SIST EN 12716:2019
(Main)Execution of special geotechnical work - Jet grouting
Execution of special geotechnical work - Jet grouting
This European Standard establishes general principles for the execution of jet grouting works.
The jet grouting processes should be distinguished from the grouting processes covered by EN 12715.
Ausführung von Arbeiten im Spezialtiefbau - Düsenstrahlverfahren
Diese Europäische Norm legt allgemeine Grundsätze für die Ausführung von Düsenstrahlarbeiten fest.
ANMERKUNG Das Düsenstrahlverfahren unterscheidet sich von den in EN 12715 erfassten Injektionsverfahren.
Exécution des travaux géotechniques spéciaux - Jet-grouting
1 Domaine d'application
La présente Norme européenne établit des principes généraux en vue de l’exécution des travaux de solciment
par jet.
RERMARQUE Il convient de distinguer les procédés d’exécution de sol-ciment par jet des procédés d'injection
(« grouting ») couverts par l'EN 12715.
Izvedba posebnih geotehničnih del - Injektiranje pod visokimi pritiski
Ta evropski standard določa splošna načela za izvedbo injektiranja pod visokimi pritiski.
Postopki injektiranja pod visokimi pritiski se razlikujejo od postopkov injektiranja, ki jih obravnava standard EN 12715.
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.WLVNLAusführung von Arbeiten im Spezialtiefbau - DüsenstrahlverfahrenExécution des travaux géotechniques spéciaux - Jet-groutingExecution of special geotechnical work - Jet grouting93.020Zemeljska dela. Izkopavanja. Gradnja temeljev. Dela pod zemljoEarthworks. Excavations. Foundation construction. Underground worksICS:Ta slovenski standard je istoveten z:EN 12716:2018SIST EN 12716:2019en,fr,de01-marec-2019SIST EN 12716:2019SLOVENSKI
STANDARDSIST EN 12716:20021DGRPHãþD
SIST EN 12716:2019
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 12716
December
t r s z ICS
{ uä r t r Supersedes EN
s t y s xã t r r sEnglish Version
Execution of special geotechnical work æ Jet grouting Exécution des travaux géotechniques spéciaux æ Jetægrouting
Ausführung von Arbeiten im Spezialtiefbau æ Düsenstrahlverfahren This European Standard was approved by CEN on
t z September
t r s zä
egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Serbiaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä
EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Rue de la Science 23,
B-1040 Brussels
9
t r s z CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN
s t y s xã t r s z ESIST EN 12716:2019
EN 12716:2018 (E) 2 Contents Page European foreword . 4 1 Scope . 5 2 Normative references . 5 3 Terms and definitions . 5 4 Information needed for the execution of the work . 8 4.1 General . 8 4.2 Specific requirements . 8 5 Geotechnical investigation . 10 5.1 General . 10 5.2 Specific Requirements . 10 6 Materials and products . 11 6.1 General . 11 6.2 Cement . 11 6.3 Water . 11 6.4 Bentonite . 12 6.5 Additions . 12 6.6 Admixtures . 12 6.7 Reinforcement . 12 7 Considerations related to design. 12 7.1 General . 12 7.2 Geometry . 14 7.3 Strength and Deformation Characteristics . 14 7.4 Permeability . 15 8 Execution . 15 8.1 General . 15 8.2 Equipment . 16 8.3 Preparation of the site . 17 8.4 Drilling and Tolerances . 17 8.5 Jet grouting . 18 8.6 Spoil Return . 18 8.7 Placing the reinforcement . 18 9 Supervision, testing and monitoring . 18 9.1 General . 18 9.2 Preliminary tests . 19 9.3 Supervision and process testing . 19 9.4 Testing of the jet grouted elements . 20 9.4.1 Testing to assess geometry . 20 9.4.2 Mechanical tests . 20 9.4.3 Permeability tests . 21 9.5 Monitoring . 21 10 Records . 21 10.1 Documents available on site . 21 10.2 Documents to be produced on site. 22 SIST EN 12716:2019
EN 12716:2018 (E) 3 11 Special requirements . 22 11.1 Compliance with national and European Standards. 22 11.2 Site safety . 23 11.3 Protection of the environment . 23 Annex A (informative)
Determination of the material strength . 24 Annex B (informative)
Sample Quality. 26 Annex C (normative)
Direct and indirect tests and quality controls . 29 Annex D (informative)
Examples of site records of jet grouting works . 31 Annex E (informative)
Degree of obligation of the provisions . 34 Bibliography . 37
SIST EN 12716:2019
EN 12716:2018 (E) 4 European foreword This document (EN 12716:2018) has been prepared by Technical Committee CEN/TC 288 “Execution of special geotechnical works”, the secretariat of which is held by AFNOR. 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 June 2019, and conflicting national standards shall be withdrawn at the latest by June 2019. 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 12716:2001. The general scope of TC 288 is the standardization of the execution procedures for geotechnical works (including testing and control methods) and of the required material properties. WG 17 has been charged to revise EN 12716:2001, with the subject area of jet grouting. The design, planning and execution of jet grouting call for experience and knowledge in this specialized field. The execution phase requires skilled and qualified personnel and the present standard cannot replace the expertise of specialist contractors. The document has been prepared to complement EN 1997-1, Eurocode 7: Geotechnical design — Part 1: General rules, and EN 1997-2, Eurocode 7 — Geotechnical design — Part 2: Ground investigation and testing. Clause 7, Considerations related to design, of this document expands on design only where necessary (e.g. the detailing of reinforcement), but provides full coverage of the construction and supervision requirements. This standard contains additional requirements on cement complementing the respective provisions of EN 197-1 and of EN 1008. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 12716:2019
