CEN ISO/TS 17892-10:2004

SLOVENSKI STANDARD
01-december-2004
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Geotechnical investigation and testing - Laboratory testing of soil - Part 10: Direct shear
tests (ISO/TS 17892-10:2004)
Geotechnische Erkundung und Untersuchung - Laborversuche an Bodenproben - Teil
10: Direkte Scherversuche (ISO/TS 17892-10:2004)
Reconnaissance et essais géotechniques - Essais de laboratoire sur les sols - Partie 10:
Essais de cisaillement direct (ISO/TS 17892-10:2004)
Ta slovenski standard je istoveten z: CEN ISO/TS 17892-10:2004
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 17892-10
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
October 2004
ICS 13.080.20; 93.020
English version
Geotechnical investigation and testing - Laboratory testing of
soil - Part 10: Direct shear tests (ISO/TS 17892-10:2004)
Reconnaissance et essais géotechniques - Essais de sol Geotechnische Erkundung und Untersuchung -
au laboratoire - Partie 10: Essai de cisaillement direct Laborversuche an Bodenproben - Teil 10: Direkte
(ISO/TS 17892-10:2004) Scherversuche (ISO/TS 17892-10:2004)
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 17892-10:2004: 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 Specimen .9
6 Test procedure.10
7 Test results.12
8 Test report .14
Bibliography .16

Figures
Figure 1 — Schematic drawing of a conventional and a parallel controlled shearbox.7
Figure 2 — Example of a ring shear apparatus .8
Figure 3 — Example of time-settlement-curve to determine the time for primary consolidation .10
Figure 4 — Determination of the friction angle φ' as a function of the void ratio e .14

Foreword
This document (CEN ISO/TS 17892-10:2004) 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 of 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 specifies laboratory test methods to establish the effective shear strength parameter for soils within
the scope of the geotechnical investigations according to prEN 1997-1 and -2.
The test method consists of placing the test specimen in the direct shear device, applying a pre-determined normal
stress, providing for draining (and wetting if required) of the test specimen, or both, consolidating the specimen
under normal stress, unlocking the frames that hold the specimen, and displacing one frame horizontally with
respect to the other at a constant rate of shear-deformation and measuring the shearing force, and horizontal
displacements as the specimen is sheared. Shearing is applied slowly enough to allow excess pore pressures to
dissipate by drainage so that effective stresses are equal to total stresses.
Direct shear tests are used in earthworks and foundation engineering for the determination of the effective shear
strength of soils.
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: Ground investigation and 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)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
direct shear test
test whereby a square or circular prism or annular specimen of soil is laterally restrained and sheared along a
mechanically induced horizontal plane while subjected to a pressure applied normal to that plane
3.2
shearbox test
direct shear test whereby a specimen is placed in a rigid container (shearbox) which is square or circular and
divided horizontally into two halves.
NOTE Shearing is applied by displacing the two halves of the shearbox relative to each other (see Figure 1)
3.3
ring shear test
direct shear test whereby an annular specimen is subjected to rotational shear while subjected to vertical stress
(see Figure 2)
3.4
friction angle
ϕ'
angle of friction, as determined from effective stresses
3.5
cohesion
c'
cohesion intercept, as determined from effective stresses
4 Equipment
4.1 Shearbox
4.1.1 The shearbox shall be square or circular in plan and divided horizontally into two rigid halves which prevent
horizontal deformation of the specimen.
4.1.2 Arrangements shall be provided for locking the two halves of the shearbox securely together while the
specimen is being placed, and for lifting the upper half of the box from the lower half by a small controlled vertical
displacement without tilt, after applying vertical load to the specimen.
4.1.3 The arrangement shall be such that when released one half of the shearbox shall be able to move exactly
parallel to the other half.
4.1.4 The loading cap shall be 0,5 mm smaller in plan than the internal dimensions of the shearbox and be rigid
enough to transmit the vertical load uniformly to the specimen.
4.1.5 The loading cap should preferably be guided by a bearing to prevent tilting during shear.
Key
a conventional device
b parallel controlled device
1 loading pad
2 porous plate
3 soil specimen
4 force transducer
Figure 1 — Schematic drawing of a conventional and a parallel controlled shearbox
4.1.6 During testing, the shear box shall be placed in an outer container (the carriage), such that the test
specimen is submerged under water during the test.
4.1.7 The carriage shall be supported on the bed of the machine by a low-friction bearing which allows
movement in the longitudinal direction only.
4.1.8 To achieve a uniform distribution of the shear stresses over the plan of the specimen rough porous filter
plates shall cover the upper and the lower surface of the specimen. The porous plates shall be of a material which
does not react chemically with the pore water or the soil. Their porosity shall prevent intrusions of soil into the
pores, but shall allow free drainage of water throughout the test. Therefore the permeability of the porous platens
shall be at least 10 times the permeability of the specimen.
4.1.9 Typical arrangements for a conventional and a parallel controlled shearbox are shown in Figure 1.
NOTE A parallel controlled shear box allows a correct simulation of in-situ shearing when shear planes occur.
Investigations show that with cohesive soils the friction angle φ is up to 4° smaller and with non-cohesive soils it is up to 6°
higher in a parallel controlled shearbox than in a conventional apparatus.
4.2 Ring shear apparatus
4.2.1 The apparatus shall be constructed such that shearing forces are purely torsional.
4.2.2 The soil container rings shall be of sufficient stiffness to prevent radial deformation of the specimen.
4.2.3 The soil container rings shall be integrated in a water bath which allows the specimen to be submerged
during the test.
4.2.4 The upper and lower rings shall be fitted with porous platens having the same properties as those in the
shear box (see 4.1.8).
4.2.5 The ring shear apparatus shall contain a device for application of vertical (normal) stresses.
4.2.6 A typical arrangement for a ring shear apparatus is shown in Figure 2.
Key
1 specimen
2 filter stones
3 upper circular frame (fixed)
4 lower circular frame (rotating)
5 bearing to lift upper circular frame
6 loading lever for normal stress
7 loading and measurement of torque
Figure 2 — Example of a ring shear apparatus
4.3 Loading system
4.3.1 The normal load shall be kept constant during shearing.
4.3.2 Shearing must be achieved by continuous horizontal or torsional displacement.
4.3.3 If only the peak shear stress is to be determined shearing can also be done by constant increase of the
shear load.
4.3.4 Shearbox equipment shall allow a minimum horizontal displacement of 20 % of the length or diameter of
the specimen.
4.3.5 Ring shear equipment shall allow a travel by torsion of 30 mm.
4.4 Measurement of forces and displacements
4.4.1 Force
The vertical force shall be measured with an accuracy of 3 %, or within 2,5 N, whichever is the gr
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