JP2000336946A - Reinforcing method for columnar structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method in which reinforcing works by the external- surface covering of a columnar structure are conducted in a short period at a low cost. SOLUTION: In a reinforcing method in which the external surface of the columnar structure is covered with steel-plate blocks, split steel plate members are applied onto the external surfaces of piers 3 as the columnar structures, steel plate blocks 5 are assembled by joining the joint sections of each split steel plate member, the steel plate blocks 5 are pushed down a and penetrated into a ground by a jack 10 for pressing-in for a press-in device 4 fixed to the upper sections of the piers 3, and the external surfaces of the piers 3 are covered with a plurality of the steel plate blocks 5 by repeating the assembly of the steel plate blocks 5 and the pushing-down operation of the blocks 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing (repairing) bridge piers and foundations (for example, concrete piles, steel pipe piles, etc.), chimneys and other columnar structures.

[0002]

2. Description of the Related Art Viaduct piers and other pillars (or piles)
For structures, to improve the seismic resistance of this columnar structure,
To repair cracks caused by earthquakes, various repairs,
Reinforcement has been made.

[0003] In particular, in the case of concrete piers that occupy the majority of the objects to be reinforced, the main causes of collapse due to the earthquake are deformation of the cross-sectional shape due to cracks or the like as an initial cause, and expansion of the pile outward from the outer peripheral surface. The strength of the pile is reduced due to the outburst.
If the outer peripheral surface of the pile is constrained by a material with a certain strength so that the initial cross-sectional shape can be maintained even by horizontal force, the original strength of the concrete pile can be maintained and the strength of the existing concrete pile However, it has been clarified through computer simulations and experiments that it can withstand the magnitude of the Hanshin Earthquake.

[0004] As a conventional reinforcing method performed from the above viewpoint, there is the following method. The periphery of the columnar structure is covered with a steel plate, and concrete,
A method of filling a filler such as mortar or resin. A method in which a formwork is arranged around a columnar structure, and concrete is poured into a gap between the formwork and the columnar structure. The strength against bending is increased by attaching the reinforcing carbon fiber sheet vertically around the columnar structure, and the shear force is increased by attaching the shear reinforcing carbon fiber sheet horizontally from above. The present invention relates to the above-described improvement.

More specifically, the method of covering the periphery of the columnar structure with a steel plate includes a method of winding a steel plate around the columnar structure with a strip-shaped steel plate, and a method of connecting both end joints of a half-split steel member with bolts. In some cases, it is necessary to reinforce the part where the columnar structure is buried in the ground, A work space is formed by excavating a relatively deep and wide area around a buried columnar structure, and reinforcement work is performed in this work space to cover the periphery of the columnar structure with a steel block.

[0006]

When a columnar structure is reinforced with a steel plate block as described above, in order to reinforce the underground portion, the underground around the structure is excavated relatively deeply and widely. There is a disadvantage in that a lot of time, labor, and cost are required for the work of forming the work space and for filling the work space after the work is completed, which leads to an increase in the cost of reinforcement.

[0007] The present invention is an improvement of the above-mentioned conventional reinforcing method.
It is another object of the present invention to provide a reinforcing method for covering the outer surface of a columnar structure with a steel plate block without excavating a wide working space.

[0008]

