Soil Washout Fill Options 1

[gmmolina]

I am looking for alternatives to filling an area where soil has washed out from under a pre-cast stadium seating stand. Approx. 2 cy of soil has washed out around each of the concrete columns (which are supported on piers). In total about 30 cy of voids will have to be filled.

Other than using soil and compacting it, what are some other options I may look at? I have researched and found some articles on CLSM (controlled low strength material). Any recommendations?

Many thanks in advance.

 

[Ron]

CLSM would be a good point to start. If too expensive in its typical form, have the supplier reduce the cement amount, though it won't reduce the cost a whole lot.

You can also use cellular concrete (Elastizel).

 

[ccor]

Why is the soil washing out? Has it been addressed? May want to look at the root cause before addressing the symptoms.

 

[oldestguy]

What caused the wash out? Can there be future washings in the same areas? If so, any cememted material fill is likely to hang there where it was placed and the future wash action will go on beneath it. Then you have an even worse situation.

Use the general principles for shore protction to prevent erosion by wave action. There you allow some permeablity of the "protection", but you have sufficient filtering action that no erosion of original soil takes place, as well as suffieiently large rock to stop mass erosion of this fill. Size the large size to resist your strongest flow velocity.

Not knowing your exact set up, considering future water flow again, I'd opt for a graded granular fill, say from 8 inch rock down to the fines. This might be called Run of Crusher rock.

To provide support (sounds like you don't need it), this can be compacted to some extent, as with a back-hoe mounted vibrating plate compactor, with some reach into confined areas, shoving laterally.

This material will generally prevent undermining under it because it is not rigid.

 

[gmmolina]

Thank you for all of the responses. We have resolved the source of the erosion, but were just looking for alternatives for the fill.

Thanks again.

 

[reddog99o]

Try a lean concrete mix with very fine aggregate, 3/8" minus and superplasticizer to make it flow. Alternatively, use sand/cement with enough water to make it flow.
Remember, your looking for the equivalent of compacted material, not compressive strength in whatever mix you use. Another thought would be to replace some of the cement with a bit of bentonite to "slick" it up.


R.A. Hassett, P.E.
rah1616@hotmail.com