Soil Parameters for jet-grouted Alluvium Soil

[onuro]

Does anybody know were I can find soil parameters (internal friction - cohesion - bearing capacity ...) for jet grouted soils?

 

[BigHarvey]

You take the problem the wrong way. Try to estimate your needs in function of your loading and then derive ( or have it done by a specialized contractor ) the jet grouting parameters to obtaine these values ( cement content and energy )

 

[onuro]

Thank you for the answer,
As per the stability analysis for a small dam with 15 m high;
the following soil parameters seem to be enough:
bearing capacity: 300 kPA
coefficient of frinction: 33 degree
cohesion:100 kPa

At this point, how can I specify the jet grouting parameters?
I read some papers related with the subject, they are not clear enough.

A good referance is better answer.

 

[BigHarvey]

All depends on what is looked for : improvement of mechanical characteristics or watertightness. For watertightness, I personally believe it's not a reliable solutions ( many bad case histories ). For the mechanical side , you must specify a column diameter and a strength value for the end product. You can check the diameter with excavated trial columns if they are
not too deep or with geophysical methods ( electrical cylinder mainly). For the strength, you just sample the spoil which has the same composition than the column and you test it just like grout or concrete.

 

[dgillette]

Are you set on jet grouting, or are you exploring alternatives needing cost estimates? Most of the real expertise in jet grouting belongs to the contractors who do the work, and a few consultants who do it a lot. All the contractors have their own proprietary equipment and methods. If by "parameters" you mean cement content, column diameters, etc., the answer is particular to the soils in question and the contractor's tools. Test sections prior to bidding or prior to production grouting are common and very helpful, and for a small dam, the cost of test sections, equipment mobilization, quality assurance-quality control, and other startup tasks could make JG less attractive.

Remember that for a dam's stability, you may need the jet grout to provide lateral resistance in addition to bearing capacity, which requires high strength on horizontal surfaces under the slopes. Therefore, any continuous weak horizontal layers could be a problem for a dam, even if they are not such a big deal for other structures that just need bearing capacity or control of settlement. This is not as easy to accomplish. You may also need good column overlap to be able to mobilize the lateral resistance (complementary shear on vertical surfaces).

Use Google etc. to search for papers on jet grouting at Tuttle Creek Dam, Kansas, and Wickiup Dam, Oregon, which were modified for earthquake problems.