Troxler nuclear density testing on a slope
Troxler nuclear density testing on a slope
(OP)
What are the specifications to conducting density testing on a slope? Is it required to cut out a "notch" so that the gauge is level in reference to the horizon line? Or can you directly test on a slope as long as the surface is flat?





RE: Troxler nuclear density testing on a slope
RE: Troxler nuclear density testing on a slope
This depends on the fill. I have done extensive landfill work, where the fill for the clay line is place on the slope in 6 inch lifts, not level as indicated here (so many short lift interfaces would be bad, and very hard to construct).
So, just get it flat, unless they should be placing it level. Then, it is just the pain in the but of walking and testing on the slope that will be a pain.
RE: Troxler nuclear density testing on a slope
How steep was the slope for the clay line that was filled?
RE: Troxler nuclear density testing on a slope
However, I too have performed clay-lined landfill construction where the testing was performed on slope. Our drive cylinders always came back from the lab within 2% of the gauge readings, indicating a valid test by our specs.
Any idea why ASTM requires horizontal?
RE: Troxler nuclear density testing on a slope
With some of the synthetic caps, the slope has decreased to 4:1 to allow for veneer stability at the liner/cover soil interface.
As you can calculate, the horizontal thickness of a 2' liner on a 3:1 is around 6.5'. To use normal equipment, this would need to be double to do a horizontal lift, and then be cut off (or left). This gets to be impractical, cost prohibitive, and a waste of clay resouces, and in my experience (many, many landfills from many design firms), it is never done.
RE: Troxler nuclear density testing on a slope
RE: Troxler nuclear density testing on a slope
The problem there is not testing on a slope, but compacting on a slope. What I've run into is contractors that want to place their fill at an angle. If the contractor is placing against a slope, they should start at the bottom using horizontal lifts and place up, not place sideways laterally from the slope surface. Soil compacts better when there's a hard suface to compact against(down), not an angled surface that the lift can slide on. I've only been on one job where the contractor tried to build this way, and it made a big difference as far as densities were concerned.
RE: Troxler nuclear density testing on a slope
I’m not sure if you know just how inefficient it can be, until you see it done. The compactor looses some compactive effort due to the slope, but I can’t count the number of times I have seen a D6 push an 815 compactor up a slope, blade to blade. This takes a lot of extra time. I have even seen pictures of compators being pulled up and down on cables. Then there is the need to water the material. Definitely interesting on a slope. Sure it can be processed in the pit, but with a tight moisture spec, inevitably there is the need to do it in-place.