MAINTENANCE OF TUNNELS WITH THE HELP OF SPATIAL
INFORMATION SYSTEMS
Prof. Gerd KEHNE, Germany
Key words: Maintenance, GIS, tunnel, traffic lines.
Abstract
This article presents the prototype of a 3-dimensional, modelled
spatial information system for underground transportation facilities.
With its help, it is possible to maintain and operate tunnels more
effectively.
Road or rail tunnel maintenance must be considered from the aspects
of securing value and safety. In many cases, it is based on analogous
sources of information - lists, files and plans - derived from
construction documents. This poses a problem for generally speaking,
the documents which originate during the planning and construction
phases are not geared to maintenance.
If one considers complex underground transportation facilities,
such as e.g. Underground rail systems, then an immense flood of
information is available. This relates to the tunnel and station
structures, the traffic installations, the ventilation, safety and
other features. Although these data initially stem from these
different areas, essentially they cannot be administered separately on
account of existing dependencies. The documents, realized and
administered separately, are in many cases not suitable for
integrative and structured presentation and targeted evaluation with
respect to the data required for maintenance and for modifications.
A prototype of an information system for underground transportation
facilities is to be presented here, which closes this gap and forms
the basis for improving the economy of maintenance and tunnel
operation. This system is founded on information systems, which have
made an impact on other specialized fields, for instance, on geo
information systems (GIS) or facility management systems.
1. INTRODUCTION
The first known tunnels were in Babylon and are dated from about
2180 until 60 BC. [IFGB] It can be assumed they were not documented
through an information system. In London the first underground started
in 1863. Berlin got its first underground in 1906. Both are still in
use.
In the last century railways were developed. For the narrow
guidelines of finding routes tunnels have always been an unavoidable
help. Today the speed of trains is increasing. This means engineers
show a stronger interest in building tunnels.
More tunnels have been built for streets also. This is to achieve a
higher speed for cars, for the increasing number or for breaking up
difficult traffic-situations.
Fig 1: Entrance of one tunnel of Frankfurt
Underground
It is tune of all tunnels that they are buildings of high value.
This is not only due to the high cost of erection but also to the
expensive equipment installed inside. To maintain the value a lot of
regular maintenance has to be carried out. And for this an-up to-date
actual documentation is necessary. Experience has shown that typically
the documentation is not up to modern technical standards for
maintaining tunnels as economically as possible. Today one still finds
conventional documentation in analogous files, lists, card files, or
single digital files, along with the well known problems with
combining and selecting the information.
2. MAINTENANCE OF TUNNELS
Tunnels are not just holes in the earth. They are cavities building
a three dimensional linear geometry and reaching the surface on each
side. They normally contain equipment for traffic.
Respecting to the high value of tunnels strategically planned
maintenance has to be realized.. In defined intervals inspections have
to be carried out. Especially when running nets of tunnels, e.g. at
underground networks the maintenance effects high costs.
In Germany the maintenance of tunnel buildings is ruled by DIN
1076. It distinguishes between:
| - main inspection every 6 years |
close examination - hand distance -
of all relevant parts like grounding, load capacity, sign
posting, construction elements, water seals, disguising,
corrosion, lines etc. To get the near the help of trestles is to
archive. |
| - medium inspection every 3 years |
detailed visible inspection of
relevant elements of the building like in the main inspection. |
| - simple inspection every year |
Walk through for getting notice
of visible irregularities. |
| - special inspections |
Main inspection after special
incidents like accidents, fire, earth quakes or break in of
water |
Tab. 1. Times of Inspection
As shown in Tab 1 the maintenance starts with a main inspection at
the time of the handing over of the building. In the following years
simple inspection take place. Every three Years a medium inspection
and after six years a main inspection is to be done. The second main
inspection takes place when warranty expires, it offers the last
chance to find and correct damages.
Fig 2: Situation of damage in a tunnel
Special inspections will only be made in case of special incidents.
