Triaxial Shear Characteristics of Biological Gum-fiber-reinforced Loess
This study aims to investigate the shear strength characteristics of biological gum-fiber-reinforced soil slope protection material under three-dimensional stress.Guar gum(GG)is used as the binding reinforcement material,and polypropylene fiber(PF)is used as the toughening reinforcement material.A series of triaxial compression tests were performed on loess under controlled biological gum-fiber ratio conditions.The characteristics of the stress-strain curves,variations in shear strength parameters,and main failure modes were analyzed.Additionally,the cooperative reinforcement mechanism for GG and PF in loess was discussed.The results show that GG can effectively increase the deviatoric stress value under a small strain and that PF can significantly change the shape of the stress-strain curve.When both are added to the loess,the stress-strain curves under different confining pressures exhibit persistent hardening behavior,good failure toughness,and high deviating stress values,and are not affected by strain.A mixture of GG and PF is beneficial for improving the shear strength of soil.With an increase in the GG or PF content,the shear strength initially increases and then decreases or increases gradually.When the GG and PF contents are 1.0％and 0.5％,respectively,the shear strength of the reinforced loess is optimized.Compared with plain loess,the cohesion increases by 230.6％and the internal friction angle increases by 24.8％.The combination of GG-PF effectively inhibit the lateral deformation of the soil,and the damage pattern of samples with an optimum biological gum-fiber ratio show slight swelling damage.The triaxial shear strength characteristics of the soil are comprehensively improved by the hydrogel action of GG,reinforcing effect of PF,and their mutual promotion effect.These results provide an important theoretical basis for the selection of design parameters in subgrade slope protection engineering.
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