install sump between piers

[Datezam]

We wanted to install sump with less than 4' clearance from the piers. Would it be ok to excavate with a trench box? The other option might be to fabricate precast sump (with no integral bottom) lowered to design elevation by means of hydro/vacuum/fluid jet excavation. Sump bottom to be doweled-in cast in place with key way and/or approved water stop provisions.
Please advice which way to go.
Thank you

 

[oldestguy]

In order to help, it would be good it you can say what sort of a job this is, the general soil types, and maybe even post a sketch of the situation. Right now we can't give much help until more is known.