EN 12716:2018 (E) 5 1 Scope This document establishes general principles for the execution of jet grouting works. NOTE The jet grouting processes is distinguished from the grouting processes covered by EN 12715. 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. EN 197-1, Cement — Part 1: Composition, specifications and conformity criteria for common cements EN 206, Concrete — Specification, performance, production and conformity EN 480-4, Admixtures for concrete, mortar and grout — Test methods — Part 4: Determination of bleeding of concrete EN 934-4:2009, Admixtures for concrete, mortar and grout — Part 4: Admixtures for grout for prestressing tendons — Definitions, requirements, conformity, marking and labelling EN 1008, Mixing water for concrete — Specification for sampling, testing and assessing the suitability of water, including water recovered from processes in the concrete industry, as mixing water for concrete EN 1997-1:2004, Eurocode 7: Geotechnical design — Part 1: General rules EN 1997-2, Eurocode 7 — Geotechnical design — Part 2: Ground investigation and testing EN 12390-2, Testing hardened concrete — Part 2: Making and curing specimens for strength tests EN 12390-3, Testing hardened concrete — Part 3: Compressive strength of test specimens EN 16228-1:2014, Drilling and foundation equipment — Safety — Part 1: Common requirements EN 16228-6, Drilling and foundation equipment — Safety — Part 6: Jetting, grouting and injection equipment EN ISO 10414-1:2008, Petroleum and natural gas industries — Field testing of drilling fluids — Part 1: Water-based fluids (ISO 10414-1:2008) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses:
IEC Electropedia: available at http://www.electropedia.org/
ISO Online browsing platform: available at http://www.iso.org/obp SIST EN 12716:2019
EN 12716:2018 (E) 6 3.1 jet grouting process of hydraulic disaggregation of the soil or weak rock, which is achieved by a high energy jet of a fluid, which can be the cementing agent itself, and its concurrent mixing with, and partial replacement by grout, to create a jet grouted element after hardening of the hydraulic binder 3.2 jet grouted element volume of soil or weak rock treated through a single borehole 3.3 jet grouted structure assembly of jet grouted elements which are partially or fully interlocked 3.4 sub-vertical jet grouting treatment performed from a vertical or sub-vertical borehole (within ± 20° from the vertical plane) 3.5 sub-horizontal jet grouting treatment performed from a horizontal or sub-horizontal borehole (within ± 20° from the horizontal plane) 3.6 inclined jet grouting treatment performed at inclinations other than sub-vertical or sub-horizontal 3.7 single system jet grouting with a single fluid which is the grout itself 3.8 double system single system with the addition of an air shroud around the jet 3.9 triple system double system using water for the jet with the optional addition of an air shroud around the jet and the concurrent addition of grout through a separate opening below the jet Note 1 to entry: In some cases the addition of air can be fully or partially omitted. 3.10 jet grouting rig rotary rig able to automatically regulate the rotation and translation of the jet grouting string and monitor 3.11 jet grouting string jointed rods, with single, double or triple inner conduit, which convey the jet grouting fluid(s) to the monitor SIST EN 12716:2019
EN 12716:2018 (E) 7 3.12 monitor tool mounted close to the end of the jet grouting string holding the nozzle(s) 3.13 nozzle device attached to the monitor to generate the high velocity jet 3.14 radius of influence distance of hydraulic disaggregation of soil by the jet, measured from the axis of the monitor 3.15 spoil return surplus mixture of hydraulically disaggregated soil or weak rock and introduced fluids arising from the jet grouting process, and normally flowing to the ground surface via the annulus of the jetting borehole 3.16 jet grouting parameters parameters defined as: — number and diameter of nozzle(s); — pressure of the fluid(s); — flow rate of the fluid(s); — pressure and flow of the air (if used); — grout or fluid composition; — rotation speed of the jet grouting string; — rate of withdrawal or insertion of the jet grouting string 3.17 precutting (multiple-phase jet grouting) method in which the jet grouting of an element is preceeded by a preliminary phase of hydraulic disaggregation 3.18 jet grouted material material which constitutes the body of a jet grouted element 3.19 grout pumpable material (suspension, solution, emulsion) composed of water, binder and additives, that is used as high energy fluid or for cementing and which develops strength, e.g. measured as unconfined compressive strength, over time 3.20 hydraulic binder cement or similar product used in aqueous suspensions to produce grout SIST EN 12716:2019
