JP5872724B1 - Construction method of underwater temporary closing structure - Google Patents

Abstract

[PROBLEMS] To attach a high-pressure water injection nozzle to the lower end side of a liner plate that is press-fitted into the underwater ground, thereby facilitating the press-fitting while blowing off the underwater ground, thereby vibrating the liner plate with a manually operated impacting device. By making it possible to press-fit while giving it, it is intended to provide technology that allows all manual construction of a dry work space. When a temporary cutoff structure is driven into an underwater ground, high-pressure water is ejected from a number of ejection ports, whereby the earth and sand of the underwater ground can be blown away or softened. If it is the underwater ground in such a state, the liner plate can easily enter the underwater ground by its own weight only by giving a slight vibration by an impactor (air hammer) that can be installed manually. Formation of a dry work space is easy without requiring a large construction machine or the like. [Selection] Figure 1

Description

In the present invention, in the case of investigating underwater structures such as bridge piers and caissons, repairing / seismic reinforcement work, etc., the minimum necessary earth retaining work is performed by manual work using liner plates etc. which are commercially available products, The present invention relates to a construction method for an underwater temporary closing structure capable of omitting large construction machines, shortening the construction period, drastically reducing the amount of earth and sand to be excavated, and drastically reducing costs.

  Recently, earthquake-proof reinforcement work has been applied to all structures in preparation for a huge earthquake. For example, seismic reinforcement work for underwater bridge piers involves reinforced concrete winding, steel plate winding, carbon fiber and aramid fiber winding, etc., all of which are dry (dry). In the work space).

The most orthodox construction method for forming a dry work space is to first attach a clamshell or backhoe to the crane of the work ship to excavate and remove the underwater ground in the water. The foundation structure (footing) is exposed. Thereafter, the periphery of the pier on the footing is surrounded by a liner plate, and water in the liner plate is removed to form a dry work space. And while constructing a scaffold in this dry work space, seismic reinforcement work such as winding of the reinforced concrete, winding of a steel plate, winding of carbon fiber or aramid fiber is performed.

However, in this method, when excavating and removing the underwater ground, a large amount of underwater ground must be excluded over a wide area, the construction period becomes longer, and the removed sediment is temporarily stored. There was a disadvantage that the number of trolleys to keep increased. In addition, after the seismic reinforcement work has been completed, it is necessary to back up the removed earth and sand, and the amount of earth and sand to be backed up becomes enormous, further increasing the overall construction period and causing a significant increase in costs. It was. Furthermore, in order to eliminate excavation of the underwater ground, it was necessary to prepare a work ship equipped with a crane, and a large facility was required. This large-sized facility has resulted in further cost increase.

As one method for solving such a problem, there is a technique disclosed in Patent Document 1. In the technique shown in Patent Document 1, floor digging is performed until the upper surface of the footing of the pier is exposed by a backhoe carrier or the like, and a temporary cutoff structure is constructed on the upper surface of the footing. The temporary cut-off structure is constructed by drilling the upper surface of the footing exposed by floor digging and implanting anchor muscles. A plurality of reinforcing rings made of H-shaped steel or the like are assembled in an annular shape around the pier, and the whole is suspended and fixed to the anchor muscles planted on the footing by underwater welding or the like.

Next, the first stage of the cut-off body is installed on the upper surface of the reinforcing ring, and an outer formwork is installed on the upper surface of the annularly formed reinforcing ring outer peripheral side by stacking sandbags. And the outer peripheral side of the outer mold is backfilled with the underwater ground excavated and removed. Thereafter, underwater concrete is placed on the upper surface of the footing inside the outer mold such as a sandbag, and the gap between the lower end of the first stage cut-off body and the upper surface of the footing is sealed with the underwater concrete. . Next, the second-stage and subsequent cut-off bodies are sequentially assembled above the first-stage cut-off body and assembled so as to surround the pier, thereby forming a temporary cut-off structure.

