Drainage Ditch Sidewall Failure 1

[JMel]

Have poured approx 1200' paved ditch. All concrete/steel passed spec inspection. Large Paved area adjacent to 200'.
2 drain outlets from paved area about 30' from top of wall. Wall failed in this area (large longitudional crack @ approx. 3' up.) Wall 9' high on 1:1 (45 degree)slope. Fill material red clay. Compaction spec acheived. Significant rain event preceeded break. Remainder of wall no problem. Hydrologist suggests that either rain retained in equipment (Euclid trucks) ruts or equipment loads passing behind wall during construction are cause. Some agree, I doubt. Any ideas, suggestions,etc?

 

[cvg]

how about leaking joint in the drain pipe, saturating the subgrade behind the wall?

 

[oldestguy]

More info please.

Was this wall designed for saturated clay, expansive clay?? Exactly what backfill condition assumed?

Is that 1:1 slope included in the wall design pressure

Any backfill drainage features included?

Does the design assume that upper paved area will be a waterproof roof?

Also what kind of country: arid, temperate, cold??

 

[dirtsqueezer]

I like oldestguy's entry. I've passed compaction on clay here in Washington State, 90% min, that came up 85% or less after a winter season. It is also telling that failure came near a drainpipe, ie. where all the water is flowing. It might be worth the money to get a local geologist consult, as this may not be the first instance you see. Of course, the fix might possibly just be replacement of this red clay, but at least you'd have it all on paper.

Good luck!