CEN ISO/TS 17892-7:2004

SLOVENSKI STANDARD
01-december-2004
*HRWHKQLþQRSUHLVNRYDQMHLQSUHVNXãDQMH/DERUDWRULMVNRSUHVNXãDQMH]HPOMLQ
GHO(QRRVQLWODþQLSUHVNXVGUREQR]UQDWLK]HPOMLQ,6276
Geotechnical investigation and testing - Laboratory testing of soil - Part 7: Unconfined
compression test on fine-grained soil (ISO/TS 17892-7:2004)
Geotechnische Erkundung und Untersuchung - Laborversuche an Bodenproben - Teil 7:
Einaxialer Druckversuch an feinkörnigen Böden (ISO/TS 17892-7:2004)
Reconnaissance et essais géotechniques - Essais de laboratoire sur les sols - Partie 7:
Essai de compression uniaxiale sur des sols fins (ISO/TS 17892-7:2004)
Ta slovenski standard je istoveten z: CEN ISO/TS 17892-7:2004
ICS:
13.080.20 Fizikalne lastnosti tal Physical properties of soils
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CEN ISO/TS 17892-7
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
October 2004
ICS 13.080.20; 93.020
English version
Geotechnical investigation and testing - Laboratory testing of
soil - Part 7: Unconfined compression test on fine-grained soil
(ISO/TS 17892-7:2004)
Reconnaissance et essais géotechniques - Essais de sol Geotechnische Erkundung und Untersuchung -
au laboratoire - Partie 7 : Essai de compression simple sur Laborversuche an Bodenproben - Teil 7: Einaxialer
sols cohérents (ISO/TS 17892-7:2004) Druckversuch an feinkörnigen Böden (ISO/TS 17892-
7:2004)
This Technical Specification (CEN/TS) was approved by CEN on 2 February 2004 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN ISO/TS 17892-7:2004: E
worldwide for CEN national Members.

Contents
page
Foreword.3
1 Scope .5
2 Normative references .5
3 Terms and definitions .5
4 Equipment .6
5 Test procedure.8
6 Test results.10
7 Test report .11
Bibliography .12

Figures
Figure 1 — Schematic drawing of a loading machine for performing unconfined compression tests.7

Foreword
This document (CEN ISO/TS 17892-7:2004) has been prepared by Technical Committee CEN/TC 341
“Geotechnical investigation and testing”, the secretariat of which is held by DIN, in collaboration with Technical
Committee ISO/TC 182 “Geotechnics”.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Cyprus, Czech Republic, Denmark,
Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
CEN ISO/TS 17892 consists of the following parts, under the general title Geotechnical investigation and testing —
Laboratory testing of soil:
 Part 1: Determination of water content.
 Part 2: Determination of density of fine-grained soil.
 Part 3: Determination of particle density - Pycnometer method.
 Part 4: Determination of particle size distribution.
 Part 5: Incremental loading oedometer test.
 Part 6: Fall cone test.
 Part 7: Unconfined compression test on fine-grained soils.
 Part 8: Unconsolidated undrained triaxial test.
 Part 9: Consolidated triaxial compression tests.
 Part 10: Direct shear tests.
 Part 11: Permeability tests.
 Part 12: Determination of Atterberg limits.
Introduction
This document covers areas in the international field of geotechnical engineering never previously standardised. It
is intended that this document presents broad good practice throughout the world and significant differences with
national documents is not anticipated. It is based on international practice (see [1]).
1 Scope
This document covers the determination of an approximate value of the unconfined compressive strength for a
square or cylindrical water-saturated homogeneous specimen of undisturbed or remoulded cohesive soil of
sufficiently low permeability to keep itself undrained during the time it takes to perform the test within the scope of
geotechnical investigations according to prEN 1997-1 and -2.
The unconfined compressive strength of cohesive soils is a measure of the apparent cohesion. A cohesive soil
behaves as if it is truly cohesive, e.g. clay and clayey soils, but most soils in this group behave cohesively due to
negative pore pressure and friction and not due to actual cohesion.
This test method is useful to derive the undrained shear strength of soil. It should however be noted that no
provisions are taken to prevent drainage. The derived value for undrained shear strength is therefore only valid for
soils of low permeability, which behave sufficiently undrained during testing.
The method is not appropriate for fissured or varved clays or silts or peats.
2 Normative references
The following referenced documents are indispensable for the application 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.
prEN 1997-1, Eurocode 7: Geotechnical design - Part 1: General rules
prEN 1997-2, Eurocode 7: Geotechnical design - Part 2: Design assisted by laboratory testing
CEN ISO/TS 17892-1, Geotechnical investigation and testing — Laboratory testing of soil — Part 1: Determination
of water content (ISO/TS 17892-1:2004).
CEN ISO/TS 17892-2, Geotechnical investigation and testing — Laboratory testing of soil — Part 2: Determination
of bulk density (ISO/TS 17892-2:2004).
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
unconfined compressive strength
q
u
maximum vertical stress an unconfined specimen can sustain or the vertical stress at 15 % vertical strain,
whichever occurs first during the performance of the test
3.2
undrained shear strength
c
u
undrained shear strength is equal to one half of the unconfined compressive strength
3.3
undisturbed sample
normally sample of quality class 1 according to prEN 1997-2
4 Equipment
4.1 Loading machine
4.1.1 General
A loading machine for performance of unconfined compression tests (see Figure 1) normally consists of the
following main parts:
a) Top and bottom platen between which the soil specimen is placed;
b) load frame with a drive unit to compress the soil specimen (loading press);
c) load measuring device to measure the force applied to the soil specimen;
d) compression measuring device to measure the axial compression of the specimen.
4.1.2 Loading press
4.1.2.1 The loading press shall have sufficient capacity to load the soil specimen to failure (see 4.1.4.3).
4.1.2.2 The top and the bottom platen shall be designed such that their deformations are negligible compared
to the deformations of the soil specimen, and their diameter shall be so large that no part of the soil specimen
projects beyond them.
4.1.2.3 Both platens may be prevented from tilting as shown in Figure 1, or one platen, usually the top platen,
may be allowed to tilt, but neither of the platens shall be allowed to move horizontally.
Key
1 load frame
2 load measuring device
3 top platen
4 bottom platen
5 soil specimen
6 drive unit
7 axial compression measuring device
Figure 1 — Schematic drawing of a loading machine for performing unconfined compression tests
4.1.2.4 The drive unit shall move one of the platens with a constant speed, called the platen rate, which shal
...