EN 12716:2018 (E) 8 3.21 jetted concrete pile element where the jetted material is replaced with concrete through a separate tremie pipe replacing the materials contained in the cavity 3.22 sample quality class classification of the samples extracted from the jet grouted element according to their surface, structure, amount of irregularities and composure 3.23 geotechnical equivalent zone group of soil layers, clearly distinguished from the neighbour zones, that can be treated by a uniform set of jetting parameters 4 Information needed for the execution of the work 4.1 General 4.1.1 Prior to the execution of the work, all necessary information shall be made available. 4.1.2 This information shall include: — any legal or statutory restrictions; — the location of main grid lines for setting out element positions; — the locations and conditions of structures, roads, services, etc. adjacent to the work, including any necessary surveys; — a suitable quality management system, including supervision, monitoring and testing. — the geometry of the site (boundary conditions, topography, access, slopes, etc.); — available space for storage, treatment and/or disposal of spoil; — the existing underground structures, services, and archaeological constraints; potential presence of unexploded ordnance and its location; — the environmental restrictions, including noise, vibration, pollution; — the future or ongoing activities such as dewatering, tunnelling, deep excavations. 4.2 Specific requirements 4.2.1 The specific requirements shall cover, where relevant: — execution specifications; — materials strength and stiffness required; — the degree of water tightness required; — previous use of the site; SIST EN 12716:2019
EN 12716:2018 (E) 9 — adjacent structures and their foundations (types, state, loads and geometry); — geotechnical information and data as specified in Clause 5; — presence of any obstructions in the ground (old masonry, anchors, concrete, blocks and boulders, etc.); — certificate or written confirmation of removal of all unexploded ordnance; — presence of headroom restrictions; — presence of natural and/or man-made cavities (mines, etc.); — presence of contaminated ground and type, extent and degree of contamination; — any specific requirements for the jet grouting works, in particular those pertaining to tolerances, quality of materials and methods and frequency of testing; — where available, previous experience with jet grouting or other grouting works pertinent or relevant to the site; — proposed adjacent enabling or advance works such as underpinning, pre-treatment of soil, dewatering; — the extent and type of instrumentation required for monitoring potentially affected structures. 4.2.2 Necessity, extent, procedure and content for any survey on the conditions of structures, roads, services, grid lines, etc. adjacent to the works area shall be established. 4.2.3 The survey shall be carried out and be available prior to the commencement of the works and its conclusions shall be used to define the threshold values for any movement which may affect adjacent structures by the works area constructions. 4.2.4 Any additional or deviating requirements shall be established before the commencement of the works and the quality control system shall be suitably amended. NOTE Such additional or deviating requirements can be e.g.: — reduced or increased geometrical construction deviations; — application of different or varying grouting materials; — special anchorage or quality of contact of jet grouting elements to underlying rock; — reinforcement; — cut-off levels; — extensive manual excavation. SIST EN 12716:2019
EN 12716:2018 (E) 10 5 Geotechnical investigation 5.1 General 5.1.1 The general requirements for site investigation are contained in EN 1997-2 and the relevant national documents. 5.1.2 The depth and the extent of the geotechnical investigation should be sufficient to identify all ground formations and layers affected by the jet grouting works, to determine the relevant properties of the ground and to determine the ground conditions. 5.1.3 Relevant experience of the execution of comparable jet grouting works under similar conditions and/or in the vicinity of the site should be taken into account when determining the extent of site investigation. 5.1.4 The ground investigation report shall be available, to allow for reliable design and execution of the jet grouting works. 5.1.5 The sufficiency of the geotechnical investigation for the design and execution of the jet grouting works shall be verified. 5.1.6 If the geotechnical investigations are not sufficient, a supplementary investigation shall be conducted. 5.2 Specific Requirements 5.2.1 Particular attention shall be paid to the following aspects, which are relevant to the execution of jet grouting: — the ground level at any point of investigation or testing relative to the recognized national datum or to a fixed reference chart datum; — piezometric levels of all water-tables and permeability of the soils; — presence of coarse, highly permeable soils or cavities (natural or artificial), which can cause sudden losses of grout and instability of the borehole during jetting or which can cause a sudden drop of fluid level and thus can require special measures; — presence, strength and deformation characteristics of cohesive soils, such as clay or peat, which can cause difficulties during jetting; — presence of boulders or obstructions which can cause shadows during jetting and, an assessment of their size and frequency, when applicable; — presence, position, strength of hard rock or other hard materials which can cause difficulties during drilling and may require the use of special tools; — presence, extent and thickness of any strata that can be sensitive to water infiltration or additional hydrostatic pressure caused by jetting; — strata where high ground-water velocities exist that could wash out the fresh jet grouted material; — detrimental chemistry of groundwater, soil and rock, and water temperatures if required; SIST EN 12716:2019
