Reinforcing steel plate and soil removing method

Abstract

To provide a reinforcing steel plate and a soil removing method capable of holding an interval against pressure in press-fitting and efficiently removing soil by air lift by limiting the range of the air lift.SOLUTION: In a reinforcing steel plate 1 installed around an existing columnar concrete structure (PC well 11) for repair or reinforcement, a plurality of interval holding materials (spacer guides 3, 3') for holding an interval with the existing columnar concrete structure (PC well 11) projects from an inner surface, and a partition plate 4 for partitioning a clearance G with the existing columnar concrete structure (PC well 11) in a specific range is installed on the inner surface on the side of a part of the plurality of interval holding materials (spacer guides 3, 3').SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a reinforcing steel plate that is installed around an existing columnar concrete structure for repair or reinforcement, and a method for removing soil around an existing columnar concrete structure using the same. [Background technology]

[0002] Conventionally, reinforcement methods for existing columnar structures such as bridge piers and their foundations have involved first installing a temporary cofferdam around the existing structure to create a dry area, then excavating soil and wrapping reinforcement materials around it using RC lining or steel plate lining methods. However, there was a problem in that temporary construction work, such as installing temporary cofferdams that are not directly related to the reinforcement work, took time and money.

[0003] Therefore, the reinforcing steel plate press-in method was developed to reinforce existing columnar structures such as existing bridge piers and foundations by pressing reinforcing steel plates into the ground. Compared to the conventional RC lining method and steel plate lining method, which involve installing a temporary cofferdam and then excavating, this reinforcing steel plate press-in method is easier to work with and more economical, and has become the mainstream reinforcement method for columnar RC structures in recent years.

[0004] One known method for removing soil from within the reinforcing steel plates used in this reinforcing steel plate press-in method is the air lift method, which involves blowing compressed air or gas into water mixed with soil and sand inside a steel pipe to make the apparent specific gravity of the air-bubble mixture inside the pipe lower than that of the liquid outside, thereby generating a relative lift force to remove the soil.However, simply applying the air lift method has the problem of poor soil removal efficiency and poor workability, as the diameter of the soil removal pipe is limited in the narrow gap between the reinforcing steel plates and structures such as bridge piers.

[0005] For example, Patent Document 1 discloses an earth removal device that uses the air lift effect from an annular space around the outer periphery of a columnar structure, and that includes a water supply means for maintaining the water level in the annular space at a predetermined level, a removable partition member that divides the annular space at predetermined intervals while allowing communication at the lower part thereof and forms a discharge flow path extending vertically, a fluid supply pipe that sprays air or a mixture of air and water downward toward the bottom of the discharge flow path, and a high-pressure air supply pipe that sprays high-pressure air horizontally or obliquely upward at a position above the lowest end of the partition member, within the discharge flow path (see claim 1 in the scope of claims of Patent Document 1, paragraphs

[0011] to

[0021] of the specification, Figures 2 and 3 of the drawings, etc.).

[0006] However, although the soil removal device using the air lift effect described in Patent Document 1 has improved soil removal efficiency, it has the problem of drawing in soil and sand from outside the reinforcing steel plate from the bottom end of the reinforcing steel plate after pressing in has been completed, making the workability of the final stage of soil removal excavation poor.

[0007] In order to solve these problems, the applicant of the present application proposed in Patent Document 2 a soil removal method for an earth removal device that removes soil from the gap between a reinforcing steel plate and an existing columnar structure when the reinforcing steel plate is pressed into the existing structure, the method comprising: a cylindrical earth removal jig body with open upper and lower ends; an injection port for injecting compressed gas formed in the side plates of the earth removal jig body; suction notches that are open in the vertical direction for sucking soil and sand formed in the front plate of the earth removal jig body that faces the existing structure; and an earth removal jig that has a linear lower end that is lower than the upper end of the suction notch and does not form a notch in the rear plate on the opposite side, the method using which soil and sand at the bottom of the reinforcing steel plate on the side of the existing structure is sucked through the suction notch and removed (see claim 1 of Patent Document 2, paragraphs

[0024] to

[0040] of the specification, Figures 2 to 4 of the drawings, etc.).