 Finally, the internal water enclosed by the deadline is drained to build a dry working space inside the deadline. In this dry work space, investigation, repair, reinforcement work, etc. of underwater existing structures such as piers will be performed.

Moreover, there exists a technique shown in patent document 2 as another conventional temporary closing structure. In the temporary closing structure of Patent Document 2, the reinforcing ring body is press-fitted from the top end of the water bottom ground to a position deeper than the upper end of the footing portion such as a bridge pier. The reinforcing ring body surrounds the outer periphery of the footing part. Since the reinforcing ring body is press-fitted to a predetermined depth below the upper end of the footing portion with the top end of the water bottom ground as the press-fitting start point, it is press-fitted in a plurality of stages in the depth direction. The lowermost reinforcing ring body has a press-fitting blade at the lower end.

As a press-fitting reaction force means for press-fitting the reinforcing ring body into the water bottom ground, a ground anchor installed in the water bottom ground, a ring body fixed to a bridge pier, or the like is used. The press-fitting of the reinforcing ring body into the water bottom ground is performed by installing a press-fitting girder on the reinforcing ring body, installing a press-fitting jack on the press-fitting girder, and connecting the press-fitting jack and a ground anchor as a means of press-fitting reaction force. Yes.

Next, a plurality of ring-shaped liner plates are installed so as to extend from the upper end of the reinforcing ring body to the surface of the water. After the outer periphery of the bridge pier is surrounded by a temporary cut-off structure composed of a reinforcing ring body and a ring-shaped liner plate, excavation is performed from the top of the water bottom ground to the top of the footing part. Since excavation is performed in a space surrounded by a temporary cut-off structure, rivers and the like are not polluted, and dredging and excavation amount can be reduced.
Finally, water-stopping concrete or the like is placed between the reinforcing ring body and the upper end of the footing part, and the work space surrounded by the temporary cut-off structure composed of the reinforcing ring body and the ring-shaped liner plate is stopped. It draws water and forms a dry work space. In this dry work space, investigation, repair, reinforcement work, etc., such as piers are performed in the same manner as in the case of Patent Document 1.

JP 2009-019449 A JP 2005-264500 A

  However, the technique described in Patent Document 1 has a problem that the number of steps for constructing a temporary closing structure for forming a dry work space is increased, and the construction period is still prolonged. The construction process for the provisional deadline structure consists of a floor digging process that exposes the footing with a clamshell or backhoe of a trolley, a process of implanting anchor bars on the footing, and an annular assembly of the reinforcement ring around the pier. Welding the anchor bars, installing a temporary fastening body on the reinforcing ring, stacking a sandbag on the outer peripheral side of the reinforcing ring body, installing the outer formwork, Furthermore, the process of backfilling the outer peripheral side, the process of placing underwater concrete between the reinforcing ring and the footing to stop water, the process of adding a cut-off body to the surface of the water, and the inside space of the cut-off body At least nine steps with the process of draining were required.

  In addition, after investigating piers, repairing and reinforcing work, etc. in a dry work space, the temporary fastening structure must be removed, but the temporary fastening body can be removed by simply removing the bolt connection, but the reinforcing ring Is underwater concrete and integrated with the footing, so large-scale removal work such as fusing the reinforcement ring around the pier, etc. by welding, cutting the underwater concrete and cutting the reinforcement ring from the anchor bar, etc. It was necessary and the construction period was prolonged.

In the technique described in Patent Document 2, a press-fitting girder is installed above a reinforcing ring body formed in a ring around a bridge pier, and a hydraulic jack is further installed on the press-fitting girder. The reinforcement ring body is pressed into the underwater ground. In order to press-fit the reinforcing ring body, it is necessary to construct a press-fit reaction force means for the hydraulic jack. The press-fitting reaction force means that a ground anchor is installed in the water bottom ground or a ring body is fixed to the upper outer peripheral surface of the pier, but in any case, a reinforcing ring body formed in an annular shape on the outer peripheral side of the footing is used. It must be able to withstand considerable press-fitting reaction force because it is pressed into the underwater ground with a hydraulic jack.

