Swelling clays in the landfill liners and covers
Swelling clays in the landfill liners and covers
(OP)
I am wondering whether using swelling clays in the construction of landfill liners and covers is an issue or not. Any reference will be appreciated.





RE: Swelling clays in the landfill liners and covers
I'd avoid it.
Regards,
DRG
RE: Swelling clays in the landfill liners and covers
Here's where the body is buried: To properly place clay liners, you MUST place them wet of optimum. There is greater than a 2 fold decrease in hydraulic conductivity between the same clay compacted below the optimum moisture content and above the optimum moisture content. For the case that you place the clay in the 90 percent saturation range and then let it lie - it'll crack (a bad thing). Therefore, you MUST immediately cover a clay liner after placed and compacted to spec.
f-d
¡papá gordo ain’t no madre flaca!
RE: Swelling clays in the landfill liners and covers
RE: Swelling clays in the landfill liners and covers
RE: Swelling clays in the landfill liners and covers
RE: Swelling clays in the landfill liners and covers
I had the unique opportunity some years ago to visit some covered landfills that had been built to state specifications for cover.
The state enforcement guys were bragging up the imperviousness of this form of cover. They wanted to show me one of the better landfills. I had along a folding ruler. These "experts" from the state agency were mortified when I showed them the deep, wide, cracks in this cover material, running from surface into the trash below.
After that I had no difficulty convincing them that their spec was not the best and that lower plasticity material was a better choice.
RE: Swelling clays in the landfill liners and covers
On the matter of tension cracks, I've also seen some doosies - as oldesguy says, feet deep.
f-d
¡papá gordo ain’t no madre flaca!
RE: Swelling clays in the landfill liners and covers
RE: Swelling clays in the landfill liners and covers
Here in my neck of the woods (upstate New York) I've been working with two landfills that were capped with soil covers over a decade ago (18" 1E-7 cm/s glacial till + 24" barrier protection layer + 6" topsoil). Hauling records indicate that leachate flows have been increasing significantly at both of these sites over the years. I think most of the landfills in this area nowadays are capped using geomembranes.
Sorry, I have no experience with GCLs as covers.
Mark