JP3960690B2 - Caisson for construction of underground structures - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a caisson for construction of underground structures, and more particularly to a caisson having a groundwater flow blocking prevention means used to construct an underground structure such as a continuously extending tunnel.
[0002]
[Prior art]
FIG. 10 shows a conventional caisson for constructing an underground structure, wherein 1 is an underground structure, for example, a plurality of caissons arranged in a longitudinal direction to form a tunnel wall, and 2 is a side wall spaced apart from each other in the lateral direction. 3 is a bottom edge of the side walls 2 and 2 of each caisson 1, 4 a and 4 b are bottom plate beams and top plate beams connecting the side walls 2 and 2, 5 is the ground, and 6 is ground on the bottom 5 of the caisson 1. It is underwater concrete.
[0003]
Each caisson 1 is divided and constructed on the ground, submerged in the ground, built a retaining wall between adjacent caisons, and then excavated while preventing groundwater from flowing out by ground improvement work or pressure work. The caissons are connected to each other, and backfilling and removal of retaining walls are performed.
[0004]
[Problems to be solved by the invention]
However, in the conventional caisson, when the caisson is built in the aquifer by the submerged construction method, this caisson hinders the natural flow of groundwater in the ground, the upstream water level rises, and the downstream water level rises. There is a problem that it has a major impact on the surrounding environment, such as land subsidence and well water depletion.
[0005]
The present invention is intended to eliminate such problems.
[0006]
[Means for Solving the Problems]
The caisson for underground structure construction according to the present invention includes side walls that are spaced apart from each other, beams that connect the side walls, a water permeable filter that is attached to the outer surface of each side wall, and a water permeable filter that is provided on both side walls. It is characterized by comprising communication means for communicating the comrades so that water can be introduced, a gap layer formed between the water-permeable filter and the communication means, and a screen disposed between the water-permeable filter and the gap layer .
[ 0007 ]
The communication means comprises a water permeable filter.
[ 0008 ]
The gap layer is filled with a water permeable filter.
[ 0009 ]
The outer surface of the water permeable filter attached to the outer surface of the side wall is covered with a protective plate or a perforated sheet.
[ 0010 ]
The protective plate can be pulled up to the ground, and the outer surface of the lower end is covered with a cover provided at the lower portion of the side wall.
[ 0011 ]
The sheet is wound in a sheet storage magazine provided on the side wall, and the sheet is drawn out from the sheet storage magazine and covers a water permeable filter on the outer surface of the side wall.
[ 0012 ]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[ 0013 ]
Underground structures to which the present invention is applied, as shown in FIGS. 1 to 3, from the top to the outer surface of each side wall 2 of the caisson 1 up to the base portion of the lower end edge 3, the inner from the outer a predetermined width A protective plate 7 such as a thin steel plate, a water permeable filter 8 and a gap layer 9 are formed sequentially toward the gap, and the gap layer 9 on the one side wall 2 and the gap layer 9 on the other side wall 2 are opposed to each other. A communication pipe 10 is provided through the side wall 2 and the bottom slab beam 4a.
[ 0014 ]
The above-described caisson for constructing an underground structure allows groundwater to flow from the high side of the groundwater to the low side of the groundwater through the water permeable filter 8, the gap layer 9, and the communication pipe 10, and sinks the caisson. Even a natural flow of groundwater flow can be guaranteed.
[ 0015 ]
The communication pipe 10 may be provided on the top plate beam 4b instead of or in addition to the bottom slab beam 4a. Further, as shown in FIG. 4, a water permeable filter 11 made of ball gravel or the like is provided in the communication pipe 10. You may make it restrict | limit the flow velocity of the groundwater with which it fills and flows through the inside of the communicating pipe 10. FIG.
[ 0016 ]
In the present invention allowed to interposed a screen 12 between the permeability filter 8 and the gap layer 9 as shown in FIG.
[ 0017 ]
Further, as shown in FIG. 6, a water permeable filter 13 may be filled in the gap layer 9.
[ 0018 ]
The protective plate 7 outside the water permeable filter 8 is to prevent the water permeable filter 8 from being damaged by friction with the ground 5 when the caisson is set. It is necessary to make the material water-based. For this reason, for example, a perforated plate may be used as the protective plate.
[ 0019 ]
However, there is a possibility that the fine-grained soil of the ground 5 will block this hole during the installation. This clogging occurs particularly in the clay layer in the middle of settling.
[ 0020 ]
Therefore, it is preferable that the protective plate 7 can be removed after the completion of the setting.
[ 0021 ]
In addition, when it can be removed in this way, a protection plate without a hole can be used.
[ 0022 ]
Further, when the caisson sinks, the protection plate 7 and the water permeable filter 8 on the outside of the side wall 2 may be peeled off due to friction with the ground 5, but as shown in FIGS. 2 and 3, This can be prevented by pulling the protective plate 7 to the inside of the side wall 2 by the PC cable 15 through the provided through hole 14 and fixing it with the fixing metal fitting 16 inside the side wall.
[ 0023 ]
Further, as shown in FIG. 7, the outer surface of the lower end portion of the protective plate 7 may be covered with a cover 17 protruding from the lower portion of the side wall 2 by a fixing reinforcing bar 16 ′ embedded in the side wall 2.
[ 0024 ]
8 and 9, a sheet storage magazine 19 in which a protective sheet 18 is wound and stored is embedded in the lower end portion of the side wall 2, and the protective sheet 18 drawn out from the sheet storage magazine 19 is used as the protective plate. 7 is interposed between the water permeable filter 8 and the ground 5, and the protective sheet 18 is fed out according to the caisson settling. Thus, the permeability filter 8 can isolated from the ground 5, also it can be a very thin sheet this since no the protective sheet 18 is to be rubbed in the ground 5 or Ru can be formed by geotextile material.
[ 0025 ]
According to this embodiment, it is possible to prevent the water permeable filter 8 from being damaged during caisson sedimentation.
[ 0026 ]
【The invention's effect】
As described above, according to the caisson for constructing an underground structure of the present invention, it is possible to prevent the groundwater from being blocked by the caisson submergence and to ensure the natural flow of the groundwater flow.
[ 0027 ]
Further, if the sheet storage magazine is used, the water permeable filter can be protected during caisson sedimentation.
[Brief description of the drawings]
FIG. 1 is a longitudinal front view of a caisson for building an underground structure.
FIG. 2 is a longitudinal front view showing a main part of the caisson shown in FIG. 1;
3 is a cross-sectional plan view of the main part of the caisson shown in FIG. 1. FIG.
FIG. 4 is a longitudinal front view showing a main part of another caisson.
FIG. 5 is a cross-sectional plan view of the main part of the caisson for constructing an underground structure according to the present invention .
FIG. 6 is a cross-sectional plan view showing a main part of a caisson according to another embodiment of the present invention.
FIG. 7 is a longitudinal sectional front view showing a main part of a caisson according to another embodiment of the present invention.
FIG. 8 is a longitudinal sectional front view showing a main part of a caisson according to another embodiment of the present invention.
9 is a cross-sectional plan view showing the main part of the caisson shown in FIG.
FIG. 10 is a front view of a conventional caisson for constructing underground structures.
[Explanation of symbols]
1 Underground structure (caisson)
2 Side wall 3 Lower edge 4a Bottom plate beam 4b Top plate beam 5 Ground 6 Underwater concrete 7 Protective plate 8 Permeable filter 9 Gap layer 10 Communication tube 11 Permeable filter 12 Screen 13 Permeable filter 14 Through hole 15 PC cable 16 Fixing bracket 16 'Fixing rebar 17 Cover 18 Protection sheet 19 Sheet storage magazine

