Improvements in Sinking or Forming Shafts and the like in or through Aqueous Strata.
Year: 1890

page_text: Date of Application, 1st Apr., 1890
Complete Specification Left, 1st Jan., 1891-Accepted, 7th Mar., 1891
PROVISIONAL SPECIFICATION.
Improvements in Sinking or Forming Shafts and the like in or
through Aqueous Strata.
I, FRIEDRICH HERMANN POETSCH, of Magdeburg, in the Empire of Germany,
Civil Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to improvements in sinking or forming shafts or the like in
or through aqueous strata and has for its object to effect the work in a more
economical and speedy manner than hitherto.
In case the upper water, which runs down behind the metal tubing should prevent
the laying of the foundation of the tubings of the shaft I proceed in the following
manner :-
Either the bottom of the shaft is closed by means of cement, beton or the like
in bags or a helicoidal shaped freezing pipe is sunk in the water within the shaft
and cold air or a refrigerating liquid is supplied to the said pipe by a vertical
tube.
The air or liquid after having passed through the helicoidal tube is drawn away
through an exit tube. By this means a block of ice is formed at the bottom of the
shaft which will be the stronger the longer cold fluid is applied.
When a shaft is sunk according to the "Chaudron system and the flow of
water from above cannot be stopped by means of a "moss-box" an ice block is
formed within the moss-box and may be even extended over the said moss-box if
necessary.
The water within the iron tubing is drawn out and upon the bottom of mortar or
upon the ice block I construct a wooden support and reservoirs of air, of wood or
other bad conductor of heat in order to obtain an isolated space between them, and
the iron tubing of the shaft.
When the frozen wall is strong enough (which can be ascertained by boring
horizontal holes from within the shaft towards the outside) it will be easy to
descend through the free space to the bottom of the shaft, where the aforesaid
wooden support is opened and the mortar or ice underneath is removed, and if
required the shaft is sunk a further section deeper until it meets a firm strata,
where it is enlarged to invest it with the wedging crib, which is fixed and wedged
and the whole shaft is then "timbered" with iron rings or otherwise from the
wedging-crib up to the top of the shaft; the "moss-box" is removed and the lower
Behind the
iron rings are hermetically joined to the upper tubing of the shaft.
iron rings and above the wedging crib a space of say.1 meter in height is filled with
dry loose cement. The space up to the first iron-tubing is filled behind with dry
beton or cement.
Then the reservoir as well as the pipes and the supports are removed and the
shaft is filled with water say to 1 meter above the frozen wall and then with water
of say+40° Celsius.
This water is maintained at a temperature not below +30° Celsius during and
say a month afterwards it is drawn out from the shaft, in order to continue the
sinking in the ordinary way.
The aforesaid freezing process is employed when aqueous strata are met.

page_text: COMPLETE SPECIFICATION.
Improvements in Sinking or Forming Shafts and the like in or
through Aqueous Strata.
I, FRIEDRICH HERMANN POETSCH, of Magdeburg, in the Empire of Germany,
Civil 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 and by
the following statement :-
My invention relates to improvements in sinking or forming shafts and other like
excavations in water bearing soil or aqueous strata and consists essentially in
conducting the operations in the manner hereinafter described whereby the water is
enabled to be excluded in a more efficient manner than is possible with the means
heretofore employed.
And in order that my said invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed sheet of drawings the same letters of reference indicating
corresponding parts in all the figures.
Figure I of the accompanying drawings illustrates in vertical section the means
employed for excluding the water in the operation of sinking a shaft in water
bearing soil.
Fig. I represents a horizontal section taken along the line 1-2 Figure 1.
Figure I represents a similar section taken along the line 3-4 Figure I.
In carrying out this invention when employed for excluding the water from a
vertical shaft or well such as that illustrated in the drawing the shaft is sunk by
hand through the dry upper strata and by means of any known mechanical process
through the aqueous strata until a solid water tight strata at 6 Figure I is attained
after which the entire shaft or its lower part only is timbered or lined with an iron
lining a the upper part being lined with masonry or battens according to the nature
of the strata.
The shutting off or exclusion of the upper water in a shaft of this description is
effected according to my invention in the manner next hereinafter described.
A single or multiple spiral or coiled freezing pipe e Figures I and III connected
to a vertical admission or supply pipe and to a vertical rising or discharge pipe g
is sunk or let down into the bottom of the shaft, the pipes and being lagged or
insulated from the water within the shaft by a covering of material which is a bad
conductor of heat.
Through the pipe fa refrigerating agent or liquid is supplied which circulates in
the coile and returns through the pipe to the refrigerator from whence it is
exhausted by a pump and again forced through the pipes g, e and f.
In consequence of the circulation of the refrigerating liquid through the pipes ge
and and by means of fine sand thrown into the shaft a solid mass of ice or frozen
material hik Figure I is formed after a certain time at the bottom of the shaft
which extends to and makes a water tight joint with the under part of the iron
tubbing or lining a of the shaft. After this has been done the water contained in
the shaft can be easily removed or pumped out and a wooden staging or support m
Figure I is then constructed on the bottom of the shaft.
On the said support or flooring m a cylinder n o p q of wood about 0.5 meter
smaller in diameter than the iron lining-a-and-of-suitable height corresponding to
--the-length of shaft operated on is erected being made air and water tight and
separated or insulated from the said lining. The upper end op of this cylinder or
air reservoir is closed by another air and water tight flooring after a vertical
serpentine piper connected to admission and discharge pipes and t has been
placed in the annular space of about 0-25 m. in width between the wood cylinder n
op q and the iron tubbing a the upper part of this space being closed by a projecting
part of the cover of the cylinder n o p q.
A powerful refrigerating agent such as a solution of chloride of magnesium is then

