Consolidation of soil

what are you placing that will require 1000 acres to be consolidated?

sir,thanks for your kind response. It is proposed to construct a 2x 1200 mw thermal power plant (coal based) in the area of 1000 acres

Consult a geotechnical or soil engineer.

I think you need to consolidate only on areas where you will build any structure. You may also need soil stabilization for service roads, driveways and parking areas.

yes sir, i agree to your suggestion that we also need to consolidate the areas as you mentioned.can electro- osmosis method of stabilisation solve the problem with in a time limit of 2 months for 1000 acers and let me know how efficient it is .

Electro-osmosis

as discussed in this website seems to be promising for consolidating contaminated soils, and especially suitable in silt and clay rich soils at a shorter period.

Aside soil consolidation, stabilizing foundation materials will be necessary for heavy structures that will be built at the site. The use of piles maybe required.

Hope this helps.

thanks for your advice. can you give some information regarding this method being adopted any where in the world for large areas.

I have no idea.

I've live in a small island and am not aware if the technology is being applied elsewhere.

Maybe what you can do is to search/contact for Geotechnical or Soil Engineering companies in your area and explain to them about your project. They may be knowledgeable about the technique or may have other methods of consolidation of your site's soil conditions.

Good luck!

A typical procedure is not to mitigate the entire area but only those within about 10-feet of the perimeter of building foundations. There are many methods to mitigate shallow weak soils (it is unlike that deep foundation will be used unless the foundation loads are very heavy and the acceptable differential or total settlements are small). Many time they design many of the support buildings to have floating slabs (reinforced to handle the settlement) and over excavate soft materials and replace with engineered soils (these can be lime treated native clays, or imported materials). Large heavy foundations, with small acceptable settlements can by constructed on Cast-In-Place or Driven Piles, it is shallow so they would be easy to install for end bearing on good basalt. There are also structural options to redesign the foundations and buildings. Also, there are deep soil replacement, deep compaction, Surcharging, and many other options. Everything is cost driven, cost of subgrade mitigations versus structural mitigations. Your best bet is to first have a rough design lay out of the building foot prints, and the proposed foundation loads, contact a geotechnical engineer, have them investigate the site, and correspond with your structural engineer to determine a cost effective approach.

I totally agree with your points. Please read post #3 and #5.

Foundation design depends on the soil condition and the costs that will be involved. It is important to do some kind of value engineering the different methods of soil consolidation/stabilization and the varying foundation designs that can be adopted for the project. You maybe able to determine the best combination at a least/feasible/affordable amount.

Vibro-floatation works well in loose soils over-lying a solid base. It is a long vibrating column that is moved into the loose soils. Google it!

You need to know the depth of groundwater. You may want to investigate the use of wicks to allow the ground water out of the soil and apply great pressures to the soil. How to apply the pressures will depend upon the final loading an area will receive. You may have a large building that may require a mat founadation. YOU WILL NEED AN EXPERIENCED GEOTECHNICAL FIRM.

And also an experienced engineer.

it depends on what the final site use will be and what level of compaction is required. the only effective way to compact to that depth over that large of an area in that short of a time period is deep dynamic compaction.

Two months is insufficient time to attempt consolidation.

Even with closely spaced vertical drains, it is unlikely that you will achieve the 95%-100% accelerated consolidation that would be necessary for building purposes. Your project will impose significant point loads to the foundations and so differential settlement will be the key issue as you are no doubt aware.

Piling to the short depth to good ground does not appear to be unfeasible nor expensive with an associated ground slab. An alternative is a cassette raft but this would probably sink under the pressure from your building unless you could dig down far enough to give buoyancy. This seems unlikely.

If you do pile, then the thresholds of your building and the services entering into it will experience differential settlement and these should be designed for. Everyone needs to be aware of these values for their design: architects, M+E engineers, road engineers etc. The geotechinal engineer should be able to give you an estimate of the changes of level anticiapted over the next few years along with an estimation of their accuracy i.e. a max and a min relative settlement.

The low SPT values would also indicate that the roads need to be carefully designed, especially if they are taking lorries of coal on a regular basis.