Analogous Operations.
Year: 1886

page_text: Analogous Operations.
I FRIEDRICH HERMANN POETSCH, of Magdeburg, Sudenburg in the Empire
of Germany, do hereby declare the nature of my said invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
The object of my invention is to provide temporary tubbing for sustaining the
pressure of the earth, aqueous or other strata, or water, while excavating for and
erecting sinking or constructing mines, bridges, tunnels, and analogous operations.
And in order that my said invention may be particularly described and ascer-
tained, reference is hereby made to the accompanying drawings, in which similar
letters of reference indicate corresponding parts.
After measuring and indicating the dimensions of the object to be constructed
(such as a circular bridge pier) I sink a number of pipes or.tubes into the ground
or water bed, surrounding the object to be formed, and deeper than it is intended
to be built and at any suitable distance from each other, either vertically or
inclining, according to the pressure which is expected to ensue; as shewn by Figs. 1
and 2 I then fit upon such tubes wooden or metal plates b and b¹ provided
at each end with cylinders or sleeves c c¹ which slide upon and enclose the tubes,
and which in so sliding upon the tubes are pressed downwards by any suitable
means. Two methods of forming these plates are shewn in Figs. 4 and 5, which
will be understood from the drawings. When the sinking of the tubes a and the
pressing downwards of the plates b and sleeves c, is accomplished, surrounding the
site of the operations, another tube d. is sunk in the centre of the existing space of
any suitable section, and to such a depth as the excavation is required to be made.
This tube d is provided with perforations or other openings, or that the ground or
strata surrounding the tube d may enter the same and be raised by pumping
or other ordinary means, This removal of material causes the surrounding strata
to exert a certain amount of pressure outside the circle upon the plates 6 b¹ and
presses the same together as shewn in Figs. 3 and 6.

page_text: The upper ends of the pipes a a are supported by means of one or more fixed
rings e e or by any other suitable arrangement.
If all the plates b are pressed against the tubes a (as shewn in Fig. 3) the strata
outside is prevented from entering the enclosed space after the removal of the
material. When such removal has been effected water usually takes it place,
which enters either from below, or from the sides of the enclosure.
In order to prevent such water from entering through the sides cold currents
may be fixed into the tubes as described in my Specification filed on the 29th May
1883, N° 2,655 and by such means a frozen wall can be formed, which prevents any
further entry of water; or hydraulic cement may be used to fill in the openings
between the plates 61-In order to prevent the water from entering at the bottom
a layer of cement, bèton, or any other suitable material may be formed, and the
water which has already entered may be removed by pumping or in any other
suitable manner, after which the masonry may be laid, or other works proceeded
with, without any further hindrance.
When the works is completed the frozen wall is again permitted to liquefy and
the tubes a and plates b c are removed.
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. The method of forming coffer-dams, and rendering the same watertight by
means of sinking tubes a around the space to be occupied by the proposed
building, and by fitting, to such tubes plates of metal or any other suitable
material bb to such tubes, and which plates are pressed together as soon as the
inner material or strata is removed, all operating substantially as hereinbefore
described, and shewn on the drawings.
2. The method of filling and stopping the openings between the plates forming
the coffer-dam, by means of cement, or order to prevent the entry of water or
aqueous material, and in order to increase the resisting power of the plates, and the
strength of the coffer dam, substantially as herein before described and shewn on
the drawings.
3. The general construction, combination and arrangement of the several and
respective parts, or some of them, together forming my improvements in means and
appliances for the formation of temporary tubbing, to facilitate the excavation
for and construction of mines, bridges, tunnels, and other analogous operations,
substantially as hereinbefore described and shewn on the drawings.
1000
GEO. DOWNING,
Agent for Applicant.