Triaxial Tests to Characterize the Shear Strength Behavior of Mechanical Biological Treatment Waste in Hangzhou, China

Abstract

Mechanical biological treatment (MBT) waste from the Tianziling landfill in Hangzhou, China, was collected for composition analysis, sample preparation, and conduction of triaxial unconsolidated-undrained and consolidated-undrained tests in an environmental geotechnical laboratory. The principal findings were as follows. (1) The component analysis indicated that the MBT waste comprised plastics, textiles, glass, lime soil, unidentified materials, and so on. (2) The triaxial compression test results showed that the deviatoric stress gradually increased with an increasing axial strain. The relationship between the deviatoric stress and axial strain took the form of a strain hardening curve. (3) The stress–strain relationship of the MBT waste conforms to the Duncan–Chang model. The ranges of the model parameters a and b were obtained. A power function relationship between the model parameters a and b and the confining pressure was established. (4) The values of the cohesion, internal friction angle, effective cohesion, and effective internal friction angle of the shear strength parameters were obtained. The cohesion c was 28.6 kPa, the internal friction angle φ was 23.3°, the effective cohesion c′ was 33.5 kPa, and the effective internal friction angle φ′ was 32.2°. These results can provide a theoretical basis for the stability analysis of MBT landfills.