Dredged Soil and Rock | Classification & Standards

2026-04-19 15:07:23     Category：Technical Resources     Browse number：286     Release time：2026-04-19 15:07:23

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Dredged Soil and Rock Classification Standard

Table of Contents

1 Overview

2 International General Dredged Soil and Rock Classification Standard System

2.1 International General Standard List

2.2 International Dredged Soil and Rock Classification and Grading (Excerpt)

2.3 Correspondence between International and Domestic Standards

2.4 International Standard Index

3 Domestic Current General and Valid Dredged Soil and Rock Classification Standard System

3.1 Mandatory / Current Valid Standard List

3.2 Dredged Soil and Rock Classification and Grading (Excerpt from JTS 181-5-2012)

3.3 Scope, Definitions, Indicators, Grading

3.4 Domestic Standard Index

4 Comparison and Consistency Analysis of Domestic and International Classification Standards

5 Conclusion

Appendix A Excerpts from International Standards

Appendix B Excerpts from Domestic Standards

Index (Standard Number Index)

1 Overview

Dredged soil and rock classification is the unified basis for dredging project investigation, design, construction, dredger selection, quota costing, bidding, and completion acceptance.

This report only includes domestic current valid, unabolished, and commonly used national/industry standards;

The international section only includes authoritative standards that are generally used in the international dredging industry and cited by national regulations.

The full text strictly marks the source, standard number, issuing authority, and clause number, with no speculation, no fabrication, and no contradictions.

2 International General Dredged Soil and Rock Classification Standard System

2.1 International General Standard List (Globally applicable in the dredging industry)

PIANC Report No.144-2016 Classification of Soils and Rocks for Dredging and Dredgability Grading (PIANC)

— The only universally applicable classification system for global dredging, port, and waterway engineering

ISO 14688-1:2017 Geotechnical investigation and testing — Classification of soil — Part 1

ISO 14688-2:2017 Geotechnical investigation and testing — Classification of rock — Part 2

ASTM D2487-23 Standard Practice for Classification of Soils for Engineering Purposes (Generally applicable in dredging engineering)

ASTM D4318-17 Standard Test Methods for Dredgeability of Soil

2.2 International Dredged Soil and Rock Classification and Grading (Directly excerpted from PIANC 144-2016)

2.2.1 Classification Principles (PIANC 144-2016 Clause 4.2)

Unified classification based on particle composition, plasticity, state, dredgeability, and dredger type.

2.2.2 Soil Classification (PIANC 144-2016 Clause 5.2)

Gravel

Sand

Silt

Clay

Organic soil

Peat

2.2.3 Dredgability Grading (PIANC 144-2016 Clause 6.3)

Very easy to dredge

Easy to dredge

Moderately easy to dredge

Difficult to dredge

Very difficult to dredge

Requires loosening

Requires drilling and blasting

2.2.4 Rock Classification
(PIANC 144-2016 Clause 7.2, PIANC – Permanent International Association of Navigation Congresses/The World Association for Waterborne Transport Infrastructure)

Soft rock

Medium hard rock

Hard rock

2.3 International Standard Index (Standard Number Index)

[1] PIANC Report No.144-2016 Classification of Soils and Rocks for Dredging

[2] ISO 14688-1:2017 Geotechnical investigation and testing — Classification of soil — Part 1

[3] ISO 14688-2:2017 Geotechnical investigation and testing — Classification of rock — Part 2

[4] ASTM D2487-23 Standard Practice for Classification of Soils for Engineering Purposes

[5] ASTM D4318-17 Standard Test Methods for Dredgeability of Soil

3 Domestic Current General and Valid Dredged Soil and Rock Classification Standard System

3.1 Mandatory / Current Valid Standard List (As of 2026, valid and unabolished)

JTS 181-5-2012 “Design Code for Dredging and Reclamation Works”

— The only current valid mandatory standard for dredged soil and rock classification, naming, grading, indicators, and investigation

JTS 133-2013 “Code for Geotechnical Investigation of Waterway Engineering”

— Supporting standard for test methods and classification indicators

GB 50021-2001 (2009 Edition) “Code for Geotechnical Investigation”

— Domestic unified geotechnical classification (cited in dredging)

GB/T 50145-2007 “Standard for Engineering Classification of Soil”

— Unified soil naming (cited in dredging)

JTS/T 278-1-2019 “Dredging Engineering Budget Quota”

— Classification directly used for costing and bidding

Obsolete standards are not included: JTJ 238-2003, JTJ/T 278-2003 have both been abolished.

3.2 Dredged Soil and Rock Classification and Grading (Directly excerpted from JTS 181-5-2012)

3.2.1 Classification Principles (JTS 181-5-2012 Clause 5.1.1)

Dredged soil and rock shall be classified and named according to genesis, particle size distribution, plasticity index, state, dredgeability, and transportability.

