ASTM D6032/D6032M-17

Standard Test Method for Determining Rock Quality Designation (RQD) of Rock Core

SIGNIFICANCE AND USE
5.1 The RQD was first introduced in the mid 1960s to provide a simple and inexpensive general indication of rock mass quality to predict tunneling conditions and support requirements. The recording of RQD has since become virtually standard practice in drill core logging for a wide variety of geotechnical explorations.  
5.2 The use of RQD values has been expanded to provide a basis for making preliminary design and constructability decisions involving excavation for foundations of structures, or tunnels, open pits, and many other applications. The RQD values also can serve to identify potential problems related to bearing capacity, settlement, erosion, or sliding in rock foundations. The RQD can provide an indication of rock quality in quarries for issues involving concrete aggregate, rockfill, or large riprap.  
5.3 The RQD has been widely used as a warning indicator of low-quality rock zones that may need greater scrutiny or require additional borings or other investigational work. This includes rocks with certain time-dependent qualities that by determining the RQD again after 24 h, under well-controlled conditions, can assist in determining durability.  
5.4 The RQD is a basic component of many rock mass classification systems, such as rock mass rating (RMR) and Q-System, for engineering purposes. See D5878 and 2,3.  
5.5 When needed, drill holes in different directions can be used to determine the RQD in three dimensions.  
5.6 The concept of RQD can be used on any rock outcrop or excavation surface using line surveys as well. However, this topic is not covered by this standard.
Note 2: The quality of the result 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 and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with...
SCOPE
1.1 This test method covers the determination of the rock quality designation (RQD) as a standard parameter in drill core logging of a core sample in addition to the commonly obtained core recovery value (Practice D2113); however there may be some variations between different disciplines, such as mining and civil projects.  
1.2 This standard does not cover any RQD determinations made by other borehole methods (such as acoustic or optical televiewer) and which may not give the same data or results as on the actual core sample(s).  
1.3 There are many drilling and lithologic variations that could affect the RQD results. This standard provides examples of many common and some unusual situations that the user of this standard needs to understand to use this standard and cannot expect it to be all inclusive for all drilling and logging scenarios. The intent is to provide a baseline of examples for the user to take ownership and watch for similar, additional or unique geological and procedural issues in their specific drilling programs.  
1.4 This standard uses the original calculation methods by D.U. Deere to determine an RQD value and does not cover other calculation or analysis methods; such as Monte Carlo.  
1.5 The RQD in this test method only denotes the percentage of intact and sound rock in a core interval, defined by the test program, and only of the rock mass in the direction of the drill hole axis, at a specific location. A core interval is typically a core run but can be a lithological unit or any other interval of core sample relevant to the project.  
1.6 RQD was originally introduced for use with conventional drilling of N-size core with diameter of 54.7 mm (2.155 in.). However, this test method covers all types of core barrels and core sizes from BQ to PQ, which are normally acceptable for measuring determining RQD as long as proper drilling techniques are used that do not cause excess core breakage or po...

General Information

• Status: Published
• Publication Date: 28-Feb-2017
• ICS: 13.080.99 - Other standards related to soil quality
• ICS: 73.100.30 - Equipment for drilling and mine excavation
• Technical Committee: D18 - Soil and Rock
• Drafting Committee: D18.12 - Rock Mechanics

Relations

• Replaces: ASTM D6032-08 - Standard Test Method for Determining Rock Quality Designation (RQD) of Rock Core
• Effective Date: 01-Mar-2017
• Refers: ASTM D3740-23 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Nov-2023
• Refers: ASTM D3740-19 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Oct-2019
• Refers: ASTM D653-14 - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Aug-2014
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM D3740-12a - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-May-2012
• Refers: ASTM D3740-12 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Mar-2012
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011
• Refers: ASTM D653-11 - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Sep-2011
• Refers: ASTM D3740-11 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Sep-2011
• Refers: ASTM D3740-10 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Mar-2010
• Refers: ASTM D653-09 - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Jan-2009
• Refers: ASTM D653-08a - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Dec-2008
• Refers: ASTM D653-08 - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Nov-2008
• Refers: ASTM D2113-08 - Standard Practice for Rock Core Drilling and Sampling of Rock for Site Investigation
• Effective Date: 01-Oct-2008

Overview

ASTM D6032/D6032M-17 is the standard test method for determining the Rock Quality Designation (RQD) of rock core samples. Developed by ASTM International, this standard establishes a uniform procedure for measuring and describing the quality of rock masses using core samples, primarily in geotechnical investigations, tunneling, mining, and construction projects involving rock foundations.

