Abstract: Uniaxial compression strength of full tailings-cemented filling body based on four gray sand ratio and five concentration of slurry were tested so as to obtain its physical and mechanical properties under uniaxial compression.Then,triaxial compression experiments under four different confining pressure were tested based on gray sand ratio of 1∶6,1∶8 and concentration of slurry of 65%,70% to obtain stress-strain curve and physical and mechanical parameters of filling body.According to the experimental results,the constitutive model of linear elastic-elastic-plastic-plastic softening-ideal plastic was established,which divided the stage of post-peak strain softening of filling body into two cases：When the confining pressure is less,strain softening and brittle stress drop is showed obviously；When the confining pressure is higher,the stress- strain curve shows that strain softening is not obvious,which directly comes into the plastic flow after the peak,and the difference between residual strength and peak intensity decreases.This result provides a basis for strength design of filling body.

Key words: Full tailings-cemented filling body, Triaxial compression, Stress-strain curve, Elastoplastic constitutive model