: These rules describe how the yield surface evolves as the material deforms.
: The yield surface shifts its position in stress space, often used to model the Bauschinger effect in cyclic loading. fundamentals of plasticity in geomechanics pdf
: Assumes the plastic strain increment is normal to the yield surface (Normality Rule), common in metal plasticity but often less accurate for frictional materials like soil. : These rules describe how the yield surface
: This describes the direction and relative magnitude of plastic strain increments once yielding occurs. : This describes the direction and relative magnitude
: Traditionally used for metals but adapted for certain cohesive soils like undrained clay.
Plasticity theory replaces real, particulate materials (like sand or clay) with an idealised continuum that behaves elastically until a specific stress limit is reached. Key elements of this theory include:
: A decrease in strength after peak stress, common in over-consolidated clays and brittle rocks. Advanced Constitutive Models