Hill site to be re-shaped….method/cost?

[cheeryble]

Hi

We have come to the conclusion the shape of my wife's new hillock is far from optimal.

It has a flat area on top plenty enough for a house but 40% of the top is much lower and more or less wasted.

The other 50% of the land is too sloped for comfort.

The last thing is a lowest level under the slope itself needs smoothing out flat for the uncle to move his house to.

We are therefore considering cutting down the top by 2m or so, and dragging the dirt to fill the wasted low top area to about the same level.

As for the strongly sloping area, why not cut in a couple of big terraces?

There are rocks protruding in some places.

These are nice looking and may be a blessing and a curse.

The blessing is maybe the rocks could be "naturally" arranged to support the terraces about 2-3m high each.

The curse I have no experience of……will the rocks obstruct a sizeable macro? Or will they pull straight out?

I say macro instead of bulldozer as there is a 50 foot cliff (previously mentioned on this forum) on one side of the land which stands about 80° to the horizontal….ie dangerous to heavy machinery near the edge, it would be best standing back and extending it's claw.

So I envisage a large macro cutting into the dirt about 4 or 5 feet from the edge and leaving a sort of hard red earth wall instead of building one which is needed for safety. A bit like a red dirt castle in Mali, even things could be planted in it!

So bro-in-law has approached a man to do this work. He has come up with a price which seems very high, but apparently he is "sen yay" which is useful for permission and access issues. Bro-in-law is completely trusted, no commissions there.

So I won't mention the price for now, but assuming a macro-type machine is the tool what would be the day cost for one of various sizes of these.

I know the little baby ones cost 4000 per day but can be half that or less, but I think this would need a sizeable bucket. The site is a rai. A quarter or third will be cut lower and moved across to fill the wasted dip behind the present house site (the new house can then go on that. That and the terrace work on the slope.

BTW another question the earth that gets moved to the dip will be under any new building, I know, it should settle for a year or two or three. As life is short is the only alternative to pound in friction piles?

How about building on a raft?

SO I guess there are about 3 questions there!

Thanks!

Edited March 7, 2014 by cheeryble

[IMHO]

I don't think anyone can answer your first question without a full site survey...

Piles is the only smart way to build on top of fresh terraforming.

A raft?!?!?! you want it to slide away as the soft ground beneath it turns into mud?

[bbradsby]

That sounds, sight un-seen, like a lot of dirt relocation. A bulldozer would be the most efficient way, thus cheaper.

For the house foundation, unless its wood construction (not likely for new construction in LoS) or the plan is a single story compact, rectangular shape, driven piles are the way to go... unless there are large rocks in the strata, which tend to splinter concrete piles.

[cheeryble]

I don't think anyone can answer your first question without a full site survey...

Piles is the only smart way to build on top of fresh terraforming.

A raft?!?!?! you want it to slide away as the soft ground beneath it turns into mud?

My parent's bungalow I believe had a raft foundation like a big slab used for generally unsound areas I believe cos it spreads the load. Obviously a bit more expensive but maybe not too much compared to time benefit.

That sounds, sight un-seen, like a lot of dirt relocation. A bulldozer would be the most efficient way, thus cheaper.

For the house foundation, unless its wood construction (not likely for new construction in LoS) or the plan is a single story compact, rectangular shape, driven piles are the way to go... unless there are large rocks in the strata, which tend to splinter concrete piles.

Agree bulldozer first came to mind but I thought because of the cliff the dirt needs to be dragged back from it from a bit of distance.

Good point about piles could hit rock.

As to compressing newly moved dirt have I see them running over fill sites with macros or dozers presumably thinking they're very heavy but of course pressure = force/area so you would get a lot more pressure from a small imprint like a car tyre even, the whole idea of a track is to spread the load. I wonder if dirt could be compressed enough some way like this without the wait.

OTOH if one rainy season's enough we might be able to build in autumn.

What's the consensus on that TVers....is it enough?

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Edited March 8, 2014 by cheeryble

[IMHO]

Why are you avoiding using piles? They're cheap and go in reasonably fast - and as soon as they're in, your can start your footings immediately..

[cheeryble]

Are they cheap? Any example figures?

I had guessed they would be dearer, and I'm aware that sometimes they have to go very deep.

There is clearly rock not too far down on some of the site and also an area sticking out in an outcrop on the excavated land next door on the cliff side.

What is the minimum depth for these piles assuming the dirt is firm enough to hold up the cliff at an angle not far off vertical?

