Subsidence Due To Coal Mining In The Harbours Of Ruhrort

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TECHNICAL TRANSLATION 1615
SUBSIDENCE DUE TO COAL MINING IN
THE HARBOURS OF RUHRORT
BY
H. BUMM
FROM
JAHRBUCH DER HAFENBAUTECHNISCHEN GESELLSCHAFT
30/31: 29 - 38. 1966/68
TRANSLATED BY
ROBERT SERRE
THIS
IS
THE
TWO
PREPARED
HUNDRED
FOR
THE
AND NINTH
DIVISION
OF
OF
OTTAWA
1972
THE
SERIES
BUILDING
OF
TRANSLATIONS
RESEARCH
PREFACE
Ground settlement due to underground activities such
as mining or the pumping of gas, oil or water is now encountered
throughout the world.
In many cases, especially in developed
areas, this settlement causes serious damage and creates
significant economic losses.
So far as is known within the
Division of Building Research, there is only one major case
in which settlement of the ground surface was deliberately
induced to assist in solving a serious problem at the surface.
This was the lowering by coal mining of most of the Harbour of
Duisburg-Ruhrort, on the Rhine, in order to compensate for the
reduced water levels in the river consequent upon its improvement for navigation during this century.
Dr. R. F. Legget,
former Director of the Division, was interested in this unusual
project and was able to visit the Harbour, by chance on the last
day of mining operations.
This paper was given to him by the
Harbour Director, Dipl.-Ing. Hermann Bumm, by whose permission
it is now included in this series.
The Division is grateful to Mr. Robert SerrA of the
Translations Section, National Research Council, for translating
this paper.
Ottawa
November 1972
N. B. Hutcheon
Director
NATIONAL RESEARCH COUNCIL OF CANADA
TECHNICAL TRANSLATION 1615
ri
t
Le :
Subsidence due to coal mining in the harbours
of Ruhrort
(Die Absenkung der Ruhrorter Hafen durch
Koh1eabbau)
Author:
H.
Reference:
Jahrbuch der Hafenbautechnischen Gese11schaft,
30/31: 29-38, 1966/68
Translator:
Robert Serre, Translations Section, National
Science Library
Bumm
SUBSIDENCE DUE TO COAL MINING IN THE
HARBOURS OF RUHRORT
There have been many technical publications dealing with
the subsidence of the harbours of Duisburg-Ruhrort as a result
of coal mining.
Since these particularly interesting operations
were completed in the summer of 1968, this paper will once more
summarize the process and consequences of subsidence, with
numerous references to previous publications on the subject(l).
1.
Erosion of the Rhine
The causes of Rhine erosion will only be described briefly.
The correction of the Lower Rhine during the last century involved the provision of a closed navigable waterway by linking
several islands.
The course of the Rhine was also shortened
by about 80 km through the elimination of major bends.
As a
result the force of the flow increased, causing more erosion.
This phenomenon was aggravated when the embankments were built
up, since the natural bank erosion changed to bottom erosion.
Navigation itself contributes to the drop in the river bed:
the propellers of the strong motorboats and tugboats stir up
the bottom.
Because of the heavy traffic, especially at low
water, the bottom is not at rest, and the stirred-up bed load
is continuously carried downstream.
work today.
This factor is still at
Since the turn of the century,
in the Duisburg area has dropped 2.40 m,
predicted by the year 2000
(Figure 1).
the bed of the Rhine
and a 1.60 m drop is
By then the slope of
the river bed at the mouth of the harbours will have decreased
to the point where excessive erosion will probably disappear.
However, it is too early to tell whether it will come to a
standstill.
_t
- 4 -
2.
Deepening the Harbours
It was necessary,
then, to plan and carry out radical
measures in order to maintain the depth of the navigable waterway in the harbours of Duisburg-Ruhrort.
This deepening of
harbour docks is not due, as in seaports, to the constant
increase in the size of ships, but is required simply to restore
water depth for ships of the same size and draught.
Until now, this subsidence of the Rhine bed has been overcome in the harbours by means of dredging after consolidating
the embankments(2).