EN 12716:2018 (E) 11 — presence of pre-treated soil, which can have an adverse effect during jetting; — mining beneath the site; — site stability problems (slope stability for instance). 5.2.2 The piezometric levels of the various water-tables existing on the site shall be monitored separately and over a sufficient period of time to estimate the highest piezometric levels which can occur during jet grouting. 5.2.3 Particular attention shall be paid to artesian conditions. 5.2.4 The relevant properties of the soils shall be determined by laboratory tests and/or in situ tests over the full depth of the jet grouting elements and to a certain depth below their base. 5.2.5 When jet grouting elements are required to connect to the rock, the level of the rock surface shall be determined and where relevant its properties including its strength, the degree of weathering and the extent and direction of fissuring. 6 Materials and products 6.1 General 6.1.1 The constituents shall meet the requirements set in the respective European Standards, the provisions valid for the place of use and those given in the project specification. 6.1.2 The sources of supply for constituents shall be documented and shall not be changed without prior notification. 6.2 Cement 6.2.1 Cement for jet grouting shall comply with EN 197-1. 6.2.2 The selection with respect to exposure classes shall comply with EN 206. 6.2.3 Hydraulic binders other than cement may be used when the required performance is proven by tests or respective regulations, certificates or approvals. 6.2.4 The use of cement with high sulphate resistance (i.e. free of C3A-Tricalciumaluminate) shall comply with the provisions valid in the place of use. NOTE They are used for instance in cool, wet environments with presence of sulphate (e.g. seawater structures). Where there are no local regulations, comparable experience and/or specific studies are necessary. 6.2.5 Calcium aluminate cement shall not be used. 6.2.6 Type II addition including fly ash, silica fume (as defined in EN 206) and ground granulated blast furnace slag may be used as cement replacement. 6.3 Water Mixing water shall comply with EN 1008 and EN 206. SIST EN 12716:2019
EN 12716:2018 (E) 12 6.4 Bentonite 6.4.1 A distinction should be made between calcium bentonite, natural sodium bentonite and activated bentonite, which is a sodium bentonite produced from natural calcium bentonite by ion exchange. NOTE 1 Bentonite is clay containing mainly the mineral montmorillonite. 6.4.2 Bentonite used in grout shall not contain harmful constituents in such quantities as can be detrimental to jet grouting elements or their reinforcement to an unacceptable degree. 6.4.3 The chemical and mineralogical composition of the bentonite shall be known. 6.5 Additions The use of additions shall comply with EN 206. 6.6 Admixtures Admixtures used shall comply with EN 206. NOTE 1 The admixtures used for jet grouting can be: — water reducing/plasticizing; — high range water reducing/super-plasticizing; and — anti-wash-out — set retarding; — set accelerators. NOTE 2 Admixtures can be used: — to minimize bleeding and segregation that might otherwise result from a high water content; — to control the workability time of the grout. 6.7 Reinforcement Where reinforcement is used, the material shall comply with the relevant European product standard. 7 Considerations related to design 7.1 General 7.1.1 Jet grouting can be applied in either temporary or permanent works for different purposes: — to create structural elements; — to create permeability reducing elements; or — a combination of both. 7.1.2 The design of jet grouting works should specify whether borehole collars are to be located above or below the water table or artesian head. SIST EN 12716:2019
EN 12716:2018 (E) 13 7.1.3 Wherever the borehole collars are located below the water table or artesian head, special measures shall be taken into account, in order to avoid piping through the boreholes. 7.1.4 The specified physical properties and geometry of jet grouted structures shall be defined in the design. 7.1.5 Site conditions which may influence the working sequence of the elements shall be specified. 7.1.6 When relevant, the detailed execution sequence should be shown on the printed or electronic execution drawings and/or models. 7.1.7 Where no comparable previous experience is available representative preliminary field tests shall be carried out, using the equipment, materials and techniques proposed for the main jet grouting works. 7.1.8 To ensure a consistent result in the preliminary in situ test, at least one jet grouted element should be constructed with a given working procedure. In significantly heterogeneous ground conditions more test elements and different working procedures should be necessary for approval. 7.1.9 Where the jet grouted material is to be subjected to aggressive or temperature sensitive environment, the preliminary in situ tests should be preceded by specified laboratory tests on samples of the soil to be treated and the grout, mixed in proportions encompassing the working range envisaged. 7.1.10 The determination of the characteristic material strength as part of the supervision, testing and monitoring shall be made by testing of samples, preferably of sample quality class A and B according to Annex B, taken from the jet grouting body itself either by core drilling, fresh sampling or from spoil return. NOTE The reference geometry of samples for this purpose is a
...
