Soil Sampler

[sc]

My firm conducts site classifications works for proposed buildings. The aim generally being to establish a basic level of soil composition and subjective soil strength. We currently do this by obtaining soil samples using a motorised auger. The problem with this is that it does not obtain an &quot;undisturbed&quot; sample for assessment, hence soil strength is only a conservative knowledge based guess.<br>
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I have been looking for a relatively portable core sampler as a means of obtaining a &quot;better&quot; quality sample and before anyone suggests it we have client and public authority needs that prevent the use of a backhoe to excavate a hole.<br>
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Can anyone help me with a company that may supply or use a portable core sampler?

 

[bb29510]

check into drilling equipment and look at the Split spoon. it is a 24 inch tube which is driven into the ground using a 150lb drop hammer. I know it sounds big but, look in a drilling catalog and see if you can adapt. They make portable rigs.

 

[TAC]

Spilt spoon samples are still considered to be disturbed samples because of their relatively small diameter. A Shelby tube would provide a better undisturbed sample if you need to perform soil testing and soil disturbance is important. The same type of equipment as described in the previous post would be required. The Shelby tube is just a different type of sampler.

 

[Geoinvestigate]

Check Out Carl Hamm UK's Web Site at <A HREF="

http://www.carlhamm.co.uk"

TARGET="_new">

http://www.carlhamm.co.uk</A>

as they specialise in window and windowless sampling along with mini drilling equipment.

 

[prunty]

Shelby tubes are best suited for soft cohesive soils (they tend to crumple in stiffer soils). Perhaps in-situ tests may be more appropriate to your needs.......i.e. vane shear, pressure meter, dynamic cone penetrometer, etc. - good luck<br>

 

[GeoEng]

If you are asking this question consider employing a geotechnical engineering firm to do this work for you before you get into trouble.

 

A simple practical way to get undisturbed samples (cohesive), is to auger up to depth followed by ramming a shelby into the soil by hammering or a backhoe bucket pressure. Use this to also recover by first twisting the shelby rod to break continuity of soil then pull up. A split spoon is used for disturbed samples.
Best of luck!

 

[KAM_imported]

First off, if you are not a geotechnical engineer, you could be getting yourself into trouble. Second, you cannot determine shear strength from an auger sample, only soil type. Lab testing data in augered samples is also of limited value due to the mixing that occurs as the soil is sheared. You need some type of penetration test (either the Standard Penetration Test, or Cone Penetration Test)or other in-situ test (Marchetti dilatometer) to reliably estimate strength and compressibility. In general, the less the degree of disturbance to the soil, the more accurate the derived soil strength and compressibility parameters will be. There are small, hand-held devices that allow sampling and pentetration testing without mechanical assistance, but these are of limited value. Consult some of the larger soil testing equipment suppliers (Brainard-Kilman, Triggs Technologies, Inc., Tecnotest USA, Inc.,etc.) for product information.

 

[sc]

Thanks to those who helped.

We have found what we require via an mining equipment supplier. Small portable ute mounted rig with a 4 metre depth capability and a split tube. Not exactly 100% suited to the job but it will suffice to satisfy the relevant Australian Standard and Building Code.