Is there such a thing as too much fill??

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Is there such a thing as too much fill??

Postby sakchai » Tue Jan 11, 2011 1:06 am

Hopefully I'm not asking a repeat question here. Did a search of the "land" thread and came up short. We have 0.8 Rai of land on a canal in Salaya area outside Bangkok. The area floods every year to some extent and has really severe flooding about every 5-6 years. I would like to build the land up at least a meter above the watermark left from the last severe flood. The land is currently dug out and flooded for lotus farming so we will need a meter or so to get it up to the level of the surrounding land, then a meter to build it up to the level of the watermark and a third meter to reach my comfort level. Is there such a thing as too much fill? Would we have to fill in stages to allow the land to settle properly? If not, how much time should it settle before we start to build?
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Re: Is there such a thing as too much fill??

Postby geordie » Tue Jan 11, 2011 6:16 am

there is no limit as to how mutch fill you have other than how mutch dirt you are prepared to buy and how long you are prepared to wait for it to settle
I built on fresh fill but had to dig through it to solid ground for footings somthing i would be inclined to do even if the fill had been there a year or so although i understand people have done it in less
to fill 3 meters is a lot of settling down and compacting so you would have to layer it and compact the layers
an option would be build your footings first and raise your pillars to the desired floor height
at the three meter mark then raise the garden gradually
personally i would raise it one meter above the previous high for the house and parking but would not go mad on the garden raising it maybe 300 mm above the previous high risking a 1 off flood maybe but think of how big an area floods to need that extra meter??? then ask are you wasting time effort and money
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Re: Is there such a thing as too much fill??

Postby canopy » Tue Jan 11, 2011 8:11 am

You could just do it the Thai way: dump and live with the consequences. I've seen a house built on 1.5M fill on a rice paddy and the foundation is pulling apart and the walls are cracking. Those problems developed almost immediately as things get worse. Or you could do it right. Spread 1/3rd meter fill at a time and use a roller to compact it. Dump and roll doesn't work where you dump it all at once and compact only the top. Neither does waiting for the soil to compact by itself. And you don't want fill that contains topsoil or organic material. In a case like this, probably worth having an engineer come out and specify footings if a solid foundation is of importance.
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Re: Is there such a thing as too much fill??

Postby pattayapope » Tue Jan 11, 2011 8:46 am

It seems from your post you are trying to organise this from far away so it may be very difficult to get the back fill done properly. Generaly back fills here are done with dumper truck and tractor which does not do any compacting. The only time I have seen compacting done here is on road works or high dollar construction projects. If you can drain the lily pond and clean it out rather than just tipping soil in directly that would be a good start but as canopy says it needs to be compacted in layers generaly no more than one 30 cm thick with a heavy vibrating compactor. I would say that you will have no choice but to pile the foundations.

To do it right will be costly to hire the heavy equipment but it will save head aches later if you build on poorly compacted soil. Did you think about keeping the pond and build up from this so your house is on stilts and just back fill a small area for car parking ect.
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Re: Is there such a thing as too much fill??

Postby MGV12 » Tue Jan 11, 2011 9:34 am

My neighbour raised his land two metres by just dumping and spreading [the Thai-way as canopy says] and had to wait four years to build on it ... and that was from dry paddy field ... mind you his 'dwelling' is a 1000M2 monolith! As suggested, piles would do the trick but can be quite expensive as fredlk will testify. I would be inclined to consider initially working on raising the dirt level under the footprint of your house as that is the only area where solid compaction is essential for the build. You would only need to raise one and a half or two metres maximum ... of your three total metres ... to the position that your post pads will sit for the build to commence .... then the rest can be done more at leisure and with the assistance of Nature. Hiring heavy equipment doesn't come cheap anywhere due to the cost of transportation as much as anything but it's worth seeking out the nearest road-builder or commercial developer and see if they would hire you a heavy vibrating roller for a few days and compare the cost with driving piles ... after all ... you are going to have to raise the dirt even if you drive piles. With the heavy roller on site and a bladed tractor [which is always available locally] you could call in the fill subsoil one truck after another ... with the blade spreading it thinly [the thinner the better] and the roller continuously compacting it. A few days at most and you would have a solidly compacted area on which to shutter up and pour your post pads.

