Retaining walls can be both concrete sheet walls, or wood sections inserted between the 'I' beam piles. And in some cases, I have seen both concrete sheet walls and wood retaining walls used in the same excavation - if I recall correctly, I think the King Blue site may have used both types of retaining wall. HOWEVER - the manner in which the I beams were placed was the same - the holes were excavated using a SHORING machine, the I beams were inserted in the hole by the crane cable attachment at the top of the shoring machine, and then as the excavation proceeded, the wood timber sections were inserted. The 'I' beam piles are either supported in place by tie-backs, or in the cases were an adjoining property owner would not accept a tieback agreement and reasonable fee, the pile would be supported by steel beams within the excavation.
The operational consequences, disruptions, risks and associated potential damage costs from pile driver vibrations are such that, in the 38 years we have lived in Toronto (since moving here from Montreal in 1979), I have yet to see an actual pile driving based retaining wall being created in downtown Toronto.