Determining the Unconfined Compressive Strength of Cohesive Soil - Soil Properties: Testing, Measurement, and Evaluation - page 325

of strain in the report of the test data. Determine the water content
of the test specimen using the entire specimen, unless representa-
tive trimmings are obtained for this purpose, as in the case of
intact specimens. Indicate on the test report whether the water
content sample was obtained before or after the shear test.

Note 3 —Softer materials that will exhibit larger deforma-
tion at failure should be tested at a higher rate of strain.
Conversely, stiff or brittle materials that will exhibit small
deformations at failure should be tested at a lower rate of
strain.

(2) Make a sketch, or take a photo, of the test specimen at fail-
ure showing the slope angle of the failure surface if the angle is
measurable.

Data collected in this test should include the following:

DATA

[A] Specimen Data

Diameter of specimen, D 0 (in.)
Initial height of specimen, H 0 (in.)
Mass of specimen (g)
Water content data:
Mass of wet soil plus can (g)
Mass of dry soil plus can (g)
Mass of can (g)

[B] Compression Data

Successive load and deformation values as load is applied (loads are
determined by multiplying proving ring dial readings by the proving
ring calibration factor)

[A] Specimen Parameters

CALCULATIONS

With the diameter and initial height of the specimen known, its initial
area, volume, and height-to-diameter ratio can be calculated. With the
specimen's mass known, its wet unit weight can be found. From the
water content data, the water content (see Chapter 4) and then the dry
unit weight of the specimen can be determined.

[B] Compression Calculation

For each applied load, axial unit strain, , can be computed by dividing

e

the specimen's change in height, H by its initial height, H 0 . In equa-

Δ ,

tion form,