Geotechnical investigation and testing - Geohydraulic testing - Part 4: Pumping tests (ISO 22282-4:2021)

This document establishes requirements for pumping tests as part of geotechnical investigation service
in accordance with EN 1997-1 and EN 1997-2.
This document applies to pumping tests performed on aquifers whose permeability is such that
pumping from a well can create a lowering of the piezometric head within hours or days depending on
the ground conditions and the purpose. It covers pumping tests carried out in soils and rock.
The tests concerned by this document are those intended for evaluating the hydrodynamic parameters
of an aquifer and well parameters, such as:
— permeability of the aquifer,
— radius of influence of pumping,
— pumping rate of a well,
— response of drawdown in an aquifer during pumping,
— skin effect,
— well storage,
— response of recovery in an aquifer after pumping.

Geotechnische Erkundung und Untersuchung - Geohydraulische Versuche - Teil 4: Pumpversuche (ISO 22282-4:2021)

Dieser Teil von ISO 22282 behandelt Anforderungen an Pumpversuche als Teil der geotechnischen Erkundung nach EN 1997-1 und EN 1997-2.
Allgemeine Regeln für die Planung und Ausführung von geohydraulischen Feldversuchen werden in ISO 22282-1 behandelt.
Grundsätzlich besteht ein Pumpversuch aus Folgendem:
- Druckabsenkung durch Abpumpen von Wasser aus einem Brunnen (dem Versuchsbrunnen);
- Messen des abgepumpten Volumens und des Wasserspiegels im Versuchsbrunnen und in den Grundwassermessstellen vor, während und nach dem Pumpen als Funktion der Zeit.
Dieser Teil von ISO 22282 gilt für Pumpversuche in Grundwasserleitern, deren Durchlässigkeit so ist, dass das Abpumpen aus einem Brunnen - in Abhängigkeit von den Bedingungen des Baugrunds und dem Zweck - zu einer Absenkung der piezometrischen Höhe innerhalb von Stunden oder Tagen führen kann. Das Dokument behandelt Pumpversuche in Locker- und Felsgestein.
Bei den durch diesen Teil von ISO 22282 abgedeckten Versuchen handelt es sich um diejenigen, die zur Auswertung der hydrodynamischen Parameter eines Grundwasserleiters und von Brunnenparametern vorgesehen sind, z. B.:
- allgemeiner Durchlässigkeitsbeiwert des Grundwasserleiters;
- Einflussradius des Pumpens;
- Förderrate für einen Brunnen;
- Auswirkung in Bezug auf die Absenkung in einem Grundwasserleiter während des Pumpens;
- Skin-Faktor;
- Brunnenspeicherkoeffizient;
- Auswirkung in Bezug auf die Wiederherstellung in einem Grundwasserleiter nach dem Pumpen.

Reconnaissance et essais géotechniques - Essais géohydrauliques - Partie 4: Essais de pompage (ISO 22282-4:2021)

Ce document traite des exigences relatives aux essais de pompage réalisés dans le cadre d’une mission de reconnaissance géotechnique conformément à l’EN 1997-1 et l’EN 1997-2.
Ce document s’applique aux essais de pompage réalisés sur des formations aquifères dont la perméabilité est telle que le pompage à partir d’un puits peut créer un rabattement du niveau piézométrique en quelques heures ou jours selon les conditions de terrain et l’objectif. Il traite des essais de pompage réalisés dans les sols et les roches.
Les essais concernés par ce document sont ceux destinés à évaluer les paramètres hydrodynamiques d’une formation aquifère et les paramètres du puits, tels que
—    la perméabilité de la formation aquifère,
—    le rayon d’influence du pompage,
—    le débit de pompage d’un puits,
—    la réponse en termes de rabattement dans une formation aquifère pendant le pompage,
—    l’effet pariétal,
—    l’emmagasinement du puits,
—    la réponse en termes de remontée dans une formation aquifère après pompage.