Originally introduced in the 1960s, RQD provides a simple and cost-effective way to indicate rock mass quality and help predict excavation and support requirements. Today, RQD logging is a well-established practice across a wide range of geotechnical and geological applications.

Key Topics

• Purpose and Scope: Defines the method for determining RQD as a parameter in drill core logging. The standard covers the calculation based exclusively on direct rock core samples, using only the original D.U. Deere methods.
• Significance: RQD offers a general, quantifiable measure of intact, sound rock within a core interval, providing insight into the mechanical integrity and suitability of the rock mass for engineering projects.
• Procedure Highlights:
  • Only measures intact and sound core pieces ≥100 mm (4 inches) in length.
  • Uses the centerline measurement method along the core axis.
  • Excludes weak, highly weathered, friable, or porous segments, as well as artificially induced breaks when feasible.
  • Recommends logging, documenting, and photographing core samples to support accurate RQD calculation.
• Versatility: The standard applies to all standard core barrel sizes (from BQ to PQ) and various rock types, noting special considerations for different drilling methods or lithological conditions.
• Assessment: Provides guidelines for reporting, calculation inconsistencies, and quality control, emphasizing the importance of trained personnel and appropriate sampling equipment.

Applications

• Tunneling and Underground Construction: RQD is critical for assessing rock mass quality, predicting tunneling conditions, and determining the requirements for ground support.
• Foundation Design: Engineers use RQD values to evaluate potential bearing capacity, settlement, or sliding issues for structures built on or in rock.
• Open Pit Mining and Large Excavations: RQD informs decisions about slope stability, blast design, and excavation methods.
• Quarry Operations: Helps identify rock formations suitable for aggregate, rockfill, or riprap production.
• Rock Mass Classification: RQD is a fundamental input for widely used rock mass classification systems like Rock Mass Rating (RMR) and the Q-System, which underpin many engineering designs and risk assessments.
• Warning Indicator: Identifies zones of low-quality rock that may warrant additional investigation, cautioning stakeholders about unexpected ground conditions.

Related Standards

For enhanced rock core assessment and geotechnical analysis, the following ASTM standards are often referenced alongside or in support of ASTM D6032/D6032M:

• ASTM D2113 – Practice for Rock Core Drilling and Sampling for Site Exploration
• ASTM D653 – Terminology Relating to Soil, Rock, and Contained Fluids
• ASTM D5878 – Guides for Using Rock-Mass Classification Systems for Engineering Purposes
• ASTM D3740 – Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock
• ASTM D6026 – Practice for Using Significant Digits in Geotechnical Data

Practical Value

Adhering to ASTM D6032/D6032M ensures consistent and objective measurement of rock mass quality, supporting reliable design and construction of tunnels, foundations, and other rock engineering projects. By standardizing RQD determination, stakeholders gain a universally recognized benchmark for comparing rock core quality, reducing uncertainty, and improving safety and efficiency across diverse geotechnical ventures.

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Keywords: RQD, rock quality designation, rock core, ASTM D6032, geotechnical exploration, core logging, tunneling, rock mass classification, foundation engineering, rock quality, mining standards.

Standards Content (Sample)