If it's not too far one might get away without hitting rock.

Or else.....is it OK to just hit rock and leave it at that? (Probably only modest sized one storey building.)

Thanks!

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Edited March 8, 2014 by cheeryble

[IMHO]

Piles vary in width and length, and the costs will also vary by travelling distance and the amount of piles to sink... Your engineer should be the person to advise the type of piles to be used, and devise a plan should you hit rock. Also, if your plans don't yet specify piles, the footing design will need revision and engineer approval.

As a very rough guide, expect around 4000-8000 Baht per pile completed - not including your own worker's time. One pile per footing of course.

[cheeryble]

Thankyou IMHO for the excellent information it was exactly what I asked for.

However just last night I learned it would be much better permission-wise if we went with the earth moving man and no piles as it is unregistered land.

Apparently the earth man is the man to do it as I say he is "sen yay"…..he has a lot of clout….and I learn he did the whole big hill behind so he's real.

I'd like however to just judge his (at first glance high) price and it would be very useful to know typical prices for macro+driver rental for various sizes…..or even anecdotal one-off prices posters might have paid for earth works to compare.

Part 2: It has been mentioned someone that rolling with bulldozers or macros will do most of the trick and we can build in a few months. True?

Thanks again!

Edited March 9, 2014 by cheeryble

[bbradsby]

Cost for men, equipment per day vary by location for cranes, dozers, macros, piles & pile drivers. What decent-size city are you near? Chiang Mai if memory serves.

Also, pile prices depend on size, length and strength. From the thread, it seems you don't currently have an engineered design for your foundation, so this can vary costs quite a bit. But last time I drove piles for a single story house on 2m pad + 3m penetration into undisturbed soil it was 2200 per pile + 30,000 per day for driving rig & crew. Allow 30 piles for an L-shaped three bedroom / two bath home of 150 m2, plus one-car carport.

Let me know if you need a set of drawings.

All the best,

[cheeryble]

Thanks BBeadsby for specific information I like that very much.

We am told access issues etc mean we don't want piling. (It's only going to be a chalet at this stage anyway, so piling for small building may be uneconomical)

On reflection, we now have to either

1. Rethink and place foundation pads on present undistrurbed compacted earth at the level we want, followed by possible earthmoving afterwards "around" the house position.

2. Learn good information about the wait necessary for fill (my dirt will become fill after being moved around) to settle enough for building a modest single storey structure. We've heard everything from three months to three years.....also heard the earthmoving machinery can compact enough, but wonder why everyone else doesn't do just that.

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Edited March 12, 2014 by cheeryble

[bbradsby]

For spread footings bearing on a pad, most folks here wait at least one rainy season's worth of pounding down the pad, and then have at-it. If your pad material is solid and you have a engineered design, you may get by with spread footings in lieu of driven piles.

To me, its a false economy, what with the cost of 1m deep excavation, forming, rebar, then the concrete for a footing. Generally, every crossing of floor beams receives a footing, so it quickly comes up to 30 footings for a modest three-bedroom house, and your site begins to resemble a WWI battlefield... LOTS of really big holes. Then when its all said & done, your entire investment is resting on the relative merits of the dirt pad some farmer dropped off on your site.

Me, I always design and recommend driven piles for concrete construction unless site geotech strata indicate otherwise.

Edited March 12, 2014 by bbradsby

[fatdrunkandstupid]

Why not buy a suitable block.

You can use the other block for its only suitable purpose. Growing rocks.

[fatdrunkandstupid]

Bite the bullet and hire a bulldozer. Quick and I am betting cheaper in the long run. If the guy accepts the contract it is his problem if he falls off your cliff. You do not have enough time to start this project now as wet season approaches. Wait until January, and in the interim you can shop around for the best and cheapest contractor. You can also do further research on the strata of your block.

[cheeryble]

IT also occurs to me that if I put a slight slope on new moved dirt (which I normally would to keep water from sitting near a clifftop) the rain will mostly run off rather than soak through and compact the dirt.

Hmmm….

Bradsby

thanks again for the piling recommendation but as I say there are access issues and as the land is unregistered at least staying quiet may be appropriate rather than driving piles.

BTW this will not be even a small three bedroom home at this stage possibly a large one roomer like a holiday chalet for a start with plenty of (possibly roofed) balcony so a small build with steep access may be another argument against piling. If we want to move there in future 100% instead of 35% more area can be added to we can do the layout to prepare for that eventuality.

Edited March 12, 2014 by cheeryble