building on a land filled rice paddy. time frame for land settling

[jackrossi]

I am planning the construction along a national road (PP to Siem R) of a building (20x20m 2 floors brick/concrete commercial structure) however the land is currently half dry-half wet rice field and it will require 1m to 1.5m of land fill. Locals which own houses along the same stretch of land believe that i could build immediately, the local engineers prefer to wait one rainy season after landfill, than proceed to compact the land again with a bulldozer, in the west we would probably wait even longer. Its not an issue of safety as the building is just 2 floors but a minor settling of the land could cause cosmetic cracks which i would prefer to avoid.
What's is your suggestion regarding the time frame before beginning construction?

[loy division]

I am planning the construction along a national road (PP to Siem R) of a building (20x20m 2 floors brick/concrete commercial structure) however the land is currently half dry-half wet rice field and it will require 1m to 1.5m of land fill. Locals which own houses along the same stretch of land believe that i could build immediately, the local engineers prefer to wait one rainy season after landfill, than proceed to compact the land again with a bulldozer, in the west we would probably wait even longer. Its not an issue of safety as the building is just 2 floors but a minor settling of the land could cause cosmetic cracks which i would prefer to avoid.
What's is your suggestion regarding the time frame before beginning construction?

Trust the engineers. Better yet, consult a Western engineer. I'm of the opinion that compacting the land twice is logically the safer choice, especially if the wet season prompts movement.

Edit: I'm assuming you're doing something like this:

[alifeapart]

Best solution is apply compaction at the time of land filling, layer by layer, with a vibrating plate or heavy roller.

If time is on your side wait for rains also, but not essential if well compacted as aforementioned.

[jackrossi]

Best solution is apply compaction at the time of land filling, layer by layer, with a vibrating plate or heavy roller.

If time is on your side wait for rains also, but not essential if well compacted as aforementioned.

how many layers in a meter would you suggest to make?

[ricecakes]

Unless it's properly compacted you can expect the land to be settling for a few years.

[Kampot Homesteader]

it depends on the type of fill, but the heavy clay mix i have used in the past settles almost 50cm over one rainy season. i will typically add 1 cubic meter of fill in old paddy land to get a good land height and then build the house an additional 2-3 steps up from that.

[Duncan]

I am planning the construction along a national road (PP to Siem R) of a building (20x20m 2 floors brick/concrete commercial structure) however the land is currently half dry-half wet rice field and it will require 1m to 1.5m of land fill. Locals which own houses along the same stretch of land believe that i could build immediately, the local engineers prefer to wait one rainy season after landfill,

than proceed to compact the land again with a bulldozer,

in the west we would probably wait even longer. Its not an issue of safety as the building is just 2 floors but a minor settling of the land could cause cosmetic cracks which i would prefer to avoid.
What's is your suggestion regarding the time frame before beginning construction?

A bulldozer cannot compact the dirt. The reason a bulldozer has wide tracks is so it has less pressure on the ground than say a wheel type vehicle. I have driven bulldozers across soft swampland whereas a tractor will just bogg down.

Which is why I should have been using a bully here.

[YaTingPom]

See. Now I want to buy a farm so I can scoot around on an red International tractor! (Or a green John Deere)

[alifeapart]

Best solution is apply compaction at the time of land filling, layer by layer, with a vibrating plate or heavy roller.

If time is on your side wait for rains also, but not essential if well compacted as aforementioned.

how many layers in a meter would you suggest to make?

Depends on the backfill. Average will compact at a ratio of 1.3cbm to 1.0cbm. At average, if it was me, I would be doing compaction at 200mm layers and wetting down also if it was the dry season. If the backfill was loose or sandy, perhaps thinner layers.

A vibrating plate will have the best effect, with an experienced user. Rolling only does not seem to really compact as efficiently.

[Kachang]

Assuming the land you want to build on is solid enough, why don't you put the concrete poles on the land now, and fill it up later and corntinue to build on your solid poles? Will cost you a few extra meters of concrete, and some stones, but at least the foundation will be solid. Besides, if you build on the 'new land' you have to dig deeper than the new soil anyway to get a solid foundation. I once heard 2.80 meter is needed at least to prevent termites from digging under you poles.

[jackrossi]

Assuming the land you want to build on is solid enough, why don't you put the concrete poles on the land now, and fill it up later and corntinue to build on your solid poles? Will cost you a few extra meters of concrete, and some stones, but at least the foundation will be solid. Besides, if you build on the 'new land' you have to dig deeper than the new soil anyway to get a solid foundation. I once heard 2.80 meter is needed at least to prevent termites from digging under you poles.

yes forgot to mention that most of the foundation will be laid before filling, still we will be adding a small layer in some areas (and later dig the trenches for the foundations) in order to work on properly dry land rather than building foundations on wet soil. If you dig now at the back of the lot any hole or trench for footings would get filled and the concrete absorb too much water making it weaker.

the plot is 30m front 50m-59m sides and 22+m at the back in the shape of a rectangle trapezoid.

[starkmonster]

Just drive piles and be done with it. If you're just doing pads not driving piles then you need to do soil testing (ili provide a quality service for this) prior to construction.

Sandy ex-paddy land will more than likely fail, even after a year or two, so better just save himself the time and go straight for piles.

We built our three level house on pads, but had a professional site survey and soil tests before that call was made.

[jackrossi]

Just drive piles and be done with it. If you're just doing pads not driving piles then you need to do soil testing (ili provide a quality service for this) prior to construction.

Sandy ex-paddy land will more than likely fail, even after a year or two, so better just save himself the time and go straight for piles.

We built our three level house on pads, but had a professional site survey and soil tests before that call was made.

yes piles is the way to go, when you say on pads, you mean directly on a slab or slab + a square footing?

[starkmonster]

Square footings. If you are driving piles you don't need to worry about the ground settling as the footings will be resting on the piles, the ground floor beams on the footings and the ground floor pad on the beams. It's a more expensive route, because of the cost of the piles and the ground floor pad, but it will give you peace of mind and no need to wait.

If it's a large floor space and a ground floor pad will be costly, but as it's a commercial property that I guess won't have any expensive flooring, you could even skip the ground floor pad and keep some money back to repair if it sinks anywhere, just make sure that any underground piping is suspended from the beams rather than resting on the fill, as your pipes will split. Billy Bodgejob 101.