Standards Development

Scope

1.1 This document establishes general principles for the execution of diaphragm walls and barrettes 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 Walls which deviate from the following clauses in this section can be considered as diaphragm walls provided the execution principles correspond to this document (see Clause 8).

NOTE 3 The term diaphragm wall is used throughout this document and, where applicable, includes barrettes.

1.2 This document applies to diaphragm walls which may have various cross-sectional shapes, uniform over depth (straight shaft), see Figure 1 and Figure 2.

1.3 This document applies to diaphragm walls with

— a wall thickness B ≥ 0,4 m,

— a depth to width ratio D/B ≥ 5, with D ≥ 5 m.

1.4 This document applies to permanent or temporary works for:

— retaining walls

— cut-off walls

— foundations (barrettes), usually formed by single panels or a combination of panels.

1.5 This document applies to diaphragm walls where excavation methods are either continuous or discontinuous using support fluids for stabilizing the excavation walls where required.

1.6 This document applies only to execution methods that allow the designed cross-sections to be produced.

1.7 This document applies to diaphragm walls constructed of:

— 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 gap between the element or tube and the ground is filled by concrete or self-hardening slurry.

NOTE Concrete can be substituted by grout, where applicable.

Key

1 Wall thickness (B) 7 Guide-wall 2 Horizontal length of reinforcement cage 8 Cut off level 3 Cage width 9 Vertical length of reinforcement cage 4 Length of panel 10 Reinforcement cage 5 Working platform level 11 Depth of excavation (D) 6 concreting level 12 Concave portion of curved joints

Figure 1 — Typical geometry of a panel

Key

L Barrette length B Barrette thickness A Cross-sectional area of the shaft

Figure 2 — Barrette