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.
Designation: D6032/D6032M − 17
Standard Test Method for
Determining Rock Quality Designation (RQD) of Rock Core
This standard is issued under the fixed designation D6032/D6032M; 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* techniques are used that do not cause excess core breakage or
poor recovery, or both. See 6.3 for more information on this
1.1 This test method covers the determination of the rock
issue.
quality designation (RQD) as a standard parameter in drill core
logging of a core sample in addition to the commonly obtained 1.7 Only the RQD classification which correlates with the
core recovery value (Practice D2113); however there may be common tunneling classification that was presented by
2,3
some variations between different disciplines, such as mining Deere is covered in this test method. Other classification
and civil projects. systems are not covered specifically but are mentioned in
general and if used shall not be regarded as nonconformance
1.2 This standard does not cover any RQD determinations
with this standard.
made by other borehole methods (such as acoustic or optical
televiewer) and which may not give the same data or results as 1.8 All observed and calculated values shall conform to the
on the actual core sample(s). guidelines for significant digits and rounding established in
Practice D6026.
1.3 There are many drilling and lithologic variations that
1.8.1 The method used to specify how data are collected,
could affect the RQD results. This standard provides examples
calculated, or recorded in this standard is not directly related to
of many common and some unusual situations that the user of
theaccuracytowhichthedatacanbeappliedindesignorother
this standard needs to understand to use this standard and
uses, or both. How one applies the results obtained using this
cannot expect it to be all inclusive for all drilling and logging
standard is beyond its scope.
scenarios. The intent is to provide a baseline of examples for
the user to take ownership and watch for similar, additional or 1.9 The values stated in either SI units or inch-pound units
unique geological and procedural issues in their specific [rational values are given in brackets] are to be regarded
drilling programs. separately as standard. The values stated in each system may
not be exact equivalents; therefore, each system shall be used
1.4 This standard uses the original calculation methods by
independently of the other. Combining values from the two
D.U. Deere to determine an RQD value and does not cover
systems may result in non-conformance with the standard.
other calculation or analysis methods; such as Monte Carlo.
Reporting of test results in units other than SI shall not be
1.5 The RQD in this test method only denotes the percent-
regarded as nonconformance with this standard.
age of intact and sound rock in a core interval, defined by the
1.10 This standard does not purport to address all of the
test program, and only of the rock mass in the direction of the
safety concerns, if any, associated with its use. It is the
drill hole axis, at a specific location.Acore interval is typically
responsibility of the user of this standard to establish appro-
a core run but can be a lithological unit or any other interval of
priate safety and health practices and determine the applica-
core sample relevant to the project.
bility of regulatory limitations prior to use.
1.6 RQD was originally introduced for use with conven-
1.11 This international standard was developed in accor-
tional drilling of N-size core with diameter of 54.7 mm (2.155
dance with internationally recognized principles on standard-
in.). However, this test method covers all types of core barrels
ization established in the Decision on Principles for the
and core sizes from BQ to PQ, which are normally acceptable
for measuring determining RQD as long as proper drilling
Deere, D. U., and Deere, D. W., The Rock Quality Designation (RQD) After
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland Twenty Years, Rock Classification Systems for Engineering Purposes, ASTM STP
Rock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics. 984, 1988, pp. 91–101.
Current edition approved March 1, 2017. Published April 2017. Originally Deere, D. U., and Deere, D. W., Rock Quality Designation (RQD) Index in
approved in 1996. Last previous edition approved in 2008 as D6032 – 08. DOI: Practice, Contract Report G1–89–1, Department of the Army Corps of Engineers,
10.1520/D6032_D6032M-17. 1989.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6032/D6032M − 17
Development of International Standards, Guides and Recom- which drilling stopped and the core barrel was retrieved to
mendations issued by the World Trade Organization Technical recover the cored sample.
Barriers to Trade (TBT) Committee. 3.2.5.1 Discussion—If required, the core run used to calcu-
late the RQD can also be defined to cover a specific interval or
2. Referenced Documents
lithology in the core samples. The length of the core run may
not be equal to the length of the core sample retrieved if there
2.1 ASTM Standards:
is any core loss or void(s) in the coring interval or if a stub of
D653 Terminology Relating to Soil, Rock, and Contained
core is left at the bottom of the drill hole. Any core sample or
Fluids
stub left at the bottom of the core run must be accounted for in
