SIST-TS CEN ISO/TS 17892-11:2004
(Main)Geotechnical investigation and testing - Laboratory testing of soil - Part 11: Determination of permeability by constant and falling head (ISO/TS 17892-11:2004)
Geotechnical investigation and testing - Laboratory testing of soil - Part 11: Determination of permeability by constant and falling head (ISO/TS 17892-11:2004)
This document is intended for use in earthworks and foundation engineering. It specifies laboratory test methods to establish the coefficient of permeability of water through water saturated soils. In the proposed laboratory tests soil specimens are subjected to a flow of water passing through the specimen. The water pressure conditions and volume of water passing through the specimens are measured for evaluation of the permeability.
The results obtained serve to calculate groundwater flow and to assess the permeability of man made impervious layers and filter layers.
Geotechnische Erkundung und Untersuchung - Laborversuche an Bodenproben - Teil 11: Bestimmung der Durchlässigkeit mit konstanter und fallender Druckhöhe (ISO/TS 17892-11:2004)
Reconnaissance et essais géotechniques - Essais de laboratoire sur les sols - Partie 11: Détermination de perméabilité a charge constante et a charge variable décroissante (ISO/TS 17892-11:2004)
L'ISO 17892-11:2004 est destinée à être utilisé dans le domaine des techniques de terrassement et de fondations. Il spécifie les méthodes d'essai en laboratoire permettant de déterminer le coefficient de perméabilité à l'eau des sols saturés. Dans les essais décrits, les éprouvettes de sol sont soumises à un écoulement d'eau. La pression et le volume d'eau traversant les éprouvettes sont mesurés afin d'évaluer la perméabilité.
Les résultats obtenus servent à calculer l'écoulement souterrain et à évaluer la perméabilité de couches filtrantes et de couches imperméables anthropiques.
Geotehnično preiskovanje in preskušanje – Laboratorijsko preskušanje zemljin – 11. del: Ugotavljanje prepustnosti s konstantnim in spremenljivim hidravličnim padcem (ISO/TS 17892-11:2004)
Ta dokument se uporablja pri zemeljskih delih in temeljenju. Določa laboratorijske preskusne metode za ugotavljanje koeficienta prepustnosti vode skozi z vodo zasičene zemljine. V predlaganih laboratorijskih preskusih skozi vzorce zemljin prehaja tok vode. Prepustnost se vrednoti z merjenjem tlaka in volumna vode, ki prehaja skozi vzorec. Dobljeni rezultati se uporabljajo za izračun pretoka podtalnice in za ocenjevanje prepustnosti umetnih neprepustnih plasti in filtrirnih plasti.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST-TS CEN ISO/TS 17892-11:2004
01-december-2004
*HRWHKQLþQRSUHLVNRYDQMHLQSUHVNXãDQMH±/DERUDWRULMVNRSUHVNXãDQMH]HPOMLQ±
GHO 8JRWDYOMDQMHSUHSXVWQRVWLVNRQVWDQWQLPLQVSUHPHQOMLYLPKLGUDYOLþQLP
SDGFHP ,6276
Geotechnical investigation and testing - Laboratory testing of soil - Part 11:
Determination of permeability by constant and falling head (ISO/TS 17892-11:2004)
Geotechnische Erkundung und Untersuchung - Laborversuche an Bodenproben - Teil
11: Bestimmung der Durchlässigkeit mit konstanter und fallender Druckhöhe (ISO/TS
17892-11:2004)
Reconnaissance et essais géotechniques - Essais de laboratoire sur les sols - Partie 11:
Détermination de perméabilité a charge constante et a charge variable décroissante
(ISO/TS 17892-11:2004)
Ta slovenski standard je istoveten z: CEN ISO/TS 17892-11:2004
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
SIST-TS CEN ISO/TS 17892-11:2004 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST-TS CEN ISO/TS 17892-11:2004
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SIST-TS CEN ISO/TS 17892-11:2004
TECHNICAL SPECIFICATION
CEN ISO/TS 17892-11
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
October 2004
ICS 13.080.20; 93.020
English version
Geotechnical investigation and testing - Laboratory testing of
soil - Part 11: Determination of permeability by constant and
falling head (ISO/TS 17892-11:2004)
Reconnaissance et essais géotechniques - Essais de sol Geotechnische Erkundung und Untersuchung -
au laboratoire - Partie 11: Détermination de la perméabilité Laborversuche an Bodenproben - Teil 11: Bestimmung der
au perméamètre à charge constante ou variable (ISO/TS Durchlässigkeit mit konstanter und fallender Druckhöhe
17892-11:2004) (ISO/TS 17892-11:2004)
This Technical Specification (CEN/TS) was approved by CEN on 2 December 2003 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 17892-11:2004: E
worldwide for CEN national Members.