[0008] The soil removal jig and soil removal method described in Patent Document 2 solved the problem of soil being drawn in from outside the reinforcing steel plates, and provided good workability in the final stage of soil removal work, enabling soil to be neatly removed from corners and the bottom of the reinforcing steel plates. However, in the soil removal jig and soil removal method described in Patent Document 2, although stiffeners St are provided on the reinforcing steel plates to be pressed in, these are merely stiffeners, and in order to efficiently remove soil using the air lift effect, a soil removal jig that limits the range of the air lift was required.

[0009] On the other hand, Patent Document 3 discloses a method for installing earthquake-resistant reinforcing steel plates for columnar structures, in which reinforcing steel plates with spacing materials as spacers are pressed into columnar structures such as bridge piers to remove obstacles by pressing the reinforcing steel plates into underground structures, ensure the accuracy of steel plate installation, and simplify soil excavation.

[0010] However, although the reinforcing steel plate described in Patent Document 3 is provided with spacing materials (spacing retaining materials) that maintain the spacing against the pressure during pressing, the spacing materials are spacers for maintaining the spacing and cannot limit the area, and no consideration was given at all to limiting the range of the air lift and efficiently removing soil by using the air lift effect. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-328385 [Patent Document 2] Patent No. 6915186 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-74293 Summary of the Invention [Problem to be solved by the invention]

[0012] Therefore, the present invention has been devised in consideration of the above-mentioned problems, and its object is to provide a reinforcing steel plate and an earth removal method that can maintain the gap against the pressure during press-fitting, and that can efficiently remove earth by air lift by limiting the range of air lift. [Means for solving the problem]

[0013] The reinforcing steel plate of the first invention is a reinforcing steel plate that is installed around an existing columnar concrete structure for repair or reinforcement, and is characterized in that it has a plurality of spacing retaining members protruding from the inner surface to maintain a distance from the existing columnar concrete structure, and partition plates attached to the inner surface next to some of the spacing retaining members to divide the gap between the existing columnar concrete structure and the plate into a certain range.

[0014] The reinforcing steel plate according to a second aspect of the present invention is characterized in that, in the first aspect, the protruding length from the inner surface of the partition plate is set shorter than the protruding length of the spacing member.

[0015] The reinforcing steel plate according to the third invention is characterized in that, in the first or second invention, a jet guide is provided to pressure-feed compressed air or water jets of an airlift used for soil removal near the ground.

[0016] The earth removal method according to the fourth invention is a method for removing soil and sand from the clearance between a reinforcing steel plate installed around an existing columnar concrete structure and the existing columnar concrete structure, characterized in that the soil is removed using the pressure of compressed air from an air lift or a water jet while the gap between the existing columnar concrete structure and the reinforcing steel plate is divided into a certain range by a partition plate attached to the reinforcing steel plate.

[0017] According to the first to fourth inventions, the spacing material can maintain the spacing against the pressure applied when the reinforcing steel plate is pressed in, and the partition plate can divide the gap between the columnar concrete structure and the reinforcing steel plate into a certain range, thereby limiting the range of the pressure of the water jet or air lift and allowing the soil and sand in the clearance to be efficiently removed.

[0018] In particular, according to the second aspect of the present invention, the protruding length of the partition plate from the inner surface is set to be shorter than the protruding length of the spacer, so there is little risk of the partition plate being damaged during press-fitting.

[0019] In particular, according to the third aspect of the invention, a jet guide is provided, which can loosen clods of soil on any ground, allowing for efficient soil removal. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a plan view showing a state in which a reinforcing steel plate according to an embodiment of the present invention is installed around a PC well (a columnar concrete structure). [Figure 2] FIG. 2 is an enlarged view of part A in FIG. [Figure 3] FIG. 2 is an enlarged view of part B in FIG. [Figure 4] FIG. 4(a) is a development view of the reinforcing steel plate of the lowest row (first lot) as seen from the inside, and FIG. 4(b) is a side view thereof. [Figure 5] FIG. 5(a) is a development view of the reinforcing steel plate of the general portion as seen from the inside, and FIG. 5(b) is a side view thereof. [Figure 6] FIG. 6(a) is a development view of the uppermost reinforcing steel plate as seen from the inside, and FIG. 6(b) is a side view thereof. [Figure 7] FIG. 7 is a perspective view showing an outline of a construction method for installing reinforcing steel plates using the PC well-reflection method. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of a reinforcing steel plate and an earth removal method using the same according to the present invention will be described in detail with reference to the drawings.