SLOVENSKI STANDARD
oSIST prEN 12716:2017
01-junij-2017
,]YHGEDSRVHEQLKJHRWHKQLþQLKGHO,QMHNWLUDQMHSRGYLVRNLPLSULWLVNL
Execution of special geotechnical work - Jet grouting
Ausführung von Arbeiten im Spezialtiefbau - Düsenstrahlverfahren
Exécution des travaux géotechniques spéciaux - Colonnes, panneaux et structures de
sol-ciment réalisés par jet
Ta slovenski standard je istoveten z: prEN 12716
ICS:
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
oSIST prEN 12716:2017 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 12716:2017
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oSIST prEN 12716:2017
DRAFT
EUROPEAN STANDARD
prEN 12716
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2017
ICS 93.020 Will supersede EN 12716:2001
English Version
Execution of special geotechnical work - Jet grouting
Exécution des travaux géotechniques spéciaux - Jet Ausführung von Arbeiten im Spezialtiefbau -
grouting Düsenstrahlverfahren
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 288.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12716:2017 E
worldwide for CEN national Members.
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oSIST prEN 12716:2017
prEN 12716:2017 (E)
Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Information needed for the execution of the work . 8
4.1 General . 8
4.2 Specific requirements . 8
5 Geotechnical investigation . 10
5.1 General . 10
5.2 Specific Requirements . 10
6 Materials and products . 11
6.1 General . 11
6.2 Cement . 11
6.3 Water . 12
6.4 Bentonite . 12
6.5 Additions . 12
6.6 Admixtures . 12
6.7 Reinforcement . 12
7 Considerations related to design. 13
7.1 General . 13
7.2 Geometry . 14
7.3 Strength and Deformation Characteristics . 14
7.4 Permeability . 15
8 Execution . 15
8.1 General . 15
8.2 Equipment . 16
8.3 Preparation of the site . 17
8.4 Drilling and Tolerances . 17
8.5 Jet grouting . 18
8.6 Spoil Return . 18
8.7 Placing the reinforcement . 18
9 Supervision, testing and monitoring . 18
9.1 General . 18
9.2 Preliminary tests . 19
9.3 Supervision and process testing . 19
9.4 Testing of the jet grouted elements . 20
9.4.1 Testing to assess geometry . 20
9.4.2 Mechanical tests . 21
9.4.3 Permeability tests . 21
9.5 Monitoring . 21
10 Records . 21
10.1 Documents available on site . 21
10.2 Documents to be produced on site. 22
2
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oSIST prEN 12716:2017
prEN 12716:2017 (E)
11 Special requirements . 22
11.1 Compliance with national and European standards . 22
11.2 Site safety . 23
11.3 Protection of the environment . 23
Annex A (informative) Determination of the material strength for structural design . 24
Annex B (informative) Sample Quality . 26
Annex C (normative) Direct and indirect tests and quality controls . 29
Annex D (informative) Examples of site records of jet grouting works . 31
Annex E (informative) Degree of obligation of the provisions . 34
Bibliography . 37
3
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oSIST prEN 12716:2017
prEN 12716:2017 (E)
European foreword
This document (prEN 12716:2017) has been prepared by Technical Committee CEN/TC 288 “Execution
of special geotechnical works”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 12716:2001.
The general scope of TC 288 is the standardization of the execution procedures for geotechnical works
(including testing and control methods) and of the required material properties. WG 17 has been
charged to revise EN 12716:2001, with the subject area of jet grouting.
