Diameter of borehole?

[sdz]

What borehole diameter is usually required to get a soil profile and do SPT tests during a geotechnical investigation?

 

[GeoPaveTraffic]

The diameter varies considerably depending on the type of equipment used. In the mid west US, shallow holes are usually done with one of the following:

3.5" O.D. solid flight auguers

3.25" I.D. hollow stem auguers

or

4.5" I.D. hollow stem augers.

The O.D. on these hollow stem augers about about 8" and 10" respectively.

There are also larger hollow stem auguers.

For deeper holes you have mud rotary drilling with bits starting at about 4" diameter and going up.

 

[muuddfun]

I am generaly using an 8 in O.D. hollow stem.

 

[msucog]

what do you mean by "get a soil profile"?

 

[fattdad]

2-1/4 in hollow-stem augers are the minimum auger for SPT testing. The boring diameter is just about 4 inches larger (i.e., total diameter of 6-1/4 in).

Mud rotary will be different.

f-d

¡papá gordo ain’t no madre flaca!

 

[sdz]

Thank you all.

 

[BigH]

Of course, there are always the non-HSA methods of using casing. We used to use B casing for SPTs although N size was more preferrable. B size is a bit tight. See Ackers Drilling web page for information on standard casing sizes and core barrel sizing. Also there is the method of solid stem augering with is good in firm to stiff clays.

http://www.ackerdrill.com/about.html

http://www.ackerdrill.com/augers/octparts.html

http://www.ackerdrill.com/augers/conventional.html

http://www.ackerdrill.com/diamond/reference.html

http://www.ackerdrill.com/supplies/rods.html