EN 17542-4:2026

• Abstract:

  This document specifies the test method for the determination of the magnitude of one-dimensional collapse that occurs when unsaturated soils are inundated with water. This method is used to determine two parameters related to the collapsibility of a soil: the collapse index and the collapse potential.; This test method specifies the technique for specimen preparation, the apparatus and the procedure for quantifying the amount of height change associated with collapse and procedures for reporting test results.; The procedure given in this test method is applicable to both undisturbed samples or remolded specimens. It is a one single sample test procedure.

• Status: Published
• Publication Date: 15-Sep-2026
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: CEN/TC 396 - Earthworks
• Drafting Committee: CEN/TC 396/WG 8 - Test methods
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 16-Sep-2026
• Due Date: 03-Sep-2026
• Completion Date: 16-Sep-2026
• Ref Project: kSIST FprEN 17542-4:2026 - Earthworks - Geotechnical laboratory tests - Part 4: Test method for measurement of collapse potential of soils

EN 17542-4 is a CEN European Standard for geotechnical laboratory testing in earthworks. It specifies a one-sample oedometer test method for measuring the collapse potential of unsaturated soils when they are inundated with water, and for reporting the collapse index and collapse potential. It is written for laboratories, geotechnical engineers, and others who need repeatable test results for soil assessment and design.

What does EN 17542-4 specify?

EN 17542-4 specifies the test method for determining the magnitude of one-dimensional collapse in unsaturated soils after wetting. It also sets out how to prepare the specimen, what apparatus to use, how to run the test, and what to report.

The document is organized into seven clauses:

• Scope
• Normative references
• Terms and definitions
• Apparatus
• Specimen specification
• Test method
• Test report

It also includes two informative annexes.

Annex	What it covers
A	Model test report, with example tables and example consolidation and void ratio curves
B	Example evaluation of the degree of collapse

The procedure applies to both undisturbed samples and remolded specimens. It uses one specimen for one test, which matters in practice because the result comes from the specific sample condition and loading history used in that test.

What are the key requirements of EN 17542-4?

Specimen and apparatus requirements

• EN 17542-4 requires apparatus in accordance with EN ISO 17892-5, and the porous stones shall be air-dried. In practice, this prevents unwanted water intake through capillarity and keeps the test conditions controlled.
• EN 17542-4 allows remolded, compacted, or undisturbed specimens, prepared in line with EN ISO 17892-5. In practice, the lab must identify how the specimen was made, because that affects the collapse response.

How the test is run

• EN 17542-4 uses a simple sample oedometer test. The specimen is loaded to a defined vertical stress before wetting, and that stress is selected for the design situation.
• EN 17542-4 states that if the appropriate stress is not known in advance, 200 kPa should be used as the reference value. In practice, this gives the lab a common stress level for comparison and for using Annex B.
• EN 17542-4 requires the initial wet mass and height to be recorded, then a seating stress of 5 kPa to be applied, followed by load increments typically increasing by a factor of two. In practice, this creates a known starting point and a controlled loading history.
• EN 17542-4 requires wetting from the bottom porous stone, with the water preferably taken from the same location as the sample, or otherwise distilled-deionized water. In practice, the water origin must be reported because it may influence the result.
• EN 17542-4 requires the post-wetting load stage to continue for at least 24 h or until primary consolidation is complete. In practice, the lab waits for the settlement response to stabilize before taking the final reading.

What has to be reported

• EN 17542-4 requires the test report to state the specimen origin or preparation route, the specimen dimensions, the oedometer cell description, the water source, and any deviation from the method. In practice, these details are needed to judge whether the result is comparable and fit for interpretation.
• EN 17542-4 requires the report to include initial and final water content, initial degree of saturation, dry unit weight, the applied vertical stress at inundation, compression plots, void ratio plots, and the calculated collapse index and collapse potential. In practice, these are the core outputs used to compare soils and support design decisions.

What terms does EN 17542-4 define?

EN 17542-4 formally defines three key terms and uses them throughout the method.

• Collapse - the decrease in height of a confined soil after wetting while it is under constant applied vertical stress.
• Collapse index, I_sc - the decrease in specimen height after flooding, expressed as a percentage of the specimen height before wetting.
• Collapse potential, I_pc - the percentage decrease in specimen height after wetting, referenced to the initial specimen height.
• Oedometer test - the one-dimensional loading test used here to apply stress, wet the specimen, and measure the height change.
• Primary consolidation - the stage after wetting when the test waits for the main settlement response to finish before final readings are taken.

Who uses EN 17542-4?

EN 17542-4 is used by geotechnical laboratories, site investigation teams, foundation designers, and earthworks specialists. It is relevant to quality managers and buyers who need a laboratory method for identifying collapsible soils and comparing results across projects.

