Diaphragm wall permeability spec

[Zambo]

Can anyone recommend to me an international standard or code of practice for diaphragm wall construction. The specific point I'm interested in is a permeability specification for the completed wall including the vertical panel joints.

Thank you for your advice.

 

[BigHarvey]

There is a european norm for diaphragm walls : EN 1538 . It doen't say anything about permeability. In the french DTU 14.1 ( NF P 11-221 ) you have something about the performance of a diaphragm wall :
daily average over a year for the complete enveloppe 0.5 l/m2/day
daily average over a week for the complete enveloppe: 1 l/m2/day
No area of 10 m2 with more than 2 l/m2/day over a week.

 

[Zambo]

BigHarvey,

thanks for your helpful reply. I am currently referring to EN 1538 but as you state permeability is not quantified. The French standard you refer to is useful in that it gives a performance standard, do you know where I can get an english version?

What I would really like (and what I think is really not available) is a leakage rate for the face of the wall and panel joints only (i.e I expect the "complete envelope" allows for some leakage at the connection between the base slab and the wall, which is not the responsibility of the diaphragm wall contractor, and possibly some seepage at the base slab itself)

On top of that it would be good to have a specification for damp patches, a size (or percentage) and a dampness reading for the concrete, say 85% RH.

So BigHarvey - any ideas!

 

[BigHarvey]

Zambo

The norm to which I refer doesn't exist in an english version ... because it's intended for the french market. It's a general waterproofing norm which includes some values for diaphragm walls. They do not separate joints and walls : values are for the complete enveloppe and the "patch" surface is 10 m2 !.
You might try to concentrate on the following points :
1)cement content of concrete set to a minimum value of 400 kg/m3. Ad an "hydrofuge" or silica fume to the formula
2)be very strict on bentonitic mud quality ( the quality of the mud makes the quality of the joints and of the wall)
3)impose a single 150 mm waterstop joint between panels
If things go wrong, joints between panels can and should be treated (unless you deal with potable water inside the box )by grouting as soon as there is a noticeable leak. For humidity patches, unfortunately there is no solution to my knowledge but it should not happen in normal working conditions ( putting silica fume in the concrete formula in advance would help )