D2113 Practice for Rock Core Drilling and Sampling of
a consistent manner in the drill logs and RQD calculations.
Rock for Site Exploration
D3740 Practice for Minimum Requirements for Agencies 3.2.6 discontinuity, n—in geomechanics, a general term
denoting any separation in a rock mass having zero or low
Engaged in Testing and/or Inspection of Soil and Rock as
Used in Engineering Design and Construction tensile strength and is the collective term for most types of
D5079 Practices for Preserving and Transporting Rock Core joints,fractures,weakbeddingplanes,weakschistocityplanes,
Samples (Withdrawn 2017) weakness zones, and shears.
D5878 Guides for Using Rock-Mass Classification Systems
3.2.7 drill break, n—in drilling, any mechanical or man-
for Engineering Purposes
made break in the core that was not naturally occurring.
D6026 Practice for Using Significant Digits in Geotechnical
3.2.8 fully circular method, n—in geomechanics, measure-
Data
ment of the core length only where the core has a full circular
E691 Practice for Conducting an Interlaboratory Study to
cross section along the core axis. See Appendix X1.
Determine the Precision of a Test Method
3.2.9 intact core, n—in geomechanics, any segment of core
between two open/unbonded, natural or mechanical disconti-
3. Terminology
nuities.
3.1 Definitions:
3.2.10 rock quality designation (RQD), n—in
3.1.1 For definitions of common technical terms in this
geomechanics, a modified core recovery in which the ratio of
standard, refer to Terminology D653.
length of core recovered to the total length drilled is modified
3.2 Definitions of Terms Specific to This Standard:
such that only the length of the pieces of sound core that are
3.2.1 artificial core run, n—runlengths,orintervals,created
equal to or greater than 100 mm [4 in.] in length, as measured
when logging the core to identify different zones or patterns of
along the core axis, are counted towards the length of core
RQD in the rock mass.
recovered, and this ratio is expressed as a percent.
3.2.2 centerline method, n—length of core sample measured
3.2.11 sound core, n—in rock drilling, any core that is
along the centerline (core axis); see Appendix X1.
unweathered to moderately weathered and has sufficient
3.2.3 core discing, n—in rock mechanics, a phenomenon in
strength to resist hand breakage.
which the drilled core breaks into disks with uniform spacing 3.2.11.1 Discussion—Most engineers and geologist under-
and shape due to the transient stress changes, and stress release
stand what unweathered means but there is no one standard or
during drilling. definitions for “moderately weathered” or “resist hand break-
age” and varies in the literature. However, most drillers and
3.2.4 corerecovery,n—inrockdrilling,theratiooflengthof
persons logging core usually have a good idea what either one
coresamplerecovered,bothweatheredandunweathered,tothe
means and would not be abused or would follow standard
length drilled, and expressed as a percent.
operating procedures used by their company. In general, hand
3.2.4.1 Discussion—Some literature is using a term called
breakage means something that cannot be indented with a
“total core recovery” to replace this definition. The added term
finger nail and crumbles under firm blows with sharp end of a
“total” is an attempt to promote other types of core recovery
geological pick. Moderately weathered can vary in the litera-
definitions, one of which is “solid core recovery” and which is
ture. ISRM definitions for weathering were used for this
discussed in this standard and shown in the appendix to be
standard.
technically flawed and should be discouraged. Therefore, it
3.2.12 moderately weathered, n—in geology, less than half
was decided to stay with a definition that is already recognized
and has been used for many years in the drilling industry. of the rock material is decomposed and/or disintegrated to a
soil; fresh or discolored rock is present either as a continuous
3.2.5 core run, n—in rock drilling, in the most basic usage,
framework or as core stones.
the length of the interval measured from the depth at which
3.2.13 tip to tip method, n—in geomechanics, measurement
drilling to obtain a core sample was started to the depth at
of the core length as the distance between the highest point of
the piece of the core along the borehole. See Appendix.
3.2.13.1 Discussion—This definition is only provide be-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
cause it is used in the standard for discussions on why this
Standards volume information, refer to the standard’s Document Summary page on
measurement method is not used or approved by this standard
the ASTM website.
and does not infer that the method is valid or applicable for
The last approved version of this historical standard is referenced on
www.astm.org. RQD measurements
D6032/D6032M − 17
4. Summary of Test Method 5.3 The RQD has been widely used as a warning indicator
of low-quality rock zones that may need greater scrutiny or
4.1 The RQD denotes the percentage of intact and sound
require additional borings or other investigational work. This
rock retrieved from a borehole orientated in any direction. All
includes rocks with certain time-dependent qualities that by
pieces of intact and sound rock core equal to or greater than
determining the RQD again after 24 h, under well-controlled
100 mm [4 in.] long are identified and recorded.The pieces are
