China
Africa
Explore chapters and articles related to this topic
Compaction
Published in Bernardo Caicedo, Geotechnics of Roads: Fundamentals, 2018
Mechanical tests available in soil mechanics impose different kinds of stresses and strains. However, the stress paths that are available and accessible in laboratory tests have technological limits. There are two kinds of stress-strain paths for laboratory testing: Stress strain paths with a fixed orientation of the principal axes of stress and strains include Oedometric tests.Isotropic compression tests.Triaxial compression tests.Triaxial extension tests.Stress paths with changes in the directions of stress and strain: Compression Extension triaxial test.Simple shear test.Hollow cylinder test.Gyratory compaction test.
Stress state and noncoaxiality of Leighton Buzzard sand in NGI-type bi-directional simple shear tests
Published in Marine Georesources & Geotechnology, 2021
In geotechnical engineering, several laboratory tests are widely used to study the shear behavior of soils, such as direct shear test, triaxial test, hollow cylinder test, and direct simple shear test. Among available testing apparatuses, a newly developed apparatus, bi-directional NGI-type simple shear apparatus, it is possible to apply shear stresses in two perpendicular directions, while other devices can only apply one shear stress on a soil sample due to the limitation of these apparatuses. In most developed bi-directional simple shear apparatus, a stack of rings is used for lateral constraints of tested samples (Boulanger et al. 1993; Casagrande and Rendon 1978; DeGroot, Germaine, and Ladd 1993; Ishihara and Yamazaki 1980; 1975; Rutherford 2012), which is a unique characteristic as an NGI-type simple shear apparatus. However, due to the unique constraints, sample’s lateral stress is difficult to be measured. As a result, the complete stress state is unknown which limited its interpretation of results.