JP7688456B2 - Air Lock System - Google Patents

Description

The present invention relates to an air lock chamber used in the pneumatic caisson construction method.

In general, with the pneumatic caisson method, compressed air is pumped into a work chamber set up at the bottom of the caisson, and excavation work is carried out while the air pressure is used to expel groundwater. A material shaft and man shaft extend from the work chamber to the ground, with locks (air locks) such as material locks and man locks installed along the way. Material locks and man locks are usually made of steel and installed at the top of the shaft, but they may also be placed at the bottom of the shaft, directly above the work chamber slab.

One such type of lock (air lock chamber) is the bottom-locking manlock, made of reinforced concrete. This bottom-locking manlock made of reinforced concrete can be made larger in area than manlocks installed at the top, allowing workers to decompress in a relaxed position with their legs stretched out, which is known to help prevent decompression sickness.

Patent Document 1 also discloses an example in which a recovery lock is made of steel or prestressed concrete, has a semicircular or horseshoe-shaped cross section, and is configured to be assembled and disassembled.

JP 2010-150870 A

However, conventional manlocks made of cast-in-place reinforced concrete had the problem that removal took a long time because the reinforced concrete had to be crushed. Furthermore, the recovery lock in Patent Document 1 was attached to the workroom slab with anchor bolts, which could cause problems with the connection strength and airtightness.

In addition, when constructing a lock by placing precast blocks on top of a workroom, the applicants developed a lock structure in which numerous PC steel rods are arranged and tensioned to ensure airtightness and structural strength. However, the lock structure they developed was designed to use the workroom slab as the base when assembling the lock structure on top of the workroom slab. This caused problems with the joints between the side walls (partition walls, gable walls) and the workroom slab. In other words, unevenness occurred because the workroom slab was constructed using cast-in-place concrete. In order to correct (adjust) this unevenness, grout injection work was required.

Therefore, the present invention aims to provide an air lock chamber that does not require grout injection and has a small number of parts.

In order to achieve the above-mentioned objective, the air lock chamber of the present invention is an air lock chamber installed on a work chamber slab in a pneumatic caisson, and is composed of one or more box culverts made of precast concrete, one or more plates made of precast concrete, and multiple connecting mechanisms that detachably connect the one or more box culverts and the one or more plates.

In this way, the air lock chamber of the present invention is an air lock chamber in a pneumatic caisson that is installed on top of the work chamber slab, and is composed of one or more box culverts made of precast concrete, one or more plates made of precast concrete, and multiple connecting mechanisms that detachably connect the one or more box culverts and the one or more plates. With this configuration, by constructing the air lock chamber made of the box culverts and plates on top of the work chamber slab, grout injection work is not required, and an air lock chamber with a small number of parts is obtained.

This is a cross-sectional view of a pneumatic caisson cut along a vertical plane. FIG. 2 is an explanatory diagram of an air lock system according to an embodiment. FIG. FIG. 3 is a cross-sectional view of the air lock chamber taken along line AA in FIG. 2. FIG. 11 is an explanatory diagram of a first modified example of an air lock system. FIG. 11 is an explanatory diagram of an air lock system according to a second modified example.

The following describes an embodiment of the present invention with reference to the drawings.

(Configuration of pneumatic caisson)
First, the overall configuration of a pneumatic caisson 1 equipped with a manlock 2 as an air lock system of the present invention will be described with reference to Figure 1. As shown in Figure 1, a cutting edge 11 with a tapered tip is formed at the bottom of a side wall 10 of the pneumatic caisson 1, and a work chamber 13 is formed by being surrounded by the inner surface of this cutting edge 11 and the underside of a work chamber slab 12. At least one excavator (not shown) is disposed in the work chamber 13, and the pneumatic caisson 1 is lowered by excavating the ground with the remotely operated excavator.

A material shaft (not shown) extends from the workroom 13 toward the ground, with a material lock (not shown) installed at the top. An elevator shaft (man shaft) 14 also extends from the workroom 13 toward the ground, with man lock 2, an air lock chamber, installed at a distance from the side wall 10 at the bottom. In addition, although not shown, compressed air equipment is installed to supply and exhaust compressed air into the workroom 13 and man lock 2.

