Execution of special geotechnical works - Deep mixing
This document specifies general principles for the execution, testing, supervision and monitoring of deep mixing works carried out by two different methods: dry mixing and wet mixing.
Deep mixing considered in this document is limited to methods, which involve:
a) mixing by rotating mechanical mixing tools (see Annex A, Figure A.1) where the lateral support provided to the surrounding soil is not removed;
b) treatment of the soil to a minimum depth of 3 m;
c) different shapes and configurations, consisting of either single columns, panels, grids, blocks, walls or any combination of more than one single column, overlapping or not (see Annex A, Figures A.8 to A.12);
d) treatment of natural soil, fill, waste deposits and slurries, etc.;
e) other ground improvement methods using similar techniques exist (see A.3.5).
Guidance on practical aspects of deep mixing, such as execution procedures and equipment, is given in Annex A. Main applications are exemplified in Annex A, Figure A.14. Methods of testing, specification and assessment of design parameters, which are affected by execution, are presented in Annex B.
Ausführung von besonderen geotechnischen Arbeiten (Spezialtiefbau) - Tiefreichende Bodenstabilisierung
Dieses Dokument legt die allgemeinen Grundlagen für die Ausführung, Kontrolle, Überwachung und Aufzeich-nung der tiefreichenden Bodenstabilisierung fest, wobei zwischen zwei verschiedenen Verfahren unterschieden wird: das Trockenmischverfahren und das Nassmischverfahren.
Die tiefreichende Bodenstabilisierung ist nach diesem Dokument auf Verfahren mit folgenden Eigenschaften beschränkt:
a) Mischung durch rotierende mechanische Mischwerkzeuge (siehe Anhang A, Bild A.1), wobei die horizontale Stützung durch den umgebenden Boden nicht beseitigt wird;
b) Behandlung des Bodens bis in eine Tiefe von mindestens 3 m;
c) unterschiedliche Geometrien und Anordnungen, bestehend aus einzelnen Säulen, Mehrfachelementen, Rastern, Blöcken, Wänden oder Kombinationen von mehr als einer Einzelsäule, überschnitten oder allein stehend (siehe Anhang A, Bilder A.8 bis A.12);
d) Behandlung von gewachsenem Boden, Auffüllung, Müllablagerungen und Schlämmen usw.;
e) andere Bodenverbesserungsverfahren, die ähnliche Techniken verwenden (siehe A.3.5).
Hinweise zu praktischen Aspekten der tiefreichenden Bodenstabilisierung betreffend Ausführungstechniken und Ausrüstung werden in Anhang A gegeben. Hauptanwendungen werden in Anhang A, Bild A.14 veranschaulicht. Prüfverfahren und die Beschreibung und Festlegung von Bemessungsparametern werden in Anhang B vorgestellt, soweit sie durch die Ausführung beeinflusst werden.
Exécution des travaux géotechniques spéciaux - Colonnes de sol traité
La présente Norme européenne établit les principes généraux relatifs à l'exécution, aux essais de contrôle, à
la surveillance et au suivi des travaux de colonnes de sol traité réalisés selon la technique de malaxage par
voie sèche ou selon la technique de malaxage par voie humide.
Les colonnes de sol traité, concernées par la présente norme, sont celles qui s�inscrivent dans le cadre défini
a) le mélange est effectué au moyen d'outils rotatifs mécanique de malaxage (voir l'Annexe A, Figure A.1), le
sol environnant latéral étant constamment maintenu pendant l�opération ;
b) le traitement du sol est réalisé sur une hauteur minimale de 3 m ;
c) la réalisation de différentes formes et configurations, comprenant des colonnes simples, des panneaux,
des grilles, des massifs, des parois ou toute autre combinaison d'au moins deux colonnes simples, se
recoupant ou non (voir l'Annexe A, Figures A.8 à A.12) ;
d) le traitement de sol naturel, de remblai, de dépôts d�ordures et de déchets, etc. ;
e) il existe d�autres méthodes d'amélioration du sol utilisant des techniques similaires (voir A.3.5).
Des informations pratiques relatives à la réalisation des colonnes de sol traité, comme les procédures
d�exécution et les matériels, sont données en Annexe A. Les méthodes d'essais et d'évaluation des
paramètres de conception, qui intéressent l'exécution, sont présentées en Annexe B.