After accidents of cars or of trains the tunnel itself and the
installed equipment may be damaged. So if need be an inspection is
necessary to see to the safety of the building. In case of fire, earth
quake or break in of water a special inspection is obligatory.
Additionally the maintenance of the installed traffic equipment is
to be carried out. This depends on rules for streets or rails, e.g.
the DS 853 of the German Rail DB AG.
The results of the inspections are a documentation discovered
damages. An example is shown in Fig. 2. They are classified in
categories such as
- urgent, immediately to be repaired
- not urgent, but to be repaired in medium term
- to be watched, to be repaired in long term.
The classification is of course a balance between the budget of
maintenance and safety.
The documentation is normally conventional. This means that plans,
analogous files list or digital files are supplemented. This leads to
the known problems with combining and selecting the information.
Seldom software solutions for documenting inspections are found.
In the field of maintenance of tunnels those categories of damages
are of interest, which are to be compared with future or past
situations. This comparison leads to measures for future repairing.
3. DEMANDS ON A CA-MAINTENANCE
The observation of points of damage has several aspects:
- how does the damage develop?
- where is an identical damage to be found?
- what do the points of damage have in common?
These aspects lead to the demand of an integrated data pool.
The comparison of change in situations during the time demands
descriptions in which the
- position
- appearance
- expected consequences
- possibly the cause
are named. These information should be completed by graphical data,
which could be pictures or drafts. The integration of the
alphanumerical and graphical data leads over to the chances a spatial
information system can give. Only these information systems, kinds of
GIS, guarantee a conclusion between positions and the information
belonging to objects.
The documentation of the damages in the appearances, the causes
etc. in an integrated data pool opens the chance to produce statistics
in an easy and simple way. These statistics give help in planning the
maintenance budget for a certain time and improve the procedure of
maintenance. So they are to be demanded.
An information system for the maintenance has to support the
description and the classification for discovered damages. This has to
result in the comparison with other damages for a better forecast of
estimated consequences.
Handling information is always embedded in the processes. Whenever
processes are running information on objects are needed for
manipulating. Maintenance is a process like many others. So it is to
be demanded, that the process of maintenance is projected into the
CA-system within the function model. This is valid for all processes
depending on data of the tunnel. The embedding is prerequisite for
reducing costs by better calculations and for optimising the
processes.
This nearly global task for a CA-System to maintain tunnels demands
that all themes relevant for technical descriptions have to be part of
the system. Considering this the maintenance for the building of the
tunnel itself and of all its equipment can be supported by the system.
This means that all elements are to be described in the data model.
For the use of the system it is to be demanded, that all users
taking part in running the tunnel have to be connected to the system.
So there is a need for a network that connects the users and for an
overlay so that the users can identify the specifics of their work
So the CA-System for maintenance is an information system for
subterranean traffic lines and the targets are:
- the graphical and alphanumeric technical description of the
tunnel buildings with information about the surrounding earth and
about the surface-buildings, as well as about to the geotechnical
control
- of the technical equipment for the traffic, supply, disposal and
safety
- in a necessary geometric accuracy
- with a grade of details being sufficient for the tasks in
projecting, erecting and operating the tunnel system.
Following this definition and the demands mentioned before an
information systems for supporting the maintenance of tunnels was
created.
4. SYSTEM STRUCTURE
The prototype of an information system for tunnel maintenance
corresponds to the structure displayed in Fig. 3. The core of the
system is formed by the objects, or rather their definition and the
object administration. Storage is executed within a data bank, which
forms the software basis in conjunction with the basic software of the
information system. With the aid of communication, which embraces both
of them, the exchange of data with external applications and to
internal methods and functions can be undertaken. The user gains
access to the system via the user surface.
