kechha2060
Civil/Environmental
Does anyone have any experience on designing/constructing roadway on top of landfill area. We are considering an asphalt pavement (8" thick 'no basis') knowing issue of maintenance.
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roadway over Landfill
- Thread starter kechha2060
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Is it for public traffic?
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -
MiketheEngineer
Structural
My guess is a lot of pot holes and uneven surfaces....
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kechha2060
Civil/Environmental
Yes, roadway is for public predominately passenger car but truck loads are also anticipated. Design std calls for 20k vpd with 10% truck traffic. c
I would make sure your client realizes this roadway will require major maintenance on a frequent interval, regardless of how thick you make the structural section. Don't expect a 20-year design life. Expect significant and highly variable settlement. Also, collection and mitigation of LFG is a risk factor and additional cost you will need to address in your design and construction. another question - how long ago did they close the landfill, what was the closure system and what kind of landfill is it?
the problem with a bridge is the piles would penetrate the landfill, leachate and (likely) into the water table. I'd consider a soil raft (i.e., granular fill and geogrid) and anticipate a maintenance program.
I'm pretty sure my DOT wouldn't accept this road into our system though. . .
f-d
¡papá gordo ain’t no madre flaca!
I'm pretty sure my DOT wouldn't accept this road into our system though. . .
f-d
¡papá gordo ain’t no madre flaca!
Dozerman56
Civil/Environmental
I don't know about over trash but I've seen a layer of geogrid and a foot or two of crusher run heal some really miserable earth.
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kechha2060
Civil/Environmental
Landfill is solid waste and construction waste site. 3' clay cap, closed in 80's per records
civilman72
Civil/Environmental
If you have some time, you may consider an overburden load to promote settling, prior to actual road construction.
You can also consider starting with a gravel driving surface for a few years and then adding asphalt when settlement and maintenance have (hopefully) started to decrease.
But I agree with the previous posts, your maintenance costs for this type of road will be relatively significant.
You can also consider starting with a gravel driving surface for a few years and then adding asphalt when settlement and maintenance have (hopefully) started to decrease.
But I agree with the previous posts, your maintenance costs for this type of road will be relatively significant.
If it was closed in the 80s, do you have some old surveys and new surveys you can compare, to see how active the settlement has been over time? I seem to recall anerobic bacteriological processes take some 30+ years to finish up in landfills, but that's from memory and it could be longer.
If you want a highly creative solution, retrofit the landfill for aerobic bacteriological processes - basically pump air through it and also recirculate lechant to keep the temperature low enough to prevent it from catching on fire. That should kickstart whatever remaining activity it's got left, and the whole thing could be inert in a few months. Then build over the inert landfill.
I was at Arcadis in the late 1990s when they did a pilot project that involved aerobic landfilling. I don't know if it ever caught on, but they were able to take a regular household trash landfill and turn the whole thing to dirt in a few months instead of what would normally have taken years.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -
If you want a highly creative solution, retrofit the landfill for aerobic bacteriological processes - basically pump air through it and also recirculate lechant to keep the temperature low enough to prevent it from catching on fire. That should kickstart whatever remaining activity it's got left, and the whole thing could be inert in a few months. Then build over the inert landfill.
I was at Arcadis in the late 1990s when they did a pilot project that involved aerobic landfilling. I don't know if it ever caught on, but they were able to take a regular household trash landfill and turn the whole thing to dirt in a few months instead of what would normally have taken years.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -
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kechha2060
Civil/Environmental
thanx for your suggestion and insight. How expensive is aerobic process cost? bridge and surcharge are cost and schedule prohibitive
o.k. I just can't find the citation, so I'm going from memory. . .
Anders Bjarngard published his thesis and it had to do with the settlement of municipal waste landfills. Just like soil, there is initial "modulus-based" settlement (after all the trash does have some modulus value and there will be some immediate compression). There is also settlement as related to change in void ratio in the absence of change in effective stress - i.e., secondary compression. You see usually we are not dealing with consolidation as the landfill materials are usually not saturated and if so the permeability of the trash is pretty high.
Anders Bjarngard looked at historical data from landfills all over the place and determined that secondary compression (C-alpha) is similar to that for soil - problem is that the value of C-alpha INCREASES over time to some value, "C-alpha-max." He provides graphed data and values for C-alpha and C-alpha-max. I used to (likely still do) have a copy of his thesis. If you google Anders Bjarngard you will find ASCE publications that you can purchase and I think these publications must cite his original work. They have interesting titles and may be great publications, but I'm not spending the money to further engage in this discussion. I am interested in what you find.
I'm not taking anything away from what's already been posted. The variation in C-alpha is related to decomposition rate and all those anaerobic processes. I'm not sure that unleashing aerobic processes in a landfill is the right or wrong thing to do. If the debris has been in place for 30 years and you consider the extent of compression that's likely occurred, the forecasted settlement (compression) using secondary compression values may be manageable in conjunction with a soil raft.
Face it, you are not doing "generally accepted" engineering practice and your client should recognize this risk before you sell yourself as some engineering expert.
f-d
¡papá gordo ain’t no madre flaca!
Anders Bjarngard published his thesis and it had to do with the settlement of municipal waste landfills. Just like soil, there is initial "modulus-based" settlement (after all the trash does have some modulus value and there will be some immediate compression). There is also settlement as related to change in void ratio in the absence of change in effective stress - i.e., secondary compression. You see usually we are not dealing with consolidation as the landfill materials are usually not saturated and if so the permeability of the trash is pretty high.
Anders Bjarngard looked at historical data from landfills all over the place and determined that secondary compression (C-alpha) is similar to that for soil - problem is that the value of C-alpha INCREASES over time to some value, "C-alpha-max." He provides graphed data and values for C-alpha and C-alpha-max. I used to (likely still do) have a copy of his thesis. If you google Anders Bjarngard you will find ASCE publications that you can purchase and I think these publications must cite his original work. They have interesting titles and may be great publications, but I'm not spending the money to further engage in this discussion. I am interested in what you find.
I'm not taking anything away from what's already been posted. The variation in C-alpha is related to decomposition rate and all those anaerobic processes. I'm not sure that unleashing aerobic processes in a landfill is the right or wrong thing to do. If the debris has been in place for 30 years and you consider the extent of compression that's likely occurred, the forecasted settlement (compression) using secondary compression values may be manageable in conjunction with a soil raft.
Face it, you are not doing "generally accepted" engineering practice and your client should recognize this risk before you sell yourself as some engineering expert.
f-d
¡papá gordo ain’t no madre flaca!
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