Consolidated undrained triaxial testing

Find Labs Significance and Use The shear strength of a saturated soil in triaxial compression depends on the stresses applied, time of consolidation, strain rate, and the stress history experienced by the soil.

Consolidated undrained triaxial testing

In this test method, the shear characteristics are measured under undrained conditions and is applicable to field conditions where soils that have been fully consolidated under one set of stresses are subjected to a change in stress without time for further consolidation to take place undrained conditionand the field stress conditions are similar to those in the test method.

Note 1—If the strength is required for the case where the soil is not consolidated during testing prior to shear, refer to Test Method D or Test Method D Using the pore-water pressure measured during the test, the shear strength determined from this test method can be expressed in terms of effective stress.

This shear strength may be applied to field conditions where full drainage can occur drained conditions or where pore pressures induced by loading can be estimated, and the field stress conditions are similar to those in the test method. The shear strength determined from the test expressed in terms of total stresses undrained conditions or effective stresses drained conditions is commonly used in embankment stability analyses, earth pressure calculations, and foundation design.

Note 2—Notwithstanding the statements on precision and bias contained in this test method. The precision of this test method is dependent on the competence of the personnel performing it and the suitability of the equipment and facilities used.

Agencies which meet the criteria of Practice D are generally considered capable of competent testing. Users of this test method are cautioned that compliance with Practice D does not ensure reliable testing.

Reliable testing depends on several factors; Practice D provides a means of evaluating some of those factors. Specimens are isotropically consolidated and sheared in compression without drainage at a constant rate of axial deformation strain controlled.

Generally, three specimens are tested at different effective consolidation stresses to define a strength envelope. In addition, they are representative of the significant digits that generally should be retained.

The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies or any consideration of end use. It is beyond the scope of this test method to consider significant digits used in analysis methods for engineering design.

Consolidated undrained triaxial testing

The inch-pound units given in parentheses are mathematical conversions which are provided for information purposes only and are not considered standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this test method.

In this system, the pound lbf represents a unit of force weightwhile the unit for mass is slugs. This implicitly combines two separate systems of units; that is, the absolute system and the gravitational system.

It is scientifically undesirable to combine the use of two separate sets of inch-pound units within a single standard. Density is mass per unit volume whereas unit weight is force per unit volume.

In this standard density is given only in SI units. After the density has been determined, the unit weight is calculated in SI or inch-pound units, or both. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.The shear strength of a saturated soil in triaxial compression depends on the stresses applied, time of consolidation, strain rate, and the stress history experienced by the soil.

In this test method, the shear characteristics are measured under undrained conditions and is applicable to field. The Consolidated-Undrained Test is typically used when testing the long and short-term strength of cohesive soils.

What is the Consolidated-Drained Test? In the Consolidated-Drained test, the soil is allowed to consolidate before testing, using the same procedure as described above. A consolidated undrained triaxial test was carried out by 16 separate groups to give a broad appreciation of soil behaviour by plotting the resulting effective stress paths - Consolidated Undrained Triaxial Testing Essay introduction.

Results. A drained consolidation test was first conducted to determine the appropriate strain rate for consolidated-undrained (CU) triaxial testing. Opalinus Clay samples were then consolidated in the triaxial rig to mean effective stresses in the range from 3 to 52 MPa and eventually sheared.

Consolidated Undrained Triaxial Compression Test for Cohesive Soils1 consolidated during testing prior to shear, refer to Test Method D or Test Method D Using the pore-water pressure measured during the test, the shear strength determined from this test method can be.

A comprehensive set of experimental data on Bangkok subsoils from oedometer and triaxial tests are analysed in this paper in order to determine the stiffness and .

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