ASTM D2850-15
Standard Test Method for Unconsolidated-Undrained Triaxial Compression Test on Cohesive Soils

Standard No.

ASTM D2850-15

Release Date

2015

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM D2850-23

Latest

ASTM D2850-23

Scope

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 1008201;% 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 1008201;%, 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-undrained shear strength is applicable to situations where the loads are assumed to take place so rapidly that there is insufficient time for the induced pore-water pressure to dissipate and for consolidation to occur during the loading period (that is, drainage does not occur).

4.6 Compressive strengths determined using this procedure may not apply in cases where the loading conditions in the field differ significantly from those used in this test method.

Note 3: The quality of the results produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent testing. Users of this test method are cautioned that compliance with Practice D3740 does not ensure reliable results. Reliable results depend on several factors; Practice D3740 provides a means of evaluating some of those factors.

1.1 This test method covers determin......

ASTM D2850-15 Referenced Document

• ASTM D1587 Standard Practice for Thin-Walled Tube Sampling of Soils for Geotechnical Purposes
• ASTM D2166/D2166M Standard Test Method for Unconfined Compressive Strength of Cohesive Soil*， 2024-04-20 Update
• ASTM D2216 Standard Test Method for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass
• ASTM D2487 Standard Test Method for Classification Of Soils For Engineering Purposes
• ASTM D2488 Recommended Practice for Description Of Soils (Visual-Manual Procedure)
• ASTM D3740 Standard Practice for Minimum Requirements for Agencies Engaged in the Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• ASTM D422 Standard Test Method for Particle-Size Analysis of Soils
• ASTM D4220/D4220M Standard Practices for Preserving and Transporting Soil Samples
• ASTM D4318 Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils
• ASTM D4753 Standard Specification for Evaluating, Selecting, and Specifying Balances and Scales for Use in Soil, Rock, and Construction Materials Testing
• ASTM D4767 Standard Test Method for Consolidated Undrained Triaxial Compression Test for Cohesive Soils
• ASTM D6026 Standard Practice for Using Significant Digits in Geotechnical Data
• ASTM D653 Standard Terminology Relating to Soil, Rock, and Contained Fluids
• ASTM D6913 Standard Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis
• ASTM D854 Standard Test Methods for Specific Gravity of Soil Solids by the Water Displacement Method

ASTM D2850-15 history

• 2023 ASTM D2850-23 Standard Test Method for Unconsolidated-Undrained Triaxial Compression Test on Cohesive Soils
• 2015 ASTM D2850-15 Standard Test Method for Unconsolidated-Undrained Triaxial Compression Test on Cohesive Soils
• 2003 ASTM D2850-03a(2007) Standard Test Method for Unconsolidated-Undrained Triaxial Compression Test on Cohesive Soils
• 2003 ASTM D2850-03a Standard Test Method for Unconsolidated-Undrained Triaxial CompressionTest on Cohesive Soils
• 2003 ASTM D2850-03 Standard Test Method for Unconsolidated-Undrained Triaxial CompressionTest on Cohesive Soils
• 1999 ASTM D2850-95(1999) Standard Test Method for Unconsolidated-Undrained Triaxial CompressionTest on Cohesive Soils