bore drilling procedures

Does anyone here know how the process of bore drilling is taken out and how it is related to SPT? Please give full description of the procedures or related sites.

 

[coneboy]

To Mini Eng

What are you referring to when you say "Bore Drilling"?

ConeBoy
(F.Y.I. SPT is a sampling and ground density testing procdure, while drilling is a method of advancing pipe into the earth. The two items work togeather, but I would not estimate SPT values from drilling observations)

 

[jbp]

A hole is drilled using solid-stem or hollow-stem augers to a specified depth. A split-spoon sampler at the end of some drill rods is then inserted through the hollow stem augers (solid-stem augers are withdrawn from hole prior to sampling). With the sampler resting at the bottom of the hole, 3, 6-inch increments are measured and marked on the rods that protrude out of the hole. A hammer (usually 140-lbs pounds the sampler down 18 inches. Blow counts per 6 inches are recorded. The blows for the last 1 foot are added to get the SPT. Joseph Bowles is a good source to learn more. Blow counts are then corrected for energy losses and normalized to one TSF. Corrected and normalized blow counts should be used when making correlations.

 

[Sean2]

Please note that the practice in the UK and Ireland is to count the blows to advance the tool for each of six 3inch increments, and the SPT N value is the sum of the last four blowcounts (i.e. over the last foot). The metric measurements used in the UK and Ireland corresponding with these are: 3 inches ~ 75 mm and 1 foot ~ 300 mm.

Various corrections are also applied in the UK and Ireland.