In order to achieve the above object, the present invention is configured as follows. The invention according to claim 1 is a reinforcing method of covering an outer surface of a columnar structure with a steel plate block, wherein the divided steel plate block is applied to an outer surface of the columnar structure, and a joint portion of each member is joined. After assembling the steel plate block, the steel plate block is pushed down by the press-fitting jack of the press-fitting device fixed to the upper part of the columnar structure to enter the ground, and assembly of the steel plate block and repetition of the pushing-down operation are repeated. The outer surface of said columnar structure is covered with said steel plate block. According to a second aspect of the present invention, in the first aspect of the present invention, the cylinder and the operating rod of the press-in jack are respectively provided in an upper chuck for a press-in reaction force and a lower chuck for urging a pressing force which are detachable from the columnar structure. The plurality of steel plate blocks are connected by expanding and contracting the press-in jack, and performing timing operations of fixing and opening the upper chuck and the lower chuck, thereby causing the press-in device to perform a repetitive operation of vertical movement along the columnar structure. Is characterized in that it is depressed. According to a third aspect of the present invention, in the first or second aspect of the present invention, the connecting means between the upper and lower steel plate blocks is a bolt or a weld. The invention of claim 4 provides claims 1 to 3
In any one of the inventions, the tip steel plate block provided at the lowermost end has a cutting edge portion at a lower portion, and an abrasive for brushing the outer periphery of the columnar structure is provided inside the cutting edge portion. . According to a fifth aspect of the present invention, in any one of the first to third aspects of the present invention, a lower portion of a tip steel plate block provided at a lowermost end is opened between the columnar structure and the columnar structure. And the earth and sand entering the gap between the steel plate block and the soil and the sand originally existing around the columnar structure and remaining around even after pushing down the steel plate block are washed and discharged with high-pressure jet water injected from above the gap. It is characterized by the following. According to a sixth aspect of the present invention, in any one of the first to third aspects of the present invention, high-pressure jet water is injected into a gap formed between the outer surface of the columnar structure and the steel plate block to exist in the gap. After the slime is stirred, mortar is injected into the gap while discharging the slime.

According to the present invention, a plurality of steel plate blocks can be formed by mounting a steel plate block on a columnar structure during ground work and repeatedly pressing down the steel plate block with a jack of a press-fitting device fixed to the columnar structure. While press-fitting into the ground, the steel sheet block is used to reinforce the coating over the required length of the outer surface of the columnar structure, as in the past,
It is not necessary to excavate the ground around the columnar structure deeply and widely to provide a work space.

[0010]

Embodiments of the present invention will be described below with reference to the embodiments. FIG. 1A is a longitudinal sectional front view showing the state of reinforcement work on a pier as a specific example of a columnar structure for implementing the reinforcing method of the present invention, and FIG. 1B is a longitudinal sectional view of FIG. FIG. 2A is a cross-sectional explanatory view, and FIG.
(B)-(b) cross-sectional explanatory view in FIG.
2A is an enlarged sectional view of a portion (C), FIG. 3C is an enlarged sectional view of another example of the portion (C) in FIG.
4 is a front view of the press-in device, FIG. 4 is a side view of FIG. 3, FIG. 5 is a cross-sectional plan view of the press-in device mounted on the pier, and FIG. 6 is a pier of the press-in device having a chuck fastening mechanism different from FIG. 7 (A) and 7 (B) are perspective views of a steel plate block at the tip (lowest end) and a standard steel plate block connected above the steel plate block, respectively, and FIG. FIG. 8 is a perspective plan view of another example of the steel plate block, FIG. 9 is a perspective view of still another example of the steel plate block, and FIG.
16 to 16 are construction process diagrams.

The description will be made in the following order. In FIG. 1A,
The bridge girder 2 on which the floor slab 1 is installed on the upper surface is one or more piers arranged side by side in the direction perpendicular to the bridge axis (three examples are shown in the figure).
3 is supported. The figure shows the construction procedure of the reinforcing method according to the method of the present invention, in which the leftmost pier 3 (3a) shows the situation before construction, the middle pier 3 (3b) shows the situation during construction, and the leftmost pier 3 (3b) shows the situation during construction. Pier 3 (3c) shows the situation after completion of construction.

When the pier 3 is reinforced, a hydraulic jack-type press-fitting device 4 is fixed to the foot of the pier 3 as shown in the middle pier 3b in FIG. The plurality of steel plate blocks 5 fitted to the pier 3 by expansion and contraction are sequentially pushed down along the pier 3 and pressed into the ground. The recess 8 in FIG. 1 (A) illustrates a shallow scaffold for work, and is not a deep and wide excavation work space as in the related art.

The structure of the jack-type press-fitting device 4 and the steel plate block 5 will be described with reference to FIGS. The jack-type press-fitting device 4 includes an upper chuck 6 for press-fitting reaction force, a lower chuck 7 for urging (and ascending) for press-fitting, and a jack 10 for press-fitting which connects the upper and lower chucks 6 and 7. ing.