So far, 15 of the 40 km of harbour shore-
line have been built up using the common construction method
for broken shorelines, i.e., an anchored sheet-pile wall in
the lower section and a stone-paved slope at the higher water
levels(3).
At present this costs about 3500-4500 DM per linear
meter.
Since further reconstruction of the 40 km shoreline would
have been quite expensive,
the planners considered the fact that
there are high-grade coal deposits under part of the harbour
docks, the extraction of which would provide some subsidence
of the harbour's bed.
Until then coal mining had not been
authorized for fear of damage to the harbour installations.
However, on the basis of the positive results obtained from coal
mining under the Rhine-Herne Canal(4) as well as under a quay
wall in the parallel harbour* in Duisburg, where damage to shore
installations was kept within reasonable bounds, it was considered that coal mining could be attempted under the harbour installations without serious danger.
There was also the fact that the water level in the lower
sill of the two entrance locks of the Rhine-Herne Canal, which
*
"Parallel harbour" denotes a harbour in which the navigable
waterway has been widened on one of the banks. (Transl.)
..
- 5 -
are in the immediate vicinity of the harbours, had dropped as
a result of the erosion of the Rhine.
Here too, the subsidence
of these two locks could restore the old water depth.
At the
same time the Westende Coal Mine, in whose concession the
"Sicherheitspfeiler"* was located, expressed interest in extracting the coal in this region, in view of its diminishing coal
supplies.
As a result,
there were discussions about discontinuing
the "Sicherheitspfeiler".
Thorough investigations revealed that
there were high-grade coal deposits
under the most important
part of the Ruhrort Harbour docks, and that it would be possible,
through their extraction, to lower the docks as well as the two
entrance locks by 1.60-2.20 m,
effects of erosion.
thereby partly offsetting the
In fact the docks and locks, which had in
effect risen in respect of the Rhine bed (Figure 2), would once
again drop towards the former water levels of the Rhine.
In 1951 an agreement was reached by the three parties,
the Hamborner Bergbau AG,
the Navigable Waterways Authority of
MUnster and the Duisburg-Ruhrorter Hafen AG, whereby the Westende
Coal Mine would extract the coal according to a definite plan,
while the Navigable Waterways Authority of MUnster and the DuisburgRuhrorter Hafen undertook to share the cost of mining damage
above a set level.
The mining company thereby assumed the
important and difficult task of extracting the coal with sufficient
care to provide clearly-defined subsidences and keep damage to
the many complex structures at a minimum.
The working of a mine
of such importance and involving these special security measures
had not so far been undertaken.
It was also a new and interesting
assignment for the Port Authority to maintain the harbours in
commission at all times during the mining subsidences, involving
the various structures, viz., 14 km of embankments, four coal
tips, 9.5 km of crane rails, 45 km of rail tracks, oil storage
tanks with a capacity of 300,000 m 3 and their pipe installations,
in addition to many buildings, always mindful to reconcile the
various interests of both the mining company and the Port Authority.
*
The "Sicherheitspfei1er" consists of zones where coal may
not be extracted because subsidences cannot be allowed to
develop. (Transl.)
-
3.
6 -
Coal Extraction Under the Harbours
Allowing for the possibilities and requirements above and
below ground, the six harbour docks of Ruhrort - A, Band C
as well as the Kaiser, North and South harbours - were to be
lowered by 1.60-2.00 m,
derne Canal by 2.25 m,
at a depth of 90-500 m.
and the two entrance locks of the Rhinethrough the mining of three coal seams
The mining company undertook to carry
out the subsidences shown in Figure 3, with a margin of ±5%.
The various figures are the result of mining operations.
Lowering the harbour area so as to compensate fully for
the 4.00 m erosion of the Rhine would have caused too extensive
a subsidence, thereby flooding some of the transport and loading
areas even at periods of slight high water.
The subsidences
which were agreed to are sufficient for the water depth of the
harbours and do not substantially affect high-water access to
the area.
The remaining difference in level could be compen-
sated by sheet-pile walls of lighter construction and reduced
dredging.
In the harbour area which stretches towards the Rhine
and in the Duisburg Harbour area, coal mining was not advocated
for financial reasons on account of the location and quality of
the coal deposits, of many faults,
and so on.
