JP2003148083A - Casing for shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a casing for a shaft, the press-in works of which can be conducted efficiently and the pull-out works of which can be conducted comparatively easily even when a shaft depth is increased. SOLUTION: The casing 1 and 10 for the shaft are formed by arranging airtight ballast tanks 3 and 30, into or from which a fluid is taken, on the inner circumferential surface of a cylindrical casing 2 in an approximately cylindrical body shape in the same axis as the cylindrical casing 2. The ballast tank 3 is formed so that the side face sections 31 and 3r of four segment-shaped airtight tank members 3a run parallel with the axial direction of the cylindrical casing 2 and the side face sections 31 and 3r of the adjacent tank members 3a are arranged so as to be mutually opposed. The ballast tank 30 is formed so that the side face sections 301 and 30r of four segment-shaped airtight tank members 30a having oblique wall sections 30b at lower end sections run parallel with the axial direction of the casing 2 and the side face sections 301 and 30r of the adjacent tank members 30a are arranged so as to be mutually opposed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft casing used for constructing a shaft in sewer construction, underground structure construction, well excavation, cast-in-place pile construction, and the like.

[0002]

2. Description of the Related Art When constructing a shaft in the ground for sewer construction, underground structure construction, etc., a cylindrical shaft casing such as a steel pipe is attached to the press-fitting head of a shaft excavator and press-fitted into the ground. In many cases, a method of discharging the press-fitted earth in the shaft casing to the ground using a grab bucket of the shaft excavator is used. In this construction method, when the shaft casing is press-fitted into the ground, work is performed by utilizing the weight of the shaft excavator and the weight of the casing.

Further, in the above-mentioned construction method, water is poured into the vertical shaft casing in order to balance the ground water spouting into the vertical shaft casing pressed into the ground and the earth pressure at the bottom of the vertical shaft, and the excavation work is performed underwater. Sometimes it is done.

On the other hand, there is a construction method in which the shaft casings press-fitted into the ground are left in the ground after the shaft construction, but after the shaft construction is completed, the shaft casing is pulled out from the ground and withdrawn. There is also. When pulling out the press-fitted casing for a vertical shaft from the ground, the pulling-out work is performed using a jack or the like equipped in the press-fitting head of the vertical shaft excavator.

[0005]

When press-fitting the shaft casing into the ground, the larger the weight of the casing, the more efficiently the press-fitting operation proceeds. Therefore, the deeper the shaft is, that is, the total length of the casing. The longer the length, the more advantageous for the press-fitting operation.

However, as the vertical shaft depth increases, the total length of the casing also increases, and the friction between the casing and the surrounding ground also increases, which makes it difficult to pull out the casing, and the casing is removed from the ground after the vertical shaft is constructed. However, it takes a lot of time and effort to pull out the work by jacking the press-fitting head of the vertical shaft excavator.

As described above, in the shaft excavation work using the casing for the shaft, it is advantageous that the casing weight is large when the casing is press-fitted, but the casing weight is small when the casing is pulled out. They tend to be in conflict with each other, which is advantageous, and the actual situation is that there is no appropriate countermeasure.

The problem to be solved by the present invention is to provide a casing for a vertical shaft which enables efficient press-fitting work and relatively easy pulling-out work even if the vertical shaft depth becomes large. It is in.

[0009]

The vertical casing of the present invention is characterized in that an airtight ballast tank capable of taking in and out a fluid is arranged on the inner peripheral surface of a cylindrical casing.

With such a structure, when the ballast tank is filled with a fluid having a large specific gravity such as water during the press-fitting work, the weight of the whole shaft casing increases, so that the press-fitting work can be performed efficiently. Since the weight of the shaft casing can be reduced by draining the fluid such as water from the ballast tank and filling it with a fluid having a small specific gravity such as air during the pulling operation, the vertical shaft depth can be increased. Even then, the pulling out work can be performed relatively easily. Further, when water is present in the shaft casing that is press-fitted into the ground, the airtight ballast tank filled with air receives buoyancy of water, and this buoyancy acts in the pull-out direction of the shaft casing. Therefore, the pulling out work can be further facilitated.

By arranging the ballast tank coaxially with the tubular casing in a substantially tubular shape, a work space near the center of the tubular casing is secured, and the earth and sand in the casing is discharged. Can be avoided.

Further, at the lower end portion of the ballast tank,
By providing a sloping wall surface that expands downward, various equipment such as grab buckets for discharging earth and sand that moves up and down in the casing will be caught on the lower end of the ballast tank arranged in a substantially cylindrical shape when rising. Can be prevented. If the vertical shaft casing is long and a plurality of ballast tanks are arranged adjacent to each other in the vertical direction (axial direction) of the casing, the sloping wall surface is the only ballast tank arranged at the bottom end of the casing. If it is provided in the above, the above-mentioned catching prevention function can be obtained.

