CEN/TC 288 - Execution of special geotechnical works

This document specifies requirements, recommendations and information concerning the execution of permanent or temporary sheet pile wall, combined pile walls, high modulus wall structures and the handling of equipment and materials.
This document does not give requirements and recommendations for the installation of specific parts of the structure such as ground anchorages, displacement piles and micropiles which are covered by other documents.
This document is applicable to steel sheet pile walls, combined walls, high modulus walls, and synthetic sheet pile walls (composite), precast concrete and timber sheet pile walls. Tubular piles included in combined walls and high modulus walls can be filled with concrete.
Composite structures such as Berliner walls and sheet pile walls in combination with shotcrete, are not covered by this document.

This document is applicable to the execution, testing and monitoring of geotechnical grouting work.
Grouting for geotechnical purposes (geotechnical grouting) is a process in which the remote placement of a pumpable material in the ground is indirectly controlled by adjusting its rheological characteristics and by the manipulation of the placement parameters (pressure, volume and the flow rate).
The following principles and methods of geotechnical grouting are covered by this document:
-   displacement grouting (compaction and compensation grouting);
-   grouting without displacement of the host material (permeation, fissure/contact grouting, bulk filling).
Figure 1 illustrates the various injection methods associated with these two principles.
NOTE   The term consolidation grouting is sometimes used to emphasize an improvement in the strength or deformation characteristics of a soil or rock mass, with the aim that it does not undergo any unacceptable deformation. The term compensation grouting is used when the objective of grouting is to concurrently compensate for ground loss.
The principal objectives of geotechnical grouting are:
-   the modification of the hydraulic/hydrogeological characteristics of the ground;
-   the modification of the mechanical properties of the ground;
-   the filling of natural cavities, mine workings, voids adjacent to structures;
-   inducing displacement to compensate for ground loss or to stabilize and lift footings, slabs and pavements.
Specialized grouting activities, generally associated with structural and/or emergency works, are not covered by this document.
The execution, testing and monitoring of jet grouting work is not covered by this document and is covered by EN 12716.

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.

This European Standard establishes general principles for the execution of diaphragm walls as either retaining walls or cut-off walls.
NOTE 1   This standard covers only structures constructed in a trench excavated with a support fluid or in dry conditions, where soil is removed and replaced by concrete or slurry and with wall thickness B ≥ 40 cm.
NOTE 2   Diaphragm walls can be permanent or temporary structures.
NOTE 3   The following types of structure are considered:
a)   retaining walls: usually constructed to support the sides of an excavation in the ground. They include:
1)   cast in situ concrete diaphragm walls;
2)   precast concrete diaphragm walls;
3)   reinforced slurry walls;
b)   cut-off walls: usually constructed to prevent migration of groundwater, clear or polluted, or of other contaminants present in the ground. They include:
1)   slurry walls (possibly with membranes or sheet piles);
2)   plastic concrete walls.
NOTE 4   Walls formed shallow vertical trenches (typically excavations with a ratio of depth over thickness D/B < 5 or D < 5 m) are not covered by this standard.

1.1   This European Standard establishes general principles for the execution of bored piles (see 3.2).
NOTE 1   This standard covers piles or barrettes which are formed in the ground by excavation and are structural members used to transfer actions and/or limit deformations.
NOTE 2   This standard covers piles with circular cross-section (see Figures 1 and A.1a)) and barrettes (see 3.3) with rectangular, T or L or any other similar cross-section (see Figure 2) concreted in a single operation.
NOTE 3   In the standard the term pile is used for circular cross-section structure and the term barrette for other shapes. Both are bored piles.
1.2    This European Standard applies to bored piles (see Figure 3) with:
-   uniform cross-section (straight shaft);
-   telescopically changing shaft dimensions;
-   excavated base enlargements; or
-   excavated shaft enlargements.
NOTE    The shape of a pile base and of an enlargement depends on the tool used for the excavation.
1.3    This European Standard applies (see Note) to:
-   bored piles with a depth to width ratio  5;
-   piles (see Figures 1 and 3) with a shaft diameter 0,3 m  D  3,0 m;
-   barrettes (see Figure 2) with the least dimension Wi  0,4 m, a ratio LBiB / Wi between its largest and its least dimensions  6 and a cross-sectional area A  15 m²;
-   piles with circular precast elements used as structural member (see Figure 7) with a least dimension DP  0,3 m;
-   barrettes with rectangular precast elements used as structural member with a least dimension WP  0,3 m.
NOTE   The standard covers a large range of diameters. For small diameter bored piles less than 450 mm, the general specification can be adapted to cater for the lack of space (e.g. minimum bars number and spacing).
1.4    This European Standard applies to piles with the following rake (see Figure 4):
-   n  4 (  76°);
-   n  3 (  72°) for permanently cased piles.
(...)