Izvedba posebnih geotehničnih del – Globinsko mešanje
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Execution of special geotechnical works - Deep mixingExécution des travaux géotechniques spéciaux - Colonnes de sol traitéAusführung von besonderen geotechnischen Arbeiten (Spezialtiefbau) - Tiefreichende Bodenstabilisierung93.020Zemeljska dela. Izkopavanja. Gradnja temeljev. Dela pod zemljoEarthworks. Excavations. Foundation construction. Underground worksICS:SIST EN 14679:2005enTa slovenski standard je istoveten z:EN 14679:200501-oktober-2005SIST EN 14679:2005SLOVENSKI
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 14679April 2005ICS 93.020English versionExecution of special geotechnical works - Deep mixingExécution des travaux géotechniques spéciaux - Colonnesde sol traitéAusführung von besonderen geotechnischen Arbeiten(Spezialtiefbau) - Tiefreichende BodenstabilisierungThis European Standard was approved by CEN on 28 February 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.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 STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2005 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14679:2005: E
EN 14679:2005 (E) 2 Contents Page 1 Scope.5 2 Normative references.5 3 Terms and definitions.6 4 Information needed for the execution of the work.8 4.1 General.8 4.2 Particular requirements.9 5 Geotechnical investigation.9 5.1 General.9 5.2 Specific information.9 6 Materials and products.10 6.1 General.10 6.2 Special considerations.11 7 Considerations related to design.11 7.1 General.11 7.2 Additional design considerations.12 7.3 Selection of the binder and the additives.12 7.4 Laboratory and in-situ mixing and treatment tests.12 7.5 Design statement.13 8 Execution.14 8.1 Method statement.14 8.2 Preparation of the site.14 8.3 Field trials.15 8.4 Execution tolerances.15 8.4.1 General.15 8.5 Quality control and quality assurance.15 8.6 Deep mixing.15 8.6.1 General.15 8.6.2 Dry mixing.16 8.6.3 Wet mixing.16 8.7 Installation of structural reinforcement.17 9 Supervision, testing and monitoring.17 9.1 General.17 9.2 Supervision.18 9.3 Testing.18 9.4 Monitoring.18 9.5 Performance of the treated soil.19 9.6 Other aspects.19 10 Records.19 10.1 Records during construction.19 10.2 Records at the completion of the work.20 11 Special requirements.20 11.1 General.20 11.2 Safety.20 11.3 Environmental protection.20 11.4 Impact on adjacent structures.21 Annex A (informative)
Practical aspects of deep mixing.22
EN 14679:2005 (E) 3 A.1 Introduction.22 A.2 Fields of application.22 A.3 Execution.22 A.3.1 General.22 A.3.2 Dry mixing.24 A.3.3 Wet mixing.28 A.3.4 Patterns of installation.31 A.3.5 Hybrid methods.34 A.4 Construction considerations.36 Annex B (informative)
Aspects of design.38 B.1 General.38 B.1.1 Scope.38 B.1.2 Application.38 B.2 Design principles.39 B.3 Execution process of deep mixing.40 B.4 Choice of binder.41 B.5 Testing.41 B.5.1 General.41 B.5.2 Laboratory testing.41 B.5.3 Field testing.43 B.6 Correlation of various properties of treated soil.44 B.6.1 Field strength and laboratory strength.44 B.6.2 Correlation between mechanical characteristics and unconfined compressive strength.46 B.7 Aspects of design.46 B.7.1 Stability.46 B.7.2 Settlement.49 B.7.3 Confinement.49 Annex C (informative)
Degree of obligation of the provision.50
EN 14679:2005 (E) 4 Foreword This document (EN 14679:2005) 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 October 2005, and conflicting national standards shall be withdrawn at the latest by October 2005. The document has been prepared to stand alongside EN 1997-1 and prEN 1997-2. This document expands on design only where necessary, but provides full coverage of the construction and supervision requirements. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: 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.
