JP2004250907A - Sole plate construction method of underground structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To thin a sole plate of an open caisson which is constructed under the surface of water, and to ensure quality stability and reliability of the sole plate as well. <P>SOLUTION: A first section room 9 having a bottom opening of a short span and a second section room 11 adjacent to the first section room through a partition wall 5 and having a bottom opening of a long span are formed in the ground. Then, a first sole plate 13 is formed in the first section room 9, and water inside thereof is drained out. A cylinder body 15 is placed in the second section room 11, and an underwater concrete is supplied to the second section room 11 to construct a second sole plate 21. After that, an opening section 23 is made in the partition wall 5, a hollow section 15a of the cylinder body 15 is connected to the first section room 9 through the opening section, and the hollow section 15a of the cylinder body 11 is used for an atmospheric space. Reinforcing work of the second sole plate 21 is carried out in the atmospheric space. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for constructing a bottom plate of an underground structure submerged in the ground, and is particularly useful as a method for building a bottom plate of an underground structure that is rooted under a water bottom or a groundwater surface.
[0002]
[Prior art]
The caisson method is often used when constructing revetments, piers, vertical piles, and other structures in the spring formations below the bottom of the water or groundwater. This caisson method is generally divided into a pneumatic caisson method and an open caisson method. Of these, the pneumatic caisson method is equivalent to the water pressure at each depth, which is the groundwater spring that becomes an obstacle when deeply excavating the ground. It is a construction method in which caisson is sunk by air pressure. On the other hand, the open caisson method is a method in which caisson is excavated and submerged under atmospheric pressure without using compressed air.
[0003]
The pneumatic caisson method requires workers to enter a closed high-pressure working room, which reduces work efficiency due to work time limitations to prevent latent illnesses and increases the size of machinery and equipment. There is a problem such as. In particular, as the depth of underground structures required in recent years increases, these problems tend to become more apparent.
[0004]
On the other hand, since the open caisson method is an operation under atmospheric pressure, all of these types of problems can be avoided. However, in the open caisson method, due to groundwater springs and the like, the inside of the entity is filled with water and welding becomes difficult, so it is difficult to make the bottom plate that seals the bottom of the entity into reinforced concrete, In many cases, it must be made of concrete. In this case, it is difficult to ensure the quality and reliability of the bottom board because the operator cannot directly confirm the concrete placement condition or the like. In addition, it is necessary to increase the thickness of the bottom plate in order to ensure the strength of the bottom plate, and it is necessary to reduce the utilization rate of the underground space and to further increase the depth to make up for this. In particular, under a large depth reaching several tens to several hundreds of meters, it is necessary to further increase the thickness of the bottom plate in response to an increase in the lifting pressure, and these adverse effects become even more remarkable.
[0005]
For example, Japanese Patent Application Laid-Open No. 11-181783 discloses a proposal for strengthening the bottom of an open caisson. In this method, ground reinforcing materials such as steel bars, steel pipes, and steel core mortar piles are embedded in advance in the ground bottom area of the caisson entity. However, even with this construction method, the bottom plate itself remains in an unreinforced state made of underwater concrete, and there is concern about the quality stability and reliability of the bottom plate.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-181783
[Problems to be solved by the invention]
In view of the above points, an object of the present invention is to reduce the thickness of an underground structure such as an open caisson where the construction of the bottom board is performed under the surface of the water, and also to ensure the quality stability and reliability of the bottom board. To do.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a method for constructing a base plate of an underground structure according to the present invention comprises: (1) a first compartment having a short-span bottom opening below the surface of the water, and a first compartment and a partition wall adjacent to each other. And a step of forming a second compartment having a long-span bottom opening under the water surface, (2) a step of draining the chamber after forming the first bottom plate in the first compartment, and (3) A step of forming an atmospheric pressure space communicating with the first compartment after drainage under the water surface of the second compartment, and a step of constructing a second bottom plate by supplying underwater concrete to the second compartment; And (5) a step of reinforcing the second bottom plate in the atmospheric pressure space. In addition, the construction order of each process is not limited to the order of (1) → (2) → (3) → (4) → (5), but can be arbitrarily changed as necessary.
[0009]
Of the two compartments, the first bottom plate formed in the short span first compartment has a short lifting span, so the lift pressure acting on the bottom plate is small, so even if it is constructed with unreinforced concrete, A thin one is sufficient.
[0010]
On the other hand, a large lifting pressure acts on the second bottom plate of the second compartment because it has a long span. However, in the present invention, because the reinforcement work for the second bottom plate is performed as described above, unreinforced concrete is used. Compared to this, the thickness of the bottom board can be greatly reduced.