1.1   This European Standard establishes general principles for the execution of micropiles.
They are for drilled piles constructed using a drilling tool with a diameter less than 300 mm.
NOTE 1   This European Standard is not applicable to driven piles, the execution of which is governed by EN 12699.
NOTE 2   For a definition of shaft diameter see 3.3.
1.2   Micropiles are structural members to transfer actions to the ground and can contain bearing elements to transfer directly or indirectly loads and or to limit deformations. For examples of micropiles see Figure 1, Figure 2 and Figure 3. Their shaft and base resistance can be improved (mostly by grouting) and they can be constructed with (see Figure 4):
-   uniform cross section (straight shaft); or
-   telescopically changing shaft dimensions;
-   shaft enlargements; and/or
-   base enlargement.
1.3   Other than practical considerations, there are no limitations regarding, length, inclination (definition of inclination, see Figure 5), slenderness ratio or shaft and base enlargements.
1.4   The provisions of this European Standard apply to (see Figure 6):
-   single micropiles;
-   micropile groups;
-   reticulated micropiles;
-   micropile walls.
1.5   The material of micropiles covered by this European Standard can be:
-   steel or other reinforcement materials;
-   grout, mortar or concrete;
-   a combination of above.
1.6   Micropiles can be used for:
-   working under restricted access and/or headroom conditions;
-   foundations of new structures (particularly in very heterogeneous soil or rock formations);
-   reinforcing or strengthening of existing structures to increase the capacity to transfer load to depth with acceptable load settlement characteristics, e.g. underpinning works;
-   reducing settlements and/or displacements;
-   forming a retaining wall;
-   reinforcing of soil to form a bearing and/or retaining structure;
-   improving slope stability;
-   securing against uplift;
-   other applications where micropile techniques are appropriate.
1.7   Deep mixing columns according to EN 14679 are not included in this European Standard. Columns constructed by jet grouting are covered by EN 12716. Ground anchors are covered by EN 1537.

1.1   This European Standard establishes general principles for the execution of displacement piles, that means piles which are installed in the ground without excavation or removal of material from the ground except for limiting heave and/or limiting vibration as well as removal of obstructions or to assist penetration.
Piles are driven into the ground using impact, vibration, pressing, screwing or a combination of these methods.
1.2   The material of displacement piles covered by this European Standard can be:
-   steel;
-   cast iron;
-   concrete, mortar;
-   timber;
-   grout;
-   combination of above.
1.3   This European Standard covers prefabricated, cast in situ, or a combination of these methods to form displacement piles of regular shape.
Examples are given in Figure A.2 and Figure A.3.
1.4   Displacement piles may be installed in soils enhanced by ground improvement techniques. The ground improvement can be executed before, at the same time or after installation of the piles.
1.5   Other than practical considerations there are for the purpose of this European Standard no limitations regarding cross section dimensions, shaft or base enlargements, length or rake.
1.6   The provisions of this European Standard apply to:
-   single piles;
-   pile groups;
-   concrete sheet piles.
1.7   Columns constructed by ground improvement techniques (such as mixed in situ columns, jet grouting, compaction grouting, vibro flotation, stone columns) are not covered by this European Standard. Bored piles are covered in EN 1536. Steel and timber sheet pile walls are covered in EN 12063. Micropiles are covered in EN 14199.

1.1   This European Standard covers ground anchors grouted into the ground which are stressed and tested. They can be used for permanent or temporary applications.
NOTE   For the purpose of this standard the term ‘anchor(s)’ refers to ‘ground anchor(s)’.
1.2   The anchors are designed in accordance with EN 1997-1 and are tested in accordance with prEN ISO 22477 5.
1.3   Typical bond and compression type anchors are shown in Figure 1 and Figure 2.
1.4   The term "ground" is taken to encompass soil, rock and fill already in place or existing prior to the execution of the construction work.
1.5   The planning and design of ground anchors calls for experience and knowledge in this specialised field.
1.6   The installation and testing phases require skilled, qualified labour and supervision.
1.7   This standard cannot replace the knowledge of specialist personnel and the expertise of experienced contractors required to apply this standard.
1.8   This standard does not address systems such as tension piles, screw anchors, mechanical anchors, soil nails, dead-man anchors or expander anchors as these do not fulfil the requirements of this standard.

