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of an identical text or by endorsement, at the latest by October 2005, and conflicting national standards shall be withdrawn at the latest by October 2005.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.
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, A.9, A10, A11 and A.12);
- d) treatment of natural soil, fill, waste deposits and slurries, etc.
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 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.
fr: additif, addition
dispersant, fluidifier, retarding agent
chemically reactive materials (lime, cement, gypsum, blast furnace slag, fly ash, etc.)
fr: dosage en liant
weight of dry binder introduced per unit volume of soil to be treated
fr: teneur en liant
ratio of the weight of dry binder introduced to the dry weight of the soil to be treated
blade rotation number
fr: indice de malaxage
total number of mixing blade rotations per m of shaft movement.
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
fr: malaxage par voie sèche
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
fr: fines inerte, charge inerte
non-reacting material (sand, limestone powder etc.)
fr: energie de malaxage
resources used for operating machinery
fr: procédé de malaxage
involves mechanical disaggregation of the soil structure, dispersion of binders and fillers in the soil
fr: outil de malaxage
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)
fr: descente (de l’outillage)
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
penetration or retrieval speed
fr: vitesse de descente ou de remontée
de: Abbohr- bzw. Ziehgeschwindigkeit
vertical movement per unit time of the mixing tool during penetration or retrieval
penetration or retrieval rate
fr: vitesse de descente 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
fr: remontée (montée de l’outillage)
stage/phase of mixing process cycle, in which the final mixing and retrieval of the mixing tool take place
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
fr: vitesse de rotation
number of revolutions of the rotating unit(s) of the mixing tool per unit time
one complete cycle of the mixing process
fr: teneur volumique en coulis
ratio of the volume of slurry injected (in wet mixing) to the volume of soil to be treated
fr: rapport eau/liant
weight of water added to the dry binder divided by the weight of the dry binder
fr: malaxage par voie humide
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