JP2018053660A - Cutting edge structure, method for verifying damage of cutting edge and method for repairing cutting edge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting edge structure, a method for verifying damage of a cutting edge and a method for repairing a cutting edge, which secure workability of drilling operation, and with which a repair work is easily carried out.SOLUTION: A cutting edge structure that is provided annularly along an outer periphery of the lower end of a caisson skeleton 10 comprises a concrete-made cutting edge main body 21 integrally provided in a bottom slab 12 of the caisson skeleton 10 and protruding downward from the outer peripheral edge of the bottom slab 12, and a cutting edge steel plate 22 covering at least a tip portion of the cutting edge main body 21 through the whole circumference. In the cutting edge steel plate 22, a through hole 22a that penetrates in a thickness direction is formed, communicating with the through hole 22a at the inner peripheral side of the cutting edge steel plate 22, and a valve 25 for opening/closing the through hole 22a is provided.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a blade edge structure, a blade edge damage confirmation method, and a blade edge repair method.

Conventionally, the caisson frame used for the pneumatic caisson method is provided integrally with the bottom plate of the caisson frame, and is provided in a ring shape along the outer periphery of the bottom plate and protrudes downward from the outer periphery of the bottom plate. A blade edge structure is provided. As a blade edge structure, as shown, for example, in Patent Document 1, a blade edge fitting attached to the lower edge of the blade edge body is provided.
In such a pneumatic caisson method, the cutting edge is sunk by excavating the ground in a pressure environment higher than the pressure outside the caisson housing by pressurizing the working chamber defined between the bottom plate and the ground. The caisson enclosures are laid down in sequence.

  When the caisson housing is laid down, the cutting edge provided at the lower end of the caisson housing is a part that enters the ground under the load of the caisson housing, and further has a tapered shape with the thickness gradually decreasing toward the lower edge. Is formed. For this reason, the blade edge is easily damaged. In various standards, etc., the blade edge shoulder width is widened, the distance between the blade edge rebars is narrowed, and the blade edge hardware is installed at the tip edge of the tapered blade edge. It is recommended that the concrete of the blade edge be made strong.

Japanese Patent Application Laid-Open No. 09-242083

However, in the conventional case, when the caisson skeleton is set on the ground such as hard ground or cobblestone and sand and gravel, the blade edge is often locally subjected to a large load due to the collapse of the ground or sudden settlement. In such a case, even if the blade edge fitting is attached to the tip edge portion of the blade edge structure, damage has occurred in each part of the concrete blade edge structure.
If the blade edge structure is damaged and expanded, for example, groundwater flows into the working chamber or the caisson housing is inclined, so that excavation work becomes difficult and repair is required. In such a case, work related to groundwater treatment and repair is performed in a small working chamber under high pressure, which requires time and effort, and there is room for improvement.

  The present invention has been made in view of the above-described problems, and provides a blade edge structure, a blade edge damage confirmation method, and a blade edge repair method capable of easily performing repair work while ensuring workability of excavation work. The purpose is to provide.

  In order to achieve the above object, the blade structure according to the present invention is a blade structure provided in an annular shape along the outer periphery of the lower end portion of the caisson housing, and is provided integrally with the bottom plate of the caisson housing, A concrete blade edge body projecting downward from the outer peripheral edge of the bottom plate, and a blade edge steel plate covering the entire circumference of at least the tip of the blade edge body, the blade edge steel plate having a thickness A through-hole penetrating in the direction is formed, and communicates with the through-hole on the inner peripheral side of the blade steel plate, and has an opening / closing operation part for opening and closing the through-hole.

  The blade edge repair method according to the present invention is a blade edge repair method in the above-described blade edge structure, wherein the opening / closing operation part is opened to enter and stay between the blade edge body and the blade edge steel plate. Draining the groundwater to the inner peripheral side through the through hole, and after draining the groundwater, grout from the work chamber below the bottom plate to the outer peripheral surface side of the blade steel plate through the through hole. And a step of injecting a material.

In the present invention, even when the concrete blade edge main body is damaged when the caisson housing is laid down, the inner peripheral surface side of the blade edge main body is covered with the blade edge steel plate. It is possible to suppress a large amount of groundwater from flowing into the lower working chamber. And when the blade edge main body is damaged in this way, by opening the opening / closing operation part communicating with the through hole formed in the blade edge steel plate, the blade edge body and the blade edge steel plate are connected through the through hole. The groundwater that has entered and stayed during the period can be drained to the working room side. Furthermore, after draining the groundwater, it is possible to perform repair work on the damaged portion of the blade edge body by injecting the grout material from the work chamber side to the outer peripheral side of the blade edge steel plate using the through hole.
And in the present invention, since it is possible to repair by injecting the grout material, it is not necessary to remove the blade steel plate from the blade body and perform the repair work, and the repair work can be performed very easily. Is possible.
Therefore, in the present invention, the repair work can be easily performed while ensuring the workability of the excavation work.

  The blade edge structure according to the present invention may be characterized in that the blade edge steel plate covers the entire inner peripheral surface of the blade edge body.

