US1894206A - Caisson work - Google Patents

Description

L. R. TALBOT Jan. 10, 1933.

CAISSON WORK Filed Oct. 11. 1930 INVENTOR man f?. Td/bat ATTORNEY M- H .mu m 91.9 uw

.La W Z Mn- M/ Patented Jan. 10, 1933 UNITED ,STATES PATENT olFFlcE LYMAN R. TALBOT, F PORT WASHINGTON, NEW YORK, ASSIGNOR TO CEMENT GUN COMPANY, A CORPORATION 'OF DELAWARE CAISSON WORK Application iled October 11, 1930. Serial No. 488,095.

rIhis invention relates to caisson work and more particularly to work of this kind in which the caisson is carried down by adding successive rings at the bottom as soon as space is provided therefor.

The aforesaid method of adding successive rings involves the formation of said rings in sections so that they can be lowered through the previously installed portion of the caisson andfthen assembled and secured to the lower end of said previously installed portion.

The use of caissons built up in this way obviates many of the difficulties previously encountered, but gives rise to other difficult problems including that of sealing the joints thoroughly and expeditiously to enable maintenance of the desired air pressure with compressor equipment of substantially the usual capacity.

Heretofore, attempts have been made t0 seal the joints in such caissons in different ways, but none of such attempts have been satisfactory. For example, where ordinary calking material has been forced into the 25,' joints the result has been rather to increase air leakage than to decrease it. It is also impracticable to seal the caisson by use of material requiring the use of forms.

An important object ofthe present inven- BU tion is to provide for overcoming such diiiiculties and preventing any substantial amount of air leakage. Further objects are to provide improved caisson structure and an improved method of sealing joints of sectional caissons to prevent leakage of air.

The objects of the invention may in general be attained by sealing the joints by the application thereto from a nozzle, as by the use of compressed air, of plastic material such as mortar hydrated either at the nozzle or before reaching the nozzle. Preferably the sealing of the joints is effected by applying Gunite by means of a cement gun.7

Other objects and advantages will be apparent upon Iconsideration of the following detailed description and of the drawing, in which:

Fig. 1 is a view, principally in vertical section through the axis, illustrating a preferred 501 embodiment of the invention as applied to a caisson with an air lock on the upper end thereof;

Fig. 2 is a transverse section of a caisson ring; and

F ig. 3 is a fragmentary section illustrating a modification.

Referring to the drawing, 10 designates a caisson extending downwardly through the ground 11 and built up of rings 12 comprising sections or segments 13. As here shown, there are four segments or quadrants to each ring and eachy of these segments is of plate material or the like with a maincportionof appropriate shape to form part of the outer wall of the caisson and with flanges 14 extending inwardly from the edges thereof to facilitate the attachment of segments together from the inside thereof to form rings and the attachment of successive rings together to form a caisson including more than one ring. Adjacent lianges may be secured together in any suitable manner as by means of bolts 15 passing through the flanges and secured in position by nuts 16.

With this form of caisson, there `is no necessity for driving or forcing the caisson down into the ground, but segments 13 for additional rings are lowered through the previously assembled upper part of the caisson and, as soon as sufcient material has been excavated at the lower end of the caisson and removed, another ring is assembled and secured to the ring which was previously the bottom ring. Although the caisson is illustrated as of circular cross section, the cross section may take other shapes.

In excavating at the lower end of the caisson use may be made of a shield 17 surrounding the caisson so as to be guided thereby. Preferably the peripheral wall of the shield 9 is provided with a suitable cutting bottom edge and to facilitate the sinking of the shield it is provided at its inner surface with a suitable peripheral shelf or ledge 18. By striking the ledge from above or exerting downward pressure thereon, as by means of' j acks, the shield may be driven downwardly as fast as the material is excavated. It will be seen that the part of the shield above the ledge is of sufficient height to enable the 100 flangel21 and spaced therefrom is a flange` assembly of a ring 12 above the ledge without disconnecting the shield from the bottom ring previously7 assembled and secured in position.

In general, caions of this nature are sunk below the water level which may be above, below or at the surface of the ground, and the Work must be carried on under air pressure which serves to prevent the water from entering in sufiicient volume to interfere with the work.

In order to maintain the necessary pressure while permitting the admission and withdrawal of men and material, the caisson is provided atits upper end with an air lock comprising a casing 19 provided at its bottom with an opening 20 surrounded by a flange 21 which, as brought out hereinafter, serves as a door frame. Surrounding the 22 forming part of a strip of angle iron securedto the bottom of the casing.

The flange 22 fits around the reduced upper end of a ring 23 of plate material of 26 which the lower end rests on the upper sectional ring 12fof the caissonfproper. The lower end of the ring 23 is provided with an inwardly extending flange 14 bolted to the anges 14 at the upper edges of the ring segment 13. Connecting the lower part of the reduced upper end of the ring 23 with the upper part of the lower end is a substantially flat annular portion 24 through which connections between the inside and outside of the caisson can conveniently be made.

The opening in the door frame or flange is closed by a door 25 mounted for movement in one direction to engage the lower edge of the flange 21 to close the opening 20, and in 40? another direction to open said opening 20.