[0022] [Reinforced steel plate] First, a reinforcing steel plate 1 according to an embodiment of the present invention will be described with reference to Figs. 1 to 6. A case will be described in which the reinforcing steel plate 1 is installed around a PC well 11 of a PC well pier by the PC well Refresh Method, which will be described later. Fig. 1 is a plan view showing the reinforcing steel plate 1 according to an embodiment of the present invention installed around a PC well 11. Fig. 2 is an enlarged view of part A in Fig. 1, and Fig. 3 is an enlarged view of part B in Fig. 1. Fig. 4(a) is a development view of the reinforcing steel plate 1' of the lowest level (first lot) as seen from the inside, and Fig. 4(b) is a side view thereof. Fig. 5(a) is a development view of the reinforcing steel plate 1 of the general section as seen from the inside, and Fig. 5(b) is a side view thereof. Fig. 6(a) is a development view of the reinforcing steel plate 1'' of the top level as seen from the inside, and Fig. 6(b) is a side view thereof.

[0023] (Steel plate body) 1 to 6, in the case of installation around a PC well 11 with a radius of 1500 mm, the reinforcing steel plate 1 according to this embodiment is a steel plate having a base steel plate body 10 formed into a cylindrical shape with a radius of 1650 mm (inner diameter of 3300 mm) from a rectangular steel plate with a thickness of about 12 mm to 16 mm and a width W1 = 3485 mm x height H1 = 1500 mm (1498 mm for the bottommost stage) when unfolded. Of course, each dimension is merely an example, and in this embodiment, when height adjustment is performed for two sheets, the topmost lot and the one below it, the height H1 of each lot is set to about 1000 mm.

[0024] (stiffener) 2 and other figures, stiffeners 2, made of 9 mm thick x 65 mm wide strip steel plate joined in the shape of a rectangular frame with a width W2 = 3285 mm x height H2 = 1300 mm, are temporarily welded to the outside of the steel plate body 10 so that they can be removed on site to maintain rigidity during transportation. Although not shown, flat bars 6 mm thick x 50 mm wide are attached along the horizontal and vertical edges of the steel plate body 10 as backing metal during welding.

[0025] (Spacer guide) As shown in Figures 1 and 2, a plurality of spacer guides 3 made of steel with a thickness T1 of 30 mm are protruded from the inner surface of the reinforcing steel plate 1 at predetermined intervals (in the illustrated form, the horizontal interval W3 is 872 mm, and the vertical interval H3 is 650 mm) as spacing retaining members to maintain the distance (clearance) from the PC well 11.

[0026] As shown in Figures 4(a) and 4(b), the spacer guide 3 for the bottommost reinforcing steel plate 1' in the first lot is a wedge-shaped spacer guide 3' with a pointed bottom end due to the need to press it into the ground, and as shown in Figures 5(a), 5(b), 6(a) and 6(b), the spacer guide 3 for the general reinforcing steel plates 1 in the second and higher tiers and the topmost reinforcing steel plate 1" from the second lot onwards is a semicircular spacer guide 3. In addition, the designed gap G between the PC well 11 and the steel plate body 10 is set to 150 mm, and the protruding length L1 of the spacer guide 3 from the inner surface of the steel plate body 10 is set to 140 mm.

[0027] (Partition plate) 1, 2, and 4 to 6, partition plates 4 made of strip steel plate with a thickness T2 of 6 mm or 9 mm and a protruding width L2 of 135 mm are attached to the sides of some of the spacer guides 3. These partition plates 4 have the function of limiting the range of air lift by dividing the gap between the PC well 11 and the steel plate body 10 into a certain range.

[0028] In the reinforcing steel plate 1 according to this embodiment, as described above, the projection length L1 of the spacer guide 3 from the inner peripheral surface of the steel plate body 10 is set to 140 mm, and the projection width L2 of the partition plate 4 installed beside it is set to L2 = 135 mm, which is shorter than the projection length of the spacer guide 3. Therefore, no pressure is input to the partition plate 4 when the reinforcing steel plate 1 is pressed in, and there is no risk of damage during press-fitting, even for steel plates with a thickness T2 = 6 mm or 9 mm.