[0011]
From the above, according to the present invention, it is possible to reduce the thickness of the bottom board in the entire underground structure.
[0012]
In the present invention, since the reinforcement work of the second bottom plate is performed in the atmospheric pressure space, the operator can visually check the construction status directly on site, and the quality and reliability of the bottom plate can be improved. .
[0013]
The communication between the first compartment and the atmospheric pressure space can be performed, for example, through an opening provided in the partition wall.
[0014]
The atmospheric pressure space can be formed, for example, in the inner space of a cylinder disposed in the second compartment. In this case, in addition to disposing a bottom base reinforcing material for reinforcing the bottom base inside the cylindrical body, the cylindrical body itself can be used as the bottom base reinforcing material by forming the cylindrical body with a rigid material.
[0015]
As the reinforcing work of the second bottom board, for example, an operation including a step of joining the bottom board reinforcing material arranged in the atmospheric pressure space to the underground structure can be considered. It is sufficient to reinforce the bottom plate as long as at least this step is included. Other steps, such as placing a bottom plate reinforcement in the atmospheric pressure space or placing concrete, are performed in parallel. May be. In addition, as the bottom base reinforcing material, for example, reinforced concrete (reinforcement or steel frame, or a concrete containing a combination thereof) is preferable, and thereby bottom base reinforcement using atmospheric concrete becomes possible.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a method for building a bottom plate of an underground structure according to the present invention will be described with reference to FIGS. As used herein, “underground structure” refers to a structure in which a part or all of the structure is incorporated. The type and application of the structure are not particularly limited, and include those manufactured with steel plates, steel pipes, etc., in addition to caisson. In the following description, an open caisson will be described as an example of an underground structure.
[0017]
As shown in FIG. 1 and FIG. 2, the caisson entity 1 used in the present invention has a cylindrical shape that is open at the top and bottom, for example, a cylindrical shape, and one or a plurality of partition walls 5 are arranged inside the main wall 3. (The illustrated example is a double wall structure in which one partition wall 5 is arranged inside the main wall 3). The main wall 3 is made of a rigid material such as reinforced concrete, and an outer blade edge 3a is formed at the lower end thereof. The partition wall 5 is comprised by the inner blade edge part 5a formed in the lower end, and the wall part 5b installed on the blade edge part 5a. The wall body part 5b consists of a steel sheet pile etc., for example, and is attached to the inner blade edge part 5a so that attachment or detachment is possible. The inner blade edge portion 5a is connected to the outer blade edge 3 via connecting portions 7 arranged at a plurality of positions in the circumferential direction on the outer side, whereby the partition wall 5 is firmly coupled to the caisson entity 1 (note that 3 to 9, the illustration of the connecting portion 7 is omitted). From the above configuration, the first compartment 9 having the bottom opening as the short span L1 is formed between the main wall 3 and the partition wall 5, and the bottom opening is longer than the span L1 inside the partition wall 5. A second compartment 11 having a span L2 is formed (L2> L1).
[0018]
The caisson entity 1 is submerged in the ground by excavating the ground of the first compartment 9. The subsidence force at this time depends not only on its own weight, but can also be used in combination with pressure input by a hydraulic jack or the like, if necessary. Further, the caisson entity 1 can be set up by constructing the whole on the ground and then sinking it into the ground, or by adding the frame 1 on the ground by the amount of sinking and repeating this procedure. When the caisson entity 1 sinks to a predetermined depth below the water surface, the ground of the second compartment 11 inside the partition wall 5 is excavated. Thereby, as shown in FIG. 1, the 1st division chamber 9 and the 2nd division chamber 11 are each filled with water (ground water, seawater, etc.).
[0019]
Next, as shown in FIG. 3, underwater concrete is supplied to the first compartment 9 to build a bottom board 13 (first bottom board). The first bottom plate 13 is made of unreinforced concrete without a reinforcing material such as a reinforcing bar. However, as described above, since the bottom opening of the first compartment 9 has a short span L1, an extreme increase in thickness is unnecessary. Even a thin wall can sufficiently resist the lifting pressure. After the construction of the first base 13, as shown in FIG. 4, the water in the first compartment 9 is drained with a pump or the like to make the first compartment 9 an atmospheric pressure region.