Since the upper chuck 6 and the lower chuck 7 have the same structure, the upper chuck 6 will be described below, and the same elements of the lower chuck 7 as those of the upper chuck 6 will be denoted by the same reference numerals and description thereof will be omitted. . In the example shown in FIGS. 3 to 5, the upper chuck 6 is configured such that one end of an arc-shaped divided frame 11, which is divided into right and left, is hingedly connected by a connecting shaft 12. A chuck jack 1 capable of freely tightening and releasing between the two divided frames 11, 11 on both brackets 13, 13 provided at the other end.
4 is detachably provided to both brackets 13, 13 via a connecting pin 15.

Accordingly, the connecting pin 15 is detached from the pin hole, the left and right divided frames 11, 11 are separated from each other at the tip of the circular arc, sufficiently opened and applied to the outer surface of the pier 3, and The outer surface of the pier 3 is tightened and fixed to the outer surface of the pier 3 by the split frames 11 and 11 by expanding and contracting the chuck jack 14 again, or the tightening is released to free the pier 3. It can be in a state. This is the same for the lower chuck 7.

Each divided frame 1 in the upper chuck 6
The cylinder side of the press-fitting jack 10 is connected to the lower surface side of the intermediate portion of the press-fitting jacks 1 and 11 by a connecting pin 16. The operating rod 17 side is connected by a connecting pin 18.

Therefore, the chuck jack 14 is used.
The press-fitting device 4 is moved up and down in a predetermined range along the pier 3 as described later by performing the telescopic operation of the press-fitting jack 10 and the telescopic operation of the press-fitting jack 10 at a predetermined timing. Thus, the plurality of steel plate blocks 5 having a predetermined length can be sequentially pushed down to cover the entire length of the pier 3 in the vertical direction.

As shown in FIG. 6 as another example, each of the divided frames 11, 1 divided into right and left portions of the upper chuck 6 is provided.
Both ends of 1 may be configured to be openable and closable by the same connection structure as the chuck jack 14 shown in FIG. (Note that in FIG. 6, the same elements as those in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted.)

Examples of the steel plate block 5 are shown in FIGS. In the example shown in FIG. 7, the cylindrical steel plate block 5 is vertically divided in half, and the divided steel plate members 19, 19 having a substantially semicircular shape on the left and right are combined. A joint joint vertical flange 21 having a plurality of bolt insertion holes 20 is provided on both side edges of the pier 3. The two separate steel plate members 19, 19 are opposed to each other to sandwich the pier 3, and the joint vertical joint flange 21 is provided. , 21 are connected by connecting bolts 22 inserted into the bolt insertion holes 20 to assemble the steel plate block 5 and hold the pier 3.

In the lowermost tip steel plate block 5a, a split type taper guide having an enlarged diameter at an upper end is provided at a lower end of each of the split steel plate members 19, 19 so that the steel plate block 5a comes first and smoothly enters the ground. The portion 23 is fixed by welding 24 via the lower horizontal joining flange 32a. Also,
As schematically shown in FIG. 1B, the tapered guide portion 23
An abrasive 25 such as a wire brush or a wire mesh for brushing the outer peripheral surface of the bridge pier 3 when the steel plate block 5a is pressed down is disposed inside the steel.
The upper part of 5 is pressed by a flat-arc-shaped pressing plate 27 welded 26 to the lower ends of the inner peripheral surfaces of the divided steel plate members 19, 19. As shown schematically in FIG. 1C, the lower portion of the tip steel plate block 5a is opened between the outer peripheral surface of the pier 3 and the pier 3 and the steel plate block 5
The earth and sand 47 entering the gap 39 with a may be provided so as to be washed and discharged with high-pressure jet water injected from above the gap 39. Further, the split steel plate members 19, 19
A friction cutter 28 having a semicircular shape on each of the left and right sides is fixed by welding 29 to the outer peripheral surface. An upper horizontal joint flange 30 for joining the lower end of the upper standard steel plate block 5b is provided on the upper end edge of the divided steel plate members 19, 19 toward the outside, and has a bolt insertion hole 31. I have.

As shown in FIG. 7B, each standard steel plate block 5b to be joined above the tip steel plate block 5a does not have the taper guide portion 23 and the friction cutter 28 in the tip steel plate block 5a. The point is different from the tip steel plate block 5a, and the other configuration is the same as the tip steel plate block 5a.

