🏗️ Determination of the effective shear strength of soil under consolidated drained conditions — specimen in a rigid square or circular box (width or diameter at least 50 mm, height at least 20 mm or 6 largest particles, ratio at least 2,5) or in a Type A or B ring shear apparatus, consolidation under vertical stress and shearing at a constant rate slow enough for excess pore pressure to dissipate; usually at least three specimens at different stresses, PN-EN ISO 17892-10

Construction PN-EN ISO 17892-10

Overview

WHAT THE STANDARD COVERS. Scope from the PKN catalogue card of PN-EN ISO 17892-10:2019-01 (English version; scope in Polish on the card), in full (our translation of the Polish card text): “This document specifies two laboratory test methods for determining the shear strength of soils under consolidated and fully drained conditions using a direct shear apparatus or a ring shear apparatus. This document applies to laboratory tests for determining the shear strength of soils subjected to direct shear as part of geotechnical investigation. The tests in this document are carried out on undisturbed, re-compacted and reconstituted specimens. The test procedure defines the requirements for determining the shear strength of a soil specimen tested under a constant vertical (normal) stress. In principle, to determine the shear strength of a given soil in accordance with Annex B, three or more similar specimens sheared at different vertical stresses are tested. This document does not specify special test procedures such as staged loading or pre-shearing, or tests of the shear strength of the interface between soil and other materials. NOTE This document meets the requirements for determining the shear strength of soils in direct shear tests within geotechnical investigations in accordance with EN 1997-1 and EN 1997-2.” We read the text of the standard in the preview of ISO 17892-10:2018 from the cover to clause 5.2.2.1 and Figure 2 (page 6); we do not have specimen preparation, the test procedure, calculations or Annexes A and B.

ACCORDING TO THE TEXT OF ISO 17892-10:2018 (foreword, introduction, Clauses 1–5.2.2.1). The standard was prepared by CEN/TC 341 together with ISO/TC 182 (Vienna Agreement). The first edition replaces ISO/TS 17892-10:2004 with Technical Corrigendum Cor 1:2006; changes: general revision of text and figures and addition of specimen preparation procedures; two types of ring shear apparatus — Type A, in which failure occurs at the depth defined by the split specimen container, and Type B, in which the apparatus does not define the location of the failure surface; Annex A on calibration, maintenance and checks; Annex B with additional calculations of effective strength parameters. Introduction: the tests had not previously been standardized internationally; two methods under consolidated drained conditions — the shearbox usually for peak and the ring shear apparatus usually for residual parameters of fine-grained soils (the reverse is also possible); the specimen is placed in the apparatus, a predetermined vertical stress is applied, drainage (and wetting if required) is provided, the specimen is consolidated and sheared by displacing one part horizontally relative to the other at a constant rate; the shear force and horizontal and vertical displacements are measured; shearing must be slow enough for excess pore pressure to dissipate by drainage so that effective stresses equal total stresses. Scope (Clause 1, as on the card). References: ISO 17892-1 (water content), ISO 14688-1 (identification and description of soil), ISO 386 (thermometers). Definitions (Clause 3): direct shear test — specimen laterally restrained and sheared along a mechanically induced horizontal plane under vertical stress; shearbox test — rigid square or circular container, linear displacement of one half; ring shear test — annular specimen, rotation of one half; failure — condition at which the peak horizontal shear stress is reached or, if there is no peak, a specified deformation criterion; primary consolidation. Symbols (Clause 4) include φ′, φ′R, c′, τR, time to failure tf, maximum allowable displacement rate vmax and torque Mt. Apparatus (5.1): regular calibration, maintenance and checks according to Annex A. Shearbox (5.2.1): Figure 1 — vertical force, loading cap, porous discs or shear friction plates, upper and lower part of the box, specimen, outer container (carriage), device applying a constant rate of horizontal displacement, measurement of horizontal displacement, horizontal force and vertical displacement, gap between the parts of the box; frame, carriage, box and components of corrosion-resistant, rigid materials; the carriage should allow testing under water; a low-friction bearing allows only horizontal movement; square or circular box, divided horizontally into two rigid halves that can be locked together (smooth internal surface) and separated vertically before shearing without tilt; a square box should take a specimen at least 50 mm wide, a circular one at least 50 mm in diameter; initial height at least 20 mm or 6 times the largest particle diameter (whichever is larger); ratio of width or diameter to height not less than 2,5; porous discs or friction plates let water through without intrusion of particles, are plane, corrosion-resistant, practically incompressible, rough enough without local stress concentrations and smaller than the inside of the box; loading cap smaller than the inside (it can tilt without jamming), with grooves or perforations for drainage. Ring shear apparatus (5.2.2.1): purely rotational shear forces; Figure 2 — Type A with a split container (lower and upper circular frame, loading ring with drainage opening, measurement of torque Mt, water bath, measurement of vertical displacement); Figure 3 — Type B with a solid container; this is where the part we read ends.