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Contents Page
Foreword.3
1 Scope .5
2 Normative references .5
3 Terms and definitions .5
4 Test procedure.6
4.1 General requirements.6
4.1.1 Grading, particle structure and volume .6
4.1.2 Properties of water .6
4.1.3 Degree of saturation.6
4.2 Falling head .12
4.2.1 Apparatus .12
4.2.2 Test arrangement.13
4.2.3 Soil type and specimen dimensions.13
4.3 Constant head test in the permeameter .14
4.3.1 Apparatus .14
4.3.2 Test arrangement.14
4.3.3 Soil type and specimen dimensions.14
4.4 Constant head testing in the triaxial cell.15
4.4.1 Apparatus (see Figure 2).15
4.4.2 Test arrangement.16
4.4.3 Preparation of apparatus .16
5 Test results.17
5.1 Falling head .17
5.2 Constant head.18
5.3 Permeability in the triaxial cell .18
Bibliography .20
Figures
Figure 1 — Water flow in a soil specimen.6
Figure 2 — Example for test arrangement for triaxial cell test .7
Figure 3 — Example for a test arrangement for constant head permeameter test.9
Figure 4 — Example for a test arrangement for compression permeameter test.10
Figure 5 — Apparatus for enclosing a specimen in a rubber membrane .11
Tables
Table 1 — Back pressure as function of initial saturation .7
Table 2 — Correction factor αα to allow for the viscosity of water .8
αα
Table 3 — Classes of permeability tests .12
Table 4 — Example for test arrangement as a function of soil type .12
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Foreword
This document (CEN ISO/TS 17892-11:2004) 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 grain soils
Part 8: Unconsolidated undrained triaxial test
Part 9: Consolidated triaxial compression tests on water saturated soils
Part 10: Direct shear tests
Part 11: Determination of permeability by constant and falling head
Part 12: Determination of the Atterberg limits
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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]).
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1 Scope
This document is intended for use in earthworks and foundation engineering. It specifies laboratory test methods to
establish the coefficient of permeability of water through water-saturated soils. In the proposed laboratory tests soil
specimens are subjected to a flow of water passing through the specimen. The water pressure conditions and
volume of water passing through the specimens are measured for evaluation of the permeability.
The results obtained serve to calculate groundwater flow and to assess the permeability of man-made impervious
layers and filter layers.
2 Normative references
The following referenced document is 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 1997-2, Eurocode 7 - Geotechnical design — Part 2: Ground investigation and testing.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
flow rate
Q
quantity of water passing through a specimen per unit time, t
3.2
discharge velocity
v
rate of flow of water per unit area of soil (including particles and voids) normal to the direction of flow
3.3
hydraulic gradient
i
ratio of the difference in total head of water (head loss), h, between two gland points, to the length of the flow path,
l (distance between the gland points measured in the direction of flow, see Figure 1)
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Key
1 Standpipe head
2 Standpipe
3 Filter block
4 Filter block
5 Specimen
Figure 1 — Water flow in a soil specimen
3.4
undisturbed sample
normally a sample of quality class 1 or at least 2 according to prEN 1997-2
3.5
coefficient of permeability
k
in accordance with Darcy's law for laminar flow, the coefficient of permeability of a water-saturated soil, k, is the
ratio of the discharge velocity, v, to the hydraulic gradient, i
NOTE For partly saturated soil, the coefficient of permeability is always smaller than for fully water-saturated soil due to
turbulence caused by air voids and non-function of .capillary action.
4 Test procedure
4.1 General requirements
4.1.1 Grading, particle structure and volume
Grading and particle structure shall not alter while measuring the permeability. Consolidation and swelling should
substantially be completed before the measurements are done.
In clay swelling and consolidation cannot completely be avoided unless provisions are made to prevent it.
Therefore, the height of the specimen should be locked or the load regulated to prevent changes in height. The
height of the specimen should be recorded and any significant change in height should be accounted for, both in
terms of expelled water and in change of seepage path.
4.1.2 Properties of water
The water used for testing shall not wash out constituents of the specimen, deposit any dissolved or suspended
matter in it or alterthe colloidal state of the soil.
