Geosense VW PIEZOMETERS, Инструкция по эксплуатации

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Version 1.4 May 09
1. Before drilling the hole it is important to
ascertain the depth at which the piezometer is
to be installed. An indication of the ground
conditions may also be helpful.
2. The borehole should be formed to a depth of
approximately 500mm below the intended
elevation of the piezometer tip. If a Bentonite
plug is required at the base of the borehole, it
will have to be drilled further to accommodate
the plug.
3. Before commencement of installation, the depth
of the hole should be re-checked and the
procedure you intend to follow should be
confirmed with the engineer and discussed with
the driller.
4. Confirm that all materials are available ( filter
sand, Bentonite pellets or balls and backfilling
grout ). The piezometer to be installed should
be transported to the borehole locations in a
container of clean water ( see section 5.1.13 ).
(Continued on page 19)
5.3 Installation Procedures - Boreholes
Each piezometer installation is different and requires both common sense and a gen-
eral understanding of the sub-surface conditions. There are many approaches to
piezometer installation and, in addition to these broad installation guidelines, MGS
Geosense are committed to providing technical support to help engineers and techni-
cians tune their procedures to match particular site conditions and requirements.
Boreholes can be flushed with clean water prior to installation operations if excessive
sediment remains in suspension.
Each piezometer is labelled on the cable, however steps should be taken, perhaps
with the aid of coloured tapes, to mark the cable so that there is no confusion over
piezometer identification. This is particularly important for installations where more
than one piezometer is to be installed in one location.
5.3.1 Cased boreholes.
When forming a borehole for instrument installation, it is sometimes necessary to use
a temporary steel sleeve or ‘casing’ to hold the hole open during drilling and installa-
tion operations. The following describes a series of steps that could be adopted to
carry out a piezometer installation in such a fully cased borehole. This procedure can
be adapted where boreholes are only partially cased.