When performing a press-fitting reaction force that can withstand such a large force by installing a ground anchor in the water bottom ground, a large concrete block body must be buried to a considerable depth, and the formation and delivery of the concrete block body, Excavation of submerged ground, installation of concrete block body, backfilling, connection of ground anchor and hydraulic jack, connection work after press-fitting and removal of press-fitting girder are necessary, and the preparatory process before construction of temporary cut-off body was large. It was.
Also, even when a ring body as a press-fitting reaction force means is constructed on the upper outer peripheral surface of the pier, it is necessary to attach a large steel frame to the pier, and there is a similar problem.

Furthermore, press-fitting of the reinforcing ring body is done by fixing the supporting columns at several locations inside the reinforcing ring body, and connecting the upper ends of these supporting columns to the horizontal press-fitting girder that forms a framework by crossing the outer periphery of the pier. However, the press-fitting girder is pressed down with a hydraulic jack, and it involves complicated work such as attaching the support column to the reinforcing ring body, installing the press-fitting girder, and disassembling the work. It was one of the factors that extended the period.

  Therefore, the present invention has been improved and removed in view of the above-mentioned conventional problems, and by attaching a high-pressure water injection nozzle to the lower end side of the liner plate that is press-fitted into the underwater ground, By making it easy to press-fit while blowing away, and by making it possible to press-fit while applying vibration to the liner plate with a striker that can be done manually, we will provide a technology that can build a dry work space all by hand It is.

The means of claim 1 adopted by the present invention in order to solve the above problems comprises a curved shape or a straight planar shape obtained by dividing the entire shape surrounding the underwater existing structure into a plurality of pieces, and a lower end surface. Is connected to the lowermost provisional deadline liner plate, which has a nozzle body equipped with a number of jets of high-pressure water, in a ring shape, and a commercially available temporary deadline is attached to the upper end surface of the lowermost provisional deadline liner plate. An arbitrary number of stages are connected to the liner plate through H-shaped steel, and an impactor or vibrator that can be manually installed is attached to several upper end surfaces of a commercially available temporary fastening liner plate that is located on the uppermost stage exposed from the water surface. High pressure water is jetted from a number of high pressure water jets provided on the nozzle body to blow or soften sedimentary sediment on the underwater ground, and in that state, it is connected in a ring shape while applying vibration with the impactor or vibrator. Driving the entire temporary shut-off liner plate in a plurality of stages into water in the ground, while the provisional deadline liner plate of the uppermost is not sink to the water surface, once removed the striking device or shaker, for provisional deadline through the H-shaped steel A liner plate is added, and an impactor or a vibrator is attached to the upper end of the further added liner plate, and high-pressure water is sprayed from the high-pressure water injection port to blow or soften sedimentary sediment on the underwater ground. The entire multiple stages of temporary fastening liner plates connected in a ring shape while being vibrated by an impactor or vibrator are driven into the underwater ground, and these operations are repeated to drive the temporary fastening liner plate to the desired depth. after performing these tasks under the environment in water, the interior of the sediment of the provisional deadline liner plate in a plurality of stages of the ejector system A method for constructing an underwater temporary closing structure characterized in that it is discharged using a jet pump to form a dry work space around an existing underwater structure, and all work is performed manually. It is.

The lowermost provisional cutoff liner plate used in the invention of claim 1 is provided with a nozzle body provided with a number of high-pressure water injection ports on the lower end surface. When press-fitting into the underwater ground, high-pressure water is sprayed from a large number of injection ports, so that the earth and sand of the underwater ground can be blown away or softened. In the case of the underwater ground in such a state, the liner plate can easily enter the underwater ground by its own weight only by giving a slight vibration by an impactor (air hammer) that can be installed manually.

