3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply.
natural or man made material formed of solid particles, including certain rocks, used to construct engineered fill
generic term for reinforcing inclusions placed within fill
fill which is placed and compacted under controlled conditions
engineered fill incorporating discrete layers of soil reinforcement, generally placed horizontally, which are arranged between successive layers of fill during construction
reinforcement which enhances stability of the reinforced fill mass by mobilising the axial tensile strength of the fill reinforcement by soil interaction over its total length
NOTE It is typically in the form of a strip, sheet, rod, grid or mesh and is usually placed in discrete layers.
for the purpose of this European standard “geosynthetics” stands for “geotextiles and geotextile related products”
covering to the exposed face of a reinforced fill structure which retains the fill between layers of reinforcement and protects the fill against erosion
foundation of a reinforced fill structure is the total area of the surface upon which the lowest layer of reinforcement is installed
discrete facing unit
partial height facing unit used to construct incrementally a reinforced fill structure
full height facing unit
facing unit equal to the height of the face of the structure
hard facing unit
panel or block usually of precast concrete with intrinsically low vertical compressibility and high bending stiffness. (See C.2.1 for guidance)
deformable facing unit
preformed steel grid section, a preformed solid steel section or a rock filled gabion with intrinsically vertical compressibility and low bending stiffness. (See C.2.2 for guidance)
soft facing unit
soil fill encapsulated in a geogrid or a geotextile facing with no bending stiffness. (See C.2.3 for guidance)
assemblage of facing units used to produce a finished reinforced fill structure
rigid facing system
facing system with no capacity to accommodate vertical differential settlement between fill and facing. (See Annex C for guidance)
semi-flexible facing system
facing system with some capacity to accommodate differential settlement between fill and facing
flexible facing system
pliant, articulated, facing system with capacity to accommodate differential settlement between fill and facing
vegetative cover or infill used without facing units or as an adjunct to reinforced fill structures constructed using facing units
false facing added in front of the facing to improve the aesthetics of a finished reinforced fill structure
service life, in years, required by the design
structures with a design life of 1 - 5 years (Class 1)
structures with a design life of more than 5 years (Class 2 – 5)
4 Information needed for construction
4.1 Prior to commencement of any construction work all information necessary for the construction of the works in compliance with the design and contract documents shall be provided.
4.2 Information shall include definition of the reporting procedure to deal with unforeseen circumstances, or with any conditions revealed or considered during construction which appear to be worse than those assumed in the design.
4.3 Information shall include definition of the reporting procedure if an observational method of design is adopted or monitoring is required.
4.4 Notice of any restrictions such as any construction phasing required by the design, any restrictions on site access, any environmental restrictions or any statutory restrictions on the site shall be provided.
4.5 For works to be constructed to specified levels, co-ordinates and tolerances these shall be shown on plans, or in the specification, together with the positions, levels of and co-ordinates of fixed reference points at or near the works construction site.
4.6 When relevant a schedule of any testing and acceptance procedures for materials incorporated in the works shall be provided.
4.7 When samples of reinforcements are to be installed for the assessment of their long term degradation, or pull-out capacity, detailed instructions with regard to their location, identification and installation shall be provided.
4.8 To avoid damage to existing or proposed services the accurate location of all services such as electricity, telephone, water, gas, drains and sewers shall be ascertained.
4.9 If the site is subject to tidal working or flooding, cold climate conditions or allied restrictions, details of such restrictions shall be ascertained.
5 Geotechnical investigations
5.1 The extent of any site investigation shall be sufficient to allow determination of ground conditions at the site in accordance with the requirements of EN 1997-1 and to enable construction of the works in compliance with the contract documents and design.
5.2 Geotechnical, hydrogeological and hydrological information should be provided to enable the constructor to design any temporary works or accesses needed for construction (e.g. earthworks, embankments, stabilization of excavations or cuttings near the structure, construction of cofferdams.)
5.3 Relevant geotechnical investigation shall be provided to determine the properties of the fill material related to:
- workability, in accordance with 6.2.2;
- aggressiveness against the reinforcements or the facing, in accordance with 6.2.8;
- internal friction and cohesion, in accordance with 6.2.10.
5.4 A geotechnical investigation, in accordance with 18.104.22.168 to 22.214.171.124, shall be provided, when relevant, to determine the aggressiveness of:
- foundation material which can be in contact with the reinforcement or facing;
- ground water which can soak the selected fill and affect its own aggressiveness.