What is thixitropy?

Friction piles only work when the conditions are suited for them.

If the pile is driven to bedrock, it is not a friction pile.

A poorly design pile system gets worse when the load is applied, not better.

Some inorganic clays may be suitable with piles if friction can be developed between the pile and the soil.

Please hire a geologist or a civil engineer familiar with soil mechanics.

There are many terms which mean somethig similar but slightly different than thixotropy. Essentially thixotropy is the behavior of a material to have a declining viscocity as the shear velocity increases, such that it will have a higher viscosity, and shear resistance, when there is no motion of object in the material, but this strtength reduces as objects move. A similar effect can be observed in many sauces like catsup, where when static it holds some shape and sticks to a container, but when provided enough stress to begin moving, it breaks down and flows easily (however, this is not actually thixotropy, but one of the many similar effects).

So much of what everyone is throwing out here is from the books. Fine, all well and good. I have to say though, until you have held and tried to work with a truly thixitropic clay, you have no idea.

Case in point:
I dug some local clay in the area around Amherst MA while I was an undergrad. This clay was deposited in the prehistoric Lake Hitchcock. Everything looked nice, great plasticity, nice even distribution of particle sizes... Got it home from the field, dried the clay, slaked it, dried it back to workable consistency and figured it was ready to throw. Skipped wedging. Plopped it on the wheel and started to throw, felt good for about 20 seconds, finished centering and started pulling up and all of a sudden I was holding jello.
Couldnt be the clay of course, "had" to be me... So I wedged another lump and as I was wedging I watched the clay go from being stiff (HARD to wedge) to being a gooey mass that resembled a cross between jam and snot. Couldnt even really get it off my fingers. So I held still and it stiffened right back up. You have no idea how ODD it is to see such a thing!

Suffice to say, I tested mixing small percentages of this clay into my standard white stoneware, in decreasing amts till it was barely more than a colorant.... and it STILL had the same behaviour. Very wild.

I guess my point in all of this is that thixitropy is a very odd behaviour. Definitely not something most of us would want or expect in a claybody. But it is out there, naturally occuring throughout the world.

Enjoy!

Hi darlasrinivasarao,

A bit hard to say all people who haven´t pass over your specific experience have no idea, isn't it?

As you said, most of things "threw" is from the books... but I always thought that knowledge was in the books (or in some people who explained what in the books was).

The phenomenon you describe is within a branch of science called "Rheology" and the answer by JohnDG is quite exact and explains "scientifically" the reason of what you experienced.

Anyway I think the OP is not related with thixotropy because it seems to me don't explain the different behaviour of a pile from the moment it find high resistance and you stop, and the resistance one or several days later. I think this is more related with the type of soil and the external conditions (humidity, rain, etc.) that can "relax" the soil.

As Eriew said, Is there any geologist?

Kind regards

Tomato ketchup is an example of an everyday substance that is thixotropic. Most CR4 readers might have an idea of the properties of this fluid, without having to push a pipe through Amherst MA local clay, and without going to the prehistoric Lake Hitchcock...

As others have correctly indicated above, a thixotropic fluid has the property of reducing its viscosity with increasing rate of shear.

Hello Guest,

Another example of a thixotropic substance that is not used so much now, but used to be very popular, is hair gel - Brylcreem was a popular Brand.

As it is placed onto the hair, it liquifies, and as pressure is removed, it becomes a 'semi-solid' once more.

Kind Regards....

Hi darlasrinivasarao,

There are many methods and computer programs available for this purpose. An acceptable hand method is included at the end of this appendix.

I think your present answer is directly related with the OP, and seems well supported.

Please, don't take offence, I'm a jester, but... where is the "appendix".

Don't tell us that you make a copy/paste from a book!!!

Anyway, here's my GA.

Cheers

Can you give some idea about your "There are many methods and computer programs available for this purpose. An acceptable hand method is included at the end of this appendix", for my referance, and don't do copy and paste,

Of course not.

Please don't get angry, I was joking because your first answer in which you seemed to accuse all previous posts were about things found in books and not in direct experience.

Anyway the phrase "There are many methods and computer programs available for this purpose. An acceptable hand method is included at the end of this appendix" is not mine... you wrote it first..

I present my apologies if you feel insulted by my joke. (Even jesting, I honestly rated your post as "Good Answer")

darlasrinivasarao, Kwetz was merely quoting from your Step 2 in post #7.

I, too, would be interested in knowing to which appendix you are referring in your term "this appendix". The post itself cannot be described as an appendix, as it is not appended to anything.

Please clarify.

All structure investigation reports shall include an appendix, containing the following

information:

a. Report of Core Boring Sheets.

b. Report of Cone Sounding Sheet.

c. Data logs or reports from specialized field tests.

d. Laboratory test data sheets.

The following are examples of what should be provided.

1. Location, elevation, Maximum Load, Core Length, Core Diameter,

Moist Density, Dry Density, Splitting Tensile Strength, Unconfined Compressive

Strength, Strain at 50% of Unconfined Compressive Strength, Strain at Failure and

Corrected Tangent Modulus (the slope of the linear portion of the Stress vs. Strain

curve)♥

2. Gradations: Location, elevation, test results.

3. Corrosion Tests: Location, elevation, test results.

e. Engineering analyses and notes.

f. Copies of actual field boring logs with all drillers' notes and hand written

refinements, if any

g. Any other pertinent information.

Ok, but what does that have to do with:

" Determine (ing) ... the overburden pressure increase, Δp, versus depth due to the approach embankment fill... (using) an acceptable hand method (which) is included at the end of this appendix."

??