In the example shown in FIG. 7, the lowermost end and the steel plate blocks 5a and 5b thereabove contact the upper horizontal joint flange 30 and the lower horizontal joint flange 32 of each block. By fastening, the upper and lower steel plate blocks 5a, 5b can be sequentially joined in the up-down direction while being added. In the example shown in FIG. 7, the upper horizontal joint flange 30, the lower horizontal joint flange 32, and the joint flanges 21, 21 of the steel plate blocks 5a, 5b are all protruded outside the divided steel plate members 19, 19. However, on the contrary, the flanges 30, 32, and 21 may be provided to protrude inward. (However, not shown)

FIG. 8 shows another example of the steel plate block 5. The upper and lower horizontal joint flanges 30 and 32 in FIG. 7 are not provided at the upper and lower edges of the steel plate blocks 5a and 5b in this figure, and instead, welding 33 is provided between the upper and lower steel block 5a and 5b. And joined sequentially upward. Other configurations are the same as the configurations of the steel plate blocks 5a and 5b in FIG. FIG. 9 shows still another example of the steel plate block 5, in which upper and lower steel plate blocks 5a,
5b is joined not only by welding 33, but also by welding 33 between the two split steel plate members 19,19. In addition,
Which of the steel plate blocks 5 shown in FIGS. 7, 8, and 9 should be used should be selected and used in consideration of the circumstances of the construction site.

Next, the construction procedure will be described by dividing it into items [1] to [31]. [1] As shown in FIGS. 1A and 1B, a press-fitting device and a hanging girder 33 for assembling a steel plate block are installed. [2] As shown in FIG. 2, the divided frames 11 and 11 in the upper chuck 6 and the lower chuck 7 are connected by using a chuck jack 14, and the press-fitting device 4 is assembled. Temporary support at the time of assembling the press-fitting device 4 is performed by suspending the hoist 34 or a chain block (not shown) described later. [3] As shown in FIG. 2, the tip steel plate block 5a is assembled. This work involves bolting and rust-preventive painting, and the work is carried out by using a wire 36 unwound from a hoist 34 suspended from and supported by hoist beams 35 provided at both ends of a suspension girder 46. This is performed by suspending and supporting the block 5a. [4] The divided frames 11, 11 of the upper chuck 6 in the press-fitting device 4 are fixed to the head of the existing pier 3 by shortening the chuck jack 14. (See FIG. 10A.) [5] The divided frames 11 of the lower chuck 7 in the press-fitting device 4 are opened by extension of the chuck jack 14. (See FIG. 10A) [6] The press-fitting jack 10 is extended, and the divided frame 11 of the lower chuck 7 is lowered. (See FIG. 10 (A)) [7] The divided frames 11 of the lower chuck 7 in the press-fitting device 4 are fixed to the head of the existing pier 3 by shortening the chuck jack 14. (See FIG. 10 (B)) [8] The split frames 11 of the upper chuck 6 in the press-fitting device 4 are opened by extension of the chuck jack 14. [9] By shortening the press-fitting jack 10, the upper chuck 6 is lowered. Thereafter, the steps [7] to [9] are repeated until the process reaches the lower steel plate block 5a or 5b. (See FIG. 10 (B).) [10] Further, by repeating the steps [7] to [9], the upper chuck 6 at the time of extension of the press-fitting jack 10 is extended.
Then, the steel plate block 5 is pressed into the ground using the lower chuck 7 as a press-down frame. (FIG. 11 (A)
[11] When the press-fitting jack 10 is extended to the maximum and the press-fitting of one steel plate block 5 is completed, the press-fitting jack 10 is shortened while the frame of the lower chuck 7 is open.
(See FIG. 11B) [12] The lower chuck 7 is fixed. (See FIG. 12 (A)) [13] The divided frames 11, 11 of the upper chuck 6 are released by extension of the chuck jack 14. (FIG. 12
(See (A)) [14] The upper chuck 6 moves upward by extending the press-fitting jack 10. (See FIG. 12A) [15] The upper chuck 6 is fixed to the pier 3. (FIG. 12
[16] Release the lower chuck 6 from the pier 3. (FIG. 12
(17) [17] By shortening the press-fitting jack 10, the lower chuck 7 is raised. Thereafter, the steps [12] to [17] are repeated until the press-fitting device 4 returns to the original position. (See FIG. 12B) [18] The standard steel plate block 5b is assembled. This assembling work includes bolting and rust-proof painting. (Figure 1
[19] The bolting of the joint vertical joint flange 21 of the upper and lower steel plate blocks 5 (or alternative joint welding) is performed. (See FIG. 13 (A)) [20] The standard steel plate block 5b is press-fitted in the same procedure as in the steps [4] to [17]. (See FIG. 13 (A).) [21] If the entire set of the tip steel plate block 5a and the plurality of standard steel plate blocks 5b reaches a predetermined settling length, the press-fitting device 4
To dismantle. (See FIG. 13 (B)) [22] The upper standard steel plate block 5b on the ground which is not press-fitted is suspended by the hoist 34 and temporarily supported to assemble. (See FIG. 13B) [23] The chute 37 is assembled. (See FIG. 14A)
As shown in FIG. 14 (C), a width stopper 38 is welded to the inner surface of each steel plate block 5 to secure a gap 39 between the pier 3 and the steel plate block 5. [24] High-pressure jet water is injected into the gap 39 between the pier 3 and the steel plate block 5 while pulling down the injection lot 40 which is an injection pipe for both high-pressure jet water and mortar.
Stir the slime inside. (See FIG. 14B) [25] While raising the injection lot 40, mortar 42 (shown in FIG. 15B) is injected from the injection lot 40, and the slime in the gap 39 is simultaneously discharged. (See FIG. 15 (A)) [26] Mortar injection is finished to a height of −30 mm to −50 mm from the upper part of the upper standard steel plate block 5 c shown in FIG. 15 (A). (See FIG. 15B) [27] The shoot 37 is dismantled. (See FIG. 15B) [28] Assemble the uppermost steel plate block 5d. (FIG. 15
(See (B)) [29] Sealing treatment 4 on top of top steel plate block 5d
Apply 1. (See FIG. 16 (A)) [30] FIG. 16 (A) while bleeding air from a small hole (not shown) in the upper part of the uppermost steel plate block 5d in FIG. c) As shown in FIG.
5 Non-shrink mortar 43 is injected into the gap in the uppermost steel plate block 5d from the arrow (g). (Refer to FIG. 16 (A)) [31] The press-fitting device 4 and the hanging girder 33 for assembling the steel plate block 5 are disassembled to complete the construction. (Refer to FIG. 16 (B).) In the illustrated example, an example of the concrete pier 3 is shown as a specific example of the columnar structure, but the present invention can be similarly applied to steel pipe piles and the like.