In addition, although not shown, a central monitoring room has been installed on the ground near the pneumatic caisson 1. The central monitoring room monitors and manages the entire construction, including the delivery of materials via the excavator, material shaft, and material lock, and the removal of excavated soil and sand, the entry and exit of workers via the elevator shaft 14 and manlock 2, pressure management such as pressurization and depressurization within manlock 2, and display of the caisson's sinking amount, tilt, and other posture.

(Manlock's composition)
Next, the configuration of the manlock 2 as the air lock system of this embodiment will be described. The manlock 2 is composed of two rooms, a main room 31 and an auxiliary room 32, which are square (rectangular) in plan view as a whole, arranged side by side in the horizontal direction. An anchor ring for installing a work room hatch is embedded in the bottom plate of the main room 31 as the air lock, and an anchor ring for installing the elevator shaft 14 is embedded in the top plate.

As shown in Figures 2 to 4, the Manlock 2 (air lock chamber) of this embodiment is divided into multiple box culverts 51-53 made of precast concrete and multiple plates 41-43 made of precast concrete, so that installation is simple and transportation, lifting and lowering with a crane are also easy. In other words, the Manlock 2 as an air lock chamber system of this embodiment is constructed by connecting the box culverts 51-53 and the plates 41-43, which form the gable wall, bottom slab and top slab, using a connecting mechanism 60.

The box culverts 51-53 are box-shaped (cubic) concrete structures, and because they are made of precast concrete, they have high dimensional precision. Furthermore, the box culverts 51-53 have a so-called PRC structure, in which prestressing steel is embedded in the top and bottom plates. Although not shown, water-stopping members are attached to the joint surfaces of the box culverts 51-53, and they can be water-stopped by pressing the surfaces together.

The two air lock chambers 31, 32 are partitioned by, from left to right, plate 41 which is the gable wall, upper box culvert 51 and lower box culvert 51, upper box culvert 51 and lower box culvert 51, plate 42 which is the bottom slab, box culvert 52 and box culvert 53 which are placed horizontally, and plate 43 which is the top slab.

The box culverts 51 to 53 in this embodiment are divided into two members in cross section. Specifically, as shown in FIG. 4(a), the main room 31 is divided vertically into two: an upper box culvert 51 with a top plate and left and right side walls, and a lower box culvert 51 with a bottom plate and left and right side walls. In other words, the upper and lower box culverts 51, 51 have the same shape. Furthermore, by connecting two of these combinations, the main room 31 is divided into four box culverts 51, ... as a whole. On the other hand, the auxiliary room 32 is divided horizontally into two: the box culvert 52 on the main room 31 side, which also serves as a partition wall, and the box culvert 53 on the auxiliary room 32 side, which also serves as a gable wall.

Furthermore, although not shown, it is preferable to provide mating recesses or mating protrusions for alignment on the joint surfaces between the box culverts 51 to 53. After the upper and lower box culverts 51, 51 are combined, they are connected vertically by a connecting mechanism 60. Similarly, after the left and right box culverts 52, 53 are combined, they are connected horizontally by a connecting mechanism 60.

As mentioned above, the box culverts 51 that make up the main room 31 have no embedded metal fittings or box cutouts, and all four of them can be of the same structure. By sharing parts in this way, the formwork can be reused during manufacturing. Furthermore, the overall length can be changed by increasing the number of units that are connected. However, if the box culverts are divided, they will not have the same structure.

The multiple plates 41 to 43 include plate 41, which serves as the gable wall, plate 42, which serves as the bottom plate, and plate 43, which serves as the top plate. Metal fittings for the work chamber hatch 15 are installed on plate 42, which serves as the bottom plate, and metal fittings for the elevator shaft 14 are installed on plate 43, which serves as the top plate.

