3.5' Allan Block wall the bottom of a POND

[EITZM]

A contractor is questioning the possibility of installing a 3.5' Allan block wall at the bottom of a dry pond with an extra 3 foot of storage at 3:1 slope backfill without a professional engineer's design. The plans call for a design's professional design for walls over 4'. Should the contractor submit a PE design or would the typical detail suffice for this application. Feedback would be greatly appreciated. Thanks

 

[EireChch]

Where i have practiced, retaining walls with level backslope or downslope under 1-1.5m height generally dont require specific design and can use generic allan block designs.

A 3.5ft wall with a 1:3 backslope may not require engineering design but maybe a statement from a geotech saying it should be ok or not.

I think Allan Block have design tables/sheets that consider non-level backslope and downslope.