page_text: caused to circulate in the pipes srt in order to cool the annular space between the
outer iron tubbing a and the inner wooden cylinder n o p q until the cooling action
takes effect horizontally through the said iron tubbings on the surrounding soil or
strata.
The refrigerating liquid is caused to circulate in the pipes until the surrounding
strata is frozen to a sufficient thickness forming an ice wall A B C D.
The cold will not or only in a very slight degree pass through the insulating walls
of the cylinder n o p q..
The frozen mass or ice wall A B C D, formed outside of the iron tubbing or
lining a prevents the water from flowing down outside the said lining and penetrating
into the bottom of the shaft. By these means the water can be effectually kept out
of a shaft constructed according to the "Kind-Chaudron" system and in which the
upper water cannot be excluded with ordinary appliances.
After the ice wall A B C D has been formed as before described doors in the
air chamber or wood cylinder n o p q are opened at o p and q the frozen material
or ice in the space bhiklis removed and the under part b of the shaft is continued
into the firm or impervious strata the temperature being maintained at about-
3° Celsius; then the cribs are put in place and wedged and if necessary the moss
box or packing of moss employed in the Chaudron system and indicated at c in
Figure I is removed under the protection of the ice wall A B C D and the junction
between the cribs and the iron tubbing or lining a is made in the well known
manner. Before placing the fitting ring in position the space behind the junction
tubbings is filled up with dry loose pulverized cement of good quality.
After the junction or connection between the wedging cribs and the iron
tubbing has been completed the pipes s, e, t and s, r, t as well as the insulating
cylinder n o p q are removed from the shaft which is filled with hot water the latter
being maintained at a temperature of + 40° C. during about four weeks.
At that temperature the ice wall or frozen mass A B C D becomes thawed the
upper water behind the tubbings penetrates the dry and loose cement at the back
of the lowest tubbings and causes this cement to set or harden in about 4 weeks.
After this time the shaft is emptied and the sinking of the same may then be
proceeded with the water from the water bearing strata being effectually prevented
from penetrating to the interior of the shaft.
In order to exclude the water from an excavation for a bridge pier lined with
either iron masonry or wooden or frozen walls the pipes fey only are employed for
freezing and the bottom is frozen in the usual way. The water being pumped out
or removed from the shaft or excavation, a mixture of straw dry loose pulverized
cement and fragments of bricks is placed in the excavation so as to fill it up to
about 1 metre above the natural water level the frozen bottom bhi k is then thawed
by the circulation of a hot liquid such for example as a hot solution of chloride of
magnesium in the tubes fe and g which at the same time serve as a grating and
remain under the pier. The straw in the above mixture enables the water to
penetrate the mass of beton or concrete which is completely hardened in about
2 months.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
First. In sinking or forming shafts or like excavations in aqueous strata the
method of excluding water by freezing the bottom bhikl of the shaft, removing
the water from the shaft by means of pumps or otherwise, providing an annular
space insulated from the central part of the shaft for the reception of pipes for the
circulation of a refrigerating agent in order to produce a frozen wall A. B. C. D
outside the tubbings of the shaft, enlarging and sinking the shaft in order to insert
one or more wedging cribs in the solid strata under the protection of the frozen
wall A. B. C. D. filling the space behind this lower tubbing with dry loose powdered
cement which sets when the ice wall is thawed by the circulation of a heating

page_text: medium and connecting the under wedging rings with the upper tubbings under the
protection of the said wall A. B. C. D substantially as hereinbefore described with
reference to the accompanying drawings.
Second. The improved method of sinking or forming shafts in or through aqueous
strata substantially as herein before described.
Third. The improved method of sinking or forming excavations for bridge piers
or the like in or through aqueous strata substantially as hereinbefore described.
Dated this 1st day of January 1891
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, Agents..