The number of divisions of the box culverts 51-53 and plates 41-43 described above is not limited to the specific example. The number of divisions of these components is appropriately determined taking into consideration the size (span) of the manlock 2, size restrictions during transportation, and the lifting/suspension capacity of a crane. Depending on the size of the manlock 2, a culvert box that is integrally constructed within the cross section without being divided, as shown in Figure 4 (b), can also be used. When dividing, it is preferable to appropriately change the division position so that the joint surfaces (joints) between adjacent box culverts are arranged alternately (staggered).

In this embodiment, a connecting mechanism 60 is installed on the multiple box culverts 51-53 and plates 41-43 to detachably connect these multiple parts. Note that the number of connecting mechanisms 60 installed is not limited to the number shown in the figure, but is determined appropriately based on the required compressive force, strength, etc.

The connecting mechanism 60 can be made of PC steel (PC steel rods or PC steel strands) and fixing devices (couplers, if necessary) that connect general box culverts. Specifically, multiple sheath holes can be provided in the box culverts 51-53, and the PC steel rods inserted into the sheath holes can be fixed in place using fixing devices while a tensile force is applied by a jack. Note that the connecting mechanism 60 can also be made by a method other than using PC steel, for example, by connecting using high-strength bolts.

(How to build an air lock)
Next, a method for constructing an air lock chamber will be described. The method for constructing an air lock chamber includes the following steps 1) to 9).
1) Install the plate 42 that will serve as the base.
2) Install horizontal box culverts 52, 53 to serve as the auxiliary chamber 32.
3) The left and right box culverts 52, 53 are connected horizontally with PC steel bars.
4) Install the top plate 43.
5) Plate 42, box culverts 52, 53, and plate 43 are connected vertically with PC steel rods.
6) Install box culverts 51, etc. which will become the main room 31.
7) The upper and lower box culverts 51, 51 are connected vertically with PC steel rods.
8) Install the plate 41 that will serve as the gable wall.
9) The plate 41 and the box culverts 51, 51 are connected horizontally with PC steel rods.

- Vertical and horizontal PC steel rods can be used for joining and tensioning each time they are used, and can be connected with couplers, or multiple pieces can be joined at once.
After installing the bottom plate 42, install a dog-shaped hatch in the anchor ring.
After the top plate 43 is installed, the elevator shaft 14 is installed on the anchor ring. Note that a ladder-type man shaft may be installed instead of the elevator shaft 14.

(Method of dismantling and removing the air lock chamber)
- The method for removing an air lock chamber is to follow the steps of the construction method in reverse order.
After dismantling, the box culverts 51 to 53 and plates 41 to 43 have their joint surfaces cleaned and are stored in a designated location.

(Pressure/Depressurization)
Next, a procedure for pressurizing and depressurizing using the Manlock 2 of the embodiment will be described.
(Pressure)
・Pressurize and depressurize with the bulkhead door open.
・Pressurize at a specified speed, and depressurize according to the depressurization table. Pressurize or depressurize by sucking in helium mixed gas or oxygen gas as necessary.
When entering the box during pressurization or depressurization, close the partition door and return the room on the lifting equipment side (auxiliary chamber 32) to atmospheric pressure before entering the room, and after pressurization, enter the work chamber to perform work.
- After that, the room on the lifting equipment side (auxiliary room 32) is pressurized, and when the pressure is equal, the bulkhead door is opened to reduce the pressure to atmospheric pressure, and the vehicle is moved to the ground via the lifting equipment.

(effect)
Next, the effects achieved by the main chamber 31 and the auxiliary chamber 32 serving as air lock chambers in this embodiment will be listed and explained.
(1) As described above, the main chamber 31 and the auxiliary chamber 32 as the air lock chambers of this embodiment are air lock chambers installed on the work chamber slab 12 in the pneumatic caisson 1, and are composed of one or more box culverts 51-53 made of precast concrete, one or more plates 41-43 made of precast concrete, and a plurality of connecting mechanisms 60, ... that detachably connect one or more box culverts 51-53 and one or more plates 41-43. With this configuration, by constructing the manlock 2 composed of the box culverts 51-53 and the plates 41-43 on the work chamber slab 12, it is possible to obtain a manlock 2 that does not require grout injection work and has a small number of parts.

