Connection between an existing and new subways

[HighPanda]

I have a problem about extension of an existing subway.

I did diaphragm wall before and I understand it is not difficult to make a NEW diaphragm wall watertight by placing waterstops before concreting.

However, I have no clue of how to make waterstop fitting into the slabs and walls of the existing subway.....

 

[JAE]

Try looking at hydrophilic waterstops:

Hydrotite by Greenstreak

Synko-flex by Henry

 

[hokie66]

I wouldn't be too sure about your statement that "it is not difficult to make a NEW diaphragm wall watertight". Water resistant, yes, but almost all diaphragm walls have infiltration issues if they extend below the water table.