piling in peat

[2V]

Hi,

What are the issues of iron oxide reacting with soggy peat ground conditions whilst piling?

Cheers,

2V

 

[MRM]

Hi 2V,
Are you talking about corrosion of steel pipe or H-piles in peats? If so, it's a concern, but in most cases not a huge one unless conditions in the soil are extreme. Potential for corrosion increases with several factors such as pH and resistivity to name two. The more electrically conductive the soil is, the greater the chance for corrosion, which makes sense; ions can move around in a highly conductive medium. Strong acids or bases can also increase the chances. I believe high sulfate and/or chloride concentrations will also contribute.

It would be a good idea to look around and see if it tends to be a problem in your area. Normally, when there is a concern, most piling designs will call for thicker shells for a pipe or a stout H-pile section, (or another type of pile altogether). Most of corrosion I've ever heard about was perhaps an 1/8" (reduction in steel pile thickness) over 50 years or more (for my area in Michigan, possibly not applicable to your area). Although peat bogs will vary in chemical and electrical properties even in the same area.

Cathodic protection is another option to limit the corrosion of underground steel structures like piles, however these systems are expensive and usually tricky to set-up correctly unless very skilled individuals install them.

Remember to consider the length of time a facility will be in operation. Unless we're talking about a monumental structure in ancient Rome, most life spans for "permanent" structures are maybe 75 years, maybe more maybe less.

I would contact an established geotechnical engineer in your area-one who's been around a while. Some of them are sometimes around long enough to go through an entire design life of a structure if you're lucky! In that case, they'll tell you first hand! I'm sure they will have an opinion that considers "area specific" information for the soils in your area that I couldn't possibly know.