EN 14679:2005 (E) 5 1 Scope This document specifies general principles for the execution, testing, supervision and monitoring of deep mixing works carried out by two different methods: dry mixing and wet mixing. Deep mixing considered in this document is limited to methods, which involve: a) mixing by rotating mechanical mixing tools (see Annex A, Figure A.1) where the lateral support provided to the surrounding soil is not removed; b) treatment of the soil to a minimum depth of 3 m; c) different shapes and configurations, consisting of either single columns, panels, grids, blocks, walls or any combination of more than one single column, overlapping or not (see Annex A, Figures A.8 to A.12); d) treatment of natural soil, fill, waste deposits and slurries, etc.; e) other ground improvement methods using similar techniques exist (see A.3.5). Guidance on practical aspects of deep mixing, such as execution procedures and equipment, is given in Annex A. Main applications are exemplified in Annex A, Figure A.14. Methods of testing, specification and assessment of design parameters, which are affected by execution, are presented in Annex B. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 196-1, Methods of testing cement — Part 1: Determination of strength EN 196-2, Methods of testing cement — Part 2: Chemical analysis of cement EN 196-3, Methods of testing cement — Part 3: Determination of setting time and soundness EN 196-4, Methods of testing cement — Part 4: Quality determination of constituents EN 196-5, Methods of testing cement — Part 5: Pozzolanicity tests for pozzolanic cement EN 196-6, Methods of testing cement — Part 6: Determination of fineness EN 196-7, Methods of testing cement — Part 7: Methods of taking and preparing samples of cement EN 196-8, Methods of testing cement — Part 8: Heat of hydration — Solution method EN 196-21, Methods of testing cement — Part 21: Determination of the chloride, carbon dioxide and alkali content of cement EN 197-1:2000, Cement — Part 1: Composition, specification and conformity criteria for common cements EN 197-2:2000, Cement — Part 2: Conformity evaluation EN 451, Methods of testing fly ash EN 459-1, Building lime — Part 1: Definitions, specifications and conformity criteria
EN 14679:2005 (E) 6 EN 459-2, Building lime — Part 2: Test methods EN 791:1995, Drill rigs — Safety EN 1997-1, Eurocode 7: Geotechnical design — Part 1: General rules prEN 1997-2, Eurocode 7 — Geotechnical design — Part 2: Ground investigation and testing EN 12716, Execution of special geotechnical works — Jet grouting ENV 1991, Eurocode 1: Actions on structures ENV 10080, Steel for reinforcement of concrete, weldable ribbed reinforcing steel B 500 — Technical delivery conditions for bars, coils and welded fabric EN ISO 14688-1, Geotechnical investigation and testing — Identification and classification of soil — Part 1: Identification and description (ISO 14688-1:2002) EN ISO 14688-2, Geotechnical investigation and testing — Identification and classification of soil — Part 2:
Principles for a classification (ISO 14688-2:2004) EN ISO 14689-1, Geotechnical investigation and testing — Identification and classification of rock — Part 1: Identification and description (ISO 14689-1:2003). 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 admixture fr: additif, addition de: Zusatzmittel dispersant, fluidifier, retarding agent 3.2 binder fr: liant de: Bindemittel chemically reactive materials (lime, cement, gypsum, blast furnace slag, fly ash, etc.) 3.3 binder content fr: teneur pondéral en liant de: Bindemittelgehalt weight of dry binder introduced per unit volume of soil to be treated 3.4 binder factor fr: dosage volumique de liant de: Bindemittelfaktor ratio of the weight of dry binder introduced to the dry weight of the soil to be treated 3.5 blade rotation number fr: nombre de rotation d'aile de: Flügelumdrehungszahl total number of mixing blade rotations per m of shaft movement.