conditions, can assist in determining durability.
measured along the core axis (centerline method).
5.4 The RQD is a basic component of many rock mass
NOTE 1—The original paper by Deere states “over four inches” and
classification systems, such as rock mass rating (RMR) and
many references vary between “over 4 inches” to “equal to or greater than
2,3
Q-System, for engineering purposes. See D5878 and .
4 inches”. This issue was posed to the D18.12 membership and the
consensus was that the way it is typically been used in the field, equal to
5.5 When needed, drill holes in different directions can be
orgreaterthan100-mm[4in.]ishowitshouldbewordedinthisstandard.
used to determine the RQD in three dimensions.
References like Wikipedia do not always have the best information either
and should not be assumed to be correct much less a consensus on this
5.6 TheconceptofRQDcanbeusedonanyrockoutcropor
issue.
excavation surface using line surveys as well. However, this
4.2 Pieces of core that are moderately or intensely topic is not covered by this standard.
NOTE 2—The quality of the result produced by this standard is
weathered, contain numerous pores, or are friable, or any
dependent on the competence of the personnel performing it, and the
combination thereof, should not be included in the summation
suitability of the equipment and facilities used. Agencies that meet the
of pieces for the determination of the RQD. Where the core is
criteria of Practice D3740 are generally considered capable of competent
known or believed to have been broken by handling or by the
and objective testing/sampling/inspection/etc. Users of this standard are
drilling process, the broken pieces (including core discing) are cautioned that compliance with Practice D3740 does not in itself assure
reliable results. Reliable results depend on many factors; Practice D3740
fittedtogetherandcountedasonepieceandthepiecesarefitted
provides a means of evaluating some of those factors.
together, marked as a mechanical break (both on the cores and
on the logs) and counted as one piece.
6. Interferences
4.3 All the sections of core that meet the greater than or
6.1 Usedalone,RQDisnotsufficienttoprovideanadequate
equalto100-mm[4inches]andsoundnesscriteriaaresummed
description of rock mass quality. The RQD does not account
and then divided by the total length of the core run or interval
for discontinuity orientation, tightness, continuity, and gouge
of interest (see 4.3.1), as shown in Fig. 1, to give the value of
material. The RQD must be used in combination with other
RQD as a percent. Rock mechanics judgment may be neces-
geological and geotechnical input.
sary to determine if a piece of core qualifies as being intact and
6.2 The RQD is sensitive to the orientation of joint sets or
sound.
other open or weak discontinuities with respect to the orienta-
4.3.1 If required, the RQD may be determined for intervals
tion of the core axis. For example, a joint set parallel to the
otherthanagivencorerun.Forexample,determiningtheRQD
core axis may not, if at all, intersect the core sample, unless the
for a given rock unit, rock type, a running value, or weighted
drill hole axis happens to run along the joint plane. A joint set
average.
perpendicular to the core axis will intersect the core axis at
4.4 TheRQDvalueisthenusedforclassificationoftherock
intervals equal to the joint spacing. For intermediate
quality based upon a rating system, such as the one in Deere’s
orientations, the spacing of discontinuity intersections with the
original paper and shown in Fig. 1 and is usually the default
core will be a cosine function of angle between joints and the
system to use. Some other classification system might be used,
core axis.
if required, at the drill site or later on in the data analysis
6.3 The N-size are the optimal core barrel size for deter-
process.
mining RQD.The RQD is also useful for larger core diameters
provided the core diameter is clearly stated. The RQD calcu-
5. Significance and Use
lated for core smaller than BQ may not be representative of the
5.1 The RQD was first introduced in the mid 1960s to true quality of the rock mass. Larger sizes are preferred; and
provide a simple and inexpensive general indication of rock the smaller BQ and BWX sizes should be discouraged and;
mass quality to predict tunneling conditions and support when used, should be identified with a disclaimer.
requirements. The recording of RQD has since become virtu-
6.4 The RQD values obtained can be sensitive to the type of
ally standard practice in drill core logging for a wide variety of
drill equipment and techniques that are used. Double or triple,
geotechnical explorations.
split tube, core barrels are preferred over single tube barrels.
5.2 The use of RQD values has been expanded to provide a Use of single tube core barrels will have additional issues to
consider when making RQD determinations. Therefore, it is
basis for making preliminary design and constructability deci-
sions involving excavation for foundations of structures, or important to note what type of drill equipment and techniques
were used as well as the personnel involved. Also, if conven-
tunnels, open pits, and many other applications. The RQD
tional drilling is used, rather than, wire line drilling, then the
values also can serve to identify potential problems related to
bearing capacity, settlement, erosion, or sliding in rock foun-
dations. The
...

