What is undrained triaxial test?
The standard consolidated undrained test is compression test, in which the soil specimen is first consolidated under all round pressure in the triaxial cell before failure is brought about by increasing the major principal stress.
What are undrained consolidated undrained and drained test?
In a ‘consolidated undrained’ test the sample is not allowed to drain. The shear characteristics are measured under undrained conditions and the sample is assumed to be fully saturated. Measuring the pore pressures in the sample (sometimes called CUpp) allows approximating the consolidated-drained strength.
What are the types of triaxial test?
There are 3 main types of triaxial tests:
- Unconsolidated – undrained (UU)
- Consolidated – undrained (CU)
- Consolidated – drained (CD)
What is unconsolidated undrained test?
A triaxial unconsolidated undrained compression test is used to determine the mechanical properties of soil by subjecting the soil sample to varying levels of stress and drainage conditions. The test is generally carried out on three specimens os the same soil sample but subjected to different confining stresses.
What is consolidated undrained triaxial compressive strength?
A triaxial consolidated undrained compression test is carried out to determine the shear strength of the soil. The pores pressure of the soil is measured and the soil is consolidated under pressure from all around in a triaxial cell before failure is induced by increasing the major principal stress.
Where are unconsolidated undrained tests used?
A triaxial unconsolidated undrained compression test is used to determine the mechanical properties of soil by subjecting the soil sample to varying levels of stress and drainage conditions. The saturated specimen is subjected to confining fluid pressure in a triaxial cell.
What do you mean by undrained cohesion?
Cohesion is a function of depth, where depth is measured from the top of the material layer that is local to the slice, to the center of a slice base. Cu (Top) is the undrained Cohesion at the top of the material layer (local to the slice). Cu Change is the rate of change of undrained Cohesion with depth.
What is unconsolidated undrained?
The soil is set to be in unconsolidated state, only when the volume of soil remains the same without the air replacement. This soil is loose in the natural state. In case of undrained conditions, the pore water is not allowed to drain out of soil.
What is cu uu test?
In a CU (undrained) test, pore pressure changes (U) are allowed to take place and are measured. In a CD (Drained) test drainage is allowed to prevent pore pressure changes happening. In this type of test the volume change of the sample is measured during the shear stage.
What is the difference between drained and undrained soil?
As you all know in drained condition, the pore water can easily drain out from the soil matrix while in undrained condition the pore water is unable to drain out or the rate of loading is much quicker than the rate at which the pore water is able to drain out.
What can a VNG diagnose?
Doctors use a VNG test to diagnose vestibular disease. In lay terms, a vestibular disease is an inner-ear disease. The test measures whether an inner-ear condition may be causing you to feel dizzy, unbalanced, unsteady or nauseated.
What is consolidated drained triaxial test?
Consolidated Drained (CD) Test: The consolidated drained triaxial compression test , with volume change measurement during shear is carried out in a similar sequence to the consolidated undrained test, but during shear the back pressure remains connected to the specimen which is loaded sufficiently slowly to avoid the development of excess pore pressures.
What are the different types of triaxial tests?
Types of triaxial tests Consolidated drained (CD) In a ‘ consolidated drained’ test the sample is consolidated and sheared in compression slowly to allow pore pressures built up by the shearing to dissipate. Consolidated undrained (CU) In a ‘consolidated undrained’ test the sample is not allowed to drain. Unconsolidated undrained. True triaxial test.
What is a triaxial test?
Triaxial testing is a method used to determine the stress-strain properties of soils by subjecting soil samples to constant lateral pressure while increasing vertical pressure. This test measures stresses in three mutually perpendicular directions.