If you want to be totally sure an inspection from a qualified geological engineer [maybe available from a local university at reasonable cost] would always be a good idea as local conditions ... the substrate under your current dirt level and the fill subsoil available will vary from location to location.

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Re: Is there such a thing as too much fill??

Postby BKKBILL » Tue Jan 11, 2011 10:20 am

Every build in BKK is done with friction piles as this area can subside as much as five cm per year. I would assume Salaya would be similar. As canopy and MGV12 recommended probably worth having an engineer come out get the OK then build on piles at the height you want then just infill at your leisure. Compaction of three meters can be a very expensive undertaking.
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Re: Is there such a thing as too much fill??

Postby otis-a » Tue Jan 11, 2011 10:33 am

geordie's method is simple; with caviet: u build is in a flood plain- what this means is the soils are likely to be unconsolidated perhaps with high clay fraction
the more weight added to these soils the more pressure acting to dewater- & dewater = settlement
clear ezamplers r the big easy and bkk - the cities sink under their own weight or squeeze a sponge with different forces and c water removal
a very simple rule - if u remove a weight of soil equal to the weight being supported- settlement will only happen if u build in quick sand- otherwise the 10k years of settlement since last ice age has done the work 4u-
how much will your structure weight? Well have u a cost estimate of the materials? All materials have a density and volume or weight- ditto for soil in place
alt 2
use piles
alt 3
go with floating beam foundation

in your situactikn- i'd hire a proper soils/foundation engineer- an u r talking to an engineer who aced these subjects- but my engineering licence and 30+ years experience cover another speciality- ensure the staff have worked the river basin in question
alt 4 use closology
for my build the builder (wif's father) has made several builds in the area & without issue- the method used here was to set column supports 1/2m under existing terra firma & fill 1m above xtf- caviet- each location is likely to have specfics
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Re: Is there such a thing as too much fill??

Postby jazzman » Tue Jan 11, 2011 1:18 pm

We never build on fresh fill dirt, or even some that has been allowed to settle for a while. We always go down deep enough with the footings that the concrete base slab is in the original hard dirt. Much over two meters this gets unpractical. Then you build on piles. Driving piles is a bit more expensive of course, so one either has to accept the extra cost, or build a smaller house :wink:
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Re: Is there such a thing as too much fill??

Postby MGV12 » Tue Jan 11, 2011 5:38 pm

To pile is without doubt the safest solution .. no argument if you are in an area prone to settlement or with a clay substrate that will be subject to expansion and contraction as the seasons pass .... and especially if you are not an experienced builder and decide not call in an expert to confirm what is needed. It is however an expensive solution and in your circumstances does have its drawbacks.

The reason I suggested considering an alternative is that I always try to look at the bigger picture ... in my mind it's not simply a case of whether you should pile or not ... if upon qualified inspection of local conditions you have a choice. You are intending that your final dirt level will be three metres above current level and your ground floor presumably higher still. If you pile you will either have the impractical situation of your builder working up ladders or scaffolding even for the ground floor or you will have to raise the soil level to suit. This amount of uncompacted fill will create difficulties during the build [especially in the rainy season] when heavy trucks are trying to deliver and even during general manoeuvring over the freshly dumped soil ..... see the nightmares on Max & Bee's thread as an example of problems with bogged-down trucks on a far lesser fill: viewtopic.php?f=3&t=1970&p=16509&hilit=truck#p16509 You would also be prevented from landscaping immediately around the house for some time while you wait for everything to settle down ... if you decided on any level of compacting to avoid these problems you are part way towards doing a full compaction job.

As with many questions posed on CTH there will be differing opinions but always make your own decisions based on qualified expert advice. You will want your house to stand the test of time and there is no way of knowing the credentials of any of us posting well-meaning advice here .... its just opinion ... made with the best of intentions

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Re: Is there such a thing as too much fill??

Postby Maseratimartin » Wed Jan 12, 2011 2:03 pm

I hear from people around BKK that in BKK area you should always use piles. BKK is wet land....the changing water levels affect the stability of the ground.
In BKK the soil will never saddle....
I would take a good engineer...they will test your ground and accordingly tell you what to do.
I estimate with piles drilled or ramed in the ground....on top a solid double layer rebar reinforced concrete slap you could be safe.

