Measurement for monitoring, probing and recording evidence - Tunnel Engineering: Basics and Additional Services for Design and Construction - page 140

Systematic data logging. Since almost all functions of a tunnelling machine are controlled
electrically or electro-hydraulically, the relevant variables can be measured and processed digi-
tally. Complete logging of the machine data is the state of the technology for modern shield
tunnelling machines. 200 to 400 various pieces of machine data are recorded at intervals of 1 to
10 seconds, the momentary values. This produces 1.7 to 35 million data records per day, which
can be automatically collected into average and final values for each advance cycle.
Separately from this, it is also usual to log extensive geodetic and geotechnical data as the
tunnel advances. Although this is still often performed manually, resulting in very long
and variable intervals, measurement robots have already been introduced on some more
recent projects (for example the tunnel under the Pannerdensch Canal, Netherlands) to
record defined measurement points automatically and transmit the data digitally.
In addition to the machine data and the geodetic data, data is also recorded at other parts
of the process (separation plant, segment production works etc), which is normally only
available in analog form as shift or daily protocols. In order to consider these, they first
have to be processed and are only of limited use for the control of the drive due to the time
delay. Table 4-1 shows a typical example of the recorded data.

Table 4-1 Overview of the measurement data recorded during a shield drive.

Machine data
Progress Face su pport Mucking Grouting Operational state

- advance rate
- penetration
- overcut,
conicity
- jack forces
- revolutions,
torque and
direction of
the cutting
wheel
- consumption
of motors

- air bubble pressure
and bentonite level
(Hydroshield)
- distribution of the
support pressure in the
excavation chamber and
at the cutting wheel
- density in the excava-
tion chamber
- pressure and flow in the
pipes of the conditio-
ning agent (EPB shield)

- pressure,
revolutions
and torque
of the screw
conveyor
(EPB shield)
- pressure, flow
and density
in the slurry
supply pipes
(Hydroshield)

- grouting
pressure
and
quantity
of grout

- temperature and
pressure in the
hydraulic circuits
- temperature and
pressure in the
cooling circuits

Surveying data Additional analog data

Surveying in tunnel Geodetic data

- actual position of the
machine
- theoretical position of
the machine
- rolling
- machine
inclination / tilt

- settlement measurements
on the surface and on
buildings
- extensometer, inclinometer
readings
- pressure cell and piezome-
ter readings
- internal monitoring
sections and deformation
measurements

- properties of the support medium
(density, filtrate water discharge and
liquid limit), (Hydroshield)
- properties of the conditioning agent
(EPB shield)
- composition and properties of the
annular gap grout
- damage to the lining
- installation position of the rings
- shift protocols

The purpose of systematic data logging must be to gather all data on a project centrally, or-
ganise it systematically and make it available to all project parties for further processing (data
and interface management). The formation of information and knowledge islands should be