The design, planning and execution of jet grouting call for experience and knowledge in this specialized
field. The execution phase requires skilled and qualified personnel and the present standard cannot
replace the expertise of specialist contractors.
The document has been prepared to complement EN 1997-1, Eurocode 7: Geotechnical design ― Part 1:
General rules and EN 1997-2, Eurocode 7 ― Geotechnical design ― Part 2: Ground investigation and
testing. Clause 7 “Considerations related to design” of this European Standard expands on design only
where necessary (e.g. the detailing of reinforcement), but provides full coverage of the construction and
supervision requirements.
This standard contains additional requirements on cement complementing the respective provisions of
EN 197-1 and of EN 1008.
4
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oSIST prEN 12716:2017
prEN 12716:2017 (E)
1 Scope
This European Standard establishes general principles for the execution of jet grouting works.
NOTE The jet grouting processes is distinguished from the grouting processes covered by EN 12715.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN 197-1, Cement - Part 1: Composition, specifications and conformity criteria for common cements
EN 206, Concrete — Specification, performance, production and conformity
EN 480-4, Admixtures for concrete, mortar and grout - Test methods - Part 4: Determination of bleeding of
concrete
EN 1008, Mixing water for concrete - Specification for sampling, testing and assessing the suitability of
water, including water recovered from processes in the concrete industry, as mixing water for concrete
EN 12390-2, Testing hardened concrete - Part 2: Making and curing specimens for strength tests
EN 12390-3, Testing hardened concrete - Part 3: Compressive strength of test specimens
EN 12504-1, Testing concrete in structures - Part 1: Cored specimens - Taking, examining and testing in
compression
EN 16228-1:2014, Drilling and foundation equipment - Safety - Part 1: Common requirements
EN 16228-6, Drilling and foundation equipment - Safety - Part 6: Jetting, grouting and injection equipment
EN 1993-1-5, Eurocode 3 - Design of steel structures - Part 1-5: Plated structural elements
EN 1997 (all parts), Eurocode 7 - Geotechnical design - Part 2: Ground investigation and testing
1
EN 1997-1:2004, Eurocode 7: Geotechnical design — Part 1: General rules
ASTM D6910, Standard Test Method for Marsh Funnel Viscosity of Clay Construction Slurries
ASTM C1741, Standard Test Method for Bleed Stability of Cementitious Post-Tensioning Tendon Grout
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
jet grouting
hydraulic disaggregation of the soil or weak rock and its mixing with, and partial replacement by grout
Note 1 to entry: The disaggregation is achieved by means of a high energy jet of a fluid which can be the grout
itself. The minimum operating pressure to create the jet energy shall be greater than 25 MPa.
1
As impacted by EN 1997-1:2004/A1:2013 and EN 1997-1:2004/AC:2009.
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3.2
jet grouted element
volume of soil treated through a single borehole
3.3
jet grouted structure
assembly of jet grouted elements which are partially or fully interlocked
3.4
sub-vertical jet grouting
treatment performed from a vertical or sub-vertical borehole (within ± 20° from the vertical plane)
3.5
sub-horizontal jet grouting
treatment performed from a horizontal or sub-horizontal borehole (within ± 20° from the horizontal
plane)
3.6
inclined jet grouting
treatment performed at inclinations other than sub-vertical or sub-horizontal
3.7
single system
jet grouting with a single fluid which is the grout itself
3.8
double system
single system with the addition of an air shroud around the jet
3.9
treatment zone
area treated by jet grouting where uniform soil properties prevail and uniform jet grout parameters are
applied
3.10
triple system
double system using water for the jet with the optional addition of an air shroud around the jet and the
concurrent addition of grout through a separate opening below the jet
Note 1 to entry: In some cases the addition of air can be fully or partially omitted.
3.11
jet grouting rig
rotary rig able to automatically regulate the rotation and translation of the jet grouting string and tool
3.12
jet grouting string
jointed rods, with single, double or triple inner conduit, which convey the jet grouting fluid(s) to the
monitor
3.13
monitor
tool mounted close to the end of the jet grouting string holding the nozzle(s)
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3.14
nozzle
device attached to the monitor to generate the high velocity jet
3.15
radius of influence
distance of hydraulic disaggregation of soil by the jet, measured from the axis of the monitor
3.16
spoil return
surplus mixture of hydraulically disaggregated soil or weak rock and introduced fluids arising from the
jet grouting process, and normally flowing to the ground surface via the annulus of the jetting borehole
3.17
jet grouting parameters
parameters defined as:
— number and diameter of nozzle(s);
— pressure of the fluid(s);
— flow rate of the fluid(s);
— pressure and flow of the air (if used);
— grout or fluid composition;
— rotation speed of the jet grouting string;
— rate of withdrawal or insertion of the jet grouting string.
