JP3833602B2 - Underground structure and its construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an underground structure in which at least a part of an underground wall such as a water barrier wall, an underground pile, a basement, an underground tank, a quay, a bridge pier, and a foundation are constructed in the ground, and a method for constructing the underground structure. Is.
[0002]
[Prior art]
As a method for constructing the underground structure, a construction method (division method) is known in which a plurality of segments produced in advance are joined while excavating the underground to construct the structure. As an example of this construction method, for example, Japanese Patent Laid-Open No. 8-120597 (Patent Document 1) discloses an underground tank construction method using a plurality of segments, and Japanese Patent Laid-Open No. 9-242461 (Patent Document 2). Also discloses a method for constructing a vertical pile using a plurality of segments.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 8-120697 [Patent Document 2]
Japanese Patent Laid-Open No. 9-242461
[Problems to be solved by the invention]
When constructing with the above-mentioned split construction method, it is possible to use segments that have been produced in advance at the factory, etc., and there is no need for concrete placement and curing, so the construction period can be shortened compared to general reinforced concrete construction, and construction is also possible. There is an advantage that the space can be reduced.
[0005]
On the other hand, in the conventional split method, the structure is extended in the depth direction by digging the inner ground of the existing segment and adding a new segment to the lower end of the existing segment. It is necessary to hang the segment from the ground to the middle, and the construction equipment such as a crane becomes larger, resulting in a further increase in cost.
[0006]
This problem can be solved by a so-called press-in method (press-in caisson method) in which an underground structure is constructed by press-fitting a box constructed on the ground into the ground. However, when the box is divided into segments, there is concern about the strength and rigidity of the joints between the segments, so it is difficult to adopt a press-fitting method in which a strong press input acts on the box.
[0007]
Accordingly, an object of the present invention is to make it possible to build an underground structure having a segment structure by a press-fitting method and to enjoy the advantages of both methods.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an underground structure according to the present invention includes a blade edge portion, a press-fit strut erected on the blade mouth portion, and disposed above the blade mouth portion and on the outer periphery of the press-fit strut. And a wall body part formed by combining a plurality of segments, and at least the blade edge part is press-fitted into the ground by excavation of the inner periphery of the wall body and application of pressure input to the press-fit post. It is characterized by this.
[0009]
As described above, the underground structure having a plurality of segments includes a step of forming a blade edge, a step of standing a press-fit post on the blade, and an outer periphery of the press-fit post above the blade edge. In addition, a step of forming a wall body portion connected to the press-fit struts by combining a plurality of segments, excavating the inner periphery of the wall body portion, and applying pressure input to the press-fit struts to press-fit at least the blade edge portion into the ground It can be built by a method including a process.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a caisson box is taken as an example of the underground structure, and an embodiment of the construction method will be described with reference to FIGS. In the following description, a caisson box having a hollow cylindrical shape with both upper and lower ends opened is taken as an example (see FIG. 5), but the shape of the box is not particularly limited.
[0012]
First, as shown in FIG. 1, the blade edge portion 1 is constructed in a circular shape in the planned installation area of the caisson. At this time, the blade edge portion 1 is constructed through a conventional process, that is, a series of processes such as rebar processing / assembly, formwork production / assembly, concrete driving / curing, and formwork removal. Next, a plurality of press-fit struts 2 made of H-section steel or the like are erected at appropriate positions (for example, at equal intervals in the circumferential direction) on the blade edge 1. The press-fit post 2 has a length such that the upper end of the press-fit post 2 is located slightly above the upper edge of the completed box, and the upper end of the press-fit post 2 is positioned on the same plane. The lower end portion of the press-fit strut 2 is embedded in the blade edge portion 1 or fixed to the blade edge portion 1 using an appropriate fixing fitting (the illustrated example illustrates the case where it is embedded in the blade edge portion 1).
[0013]
Next, as shown in FIG. 2, a plurality of segments 3 are stacked using a crane or the like above the blade edge portion 1 and on the outer periphery of the press-fit support column 2 to form a cylindrical wall body portion 4 composed of a combination of segments. In this embodiment, each segment 3 has a shape in which the wall portion 4 is divided by a horizontal dividing line at a plurality of vertical positions and further divided by a vertical dividing line at a plurality of circumferential positions. In the illustrated example, a case where the vertical division is performed in five stages is illustrated, and the segments 3 of each stage are denoted by reference numerals 3a, 3b,. After the segments 3a to 3e are stacked, the upper end of the press-fit support column 2 protrudes from the upper edge portion thereof.
[0014]
At least one of the segments 3a to 3e is connected to the press-fit strut 2. Here, the connected state is such that each segment 3a to 3e can follow the descending movement of the box due to the press-fitting of the press-fitting support column 2, specifically, the segments do not separate or fall off due to friction with the ground due to the press-fitting. The strength is sufficient and can withstand vertical pressure input generated by the press-fitting means 6 to be described later. The connecting means for connecting the segments 3a to 3e and the press-fit support column 2 is not particularly limited, and can be connected using bolts, appropriate metal fittings, or the like as long as the above conditions are satisfied. The material, composition, etc. of each segment 3a-3e are also suitably determined according to the kind, purpose, use, etc. of an underground structure, For example, a concrete segment and a steel segment can be used. As the steel segment, in addition to using a dedicated product separately manufactured according to the shape and structure of the target underground structure, a ready-made product such as a steel sheet pile can also be used.