EN 14679:2005 (E) 7 3.6 column fr: colonne de: Säule pillar of treated soil manufactured in situ by a single installation process using a mixing tool. The mixing tool and the execution process govern the shape and size of the cross section of a column 3.7 dry mixing fr: malaxage par voie sèche de: Trockenmischverfahren process consisting of mechanical disaggregation of the soil in situ and its mixing with binders with or without fillers and admixtures in dry powder form 3.8 filler fr: fines inerte, charge inerte de: Füller non-reacting material (sand, limestone powder etc.) 3.9 mixing energy fr: energie de malaxage de: Mischungsenergie resources used for operating machinery 3.10 mixing process fr: processus de malaxage de: Mischvorgang involves mechanical disaggregation of the soil structure, dispersion of binders and fillers in the soil 3.11 mixing tool fr: outil de malaxage de: Mischwerkzeug tool used to disaggregate the soil, distribute and mix the binder with the soil, consisting of one or several rotating units equipped with several blades, arms, paddles with/without continuous or discontinuous flight augers (see Annex A) 3.12 penetration (downstroke) fr: enfoncement (descente de l’outillage) de: Abbohrvorgang stage/phase of mixing process cycle, in which the mixing tool is delivered to the appropriate depth and initial mixing and fluidisation of the soil take place 3.13 penetration or retrieval speed fr: vitesse d’enfoncement ou de remontée de: Abbohr- bzw. Ziehgeschwindigkeit vertical movement per unit time of the mixing tool during penetration or retrieval 3.14 penetration or retrieval rate fr: vitesse d’enfoncement ou de remontée par tour de: Abbohr- bzw. Ziehrate vertical movement of the mixing tool per revolution of the rotating unit(s) during penetration or retrieval 3.15 retrieval (upstroke) fr: remontée (montée de l’outillage) de: Ziehvorgang stage/phase of mixing process cycle, in which the final mixing and retrieval of the mixing tool take place
EN 14679:2005 (E) 8 3.16 restroke fr: re-malaxage de: wiederholter Mischvorgang restroke is an additional penetration and retrieval cycle of the mixing tool to increase the binder content and/or the column homogeneity 3.17 rotation speed fr: vitesse de rotation de: Umdrehungsgeschwindigkeit number of revolutions of the rotating unit(s) of the mixing tool per unit time 3.18 stroke fr: malaxage de: Mischvorgang one complete cycle of the mixing process 3.19 volume ratio fr: teneur volumique en coulis de: Volumenverhältnis ratio of the volume of slurry injected (in wet mixing) to the volume of soil to be treated 3.20 water/binder ratio fr: rapport eau/liant de: Wasser-/Bindemittel-Verhältnis weight of water added to the dry binder divided by the weight of the dry binder 3.21 wet mixing fr: malaxage par voie humide de: Nassmischverfahren process consisting of mechanical disaggregation of the soil in situ and its mixing with a slurry consisting of water, binders with or without fillers and admixtures 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 should include: a) any legal or statutory restrictions; b) the location of main grid lines for setting out; c) the conditions of structures, roads, services, etc. adjacent to the work; d) a suitable quality management system, including supervision, monitoring and testing. 4.1.3 The information regarding the site conditions shall cover, where relevant: a) the geometry of the site (boundary conditions, topography, access, slopes, headroom restrictions etc); b) the existing underground structures, services, known contamination, and archaeological constraints; c) the environmental restrictions, including noise, vibration, pollution; d) future or ongoing construction activities, such as dewatering, tunnelling, deep excavations.
EN 14679:2005 (E) 9 4.2 Particular requirements 4.2.1 The following information shall also be provided: a) previous experience of deep mixing or special geotechnical works adjacent to the site, including the results of field tests to confirm the design; b) underground contamination or hazards that can affect the execution method, the work safety or the discharge of excavation material from the site. 4.2.2 The following instructions shall be given: a) reporting procedure for unforeseen circumstances, or conditions revealed that appear to be different from those assumed in the design; b) reporting procedure, if an observational method of design is adopted; c) notice of any restrictions such as construction phasing required in the design; d) a schedule of any testing and acceptance procedures for materials incorporated in the works. 4.2.3 Any additional or deviating requirements falling within the permission clauses given in this document shall be established and agreed upon before the commencement of the works. 5 Geotechnical investigation 5.1 General 5.1.1 The depth and the extent of any investigations shall be sufficient to allow determination of the ground conditions in accordance with the requirements of EN 1997-1. 5.1.2 Laboratory and field investigations shall comply with prEN 1997-2 and the relevant European Standard EN 196-1 to -8, EN 196-21, EN 197-1 and -2, EN 451, EN 459-1 and -2, ENV 10080, EN 12716,