STATUS (cards as of 02.10.2026). The card of PN-EN ISO 17892-10:2019-01 (English version, published 28-01-2019, 36 pages, price group R) has no “Withdrawn” header: Construction and Building Structures Sector, KT 254 Geotechnics, ICS 13.080.20, 93.020, “Introduces: EN ISO 17892-10:2018 [IDT], ISO 17892-10:2018 [IDT]”; the card has no “Replaces” field. PKN-CEN ISO/TS 17892-10:2009 (Polish version, “Geotechnical investigation and testing — Laboratory testing of soil — Part 10: Direct shear test”, published 11-08-2009, 17 pages; introduced CEN ISO/TS 17892-10:2004 with AC:2005 and ISO/TS 17892-10:2004) — “Withdrawal date: 22-01-2019”.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17.09.2026, read on 02.10.2026). The number 17892-10 appears in 12 records at 8 laboratories: AB 298, AB 962, AB 1299, AB 1416, AB 1770, AB 1778, AB 1806, AB 1914. In the current scopes on the PCA website (read on 02.10.2026, issues from 24.09.2024 to 17.07.2026) the number appears at all 8: “PN-EN ISO 17892-10:2019-01” at seven (AB 1416 with the note “E”, AB 1806 with an asterisk), while AB 1299 has the withdrawn specification “PKN-CEN ISO/TS 17892-10:2009” (angle of friction of the 0–5 mm fraction in a shearbox). AB 1770 lists both apparatus — shearbox (0–10 kN) and ring shear (0–1 kN) — in two places of its scope. No row is set in bold italics. The “Laboratories” tab searches for entries BEGINNING WITH “PN-EN ISO 17892-10” and shows 7 laboratories (without AB 1299, whose entry begins with “PKN-CEN ISO/TS 17892-10”) — checked with a query of the tab on the production server labcoda.pl on 02.10.2026.

WHAT THE LABORATORIES TEST (items in the PCA scopes). Soils (AB 298 also aggregates) — “shear strength”, “cohesion and angle of internal friction in a direct shear apparatus” (AB 298), “angle of friction” and “cohesion” (AB 1778), “shear stresses, force range 0–800 kPa” (AB 1806), “direct shear test — shearbox apparatus” (AB 962, AB 1416, AB 1914); usually next to other parts of PN-EN ISO 17892 (particle size distribution, oedometer, triaxial compression) and Proctor tests.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. Rate: too fast shearing does not allow the pore pressure to dissipate — the result is then not an effective (CD) strength, although the apparatus gives numbers. Dimensions: specimen height at least 20 mm or 6 largest particles and a width-to-height ratio of at least 2,5 — a coarse-grained soil in a 50 mm box often does not meet these conditions. Number of specimens: one specimen gives one point (resistance at one stress); the parameters φ′ and c′ usually require at least three specimens at different stresses. Kind of parameter: the shearbox usually gives peak values, the ring shear apparatus residual ones; they should not be mixed. Ring shear apparatus: Type A forces the depth of shearing, Type B does not — these are two different arrangements, not substitutes. Specification: PKN-CEN ISO/TS 17892-10:2009 has been withdrawn since 22-01-2019, and the 2018 standard added specimen preparation procedures, Annex A (calibration) and a second type of ring shear apparatus.

WHAT WE DO NOT GIVE. We do not have the clauses on specimen preparation, the consolidation and shearing procedure, calculation of the shearing rate (tf, vmax), the calculations or Annexes A and B — so we do not give formulae, rates or criteria for ending shearing.

Method principle

A soil specimen in a rigid box (or ring) is consolidated under vertical stress and then sheared by displacing (or rotating) one part relative to the other at a constant, sufficiently low rate for pore pressure to dissipate; effective strength parameters are determined from the resistance of several specimens at different stresses.

Applications

• Soils in geotechnical investigation (EN 1997-1, EN 1997-2) — 8 laboratories in the PCA scopes
• Angle of internal friction and cohesion of soils and fine aggregates (shearbox)
• Residual strength of fine-grained soils (ring shear apparatus, AB 1770)

Key parameters

Standard

Standard number

PN-EN ISO 17892-10:2019-01 (wersja angielska; EN ISO 17892-10:2018 IDT, ISO 17892-10:2018 IDT)

Title (PL)

Rozpoznanie i badania geotechniczne — Badania laboratoryjne gruntów — Część 10: Badania w aparacie bezpośredniego ścinania

Title (EN)

Geotechnical investigation and testing — Laboratory testing of soil — Part 10: Direct shear tests

Step-by-step procedure

1. Specimen

   Undisturbed, remoulded, re-compacted or reconstituted soil; dimensions according to 5.2.1.5; usually three or more similar specimens. PN-EN ISO 17892-10:2019-01 current (cards as of 02.10.2026).

2. Set-up

   Specimen between porous discs in the locked box (or in the ring), loading cap, set vertical stress.

3. Consolidation

   Drainage (and wetting if required) and consolidation under the vertical stress.

4. Shearing

   Separation of the halves without tilt and displacement (rotation) of one part at a constant, sufficiently low rate; measurement of shear force and horizontal and vertical displacements.

5. Parameters

   Shear resistance of each specimen at its stress; from several specimens — effective strength parameters according to Annex B (peak or residual).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The part of the standard we read contains no safety warnings; loads and drives of the apparatus — care when placing weights, work with water near electrical equipment
• TECHNICAL NOTE: the result is an effective strength only if shearing is slow enough for pore pressure to dissipate; the parameters require several specimens at different stresses

Frequently asked questions