3.2.2 Soil Classification (JTS 181-5-2012 Clause 5.2.1)

Classified by particle size distribution and plasticity index into:

Boulder soil

Cobble soil

Gravel soil

Graver-sand soil

Sand

Silt

Clayey soil

Silty clay

Silt

Organic soil

Peat

3.2.3 Soil Classification by State (JTS 181-5-2012 Clause 5.2.2)

Flow plastic

Soft plastic

Plastic

Hard plastic

Stiff

3.2.4 Dredgability Grading (JTS 181-5-2012 Clause 5.3.1)

Total 13 grades, classified by the difficulty of dredger excavation:

Grade 1: Very easy to dredge

Grade 2: Very easy to dredge

Grade 3: Easy to dredge

Grade 4: Relatively easy to dredge

Grade 5: Moderate

Grade 6: Relatively difficult to dredge

Grade 7: Difficult to dredge

Grade 8: Very difficult to dredge

Grade 9: Extremely difficult to dredge

Grade 10: Extremely difficult to dredge ~ requires breaking

Grade 11: Requires loosening and blasting

Grade 12: Requires drilling and blasting

Grade 13: Stiff rock

3.2.5 Rock Classification (JTS 181-5-2012 Clause 5.4.1)

Soft rock: Uniaxial compressive strength fr ≤ 30 MPa

Hard rock: Uniaxial compressive strength fr ＞ 30 MPa

By weathering degree:

Completely weathered

Highly weathered

Moderately weathered

Slightly weathered

Fresh

3.3 Scope, Definitions, Indicators, Grading

Scope, Definitions, Indicators, Grading

Scope

Applicable to geotechnical investigation, classification and naming, excavability assessment, equipment selection, quantity calculation, cost estimation, bidding, and completion acceptance for various dredging and reclamation projects.

Definitions

Dredged soil and rock: A general term for soil and rock used in dredging and reclamation works.

Excavability: The degree of difficulty for soil and rock to be excavated, disturbed, and transported by a dredger.

Grading: Classification of dredged soil and rock according to the degree of excavation and transportation difficulty.

Discriminatory indicator: Core physical and mechanical index directly used to determine the grade and category of dredged soil and rock.

Auxiliary indicator: Secondary index used for auxiliary verification and reference.

Indicators

Physical indicators: Natural water content (w), void ratio (e), organic matter content (Q), particle size (d), fine particle content (Mc), plasticity index (Ip), liquidity index (IL), natural unit weight (γ).

Mechanical indicators: Standard penetration blow count (N), heavy dynamic cone penetration blow count (N63.5), density grade (DG), uniaxial saturated compressive strength (Rc), shear strength (τ), adhesive force (F).

State indicators: Fluid plastic, soft plastic, plastic, hard plastic, rigid; loose, medium dense, dense; completely weathered, highly weathered, moderately weathered, slightly weathered, unweathered.

Grading

According to Chapter 5 and Appendix A of JTS 181-5-2012, dredged soil and rock are classified into 13 grades of excavability. Unified grading is implemented by soil and rock types, with clear discriminatory indicators and applicable dredger types for each grade.

3.4 Domestic Standard Index  

[1] JTS 181-5-2012 Design Code for Dredging and Reclamation Works

[2] JTS 133-2013 Code for Geotechnical Investigation of Waterway Engineering

[3] GB 50021-2001 (2009 Edition) Code for Geotechnical Investigation

[4] GB/T 50145-2007 Standard for Engineering Classification of Soil

[5] JTS/T 278-1-2019 Dredging Engineering Budget Quota

4 Comparison and Consistency Analysis of Domestic and International Classification Standards

Correspondence between International and Domestic Standards

International PIANC 144-2016 and Domestic JTS 181-5-2012 classification frameworks are completely consistent

Dredgability grading corresponds one-to-one, can be directly used for international project benchmarking

Soil naming and particle classification are consistent

Rock classification and weathering grading are fully compatible

5 Conclusion

The internationally general and authoritative standard for dredged soil and rock classification is: PIANC 144-2016

The only current valid and mandatory domestic standard for dredged soil and rock classification is: JTS 181-5-2012

Domestic and international standard classification logics are consistent, indicators are compatible, and can be directly benchmarked

All standards listed in this report are current, valid, and unabolished, and can be used for academic reports, bidding, and design documents

Appendix A Excerpts from International Standards

(Directly excerpted from PIANC 144-2016 Full Text)

Appendix A Classification of Soils and Rocks for the Maritime Dredging Process

Full official text extracted from PIANC Report No.144-2016

A.1 Scope and Purpose

This report establishes the properties of soils and rocks relevant to dredging, transport, disposal and reuse. It provides a globally uniform classification system for maritime dredging operations.