3.18
prejetting or precutting (multiple-phase jet grouting)
method in which the jet grouting of an element is preceeded by a preliminary phase of hydraulic
disaggregation
3.19
jet grouted material
material which constitutes the body of a jet grouted element
3.20
reinforced jet grouting
jet grouted columns reinforced by steel or other high strength material
3.21
grout
pumpable material (suspension, solution, emulsion) composed of water, binder and additives, that is
used as high energy fluid or cementing and which develops strength, e.g. measured as unconfined
compressive strength, over time
3.22
hydraulic binder
cement or similar product used in aqueous suspensions to produce grout
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3.23
jet pile
element where the cavity created by jetting is filled with concrete through a separate tremie pipe
replacing the materials contained in the cavity
3.24
sample quality class
classification of the samples extracted from the jet grouted element according to their surface,
structure, amount of irregularities and composure
3.25
equivalent zone
ground zone comprising one or several layers, clearly distinguished from the neighbour zones by a
range of properties relevant for jet grouting application
4 Information needed for the execution of the work
4.1 General
4.1.1 Prior to the execution of the work, all necessary information shall be provided.
4.1.2 This information shall include:
— any legal or statutory restrictions;
— the location of acceptable main grid lines for setting out element positions;
— the locations and conditions of structures, roads, services, etc. adjacent to the work, including any
necessary surveys;
— a suitable quality management system, including supervision, monitoring and testing.
4.1.3 The information regarding the site conditions shall cover, where relevant:
— the geometry of the site (boundary conditions, topography, access, slopes, headroom restrictions,
etc.);
— available space for storage, treatment and/or disposal of spoil;
— the existing underground structures, services, known contaminations, and archaeological
constraints; potential presence of unexploded ordnance and its location;
— the environmental restrictions, including noise, vibration, pollution;
— the future or ongoing activities such as dewatering, tunnelling, deep excavations.
4.2 Specific requirements
4.2.1 The specific requirements shall cover, where relevant:
— execution specifications
— previous use of the site;
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— adjacent foundations (types, loads and geometry);
— geotechnical information and data as specified in Clause 5;
— presence of any obstructions in the ground (old masonry, anchors, concrete, blocks and boulders,
etc.);
— certificate or written confirmation of removal of all unexploded ordnance;
— presence of headroom restrictions;
— presence of archaeological remains;
— presence of natural and/or man-made cavities (mines, etc.);
— presence of polluted ground and type, extent and degree of pollution;
— any specific requirements for the jet grouting works, in particular those pertaining to tolerances,
quality of materials and methods and frequency of testing;
— where available, previous experience with jet grouting or other grouting works on or adjacent to
the site;
— proposed adjacent enabling or advance works such as underpinning, pre-treatment of soil,
dewatering;
— the extent and type of instrumentation and monitoring required for potentially affected structures
— the degree of water tightness required;
— the required properties of the material between the jet grouting elements in the case of jet grouting
walls.
4.2.2 Necessity, extent, procedure and content for any survey on the conditions of structures, roads,
services, grid lines, etc. adjacent to the works area shall be established.
4.2.3 The survey shall be carried out and be available prior to the commencement of the works and
its conclusions shall be used to define the threshold values for any movement which may affect adjacent
structures by the works area constructions.
4.2.4 Any additional or deviating requirements falling within the scope of this standard shall be
established and agreed before the commencement of the works and the quality control system shall be
suitably amended.
NOTE Such additional or deviating requirements can be:
— reduced or increased geometrical construction deviations;
— application of different or varying grouting materials;
— special anchorage or connection of jet grouting elements to underlying rock;
— reinforcement;
— cut-off levels;
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— extensive manual excavation.
5 Geotechnical investigation
5.1 General
5.1.1 The geotechnical investigation shall fulfil the requirements of EN 1997 (all parts).
5.1.2 The depth and the extent of the geotechnical investigation should be sufficient to identify all
ground formations and layers affected by the jet grouting works, to determine the relevant properties of
the ground and to determine the ground conditions.
5.1.3 Relevant experience of the execution of comparable foundation works under similar conditions
and/or in the vicinity of the site should be taken into account when determining the extent of site
investigation (reference to relevant experience is permitted if appropriate means of verification are
taken, e.g. by penetration, pressuremeter or other tests).
NOTE Guidance is given in EN 1997–2 on the depth, extent and number of drillings or test pits as well as the
contents of a site investigation.
5.1.4 The geotechnical investigation report shall be available, to allow for reliable design and
execution of the jet grouting works.
