To investigate the shear strength and microstructure of undisturbed loess polluted by landfill leachate, a series of laboratory tests were carried out to determine the shear strength, mineral composition, surface morphology, particle size distribution and pore characteristics of the loess. The stress-strain curve of undisturbed soil polluted by landfill leachate showed typical strain-softening behavior. The deviatoric stress, cohesion and angle of shearing resistance of undisturbed soil decreased at increased landfill leachate concentrations, d...