Consequently,
the traditional method of embankment consolidation and dredging
operations would have to be used there.
Since the locations of the coal deposits as well as the extent of the development operations involved in extracting the
coal have been thoroughly described in Hansa 1966, No. 17
(the publication of the Hafenbautechnischen Gesellschaft), we
will dispense with further particulars here.
4.
Mining Processes during Coal Extraction
The mining of coal deposits results in a subsidence trough
on the surface over the centre of the zone from which the coal
has been removed
(Figure 4).
Tensile stress occurs at the edges
-------'--------------~-~.~
- 7
of the area so disturbed because the latter's length increases
t
while compressive stress builds up directly above the zone from
which coal is removed.
The tensile stresses cause cracks in
buildings, breaks in conduits and cables and the separation
of rail joints.
The compressive stresses are more of a nuisance,
for they can cause more extensive damage to buildings as well
as the deformation of rails
t
conduits and pipe installations.
The coal was extracted from three seams in succession.
Coal-mining operations extended over the largest area possible
in order to achieve relatively even subsidences.
The areas of
extraction were about 200 m wide and extended in both directions
from a point of collaring (Figure 5).
For technical reasons
each coal face had to be a certain distance ahead of its neighbour.
Extraction at the various coal faces had to proceed at an even
pace in order to reduce as much as possible the occurrence of
additional stresses on buildings.
Such co-ordination of mining
operations certainly complicated things for the mining company.
But this requirement had to be assumed for the safety of the
surface installations.
The zones from which coal had been
removed were then partly packed with rock material
t
whereas
other seams are mined using the so-called caving method, whereby
the cavities are allowed to collapse completely.
method
t
With the caving
subsidences would be between 80 and 90 cm t with packing
about 50-60 cm.
If everything is running smoothly and no faults
are encountered, the mining of a face 200 m wide can proceed
at about 2-3 m per day.
When operations were at their peak
subsidences rose to about 1 cm per day.
subsidences reached 2 cm/day.
t
In one particular case
Surface subsidences were undulatory
and corresponded to the progress of the mining operations, thereby altering the gradient of railway tracks and pipe installations.
The choice of the first point of collaring was of special
significance for the surface installations.
stresses build up over its centre
Since compressive
(Figure 4), the point of
collaring is chosen where disturbances will cause minimum damage,
e.g., under the centre of a dock.
The coal face is preceded
by the zone of the tensile stress, followed by the compressive
stress over the middle of the extraction area, i.e., tensile
t'
- 8 -
stresses are partly neutralized by the subsequent compressive
stresses.
In 1954 the first point of collaring was set about
100 m west of Entrance Lock I in the outport of the Rhine-Herne
Canal (Figure 5).
As extraction proceeded towards it, Lock I
found itself in the zone of tensile stresses.
Since the expansion
joints of the lock chamber were only 1-2 cm wide, they could
not bear heavy compressive stresses.
As expected, the tensile
stresses loosened the expansion joints.
As the mining operations
proceeded under the lock, the compressive stresses were finally
brought into play and the expansion joints partly tightened once
again.
It must be added, however, that this process can only be
represented in simplified form, since subsidence involves other
forces, e.g., the earth pressure behind the lock chamber whereby
the lock walls tend to slant forward.
There are also torsional
forces, which exert some strain on the mining operations, but
they do not constitute a threat to stability.
In the spring of 1957 the first anticipated subsidence of
45 cm was achieved at the lower gates of Lock I.
At this time,
however, the upper gates of the lock had only subsided 9 cm,
i.e., the lock had assumed an incline of 36 cm on its longitudinal
axis.
However, the slope of the 180 cm lock was only 1:500,
and no operational difficulties were encountered.
The agreement
reached in 1951, stipulating that by 1958 Lock I should have
subsided 50 cm, is an indication of the precision with which
the mining company conducted its operations, for in the spring
of 1957 Lock I had subsided 48 cm.
In subsequent operations
the mining company reached its subsidence predictions with similar
precision.
Tae successful subsidence of Lock I was followed by subsidences
at docks A, Band C.