[0029] (Jet Guide) 1 and 3, in the illustrated embodiment, 24 jet guides 5 are attached at regular intervals to the inner peripheral surface of the steel plate body 10. The jet guides 5 are composed of guide pipes 50 that send compressed air or water jets to the bottom of the lowest reinforcing steel plate 1' and steel rods 51 that serve as spacers for fixing the guide pipes 50 at a distance from the inner peripheral surface of the steel plate body 10, and have the function of loosening soil lumps in any ground so that they can be removed by connecting an air pipe or the like to the top edge of the top reinforcing steel plate 1 with a catch clamp or the like. For this reason, the attachment positions of the jet guides 5 are not limited to the illustrated embodiment and can be installed at any position depending on the conditions of the ground at the site, etc.

[0030] [Method of installing reinforcing steel plates and soil removal method] Next, a method for installing the reinforcing steel plate 1 and a soil removal method according to an embodiment of the present invention will be described with reference to FIG. 7. FIG. 7 is a perspective view showing an outline of a method for installing the reinforcing steel plate 1 using the PC well-refresh method. As shown in FIG. 7, the method for installing the reinforcing steel plate according to this embodiment is performed using the PC well-refresh method. A press-fit frame 13 is suspended from the head of a PC well pier B1, which is an existing columnar concrete structure. A press-fit ring 12 is bolted to the press-fit frame 13. A plurality of press-fit jacks 14 are attached to the press-fit frame 13. While the press-fit jacks 14 are used to obtain reaction force with ground anchors 15, the reinforcing steel plate 1 is wrapped around the PC well 11 and pressed into the ground G1. The reinforcing steel plate 1 is then integrated with the PC well pier B1 using a filler such as underwater non-segregating non-shrink mortar, thereby improving seismic performance.

[0031] (Press-fitting device installation process) First, in the method for installing reinforcing steel plates according to this embodiment, a press-in device installation process is carried out in which a press-in frame 13 is suspended and supported on the leg head of the PC well pier B1, and a press-in ring 12 and a plurality of press-in jacks 14 are attached to the press-in frame 13. In this process, a ground anchor 15 is installed in the ground G1 so that the reaction force generated when the press-in jack 14 is pressed in can be absorbed from the ground G1.

[0032] (First lot assembly process) Next, in the method for installing reinforcing steel plates according to this embodiment, a first lot assembly process is performed to assemble the first lot of the reinforcing steel plates. Specifically, in this process, the plurality of reinforcing steel plates 1' that form the bottom layer are welded together to form a cylindrical shape around the PC well 11.

[0033] (Reinforcing steel plate press-fitting process) Next, in the method for installing reinforcing steel plates according to this embodiment, a reinforcing steel plate press-in step is carried out in which a first lot of cylindrically assembled reinforcing steel plates is press-in inserted into the ground G1 using a press-in jack 14.

[0034] At this time, as mentioned above, the spacer guide 3 is attached to the reinforcing steel plate 1, so that the reinforcing steel plate 1 can be pressed vertically into the ground G1 while maintaining a constant clearance between the PC well 11 and the reinforcing steel plate 1.

[0035] Furthermore, as mentioned above, the protruding width L2 of the partition plate 4 provided beside the spacer guide 3 is set to 135 mm, which is slightly shorter than the protruding length L1 of the spacer guide 3, which is 140 mm (see Figure 2). Therefore, no pressure is input to the partition plate 4 when it is pressed in, and there is no risk of it being damaged during the press-fitting process.

[0036] (Next lot assembly process) Next, in the method for installing reinforcing steel plates according to this embodiment, a next lot assembly process is carried out in which multiple reinforcing steel plates 1 are welded together to assemble the next lot of reinforcing steel plates 1, such as the second lot, into a cylindrical shape around the PC well 11.

[0037] (Reinforcing steel plate press-fitting process) Next, a reinforcing steel plate press-in process is carried out in which the cylindrically assembled lot of reinforcing steel plates 1 is pressed into the ground G1 using a press-in jack 14. At this time, depending on the hardness and condition of the ground G1, a water jet or air lift is used in combination to partially remove soil from the top of the ground G1 while pressing the reinforcing steel plates.

[0038] Thereafter, the next lot assembly process and the reinforcing steel plate press-fitting process are repeated to form a reinforcing steel plate assembly of a predetermined height (predetermined step).

