JPH04336123A - Cut-off wall for caisson - Google Patents

Abstract

PURPOSE:To simply and quickly construct a cut-off wall provided at the crown of a caisson body, to facilitate its withdrawal and to obtain high cut-off ability. CONSTITUTION:A PC-steel bar 11 is inserted through pre-cast concrete long blocks 9a-9d severally having a vertical through hole 10, and its lower end is detachably locked to an anchor plate 12 buriedly provided in the parapet 4 of the upper part of the caisson, and its upper end is locked to an anchor plate 13 at the upper end of the block, and the steel bar 11 is wholly tensely drawn. A water swelling sealant is provided between the blocks serially provided in parallel, and the lower end of the block and the crown of the caisson body. In addition to that, the block serving as a key is formed with a longitudinal draft taper, and the block adjacent to the above key block is formed with a taper opposite to that of the key block.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-stop wall for a caisson provided at the top end of a caisson body.

0002

BACKGROUND OF THE INVENTION One of the construction methods for constructing the foundations of bridge piers, etc. is the caisson construction method, in which the inside of a well-shaped structure is excavated and then submerged. FIG. 15 shows an outline of the caisson construction method, in which 1 is the caisson body, 2 is the cutting edge formed at the lower end of the caisson body 1, 3 is the side wall, 4 is the parapet, 5 is the bottom plate,
6 is the top, and 7 is a pier constructed on top of the top 6.

By the way, as shown in the figure, when the top of the caisson is sunk below the water surface or the ground surface, the caisson itself is It is necessary to provide a water cutoff wall 8 as a temporary structure at the top of the wall 1.

Conventionally, the water stop wall 8 has been constructed at the top end of the caisson body 1 using cast-in-place concrete, steel sheet piles, steel materials such as H-shaped steel, or the like.

[0005]

[Problem to be solved by the invention] However, with cast-in-place concrete, removal at deep locations is done using blasting, etc.
There is a possibility that it cannot be completely removed. In addition, steel materials are difficult to connect to the top of the caisson body, and there are problems with water-stopping properties. Furthermore, both cast-in-place concrete and steel materials are troublesome to construct, the construction speed is slow, and the process is long.

SUMMARY OF THE INVENTION An object of the present invention is to provide a water-stopping wall for a caisson which eliminates the disadvantages of the conventional example, can be easily and quickly constructed, is easy to remove, and provides high water-stopping properties.

[0007] In order to achieve the above-mentioned object, the present invention has a water-stop wall provided at the top end of a caisson body, in which a PC is installed in a precast concrete vertical block having vertical through holes at the top and bottom.
A steel rod is inserted through it, and its lower end is removably locked to an anchor plate buried in the parapet at the top of the caisson, and its upper end is locked to an anchor plate at the top of the block to tension the entire block, and the blocks are connected in parallel. A water-swellable sealing material is provided between each block, the lower end of the block, and the top end of the caisson body, and the key block has a longitudinally drawn taper, and the adjacent blocks are opposite to the key block. The gist is that a taper is formed.

[0008]

[Function] According to the present invention, the precast concrete vertical blocks are tensioned in the longitudinal direction by PC steel rods to prevent them from lifting when the caisson is sunk, and between the blocks and between the lower end of the block and the top of the caisson body. The water-swellable sealant prevents water leakage. Also, each block can be pulled out by releasing the tension on the PC steel bar and pulling it out, but the key block in particular has a drawing taper in the length direction, so if you pull it out from this key block, Each block can be easily pulled out.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional side view of a main part showing one embodiment of a water stop wall for a caisson according to the present invention, FIG. 2 is a side view of the entire same, and FIG. 3 is a partial plan view of the same. Since the entire caisson is the same as that described with reference to FIG. 15, the description will be omitted.

In the present invention, as shown in FIG. 3, precast concrete vertical blocks 9a, 9b, 9c,
Use 9d. These blocks 9a, 9b, 9c, 9
d has through holes 10 at the top and bottom, and this through hole 10
A PC steel rod 11 is inserted through the PC steel rod 11, and the lower end of the PC steel rod 11 is removably locked with a nut to an anchor plate 12 embedded in the parapet 4 on the upper part of the caisson. Also,
An anchor plate 13 is also provided at the upper end of the blocks 9a, 9b, 9c, and 9d, and the upper end portion of the PC steel rod 11 is locked with this anchor plate 13, and each block 9a, 9d is
Tension b, 9c, and 9d in the length direction. Note that a water-swellable sealing material 14 was disposed between the lower end of each block 9a, 9b, 9c, and 9d and the top end of the caisson body.

The blocks 9a, 9b, 9c, and 9d are arranged in parallel to form a water-stop wall 8, and as shown in FIG. A water-swellable sealing material 14 was also provided between the joint surfaces. Furthermore, joint portions 16, which are joint locations, are filled with mortar 17.

Among the blocks 9a, 9b, 9c, and 9d, the block 9a constitutes the straight portion of the water stop wall 8, and as shown in FIGS. 11 and 12, the block 9a has a rectangular cross section and the same width at the top and bottom. be. Further, the block 9b constitutes a curved portion of the water stop wall 8, and as shown in FIGS. 13 and 14, the upper and lower sides have the same width, but have a trapezoidal cross section with sloped sides.

