Method of and Appliances for Constructing Subterraneous or Open Excavations for Tunnels, Canals, and the like.
Year: 1894

page_text: Date of Application, 28th June, 1894-Accepted, 28th July, 1894
Method of and Appliances for Constructing Subterraneous or Open
Excavations for Tunnels, Canals, and the like.
I, PETER KRAUS, of 19 Hermannstrasse 10, Vienna, Austria, Engineer, do
hereby declare the nature of this invention, and in what manner the same is to be
performed to be particularly described and ascertained in aud by the following
statement:-
In the construction of excavations for tunnels, subterranean and open cuttings,
canals, and the like as at present carried out, comparatively large surfaces are from
time to time laid bare in the excavations without at once receiving proper support
from struts, framework &c., resulting frequently in the loosening of the soil
above or behind such surfaces, on account of the back pressure to which they
are subjected, in particular when excavating in sandy or loose soils; and by such
loosening, the strutting or framing which is afterwards introduced to support
such surfaces is often subject to very great pressures having a very detrimental
effect on their stability.
According to the present invention any such detrimental loosening of the soil in
excavations is prevented by an arrangement of strutting framing or scaffolding
so arranged that only a small amount of surface is laid bare without support
at one time whether during the operation of excavating, or during the subsequent
lining with brickwork or masonry, the said surfaces, after excavation or lining
being at once adequately supported again by strutting.
In consequence of this improved method of operating the requisite lining of the
excavation can be made considerably weaker than is at present necessary under
otherwise equal circumstances so that the requisite strength of resistance of the
lining structure will be obtained at a considerably reduced cost.
The above described method of supporting the sides of excavations so that only
small amounts of surface are left unsupported at any one time, is effected by a
travelling carriage with scaffolding or framework, running upon rails, which is
advanced at short intervals in proportion as short sections of the soil are
excavated.
The carriage running upon wheels employed for this purpose has mounted upon
it a supporting framing or scaffolding which is provided with rollers round its
periphery that bear against the separate lining battens or plates so as to keep
them pressed firmly against the surface of the excavation.
In order that the carriage frame may be adapted to work both in straight and
in curved excavations, it may be divided longitudinally into separate sections which
are either connected directly together when working on straight portions, or which
have intermediate pieces introduced on one. side, of a size corresponding with the
radius of the curved part on which it has to work. Or, instead of the above
arrangement, the requisite curved supporting surface may be obtained with a
straight rigid framing by arranging the supporting rollers on moveable supports
that can be adjusted outwards and inwards relatively to the scaffolding so as to
form the required curved surface. This adjustable arrangement of the rollers
would also allow of certain parts of the excavation to be made larger than
others, in order to give room for a thicker lining where needed.
The front upper portion of the framing is made to project in bracket form
beyond the lower portion, so that the upper rows of the supporting rollers are
of greater length than the lower ones, which enables the front of the working to be
excavated on an incline or in steps, the upper part being in advance of the lower.
part, such projecting upper part being stayed from the face of the lower part by