1.1   This European Standard establishes general principles for the execution, testing, supervision and monitoring of soil nailing.
1.2   Soil nailing is a construction technique, used to enhance/maintain the stability of a soil mass by installation of reinforcing elements (soil nails). Typical examples of soil nailing are given in Annex A.
1.3   The scope of soil nailing applications considered in this European Standard includes the installation and testing of soil nails and associated operations, required when stabilising existing and newly cut slopes and faces in soil, existing earth retaining structures, embankments, existing tunnels and the excavated facing of new tunnels in soil.
1.4   Soil nailing may be used to form part of a hybrid construction. This European Standard is relevant only to the soil nailing aspect of such constructions.
1.5   Techniques, such as reinforcement of ground by vertical inclusions (sheet piles, bored or driven piles, or other elements) and stabilisation with rock bolts, prestressed ground anchors or tensions piles are not covered by this European Standard.
1.6   Guidance on practical aspects of soil nailing and aspects on design, durability and testing is given in informative Annexes A, B and C, respectively.

This European Standard establishes general principles for the execution, testing, supervision and monitoring of vertical drain projects.
This European Standard includes the application of prefabricated vertical drains and sand drains and deals with requirements to be placed on design, drain material and installation methods. This European Standard applies to the improvement of low-permeability, highly compressible soils by vertical drainage and preloading. Information regarding loading (embankment, vacuum or ground water lowering) and preloading is given in informative Annexes A and B.
Vertical drainage is used both in on land and in marine constructions for the following purposes:
   (pre-)consolidation and reduction of post-construction settlements;
   speeding up the consolidation process by decreasing the path lengths for pore water dissipation;
   increase of stability (by increasing effective stresses in the soil);
   groundwater lowering;
   mitigation of liquefaction effects.
In each case there is an overall treatment of the soil (the volume of the drains is small in relation to the soil volume treated).
This European Standard does not include soil improvement by means of wells, gravel and stone columns, large-diameter geotextile enclosed columns or reinforcing elements.
Vertical drainage can also be combined with other foundation or ground improvement methods, e.g. electro osmosis, piles and compacted sand piles, dynamic compaction and deep mixing.
Guidance on practical aspects of vertical drainage, such as investigation of drain properties, execution procedures and equipment, is given in Annex A. Investigation of soil characteristics and assessment of design parameters, which are affected by drain properties and execution, are presented in Annex B.

TC - Modification to 6.3.2.2 and Table A.1

1.1   This European Standard establishes general principles for the construction of reinforced fill.
1.2   This European Standard covers engineered fills that are reinforced by the inclusion of horizontal or sub-horizontal reinforcement placed between layers of fill during construction.
1.3   The scope of reinforced fill applications considered in this European Standard includes (Figure 1):
¾   earth retaining structures, (vertical, battered or inclined walls, bridge abutments, bulk storage facilities), with a facing to retain fill placed between the reinforcing layers;
¾   reinforced steep slopes with a facing, either built-in or added or wrap-around, reinforced shallow slopes without a facing, but covered by some form of erosion protection without a facing, reinstatement of failed slopes;
¾   embankments with basal reinforcement and embankments with reinforcement against frost heave in the upper part.
Principles for the execution of other special geotechnical works using soil nails, bored piles, displacement piles, micro piles, sheet pile walls, diaphragm walls, grouting or jet grouting are established in other European Standards.
Reinforcement of road pavements is not covered by this Standard.

TC - Various modifications throughout text

his European Standard is applicable to the planning, execution, testing and monitoring of ground treatment by deep vibration achieved by depth vibrators and compaction probes.
The following types of treatment are covered by this European Standard:
   deep vibratory compaction to densify the existing ground;
   vibrated stone columns to form a stiffened composite ground structure by the insertion of granular material which itself shall be densified. Generally, stone columns have a diameter greater than 0,6 m and lower than 1,2 m.
The following treatment methods are covered by this European Standard:
   methods in which depth vibrators, containing oscillating weights which cause horizontal vibrations, are inserted into the ground;
   methods in which compaction probes are inserted into the ground using a vibrator which remains at the ground surface and which in most cases oscillates in a vertical mode.
Treatment methods are outlined in Annexes A and B.
The following treatment methods, among others, are not included in this European Standard:
   methods in which sand or stone columns are installed by means of impact or top vibratory driven casing;
   methods in which very stiff columns are formed either by the addition of cement to granular material or by the use of concrete or any other binder;
   dynamic compaction and other methods in which some form of treatment is applied to the ground surface;
   explosive compaction.

