Triaxial testing will yield static strength properties of the material while ultrasonic measurements will give dynamic strength properties. The two can be related to each other by using various relationships between Young's Modulus, Bulk Modulus, Shear Modulus and Poisson's ratio. Static results should be lower than the dynamic results.
Strictly speaking, in 2D it is a yield line, not a surface (you would have to do a £D plot for that). In order to construct a deviatoric yield surface plot you require the triaxial data for a sample for at least three differing confining pressures. You will then essentially be creating a series of mohr circle plots (shear stress vs Sigma1 - Sigma3) of the deviatoric stress circles at the failure stress of the samples. A straight line is then drawn that touches the upper bounds of the three circles without passing through them. This line is the 2D deviatoric yield plot. There is free software available that will do this for you. Please see the related links.
In a consolidated drained test the sample is consolidated and sheared in compression with drainage. The rate of axial deformation is kept constant, i.e. is strain controlled. The idea is that the test allows the sample and the pore pressures to fully consolidate (i.e. adjust) to the surrounding stresses. The test may take a long time to allow the sample to adjust, in particular low permeability samples need a long time to drain and adjust strain to stress level
Normal stress and shear stress
A factor of safety against yield is applied to design stress Yield Stress/ Design Stress = Factor of safety The factor of safety varies for different industries; 1.5 is used in structural steel design for buildings; 1.25 or even 1.1 for aircraft/space systems
Shear box tests are generally suitable for cohensionless soil except fine sand and silt whereas triaxial test is suitable for all types of soils. Pressure changes and volume changes can be measured directly in triaxial test which is not possible in shear box test. Pore water pressure can be measured in the case of triaxial test which is not possible in direct shear test. Triaxial machine is more adaptable. The stress distribution across the soil sample in the failure plane is more uniform in triaxial test. The complete state of stress is known at all intermediate stages up to failure during the triaxial test whereas only the stress at failure are known in the direct shear test. In triaxial test, there is complete control over the drainage conditions, where control of drainage conditions is very difficult in shear box test.
Ball-and-socket joint is an example of triaxial (or multiaxial) joint.
T. Balkir has written: 'Triaxial tests on soils'
G. J. Watts has written: 'Three-dimensional model for metal flow under triaxial strain conditions'
Triaxial testing will yield static strength properties of the material while ultrasonic measurements will give dynamic strength properties. The two can be related to each other by using various relationships between Young's Modulus, Bulk Modulus, Shear Modulus and Poisson's ratio. Static results should be lower than the dynamic results.
Strictly speaking, in 2D it is a yield line, not a surface (you would have to do a £D plot for that). In order to construct a deviatoric yield surface plot you require the triaxial data for a sample for at least three differing confining pressures. You will then essentially be creating a series of mohr circle plots (shear stress vs Sigma1 - Sigma3) of the deviatoric stress circles at the failure stress of the samples. A straight line is then drawn that touches the upper bounds of the three circles without passing through them. This line is the 2D deviatoric yield plot. There is free software available that will do this for you. Please see the related links.
good stress, medium stress and bad stress
you stress
aVF's negative reference point is formed by finding the midway point between the right arm and left arm. (triaxial diagram)
Positive stress
mental stress
Positive stress