[0025]

As described above, according to the present invention, when covering the outer surface of a columnar structure with a steel plate block over its entire length in the vertical direction and reinforcing the steel plate, the steel plate block is mounted on the columnar structure by ground work. While adding steel plate blocks,
By repeating the operation of pushing down the steel plate block with the jack of the press-fitting device fixed to the columnar structure, the entire length of the columnar structure can be reinforced while the multiple steel plate blocks are continuously pressed into the ground. Since it is not necessary to form a work space by excavating the pillar structure buried in the ground widely and deeply, the cost required for reinforcing the pillar structure can be reduced, and the work period can be significantly reduced. effective.

[Brief description of the drawings]

FIG. 1A is a longitudinal sectional front view showing a construction state of reinforcement at a pier as one embodiment of the present invention, and FIG.
It is (A)-(A) sectional drawing in (A).

2A is an explanatory cross-sectional view of (B)-(B) of FIG. 1A, FIG. 2B is an enlarged cross-sectional explanatory view of a portion (C) in FIG. 2A, and FIG. It is an expanded sectional explanatory view of the modification of (c) part in Drawing 2 (A).

FIG. 3 is a front view of the press-fitting device.

FIG. 4 is a side view of FIG. 3;

FIG. 5 is a cross-sectional plan view showing a state where the press-fitting device is mounted on a pier.

FIG. 6 is a cross-sectional plan view of a press-fitting device having a chuck fastening structure different from that of FIG.

FIGS. 7A and 7B are perspective views of a standard steel plate block connected to a tip steel plate block and an upper part thereof, and FIG. 7C is a cross-sectional plan view of the steel plate block when covering the concrete pier.

FIG. 8 is a perspective view of another example of the steel plate block.

FIG. 9 is a perspective view of still another example of the steel plate block.

FIGS. 10A and 10B are first and second construction process diagrams of the present invention.

FIGS. 11A and 11B are third and fourth construction process diagrams of the present invention.

