻融和冻融环境下，聚丙烯纤维加筋固化土、玄武岩纤维加筋固化土和棕榈纤维加筋固化土的最优质量加筋率分别为0.2%、0.2%和0.4%。随冻融次数增加，三类纤维加筋固化土的抗压强度和抗拉强度均呈阶段性下降，纤维加筋固化土的破坏应变均大于石灰固化土。冻融作用下，聚丙烯纤维加筋固化土的抗压强度、抗拉强度和抗变形性能均优于另两类加筋固化土。纤维与土颗粒间的界面作用力和纤维对土的空间约束作用，增强了土的冻融耐久性。对比三类纤维加筋固化土的试验结果，聚丙烯纤维加筋固化土的抗冻融性能最优。

Compressive and tensile properties of three fiber-lime-soils under freeze-thaw cycle

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.