Or: Look to the Netherlands....they have very nice swimming homes there..... :mrgreen:

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Re: Is there such a thing as too much fill??

Postby geordie » Wed Jan 12, 2011 8:04 pm

there is an alternative shown here by developer 3d with the waffle pod slab
again i would be inclined to place it before any fill and extend colums up too floor level
my own thoughts would be to look at creating a cellar and have the benifit of a cool area permanently
The other concern which JAZZMAN flagged was that the bungalow now becomes two story because of the depth of the base from floor given that it has to have a fill at some point
build like the egyptians raise a dirt platform around the house to work off and level it out over the garden before the rains start allowing it to compact
With regard to proximity to bangkok and a need for piles the expert on that i rekon is bill he probbably knows how far away you are but having seen the black sludge that comes out of excavations around and in BKK i think i would dig a couple of meters down and see if there is any solid below where you are going to build
Alternately have a look locally and see if they have had problems and used piles
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Re: Is there such a thing as too much fill??

Postby BKKBILL » Wed Jan 12, 2011 10:53 pm

Afraid not geordie Salaya is about 10km from me but under ground is a whole different story.

As the graft shows soft grey clay could go down ten meters.

Years ago a lot of farmers were stripping the paddies and selling clay to building sites in BKK. After that holes held water so very well lotus farming became the norm.

Money of course drives everything here.

I think most posters have it right. Get a proper soils/foundation engineer as you will not be able to compact the clay if that is what is under Salaya. Just to much uneven movement. So if deep clay friction piling is the way to go. I understand this clay extends north past Singburi.

Cracking of masonry buildings built on reactive soils is a common issue of clay soils of significant depth underly buildings.
Reactivity refers to the tendency for the clay soil beneath the footings to shrink and swell with changes in moisture content which can lift and lower the building. The major factors influencing this are: • The ability of water to reach the clay material beneath the footings;
• The composition of the soil; • The depth of the soil; • The effect of trees.
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Re: Is there such a thing as too much fill??

Postby geordie » Wed Jan 12, 2011 11:30 pm

My 65 plus year old house is on reactive clay on strip foundation
A lot of london is but a large propotion of london was built with lime mortar it never really sets although it is strong enough to build a wall with good brickwork well bonded and flexible
with clay in the summer it shrinks and winter it heaves/swells
My aim would be spread the load as best possible over a large area and build on a raft the aim being it will move but if the raft is a sucsess it will move as a whole so not destroy your home
One of the problems i had installing my cellar was that the depth i was digging to although in the same clay it would react differently to clay at the surface i was causing a hard spot under the house the way around this was to allow the cellar to do its own thing within the existing footings so theoretically the house does not rely in any way on the cellar as a support but should move around independent a bit like sliding a box of matches open pretty mutch the same as was suggested to rodger for his indoor pool
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Re: Is there such a thing as too much fill??

Postby Max&Bee-in-CM » Thu Jan 13, 2011 12:43 am

MGV12 wrote:This amount of uncompacted fill will create difficulties during the build [especially in the rainy season] when heavy trucks are trying to deliver and even during general manoeuvring over the freshly dumped soil ..... see the nightmares on Max & Bee's thread as an example of problems with bogged-down trucks on a far lesser fill: viewtopic.php?f=3&t=1970&p=16509&hilit=truck#p16509 You would also be prevented from landscaping immediately around the house for some time while you wait for everything to settle down ... if you decided on any level of compacting to avoid these problems you are part way towards doing a full compaction job.


Ah... such happy memories... thanks MGV12... but seriously yes, we have had many bogged trucks and tractors with 50cm infill, I can imagine a truck being swallowed up into 3m soil that is not properly compacted.
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Re: Is there such a thing as too much fill??

Postby pattayapope » Thu Jan 13, 2011 8:38 am

Sakchai

Your head must be spinning with the questions and answers from different members, are you starting to get cold feet on the implecations of fill and later subsidence or are you going to go ahead with the suggestions. There have been regular reports of Bangkok being underwater in a few years time maybe you should condsider a new piece of land with less problems a little further out of town. Salaya is near Nakon Pathom if I remember correctly and I worked there briefly a few years back and the whole area is very low and the infastructure is in poor condition from what I remember.
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