backfill (behind concrete structure)

[Good_Guy]

I would like to know if the material to be used as backfill behind concrete structure is OK

Specification requirement

Specification for backfill material


a) Native Backfill - Excavated materials such as clay and muck are not suitable as backfill material. Others that are free from grass, roots, brush, vegetation and boulders may be used. Rock pieces having maximum dimension greater than
75 mm shall not be used as native backfill.

(b) Imported Backfill - Any earth material except clay, muck and boulders`
satisfying the specification for native backfill and is capable of being compacted in the manner specified in the drawings.


(c) Soil materials that have a plastic index higher than 30 are not permitted. For granular fill materials the following grading shall be met


Grading for Granular Fill Materials


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Proposed material property : The geotech engineer says that a gradation report is not required as only the PI<30 is enough

The material to be imported is a CLAY/Silty CLAY, fine to medium gravel, yellow/brown in colour and PI<30


IS THE MATERIAL OK to be used as backfill behind concrete structures?

 

[LittleInch]

I think you're in the wrong forum?? This one is for pipelines and piping, not structural design.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Good_Guy]

Thank you