The objects within tunnels are geometrically modelled
3-dimensionally for the system and stored in a data model together
with the attributive data definition. This definition is accomplished
within the scope of a system analysis. The objects concerned are
either 3-dimensional bodies, spatial curves or symbols. All objects
are or can be linked with alphanumerical data. This allows the user to
obtain both selective and combinative scanning of data, thematic
presentations as well as freely selectable projections, i.e.
isometrics, perspectives and sections. Fig. 4 contains a freely
selected section.
The record of geometries and alphanumerical data must take place in
accordance with the data model. In other words, a geometrical
3-dimensional data acquisition is predetermined. With the help of
classical geodetic methods with accompanying extraction of
alphanumerical relevant data, this is extremely complicated and both
cost and labour intensive. Other methods based on scanner techniques
for data acquisition and visualisation were developed. It has to be
found out to what extent, the objects presented in a data model and
their relevant data can be derived with the help of these methods.
With the aid of so-called secondary acquisition methods, i.e. through
conversion of analogue into digital components, it is also possible to
acquire the data. However, the aim has to be to introduce digital data
components, which originate during planning and construction. In the
prototype, the objects' geometries were obtained through parameterised
design.
Fig 3: Basic setup of system
The geometrical accuracy for the expansion and the placing of the
objects is also geared to the user's requirements. The following must
be taken into consideration in this connection: The expansion of the
region of presentation embraces the tunnel and the environments of
relevance to tunnel. Under certain circumstances, this field can
consist of wide areas of an urban zone, in which magnitudes in the
millimetre range are of significance. The geometric accuracy depends
on the degree of detail of the individual objects. In this way, a wide
range of co-ordinates ensues from overview to detail presentations. In
such a case, it is advisable to create special presentations if need
be. The presentation of convergences of the tunnel cross-section
resulting from geotechnical influences is realised as an example. It
is essential that the special graphics are derived from the general
data store, i.e. a logical linkage exists, which secures the integrity
of the data.
The application of a spatial information system for underground
transportation facilities especially for the maintenance relates to
the fields, which are to be referred to in the following sections. In
each case, suitable functionality for targeted application must be
catered for. In addition, an information system should be embedded in
the user's commercial proceedings. It cannot be accepted given the
anticipated investments for the information system that existing
operational procedures, the workflows, are not harmonised with the
benefits of the system. Conversion results in cost saving and more
effective utilisation of the system.
Fig 4: Tunnel cross-section
Ensuring that data are kept up-to-date demands organisational
embedding in a user's commercial activities. The system's
organisational allocation must be undertaken by the department, which
operates the tunnel and its facilities. However, it is imperative that
those departments, which are responsible for using and updating the
data, also have access to them. Principles relating to responsibility
and competence have to be adhered to in order to ensure that the data
are always up-to-date. Subsequently, the data are updated by the
department, which generates them. In other words, in the case of
maintenance, all determinants and measures have to be acquired by the
responsible department and fed to the information system through a
data flow that has to be devised.
5. SYSTEM USAGE
When having available a full three-dimensional data store, a wide
field of applications are possible. The prepared information system
documents the tunnel and its facilities. The degree of detail depends
on the tasks, which the information system is called on to perform. In
this way, it becomes the information source, which can comprehensively
supply all the data for the tasks - necessary for all jobs in the
tunnel. The results of all jobs must be acquired by the system so that
they are available for subsequent works.
An information system for the support of the maintenance of tunnels
has to fulfil the demands mentioned before. So it is to be embedded
into the process of maintenance. An example how this process can be
run under the control of the information system is shown in Fig 5.
First the functionality has to contain all regulations fixed in the
norms, for Germany the DIN 1076. Secondly the system is to be embedded
into the processes of the runner of the tunnel. This leads to an
automatic observation of the terms in which the different elements of
maintenance have to be executed. The system "knowing" in
which year which kind of inspection is to be done can be used to
extract the single works. This means the works can be planned over the
year and the necessary manpower can be calculated.