FIGS. 12A and 12B are fifth and sixth construction process diagrams of the present invention.

FIGS. 13A and 13B are seventh and eighth construction process diagrams of the present invention.

14A and 14B are ninth and tenth construction process drawings of the present invention, and FIG. 14C is a detailed view of part (d) of FIG.

FIGS. 15 (A) and (B) show eleventh and twelfth embodiments of the present invention.
FIG.

16 (A) and (B) show the thirteenth and fourteenth embodiments of the present invention.
(C) is a detailed view of part (e) of FIG. (A).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Floor slab 2 Bridge girder 3 Bridge pier 4 Press-in device 5 Steel plate block 6 Upper chuck 7 Lower chuck 8 Depression 10 Press-in jack 11 Division frame 12 Connection shaft 13 Bracket 14 Jack for chuck 15 Connection pin 16 Connection pin 17 Operation rod 18 Connection pin 19 Split Steel Plate Member 20 Bolt Insertion Hole 21 Vertical Joint Flange 22 Connecting Bolt 23 Taper Guide 24 Welding 25 Abrasive 26 Weld 27 Pressing Plate 28 Friction Cutter 29 Welding 30 Upper Horizontal Joint Flange 31 Bolt Insertion Hole 32 Lower Horizontal Joint Flange 33 Welding 34 Hoist 35 Hoist beam 36 Wire 37 Chute 38 Width stopper 39 Gap 40 Injection lot 41 Sealing process 42 Mortar 43 Non-shrink mortar 45 Injection pipe 46 Hanger 47 Earth and sand 48 Opening

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Amano 1-14 Kanda Iwamotocho, Chiyoda-ku, Tokyo Shiroishinai Co., Ltd. (72) Inventor Kenji Noguchi 2-1880 Nisshincho, Omiya City, Saitama Prefecture Shiraishi Kiko Co., Ltd. (72) Inventor Kunitaka Niwa 3-18 Kanda Nishiki-cho, Chiyoda-ku, Tokyo Showcase Construction Co., Ltd. (72) Inventor Hiroshi Yokoyama 3-18 Kanda Nishiki-cho, Chiyoda-ku, Tokyo F-term (Showa ) 2D059 AA01 AA03 GG40 GG55 2E176 AA04 AA13 BB03 BB15

Claims (6)

[Claims] In a reinforcing method for covering the outer surface of a columnar structure with a steel plate block, the divided steel plate block is applied to the outer surface of the columnar structure, and the steel plate block is assembled by joining joints of respective members. In addition, the steel plate block is pushed down by the press-fitting jack of the press-fitting device fixed to the upper part of the columnar structure to enter the ground, and a plurality of the steel plate blocks are assembled by repeating the pressing-down operation and the assembly of the steel plate block. Coating the outer surface of the columnar structure with the method. 2. A cylinder and an operating rod of the press-in jack are respectively connected to an upper chuck for a press-in reaction force and a lower chuck for urging a pressing force detachable from the columnar structure. By the timing operation of fixing and opening the upper chuck and the lower chuck,
The method for reinforcing a columnar structure according to claim 1, wherein the plurality of steel plate blocks are pressed down by causing the press-fitting device to perform a repetitive operation of vertical movement along the columnar structure. 3. The method for reinforcing a columnar structure according to claim 1, wherein the connecting means between the upper and lower steel plate blocks is a bolt or welding. 4. The steel plate block provided at the lowermost end has a cutting edge at a lower portion, and an abrasive for brushing the outer periphery of the columnar structure is provided inside the cutting edge. The method for reinforcing a columnar structure according to any one of claims 1 to 3. 5. A lower portion of a tip steel plate block provided at a lowermost end is opened between the columnar structure, and earth and sand which originally enter a gap between the columnar structure and the steel plate block through the opening, and originally. The method according to any one of claims 1 to 3, wherein the soil and sand existing around the columnar structure and remaining even after the steel plate block is pushed down are washed and discharged with high-pressure jet water injected from above the gap. The method for reinforcing a columnar structure according to the above. 6. A high-pressure jet water is injected into a gap formed between the outer surface of the columnar structure and the steel plate block to stir the slime existing in the gap, and then discharge the slime. The method for reinforcing a columnar structure according to claim 1, wherein mortar is injected into the gap.