In the 12 years since 1957 subsidences of
1.50 to 2.00 m have been recorded, providing good navigational
advantages, as foreseen.
A fault zone has caused special difficulties.
It stretches across the docks, and faulting of the seams occurs
over short distances down to a depth of 200 m.
Tae extraction
of coal from the disturbed zone was at first delayed
(Figure 6).
As a result, an irregular subsidence developed over the harbour
area, having the appearance of a raised ridge.
Since then, however,
9 -
this has been compensated by mining operations in this zone.
Extraction is especially difficult in a disturbed zone, seeing
that special underground safety measures have to be taken because
of the pronounced inclines of the seams.
5.
Damage Caused by Mining Operations
Generally speaking, it can be said that mining damage does
arise, but that it need not necessarily happen.
In the light
of the foregoing a conclusion could be drawn that some damage
would occur.
Damage does not take place in a uniform manner,
but in places, since the structures are elastic and give up
to a critical point, and are then subject to breakage and so on.
However, the extent of the damage can be kept at a minimum if
steps are taken in ample time.
Thus, preventive measures were
taken, as far as was technically possible and justified, to
protect the installations, e.g., reinforcements, auxiliary
constructions, installation of joints, expanders, etc.
Heavy constructions respond best to subsidences.
Thus,
tne coal-mixing plant, which consists basically of a reinforced
concrete bunker 112 m long and 20 m high with 32 bunker pockets
of 240 tons each, responded to a subsidence of 1.80 m witnout
undergoing operational difficulties or cracking.
Lighter struc-
tures such as half-brick boundary walls, light temporary buildings
and so on usually suffer heavier damage.
Thus,
the light supports
of the loading bands of the coal-mixing plant became lopsided
and they continued to slope as mining operations progressed, but
by correcting the fulcrum supports it was not difficult to
straighten the steel construction and to avoid operational interruptions
(Figure 7).
As had already been observed on the Rhine-Herne Canal, the
sheet piling followed the subsidences very satisfactorily,
although the sheet piles involved were of greater length, and
the banks, which were all anchored, were subjected to greater
stresses.
As a safety measure a light crossbeam with short
joint spacings was used,
the better to follow the movements.
.t
-10 -
In some places the tensile stresses caused many additional
stresses in the sheet piles; in some cases
tations and previous experience
a short distance
(Figure 8).
t
t
contrary to expec-
the sheet piles cracked over
However
t
this damage was quite
easily overcome by using welded fishplates.
The wavelike movement
t
which the embankment as well as all
structures must undergo as mining operations progress
in Figure 9.
slightly.
is shown
t
Thus, the structures usually tipped and twisted
A sheet-pile wall 650 m long was built on the north
embankment of Dock C when mining operations had begun
end had already subsided 80 em.
driven with a slope of 80 cm t
and one
t
The top edge of the wall was
so that today it is almost norizontal,
now that mining operations have ceased.
Here
t
as elsewhere
t
it
was shown that the mine survey data concerning the anticipated
degree of subsidence were very precise.
Crane tracks may be regarded as among the most vulnerable
of the harbour's installations.
Any important change which takes
place has an unfavourable repercussion on the cranes and tile
loading bridges
play only.
t
in which the hanging supports allow for a little
The crane tracks must be kept rigorously straight.
On account of the flatness of their foundations,
easily to any soil movements.
they react very
The tracks on the water side and
on the land side do not always alter their position in parallel
fashion;
the position, level and slope of the two rails may
vary, so that a very close watch for such happenings must be
maintained by continual recourse to measuring.
Occasionally,
the undercarriage of the cranes had to be altered to make them
more elastic.
Figure 10 clearly shows to what extent shifting
may affect crane platforms of reinforced concrete.
In this case
the preventive measure consisted of builJing an intermediate
structure of I-beams so as to allow movement between the reinforced concrete slab and the supports.
This construction proved
useful, since otherwise the reinforced concrete supports would
have sheared off.
The effects of mining operations on the tracks were particularly noticeable.
The rails compressed and stretched
t
shifting
.t
- 11
their position on the ballast bed,
gradient was altered.
formed depressions, and their
This was especially noticeable in the case
of humps and dumper tracks, where wagons make use of the natural
slope.
