Circular earth retention wall design methods

[Saralex]

Contractor is responsible for design of temporary ERS for a launching and receiving shaft for a sewer tunnel. Inside diameter 35 feet and excavation depth 42 feet. Contractor proposing a secant pile wall with 2 foot diameter auger cast piles, every other pile steel reinforced. His design analysis is based on a lateral load pile program, and further supplemented with a structural software program modeling the ERS shaft as a concrete tank below ground. Has anyone ever heard or seen an attempt to model/analyze a circular ERS shaft in this manner?

 

[cntw1953]

No direct experience on this. Just a little thought.

1. The pile is critical at driving/construction stage only.
2. Upon completion, the pile wall subjects to axial compression mainly, if properly aligned.

Looks like his method is ok (to me).

 

[cntw1953]

Whalers and bracing are critical in maintianing the piles as an integral unit.