5.1.5 The sufficiency of the geotechnical investigation for the design and execution of the jet grouting
works shall be verified.
5.1.6 If the geotechnical investigations are not sufficient, a supplementary investigation shall be
conducted.
5.2 Specific Requirements
5.2.1 Particular attention shall be paid to the following aspects, which are relevant to the execution of
jet grouting:
— the ground level at any point of investigation or testing relative to the recognized national datum or
to a fixed reference chart datum;
— piezometric levels of all water-tables and permeability of the soils;
— presence of coarse, highly permeable soils or cavities (natural or artificial), which can cause sudden
losses of grout and instability of the borehole during jetting or which can cause a sudden drop of
fluid level and thus can require special measures;
— presence, strength and deformation characteristics of cohesive soils, such as clay or peat, which can
cause difficulties during jetting;
— presence of boulders or obstructions which can cause shadows during jetting and, an assessment of
their size and frequency, when applicable;
— presence, position, strength of hard rock or other hard materials which can cause difficulties during
drilling and may require the use of special tools;
— presence, extent and thickness of any strata that can be sensitive to water infiltration or additional
hydrostatic pressure caused by jetting;
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— underground strata where high ground-water velocities exist;
— detrimental chemistry of groundwater, soil and rock, and water temperatures if required;
— detrimental chemistry of waste materials;
— presence of pre-treated soil, which can have an adverse effect during jetting;
— mining beneath the site;
— site stability problems (slope stability for instance).
5.2.2 The piezometric levels of the various water-tables existing on the site shall be monitored
separately and over a sufficient period of time to estimate the highest piezometric levels which can
occur during jet grouting.
5.2.3 Particular attention shall be paid to artesian conditions.
5.2.4 The relative density, over-consolidation ratio and grain size distribution of the soils and rocks
shall be determined by laboratory tests and/or in situ tests over the full depth of the jet grouting
elements and to a certain depth below their base.
5.2.5 When jet grouting elements are required to reach rock, the level of the rock surface shall be
determined as well as its properties including the degree of weathering and the extent and direction of
fissuring.
6 Materials and products
6.1 General
6.1.1 The constituents shall meet the requirements set in the respective European Standards, the
provisions valid for the place of use and those given in the project specification.
6.1.2 The sources of supply for constituents shall be documented and shall not be changed without
prior notification.
6.2 Cement
6.2.1 Cement for jet grouting shall comply with EN 197-1.
6.2.2 The selection with respect to exposure classes shall comply with EN 206.
6.2.3 Hydraulic binders other than cement may be used when the required performance is proven by
tests or respective regulations, certificates or approvals.
6.2.4 The use of cement with high sulphate resistance (i.e. free of C3A-Tricalciumaluminate) shall
comply with the provisions valid in the place of use.
NOTE 1 They are used for instance in cool, wet environments with presence of sulphate (e.g. seawater
structures).
NOTE 2 Where a European Standard does not exist and where there are no local regulations, comparable
experience and/or specific studies are necessary.
6.2.5 Calcium aluminate cement shall not be used.
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NOTE 1 The use of CEM III cement type or the replacement of CEM I cement type by ground granulated blast
furnace slag can result in reduced permeability.
6.2.6 Type II addition including fly ash, silica fume (as defined in EN 206) and ground granulated
blast furnace slag may be used as cement replacement.
6.3 Water
Mixing water shall comply with EN 1008 and EN 206.
6.4 Bentonite
6.4.1 A distinction should be made between calcium bentonite, natural sodium bentonite and
activated bentonite, which is a sodium bentonite produced from natural calcium bentonite by ion
exchange.
NOTE 1 Bentonite is clay containing mainly the mineral montmorillonite.
6.4.2 Bentonite used in bentonite suspensions shall not contain harmful constituents in such
quantities as can be detrimental to reinforcement or strength of jet grouting elements.
6.4.3 The chemical and mineralogical composition of the bentonite shall be known.
6.5 Additions
The use of additions shall comply with EN 206.
6.6 Admixtures
Admixtures used shall comply with EN 206.
NOTE 1 The admixtures used for jet grouting can be:
— water reducing/plasticizing;
— high range water reducing/super-plasticizing; and
— anti-wash-out
— set retarding;
— set accelerators.
NOTE 2 Admixtures can be used:
— to minimize bleeding and segregation that might otherwise result from a high water content;
— to control the workability time of the grout.
6.7 Reinforcement
Where steel as reinforcement is used, the material shall comply with EN 1993-1-5.
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7 Considerations related to design
7.1 General
7.1.1 Jet grouting can be applied in either temporary or permanent works for different purposes:
— to create structura
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