Abstract: Different content of ground granulated blast-furnace slag (GGBS) was used to solidify the muddy clay. The dynamic triaxial test was used to determine the optimal amount of GGBS, and the dynamic strength, dynamic elastic modulus, and dynamic damping ratio of the solidified clay with the optimal amount of GGBS under different confining pressures were analyzed. Finally, SEM test and XRD test were used to analyze the microstructure and composition changes of GGBS solidified clay, and its solidification mechanism was revealed. The results show that when the mixing amount of GGBS is 20% (mass fraction, the same bellow), the dynamic strength of GGBS solidified clay increases stepwise, and 20% is the optimal mixing amount of GGBS. The dynamic strength of 20% GGBS solidified clay is 2 times to 4 times that of the muddy clay, increasing by 45 kPa to 60 kPa, and the maximum dynamic elastic modulus is 3 times to 4 times that of the muddy clay, and the dynamic damping ratio is relatively reduced. Especially under the confining pressure of 100 kPa and 150 kPa, the dynamic damping ratio decreases significantly. The SEM images show that the solidified soil particles with 20% GGBS become agglomerated, the pores between the particles are greatly reduced, and the soil becomes relatively dense. The EDS patterns show that a large amount of Ca²⁺ undergoes ion exchange and granulation, thereby enhancing the binding force between soil particles. The internal friction angle of the clay particles becomes larger, and the strength of the clay body is also improved.

Key words: muddy clay, ground granulated blast-furnace slag, solidification, dynamic characteristic, microscopic mechanism, dynamic triaxial test