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.

.1 This European Standard establishes general principles for the execution of bored piles (see 3.2). NOTE 1 This standard covers piles or barrettes which are formed in the ground by excavation and are structural members used to transfer actions and/or limit deformations. NOTE 2 This standard covers piles with circular cross-section (see Figures 1 and A.1a)) and barrettes (see 3.3) with rectangular, T or L or any other similar cross-section (see Figure 2) concreted in a single operation. NOTE 3 In the standard the term pile is used for circular cross-section structure and the term barrette for other shapes. Both are bored piles. 1.2 This European Standard applies to bored piles (see Figure 3) with: - uniform cross-section (straight shaft); - telescopically changing shaft dimensions; - excavated base enlargements; or - excavated shaft enlargements. NOTE The shape of a pile base and of an enlargement depends on the tool used for the excavation. 1.3 This European Standard applies (see Note) to: - bored piles with a depth to width ratio  5; - piles (see Figures 1 and 3) with a shaft diameter 0,3 m  D  3,0 m; - barrettes (see Figure 2) with the least dimension Wi  0,4 m, a ratio LBiB / Wi between its largest and its least dimensions  6 and a cross-sectional area A  15 m²; - piles with circular precast elements used as structural member (see Figure 7) with a least dimension DP  0,3 m; - barrettes with rectangular precast elements used as structural member with a least dimension WP  0,3 m. NOTE The standard covers a large range of diameters. For small diameter bored piles less than 450 mm, the general specification can be adapted to cater for the lack of space (e.g. minimum bars number and spacing). 1.4 This European Standard applies to piles with the following rake (see Figure 4):

This European Standard deals with the execution of diaphragm walls and the practical aspects which must be taken into account in the production of the working drawings. Diaphragm walls can be permanent or temporary structures.

This standard specifies requirements, recommendations and information concerning the execution of permanent or tempory sheet pile wall structures in accordance with 2.4 of ENV 1991-1:1994 and the handling of equipment and materials. It does not give requirements and recommendations for the installation of specific parts of the structure such as ground anchorages and piles which are covered by other codes.

This standard is applicable to the execution, testing and monitoring of geotechnical grouting work. Specific aspects concerning design are provided since ENV 1997-4 has been abandoned. Grouting for geotechnical purposes (geotechnical grouting) is a process in which the remote placement of a pumpable material in the ground is indirectly controlled by adjusting its rheological characteristics and by the
manipulation of the placement parameters (pressure, volume and the flow rate). The following principles and methods of geotechnical grouting are covered by this standard : - displacement grouting (compaction grouting, hydraulic fracturing) ; - grouting without displacement of the host material (permeation, fissure grouting, bulk filling). Specialised grouting activities, generally associated with structural and/or emergency works, are not covered by this standard.

1.1 ST This Standard is applicable to the execution, testing and monitoring of jet-grouting works. Some considerations about design are also given. 1.2 ST The execution of jet-grouting works requires knowledge and experience in this type of contruction. NOTE 1: The jet-grouting process must be distinguished from the grouting processes covered by the standard EN 00288006.

1.1   This European Standard establishes general principles for the execution of bored piles (see 3.2).
NOTE 1   This standard covers piles or barrettes which are formed in the ground by excavation and are structural members used to transfer actions and/or limit deformations.
NOTE 2   This standard covers piles with circular cross-section (see Figures 1 and A.1a)) and barrettes (see 3.3) with rectangular, T or L or any other similar cross-section (see Figure 2) concreted in a single operation.
NOTE 3   In the standard the term pile is used for circular cross-section structure and the term barrette for other shapes. Both are bored piles.
1.2    This European Standard applies to bored piles (see Figure 3) with:
-   uniform cross-section (straight shaft);
-   telescopically changing shaft dimensions;
-   excavated base enlargements; or
-   excavated shaft enlargements.
NOTE    The shape of a pile base and of an enlargement depends on the tool used for the excavation.
1.3    This European Standard applies (see Note) to:
-   bored piles with a depth to width ratio  5;
-   piles (see Figures 1 and 3) with a shaft diameter 0,3 m  D  3,0 m;
-   barrettes (see Figure 2) with the least dimension Wi  0,4 m, a ratio LBiB / Wi between its largest and its least dimensions  6 and a cross-sectional area A  15 m²;
-   piles with circular precast elements used as structural member (see Figure 7) with a least dimension DP  0,3 m;
-   barrettes with rectangular precast elements used as structural member with a least dimension WP  0,3 m.
NOTE   The standard covers a large range of diameters. For small diameter bored piles less than 450 mm, the general specification can be adapted to cater for the lack of space (e.g. minimum bars number and spacing).
1.4    This European Standard applies to piles with the following rake (see Figure 4):
-   n  4 (  76°);
-   n  3 (  72°) for permanently cased piles.
(...)

