Abstract: The existing hollow cylindrical sample preparation technology has been improved to solve the problems of large disturbance and cumbersome steps in the original sample preparation method. The hollow torsion shear apparatus is used as the test equipment, with different frequencies and different dynamic stress amplitudes. For the influencing factors, the influence on the axial cumulative strain and softening index of Zijingang soft clay is analyzed. Under the rotation of the principal stress axis, there is an obvious critical cyclic stress value for coastal structural soft soils. When the frequency changes within the range of 0.1 Hz to 1 Hz, the number of cycles required for the hollow cylindrical specimen to reach the failure state under the action of the 0.1 Hz cyclic load. At the same time, frequency and cyclic stress ratio have a significant influence on the softening characteristics of coastal structural soft soils, and the effects of frequency and dynamic stress ratio on the axial cumulative strain and softening index are mutually coupled and mutually influencing, not alone exist.

Key words: Coastal Structural Soft Soils, Softening Characteristics, Structural Property, Axial Cumulative Strain, Hollow Cylindrical Specimen, Softening Index