Fig 5: Course of a maintenance cycle
The result of the extraction is a dataset of the to be inspected
elements. This can be used to be completed by the results of the
inspections, the discovered damages and their classification. At best
this is done by using a handheld computer in sight of the objects. The
data led back to the system will help to analyse the cause, the
effects and the consequences. In the end the maintenance itself can be
proved and works, periods and strategy can be adjusted. The comparison
of damages in respect of other information will also support the
estimation of the causes and the effects. This can lead to a proving
of the future strategy in building tunnels.
The same applies to changes in the status. Plans for modifications
to a tunnel or its facilities require data pertaining to the existing
status, in the case of which both geometric and alphanumerical data
are of interest, which describe existing objects. The surrounding
ground is of interest in conjunction with a tunnel. It is determined
by exploratory bores and during the excavation. With these information
any changes in the tunnel can be projected.
Especially large underground stations have lot of areas. These have
to be administrated, because they are of considerable value. They are
e.g. used for:
- movement of passengers
- shops
- technical areas
- miscellaneous
Many areas can be let. It is important to have an overview on the
size and the surface of every area for administrating cost and income.
The safety from danger like fire is discussed very deeply today.
This means the fire protection should also be an aspect of the
information system. All data of installed elements dealing with
question of fire are to be saved as well as information to fire
fighting devices. With these fire protection concept can be proved and
continued after all changes in the tunnel. The system may give help
also in the case of fire. This means that a possibility has to be
created that fire fighters can inform themselves about the actual
situation in tunnels. This is important especially for underground
nets, which grow over a long time and where different building
techniques have been used or multiple uses of areas in underground
stations can be found.
6. CONCLUSION
In sum it is shown, that a spatial information system with its
capabilities is able to support many aspects of running a tunnel or a
tunnel system. These are the managing of areas in underground
stations, the support in documenting and continuing a fire protection
concept. as well as documenting the tunnels and the installed
equipment for showing the state and for delivering basic plans for the
projecting of changing the buildings.
Many efforts in running tunnels are spend in the maintenance.
Projecting the relevant rules and the necessary workflow as functions
into the system will help to optimise the process of maintenance.
Optimising normally leads to a reduction of costs. Like every
information system the described one facilitates to get knowledge
which one can only get on other ways with unacceptable effort. So it
helps to preserve the investment by an optimised budget.
REFERENCES
Bill, Ralf „Grundlagen der Geo-Informationssysteme", Band 1
und 2, Wichmann Verlag Karlsruhe 1999
IFGB: Unterirdisches Bauen, Unterlagen für Studium und Praxis,
Institut für Grundbau und Bodenmechanik, Technische Universität
Braunschweig, 1988
Kehne, Gerd „GIS-Usage for subterranean traffic lines", in
„Third Turkish German Joint Geodetic Days" Seite 295-302, ISBN
975-561-159-2, 1999
Spacetec Product information of Spacetec TS 360 , Spacetec GmbH,
Salzstraße 47, D-79098 Freiburg.
L. Wichter; u.a. Tunnelbau, Expert-Verlag Sindelfingen 1986
BIOGRAPHICAL NOTE
Gerd Kehne, born in 1958, study of Geodesy in Braunschweig
& Hannover in 1978-1984. 1989 doctorate (Dr.-Ing.) at the
Technical University of Braunschweig with a theses about collecting
data of existing buildings aiming to project an information systems
for buildings. 1989 - 1994 working at private offices on questions of
GIS.. Since 1994 Professor at the Fachhochschule Frankfurt am Main,
University of Applied Sciences for the subjects of Geo-Information.
Internet: http://www.fbg.fh-frankfurt.de/wir/kehnep/kehne.html
CONTACT
Prof. Dr.-Ing. Gerd Kehne
Fachbereich G
Fachhochschule Frankfurt am Main - University of Applied Sciences
Nibelungenplatz 1
D-60318 Frankfurt am Main
GERMANY
Tel. + 49 69 1533 2342
E-mail: kehne@fbg.fh-frankfurt.de
15 April 2001
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