  According to such a blade edge structure, it is possible to more reliably prevent groundwater from flowing into the work chamber on the inner circumferential side by covering the entire blade blade body with the blade steel plate from the inner circumferential side.

  Further, the blade edge damage confirmation method according to the present invention is a blade edge damage confirmation method using the blade edge structure described above, and by opening the opening / closing operation unit that is normally closed, The blade edge main body is confirmed to be damaged by the state of groundwater flowing into the working chamber below the bottom plate.

  Further, in the present invention, by confirming the state of groundwater flowing into the working chamber from the through hole by visual inspection or the like by opening the opening / closing operation unit that is normally closed, it is confirmed whether or not the blade body is damaged. It is possible to detect damage to the blade edge main body at an early stage and perform the repair as described above.

  According to the blade edge structure, the blade edge damage confirmation method, and the blade edge repair method of the present invention, the repair work can be easily performed while ensuring the workability of the excavation work.

It is a schematic sectional drawing which shows the pneumatic caisson by embodiment of this invention. It is a partial expanded sectional view which shows a blade edge structure.

  Hereinafter, a blade edge structure, a blade edge damage confirmation method, and a blade edge repair method according to embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the caisson housing 10 of the present embodiment is a reinforced concrete tubular structure used when a structure such as a bridge pier constructed in water is constructed by a pneumatic caisson method. The lower end portion is placed in the ground G, and the annular body block is placed at the upper end of the side wall 11 while being submerged by its own weight, and then the lower end portion is sequentially disposed.

An annular blade structure 20 along the outer periphery is provided at the lower end of the caisson housing 10.
The blade edge structure 20 is formed in a tapered shape whose inner peripheral surface is expanded toward the lower end side. The caisson housing 10 is in a state in which the lower end edge 20a of the blade structure 20 is in pressure contact with the ground G. That is, a space surrounded by the blade structure 20 (hereinafter referred to as a work chamber 13) is provided below the bottom plate 12, and the pressure in the work chamber 13 is set higher than the soil water pressure outside the caisson housing 10. By maintaining a high level, the ground G below the lower edge 20a of the blade structure 20 can be maintained while maintaining the balance between the weight of the caisson housing 10 and the pressure of the working chamber 13 with respect to the ground G during construction. By excavating from the working chamber 13 side, the caisson housing 10 is sunk by its own weight.

  As described above, the space between the bottom slab 12 and the ground G on the inner peripheral side of the blade structure 20 serves as a work chamber 13 for performing excavation work. The inside of the working chamber 13 is pressurized with air pressure so as to resist the soil water pressure around the caisson housing 10. The working chamber 13 is provided with a material shaft 14 having a material lock 14a provided in a substantially vertical direction through the bottom plate 12, and a man shaft 15 having a manlock 15a.

  As shown in FIG. 2, the blade edge structure 20 is provided integrally with the bottom plate 12 of the caisson housing 10, and has a concrete blade edge body 21 projecting downward from the outer peripheral edge of the bottom plate 12, and the blade edge body. 21 and a steel cutting edge steel plate 22 that is divided into a plurality of pieces in the circumferential direction.

  The blade opening body 21 is formed integrally with the bottom plate 12 and protrudes in an annular shape downward. The blade edge main body 21 has a shape that is thinner than the side wall 11 and has a thickness that gradually decreases toward the lower end, and the distal end portion 21a is flat in the thickness direction.

  The blade edge steel plate 22 is arranged in a state in which a plurality of blade edge steel plates 22 divided in the circumferential direction are adjacent to the blade edge body 21 from the inner circumference side in the circumferential direction without a gap. The cutting edge steel plate 22 extends along the side plate portion 23 curved along the inner peripheral surface 21 b of the cutting edge main body 21, the bottom plate portion 24 along the flat surface of the tip end portion 21 a of the cutting edge main body 21, and the lower surface 12 a of the bottom plate 12. The top plate portion 26 is integrally joined. That is, since the blade steel plate 22 covers the entire inner peripheral surface 21b of the blade main body 21 and the lower surface 12a of the bottom plate 12, water stoppage can be ensured and water can be prevented from flowing into the working chamber 13. .

The side plate portion 23 is provided with a valve 25 (opening / closing operation portion) on the inner peripheral surface 23a of the side plate portion 23 in communication with a through hole 22a penetrating in the thickness direction. The through-holes 22a are disposed at intermediate positions in the vertical direction of the side plate portion 23, and are provided at intervals in a plurality of positions in the circumferential direction.
The valve 25 is provided so as to protrude from the blade steel plate 22 toward the inner peripheral side, and can be manually opened and closed by the operator in the work chamber 13.

Next, the operation of the blade edge structure, blade edge damage confirmation method, and blade edge repair method described above will be described in detail based on the drawings.
In the present embodiment, even when the concrete blade edge main body 21 is damaged when the caisson housing 10 is laid down, the inner peripheral surface 21b side of the blade edge main body 21 is covered with the blade edge steel plate 22, It is possible to prevent a large amount of groundwater from flowing into the working chamber 13 below the bottom slab 12 from the damaged portion of the concrete. In particular, by covering the entire blade edge main body 21 with the blade edge steel plate 22 from the inner peripheral side as in the present embodiment, it is possible to more reliably prevent groundwater from flowing into the working chamber 13 on the inner peripheral side. .

