prEN 1536

1.1 This document establishes general principles for the execution of bored piles as per the execution specifications.
NOTE 1 It is expected that the execution specifications define the execution standard to be applied based on EN 1997 where relevant.
NOTE 2 Piles which deviate from the following clauses in this section can be considered as bored piles provided the execution principles correspond to this document (see Clause 8).
1.2 This document applies to bored piles (see Figure 1) with:
— uniform cross-section (straight shaft);
— telescopically changing shaft dimensions;
— excavated base enlargements; or
— excavated shaft enlargements.
1.3 This document generally applies to bored piles with:
— a shaft diameter 0,3 m ≤ D ≤ 3,0 m;
— a depth to width ratio ≥ 5, with a depth ≥ 5 m;
NOTE
This document can apply to bored piles with a shaft diameter of less than 0,3 m or more than 3,0 m where the general principles allow the execution in accordance with this document.
1.4 This document applies to permanent or temporary works for:
— piled foundations,
— retaining walls.
NOTE
This document can apply to rigid inclusions for ground improvement, and to cut-off walls.
1.5 This document applies to piles with the following rake (see Figure 2):
— n ≥ 4 (Θ ≤ 14°);
— n ≥ 3 (Θ ≤ 18°) for permanently cased piles
— n ≥ 10 (Θ ≤ 6°) for piles where the reinforcement cage is installed after concrete placement.
1.6 This document applies to bored piles with the following dimensions of the shaft or base enlargements (see Figure 1):
a) base enlargements:
1) in non-cohesive ground: DB/D ≤ 2;
2) in cohesive ground: DB/D ≤ 3;
b) shaft enlargements in any ground: DE/D ≤ 2;
c) slope of the enlargement in non-cohesive ground m ≥ 3;
1) in non-cohesive ground: m ≥ 3;
2) in cohesive ground: m ≥ 1.5.
1.7 This document applies to:
— single bored piles;
— bored pile groups (see Figure 3);
— walls formed by piles (see Figure 4).
1.8 This document applies to bored piles where excavation methods are either continuous or discontinuous using support methods for stabilizing the excavation walls where required.
NOTE
Where a continuous flight auger is used for excavation with partial displacement of soil, the pile is considered a partial-replacement pile and its execution is covered by this document.
1.9 This document applies only to execution methods that allow the designed cross-sections to be produced.
1.10 This document applies to bored piles (see Figure 5) constructed with:
— self-hardening slurries;
— unreinforced (plain) concrete incl. plastic concrete;
— reinforced concrete;
— concrete reinforced by structural elements (reinforcing elements);
— precast concrete (including prestressed concrete) elements or steel tubes where the annular gap between the element or tube and the ground is filled by concrete.
NOTE
Concrete can be substituted by grout, where applicable.