Geotehnično preiskovanje in preskušanje - Hidrogeološke preiskave - 4. del: Črpalni preskus (ISO 22282-4:2021)

General Information

Status
Published
Public Enquiry End Date
09-Jul-2020
Publication Date
25-May-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
15-Apr-2021
Due Date
20-Jun-2021
Completion Date
26-May-2021

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SLOVENSKI STANDARD
SIST EN ISO 22282-4:2021
01-julij-2021
Nadomešča:
SIST EN ISO 22282-4:2012
Geotehnično preiskovanje in preskušanje - Hidrogeološke preiskave - 4. del:
Črpalni preskus (ISO 22282-4:2021)

Geotechnical investigation and testing - Geohydraulic testing - Part 4: Pumping tests

(ISO 22282-4:2021)
Geotechnische Erkundung und Untersuchung - Geohydraulische Versuche - Teil 4:
Pumpversuche (ISO 22282-4:2021)

Reconnaissance et essais géotechniques - Essais géohydrauliques - Partie 4: Essais de

pompage (ISO 22282-4:2021)
Ta slovenski standard je istoveten z: EN ISO 22282-4:2021
ICS:
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
SIST EN ISO 22282-4:2021 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 22282-4:2021
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SIST EN ISO 22282-4:2021
EN ISO 22282-4
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2021
EUROPÄISCHE NORM
ICS 93.020 Supersedes EN ISO 22282-4:2012
English Version
Geotechnical investigation and testing - Geohydraulic
testing - Part 4: Pumping tests (ISO 22282-4:2021)

Reconnaissance et essais géotechniques - Essais Geotechnische Erkundung und Untersuchung -

géohydrauliques - Partie 4: Essais de pompage (ISO Geohydraulische Versuche - Teil 4: Pumpversuche (ISO

22282-4:2021) 22282-4:2021)
This European Standard was approved by CEN on 10 December 2020.

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. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists 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, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22282-4:2021 E

worldwide for CEN national Members.
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SIST EN ISO 22282-4:2021
EN ISO 22282-4:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 22282-4:2021
EN ISO 22282-4:2021 (E)
European foreword

This document (EN ISO 22282-4:2021) has been prepared by Technical Committee ISO/TC 182

"Geotechnics" in collaboration with Technical Committee CEN/TC 341 “Geotechnical Investigation and

Testing” the secretariat of which is held by BSI.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by October 2021, and conflicting national standards shall

be withdrawn at the latest by October 2021.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 22282-4:2012.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: 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, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 22282-4:2021 has been approved by CEN as EN ISO 22282-4:2021 without any

modification.
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SIST EN ISO 22282-4:2021
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SIST EN ISO 22282-4:2021
INTERNATIONAL ISO
STANDARD 22282-4
Second edition
2021-03
Geotechnical investigation and
testing — Geohydraulic testing —
Part 4:
Pumping tests
Reconnaissance et essais géotechniques — Essais géohydrauliques —
Partie 4: Essais de pompage
Reference number
ISO 22282-4:2021(E)
ISO 2021
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SIST EN ISO 22282-4:2021
ISO 22282-4:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
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SIST EN ISO 22282-4:2021
ISO 22282-4:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms, definitions and symbols ............................................................................................................................................................ 2

3.1 Terms and definitions ....................................................................................................................................................................... 2

3.2 Symbols ......................................................................................................................................................................................................... 2

4 Equipment ................................................................................................................................................................................................................... 2

5 Test procedure ........................................................................................................................................................................................................ 3

5.1 Test preparation ..................................................................................................................................................................................... 3

5.1.1 General...................................................................................................................................................................................... 3

5.1.2 Determining the discharge rate for the pumping test ..................................................................... 3

5.2 Arranging the disposal of discharge water ..................................................................................................................... 3

5.3 Executing and equipping the well .......................................................................................................................................... 4

5.3.1 Design of the test well ................................................................................................................................................. 4

5.3.2 Installation procedure .................. ......................................................................................................................... ...... 6

5.3.3 Preparation of the well ............................................................................................................................................... 6

5.4 Executing and equipping the piezometers ......... ............................................................................................................. 6

5.4.1 Installation procedure .................. ......................................................................................................................... ...... 6