  And when the blade edge | tip main body 21 is damaged in this way, the valve | bulb 25 connected to the through-hole 22a formed in the side-plate part 23 of the blade-edge steel plate 22 is open | released, and a blade is cut | disconnected through the through-hole 22a. The groundwater that has entered and stayed between the mouth body 21 and the blade steel plate 22 can be drained to the working chamber 13 side.

Furthermore, after draining the groundwater, the grout material is injected into the outer peripheral side of the blade steel plate 22 from the work chamber 13 side using the through-hole 22a, so that the damaged portion of the blade blade body 21 can be repaired. It becomes possible. And in this Embodiment, since it is possible to repair by inject | pouring grout material, it is not necessary to remove the blade-steel steel plate 22 with respect to the blade-mouth main body 21, and to perform repair work, and repair work is very much. It can be done easily.
Therefore, in the present embodiment, the repair work can be easily performed while ensuring the workability of the excavation work.

Further, in the present embodiment, by opening the valve 25 that is normally closed, the state of the groundwater flowing into the working chamber 13 from the through hole 22a is confirmed by visual observation, etc. The presence or absence of damage can be confirmed, and damage to the blade edge main body 21 can be detected at an early stage to perform the repair as described above.
Specifically, whether or not the blade edge main body 21 is damaged can be confirmed based on whether or not groundwater flows out from the valve 25 (through hole 22a). In addition, since a plurality of valves 25 are arranged at intervals in the circumferential direction, the number of these valves 25 is opened as appropriate, and the position of damage to the blade body 21 is confirmed from the position of the valve 25 from which groundwater flows out. can do. Furthermore, it is also possible to confirm the degree of damage to the blade body 21 by the amount of groundwater flowing out from the valve 25.

  As described above, according to the blade edge structure, the blade edge damage confirmation method, and the blade edge repair method according to the present embodiment, when the blade edge structure 20 is damaged, the repair work can be easily performed. .

As mentioned above, although the embodiment of the blade edge structure, the blade edge damage confirmation method and the blade edge repair method according to the present invention has been described, the present invention is not limited to the above embodiment, and does not depart from the spirit thereof. It can be changed as appropriate.
For example, in the present embodiment, the valve 25 is used as the opening / closing operation unit, but the present invention is not limited to this. For example, a cap-type (screw-type) lid-like opening / closing operation unit may be used. In addition, without providing the valves 25 for all of the plurality of through holes 22a, the valves 25 are provided for some of the through holes 22a that are appropriately selected, and for other through holes 22a, an opening / closing operation such as a cap is performed. A portion may be provided.

  Further, the attachment positions of the through holes and the opening / closing operation section may be any positions as long as the blade steel plate 22 is used, and the number of arrangements, the arrangement interval, and the like can be appropriately set. For example, in the case where a portion that is easily damaged in the blade main body 21 can be predicted in advance, the through holes and the opening / closing operation unit may be intensively arranged at the portion.

  Further, in the present embodiment, each of the blade-edge steel plates 22 divided in the circumferential direction is configured to be mounted on the blade-edge main body 21 by a fixing jig, but is not limited thereto. For example, the structure which joined the blade-edge steel plates 22 which were divided | segmented integrally by welding may be sufficient.

  In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Caisson housing | casing 11 Side wall 12 Bottom plate 13 Work chamber 14 Material shaft 14a Material lock 15 Man shaft 15a Man lock 20 Blade edge structure 21 Blade edge body 21a Tip part 21b Inner peripheral surface 22 Blade edge steel plate 22a Through hole 23 Side plate part 23a Inside Peripheral surface 24 Bottom plate part 25 Valve (opening / closing operation part)
26 Top plate part G Ground

Claims (4)

A blade structure provided annularly along the outer periphery of the lower end of the caisson housing,
A concrete blade mouth body provided integrally with the bottom plate of the caisson housing and projecting downward from the outer peripheral edge of the bottom plate;
A blade steel plate that covers at least the tip of the blade body over the entire circumference; and
With
The blade steel plate is formed with a through-hole penetrating in the thickness direction,
A blade edge structure comprising an opening / closing operation part for opening and closing the through hole while communicating with the through hole on an inner peripheral side of the blade steel plate.   The blade edge structure according to claim 1, wherein the blade edge steel plate covers an entire inner peripheral surface of the blade edge main body. A blade edge damage confirmation method using the blade edge structure according to claim 1 or 2,
By opening the opening / closing operation section that is normally closed, the blade edge main body is confirmed to be damaged by the state of groundwater flowing into the working chamber below the bottom plate from the through hole. How to check the blade edge damage. A blade edge repair method in the blade edge structure according to claim 1 or 2,
Draining the groundwater that has entered and stayed between the blade body and the blade steel plate by opening the opening / closing operation part, and draining it to the inner peripheral side through the through hole;
After draining the groundwater, injecting a grout material from the work chamber below the bottom plate to the outer peripheral surface side of the blade steel plate through the through hole;
A blade edge repairing method characterized by comprising:

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