Project: Station Cycle Links, Durham
Project Number: E7894
PROCEDURE FOR INSTALLATION OF VIBRATING WIRE PIEZOMETERS
1.0 SCOPE
To define the procedures for installation of vibrating wire piezometers.
A vibrating wire piezometer provides the pressure of the groundwater within a response zone
based on the frequency of the vibration of the wire in response to the tension on the wire
Procedures for vibrating wire piiezometer monitoring are covered separately.
2.0 DEFINITIONS
Vibrating wires piezometers are to be installed in accordance with the manufacturer’s
instructions and BS5930:2015 Section 52.10
The boreholes are to be constructed by the following methods;
• Dynamic sampling boreholes
Confirmation for each VWP will be provided to Dunelm by AECOM at the time of installation.
3.0 RESPONSIBILITIES
• The Supervising Engineer shall be responsible for issuing instructions to the Lead Driller
for each relevant drilling unit and having the required number of VWPs ready for
installation prior to the borehole being completed.
• Installation shall be carried out by a competent person who will be responsible for
producing the appropriate records and obtaining a grout sample.
4.0 PROCEDURES
4.1 Dynamic Sampling Boreholes
Steel lining casing will be advanced during boring as necessary to maintain stability of the
borehole.
The boreholes will be terminated in accordance with the Contract Specification and instruction
from AECOM.
Sampling will be carried out as required in accordance with the Contract Specification.
On completion of the borehole to the scheduled depth and confirmation by AECOM the
borehole instrumentation will be installed as instructed by AECOM.
4.3 Vibrating Wire Piezometer Installations
4.3.1 Components
The basic design of the VWP installations will comprise the following:
• Vibrating wire piezometer and cable
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• 19mm plastic HDPE pipe to the base of the borehole
• Cement : bentonite grout for the whole depth of the borehole (or in accordance with the
specification)
• Multichannel data logger
• Gas barrel cover protective headworks.
Pipe and wire can be cut or joined to length on site to suit the required installation depth.
4.3.2 Installation Procedure
The target depth of the vibrating wire piezometer will be instructed by AECOM immediately on
completion of the borehole.
A VWP will have been previously submerged in water in accordance with the specification
and manufacturer’s instructions and base reading will have been taken.
Temporary casing is to remain in the borehole until the VWP is installed.
The appropriate lengths of 19mm plain pipe, will be lowered into the borehole with the VWP
inverted and taped / cable tied at the target depth, the wire will be cable tied at intervals up
the length of the 19mm pipework to the top of the borehole. With the pipe and VWP in place
the borehole can be grouted up from the base using a tremie pipe.
Casing is to be removed in stages during grouting and care is to be taken to ensure the VWP
does not move out of position during casing extraction and that any excess wire is coiled
inside the casing. The grout mixed to be used will be in accordance with the Contract
Specification.
Calibration and base readings are to be carried out in accordance with the specification and
manufacturer’s instructions during the installation process using a hand held computer or read
out display.
The installation will be completed with a multichannel data logger and protective headworks
as specified.
An onsite barometer will be required to be installed on site, this will be wired into the
multichannel data logger and stored within the headworks of one of VWP installations.
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