Claims (8)

And opposing side walls mutually apart from, a beam for connecting the side wall, and permeability filter attached respectively to the outer surface of the side walls, and communication means for communicating the permeability filter comrades of the both side walls to be water guide, the A caisson for construction of an underground structure comprising a gap layer formed between a water permeable filter and the communication means, and a screen disposed between the water permeable filter and the gap layer .   2. The caisson for construction of underground structures according to claim 1, wherein the communication means comprises a water permeable filter. The caisson for construction of underground structures according to claim 1 or 2, wherein the gap layer is filled with a water permeable filter. Claim 1, 2 or 3 underground structures built caissons according to, characterized in that the outer surface of the permeable filter attached to the outer surface of the side wall is covered by a protective plate. 5. The caisson for building an underground structure according to claim 4 , wherein the protective plate is a sheet. The caisson for constructing an underground structure according to claim 4 or 5, wherein the protection plate can be pulled up to the ground. The sheet is wound in a sheet storage magazine provided in the side wall, the sheet is pulled out from the sheet storage magazine, or claim 5, characterized in that covering the permeability filter of the sidewall outer surface 6 Caisson for construction of underground structure as described. Claim 4, 5, 6 or 7 underground structures built caissons according to, further comprising a protective plate bottom cover provided in the side wall lower to cover the lower end outer face of the protective plate.

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