This European Standard establishes general principles for the execution of diaphragm walls as either retaining walls or cut-off walls.
NOTE 1   This standard covers only structures constructed in a trench excavated with a support fluid or in dry conditions, where soil is removed and replaced by concrete or slurry and with wall thickness B ≥ 40 cm.
NOTE 2   Diaphragm walls can be permanent or temporary structures.
NOTE 3   The following types of structure are considered:
a)   retaining walls: usually constructed to support the sides of an excavation in the ground. They include:
1)   cast in situ concrete diaphragm walls;
2)   precast concrete diaphragm walls;
3)   reinforced slurry walls;
b)   cut-off walls: usually constructed to prevent migration of groundwater, clear or polluted, or of other contaminants present in the ground. They include:
1)   slurry walls (possibly with membranes or sheet piles);
2)   plastic concrete walls.
NOTE 4   Walls formed shallow vertical trenches (typically excavations with a ratio of depth over thickness D/B < 5 or D < 5 m) are not covered by this standard.

1.1   This Standard establishes general principles for the execution of micropiles.
They are for:
-   drilled micropiles a shaft diameter not greater than 300 mm;
-   driven micropiles a shaft diameter or a maximum shaft cross sectional extension not greater than 150 mm.
1.2   Micropiles are structural members to transfer actions to the ground and may contain bearing elements to transfer directly or indirectly loads and or to limit deformations. Their shaft and base resistance may be improved (mostly by grouting) and they may be constructed with (see Figure 1):
-   uniform cross section (straight shaft); or
-   telescopically changing shaft dimensions;
-   shaft enlargements; and/or
-   base enlargement.
1.3   Other than practical considerations, there are no limitations regarding, length, rake (definition of rake, see Figure 2), slenderness ratio or shaft and base enlargements.
1.4   The provisions of the Standard apply to (see Figure 3):
-   single micropiles;
-   micropile groups;
-   reticulated micropiles;
-   micropile walls.
1.5   The micropiles which are the subject of this Standard can be installed into the ground using drilling, driving or a combination of these methods.
1.6   The material of micropiles covered by this Standard can be:
-   steel or other reinforcement materials;
-   grout, mortar or concrete;
-   a combination of above.
1.7   Micropiles may be used for:
-   working under restricted access and/or headroom conditions;
-   foundations of new structures (particularly in very heterogeneous soil or rock formations);
-   reinforcing or strengthening of existing structures to increase the capacity to transfer load to depth with acceptable load settlement characteristics, e.g. underpinning works;
-   reducing settlements and/or displacements;
-   forming a retaining wall;
-   reinforcing of soil to form a bearing and/or retaining structure;
-   improving slope stability;
-   securing against uplift;
-   other applications where micropile techniques are appropriate.
1.8   Mixed-

1.1 This standard establishes general principles for the execution of displacement piles which are installes in the ground without excavation or removal of material from the ground except for limiting heave, vibration, removal of obstructions or to assist penetration. Piles are driven into the ground using impact, vibration, pressing, screwing or a combination of these methods. The material of displacement piles covered by this standard can be: -steel, -cast iron, -concrete, -timber, -grout, -combination of above.

TC - German version not alligned with E and F

This Standard is applicable to the installation, testing and monitoring of permanent and temporary ground anchors where the load capacity is tested. An anchor consists of an anchor head, a free anchor length and a fixed anchor length which is bonded to the ground by grout. The term "ground" is taken to encompass both soil and rock.

This European Standard deals with the execution of diaphragm walls and the practical aspects which must be taken into account in the production of the working drawings. Diaphragm walls can be permanent or temporary structures.

1.1 This standard establishes general principles for the construction of piles - which are formed in the ground by boring by excavation; and - which contain a structural member to transfer loads and/or limit deformations.1.2 The cross section of bored piles covered by this standard can be of - circular shape (see figure 1), - barrette shape if the section is concreted ina single operation. 1.3 A barrette may be square, rectangular, T- or L-shaped inplan or have any other similar configuration (see figure 2).