On the other hand, by making the ballast tank attachable to and detachable from the inner peripheral surface of the cylindrical casing, the ballast tank can be removed from the casing when it is used in a construction method in which the casing is left in the ground after construction of a vertical shaft. Therefore, the entire space in the casing can be used as a vertical shaft, which is convenient, and the collected ballast tank can be attached to a new casing and reused, so that waste of materials can be reduced.

Further, by forming the ballast tank by a plurality of tank members that can be disassembled, it is possible to facilitate the work of attaching and detaching the ballast tank to the inner peripheral surface of the cylindrical casing and the work of transporting the ballast tank.

[0015]

1 is a vertical sectional view showing a vertical shaft excavating work using a vertical shaft casing according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 1 is a perspective view of a tank member constituting the ballast tank of the shaft casing shown in FIG. 1, FIG. 4 is a sectional view taken along line BB in FIG. 3,
FIG. 5 is a perspective view of a tank member that constitutes a ballast tank of the shaft casing located at the bottom in FIG. 1.

As shown in FIGS. 1 and 2, a vertical shaft casing 10 and two vertical shaft casings 1 are connected and press-fitted onto two cylindrical casings 2a which are sequentially connected to the ground G and press-fitted. Has been done. Vertical shaft casing 1, 10
Is formed by arranging airtight ballast tanks 3 and 30 capable of taking in and out fluid on the inner peripheral surface of the cylindrical casing 2 coaxially with the cylindrical casing 2 so as to form a substantially cylindrical body shape. .

The ballast tank 3 includes four airtight tank members 3a each having a segment shape as shown in FIG.
The linear side surface portions 3l, 3r are parallel to the axial direction of the cylindrical casing 2, and the side edge portions 3l, 3r of the adjacent tank members 3a are arranged so as to face each other to be formed into a substantially cylindrical body. ing.

The ballast tank 30 has four airtight tank members 30a each having a segment shape as shown in FIG.
0l and 30r are parallel to the axial direction of the cylindrical casing 2, and the side edge portions 30l and 30r of the adjacent tank member 30a.
Are arranged so as to face each other, and are formed into a substantially cylindrical body.

Further, as shown in FIGS. 3 and 4, the fluid inlet and outlet pipes 4 for filling and discharging the fluid into and from the tank member 3a on the side surface portions 3r and 3l of the tank member 3a, respectively.
5 are piped. The fluid inlet / outlet pipe 4 is piped on the uppermost portion of the one side surface portion 3r, and the fluid inlet / outlet pipe 5 is piped on the lowermost portion of the other side surface portion 3l. The fluid inlet / outlet tube 4 is for taking in / out air K, and the fluid inlet / outlet tube 5 is for taking in / out water W. Further, the fluid inlet / outlet pipes 4 and 5 having the same function as described above are also arranged at the same positions on the side surfaces 30r and 30l of the tank member 30a.

When the shaft casings 1 and 10 are press-fitted into the ground G, as shown in FIG.
When the water W is filled into the tank members 3a, 30a constituting the tank 30 via the fluid inlet / outlet pipe 5, the state shown in FIG. 1 is obtained, and the weight of the vertical shaft casings 1, 10 is increased. The press-fitting work can be performed efficiently. When the water W is filled through the fluid inlet / outlet pipe 5, the fluid inlet / outlet pipe 4 is opened to function as an air vent. The casing press-fitting work can be performed by a conventional method using a press-fitting head of a vertical shaft excavator.

Further, the work of discharging the earth and sand 6 in the cylindrical casing 2a located at the lowermost portion in FIG. 1 can also be carried out by a conventional method using a grab bucket 7 of a vertical shaft excavator or the like. In this case, it is also possible to inject water into the cylindrical casing 2a in order to balance the ground water and the earth pressure at the bottom, and perform the excavation work underwater.

Since the ballast tanks 3 and 30 are arranged coaxially with the cylindrical casing 2 in a substantially cylindrical shape, a working space near the center of the cylindrical casing 2 is secured,
It is possible to avoid adverse effects on the work of discharging earth and sand in the cylindrical casing 2.

Further, by providing the slant wall portion 30b at the lower end portions of the four tank members 30a constituting the ballast tank 30, the slant wall surface 30X whose diameter is expanded downward as a whole of the substantially cylindrical ballast tank 30. Is formed, the cylindrical casing 2a and the shaft casing 1,
It is possible to prevent various devices, such as the grab bucket 7 for discharging the sand and the like, that move up and down in the inside 10 from being caught on the lower end portion of the ballast tank 30 arranged in a substantially tubular shape when the device is raised.

In this embodiment, since the plurality of ballast tanks 3 are arranged in the vertical direction (axial direction) of the cylindrical casing 2 so as to be adjacent to each other, the ballast arranged at the lowermost end of the cylindrical casing 2 is arranged. Slope wall X only in tank 30
By providing, the function of preventing the grab bucket 7 or the like from being caught is obtained.

When the press-fitting work up to the planned depth is completed, the water W filled in the ballast tanks 3, 30 is discharged through the fluid inlet / outlet pipe 5 of each tank member 3a, 30a, and the fluid inlet / outlet pipe 4 is discharged. Each tank member 3a,
If air is flowed into 30a, the shaft casing 1,
Since the weight of the whole 10 is reduced, the pulling out work can be relatively easily performed even if the vertical shaft depth becomes large.