[0020]
Next, as shown in FIG. 5, a cylindrical body 15 that crosses the bottom opening is disposed at the bottom of the second compartment 9. The cylindrical body 15 is a formwork at the time of placing concrete, which will be described later, and is formed of a material suitable as a concrete formwork, such as wood or a resin material, and is formed in the second compartment 9 using, for example, a crane or the like. Is suspended at a predetermined position.
[0021]
The length of the cylindrical body 15 is set to a length close to the inner surface (the inner surface of the inner blade edge portion 5a in the illustrated example) of the partition wall 5 whose both ends are opposed to each other so as to suppress the leakage of underwater concrete. Further, in the vertical direction, the cylinder 15 is installed so that both ends of the cylinder 15 are located above the first bottom board 13. In this case, as shown in FIGS. 10A and 10B, the inner surface of the partition wall 5 facing the end of the cylindrical body 15 (in this embodiment, the inner blade) so that the cylindrical body 15 can be reliably installed at a predetermined position. It is desirable that a notch 17 is formed in the inner surface of the mouth portion 5a, and both ends of the cylindrical body 15 are fitted into the notch 17. Moreover, in order to prevent water from entering the inner space 15 a when sinking into the second compartment 11, it is desirable to seal both ends of the cylinder 15 with a lid 19 that can be easily attached and detached.
[0022]
Next, while maintaining the position / posture of the cylinder 15, as shown in FIG. 6, underwater concrete is supplied to the second compartment 11 to be cured and solidified, and the second bottom plate 21 containing the cylinder 15 is provided. Build.
[0023]
Next, as shown in FIG. 7, the opening 23 extends from the first compartment 9, which is an atmospheric pressure region, to the partition wall 5 (in the present embodiment, the inner blade edge 5 a) corresponding to both end positions of the cylindrical body 15. (If the both ends of the cylinder 15 are sealed with the lid 19, the lid 19 is removed), and the inner space 15 a of the cylinder 15 is connected to the first compartment 9 through the opening 23. Communicate with. As a result, the inner space 15a of the cylindrical body 15 becomes an atmospheric pressure space where workers can freely enter and exit. Therefore, a reinforcing member 24 made of a reinforcing bar, a steel frame, or the like is appropriately disposed in the atmospheric pressure space, and both ends thereof are appropriately disposed. By means, it is firmly connected to the entity 1 (for example, the inner blade edge 5a). At the same time, the cylinder 15 is removed, and a cavity corresponding to the shape of the cylinder 15 is formed inside the second bottom plate 21.
[0024]
The reinforcing member 24 in the atmospheric pressure space can be incorporated in the inner space 15a of the cylindrical body 15 in advance on the ground. In this case, in the atmospheric pressure space, it is only necessary to perform the work of joining the reinforcing member 24 to the substance and the concrete placing work, and the work efficiency can be improved.
[0025]
When the above operation is completed, concrete (shown as a dotted pattern) is placed in the cavity from the first compartment 9 through the opening 23, and this is cured and solidified. Thereby, the 2nd bottom board 21 becomes a reinforced structure in which the bottom board reinforcement 25 made of RC or SRC was built. Further, as shown in FIG. 8, the opening 23 of the partition wall 5 is sealed with concrete or the like (both ends of the reinforcing member 24 can be joined to the blade edge 5a by this sealing work).
[0026]
Thereafter, the interior of the second compartment 11 is drained, and the wall body portion 5b of the partition wall 5 is removed, so that the bottom opening of the substance has two types of bottom boards 13, 27 having different thicknesses as shown in FIG. An underground space sealed with is formed. In this case, the second bottom plate 21 is thicker than the first bottom plate 27 by at least the thickness of the bottom plate reinforcing material 25, and a step H is formed between the first bottom plate 13 and the second bottom plate 21. . In addition, if this drainage and the removal work of the wall part 5b are after building the 2nd bottom board 21 in the 2nd division chamber 11, and isolate | separating the 2nd division chamber 11 from the ground (stage shown in FIG. 6), Can be done at any time.
[0027]
As described above, in the present invention, the second bottom plate 21 of the long-span second compartment 11 which is a strength weak point is formed as the reinforced concrete in which the bottom plate reinforcing material 25 is contained. The bottom board thickness can be significantly reduced compared to the bottom board. Therefore, at the same time as improving the utilization rate of the underground space, it is not necessary to increase the depth for securing the underground space, and the construction cost can be reduced.
[0028]
Further, since an atmospheric pressure space communicating with the first compartment 9 through the opening 23 is formed in the second compartment 11, the installation work of the bottom board reinforcing material 25 in the second compartment 11 is performed. Alternatively, the bonding work of the bottom base reinforcement 25 to the substance can be performed under atmospheric pressure. Therefore, these operations can be performed by an operator while directly confirming visually, and the bottom board quality can be stabilized and the reliability can be improved.
