3.1 Definitions in this standard are to be regarded as the correct ones for terms found in other ASTM standards of Committee D18. Certain terms may be found in more than one standard issued under the jurisdiction of this committee and many of these terms have been placed in this standard.

3.2 Terms that are defined in some textbooks may differ slightly from those in this terminology standard. Definitions in this terminology standard are to be regarded as correct for ASTM usage.

3.3 See Appendix X1 for References.

3.4 Definitions marked with (ISRM) are included for the convenience of the user and were taken directly from the International Society for Rock Mechanics (see X1.3).

3.5 A number of the definitions include symbols. The symbols appear in italics immediately after the name of the term.

3.5.1 No significance should be placed on the order in which the symbols are presented where two or more are given for an individual term.

3.5.2 The symbols presented are examples; therefore, other symbols are acceptable.

3.5.3 See Appendix X2 for ISRM Symbols.

3.6 A number of definitions indicate the units of measurements in brackets and which follow the symbol(s) if given. The applicable units are indicated by italic capital letters, as follows:
 D—Dimensionless
 F—Force, such as pound-force, ton-force, newton
 L—Length, such as inch, foot, millimeter, and meter4
 M—Mass, such as kilogram, gram
 T—Time, such as second, minute

3.6.1 Positive exponents designate multiples in the numerator. Negative exponents designate multiples in the denominator. Degrees of angle are indicated as “degrees.”

3.6.2 Expressing the units either in SI or the inch-pound system has been purposely omitted in order to leave the choice of the system and specific unit to the engineer and the particular application, for example:
 FL⁻²—may be expressed in pounds-force per square inch, kilopascals, tons per square foot, etc.
 LT⁻¹—may be expressed in feet per minute, meters per second, etc.

3.7 Where synonymous terms are cross-referenced, the definition is usually included with the earlier term alphabetically. Where this is not the case, the later term is the more significant.

3.8 Grouping of Definitions and Listing of Related Terms—To aide users in finding terms, this terminology standard provides grouping of definitions and listing of related terms.

3.8.1 Groupings—These groupings are presented in Table 1A.

TABLE 1A Listing of Groupings*

Aquifer

Coefficients: Earth

Consolidation

D18.24

Density

Head

Measurement

Principal Plane

Specific Gravity

Stress

Unit Weight

Wave

*Groupings can be editorially added or removed by the subcommittee chair as they are changed within D653.

3.8.1.1 Sub-Term Groupings—These groupings are presented in Table 1B.

TABLE 1B Listing of Sub-Term Groupings*

ASTM cement types

horizon or soil horizon

moisture equivalent

plastic equilibrium

shear failure or failure by rupture

site investigation

soil structure

*Groupings can be editorially added or removed by the subcommittee chair as they are changed within D653.

3.8.2 Listings (see Appendix X3)—The listing of related terms is given in Table 1C. This listing may include all of the terms defined within standards under the jurisdiction of a specific technical subcommittee, such as D18.14, D18.24, D18.25, and D18.26.

TABLE 1C Listing of Related Terms*

compaction

density

effective

specific gravity

unit weight

*Listings of related terms can be editorially added or removed by the subcommittee chair as they are changed within D653.

1.1 These definitions apply to many terms found in the Terminology section of standards of ASTM Committee D18.

1.2 This terminology standard defines terms related to soil, rock, and contained fluids found in the various sections of standards under the jurisdiction of ASTM Committee D18.

1.3 Definitions of terms relating to frozen soils are contained in Terminology D7099.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.