As far as possible, water similar in type to the pore water shall be used, de-aired tap water generally being
adequate. Where necessary (e.g. where marine sediments are to be tested), the water shall be treated or obtained
from a given source so that the natural conditions can be reliably reproduced.
4.1.3 Degree of saturation
4.1.3.1 The specimen shall remain saturated during the measurement of the permeability.
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4.1.3.2 Saturation of the specimen can be achieved by applying a back pressure u (as specified in Table 1),
0
which is produced by subjecting the pore water in the specimen to a hydrostatic pressure which shall be
maintained throughout the test. This may be accomplished using the test arrangement shown in Figure 2.
Table 1 — Back pressure as function of initial saturation
Initial saturation Back pressure
S u
r 0
2
% kN/m
100 0
95 300
90 600
85 900
Key
9 Pressure gauge
1 Top plate
10 Burette to determine the quantity of inflowing water
2 Cell top with spiral groove
11 Vessel containing pressurized de-aired water
3 Filter block with k greater than or equal to ten times that of
12 Supply of de-aired water
the specimen
13 Inlet for cell water and cell pressure, σ
3
4 Specimen
14 Valve
5 Rubber membrane with O-rings
15 Piston for applying anisotropic load to the specimen
6 Pedestal
l Specimen height (= length of seepage path)
7 Glass tube with vent opening less than 1 mm in diameter 0
8 Graduated glass cylinder or volume change sensor p Pressure to produce hydraulic gradient
In tests with back pressure, the pressure in the vent opening (7) should be raised to correspond to the back-pressure u and the
0
pressure p raised to p + u .
0
Figure 2 — Example for test arrangement for triaxial cell test
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At full saturation, the quantities of water entering and leaving a specimen shall be equal, with constant pressure
and constant hydraulic gradient being assumed.
Disturbed specimens are normally not fully saturated with water, the same applying to specimens in which the pore
water pressure dropped as the specimen was taken, thus releasing dissolved gas. Air dissolved in the water
passing through the specimen may be retained in the specimen and thus reduce the latter's permeability.
There are also other methods to saturate specimens. It can be done e.g. by flushing the specimen with water or by
replacing the air in the dry specimen by CO before filling the specimen with water. Bubbles of CO can more easily
2 2
be solved in water.
4.1.4 Hydraulic gradient
For testing purposes, the hydraulic gradient may be selected to satisfy practical considerations as long as the flow
characteristics given by the gradient complies with Darcy's law. In case of doubt whether the test conditions comply
with Darcy's law the hydraulic gradient has to be varied to check it. Where the flow is not linear, the hydraulic
gradient in the laboratory shall approximate that in the field.
NOTE The flow behaviour of coarse-grained soil deviates from laminar flow as described by Darcy's law, if the hydraulic
gradient exceeds a certain level, i.e. the discharge velocity increases non-linearly with increasing hydraulic gradient due to the
influence of inertial forces. For fine-grained soil the discharge velocity decreases non-linearly with decreasing hydraulic gradient
when passing a certain lower level.
4.1.5 Temperature
4.1.5.1 Testing shall be carried out at approximately constant ambient temperature (± 2 °C), with which the
temperature of the specimen and water shall be in equilibrium. The temperature shall be measured and recorded.
4.1.5.2 To obtain reproducible results, the value of k as determined in the test shall be converted to a
reference temperature of 10 °C using the following empirical equation (1) from Poiseuille:
k = α × k (1)
T
10
1,359
α = (2)
2
1+ 0,0337 ×T + 0,00022×T
where
T is the water temperature (°C) throughout the test;
k is the coefficient of permeability at ambient temperature (m/s);
T
α is a correction factor, to be calculated or taken from Table 2. For intermediate values linear interpolation is
allowed.
A reference temperature of 10 °C equals the average temperature of groundwater. A different temperature may be
used where required.
Table 2 — Correction factor α to allow for the viscosity of water
Temperature T
5 10 15 20 25
[°C]
Correction factor
1,158 1,000 0,874 0,771 0,686
α [–]
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4.1.6 Specimen dimensions
4.1.6.1 Specimen diameter and height shall be selected so as to prevent any inhomogeneities influencing the
test results.
4.1.6.2 The ratio of maximum particle size to specimen diameter or length shall be not less than 1 : 5 for
non-uniform and 1 : 10 for uniform soils.
4.1.6.3 For cohesive (fine-grained) soil, the cross-sectional area of the specimen A shall be not less than
2 2
1000 mm and for coarse-grained soil, not less than 2000 mm , unless the test equipment requires the use of
larger specimens (see 4.4.4).
