Comparison of classic particle swarm optimization with statistical adaptive dynamic particle swarm optimization results.

Comparison of classic particle swarm optimization with statistical adaptive dynamic particle swarm optimization results.</p

Settlement-time curve of the center of the subgrade surface.

Settlement-time curve of the center of the subgrade surface.</p

Model parameters of Shanghai soft clay [38].

Model parameters of Shanghai soft clay [38].</p

Instantaneous yield surface.

Instantaneous yield surface.</p

Vertical displacement on the 592^nd day.

Vertical displacement on the 592nd day.</p

Parts of back analytical parameters of the fractional differential constitutive model.

Parts of back analytical parameters of the fractional differential constitutive model.</p

Parts of the experimental parameters of the fractional differential constitutive model.

Parts of the experimental parameters of the fractional differential constitutive model.</p

Details of test groups used in this study.

Details of test groups used in this study.</p

Developed fractional differential constitutive model of soft clay.

Developed fractional differential constitutive model of soft clay.</p

Comparison curve between the fractional differential constitutive model and undrained triaxial creep test (Condition 1, confining stress: 100 kPa, stress difference ratio: 0.25; Condition 2, confining stress: 100 kPa, stress difference ratio: 0.50; Condition 3, confining stress: 200 kPa, stress difference ratio: 0.50).

Comparison curve between the fractional differential constitutive model and undrained triaxial creep test (Condition 1, confining stress: 100 kPa, stress difference ratio: 0.25; Condition 2, confining stress: 100 kPa, stress difference ratio: 0.50; Condition 3, confining stress: 200 kPa, stress difference ratio: 0.50).</p