[0029]
The construction according to the method of the present invention is not limited to the above description, and the embodiment can be changed as necessary. For example, the installation location of the bottom board reinforcing material 25 is not limited to one location, and may be a plurality of locations in the bottom opening of the second compartment 11. Further, the shape of the bottom plate reinforcing material 25 is arbitrary, and may be a rod shape as shown in the figure, or may be a united shape (for example, a star shape) by assembling a plurality of bottom plate reinforcing materials in a plane or three-dimensionally. it can.
[0030]
Moreover, in the said description, although the wall part 5a of the partition wall 5 is removed after construction of the 2nd bottom board 5b, it can also be left without removing this. In this case, the partition wall 5 can be made into an integral structure of the blade edge part 5a and the wall part 5b.
[0031]
Further, in the above description, the cylindrical body 15 is used only as a formwork and is removed after the second bottom plate 21 is constructed. However, the cylindrical body 15 is formed of a hollow rigid material such as a steel pipe or a steel box. Thus, it can be used as the bottom plate reinforcing material itself and can be left in the second bottom plate 21. In this case, the inner space of the cylinder 15 may be left as it is, but by filling it with reinforced concrete or the like, the bottom board strength can be further improved. Moreover, what united the cylinder 15 and reinforcement members, such as a reinforcing bar arrange | positioned on the outer side, can also be used as a bottom base reinforcement.
[0032]
In the above description, the case where the bottom plate is reinforced in the atmospheric pressure space after the second bottom plate 21 is constructed with underwater concrete is exemplified. After drainage, an opening 23 is formed in the partition wall 5 to form an atmospheric pressure space at the bottom of the second compartment 11 and the bottom plate reinforcing material 25 is constructed, and then the underwater concrete is supplied to the second compartment 11 The second bottom board 21 can also be built.
[0033]
In the above description, an underground structure having one second compartment 11 is illustrated, but the first compartment 9 and the second compartment 11 having a bottom opening with a long and short span are provided via the partition wall 5. In the case where it is continuous in a plurality of stages, a large continuous underground space partitioned alternately by the first bottom board 13 and the second bottom board 21 can be formed by repeating the above construction procedure. In this case, the first compartment 9 and the second compartment 11 do not necessarily have to be formed inside the caisson entity, and as shown in FIG. 11, a space sandwiched between the opposing wall surfaces of the adjacent caisson entities 1 and 1 is formed. It can also be used as these compartments. Incidentally, in FIG. 11, a space sandwiched between the main wall 3 of one caisson entity 1 and the main wall 3 of the other caisson entity 1 is defined as a second compartment 11 ′. The example which constructs 2nd bottom board 21 'reinforced with the bottom board reinforcement | strengthening material (illustration omitted) in the same procedure as is shown. In this case, the opposing main walls 3 and 3 serve as the partition wall 5 during the construction of the second bottom plate 21 ′. In addition, both the compartments 9 and 11 can also be formed by combining two or more single-wall caissons having only one blade edge portion 3a.
[0034]
In addition, the above construction procedure is not limited to the case where the thin first bottom board 13 and the thick second bottom board 21 are alternately installed, but also builds a continuous bottom board in which the bottom board thickness increases stepwise. The same applies to the case.
[0035]
FIG. 12 shows another embodiment of the present invention. This embodiment is an example in which an underground space is formed by a first entity 1 and a second entity 10 having different shapes.
[0036]
In this embodiment, first, the first entity 1 is sunk to a predetermined depth. The first entity 1 includes a main wall 3, a partition wall 5 and an intermediate blade 31 that are sequentially arranged in a direction away from the main wall 3, and the first entity 1 is provided between the main wall 3 and the partition wall 5. A single compartment 9 is formed, and a second compartment 11 is formed between the partition wall 5 and the intermediate blade 31. The main wall 3 and the partition wall 5 are coupled via the connecting portion 7, and the intermediate blade portion 31 is also coupled to the main wall 3 via a connecting portion (not shown). After the first entity 1 is sunk to a predetermined depth, the first bottom plate 13 of the first compartment 9 and the second bottom plate 21 containing the bottom plate reinforcing material 25 are built in the same procedure as in the above embodiment.