As illustrated, the door 25 is provided with a peripheral flange 26 to fit over the flange' 21 and assist in sealing the opening 20, and,

for opening and closing movement, the door 482 25 is fixedlymounted on a horizontal rod or upper part of the casing.

into the caisson and to remove material therefrom, use is made of a bucket having a shaft 27 pivotally mounted in the ring 23 and projecting to the outer side of the ring where it is provided with an arm 28 carrying a counterbalance or weight 29 which constantsition.

The casing 19 is also provided at one side with a door opening 30 surrounded by an inwardly extending flange 31. The opening 29 1y urges the door 25 upwardlyto closed po- `is provided with a door 32 which, as indicated in Fig. 1, has a peripheral flange 33" cooperating with the flange 31.

Control of the pressure in the caisson is effected through a pipe 34 connected with the To lower material bail to which is attached a flexible rope 37 passing upwardly through the top of the casing, the arrangement being such as to avoid `ment gun nozzle 40 to which the desired mixture of cement and sand is supplied through the material hose 41, and water is supplied through a hose 42. The material ,hose 41 may be connected at its other kend with a nipple projecting downwardly from the flat annular portion 24 of the ring 23 and connected through portion 24 with a pipe or hose 45 connected 'in turn with the outlet valve of a cement gun. Preferably a valve 46 is provided in the connection between the pipe or hose and the hose 41. Similarly, the water hose 42 is connected through the flat annular portion 24 with a water sup 1y pipe 47 provided with a valve 48. Re erence has een made to a cement gun at the outside of the caisson, but it will be evident that the operation ma be performed by use of a cement gun at tlie interior of the caisson.

Under many conditions it is not necessary to seal the joints each time a sectional ring 1s added at the bottom of the caisson, but after a suitable number of rings havefbeen added a sheet `of reinforcin material 50, of suitable size wire and size o mesh to meet the requirements of the work, is applied and, as indicated in Fig. 1, is bent around the flanges to some extent to bring the portions in the spaces between the flanges closer to the side wall of the caisson. The reinforcin material thus applied may be secured in t is position by suitable means such as loops of wire connected with parts of the reinforcing material and extending around bolts 15 or nuts 16.

The sealing of the joints is effected by spraying the lhydrated mixture into place over and around the joints, thereby forming a.Y seal of cementitious material, such as Gunite. It is especially advantageous to use Gunite in that this material is very strong and will adhere to the caisson wall when sprayed thereagainst. Preferably, reinforcing material such as metal mesh 50 is applied over the anges at the joints and the hydrated mater al is blown into place to form a deposit 51 filling the space between the reinforcing material and the caisson members and covering the reinforcing material. The operation just described is repeated each time the depth of the caisson is increased to a predetermined extent, and until the caisson is completed.

Although, when the pressure maintained in the caisson is relatively low, it may be sufiicient to cover the oints only (Fig. 3) it is in general found desirable to line the caisson throughout (Fig. 3) with cementitious material, such as Gunite.

In the event that the joints only are to be covered (Fig. 3) strips 50a of reinforcing material are bent into position around the flanges 14 at the joints and material sprayed thereon to form the desired deposit 51. However, where the joints only are covered and the pressure is relatively high, there is danger of the seal being broken. For example, the air pressure at the outside of a portion of the caisson may, due to passage of air around the bottom of the caisson, be as great as at the inside, and if the pressure in the caisson falls suddenly the air at the outside might force its way inwardly and break the seal.

The seal shown in Fig. l has the advantage that the lining of the caisson is complete and, even if the air from the outside of the caisson came in between the caisson shell and the lining, it would be prevented by the lining from entering the caisson so as to reduce materially the air tight condition thereof.

As already stated, it is practically impossible to keep up the air pressure in the caisson v necessary to exclude water, unless the sealing of the joints is effected more expeditiously than by methods heretofore in use. Obviously it is impracticable to attempt to seal the joints by material requiring the use of forms. However, by use of a cement gun, cementitious material forming Gunite can be applied very quickly. Furthermore the Gunite adheres strongly to metal. Gunite is of especial value for this purpose in that the mixture of cement and sand blown by the cement gun to the nozzle is hydra-ted at the nozzle substantially without addition of excess water and is therefore immediately effective. I

It should be understood that various changes may be made and that parts of the invention may be used without others without departing from the true spirit and scope of the invention.

I-Ia-ving thus described my invention, I claim 1. The method of sinking a caisson under high internal air pressure which includes assembling ring sections into successive rings at the bottom of the caisson as soon as sufficient soil is removed to permit the addition of a ring, securing the sections of each ring together and to the next ring above as quickly as possible, and quickly sealing, at the interior of the caisson to enable the air pressure to be maintained, the joints at each newly formed portion of the caisson by blowing cementitious material into place over the joints.

2. The method of sinking a caisson under internal air pressure which includes 'assembling in successive interior-pressure-sustaining rings at the bottom of the caisson ring sections having at their edges inwardly extending fastening flanges, securing together the iianges brought together in assembling ring sections into a ring engaging the lower edge of a previously formed ring, and quickly sealing the joints of newly formed portions at the bottom of the caisson by applying sheets of mesh material over said flanges at the interior of the caisson depressing the mesh material between the flanges at opposite edges of the ring sections, and blowing hydrated cementitious material into place to embed said mesh material.

In witness whereof, I aiiix my signature.

LYMAN R. TALBOT.

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