Study on the mechanical properties of flax fiber-reinforced silty clay contaminated by zinc-ion solution

Mechanical properties of fiber-reinforced soil after soaking in heavy metal ion solution have great influences on safety and stability of the reinforcement, herein the mechanical properties of optimum moisture content of different concentrations of zinc ions contaminated soil were studied through shear test, compression test and triaxial test. The compressive modulus, compression coefficient and porosity ratio of different concentrations of the zinc-ion contaminated soil under different pressure were studied, and the variation characteristics of internal friction angle and cohesion were also investigated, thereafter, the causes of the change of cohesion and internal friction angle were analyzed from the microscopic perspective. The results show that the shear strength of contaminated reinforced soil increases with the increase of confining pressure at the same zinc ions concentration. And at the same confining pressure, with the increase of zinc ions concentration, the shear strength of contaminated reinforced soil first increases and then decreases. With the increase of zinc ions concentration, the internal friction angle and compression coefficient increase, the cohesion and the modulus of compression decrease. With the increase of normal stress, the compression coefficient decreases firstly and then increases, and the compression modulus increases and then decreases. With the concentration of zinc ions increases at lower normal stress, the amount of shrinkage increases and the compression coefficient decreases. While at higher normal stress, the compressive modulus decreases and the compression coefficient increases.