Abstract: The mechanical property of tailing sand in tailings dam were studied through the consolidated drained triaxial (CD) tests and compression tests.The strength characteristics and stress-strain curve of tailing sand under different compaction degree were discussed.The results showed that，with the relative density of tailing sand increased (from 0.47 to 0.73)，its strength index (cohesion and friction angle) were increased.The compression tests indicated that for tailing sand with the same porosity ratio，its compression factor was reduced，the compression modulus increased，but the compression index remained almost unchanged with the vertical pressure increasing (from 100 kPa to 400 kPa).With the porosity ratio increasing，the compression factor and compression index of tailing sand increased，and the compression modulus decreased.Thus，its compressive strength also increases.Therefore，in the actual project，an increase of tailing sand density can improve the strength and the stability of the tailings dam.

Key words: Tailing sand, Consolidated drained triaxial (CD) test, Compression test, Shear strength