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: D6032 − 08 D6032/D6032M − 17
Standard Test Method for
Determining Rock Quality Designation (RQD) of Rock Core
This standard is issued under the fixed designation D6032;D6032/D6032M; 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*
1.1 This test method covers the determination of the rock quality designation (RQD) as a standard parameter in drill core
logging. logging of a core sample in addition to the commonly obtained core recovery value (Practice D2113); however there may
be some variations between different disciplines, such as mining and civil projects.
1.2 This standard does not cover any RQD determinations made by other borehole methods (such as acoustic or optical
televiewer) and which may not give the same data or results as on the actual core sample(s).
1.3 There are many drilling and lithologic variations that could affect the RQD results. This standard provides examples of many
common and some unusual situations that the user of this standard needs to understand to use this standard and cannot expect it
to be all inclusive for all drilling and logging scenarios. The intent is to provide a baseline of examples for the user to take
ownership and watch for similar, additional or unique geological and procedural issues in their specific drilling programs.
1.4 This standard uses the original calculation methods by D.U. Deere to determine an RQD value and does not cover other
calculation or analysis methods; such as Monte Carlo.
1.5 The RQD in this test method only denotes the percentage of intact and sound rock in a core interval, defined by the test
program, and only of the rock mass in the direction of the drill hole axis, at a specific location. A core interval is typically a core
run but can be a lithological unit or any other interval of core sample relevant to the project.
1.6 RQD was originally introduced for use with conventional drilling of N-size core with diameter of 54.7 mm (2.155 in.).
However, this test method covers all types of core barrels and core sizes from BQ to PQ, which are normally acceptable for
measuring determining RQD as long as proper drilling techniques are used that do not cause excess core breakage or poor recovery,
or both. See 6.3 for more information on this issue.
2,3
1.7 Only the RQD classification which correlates with the common tunneling classification that was presented by Deere is
covered in this test method. Other classification systems are not covered specifically but are mentioned in general and if used shall
not be regarded as nonconformance with this standard.
1.8 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D6026.
1.8.1 The method used to specify how data are collected, calculated, or recorded 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.
1.9 The values stated in either SI units are or inch-pound units [rational values are given in brackets] are to be regarded
separately as the standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for
information only and are not considered stated in each system may not be exact equivalents; therefore, each system shall be used
independently of the other. Combining values from the two systems may result in non-conformance with the standard. Reporting
of test results in units other than SI shall not be regarded as nonconformance with this standard.
1.10 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.
This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.
Current edition approved July 1, 2008March 1, 2017. Published July 2008April 2017. Originally approved in 1996. Last previous edition approved in 20062008 as
D6032 – 02 (2006).D6032 – 08. DOI: 10.1520/D6032-08.10.1520/D6032_D6032M-17.
Deere, D. U., and Deere, D. W., The Rock Quality Designation (RQD) After Twenty Years, Rock Classification Systems for Engineering Purposes, ASTM STP 984, 1988,
pp. 91–101.
Deere, D. U., and Deere, D. W., Rock Quality Designation (RQD) Index in Practice, Contract Report G1–89–1, Department of the Army Corps of Engineers, 1989.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6032/D6032M − 17
1.11 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.
2. Referenced Documents
2.1 ASTM Standards:
D653 Terminology Relating to Soil, Rock, and Contained Fluids
D2113 Practice for Rock Core Drilling and Sampling of Rock for Site Exploration
D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in
Engineering Design and Construction
D5079 Practices for Preserving and Transporting Rock Core Samples (Withdrawn 2017)
D5878 Guides for Using Rock-Mass Classification Systems for Engineering Purposes
D6026 Practice for Using Significant Digits in Geotechnical Data
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 For terminology used in this test method, refer to Terminology D653.Definitions:
3.1.1 For definitions of common technical terms in this standard, refer to Terminology D653.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 artificial core run, n—run lengths, or intervals, created when logging the core to identify different zones or patterns of
RQD in the rock mass.
3.2.2 centerline method, n—length of core sample measured along the centerline (core axis); see Appendix X1.
3.2.3 core discing, n—in rock mechanics, a phenomenon in which the drilled core breaks into disks with uniform spacing and
shape due to the transient stress changes, and stress release during drilling.
3.2.4 core recovery, n—in rock drilling, the ratio of length of core sample recovered, both weathered and unweathered, to the
length drilled, and expressed as a percent.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
3.2.4.1 Discussion—
Some literature is using a term called “total core recovery” to replace this definition. The added term “total” is an attempt to