5.4.2 Preparation of piezometers .................................................................................................................................... 6

5.5 Execution of the test ........................................................................................................................................................................... 7

5.5.1 General...................................................................................................................................................................................... 7

5.5.2 Pre-pumping monitoring .......................................................................................................................................... 7

5.5.3 Preliminary pumping phase................................................................................................................................... 7

5.5.4 Pumping test .................. .................................................... .................................................................................................. 7

5.5.5 Post-pumping monitoring ....................................................................................................................................... 8

5.6 Uncertainty of measurement ...................................................................................................................................................... 8

5.7 Interruptions in pumping .............................................................................................................................................................. 9

5.8 Decommissioning ................................................................................................................................................................................. 9

6 Test results .................................................................................................................................................................................................................. 9

7 Reports............................................................................................................................................................................................................................ 9

7.1 Field report ................................................................................................................................................................................................ 9

7.1.1 General...................................................................................................................................................................................... 9

7.1.2 Installation record .......................................................................................................................................................10

7.1.3 Record of measured values and test results ..........................................................................................10

7.2 Test report ................................................................................................................................................................................................11

Annex A (informative) Record of measured values and test results of the pumping test —

Example .......................................................................................................................................................................................................................12

Annex B (informative) Determining the pumping test discharge .......................................................................................15

Annex C (informative) Interpretation of the pumping test results ....................................................................................19

Bibliography .............................................................................................................................................................................................................................27

© ISO 2021 – All rights reserved iii
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SIST EN ISO 22282-4:2021
ISO 22282-4:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 182, Geotechnics, in collaboration with

the European Committee for Standardization (CEN) Technical Committee CEN/TC 341, Geotechnical

investigation and testing, in accordance with the Agreement on technical cooperation between ISO and

CEN (Vienna Agreement).

This second edition cancels and replaces the first edition (ISO 22282-4:2012), which has been

technically revised.
The main changes compared to the previous edition are as follows:
— editorial changes;
— correction of formulae.
A list of all parts in the ISO 22282 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved
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SIST EN ISO 22282-4:2021
ISO 22282-4:2021(E)
Introduction

General rules on the planning and execution of geohydraulic field tests are covered by ISO 22282-1.

A pumping test consists in principle of:

— drawing down the piezometric surface of the groundwater by pumping from a well (the test well);

— measuring the pumped discharge and the water level in the test well and piezometers, before, during

and after pumping, as a function of time.
© ISO 2021 – All rights reserved v
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SIST EN ISO 22282-4:2021
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SIST EN ISO 22282-4:2021
INTERNATIONAL STANDARD ISO 22282-4:2021(E)
Geotechnical investigation and testing — Geohydraulic
testing —
Part 4:
Pumping tests
1 Scope

This document establishes requirements for pumping tests as part of geotechnical investigation service

in accordance with EN 1997-1 and EN 1997-2.

This document applies to pumping tests performed on aquifers whose permeability is such that

pumping from a well can create a lowering of the piezometric head within hours or days depending on

the ground conditions and the purpose. It covers pumping tests carried out in soils and rock.

The tests concerned by this document are those intended for evaluating the hydrodynamic parameters

of an aquifer and well parameters, such as:
— permeability of the aquifer,
— radius of influence of pumping,
— pumping rate of a well,
— response of drawdown in an aquifer during pumping,
— skin effect,
— well storage,
— response of recovery in an aquifer after pumping.
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.

ISO 14688-1, Geotechnical investigation and testing — Identification and classification of soil — Part 1:

Identification and description

ISO 14689, Geotechnical investigation and testing — Identification, description and classification of rock

ISO 18674-4, Geotechnical investigation and testing — Geotechnical monitoring by field instrumentation —

Part 4: Measurement of pore water pressure: Piezometers

ISO 22282-1, Geotechnical investigation and testing — Geohydraulic testing — Part 1: General rules