The block 9c is a key block, and has a rectangular cross section as shown in FIGS. 8 to 10, but the width at the top is large and the diameter gradually decreases toward the bottom, and there is a hole in the length direction on one side. A taper β is formed. On the other hand, the block 9d is a block adjacent to the key block 9c, and has a rectangular cross section as shown in FIGS. A reverse taper α corresponding to the above-mentioned drawing taper α is provided at the part.
was formed.

Next, the construction method will be explained. First, to explain the installation, when constructing the parapet 4 of the caisson body, an anchor plate 12 that can withstand the tension required when sinking the caisson is embedded. 19 in the figure is a grit line for reinforcement.

As shown in FIG. 2, a shoring 22 is assembled using struts 20 and ribs 21. In addition, each block 9a, 9
A joint plate 24 having an anchor 23 is disposed on the joint surface of the abdominal ribs 21 of b, 9c, and 9d, and this joint plate 2
4, the support bracket 25 of the abdominal stand 21 is attached.

[0016] Water-swellable sealing material 1 is placed on the top of the parapet 4.
4 is pasted, and water-swellable sealing material 14 is similarly pasted on the sides of each block 9a, 9b, 9c, and 9d.

In this way, each block 9a, 9b,
9c and 9d are installed and tensioned with PC steel rod 11. In this case, block 9c, which is the key block, will be the final built-in block. After the construction is completed, mortar 17 is placed between the blocks to improve the watertightness of the joints.

Next, removal will be explained. After construction of structures such as pier 7, the shoring 22 is removed and backfilled, P
Pull out the C steel bar 11 in the opposite direction. Then, the blocks 9c, which will become the key block, are pulled out in order using a multi-pulley, vibro hammer, or the like. At that time, as shown in FIG. 2, each block 9a, 9b, 9c, 9d is provided with a hole 26 that penetrates in the horizontal direction near 1 m below the top, and this hole 26 is used to make each block 9a, 9b , 9c, and 9d.

[0019]

Effects of the Invention As described above, the caisson water stop wall of the present invention uses vertically long blocks made of precast concrete, so it can be constructed easily and quickly.
The caisson is tensioned in the length direction by C steel rods to prevent it from floating up when it is sunk, and the water-swellable sealing material between the blocks and between the bottom end of the block and the top of the caisson body prevents water leakage, making it watertight. The value will be high.

Furthermore, by releasing the tension on the PC steel rod and pulling it out, each block can be pulled out. In particular, the key block has a drawing taper in the length direction, so it can be pulled out from this key block. By pulling out
Each block can be easily pulled out.

The water stop wall of the present invention can be applied to both open caissons and pneumatic caissons, and is particularly effective in press-fit caissons because the press force can be transmitted through concrete blocks. .

[Brief explanation of drawings]

FIG. 1 is a vertical sectional side view of the main parts of an embodiment of a water-stop wall for a caisson according to the present invention.

FIG. 2 is an overall side view showing one embodiment of a water-stop wall for a caisson according to the present invention.

FIG. 3 is a partial plan view of an entire embodiment of a water-stop wall for a caisson according to the present invention.

FIG. 4 is a cross-sectional plan view showing a joint between blocks.

FIG. 5 is a partially cutaway front view of a block adjacent to the key block.

FIG. 6 is a cross-sectional view of the upper end of the block adjacent to the key block.

FIG. 7 is a cross-sectional view of the lower end of the block adjacent to the key block.

FIG. 8 is a partially cutaway front view of the key block.

FIG. 9 is a sectional view of the upper end of the key block.

FIG. 10 is a sectional view of the lower end of the key block.

FIG. 11 is a partially cutaway front view of another block.

FIG. 12 is a cross-sectional view of another block.

FIG. 13 is a partially cutaway front view of still another block.

FIG. 14 is a sectional view of yet another block.

FIG. 15 is a sectional view showing an outline of the caisson construction method.

[Explanation of symbols]

1...Caisson body 2
…Blade mouth 3…Side wall
4... Parapet 5... Bottom plate
6... Top 7... Pier
8...
Water-stop walls 9a, 9b, 9c, 9d...Block 10...Through hole 11...PC steel rod
12, 13... Anchor plate 14... Water-swellable sealing material 15
...Shape steel 16...Joint part
17...Mortar 18...Anchor bar
19...grit muscle 20...
strut beam

Claims (1)

[Claims] [Claim 1] In the water stop wall provided at the top end of the caisson body, a PC steel rod is inserted into a precast concrete vertical block having through holes at the top and bottom, and its lower end is attached to and detached from an anchor plate buried in the parapet at the top of the caisson. The upper end is secured to the anchor plate at the upper end of the block to tension the whole block, and water-swellable sealing material is applied between the blocks that are connected in parallel and between the lower end of the block and the top of the caisson body. A water stop wall for a caisson, characterized in that the key block has a longitudinally drawn taper, and the block adjacent thereto has a taper opposite to that of the key block.