[scott C]

My current tiered retaining wall project is becoming a nightmare. I have encountered springs behind each wall and clay so heavy and slick my tracked excavator has a hard time moving around.

As far as constructing the walls I have been putting 4- 5 incheds of a crushed number 2 stone down compacted every 2 inches to help with drainage and compaction of the clay. Then a geotextile, crusher run, pipe at the base course and of course clear stone behind the wall.

I am concerned that I am allowing the spring water to run under my walls in the # 2 stone rather than behind my wall. Hindsight tells me I should have dug a trench 2-3 feet behind my wall and deeper than my base to allow the water to flow into .

Any thoughts

[Matt Kulp]

If it were me, I would contact an engineer. With the amount of water you will have pushing against the wall, you will need a special drain at the bottom (Chimney drain, Blanket drain). JMO

[Stonehenge]

I have to agree with Matt - this may be one of those times where you tell the client you've got to stop the bus and figure out where it's going next.

I've never encountered live spring under/behind any of our walls, but I can't imagine a project maintaining it's integrity long-term with that situation, without some serious consideration paid to the water issue.

[Paul]

If your into a hillside the problem might be water sheeting between layers of different soils. A trench farther back dug below your excavation, filled with pipe and gravel daylighted to a drain might clear up the problem. One thing is I don't know if all the rain you've been getting is leading to the problem this year or not.

[Fine Edge]

We had a similiar problem with springs a few years back. Augered about 25 12" holes in this guys yard thinking we could find the source. Turns out that the spring was just travelling through all different layers as Paul said and was also finding it's way through every decaying tree root ( many were cut down previously).
We tried a few deep trenches filled with pipe, gravel, etc. that lead to a creek and tried to catch what we could.
I could see it getting expensive to try and catch all water in certain difficult situations.