Diaphragm walls are reinforced concrete walls constructed underground using a slurry technique. The slurry balances inward hydraulic forces and prevents water from entering the trench during construction. Diaphragm walls can be between 300mm to 1500mm thick and up to 50m deep. They are commonly used in congested areas and for constructing deep basements due to their ability to be installed close to existing structures.

1. Diaphragm Wall
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2. Diaphragm Wall
 Diaphragm wall is generally reinforced concrete wall
constructed in the ground using under slurry technique.
 The slurry forms a thick deposit on the wall of the
trench which balances the inward hydraulic forces &
prevents water flow into the trench.
 Thickness of the wall can be between 300mm to
1500mm.
 Depth of the wall can go up to 50m.

3. Diaphragm Wall Application
 Commonly used in congested areas.
 Can be installed in close proximity to
existing structure.
 Practically suited for deep basements.

4. General Procedure of Construction
1. The excavation is carried out using a heavy self guided
mechanical grab suspended from a large crawler crane.
2. The diaphragm walls were excavated and constructed in
discrete panels of between 2.8m and 7.0m lengths.
3. As the excavation proceeds, support fluid was added into the
excavation to maintain the stability of the surrounding ground
and to prevent a collapse. This fluid is called “Bentonite” or
“slurry”, which is a poser made of a special type of soluble clay
and is mixed at the mixing plant with potable water.
4. When the excavation is completed, the reinforcement cage
will be lowered and the concrete procedure will begin.

5. Product A Product B

7. Types of Diaphragm Walls
 Structural Diaphragm walls: they are used as
retaining walls for the perimeter walls of deep
basements and underground parking facilities and
subways.
 Load bearing walls: they are used in place of drilled
piers in foundation of tall buildings, bridge and
piers.
 Cutoff walls: in hydraulic structures diaphragm
walls are used as impermeable cutoffs to prevent
seepage below earth dams and weirs.

8. Cut & cover Tunnel

9. Cut off Wall

10. Under ground water tanks

11. Advantages of Diaphragm Wall
 Suitable for unstable soil profiles below
water table.
 Limited construction time.
 Where deeper than normal cantilever
support may needed.
 Designable to carry vertical loads.
 Construction time of basement can be
lower.
 Minimize the settlement of adjacent
building.

12. Cont.
 Provides strong & water tight walls.
 No vibration during installation.
 Noise level limits to engine noise only.
 Can be used for seepage control in dams.

13. Disadvantages
 Not economical for small & shallow basements.
 Require special equipment.

14. Questions & Clarifications?

15. Thank You