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 2021 – All rights reserved 1
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SIST EN ISO 22282-4:2021
ISO 22282-4:2021(E)
3 Terms, definitions and symbols
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 22282-1 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.2 Symbols
Symbol Designation Unit
D drilled diameter of the well m
d thickness of the aquifer m
L wetted length of screen of the perforated pipe placed in the well m
Q flow rate m /s

Q discharge rate, assessed pumping discharge at the end of the well preparation m /s

Q discharge rate of the pumping test m /s
S storage coefficient —
T transmissivity m /s
t time s
v velocity —
a slope of the line that characterizes the drawdown in the well —

b ordinate at the origin of the line that characterizes the drawdown in the well —

c conventional drawdown unit of the preliminary pump discharge —

d size which may be interpolated from the grading curve, of the square sieve mesh of side d —

for which the weight percent of undersize is equal to N percent

e distance between the bottom of the well and the surface of the unconfined groundwater at m

rest in an aquifer
Δh drawdown of the water level in the well m
Δh' drawdown of the water level in the well after 2 h m

Δh drawdown of the water level in the well, set during the preliminary test and not to be m

exceeded
Δh maximum drawdown of the water level in the well during the pumping test m
max
4 Equipment
The following equipment and instruments shall be used to conduct a pumping test:
a) a test well and piezometers in accordance with ISO 18674-4;

b) a pump and associated pipework capable of pumping from the test well; the pumps shall be equipped

with a suitably long discharge pipe so that the water from the pump is discharged sufficiently far

away so that it does not affect the test area; the capacity of the pump shall be sufficient to extract

from the well a discharge at least equal to that corresponding to that estimated to achieve the

maximum planned drawdown;

NOTE Pumping tests are commonly carried out using electric submersible pumps, installed within the

test well. However, depending on conditions, pumping tests can also be carried out using suction pumps

located at the surface, airlift equipment, or special dewatering equipment such as well points or eductors.

2 © ISO 2021 – All rights reserved
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SIST EN ISO 22282-4:2021
ISO 22282-4:2021(E)

c) a system for regulating and measuring the discharge rate (m /s); devices for measuring the

discharge rate shall be suitably calibrated and shall be accurate for a range of flow rates anticipated

during the test;

d) a system for measuring the water level in the test well and piezometers; the turbulence in the test

well caused by pumping shall be considered; the devices shall be capable of measuring water levels

over the range of drawdowns anticipated during the test;
e) a time measuring and/or recording device, reading in seconds.
5 Test procedure
5.1 Test preparation
5.1.1 General

When preparing a pumping test, there are a number of things to investigate and consider in advance,

such as:

— basic information on the ground and groundwater conditions according to ISO 22282-1;

— the required drawdown and/or the required discharge rate during the test;

— the discharge point for the pumped water and its location relative to the test well;

— the duration of the test.
5.1.2 Determining the discharge rate for the pumping test

The discharge rate Q shall be estimated to ensure that the test well can yield sufficient water, to allow

a pump of appropriate capacity to be selected, and to ensure that the discharge can be accepted at the

agreed disposal point.
The discharge rate can be estimated by one or more of the following methods:
— based on the purpose of the test and experience of local conditions;

— by theoretical assessment of the well capacity, according to the method described in Annex B;

— by analysis of information from the preliminary pumping phase, according to the method described

in Annex B.
5.2 Arranging the disposal of discharge water

It is presupposed that the disposal of discharge water is in accordance with relevant rules and

regulations.

If the discharge water is not disposed of via an engineered sewer network, it shall be disposed of at

sufficient distance from the test well that it will not have a significant impact on the observed pattern

of groundwater lowering.
© ISO 2021 – All rights reserved 3
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SIST EN ISO 22282-4:2021
ISO 22282-4:2021(E)
5.3 Executing and equipping the well
5.3.1 Design of the test well

The test well shall be designed to satisfy the following criteria (see Figure 1):

— of sufficient depth to penetrate below the groundwater level in the strata of interest; if the test well

does not fully penetrate the aquifer, it shall penetrate the saturated part of the aquifer to a depth of

at least 25 times the well screen diameter with a minimum of 3 m;

— of sufficient drilled diameter to accommodate the necessary filter materials and well screen of

sufficient diameter to accommodate pumping equipment of adequate capacity to achieve the

required discharge rate;

— with sufficient length and capacity of well screen to ensure that the required discharge rate can be

achieved;

— to have appropriate filter material to ensure that the discharge water contains an acceptably low

sediment content to avoid the risk of pump damage and ground settlement as a result of the removal

of fine particles from the soil; where the well is constructed in a stable rock, it may be possible to

construct a test well without the need for filter material.

