Table of Contents
What does a triaxial test measure?
The triaxial test enables parameters such as cohesion (c’), internal angle of friction (φ’) and shear strength to be determined. The triaxial test can also be used to determine other variables such as stiffness and permeability with the correct equipment.
What is the purpose of triaxial shear test?
A triaxial shear test is a common method to measure the mechanical properties of many deformable solids, especially soil (e.g., sand, clay) and rock, and other granular materials or powders. There are several variations on the test.
How do you do a triaxial test?
A de-aired, coarse porous disc or stone is placed on the top of the pedestal in the triaxial test apparatus. A filter paper disc is kept over the porous stone. The specimen of the cohesive soil is then placed over the filter paper disc. The usual size of the specimen is about 37.5mm diameter and 75.0mm height.
What are the merits of triaxial test?
Advantages of Triaxial Test
- The stress distribution on the failure plane is uniform.
- The specimen is free to fail on the weakest plane.
- There is complete control over the drainage.
- Pore pressure changes and the volumetric changes can be measured directly.
What is B value in triaxial test?
The B-value, measured after setting up a specimen for triaxial testing, is used for evaluating the degree of saturation of a specimen. However, the stress conditions used when measuring the B-value have not been standardized.
What is undrained shear strength of clay?
The undrained shear strength (su) is defined as one-half of the peak value of (P1 – P3). For CU tests, the slower strain rates of Raymond should be retained to more closely approximate field rates of loading. The UU test provides a measure of Su at the in situ water content of the sample.
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 are the limitations of triaxial test?
Disadvantages of Triaxial Test The drained test takes place a longer period in comparison with a direct shear test. It is not possible to determine the cross sectional area of the specimen at larger strains, as the assumption that the specimen remains cylindrical does not hold good.
What is a PQ plot?
Conclusion. The p-q diagram is a method of simplifying the analysis of triaxial and other stress data which are commonly used in soil mechanics. It can be used in a variety of applications and solve a range of problems.
What is Cu in clay?
The undrained shear strength (cu) is considered one of the most basic para- meter characterizing soils in engineering practice. The particular importance of cu is in the case of clayey soil. This parameter also is the basis for the classification of soil according to the ISO standard.
Which triaxial test is best?
Unconsolidated – undrained (UU) triaxial test The unconsolidated – undrained triaxial test is the fastest test, typically completed under 30 minutes. It is performed on cohesive soil samples to determine the undrained shear strength of the core sample.
What is triaxial strength?
Triaxial shear strength test on soil measures the mechanical properties of the soil. In this test, soil sample is subjected to stress, such that the stress resulted in one direction will be different in perpendicular direction.
What is the triaxial shear test?
The triaxial shear test is the most versatile of all of the methods for testing the shear strength of soil and finding its cohesion (c) and angle of internal friction (φ). It can measure the total, as well as the effective stress parameters, and can be conducted on any type of soil.
How can I get a book on triaxial testing?
VJ Tech would recommend these books to any technician or laboratory undertaking triaxial tests. The books provide an in-depth understanding behind the theory of the test and also the testing procedures including quality control and analysis of the results. To purchase this book please contact the VJ Tech Sales department ( [email protected] ).
What is the most common triaxial test?
Finally, the consolidated undrained (CU) test is the most common triaxial procedure, as it allows strength parameters to be determined based on the effective stresses (i.e., φ’ and c’) while permitting a faster rate of shearing than the CD test.
What is a triaxial stress test?
· UU Triaxial – Unconsolidated Undrained (this can also be termed QU for Quick Undrained) UU triaxial tests are termed total stress tests and CU/CD triaxial tests are termed effective stress tests.