Bog-matting is designed to stop machinery sinking so far into soft ground
that it ceases to function. It does not stop the machinery sinking, it stops
it sinking as far as it would without the matting...and, as others have
observed, it can make a real mess of the ground on which it is laid.
I assume that it has been suggested to you that the use of bog-matting will
allow something to happen above 'buffered' archaeology, leaving it
un-disturbed?
The key factor is the nature of the ground over which it is proposed to pass
- if it is at all soft, bog-matting/flexible timber track will just squelch
your 'buffering ' down into your archaeology, especially at the edges, which
will sink more than the centre and twist slightly....
Another problem with using bog-matting is that once it is removed, the
ground-surface has to be ripped, to reduce the compaction, before the
top-soil is put back, so you need to ensure any buffering used is permeable,
so as to obviate ripping.
Our experience of using bog-matting as temporary protection for archaeology,
comes from pipeline construction work. The standard option for pres in situ
is to keep the machinery/ traffic off the site, or excavate before the
traffic passes......so, usually, where there is archaeology within the
working width, mitigation means excavation.
However in certain desperate circumstances, provided the ground conditions
are right, (eg. dry/well-drained solid ground, as found on certain types of
slope or on ridges, and after a dry spell) it may be possible to use
bog-matting and ramped buffering to protect certain types of remains, to
allow machinery to pass by. I would see this as a means for one-off passage,
not a method to create a track for repeated use by site traffic, or on soft
ground etc etc. and I would have to be certain that all the alternatives
were less attractive.
If you are not contemplating the use of bog-matting for passage of machinery
or vehicles what is it for?
I would be interested to know if anyone has used the cellular geo-textiles,
that are designed to spread loadings for roads construction, for passage of
construction machinery as part of pres in situ.
Annie Given
NI Sites and Monuments Record
Environment & Heritage Service: Built Heritage
5-33 Hill St
BELFAST BT1 2LA
tel: 028 9054 3013 fax: 028 9054 3111
[log in to unmask]
www.ehsni.gov.uk
-----Original Message-----
From: Kidd, Sandy [mailto:[log in to unmask]]
Sent: 30 April 2003 15:04
To: [log in to unmask]
Subject: Re: Use of bog matting
Some research was published in Antiquity in the mid 1990s based on
experience
in the States on pipeline construction (I don't have the reference to hand
but could get it for anyone who is interested). The conclusion was that
provided its carefully done and covered by a rock blanket it ought to work.
But of course it depends on what is being protected - a few deep cut
features
may be OK but I am not sure I would trust it on a shallow cemetery. Also,
there is always the problem that what engineers say they will do and what
actually happens are not always one and the same....
Sandy Kidd
-----Original Message-----
From: Mike Shaw [mailto:[log in to unmask]]
Sent: 29 April 2003 09:16
To: [log in to unmask]
Subject: Re: Use of bog matting
Something similar was done in Northants around 10years ago on a scheme for
widening the A45. I would have thought that this was more paying lip
service to preservation rather than actually doing so. The process of
stripping the topsoil off is likely to be damaging in itself and then
placing matting over it would alter the ground conditions with the potential
for further damage and degradation. I have no hard facts though.
Mike Shaw
----- Original Message -----
From: "Lee White" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, April 28, 2003 4:37 PM
Subject: Use of bog matting
> Dear All
>
> Can anyone give me their opinions regarding the use of "bog matting" (and
by
> this I'm presuming it to mean geotextile matting) and its effectiveness
(or not
> as the case may be) when placed on a buffer material above archaeological
> features. In this particular instance the topsoil will have been
stripped.
>
> Thank you!
> Lee White
> _________________
> Lee White, Assistant Archaeology Officer
> Archaeology Section, Cultural Services
> Durham County Council
> Phone: (0191) 383-4212
> Fax: (0191) 384-1336
> Email: [log in to unmask]
>
>
>
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