[0015]
The segments 3a to 3e do not necessarily have to be directly connected to the press-fit struts 2, but indirectly by connecting to other members (for example, other segments) directly connected to the support column 2. It can also be in a connected state. In the example shown in FIG. 5, only the opposite end portions of two segments 3 adjacent in the circumferential direction are connected to one press-fitting support column 2, but the connection state is not limited to this, for example, the circle of the segment 3 Both ends in the circumferential direction can be connected to the press-fitting support column 2. Furthermore, you may connect upper and lower segments.
[0016]
When the wall 4 is required to resist against earth pressure or water pressure, concrete is placed with reinforcing materials such as reinforcing bars on the inner and / or outer periphery of the segments 3a to 3e. To do. Thereby, since the wall part 4 becomes a concrete structure and each segment 3a-3e is completely integrated with the press-fit support | pillar 2, the rigidity improvement of the wall part 4 can be aimed at. Thus, when making the wall part 4 into an integral structure, each segment 3a-3b does not necessarily need to be connected with the press-fit support | pillar 2, and if any part of the wall part 4 is connected with the press-fit support | pillar 2, It ’s enough.
[0017]
After the box 9 is completed by the above steps, the press-fitting equipment 5 is disposed above the press-fitting support 2 as shown in FIG. The press-fitting equipment 5 includes a pressure girder 7 mounted on at least two press-fitting struts 2 and a plurality of jacks 6 (preferably center hole jacks) disposed at both ends of the pressure girder 7. The jack 6 is disposed at a position where the caisson can be press-fitted in a well-balanced manner, and the rod 6a penetrates the presser girder 7 so as to move up and down and is placed as an anchor in the ground. The press-fitting equipment 5 can be arranged in parallel with the construction of the wall body portion 4 shown in FIG. 2 or before the construction of the wall body portion 4 (immediately after the step shown in FIG. 1).
[0018]
Next, the jack 6 is activated in the direction in which the rod 6a is raised, and the pressure girder 7 is pushed down. Thereby, the pressing force of the jack 6 is transmitted to the blade edge portion 1 via the press-fit post 2, and the blade edge portion 1 is pressed into the ground. Further, the box 9 is press-fitted to the final settling surface by excavating the inner periphery of the wall 4 while driving the jack 6. In such a press-fitting process, it is desirable to supply an appropriate liquid lubricant between the outer peripheral surface of the box 9 and the ground to improve the sliding of the caisson. Thereafter, if the press-fitting equipment 5 is removed, an underground structure having an underground space 8 is obtained as shown in FIGS. 4 and 5 (the underground structure having a solid structure by filling the underground space 8 with concrete or the like thereafter). Can also be a thing).
[0019]
In FIG. 4, the case where all the parts of the wall body part 4 are embedded in the ground is illustrated, but only a part of the wall body part 4 (lower part) or only the blade edge part 1 is embedded in the ground. Even in this case, the same procedure can be adopted.
[0020]
As described above, in the present invention, when the underground structure is press-fitted, the pressure input is mainly transmitted to the blade edge portion 1 through the press-fitting support column 2, and the pressure input is applied to the segments 3 a to 3 e constituting the wall body portion 4. Almost no effect. Therefore, it becomes possible to build the wall part 4 of the segment structure inferior in rigidity and strength by the press-fitting method, and it is possible to enjoy the advantages of the press-fitting method and the advantages of the segment structure. That is, it is possible to build an underground structure in a short construction period and at a low cost in a small construction space.
[0021]
Although the case where each segment 3a-3e is arrange | positioned in the outer periphery of the press-fit support | pillar 2 was illustrated in the above embodiment, the position which arrange | positions the segments 3a-3e is not limited to this. For example, as shown in FIGS. 6 (a) and 6 (b), the wall body portion 4 can be constructed by disposing the segments 3 a to 3 e on the flange back surface of the press-fit support column 2 made of H-shaped steel.
[0022]
Moreover, the division | segmentation aspect is not restricted to what was demonstrated by the said embodiment, For example, as shown in FIG. 7, the several segment 3 divided | segmented to the orthogonal | vertical direction can be joined, and the wall part 4 can also be constructed | assembled. In FIG. 2, division is performed using horizontal and vertical dividing lines, but cylindrical segments divided only by horizontal dividing lines may also be used. If the dividing lines in the vertical direction and the horizontal direction are not in a straight line shape as illustrated, but in a stepped shape, the strength of the wall portion 4 can be further improved.