When the pulling operation is performed, as shown in FIG. 6, if water is present in the shaft casings 10 and 1 that are press-fitted into the ground, the water W is drained and the airtightness is reduced. The ballast tanks 3 and 30 receive the buoyancy of water, and this buoyancy acts in the pulling-out direction of the cylindrical casing 2 and the vertical shaft casings 1 and 10, so that the pulling-out work can be further facilitated.

Further, the ballast tanks 3, 30 are formed by a plurality of tank members 3a, 30a, and these tank members 3a, 30a can be attached to and detached from the inner peripheral surface of the cylindrical casing 2, so that after the vertical shaft is constructed. , Cylindrical casing 2
When used in the construction method in which is left in the ground G, the ballast tanks 3 and 30 can be removed from the cylindrical casing 2, so that the entire space in the cylindrical casing 2 can be used as a vertical shaft, which is convenient.

Further, since the tank members 3a, 30a of the recovered ballast tanks 3, 30 can be attached to a new casing and reused, waste of materials can be reduced.
Since these tank members 3a and 30a can be individually transported and attached to and detached from the inner peripheral surface of the casing, the transportation work and the attachment / detachment work are easy.

In this embodiment, the ballast tanks 3, 30
Is composed of four tank members 3a and 30a, respectively, but is not limited to this, and the number of tank members constituting the ballast tank can be increased or decreased according to the size of the cylindrical casing. Alternatively, a ballast tank having an integral shape can be used. Further, in the present embodiment, a vertical shaft having a depth in which five cylindrical casings 2a, 2 are connected is described, but the vertical shafts are not limited to this depth, and therefore, the number of vertical shafts depending on the required vertical shaft depth. The cylindrical casing 2a and the vertical shaft casings 1 and 10 can be connected.

[0030]

The present invention has the following effects.

(1) By arranging an airtight ballast tank capable of taking in and out a fluid on the inner peripheral surface of the tubular casing, the specific gravity of the fluid filled in the ballast tank is large and small, and Since the weight can be increased or decreased, the press-fitting work can be performed efficiently, and the pulling-out work can be performed relatively easily even if the vertical shaft depth increases. Further, if water is present in the vertical shaft casing that has been press-fitted, the ballast tank is filled with air or the like to generate buoyancy in water, so that the pulling operation can be further facilitated.

(2) By arranging the ballast tank in a substantially cylindrical shape coaxially with the cylindrical casing,
A work space near the center of the tubular casing can be secured, while avoiding adverse effects on the work of discharging earth and sand in the casing.

(3) At the lower end of the ballast tank,
By providing a sloping wall surface that expands downward, various equipment such as grab buckets for discharging earth and sand that moves up and down in the casing will be caught on the lower end of the ballast tank arranged in a substantially cylindrical shape when rising. Can be prevented.

(4) By making the ballast tank attachable to and detachable from the inner peripheral surface of the cylindrical casing, the ballast tank is removed from the casing in the construction method in which the casing is left in the ground after the construction of the vertical shaft. It is convenient because the space can be used as a shaft, and the collected ballast tank can be attached to a new casing and reused, so that waste of materials can be reduced.

(5) By forming the ballast tank with a plurality of disassembleable tank members, it is possible to facilitate the work of attaching and detaching the ballast tank to the inner peripheral surface of the cylindrical casing and the work of transporting the ballast tank.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing vertical shaft excavation work using a vertical shaft casing that is an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a perspective view of a tank member that constitutes the ballast tank of the vertical shaft casing shown in FIG. 1.

FIG. 4 is a sectional view taken along line BB in FIG.

5 is a perspective view of a tank member that constitutes a ballast tank of the shaft casing located at the bottom in FIG. 1. FIG.

FIG. 6 is a vertical cross-sectional view showing the operation of pulling out the casing for the vertical shaft after excavating the vertical shaft.

[Explanation of symbols]

1,10 Vertical shaft casing 2,2a Cylindrical casing 3,30 ballast tank 3a, 30a Tank member 3l, 3r, 30l, 30r Side part 4,5 fluid inlet and outlet pipes 6 earth and sand 7 grab bucket 30b Sloping wall 30x inclined wall G ground K air W water

Claims (5)

[Claims] 1. A vertical shaft casing in which an airtight ballast tank capable of taking in and out a fluid is arranged on the inner peripheral surface of a tubular casing. 2. The vertical shaft casing according to claim 1, wherein the ballast tank is arranged substantially coaxially with the cylindrical casing in a substantially cylindrical shape. 3. The vertical shaft casing according to claim 2, wherein a slant wall surface having a downward diameter is provided at a lower end portion of the ballast tank. 4. The vertical shaft casing according to claim 1, wherein the ballast tank is attachable to and detachable from the inner peripheral surface of the cylindrical casing. 5. The vertical shaft casing according to claim 1, wherein the ballast tank is formed of a plurality of disassembleable tank members.