Service conditions were altered in many places, and could
only be overcome by additional shunting personnel, e.g.,
men.
track-
If the rails were not adjusted or regulated in due time,
distortions occured (Figure 11).
The many switches,
turntables
and weigh bridges had also to be kept constantly stress-free
and operating.
A loop service duct was subjected to particularly
strong distortions, for it was not possible to adjust it beforehand
(Figure 12).
Particularly extensive precautions had to be taken with
the storage tank installations.
In one fuel depot alone on Dock A
there were 109 tanks with a capacity of 212,000 m 3, extensive
filling installations for ship, rail and road transport,
a network of pipe conduits extending some 60 km.
and
As many preventive
measures as possible were taken, especially in the form of
expanders.
In addition, it was found necessary to organize a
very close supervision by a smail team of mechanics for
the
efficient maintenance of the highly complicated systems of conduits
for oil, water,
cables.
fire-fighting equipment,
telephone and control
As a result of changes in length due to tensile and
compressive stresses, it was necessary,
expanders,
in spite of the use of
to alter the conduits from time to time.
The most expensive preventive measures had to be taken witn
respect to a bridge built for a city freeway.
the Berlin Bridge
long.
It was called
("Berliner Brlicke") and was more than 1800 m
The cost was shared between the mining company and the
bridge construction authority of the city of Duisburg.
Tue
reinforced concrete box-beam structure required additional reinforcement,
and the supports had to be installed in such a way
that they could be regulated at will,
subsidences.
to compensate the various
The bearings for the readjustment presses were
located at the foot of the supports
(Figure 13).
Upon completion
of the mining operations the concrete work will be removed.
The
greatest subsidences are as high as 2.00 m, whereby the bridge's
superelevated gradients were largely flattened upon completion of
- 12 -
the mining operations.
During the subsidence period the bridge
was measured in detail once a month from the roof of a high-rise
building 1 km away which was not affected by the subsidences
and from which the entire bridge could be well observed (Figure 14).
It was usually necessary to reset a whole series of piers together;
l~ hours were needed
for each pier.
The subsidence and alignment
of the bridge took place without traffic interruption.
The bridge
withstood the subsidence without any damage.
As soon as the first subsidences began, it was obvious that
a constant and very careful supervision of the harbour installations
would be required.
Meetings have therefore been held eacn Thurs-
day for years - some 400 to date - making it possible to take
necessary decisions at short notice and to avoid major damage
to structures as well as breakdowns in operations.
Each meeting
is attended by 10 to 16 representatives of the mining company,
the Federal Railway, and the harbour construction and operations
uni t
.
The prearranged agenda is followed by a discussion of
any questions concerning mining operations.
6.
So far,
Completion of the Subsidence Project
the coal in the area of docks A, Band C has been
extracted and the planned subsidences achieved.
Following the
agreement there still remained the Ruhr Lock and the Ruhr Dam,
as well as parts of the North and South Harbour to be lowered.
However, closer underground developments have revealed that the
fault extending through the harbour underneath the Ruhr Lock
and at the rear end of the North Harbour is causing such strong
disturbances that national mining authorities have forbidden
further extraction.
As a result, the subsidence of these areas
as provided for in the agreement is no longer possible.
Likewise
the subsidence target anticipated for the South Harbour and parts
of the North Harbour will not be reached.
The harbour authorities
will have to lower these harbour areas using traditional methods.
Taking into consideration the final subsidence levels,
two sections
of the embankment in these harbour docks and another in the harbour
canal, which is located in the drainage area of the Ruhr Lock,
..
--------'----------------~
- :i.3
have been provided with lighter sheet-pile walls
in recent years.
(profile II)
The depth of driving has been determined from
the anticipated subsidences.
Since these walls will in future
no longer suffice, they will have to be deepened or new sneetpile walls predriven.
However,
these can presumably be connected
to the old anchorage.
These are the only measures which Were
taken as a result of incorrect assumptions in this extensive
and risky project.
In view of the geological conditions,
could not be foreseen
7.
they
(Figure 15).