In other words, in the case of the main chamber 31 and auxiliary chamber 32 of the embodiment, because they have a factory-fabricated bottom plate separate from the work chamber slab 12, the parts can be joined together with high precision. In other words, by incorporating the bottom plate as part of the box culverts 51 to 55, there is no need to inject grout between them and the work chamber slab 12 as in the past.

In addition, compared to when precast blocks are used, there is no need to embed a large number of steel bars, so the structural impact on the work chamber slab 12 is reduced. Furthermore, compared to when precast blocks are used, the overall rigidity is higher. Also, there are fewer joints between parts, and the structure has excellent airtightness and watertightness. Furthermore, if the box culvert is of PRC structure, PC steel bars are embedded in the top and bottom plates, and the PC steel bars can be stored without being removed from the product even after removal, and there is no risk of the PC steel bars being damaged or corroded. Note that if the PC steel bars are positioned to protrude from the outer surface of the product, it is preferable to apply an anti-rust treatment to the PC steel bars.

- Furthermore, it is preferable that one or more box culverts 51-53 are constructed as a single unit within the cross section, or are constructed by dividing them into multiple components within the cross section. If they are divided, the Manlock 2 can be constructed without being affected by transportation constraints or the lifting/suspension capacity of the crane. Furthermore, by standardizing (matching) the height and width, the box culverts 51-53 can be unitized. For example, the same parts can be used in different locations. Furthermore, the overall length of the Manlock 2 can be changed by increasing or decreasing the number of box culverts 51-53 that are connected.

- Furthermore, one or more box culverts 51-53 and one or more plates 41-43 can be arranged adjacent to each other in the horizontal direction and connected horizontally by a connecting mechanism 60. This configuration allows horizontal movement between the main chamber 31 and the auxiliary chamber 32, making movement easier. This is particularly useful when transporting an injured person after depressurizing them.

- Furthermore, one or more box culverts 51-53 and one or more plates 41-43 can be arranged adjacent to each other in the vertical direction and connected vertically by a connecting mechanism 60. With this configuration, the planar area occupied by the main chamber 31 and the auxiliary chamber 32 is reduced, so that manlocks 2 can be placed even in pneumatic caisson 1 with a small cross-sectional area.

- Furthermore, it is preferable that the connecting mechanism 60 has, for example, a tension rod and a fixing device installed on at least one end of the tension rod. With this configuration, the connecting mechanism 60 can tighten and fix the box culverts 51-53 and the plates 41-43 to each other, and prevent air leakage from the joint surfaces. Furthermore, the connecting mechanism 60 can be easily attached and detached.

(2) Furthermore, the Manlock 2 as an air lock system of the embodiment can be composed of the multiple main chambers 31 and auxiliary chambers 32 linked together as described above, a work chamber hatch connected to the bottom slab of the main chamber 31, which is the first air lock of the multiple air lock chambers, and an elevator shaft 14 connected to the top slab of the main chamber 31, which is also the first air lock chamber. With this configuration, the work chamber hatch 15 and elevator shaft 14 can be concentrated in the auxiliary chamber 32, making it possible to pressurize and depressurize the large space of the main chamber 31.

- Furthermore, by stacking the box culverts 52 and 53 horizontally on the auxiliary chamber 32 side, the openings of the box culverts 52 and 53 can be reduced. In other words, by installing the box culvert 51 vertically on the main chamber 31 side, where no box cutting is required for the top and bottom plates, and installing the box culverts 52 and 53 horizontally on the auxiliary chamber 32 side, where box cutting is required for the top and bottom plates, the openings are reduced and the structure is superior.

Below, we will use Figures 5 and 6 to explain Manlock 2A-2B as an air lock system with a different configuration from that of Example 1. Note that the same reference numerals will be used to explain the same or equivalent parts as those explained in Example 1.

