ASTM D2850-15

Standard Test Method for Unconsolidated-Undrained Triaxial Compression Test on Cohesive Soils

SIGNIFICANCE AND USE
4.1 In this test method, the compressive strength of a soil is determined in terms of the total stress, therefore, the resulting strength depends on the pressure developed in the pore fluid during loading. In this test method, fluid flow is not permitted from or into the soil specimen as the load is applied, therefore the resulting pore pressure, and hence strength, differs from that developed in the case where drainage can occur.  
4.2 If the test specimens is 100 % saturated, consolidation cannot occur when the confining pressure is applied nor during the shear portion of the test since drainage is not permitted. Therefore, if several specimens of the same material are tested, and if they are all at approximately the same water content and void ratio when they are tested, they will have approximately the same unconsolidated-undrained shear strength.  
4.3 If the test specimens are partially saturated, or compacted/reconstituted specimens, where the degree of saturation is less than 100 %, consolidation may occur when the confining pressure is applied and during application of axial load, even though drainage is not permitted. Therefore, if several partially saturated specimens of the same material are tested at different confining stresses, they will not have the same unconsolidated-undrained shear strength.  
4.4 Mohr failure envelopes may be plotted from a series of unconsolidated undrained triaxial tests. The Mohr’s circles at failure based on total stresses are constructed by plotting a half circle with a radius of half the principal stress difference (deviator stress) beginning at the axial stress (major principal stress) and ending at the confining stress (minor principal stress) on a graph with principal stresses as the abscissa and shear stress as the ordinate and equal scale in both directions. The failure envelopes will usually be a horizontal line for saturated specimens and a curved line for partially saturated specimens.  
4.5 The unconsolidated-u...
SCOPE
1.1 This test method covers determination of the strength and stress-strain relationships of a cylindrical specimen of either intact, compacted, or remolded cohesive soil. Specimens are subjected to a confining fluid pressure in a triaxial chamber. No drainage of the specimen is permitted during the application of the confining fluid pressure or during the compression phase of the test. The specimen is axially loaded at a constant rate of axial deformation (strain controlled).  
1.2 This test method provides data for determining undrained strength properties and stress-strain relations for soils. This test method provides for the measurement of the total stresses applied to the specimen, that is, the stresses are not corrected for pore-water pressure.
Note 1: The determination of the unconfined compressive strength of cohesive soils is covered by Test Method D2166/D2166M.
Note 2: The determination of the consolidated, undrained strength of cohesive soils with pore pressure measurement is covered by Test Method D4767.  
1.3 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.  
1.3.1 The procedures used to specify how data are collected/recorded or calculated in this standard are regarded as the industry standard. 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 considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design.  
1.4 Units—The values stated in SI units are to be regarded as the standard. The values given in parentheses are mathemat...

General Information

• Status: Historical
• Publication Date: 14-Nov-2015
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: D18 - Soil and Rock
• Drafting Committee: D18.05 - Strength and Compressibility of Soils