promote other types of core recovery definitions, one of which is “solid core recovery” and which is discussed in this standard and
shown in the appendix to be technically flawed and should be discouraged. Therefore, it was decided to stay with a definition that
is already recognized and has been used for many years in the drilling industry.
3.2.5 core run—run, n—in rock drilling, in the most basic usage, the length of the interval measured from the depth each at
which drilling to obtain a core sample was started to the depth at which drilling stopped and the sample was recovered from the
core barrel. If required, the core run can also be defined to cover a specific length or lithology in the core samples.core barrel was
retrieved to recover the cored sample.
3.2.5.1 Discussion—
If required, the core run used to calculate the RQD can also be defined to cover a specific interval or lithology in the core samples.
The length of the core run may not be equal to the length of the core sample retrieved if there is any core loss or void(s) in the
coring interval or if a stub of core is left at the bottom of the drill hole. Any core sample or stub left at the bottom of the core run
must be accounted for in a consistent manner in the drill logs and RQD calculations.
3.2.6 discontinuity, n—in geomechanics, a general term denoting any separation in a rock mass having zero or low tensile
strength and is the collective term for most types of joints, fractures, weak bedding planes, weak schistocity planes, weakness
zones, and shears.
3.2.7 drill break—break, n—in drilling, any mechanical or man-made break in the core that iswas not naturalnaturally occurring.
3.2.8 fully circular method, n—in geomechanics, measurement of the core length only where the core has a full circular cross
section along the core axis. See Appendix X1.
3.2.9 intact core—core, n—in geomechanics, any segment of core between two open,open/unbonded, natural or mechanical
discontinuities.
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3.2.10 rock quality designation (RQD)—(RQD), n—in geomechanics, a modified core recovery percentage in which all in which
the ratio of length of core recovered to the total length drilled is modified such that only the length of the pieces of sound core
over 100 mm are counted as recovery.that are equal to or greater than 100 mm [4 in.] in length, as measured along the core axis,
are counted towards the length of core recovered, and this ratio is expressed as a percent.
3.2.11 sound core—core, n—in rock drilling, any core whichthat is freshunweathered to moderately weathered and which has
sufficient strength to resist hand breakage.
3.2.11.1 Discussion—
Most engineers and geologist understand what unweathered means but there is no one standard or definitions for “moderately
weathered” or “resist hand breakage” and varies in the literature. However, most drillers and persons logging core usually have
a good idea what either one means and would not be abused or would follow standard operating procedures used by their company.
In general, hand breakage means something that cannot be indented with a finger nail and crumbles under firm blows with sharp
end of a geological pick. Moderately weathered can vary in the literature. ISRM definitions for weathering were used for this
standard.
3.2.12 moderately weathered, n—in geology, less than half of the rock material is decomposed and/or disintegrated to a soil;
fresh or discolored rock is present either as a continuous framework or as core stones.
3.2.13 tip to tip method, n—in geomechanics, measurement of the core length as the distance between the highest point of the
piece of the core along the borehole. See Appendix.
3.2.13.1 Discussion—
This definition is only provide because it is used in the standard for discussions on why this measurement method is not used or
approved by this standard and does not infer that the method is valid or applicable for RQD measurements
4. Summary of Test Method
4.1 The RQD denotes the percentage of intact and sound rock retrieved from a borehole orientated in any direction. All pieces
of intact and sound rock core equal to or greater than 100 mm [4 in.] long are identified and recorded. The pieces are measured
along the core axis (centerline method).
NOTE 1—The original paper by Deere states “over four inches” and many references vary between “over 4 inches” to “equal to or greater than 4 inches”.
This issue was posed to the D18.12 membership and the consensus was that the way it is typically been used in the field, equal to or greater than 100-mm
[4 in.] is how it should be worded in this standard. References like Wikipedia do not always have the best information either and should not be assumed
to be correct much less a consensus on this issue.
4.2 Pieces of core that are moderately or intensely weathered, contain numerous pores, or are friable, or any combination
thereof, should not be included in the summation of pieces for the determination of the RQD. Where the core is known or believed
to have been broken by handling or by the drilling process, the broken pieces (including core discing) are fitted together and
counted as one piece and the pieces are fitted together, marked as a mechanical break (both on the cores and on the logs) and
counted as one piece.
4.3 The RQD denotes the percentage of intact and sound rock retrieved from a borehole of any orientation. All pieces of intact
and sound rock core equal to or greater than 100 mm (4 in.) long All the sections of core that meet the greater than or equal to
100-mm [4 inches] and soundness criteria are summed and then divided by the total length of the core run, run or interval of interest
(see 4.3.1), as shown in Fig. 1. Rock mechanics judgement, to give the value of RQD as a percent. Rock mechanics judgment may