4.1.7 Measurement of standpipe heads
4.1.7.1 For permeable to highly permeable soil specimens, the difference in head shall not be measured
between the specimen ends but only across the length of that part of the specimen through which the water is
flowing (see Figure 3), in order to prevent any loss of head and to prevent the result being affected by interference
effects at the specimen ends.
Key
1 Inlet for de-aired water
9 Graduated scale
2 Pinch cock or ball valve
10 Graduated cylinder
3 Inlet reservoir
11 Cell
4 Outlet reservoir
h Difference in piezometric heads
5 Filter
h Difference in head in inlet and outlet reservoirs
w
6 Perforated plate with wire gauze
l Length of seepage path
7 Specimen
l Specimen height
8 Piezometric tubes 0
Figure 3 — Example for a test arrangement for constant head permeameter test
4.1.7.2 Standpipes (piezometric tubes) shall have an internal diameter of 3 mm to 4 mm and be located at a
minimum of 15 mm from the top and bottom ends of the specimen. The end of the tube entering the specimen shall
be protected by a wire gauze against blockage. In the case of soil with low permeability, the loss of head between
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the standpipes and cell is small enough to be ignored so that the difference in head between inlet and outlet may
be regarded as being equal to the difference in head across the specimen.
4.1.8 Measurement of water flow
4.1.8.1 The quantity of water flowing through the specimen shall be measured at steady-state flow conditions.
4.1.8.2 In constant head tests with large quantities of water passing through the specimen, the overflow at the
outlet end shall be measured.
4.1.8.3 Where the quantities of water passing through the specimen are small, measurement shall be carried
out using piezometric tubes (see Figure 4) or capillary tubes, due consideration being given to the possibility of
evaporation falsifying the results. This may be avoided by increasing the hydraulic gradient, provided this is not
inconsistent with the other conditions described in 4.1.4.
Key
1 Inlet for de-aired water
2 Detachable piezometric tube of cross-
sectional area a
3 Three-way cock
4 Rubber seal
5 Filter blocks
6 Specimen holder
7 Specimen with height l
0
8 Top plate
9 Device to apply vertical load, with
compression gauge
10 Container (with overflow to produce
constant head)
h Water head at start of measurement
1
h Water head at time t
2
Figure 4 — Example for a test arrangement for compression permeameter test
4.1.8.4 In falling head tests, the volume of water passing through the specimen is equal to the internal volume
of the standpipe as defined by the difference in level of two consecutive readings.
NOTE The water flow can be regarded as steady if, at a constant head, the quantity of water entering the specimen and that
leaving it per unit time remains constant.
4.1.9 Prevention of bypass seepage
4.1.9.1 Bypass seepage due to small stones and other foreign matter embedded in specimens and cavities
between the specimen and the wall of the cell or test mould shall be prevented as it suggests a higher permeability
than is in fact is the case. Any such channels and cavities shall be filled, for example with material from the sample,
bentonite or silicone grease.
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4.1.9.2 If seepage along the wall cannot be prevented due to the presence of coarse constituents in coarse-
grained material, it is recommended that the core cutter be lined with a solid material having a low melting point
(e.g. paraffin wax) or before the specimen is taken, so that the gap between specimen and cutter wall is sealed by
heating once the specimen has been taken. The sealant shall not penetrate into the specimen. This is to be
checked after the test.
In the case of specimens of cohesive (fine-grained) material, seepage can be prevented by placing them in a
mould with an internal diameter a few millimetres larger than the specimen diameter, the gap being filled by pouring
a sealing compound. An apparatus as shown in Figure 5 may be used to introduce such specimens into a mould
lined with a tubular latex membrane. While inserting the specimen, the membrane shall be held in place by
exhausting the mould. The internal diameter of the mould shall be larger than that of the core cutter by more than
twice the thickness of the membrane. In the test, the membrane shall be pressed against the specimen with a
pressure 20 % above the maximum pore water pressure, this pressure being applied via water since latex is not
airtight. Silicone grease between two membranes may also be used to prevent air passing through the membrane.
Test arrangements as shown in Figure 2 may be used to prevent undue seepage along the walls where cohesive
(fine-grained) material is to be tested.