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D2850 − 15
Standard Test Method for
Unconsolidated-Undrained Triaxial Compression Test on
1
Cohesive Soils
This standard is issued under the fixed designation D2850; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* cal conversions to inch-pound units, which are provided for
information only and are not considered standard. Reporting of
1.1 This test method covers determination of the strength
test results in units other than SI shall not be regarded as
and stress-strain relationships of a cylindrical specimen of
nonconformance with this test method.
either intact, compacted, or remolded cohesive soil. Specimens
1.4.1 The converted inch-pound units use the gravitational
are subjected to a confining fluid pressure in a triaxial chamber.
system of units. In this system, the pound (lbf) represents a unit
No drainage of the specimen is permitted during the applica-
of force (weight), while the unit for mass is slugs. The slug unit
tion of the confining fluid pressure or during the compression
is not given, unless dynamic (F = ma) calculations are
phase of the test. The specimen is axially loaded at a constant
involved.
rate of axial deformation (strain controlled).
1.5 This standard does not purport to address all of the
1.2 This test method provides data for determining und-
safety concerns, if any, associated with its use. It is the
rained strength properties and stress-strain relations for soils.
responsibility of the user of this standard to establish appro-
This test method provides for the measurement of the total
priate safety and health practices and determine the applica-
stresses applied to the specimen, that is, the stresses are not
bility of regulatory limitations prior to use.
corrected for pore-water pressure.
NOTE 1—The determination of the unconfined compressive strength of
2. Referenced Documents
cohesive soils is covered by Test Method D2166/D2166M.
2
2.1 ASTM Standards:
NOTE 2—The determination of the consolidated, undrained strength of
D422 Test Method for Particle-Size Analysis of Soils
cohesive soils with pore pressure measurement is covered by Test Method
D4767.
D653 Terminology Relating to Soil, Rock, and Contained
Fluids
1.3 All observed and calculated values shall conform to the
D854 Test Methods for Specific Gravity of Soil Solids by
guidelines for significant digits and rounding established in
Water Pycnometer
Practice D6026.
D1587 Practice for Thin-Walled Tube Sampling of Soils for
1.3.1 The procedures used to specify how data are collected/
Geotechnical Purposes
recorded or calculated in this standard are regarded as the
D2166/D2166M Test Method for Unconfined Compressive
industry standard. In addition, they are representative of the
Strength of Cohesive Soil
significant digits that generally should be retained. The proce-
D2216 Test Methods for Laboratory Determination of Water
dures used do not consider material variation, purpose for
(Moisture) Content of Soil and Rock by Mass
obtaining the data, special purpose studies, or any consider-
D2487 Practice for Classification of Soils for Engineering
ations for the user’s objectives; and it is common practice to
Purposes (Unified Soil Classification System)
increase or reduce significant digits of reported data to be
D2488 Practice for Description and Identification of Soils
commensurate with these considerations. It is beyond the scope
(Visual-Manual Procedure)
of this standard to consider significant digits used in analysis
D3740 Practice for Minimum Requirements for Agencies
methods for engineering design.
Engaged in Testing and/or Inspection of Soil and Rock as
1.4 Units—The values stated in SI units are to be regarded
Used in Engineering Design and Construction
as the standard. The values given in parentheses are mathemati-
D4220/D4220M Practices for Preserving and Transporting
Soil Samples
1
This test method is under the jurisdiction of ASTM Committee D18 on Soil and
Rock and is the direct responsibility of Subcommittee D18.05 on Strength and
2
Compressibility of Soils. For referenced ASTM Standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 15, 2015. Published December 2015. Originally contact Customer Service at [e-mail]. For Annual Book of ASTM Stan-
approved in 1970. Last previous edition approved in 2007 as D2850 – 03a (2007). dardsvolume information, refer to the standard’s Document Summary page on the
DOI: 10.1520/D2850-15. ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Driv
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D2850 − 03a (Reapproved 2007) D2850 − 15
Standard Test Method for
Unconsolidated-Undrained Triaxial Compression Test on
1
Cohesive Soils
This standard is issued under the fixed designation D2850; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Scope*
1.1 This test method covers determination of the strength and stress-strain relationships of a cylindrical specimen of either
undisturbed intact, compacted, or remolded cohesive soil. Specimens are subjected to a confining fluid pressure in a triaxial
chamber. No drainage of the specimen is permitted during the application of the confining fluid pressure or during the compression
phase of the test. The specimen is sheared in compression without drainage axially loaded at a constant rate of axial deformation
(strain controlled).
1.2 This test method provides data for determining undrained strength properties and stress-strain relations for soils. This test
method provides for the measurement of the total stresses applied to the specimen, that is, the stresses are not corrected for
pore-water pressure.
NOTE 1—The determination of the unconfined compressive strength of cohesive soils is covered by Test Method D2166D2166/D2166M.
NOTE 2—The determination of the consolidated, undrained strength of cohesive soils with pore pressure measurement is covered by Test Method
D4767.
1.3 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D6026.
1.3.1 The methodprocedures used to specify how data are collected, calculated, collected/recorded or recordedcalculated in this
standard is not directly related to the accuracy to which the data can be applied in design or other uses, or both. How one applies
the results obtained using this standard is beyond its scope.are regarded as the industry standard. 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 considerations for the user’s objectives; and it is common practice to increase
or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard
to consider significant digits used in analysis methods for engineering design.
1.4 Units—The values stated in SI units are to be regarded as the standard. The values stated in inch-pound units and given in
parentheses are approximate.mathematical conversions to inch-pound units, which are provided for information 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.
1.4.1 The converted inch-pound units use the gravitational system of units. In this system, the pound (lbf) represents a unit of
force (weight), while the unit for mass is slugs. The slug unit is not given, unless dynamic (F = ma) calculations are involved.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. 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.
2. Referenced Documents
2
2.1 ASTM Standards:
D422 Test Method for Particle-Size Analysis of Soils
D653 Terminology Relating to Soil, Rock, and Contained Fluids
D854 Test Methods for Specific Gravity of Soil Solids by Water Pycnometer
D1587 Practice for Thin-Walled Tube Sampling of Soils for Geotechnical Purposes
1
This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.05 on Strength and
Compressibility of Soils.
Current edition approved Sept. 15, 2007Nov. 15, 2015. Published October 2007December 2015. Originally approved in 1970. Last previous edition approved in 20032007
as D2850 – 03a.D2850 – 03a (2007). DOI: 10.1520/D2850-03AR07.10.1520/D2850-15.
2
For referenced ASTM Standards, visit the ASTM website, www.astm.org, or contact Customer Service at [e-mail]. For Annual Book of ASTM Standardsvolume
information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears
...