be necessary to determine if a piece of core qualifies as being intact and sound.
4.3.1 If required, the RQD may be determined for intervals other than a given core run. For example, determining the RQD for
a given rock unit, rock type, a running value, or weighted average.
4.4 The RQD value is then used for classification of the rock quality based upon a rating system, such as the one in Deere’s
original paper and shown in Fig. 1 and is usually the default system to use. Some other classification system might be used, if
required, at the drill site or later on in the data analysis process.
5. Significance and Use
5.1 The RQD was first introduced in the mid 1960s to provide a simple and inexpensive general indication of rock mass quality
to predict tunnellingtunneling conditions and support requirements. The recording of RQD has since become virtually standard
practice in drill core logging for a wide variety of geotechnical investigations.explorations.
5.2 The use of RQD values has been expanded to provide a basis for making preliminary design and constructability decisions
involving estimation of required depths of excavation for foundations of structures. structures, or tunnels, open pits, and many
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FIG. 1 RQD Logging Center Line MethodExample of How RQD Data is Collected for a Core Run or Interval, and Calculated, Using the
2,3
Centerline Method, and Then Classified. The rock quality classification shown is what was originally proposed by Deere . Other rock
quality classifications may be used.
other applications. The RQD values also can serve to identify potential problems related to bearing capacity, settlement, erosion,
or sliding in rock foundations. The RQD can provide an indication of rock quality in quarries for issues involving concrete
aggregate, rockfill, or large riprap.
5.3 The RQD has been widely used as a warning indicator of low-quality rock zones that may need greater scrutiny or require
additional borings or other investigational work. This includes rocks with certain time-dependent qualities that by determining the
RQD again after 24 h, under well-controlled conditions, can assist in determining durability.
5.4 The RQD is a basic component of many rock mass classification systems systems, such as rock mass rating (RMR) and
2,3
Q-System, for engineering purposes. See D5878 and .
5.5 Used alone, RQD is not sufficient to provide an adequate description of rock mass quality. The RQD does not account for
joint orientation, tightness, continuity, and gouge material. The RQD must be used in combination with other geological and
geotechnical input.When needed, drill holes in different directions can be used to determine the RQD in three dimensions.
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5.6 The RQD is sensitive to the orientation of joint sets with respect to the orientation of the core. That is, a joint set parallel
to the core axis will not intersect the core, unless the drill hole happens to run along the joint. A joint set perpendicular to the core
axis will intersect the core axis at intervals equal to the joint spacing. For intermediate orientations, the spacing of joint
intersections with the core will be a cosine function of angle between joints and the core axis.
5.6 Core sizes from BQ to PQ with core diameters of 36.5 mm (1.44 in.) and 85 mm (3.35 in.), respectively, are normally
acceptable for measuring RQD as long as proper drilling techniques are used that do not cause excess core breakage or poor
recovery, or both. The NX-size (54.7 mm [2.16 in.]) and NQ-size (47.5 mm [1.87 in.]) are the optimal core sizes for measuring
RQD. The RQD is also useful for large core diameters provided the core diameter is clearly stated. The RQD calculated for core
smaller than BQ may not be representative of the true quality of the rock mass.The concept of RQD can be used on any rock
outcrop or excavation surface using line surveys as well. However, this topic is not covered by this standard.
NOTE 1—The quality of the result 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 and objective
testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable
results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.
NOTE 2—The quality of the result 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 and objective
testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable
results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.
6. Interferences
6.1 Used alone, RQD is not sufficient to provide an adequate description of rock mass quality. The RQD does not account for
discontinuity orientation, tightness, continuity, and gouge material. The RQD must be used in combination with other geological
and geotechnical input.
6.2 The RQD is sensitive to the orientation of joint sets or other open or weak discontinuities with respect to the orientation
of the core axis. For example, a joint set parallel to the core axis may not, if at all, intersect the core sample, unless the drill hole
axis happens to run along the joint plane. A joint set perpendicular to the core axis will intersect the core axis at intervals equal
to the joint spacing. For intermediate orientations, the spacing of discontinuity intersections with the core will be a cosine function
of angle between joints and the core axis.
6.3 The N-size are the optimal core barrel size for determining RQD. The RQD is also useful for larger core diameters provided
the core diameter is clearly stated. The RQD calculated for core smaller than BQ may not be representative of the true quality of
the rock mass. Larger sizes are preferred; and the smaller BQ and BWX sizes should be discouraged and; when used, should be
identified with a disclaimer.
6.4 The RQD values obtained can be sensitive to the type of drill equipm
...