The Actual State of the Subsidence
A comparison of Figure 3, the estimated subsidence, with
Figure 15, the actual state of the subsidence, may give the
impresslon that the end result is quite different from what was
originally planned.
however, the extraction target was fully
reached in docks A, Band C, and even partly exceeded.
In fact,
tue final subsidences in the rear section of docks A and B is
2.00 m instead of 1.80 m,
as was originally planned.
A comparison
of Figures 3, 6 and 15 clearly shows that the ridge which had
first remained has now largely disappeared.
Between Dock Band
the Kaiser Harbour the final level of subsidence has not been
reached, but this is not important because this peninsula will
soon have to be reconstructed for other reasons, and the Kaiser
Harbour will be largely filled in to provide new leasehold property.
Only in the middle of the North Harbour do unfavourable conditions
remain, because there the subsidence lines are pressed very
strongly together as a result of the impossibility of mining
the upper North Harbour.
Consequently, there is a slope of 1.00 m
over a short stretch of this shoreline
(Figure 16).
The mining
company had to carry out and finance the extensive straightening
operations on the crane tracks, whereas the harbour authorities
are responsible for the additional work on the embankments.
Furthermore, coal extraction will be discontinued in the
peripheral areas, for technical reasons.
As a result the sub-
sidences, which so far have been quite flat on the edge of the
mining area, are now strongly concentrated, but this does not
- :..4
affect the subsidence of the harbour area.
Thus the mining operations under the harbours ended in the
summer of 1968, four years earlier than was planned in the agreement.
The Westende Mine had to stop its operations because its
coal supplies ran out.
The agreement enabled it to keep its
installations in operation an extra 16 years, for without it
the coal mine would have closed down in 1952.
The coal under the harbours was extracted with such a high
degree of skill that the operation was a complete success for
the Duisburg-Ruhrorter Hafen AG,
described above.
except for the few limitations
It should again be pointed out that the mine
surveyors performed exceptionally well, directing the mining
operations and predicting with great precision the subsidences
and their consequences, so that by taking preventive measures
it was possible to keep damage within reasonable limits.
It may seem incredible to an outsider that a complex structure
such as a harbour, with its extensive and varied installations,
could be lowered by 2.00 m,
the ground being actually cut from
under it, and yet the experience of many years and the skill
of the surveyors have proved that in spite of all assumptions
to the contrary it can be done.
Now that this uniquely interesting project has been completed,
all those who took part in it, working in close co-operation
and harmony and with a ready sense of responsibility, may look
upon their successful operations with great satisfaction.
References
1.
Bumm, H.
Die Vertiefung der Duisburg-Ruhrorter Hafen.
Bautechnik, (10): 1952.
- Bumm, H.
Die Erosion des Niederrheins und ihr
Einf1uss auf die Hafen. Hansa, (46/47): 1952.
- Bumm, H., Schweden, G. and Finke, G.
Die Absenkung
der Duisburg-Ruhrorter Hafen durch Koh1enabbau. Hansa,
(17): 1966.
2.
Schinkel and Grube
Sicherung von Pfei1erbauwerken in den
Duisburg-Ruhrorter Hafen. Bautechnik, p. 101 ff., 1937.
-
15-
3.
Finke~
40
Stall, Fo J.
Hlfen am Rhein-Herne-Kanal unter Einwirkung
des Bergbaues. Jahrbo BTG, po 356, 1962/63.
G.
Uferbau in Binnenhafeno
po 161 ffo, 1961.
Bauingenieur~
Der
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Fig. 1
Drop in the low water levels of
the Rhine from 1840 to 1967
Fig.
2
Old communication lock linking with
the Ruhr (built 1837-40).
At low water the sill is dry
N
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1tho
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Fig.
3
Estimated subsidence of the docks of Ruhrort Harbour
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Harbour of the Rhine-Preussen Coal Mine
Friedrich-Ebert Bridge
Railroad harbour
Rhine (river)
Ruhr (river)
Harbour canal
Harbour estuary
Vincke canal
Oberblirgermeister-Lehr Bridge
North Harbour
South Harbour
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
Kaiser Harbour
Docks A, B, C
Ruhr Lock
Spillway dam
Inner harbour
Schwanen Gate
Berliner Bridge
Lock I
Limit of rented area
North-South road
Rhine-Herne Canal
l7 -
Trogm#fe 7
,.