page_text: struts or brackets, and when the excavation of the front face is effected in an upper
and a lower stage, the upper part of the frame is provided with wheels running on
rails at the higher level.
At the rear end of the carriage, the bearers carrying the rows of the supporting
rollers overhang the framing, so as to enable a centering to be erected immediately
behind the carriage for building in the masonry lining.
The centering frames are connected together by longitudinal ties, which are in
line or nearly so with the longitudinal bearers of the moveable carriage so that the
front ends thereof may serve as abutments for the screw or hydraulic jacks for
effecting the forward motion of the carriage.
If necessary, the framing or scaffolding of the carriage may be made of two or
more different sizes, the front one being smaller than the back one so that by this
means a smaller excavation or driftway can be made in front and this be then
enlarged by the advance of the back part.
On the accompanying drawing is shewn by way of example a construction of the
above described excavating carriage, suitable for a tunnel for two sets of rails;
Fig. 1 shews a longitudinal section, Fig. 2 a cross section of the excavating
carriage the left hand side being the part at the face of the working while the
right hand side is the rear part.
Fig. 3 shews a cross section through the centering at the rear of the carriage.
Fig. 4 shews a cross section of a carriage suitable for the excavation in a cutting
to be subsequently arched over.
The carriage shewn in Figs. 1, 2 and 3 is for excavation in a straight line in
two stages. Each stage runs upon a separate set of rails, and is composed of
arched metal supporting ribs A A the lower ends of which are connected by
horizontal metal beams supported by twelve wheels arranged in rows, the axles
of which are carried in longitudinal bearers connecting the transverse beams.
The curved periphery of the ribs A which are suitably strengthened by transverse
and longitudinal stays as shown carry longitudinal bearers a, which connect the
several ribs together, there being 16 of such bearers on the rear portion, and 10 at
the front overhanging portion, and upon these bearers are carried the axes of the
supporting rollers b b, either directly or with the intervention of supporting
pieces cc, according as it may be required to excavate the sides to a greater
or less depth, or to excavate the sides in a straight line or in a
before described. In the latter case the supports cc' are made of such varying
heights as to cause the rollers to present the necessary curved outline. The
axes of each pair of rollers, which are square at their middle part as shewn,
are carried in bearings which are fixed either directly upon the longitudinal
bearers a or upon the supports c c¹, which are secured to the bearers a by means
by angle pieces b².
curve as
The longitudinal bearers a are extended backwards beyond the last rib A and
are supported by struts or brackets d, and the extensions are also provided
with rollers b as shewn, so that the centering frames can be erected immediately
behind the last rib of the carriage, and serve as abutment for the screws ; or
hydraulic cylinders carried by the carriage, whereby the periodical advance of
the latter is effected. The excavated surface is supported from the centering
frames by means of struts i. At the front end the upper longitudinal bearers
of the carriage are also extended beyond the front rib A and are supported
from the latter by struts or brackets d¹. On these extensions are also fitted
pairs of rollers bb three such pairs being on the uppermost three bearers, and two
pairs on the two following ones, the next ones having only one. The front ends
may advantageously be covered over by a cap or shield-like covering m which
prevents the soil from pressing directly upon the front lining battens until these
are properly supported by the front sets of rollers on the advance of the carriage.
When this is effected the space left above the battens by the shifting forward
of the cap m must be suitably filled in with rammed material in order to prevent
the sinking of the stratum above.

page_text: The object of the above described projecting arrangement of the bearers is to
enable the face of the working to be worked at a certain incline.
This face of the working is supported against subsidence by means of struts.n,
the front ends of which bear against the battens laid on the face of the working,
while the rear ends abut against screw spindles e screwing through bushes on the -
front rib A.
In proportion as the carriage advances, the screw spindles e are screwed back, so
as to maintain the support of the working face. When the spindles e are entirely
screwed back, the struts n are removed singly and after removing the corresponding
battens the soil is excavated in front to a certain depth, and the face of such
excavation is then again supported by the placing of a batten and strut and by
advancing the screw spindle so as to hold these securely. When the entire face
of the working has been advanced piece by piece in this manner and securely.
strutted, the advance of the carriage is again proceeded with, while turning back
the screws as described. A similar arrangement of screws e¹ and struts n' is
provided on the lower part of the framing for supporting the face of the lower'
stage of the working.
For maintaining the correct levels it is advantageous to provide on the front
frame of the carriage an adjustable plough-like device which in advancing is made
to level the bottom preparatory to laying down the sleepers for the rails.
In the construction shewn this device consists of an angle plate w having its
front edge sharpened and carried by an arm w¹ which can be adjusted vertically
upon the front frame of the carriage.
The excavation is effected, according to the greater or less cohesive nature of the
soil, to the extent of from 8 in. to 16 in. at each operation.
The lining battens f which have a corresponding width of from 8 in. to 16 in. are
then applied to the excavated surface and are immediately secured to the preceding
ring of lining battens, for which purpose fish plates f¹ Figs. 5 and 6 are bolted to
angle iron ribs f fixed to the back of each batten, at the two edges thereof, so
that the contiguous angle irons of two battens meet, as shewn at Figs. 2, 5, and 6.
The outer face of each batten is preferably made with a curvature corresponding
to the curved surface of the tunnel to be formed.
When the excavation requires to be made of an enlarged size at certain points
for affording room for stronger masonry, the increased size can be compensated for
by the introduction of filling pieces g g¹ of greater or less thickness between the
contiguous battens, as at Figs. 7 and 8.
After the battens have been secured as described, the carriage and frame is
advanced a distance corresponding to the excavated length, by means of the screws
or hydraulic jacks as above described, whereby the front rollers 6 are made to
support the freshly inserted lining battens.
As, when excavating in a curve, the outer side is longer than the inner side, the
longitudinal connections of the ribs A must be made adjustable in length in order
that each rib may assume the proper radial position to the curve, and the battens
employed on the outer side must be of corresponding greater width than those of
the inner side.
When the carriage has been advanced to an extent corresponding to the distance
between the centering frames L a new centering frame is introduced for the support
of the excavated surface left free by the rollers b on the rear extensions of the
bearers a, the radial struts i are then fixed in position with their inner ends bearing
against the curved surface of the centering frame, while the outer ends bear against
the lining battens. The struts may either be single, having cross pieces 12 bearing
against the battens, as at the right hand side of Fig. 3, or they may be in pairs
placed at an angle as on the left hand side, in which case they are tied together by
screws by tightening which their inclined ends are tightened up against the
inclined ends of the pieces 2 so as to force these against the battens which are
thereby pressed firmly against the surface.
When a portion of the excavation is enlarged to enable the masonry to be made
:

page_text: •
stronger at that part as shewn at the middle of Fig. 1, the front intermediate
pieces of such part must be removed and the corresponding rollers be replaced in
their normal position before an advance of the carriage can be effected.
When the advance has taken place, the intermediate blocks c' are introduced
below the rear rollers that have now entered the enlarged part of the excavation.
The longitudinal connecting pieces of the centering frames, are situated at
nearly the same level as the longitudinal bearers k of the carriage, so that the
screws attached to the latter may be in line with the former, which thus afford a
strong abutment.
In those positions where no longitudinal pieces can be provided facing the screws,
as on the horizontal member of the carriage frame, strong brackets / Fig. 1 are fixed
on this for affording the necessary abutment. According as the screws or hydraulic
jacks are all operated uniformly or more at one side or the other, the carriage frame
can be made to advance either in a straight line or more to one side or to the
other.
The centering frames are composed of an upper and a lower part between which
are arranged sand boxes of known construction.
When constructing a tunnel or excavation with an incline it will be necessary to
make end surfaces of the longitudinal bearers of the centering frames with a slope
corresponding to the incline. On this account it is advisable to make these bearers
of wood which can be readily cut to the desired shape and which can be made of
ample strength to resist the strains put upon them.
When a certain length of excavation has been completed, the building up of
the masonry lining is proceeded with, for which purpose certain portions of the
excavated surface, not in continuous connection are laid bare by the removal of the
struttings and the battens.
For excavating cuttings that are either to be subsequently arched over or left
open, the framing of the carriage is not made with an arched top, but with vertical
side uprights A Fig. 4, which carry the supporting rollers b.
Such a framing can be constructed in a single stage or in two or more stages.
The longitudinal bearers of the rollers are, as before, extended in the rear beyond
the last carriage frame A' while at the front they will project more toward the top
than at the bottom to correspond with the incline at which the face of the
excavation is worked.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
1. In the construction of subterranean or open excavations for tunnels, canals
and the like, the method for rapidly lining and supporting the surface of the
excavation wherein a carriage carrying the supporting frame or scaffolding is
advanced in proportion as the work of excavation proceeds, the frames A. or A'
of which carriage carry rollers that support the lining of battens placed against
the excavated surface the bearers supporting the rollers being made to overhang
the frames at each end in order, in front, to allow of the face of the excavation to
be worked at an incline and, at the back, to permit of a centering frame being
fixed immediately behind the carriage frame, as the carriage is advanced, the
excavated surface that is laid bare by the advance of the carriage being at once
supported by struts from the centering frames, substantially as described.
2. In the construction of excavations such as is referred to in the first claim,
the use of a moveable carriage running with wheels upon rails, and having
frames A on the periphery of which are mounted the axes b¹ of rollers bb that
run upon and support the battens forming the lining of the excavation, as the
carriage is advanced, the longitudinal bearers of the rollers being made to over-
hang the frames A both at the front and in the rear, substantially as and for the
purposes set forth.
3. In an excavating carriage such as is referred to in the second claim, the use

page_text: of screw or hydraulic jacks carried by the front frame A for supporting the face of
the working substantially as described.
4. In the construction of excavations such as is referred to in the first claim
the use of wood or sheet metal battens f for lining the excavated surface, provided
at the meeting edges of their inner sides with angle irons f³, to be connected by
fish plates, with or without the interposition of filling pieces g or g' substantially
as and for the purposes set forth.
5. In the construction of excavations such as is referred to in the first claim,
the use of centering frames L connected together by horizontal ties / the end
surfaces of which are presented to screw or hydraulic jacks carried by the rear
carriage frame, and serving to effect the periodical advance of the carriage,
substantially as described.
6. In combination with centering frames such as are referred to in the fifth claim,
the use of struts for supporting the excavated surface consisting of a pair of
struts i inclined to each other and bearing with inclined end surfaces against
inclines on cross pieces that rest against the lining battens so that by drawing
together the struts by means of a screw i¹ the transverse pieces are pressed
forcibly against the battens substantially as described.
Dated this 90th dow of Tun 1901
ABEL & IMRAY,
Agents for Applicant.