[0037]
Next, the second entity 10 is set at a predetermined pitch from the intermediate blade portion 31. The second entity 10 includes a main wall 3 ′ and a partition wall 5 ′ disposed inside the main wall 3 ′, and a blade edge portion 5 a ′ of the partition wall 5 ′ is connected via a connecting portion 7. It is connected to the main wall 3 '. In this case, a first compartment 9 ′ is formed between the main wall 3 ′ and the partition wall 5 ′, and a second compartment 11 ′ is formed between the partition wall 5 ′ and the intermediate cutting edge 31.
[0038]
After the second entity 10 is laid, the first base 13 'is built in the first compartment 9' in the same manner as in the above embodiment, and the room is drained. Thereafter, the second bottom plate 21 'is reinforced by the same procedure, and the second bottom plate 21' including the bottom plate reinforcement 25 'is built. At this time, the bottom board reinforcing material 25 ′ is also connected to the intermediate blade edge 31 using the atmospheric pressure space, and the two entities 1 and 10 are integrated.
[0039]
Thereby, the first entity 1 and the second entity 10 are rigidly coupled, and an underground space is formed inside these entities 1, 10. In the case where the first entity 1 and the second entity 10 are formed as a caisson integrally formed in advance, a large number of blade portions exist in one entity, so that the sinking resistance becomes excessive and it is difficult to set the two. It is possible to easily construct an underground structure having a vast underground space by performing the substituting work separately for the entities 1 and 10 as independent structures and then using the atmospheric pressure space to couple them together. It becomes possible.
[0040]
In addition, if the installation area is excavated in advance when the second entity 10 is submerged, the second entity 10 can be suspended and installed with a crane or the like, and the second entity 10 is submerged by excavating its inner ground. Compared to the case, the construction procedure can be simplified. In this case, a cylinder for installing the bottom base reinforcing material 25 ′ can be connected to the second entity 10 in advance on the ground, thereby further simplifying the construction procedure.
[0041]
【The invention's effect】
As described above, according to the present invention, the bottom plate of the underground structure can be thinned, and the bottom plate having high quality and reliability can be constructed.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a process of a bottom board construction method according to the present invention.
FIG. 2 is a cross-sectional view of an underground structure used in the present invention.
FIG. 3 is a longitudinal sectional view showing a process of the bottom building method according to the present invention.
FIG. 4 is a longitudinal sectional view showing the steps of the bottom board construction method according to the present invention.
FIG. 5 is a longitudinal sectional view showing a process of the bottom building method according to the present invention.
FIG. 6 is a longitudinal sectional view showing a process of the bottom building method according to the present invention.
FIG. 7 is a longitudinal sectional view showing the steps of the bottom board construction method according to the present invention.
FIG. 8 is a longitudinal sectional view showing a process of the bottom building method according to the present invention.
FIG. 9 is a longitudinal sectional view showing a process of the bottom building method according to the present invention.
FIGS. 10A and 10B are a cross-sectional view (a) and a vertical cross-sectional view (b) showing a fitting state between a cylindrical body and a notch. FIGS.
FIG. 11 is a longitudinal sectional view showing a continuous bottom board construction state.
FIG. 12 is a longitudinal sectional view showing another embodiment of the method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Caisson entity 3 Main wall 3a Blade edge part 5 Partition wall 5a Blade edge part 5b Wall part 7 Connection part 9 1st division chamber 11 2nd division chamber 13 1st bottom board 15 Cylindrical body 15a Inner space part 17 Notch 19 Lid Body 21 Second base 23 Opening 24 Reinforcement member 25 Bottom base reinforcement

Claims (5)

Forming a first compartment having a short span bottom opening below the water surface, and a second compartment adjacent to the first compartment via a partition wall and having a long span bottom opening below the water surface;
After forming the first bottom plate in the first compartment, draining the chamber;
Forming an atmospheric pressure space communicating with the first compartment after drainage under the water surface of the second compartment;
Supplying underwater concrete to the second compartment and constructing the second bottom plate;
And a step of reinforcing the second bottom plate in the atmospheric pressure space. The method for constructing a bottom plate of an underground structure according to claim 1, wherein the first compartment and the atmospheric pressure space are communicated with each other through an opening provided in the partition wall. The method for building a bottom plate of an underground structure according to claim 1 or 2, wherein the atmospheric pressure space is formed in an inner space of a cylindrical body arranged in the second compartment. The method for building a bottom plate of an underground structure according to claim 1, wherein the reinforcing work of the second bottom plate includes a step of joining a bottom plate reinforcing material arranged in the atmospheric pressure space to the underground structure. The method for constructing a bottom plate of an underground structure according to claim 4, wherein the bottom plate reinforcing material is reinforced concrete.

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