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Author:
Barney Brill
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2002-12-02 |
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We are loooking for inforamtion as to how wet soils are stabilized economically in the US and Europe. Locally lime or other chemicals are used. Is there an alternative? Are there mechanical systems available to dry the soils?
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Follow-up:
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Author:
Shane Jarvis
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2005-05-15 |
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I'll make an assumption here, that you are looking to improve the strength of a layer of soil that has a low CBR. This is typically a road construction application.
If a low CBR is encountered at subgrade level, there are two alternatives, dig up 300mm or so and replace the layer with an imported road base material. The other method is improving the soil itself, and there's a number of ways to do this.
You can employ the stabilization machines that pulverize the ground up to 400mm below ground depth, lime or cement can be used, with cement having to be compacted and trimmed within a few hours, and Lime within 24 hours. Both additives require a fair bit of water to work effectively, and any water that isn't part of the hydration process usually evaporates when the cement or lime hydrates and heats up the soil. Lime is better for drying the soil.
I'm in Australia, and lime stabilization is quite popular here as a cost effective method of improving the CBR of crappy clay subgrades. I'm pretty sure the romans used the technique too, so it's not exactly new technology.
The other method for stabilizing the subgrade is to use a geogrid. This can be cheaper, and it certainly is faster to incorporate a geogrid, than remove and replace, or to establish the plant to incorporate lime into an area of poor soil.
But all these solutions have their problems, an incorrect geogrid will effectively do nothing, lime can leach out over time, or in some cases, worsen the CBR of the soil (personal experience on marine muds), and cement can harden before it can be compacted properly.
Food for thought!
Shane
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Subject:
Soil stabilization techniques 