In practice, these users apply it to characterize soil behavior after wetting, support design decisions for foundations and earthworks, and document laboratory results in a standard format. Contractors and consultants can also use it when project specifications call for collapse testing of unsaturated soils.

Which standards are used with EN 17542-4?

Standard	What it contributes
EN ISO 17892-1	Water content determination, used for the final water content in the report
EN ISO 17892-2	Bulk density determination, used for reporting soil condition
EN ISO 17892-5	Oedometer apparatus, specimen handling, and the loading and wetting procedure
EN ISO 22475-1	Sampling principles and sample origin information for tests on sampled soil

These references make EN 17542-4 part of a wider geotechnical testing chain: sampling, specimen characterization, and oedometer-based collapse measurement.

What does the EN 17542-4 document contain?

EN 17542-4 contains the test setup, the step-by-step test method, and a reporting checklist. Clause 7 sets out the information that must appear in the test report, including the plots used to show compression behavior and void ratio change.

Annex A provides a model test report with example tables and example consolidation and void ratio curves. Annex B gives an example scale for interpreting the degree of collapse, which helps readers turn the numerical collapse potential into a practical severity description.

SLOVENSKI STANDARD
oSIST prEN 17542-4:2025
01-december-2025
Zemeljska dela - Geotehnični laboratorijski preskusi - 4. del: Preskusna metoda za
merjenje potenciala zrušitve tal
Earthworks - Geotechnical laboratory tests - Part 4: Test method for measurement of
collapse potential of soils
Erdarbeiten - Geotechnische Laborversuche - Teil 4: Prüfmethode zur Messung des
Einsturzpotentials von Böden
Ta slovenski standard je istoveten z: prEN 17542-4
ICS:
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
oSIST prEN 17542-4:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 17542-4:2025
oSIST prEN 17542-4:2025
DRAFT
EUROPEAN STANDARD
prEN 17542-4
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2025
ICS 93.020
English Version
Earthworks - Geotechnical laboratory tests - Part 4: Test
method for measurement of collapse potential of soils
Erdarbeiten - Geotechnische Laborversuche - Teil 4:
Prüfmethode zur Messung des Einsturzpotentials von
Böden
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 396.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17542-4:2025 E
worldwide for CEN national Members.

oSIST prEN 17542-4:2025
prEN 17542-4:2025 (E)
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Apparatus . 6
5 Specimen specification . 6
6 Test method . 7
6.1 Description of the method . 7
6.2 Procedure . 7
7 Test report . 7
Annex A (informative) Measurement of collapse of soils according to prEN 17542-4 – Test report
............................................................................................................................................................................... 9
Annex B (informative) Evaluation of the degree of collapse . 13
Bibliography . 14

oSIST prEN 17542-4:2025
prEN 17542-4:2025 (E)
European foreword
This document (prEN 17542-4:2025) has been prepared by Technical Committee
CEN/TC 396 “Earthworks”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
oSIST prEN 17542-4:2025
prEN 17542-4:2025 (E)
Introduction
The collapse of a soil is the decrease of height that can occur when unsaturated soils are immersed. This
document defines the collapse index and the collapse potential that qualifies this phenomenon.
NOTE A collapsible soil can withstand relatively large applied vertical stress with small settlement while it has
a low water content and degree of saturation, but this soil will exhibit settlement (that could be large) after wetting
with no additional increase in stress.
oSIST prEN 17542-4:2025
prEN 17542-4:2025 (E)
1 Scope
This document specifies the test method for the determination of the magnitude of one-dimensional
collapse that occurs when unsaturated soils are inundated with water. This method is used to determine
two parameters related with the collapsibility of a soil: the collapse index and the collapse potential.
This test method specifies the technique for specimen preparation, the apparatus and the procedure for
quantifying the amount of height change associated with collapse and procedures for reporting test
results.
The procedure given in this test method is applicable to both undisturbed samples or remolded
specimens. It is a one single sample test procedure.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 17892-1, Geotechnical investigation and testing — Laboratory testing of soil — Part 1:
Determination of water content (ISO 17892-1)
EN ISO 17892-2, Geotechnical investigation and testing — Laboratory testing of soil — Part 2:
Determination of bulk density (ISO 17892-2)
EN ISO 17892-5, Geotechnical investigation and testing — Laboratory testing of soil — Part 5: Incremental
loading œdometer test (ISO 17892-5)
EN ISO 22475-1, Geotechnical investigation and testing — Sampling methods and groundwater
measurements — Part 1: Technical principles for the sampling of soil, rock and groundwater (ISO 22475-1)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
3.1
collapse
decrease in height of a confined soil with a given water content and a given dry unit weight after wetting
at a constant applied vertical stress
Note 1 to entry: This stress is to be determined as appropriate for the design situation.
3.2
collapse index
I
sc
decrease in height of a specimen consolidated to a given vertical stress after flooding, ex
...