~fes IJOz'---....
8
Fig. 4
Phenomena arising in the course of
coal extraction when the seams are horizontal
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Zone under tensile stress
Limit angle
Original lay of soil on surface
Zone under compressive stress
Lay of soil after extraction
Subsidence trough
Middle of trough
Worked-out seam
Subsidence curve
Angle of break
-
/
18 -
/
I
I
.----1
I
-"'.£:..-=-----
L
Fig. 5
Coal extraction under lock I
1.
2.
3.
4.
5.
6.
Dock C
First eastern division, section 3.S
Sonnenschein seam
Influenced area, lock I
Limit of the marl
Gallery leading to the seams
~
.
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.1kJ
WES1 l',NV1'.
m
1~J~/
.
\~':
V;.
I
l
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I.C
I
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Fig.
I
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I
6
State of the subsidence in 1967
Legend: same as in Figure 3
Ii
.'
....,;:&"
_
20
Fig.
········~_····~~~~~ __ .~A~
~~
~
7
Subsidence of the supports of the cable installation;
the foundation has been widened for
the alignment of the support
Fig. 8
Cracked sheet piling
N
I-'
I:
:.,.,.,.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:. :. :. :. :. :. :. :. :. :. : . : . : . - . : .;.;.;.- . - .~.; .; .; .; . - .; .; · : · ; · _ ·. ·. ·u. y. v. ". · . ·: ·
••·_·~':-•• -_:-~-:
_
,,' ,=7''''''''''''''''_''''''''''''''","''''''''''''~h~'>~'''~'''
"
'';~'=~'='''=''''''''''''======='='h>'''''''''''=''===''
-
22 -
i',
: ~.
Fig. 10
Distortion of a crane platform,
with precautionary sl:l..deway
Fig, 11
Distortion of rails
Fig. 12
Distortion of a loop service
duct above ground
Fig. 13
Supports of the Berliner Bridge
2,O~
III
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.-
.',,-
~
(,0
11
I
,
I
,
4.
~
I
_
-J-
:
o
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, I I I I I "
I
;m'29 27 Z5 2J 2fXK18
Z942f1:2GiYI.22ZfJ
1
2
3
•
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45
I
f7
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.
-t
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_ Gradient
. aft er comp1 . of mlnlng
. 0 er at t.ons (shown as a straight:
ITne)-".,_.L_L~"""'>"'--"I-~'-~~.,.----r-_.
__._._--'. .
16 zr 14 : t3XJI 1f 10 9 l'JJF 7 e Y
4
3 III ---,. Pd I La r
..
.
:
,
: .'
•
:
: 13800 m 13600
13400
13200
~ bi,herige Ser!lvngf/1 his November 1960
4 _
I11III tisbc';c SmkurJc, va, J/lni 1,961 hi' OM 1961 5
1!iffIif bishenge Senleungetl '00 Juni 1%4 his Juf 19fjfi
:
.
.. .....
13000
12600
13600
12400
13300· 12000
11600
11600
bishenge Senkungen von Hill< 196iJ his Mdrz 1961 6 "-,,, bisherige Senlevngen von Mdrz 1961 bis Juni 1961
/}f'!lcriy Sen(u:qf" I'n' olt. 1961 his MarL 11M 7
bishmge Smkungen "" Marz'1964 /;is Juni 1964
Fig.
14
Subsidence of the Berliner Bridge
Subsidence
Subsidence
Subsidence
4. Subsidence
5. Subsidence
6. Subsidence
7 • Subsidence
12.
3.
!,-"
-I:'-
to Nov. 1960
from June to Oct. 1961
from June 1964 to July 1966
from Nov. 1960 to March 1961
from Oct. 1961 to March 1964
from March to June 1961
from March to June 1964
•
--_ ... _-\'
:
I
1
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+
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o
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.......J
m
noc
WESTE;"; IlE
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Fig.
15
Levels of subsidence reached in
the harbour of Duisburg-Ruhrort
Legend: same as in Figure 3
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..