Abstract: Graded loading and unloading test was conducted with different frequencies by using GDS dynamic triaxial instrument to explore the influences of sea sand content and vibration frequency on the dynamic stress-dynamic strain (σ_d-ε_d) relationship, dynamic elastic modulus and damping ratio of sea sand composite solidified silt. Test results show that the σ_d-ε_d curve is linear at small dynamic stress; when dynamic stress is increased stepwise, dynamic strain increases rapidly until failure. At a given frequency, the stress-strain curve first rises and then moves down with the increase of sea sand content; the stress-strain curve of solidified silt with 15% dosage of sea sand is at the top. At a given sea sand content, the dynamic deformation under high frequency is smaller than that at low frequency, and the dynamic strength is higher than that at low frequency. Under varying sea sand content and frequency and growing dynamic stress, the dynamic elastic modulus E_d of solidified silt first increases and then declines, the damping ratio λ decreases slightly and then gradually increases, and the hysteretic energy consumption ΔW increases nonlinearly. The corresponding ΔW under the same dynamic stress decreases with the increase of frequency. By increasing the frequency and mixing a proper amount of sea sand, the dynamic elastic modulus of solidified silt can be improved, and the damping ratio of the solidified silt can be effectively reduced.

Key words: sea sand composite solidified silt, GDS dynamic triaxial test, dynamic stress-strain curve, dynamic elastic modulus, damping ratio, hysteretic energy consumption