Deformation constitutive model of subgrade soil under intermittent cyclic loading

Area of Science:

• Geotechnical Engineering
• Soil Mechanics
• Continuum Mechanics

Background:

• Subgrade soils in infrastructure like subways and railways experience intermittent cyclic loads.
• Understanding soil deformation under these conditions is crucial for structural integrity.

Purpose of the Study:

• To develop a novel constitutive model for subgrade soil deformation under intermittent cyclic loading.
• To analyze the model's effectiveness and applicability compared to existing models.

Main Methods:

• Established a fractional generalized Kelvin model by replacing the Newtonian dashpot with a fractional Abel dashpot.
• Proposed a nonlinear viscoplastic body model with damage, connected in series with the fractional Kelvin model.
• Analyzed the model's performance against experimental data and other constitutive models.

Main Results:

• The developed model accurately reflects the influence of confining pressure, frequency, and dynamic stress amplitude on cumulative plastic strain.
• The model successfully characterizes three types of cumulative plastic strain development: stable, critical, and failure.
• Fitting parameters demonstrated rational trends with increasing loading stages, validating the model's accuracy.

Conclusions:

• The proposed constitutive model provides a robust framework for predicting subgrade soil behavior under intermittent cyclic loading.
• The model's ability to capture complex deformation patterns enhances its applicability in geotechnical engineering.
• The findings contribute to improved design and safety assessments for transportation infrastructure.