Generally borehole logs include both SPT 'N' values and a breakdown of the
seating and test blows, and I would be surprised if there is a GI contractor
that does not provide this information in the final factual report.
Whenever we receive a factual report, we check among other things that N
values were added up correctly, and yes mistakes are sometimes made.
Regards
Mahmoud I Alsayed
-----Original Message-----
From: David Toll [mailto:[log in to unmask]]
Sent: 02 March 2001 10:17
To: [log in to unmask]
Subject: Re: SPT
Dear Alex,
In my experience, the seating blows are recorded on the drillers' log but
are not reported in the site investigation report. As you suggest, it is
useful extra information which can be used when assessing the validity of
the SPT values observed, particularly when unusual values are seen. I would
say that it is good practice to have that data, but I wouldn't have felt
that the lack of that information invalidated the test result itself.
Regards
David Toll
-----Original Message-----
From: Geotechnical Engineering Email List
[mailto:[log in to unmask]]On Behalf Of Alex Carson
Sent: 02 March 2001 9:58 AM
To: [log in to unmask]
Subject: SPT
In the British Standard for site investigation it states that the initial
penetration of the hammer should be recorded before the start of the test.
The HA (Highway Agency) checking engineer is making statements that "the
site investigation is not in accordance with British Standard " because we
have not recorded the initial penetration. As far as I am aware the value is
not normally recorded unless it is significant. The lowest SPT 'N' is 25 .
I would be grateful for comments from the group.
Alex Carson
Babtie
Telford
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