Key
1 Jack
2 Baseplate
3 Piston
4 Centring tube
5 Tie rods
6 Core cutter with sample
7 Tubular rubber membrane
8 Intermediate collar
9 Mould for permeability test
10 Pressurizing/depressurizing nozzle
11 Clamping plate
12 O-ring
Figure 5 — Apparatus for enclosing a specimen in a rubber membrane
4.1.10 Stresses in the specimen
4.1.10.1 To determine the effect of the void ratio on permeability, highly compressible specimens shall be
tested at the relevant stress level.
4.1.10.2 Where a back pressure is applied or where the direction of flow is upward, the application of an
external static load is required to establish equilibrium conditions.
4.1.11 Classes of permeability tests
4.1.11.1 According to the reliability with which the full saturation of the specimen and steady-state of flow is
ensured i.e. how closely the test models the conditions in situ the permeability tests can be classified as presented
in Table 3.
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Table 3 — Classes of permeability tests
Class of quality Controlled degree of saturation? Controlled steady-state flow condition?
1 yes yes
no yes
2
yes no
3 no no
4.1.12 Choice of test arrangement
4.1.12.1 The test arrangement shall be selected as a function of the type of soil to be tested (see Table 4). In
doing so, it shall be checked whether it is necessary to determine the permeability coefficient at a controlled full
saturation with laminar flow, or whether it is sufficient to determine the coefficient without laminar flow being
controlled.
Table 4 — Example for test arrangement as a function of soil type
Means of measuring hydraulic
a
Apparatus Means of measuring water volume
gradient
Two or
Soil type
Compres- One Piezo- Specimen
Triaxial more Pressure Measuring Capillary Specimen
Test mould sion per- piezometric metric tube under
cell piezometric system cylinder tube saturated
meameter tube or burette stress
tubes
(×) × × × (×) × – (×) –
Clay, silt
× – × – – × – × –
× – – × – (×) × × ×
× × × – × × – – –
Fine sand
× – – × × – – × ×
× × × – × × – – –
Medium and
coarse sand
× – – × × – – × (×)
× × (×) – × (×) – – –
Sand-gravel
mixture
× – – – × – – × ×
(×) × × × (×) × – (×) –
Sand-clay
× – × – – × – × –
mixture
× – × × (×) × × × ×
(×) – × × (×) × – – –
Gravel-sand-
clay mixture
× – – × (×) – × × ×
a
equivalent electronic systems with balances, pumps or pressure transducers may also be used
× = suitable (×) = suitable with reservations – = not suitable
4.2 Falling head
4.2.1 Apparatus
The following apparatus is required (see Figure 4):
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a) de-aired water supply unit;
b) reservoir for de-aired water;
c) core sampling or cutting equipment;
d) steel straightedge;
e) compression permeameter (with piezometric tube and loading device).
4.2.2 Test arrangement
4.2.2.1 The permeameter used shall be one working on the compression principle and to which a piezometric
tube shall be connected so as to permit upward flow.
4.2.2.2 The piezometric tube shall be calibrated to allow the volume to be measured accurately, its diameter
–10
being chosen as a function of the permeability of the specimen (e.g. d = 4 mm for k = 10 m/s). The tube should be
weighed before and after the test.
–6
4.2.2.3 The filter blocks in the permeameter shall be sufficiently permeable (i.e. k shall exceed 10 m/s), their
permeability being checked at regular intervals, taking the possible influence of valves and connecting tubing into
account. The permeability of the filter block shall be at least 10 times bigger than the permeability of the sample.
4.2.2.4 Any trapped air shall be removed from the apparatus by filling de-aired water via feeding pipes into the
chamber designed to accommodate the lower filter block. The filter block itself shall be de-aired by boiling in water
and then fitted into the chamber filled with water.
4.2.3 Soil type and specimen dimensions
4.2.3.1 The method described below is suitable for fine-grained soil, especially for clay and silt.
4.2.3.2 The minimum diameter of the specimen shall be 50 mm, and the minimum height 20 mm.
4.2.4 Specimen preparation
4.2.4.1 If the permeability of an undisturbed sample is to be determined, a specimen shall be taken from the
sample using a sampling ring.
4.2.4.2 Disturbed sample material (e.g. manmade fill material) shall be compacted to the required density
using the Proctor test apparatus, for example. A specimen shall then be taken as described above and tested in
the permeameter.
4.2.4.3 Depending on the construction of the apparatus, the ring shall either be introduced directly into the
apparatus, or the specimen shall be pressed out of the ring into a specimen holder which must first be removed
from the apparatus. The end faces shall be carefully levelled off, without producing undue cavities. The specimen
holder shall then be introduced into the permeameter and a rubber ring pressed
...
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