As shown in FIG. 5, in the Manlock 2A, the lock shaft 16 is connected to the plate 42 that forms the gable wall of the main room 31, and the lower end of the lock shaft 16 is connected to the work room 13. The inside of this lock shaft 16 can be pressurized and depressurized. The two box culverts 51, 51 have the same shape of closed cross section (not divided). The plates 41, 42 that form the gable walls are also of the same shape. In this way, by connecting the lock shaft 16 to the plate 42 that forms the gable wall, the same shape can be used for the box culverts 51. Furthermore, since no equipment is installed inside, the main room 31 can be made spacious.

And because the pressure can be reduced by the lock shaft 16, they can enter and exit the work room 13 as is. In other words, even if another member enters the work room 13 while the main room 31 is being depressurized, there is no need for them to be replaced, and the depressurization of the main room 31 can continue. Furthermore, once the depressurization is complete, they can leave the main room 31 and return to the ground via the lifting equipment (not shown).

Similarly, as shown in FIG. 6, the Manlock 2B is composed of a main chamber 31 and an auxiliary chamber 32, with a lock shaft 16 connected to a plate 43 that forms the gable wall of the auxiliary chamber 32, and the lower end of the lock shaft 16 is connected to the work chamber 13. The inside of this lock shaft 16 can be pressurized and depressurized. A total of four box culverts 51, 51 have the same shape of closed cross section (not divided). The plates 41 to 43 that form the gable walls and partitions are also of the same shape. In this way, by connecting the lock shaft 16 to the plate 43 that forms the gable wall, the same shape can be used for the box culverts 51. Furthermore, since no equipment is installed inside, the main chamber 31 and the auxiliary chamber 32 can be made spacious.

And because the pressure can be reduced by the lock shaft 16, it is possible to enter and exit the work room 13 as is. In other words, even if another member enters the work room 13 while the main room 31 or the auxiliary room 32 is being depressurized, there is no need for them to be replaced, and the depressurization of the main room 31 or the auxiliary room 32 can continue. Furthermore, once the depressurization is complete, the member can leave the main room 31 and return to the ground via the lifting equipment (not shown).

The rest of the configuration and effects are similar to those of Example 1, so a description will be omitted.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and design changes that do not deviate from the gist of the present invention are included in the present invention.

For example, the embodiment has been described as a case in which the main chamber 31 and the auxiliary chamber 32 serving as air lock chambers are constructed from box culverts and plates, but this is not limited to this, and for example, the entire structure can be constructed using only plates.

For example, in the embodiment, the directions in which the box culverts 51-53 and plates 41-43 are arranged are described as "horizontal" and "vertical" for convenience, but these are not strict definitions and even if there is some inclination, they are included in this concept. In that sense, they can also be called "approximately horizontal" and "approximately vertical".

1: Pneumatic caisson 10: Side wall 11: Cutter 12: Work room slab 13: Work room 14: Elevator shaft 15: Work room hatch 16: Lock shaft 2: Manlock (air lock system)
2A-2B: Manlock (air lock system)
31: Main room (air lock room)
32: Antechamber (Ki-lock room)
41-43: Plates 51-53: Box culvert 60: Connection mechanism 90: Pressure capsule

Claims (2)

In a pneumatic caisson, an air lock chamber is installed on the work chamber slab,
one or more box culverts made of precast concrete;
Several precast concrete plates;
The system is provided with an air lock chamber which is two linked manlocks , and which is composed of a plurality of connecting mechanisms for detachably connecting one or a plurality of the box culverts and a plurality of the plates;
The two air lock chambers are arranged in parallel in a horizontal direction via a partition wall to form a first air lock chamber and a second air lock chamber,
a work chamber hatch connected to the bottom plate of the first of the two air locks;
an elevator shaft connected only to the top plate of the first of the two locks;
An air lock system consisting of: In a pneumatic caisson, an air lock chamber is installed on the work chamber slab,
one or more box culverts made of precast concrete;
Several precast concrete plates;
The system is provided with an air lock chamber which is two linked manlocks , and which is composed of a plurality of connecting mechanisms for detachably connecting one or a plurality of the box culverts and a plurality of the plates;
A lock shaft connected only to the gable wall of a first air lock chamber of the two air lock chambers, the lock shaft being installed so as to penetrate the work chamber slab and communicate with the work chamber;
An air lock system comprising:

Images