[0023]
Furthermore, in the said embodiment, although all the segments 3a-3e are piled up and the wall body part 4 is completed, the press injection into the ground is started, but as shown in FIG. After the first segment (3a in the illustrated example) is stacked, before the upper segment (3b in the illustrated example) is stacked, press-fitting work is performed for the stroke corresponding to the height of the lower segment 3a, and then the upper segment 3b can also be arranged on the lower segment 3a. In this way, the process of stacking the upper segment on the existing segment and the process of applying the press input to the press-fit support column 2 and performing the press-fit operation are alternately performed, so that all the segments are stacked near the ground surface. Can do. Accordingly, the stacking operation of the segments 3a to 3e is facilitated, and a large crane or the like for lifting the segments at a high place is not necessary.
[0024]
FIG. 9 shows another embodiment of the press-fitting equipment, and is an example in which the jack 6 is not placed on the pressurizing girder 7 but suspended from the pressurizing girder 7. In this case, the support portion 10 that supports the jack 6 ′ is disposed below the upper edge portion of the box 9 via the suspension member 11, and the jack 6 ′ is attached on the support portion 10. . The rod 6a of the jack 6 penetrates the support portion 10 and is driven as an anchor on the ground. In this case, when the jack 6 ′ is driven, the pressure input is received by the support portion 10, and is transmitted to the blade edge portion 1 through the hanging member 11, the pressurizing girder 7, and the press-fit post 2.
[0025]
In places with restrictions on the head, such as under the road or indoors, the building height of the box is inevitably limited. Therefore, in order to increase the box height, after completion of the first press-fitting operation, the press-fitting equipment 5 is removed and the upper edge of the box 9 is extended upward, and then the press-fitting equipment 5 is rearranged for the second time. It is necessary to perform the press-fitting work, resulting in a longer construction period and higher costs. On the other hand, with the press-fitting equipment 5 shown in FIG. 9, the built-up height of the box 9 can be increased by the height of the jack 6 even under the limit of the empty head, and such inconvenience can be avoided. .
[0026]
In this case, as shown in FIG. 10, if a notch 13 is formed at the upper edge of the box 9 and the pressure beam 7 is arranged in the notch 13, the height of the pressure beam 7 is further increased. Since the construction space above the box 9 can be reduced, the building height of the box can be increased to the limit.
[0027]
The structure shown in FIGS. 9 and 10 is not limited to the case where pressure input is applied to the press-fit strut 2 shown in FIGS. 1 to 8 but also the press-fit strut 2 as shown in FIG. The present invention can be similarly applied to a construction method in which an input directly acts on the box 9.
[0028]
In the above description, the case where the present invention is applied to the setting of a cylindrical caisson box is illustrated, but the scope of application of the present invention is not limited to this, and an underground structure having a wall portion of a segment structure. Can be widely applied to. The shape of the underground structure is not limited to a cylindrical shape, and may be a planar wall shape.
[0029]
【The invention's effect】
As described above, according to the present invention, even an underground structure having a segment structure can be constructed by the press-fitting method, and the advantages of both methods that have been difficult to achieve together can be enjoyed together. Therefore, it is possible to construct underground structures, particularly deep underground structures, in a shorter construction period and at lower cost, and the required construction space can be further reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first step in building an underground structure according to the present invention.
FIG. 2 is a cross-sectional view showing a second step in building an underground structure according to the present invention.
FIG. 3 is a cross-sectional view showing a third step in building an underground structure according to the present invention.
FIG. 4 is a cross-sectional view showing a completed underground structure.
FIG. 5 is a plan view of a completed underground structure.
FIG. 6 is a plan view showing another embodiment of the underground structure.
FIG. 7 is a plan view showing another embodiment of the underground structure.
FIG. 8 is a cross-sectional view showing another example of the underground structure building method according to the present invention.
FIG. 9 is a cross-sectional view showing another example of the underground structure building method according to the present invention.
FIG. 10 is a cross-sectional view showing another example of the underground construction method according to the present invention.
FIG. 11 is an enlarged side view showing another example of the underground structure building method according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cutting edge part 2 Press-in support | pillar 3 Segment 4 Wall part 5 Press-in equipment 6 Press-in means (jack)
7 Pressing girder 8 Underground space 9 Caisson box 10 Supporting part 11 Hanging member 13 Notch

Claims (2)

A blade body portion, a press-fit strut erected on the blade mouth portion, a wall body portion that is disposed above the blade mouth portion and on the outer periphery of the press-fit strut, is connected to the press-fit strut, and is a combination of a plurality of segments A ground press-fitting structure characterized in that at least the blade edge part is press-fitted into the ground by excavation of the inner periphery of the wall body part and application of pressure input to the press-fitting strut. A method of constructing an underground structure having a portion composed of a plurality of segments,
The step of forming the blade edge, the step of standing the press-fit post on the blade mouth, and the wall body connected to the press-fit post by combining multiple segments above the blade and on the outer periphery of the press-fit post And a method of constructing an underground structure including excavating the inner periphery of the wall body portion and applying a pressure input to the press-fit post to press-fit at least the blade portion into the ground.

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