[0039] (Clearance cleaning process) After that, a clearance cleaning process is performed in which the clearance between the PC well 11 and the reinforcing steel plate 1 is cleaned with a water jet or the like. Specifically, a water jet or compressed air is pumped in, and the soil and sand in the clearance are removed as muddy water from the top end of the reinforcing steel plate 1 by an air lift. This process is continued until the rising muddy water becomes clean water, thereby cleaning the clearance between the PC well 11 and the reinforcing steel plate 1.

[0040] At this time, as mentioned above, a partition plate 4 made of a strip steel plate is attached to the reinforcing steel plate 1, and this partition plate 4 can divide the gap between the PC well 11 and the steel plate main body 10 into a certain range, thereby limiting the range of the water jet and air lift pressure and allowing the soil and sand in the clearance to be efficiently removed.

[0041] (Filling material filling process) Next, in the method for installing reinforcing steel plates according to this embodiment, a filler filling process is carried out in which a filler such as underwater non-segregating non-shrinkage mortar is filled into the clearance between the PC well 11 cleaned in the clearance cleaning process and the reinforcing steel plate 1.

[0042] Thereafter, the filler filled in the filler filling step hardens, and the installed reinforcing steel plate 1 and the PC well pier B1 are integrated, thereby completing the method for constructing a reinforcing steel plate according to this embodiment.

[0043] However, if reinforcement is required for the upper part of the PC well 11 where the press-fitting devices such as the press-fit ring 12, press-fitting stand 13 and press-fitting jack 14 are installed, the upper part is also wrapped with reinforcing steel plates and the necessary anti-corrosion coating is applied.

[0044] The reinforcing steel plate 1 according to the embodiment of the present invention and the soil removal method using it described above can maintain the spacing against the pressure applied when the spacer guide 3, which is a spacing-retaining material, is pressed in, and since a partition plate 4 made of a strip steel plate is attached to the inside of the reinforcing steel plate 1, the gap between the PC well 11 and the steel plate main body 10 can be divided into a certain range, and the range affected by the pressure of the water jet or air lift can be limited, allowing the soil and sand in the clearance to be removed efficiently.

[0045] Furthermore, in the reinforcing steel plate 1 and the soil removal method using it according to this embodiment, the protruding width L2 of the partition plate 4 provided beside the spacer guide 3 is set to a protruding width L2 = 135 mm, which is slightly shorter than the protruding length L1 = 140 mm of the spacer guide 3, so that no pressure is input to the partition plate 4 when the reinforcing steel plate 1 is pressed in, and there is no risk of damage during pressing.

[0046] The reinforcing steel plate 1 according to the embodiment of the present invention and the soil removal method using the same have been described in detail above. However, the above-described and illustrated embodiments are merely specific embodiments for carrying out the present invention. Therefore, the technical scope of the present invention should not be interpreted as being limited by these embodiments. [Explanation of symbols]

[0047] 1,1',1”: Reinforced steel plate 10: Reinforced steel body 2: Stiffener 3,3': Spacer guide (spacing material) 4: Partition board 5: Jet Guide 50: Guide tube 51: Steel rod G: Gap (clearance) 11: PC well (columnar concrete structure) 12: Press-fit ring 13: Press-fit stand 14: Press-fit jack 15: Ground anchor P1: PC well pier G1: Ground

Claims

1. A reinforcing steel plate installed around an existing columnar concrete structure for repair or reinforcement, A plurality of spacing retaining members are protruding from the inner surface to maintain a distance from the existing columnar concrete structure, A partition plate is attached to the inner surface of some of the spacing retainers to separate the gap between the existing columnar concrete structure and the spacing retainers to a certain range. A reinforced steel plate characterized by:

2. The protruding length from the inner surface of the partition plate is set to be shorter than the protruding length of the spacing member. The reinforcing steel plate according to claim 1,

3. A jet guide is provided to send compressed air and water jets from the airlift used for soil removal near the ground. The reinforcing steel plate according to claim 1 or 2, characterized in that

4. A method for removing soil and sand from a clearance between a reinforcing steel plate installed around an existing columnar concrete structure and the existing columnar concrete structure, comprising: The gap between the existing columnar concrete structure and the reinforcing steel plate is divided into a certain range by a partition plate attached to the reinforcing steel plate, and the soil is removed using the pressure of compressed air from an airlift or water jet. A soil removal method characterized by the above.

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