15-10-2010, 11:27 AM
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The Mechanics of Biosolids
Kevin Tang
Professor Ian Collins, Dr. Tam Larkin
Department of Engineering Science
The University of Auckland
Biosolids is another term for ‘treated sludge’.
Instead of landfill, if biosolids are suitable to be used in embankment, rehabilitation of soil, quarries, Football fields etc.
Project Description
Determining a simple model for the mechanics of biosolids, using viscoplastic constitutive equations.
The soil Soil model.
Key notes:
Compressible, soft soil
Viscoplastic: rate dependent deformations/yielding.
Biosolids with a low permeability.
Cohesionless (in a drained test), non-zero cohesion in an undrained triaxial test.
Assumptions
Due to flattening nature of sample in a triaxial compression test. The material is regarded to yield at a maximum strain of 20%.
Solid is isotropic. Fibrous matter has negligible impact on direction material is loaded.
Assume a constant coefficient of consolidation.
Experiment tests
Triaxial test – laboratory test that records the stress response to straining while it identifies shear strength, cohesion, phi angle.
Triaxial test models the shear-stress strain relationship of sample in compression.
The sample size are 150mm in height and 75mm in diameter.
Consolidation test: Volumetric strain from identifies the S, viscoplastic modulus.