Building on a Swamp

[JMLeng]

We are consulting on a project to build multiplex houses in northern Ontario, near St. James Bay. Assume that the soil conditions are very poor as the water table is one foot below grade. It is unreasonable to excavate to good soil and backfill with good material. Piles are out of the question because the equipment is not available in the region. The structures are single story wood construction with crawl space. Has anyone ever designed a foundation for similar applications?

 

[msquared48]

Get a geotech for a project this big with such poor bearing.

Surprises with the excavation costs can make or break a project.

Mike McCann
McCann Engineering

 

[GabionGuy]

It may be possible to build large area foundation platforms over the soft soils using very high strength (800kN/m ++) geocomposites. The ParaLink products from Linear Composites are used elsewhere in the world to create bearing pads over very soft soils for very heavy loads (ore stockpiles, liquid storage tanks, etc.).

If you are in Canada, contact Maccaferri Canada - They have done work in Northern Quebec were the geocomposites were used over soft clays. They should be able to help with the design.

 

[kelowna]

It is not my field of expertise, but I remember that at University they said that for bad soils it was best to excavate and remove as much material as weight the future structure would impose on the ground. That way, the soil balance would remain unchanged and therefore no settlements would take place.

Since the water table is so high, I assume that this is not an option for you, is it?

 

[BigH]

There is a good book - old but true - called the Muskey Engineering Handbook from the National Research Council in Canada. Name escapes me know. But I am sure that you will be able to find solutions to your problem there. Don't know how deep your muskeg is but there is a concept known as the rollling surcharge - where you start out with a fill at one edge - make it higher at the end and force a failure which will displace the muskeg - like mud waves - you then build this out. It is explained in Tschebotarioff's book (1951) and is part of a Michigan study in 1947. Good concept. Has worked on many sites. All else fails go to some old hands in the area and ask them how they built it (Golders comes to mind - but the older guys, most likely).

 

[ACtrafficengr]

Have you looked into geopiers (

http://www.geopier.com)?

"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

"I'm searching for the questions, so my answers will make sense." - Stephen Brust

 

[bimr]

Muskeg Engineering Handbook is correct.

 

[stanier]

George Stephenson built the Liverpool to Manchester railway across swamp. One of the greatest engineering feats of the 19th Century.

You can read of the difficulties and solutions in the history books. The Institution of mechanical Engineers has available a library full of documents on their first president.

A book called the George Stephenson Letters documents some of the details.

Geoffrey D Stone FIMechE C.Eng;FIEAust CP Eng

http://www.waterhammer.bigblog.com.au