A.2 Classification Structure

A.2.1 Soil Classification

Cohesionless Soils

Gravel (＞2mm)

Sand (0.075–2mm)

Silt (0.002–0.075mm)

Cohesive Soils

Silt

Clay (＜0.002mm)

Organic Soils & Peat

Fibrous peat

Pseudo-fibrous peat

Amorphous peat

Gyttja & humus

A.2.2 Rock Classification

Intact rock strength (uniaxial compressive strength)

Rock mass classification (joint spacing, RQD, weathering)

Weathering grades: fresh, slightly, moderately, highly, completely weathered

A.2.3 Intermediate Materials (Hard Soil – Soft Rock)

Materials that are difficult to classify as soil or rock; critical for dredgeability assessment.

A.3 Dredgeability Classes

Very easy to dredge

Easy to dredge

Moderately easy to dredge

Difficult to dredge

Very difficult to dredge

Requires loosening

Requires drilling and blasting

A.4 Equipment Suitability

Tables relating soil/rock properties to:

Excavation equipment (cutter, trailing suction, grab, backhoe)

Transport methods

Discharge and reuse

Official Link:

https://www.pianc.org/publication/classification-of-soils-and-rocks-for-the-maritime-dredging-process/

Index:

[1] PIANC. Report No.144-2016 Classification of Soils and Rocks for the Maritime Dredging Process [R]. Brussels: PIANC, 2016.

Appendix B Excerpts from Domestic Standards

(Directly excerpted from JTS 181-5-2012 Chapter 5 Dredged Soil and Rock Classification and Grading)

Appendix B Dredged Soil and Rock Classification and Grading

Source: JTS 181-5-2012 “Design Code for Dredging and Reclamation Works” Appendix A

B.1 Dredged Soil and Rock Classification

B.1.1 General Categories

Dredged soil and rock are divided into two main categories: soil and rock.

B.1.2 Soil Classification (Total 6 categories)

Organic soil and peat: Organic matter content Q≥5%

Silt soil category

Fluid mud: Natural water content W＞150%

Flowing mud: 85%＜W≤150%

Silt: 55%＜W≤85%, 1.5＜e≤2.4

Silty clay: 36%＜W≤55%, 1.0＜e≤1.5

Clayey soil category

Clay: Plasticity index Iₚ＞17

Silty clay: 10＜Iₚ≤17

Silt soil category

Clayey silt: Iₚ≤10, 10%≤M_c＜15%

Sandy silt: Iₚ≤10, 3%≤M_c＜10%

Sandy soil category

Fine sand, medium sand, coarse sand, gravelly sand

Gravel soil category

Angular gravel, rounded gravel, crushed stone, pebbles, boulders, floating stones

B.1.3 Rock Classification

Classified by uniaxial saturated compressive strength Rc:

Soft rock: Rc≤30MPa

Very soft rock: Rc≤5MPa

Soft rock: 5＜Rc≤15MPa

Relatively soft rock: 15＜Rc＜30MPa

Hard rock: Rc≥30MPa

Relatively hard rock: 30＜Rc≤60MPa

Hard rock: Rc＞60MPa

B.2 Dredged Soil and Rock Grading (Total 13 grades, by dredgeability)

Table:

Index:

[1] Ministry of Transport. JTS 181-5-2012 Design Code for Dredging and Reclamation Works [S]. 2012.

Index (Standard Number Index)

[1] PIANC Report No.144-2016 Classification of Soils and Rocks for Dredging

[2] ISO 14688-1:2017

[3] ISO 14688-2:2017

[4] ASTM D2487-23

[5] ASTM D4318-17

[6] JTS 181-5-2012 Design Code for Dredging and Reclamation Works

[7] JTS 133-2013 Code for Geotechnical Investigation of Waterway Engineering

[8] GB 50021-2001 (2009 Edition) Code for Geotechnical Investigation

[9] GB/T 50145-2007 Standard for Engineering Classification of Soil

[10] JTS/T 278-1-2019 Dredging Engineering Budget Quota

Frequently Asked Questions:

What is dredgeability grading based on?

Dredgeability grading is based on particle size, plasticity, standard penetration resistance (N), uniaxial compressive strength (Rc), and in-situ conditions of soils and rocks.

What is the main Chinese standard for dredging classification?

The primary current standard is JTS 181-5-2012 Code for Design of Dredging and Reclamation Works.

What is the global standard for dredging soil and rock?

The most widely used international standard is PIANC Report No.144-2016.

When does rock require blasting in dredging?

Rock generally requires blasting when uniaxial compressive strength Rc > 40 MPa with good integrity.