The filter material shall be a highly permeable granular material of closely controlled particle size and

be formed of grains of inert minerals in relation to the aquifer groundwater chemistry (e.g. quartz,

feldspar). In granular soils, the filter's grading curve shall satisfy the double inequality:

5 d ≤ d ≤ 5 d
15 soil 15 filter 85 soil

where d designates the characteristic size of the filter or of the ground in place, such that the mass of

the soil fraction passing through a sieve with a square mesh of side d represents N % of the total mass

of material.

In fine grained soils or where the well screen is equipped with a geotextile mesh designed to act as a

filter, the filter material’s purpose is to backfill the annular space between the outside of the well screen

and the borehole wall. In those circumstances the filter media should be highly permeable coarse sand

or fine gravel, with a permeability coefficient at least 100 times that of the soil or rock being tested.

The thickness of the annular space for the filter pack shall be at least 50 mm. The inner diameter of the

test well shall be selected according to the purpose.
4 © ISO 2021 – All rights reserved
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SIST EN ISO 22282-4:2021
ISO 22282-4:2021(E)
Key
1 well screen (slotted tube) 7 plain tube
2 filter material (filter pack) 8 device for measuring the water level
3 submersible pump 9 base of the screen
4 borehole casing L filter length
5 tube for measuring the water level D drilled diameter of the well
6 sealing plug
Figure 1 — Test well equipped for a pumping test — Example
© ISO 2021 – All rights reserved 5
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SIST EN ISO 22282-4:2021
ISO 22282-4:2021(E)
5.3.2 Installation procedure

The test well shall be constructed in a similar way to piezometers in accordance with ISO 18674-4.

Great care shall be taken when installing the well materials. Particular attention shall be paid to the

following:

— The well screen shall be lowered into the borehole to the specified level and shall be installed

centrally in the well, with the top and bottom of the screen located at the design level. Care shall

be taken that the joints of the screen and casing do not leak, and that the screen and casing are

installed vertically and straight.

— If necessary, filter material shall be inserted in the annular space between the screen and the temporary

casing (or borehole wall). The filter material shall be placed progressively in stages to reduce the risk

of a blockage in the annular space. The filter material should be placed via a tremie pipe.

— If necessary, a sealing plug of low permeability material (such as bentonite) shall be created in the

annular space between the borehole wall and the well casing immediately above the filter material.

The purpose of the sealing plug is to prevent infiltration of surface water, or water from other

aquifers, into the well screen.
5.3.3 Preparation of the well

Prior to the pumping test the well shall be developed to increase the permeability of the soil around the

shell by washing, and to remove any drilling residues and mobile soil particles that could be entrained

by the water flow into the well. Such particles could clog the filter and damage the test pump.

Development shall be carried out by means of pumping. Possible methods include airlifting or pumping

using a robust pump that is not damaged by the presence of particles in the discharge water. If airlift

pumping is used, care shall be taken to avoid injecting air into the ground, as air bubbles in the ground

can affect the permeability.

Other methods for well development may be used in combination with pumping, including:

— jetting with water inside the well screen;

— surging or swabbing inside the well screen to induce water flow into and out of the well;

— chemical treatment (e.g. use of acids in carbonate rocks).
5.4 Executing and equipping the piezometers
5.4.1 Installation procedure
Piezometers shall be installed in accordance with ISO 18674-4.

The piezometer tubes shall be installed at such a depth that the influence of the test well can be observed

and recorded adequately. Where possible, the piezometer closest to the test well shall be located at the

same depth as the bottom of the test well.
5.4.2 Preparation of piezometers
Before commencement of the
...

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