CEN/TC 288/WG 15 - Bored piles - Diaphragm walls

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.
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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.