EN 791 and EN ISO 14689-1). 5.1.3 Relevant experience of the execution of comparable deep mixing works under similar conditions in the vicinity of the site shall be taken into account when determining the extent of the site investigation. 5.1.4 The site investigation report shall be made available together with all relevant data known to affect the choice of method. 5.1.5 Boreholes or trial pits shall be suitably sealed not to affect groundwater movement and/or subsequent deep-mixed column construction and performance. 5.2 Specific information 5.2.1 Identification and classification of soil shall comply with EN ISO 14688-1 and EN ISO 14688-2. 5.2.2 Apart from the general geological description and the details listed in EN 1997-1, the site investigation report shall contain the following information regarding ground conditions for the execution of deep mixing: a) the composition, lateral extent, thickness and firmness of the surface stratum, tree roots, fill, etc.; b) presence of cobbles or boulders, cemented layers or underlying rock that can cause difficulties for the execution or could require special methods or tools;
EN 14679:2005 (E) 10 c) presence of swelling soil (montmorillonite); d) cavities, voids or fissures; e) piezometric levels of groundwater, its variation and possible artesian pressure; 5.2.3 When relevant, the following additional information should be provided: 220.127.116.11 Physical and state characteristics: a) consistency limits; b) classification; c) density; d) grain size distribution; e) mineralogy; f) natural water content; g) organic content. 18.104.22.168 Mechanical characteristics: a) deformation and consolidation; b) strength (shear, compressive and tensile); c) permeability. 22.214.171.124 Environmental, chemical and biological characteristics: a) groundwater quality (e.g. contamination, aggressiveness, chemistry, pH- value, type and concentration of ions and metals (reference measurements); b) contamination test data; c) leaching tests. 5.2.4 The ground level and location at any point of investigation or testing should be established relative to the recognised national datum or to a fixed reference point. 6 Materials and products 6.1 General 6.1.1 Construction of deep mixing involves the addition of a binder and, if needed, one or more of the following components to the soil: a) admixture; b) water; c) filler;
EN 14679:2005 (E) 11 d) structural reinforcement. 6.1.2 All materials and products for incorporation in deep mixing shall be in accordance with the relevant European Standards. Where the respective European Standards are not available, the use of materials and products shall be in accordance with the national standards and/or guidance. 6.1.3 All materials and products used shall comply with local environmental regulations. 6.1.4 All materials and products used shall comply with the design specifications. 6.1.5 Appropriate tests shall be provided in order to ensure compliance with the design specifications for materials not covered by existing standards. 6.1.6 The sources of supply materials shall be documented and shall not be changed without prior notification. 6.2 Special considerations 6.2.1 Water from other sources than recognised potable water shall be tested to determine whether or not it is suitable for the intended use. 6.2.2 Environmentally significant traces of chemical substances in materials and products may be present as normally occurring impurity, and their environmental impact may need to be assessed. 7 Considerations related to design 7.1 General 7.1.1 The in-situ strength of columns is influenced by several factors, such as properties of the soil to be treated, mixing condition, mixing tool and mixing process, curing condition, type and amount of binder, ground conditions, etc. Therefore it can be difficult to estimate the field strength accurately at the design stage. It is important to estimate and verify the field strength in several stages by laboratory mixing tests, accumulated experience, field trials and verification tests. The design should be modified if the requirements cannot be fulfilled. 7.1.2 The execution of deep mixing projects involves geotechnical design in several phases and can be an iterative process. The objective of the design is to produce technical documents, which enable works to be constructed with regard to safety, serviceability, economy and durability, taking into account the expected service life. It is recommended that the parties responsible for the design should be involved also during the construction. 7.1.3 The geotechnical design of deep mixing projects shall be based on ENV 1991, EN 1997-1 and prEN 1997-2. The informative Annex B summarises important parameters, which affect overall stability and settlement of the treated ground. 7.1.4 Reference to relevant experience is permitted if appropriate verification has been undertaken (e.g. by penetration tests, pressuremeter tests or other tests). 7.1.5 A method statement shall be prepared, which details the deep mixing works. As a minimum requirement, the method statement shall detail the location and the purpose of the works, the required design life, possible restrictions during the construction phase and any hazards associated with the execution of the works. 7.1.6 When there is some latitude in the selection of materials, the method statement shall emphasise the particular requirements, which can influence the final selection.
EN 14679:2005 (E) 12 7.1.7 Preliminary design can be based on tests of laboratory mixed samples and comparable experience, taking into account the difference in characteristics between laboratory mixed samples and treated soil in-situ. NOTE For guidance, reference is made to Annex B. 7.1.8 Testing may not be sufficient to verify the adequacy of the treatment. Appropriate supervision, monitoring and rec