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What is the unconfined compression test?

What is the unconfined compression test?

The Unconfined Compression Test is a laboratory test used to derive the Unconfirmed Compressive Strength (UCS) of a rock specimen. Unconfirmed Compressive Strength (UCS) stands for the maximum axial compressive stress that a specimen can bear under zero confining stress.

What is the size of UCS Mould?

Two-Part Compaction Mold Assemblies are used in Unconfined Compressive Strength testing of remolded cohesive soil specimens. Mold Assemblies are available in sizes ranging from 1.4 to 6in (35.6 to 152.4mm).

What are the advantages of unconfined compression test?

Advantages of Unconfined Compression Test: This test is very rapid. Inexpensive. In this test thin sample allows for rapid drainage of fine-grained soils.

What is the use of unconfined compressive strength?

The unconfined compression test is the most popular method of soil shear testing because it is one of the fastest and least expensive methods of measuring shear strength. It is used primarily for saturated, cohesive soils recovered from thin-walled sampling tubes.

How do you do the UCS test?

Test procedure

  1. Take two frictionless bearing plates of 75 mm diameter.
  2. Place the specimen on the base plate of the load frame (sandwiched between the end plates).
  3. Place a hardened steel ball on the bearing plate.
  4. Adjust the center line of the specimen such that the proving ring and the steel ball are in the same line.

What is UCS strength?

A measure of a material’s strength. The uniaxial compressive strength (UCS) is the maximum axial compressive stress that a right-cylindrical sample of material can withstand before failing. It is also known as the unconfined compressive strength of a material because confining stress is set to zero.

Is UCS a code test?

IS 2720
IS 2720 ( Part 10 ) : 1991 – Determination of Unconfined Compressive Strength. In this IS code detailed procedure of the calculations along with the apparatus used for performing laboratory unconfined compression test on clayey soil, undisturbed, remoulded or compacted, using controlled rate of strain is given.

What are the limitations of unconfined compression test?

3) Limitations of the unconfined compressive test i) Sample disturbance ( in case of samples obtained from thin wall tube) ii) Total and/or effective stress conditions in the field are not properly simulated.

Why is the unconfined compression test only used for clays?

The unconfined compression test is inappropriate for dry sands or crumbly clays because the materials would fall apart without some land of lateral confinement. To perform an unconfined compression test, the sample is extruded from the sampling tube.

How do you perform an unconfined compression test?

How is UCS value calculated?

The Unconfined Compressive Strength is calculated as

  1. Initial Area Of Specimen (A0) = π4D02.
  2. Change in Length or Deformetaion △L = Dail Reading in mm.
  3. Axial Strain (∈ ) = △LL0.
  4. Load (Kg) = Proving Ring Reading * Proving Ring Constant.
  5. Corrected Area = A01−∈cm2.
  6. Stress (δ ) = LoadCorrected Area Kg/cm2.

How is UCS rock calculated?

The UCS of the specimen is calculated by dividing the maximum load carried by the specimen during the test, by the average cross sectional area.

What is UCS in civil engineering?

Introduction. The uniaxial compressive strength (UCS) of rock is one of the most frequently used rock properties in civil and mining engineering practices.

When would the results of the unconfined compression test be used?

The unconfined test is used for cohesive, saturated soils. This test is inappropriate for dry sand or crumbly clays. This is essentially a special case of the triaxial compression test where the minor principal stress is zero.

How is unconfined compressive strength determined?

The unconfined compressive strength (qu) is the load per unit area at which the cylindrical specimen of a cohesive soil falls in compression. Where P= axial load at failure, A= corrected area = , where is the initial area of the specimen, = axial strain = change in length/original length.