In the first aspect of the present invention, the lowermost liner plate is disposed in a ring shape around the existing underwater structure, and a commercially available liner plate is attached to the upper end surface thereof. What is necessary is just to determine the installation step number of the commercially available liner plate after the 2nd step | paragraph according to the water depth and the soil quality of the underwater ground. Further, impacting devices such as an air hammer are attached to a plurality of locations on the upper end surface of the uppermost liner plate. These liner plates are pressed into the underwater ground by injecting high-pressure water from the bottom liner plate injection port to blow away the soil on the ground, or by softening and applying vibration with the uppermost impact device. . That is, after making the underwater ground side soft, vibration is applied by a hitting device, and the weight of these liner plates is used to press-fit into the underwater ground.

Further, in the first aspect of the present invention , after the temporary closing structure is constructed through the above-described steps, the underwater ground inside the temporary closing structure is discharged and drained to form a dry working space. The discharge of the underwater ground inside the temporary closing structure can be carried out manually by the worker by using the technique using the applicant's jet pump to form a dry working space. Is possible. In addition, the construction process of the temporary deadline structure is extremely small, and the construction period can be shortened and the construction cost can be greatly reduced.

It is a half section front view around a bridge pier showing the state just before driving the temporary closing structure concerning one embodiment of the present invention into underwater ground. FIG. 2 is a plan view of the state of FIG. 1 according to an embodiment of the present invention. It is a vertical side view of a temporary closing structure according to an embodiment of the present invention. It is a perspective view which shows the nozzle body which concerns on one Embodiment of this invention. It is a half section front view around a bridge pier showing the state where the temporary deadline structure concerning one embodiment of the present invention was driven into the underwater ground. It is a half section front view around the pier showing the state where the inside of the temporary closing structure concerning one embodiment of the present invention was made into the dry work space.

  Hereinafter, the liner plate for temporary closing of this invention, the temporary closing structure, and the construction method are demonstrated with reference to drawings. FIG. 1 is a half sectional front view around a bridge pier showing a state immediately before the temporary closing structure 1 is driven into the underwater ground 2, FIG. 2 is a plan view thereof, and FIG. 3 is a longitudinal side view showing the temporary closing structure 1. FIG. 3 is a perspective view of the nozzle body 3. As shown in FIG. 3, the temporary cutoff structure 1 is formed using a commercially available liner plate 4. The commercially available liner plate 4 is provided with flanges 5 having connecting bolt holes on the four circumferential side surfaces thereof, and is formed in a corrugated plate shape when it is sectioned to increase the strength. The commercially available liner plate 4 is manufactured in various shapes and sizes, and each of the liner plates 4 is divided into a circular shape, a track shape, and a rectangular shape when connected and assembled. It is arcuate or straight. In the embodiment shown in the drawings, the whole is configured to have a track shape when viewed in plan.

Thus, the nozzle body 3 shown in FIG. 4 is connected and fixed to the lower end surface flange 5 of the lowermost liner plate 4 using bolts 6 and nuts (not shown). The inside of the nozzle body 3 functions as an accumulator chamber 7 for high-pressure water, and is configured so that high-pressure water can be ejected simultaneously from a plurality of nozzles 8 (see FIG. 3).
A second-stage liner plate 4 is connected to the upper end surface side of the lowermost liner plate 4 via an H-shaped steel 9 via bolts and nuts.

Further, the lowermost liner plate 4 and the central portion of the liner plate 4 connected to the uppermost stage via an H-shaped steel 8 on the uppermost portion penetrate the vertical direction and communicate with the accumulator chamber 7 of the lowermost nozzle body 3. A high pressure water hose 11 is provided. The connection between the nozzle body 3 and the high-pressure water hose 11 can be performed by a one-touch type using a coupler 12 or the like, and the work at the site is easy. The high-pressure water hose 11 may be connected by a coupler for each stage of the liner plate 4, or may be continuous within a range not interfering with an impactor (air hammer) or a vibrator 15 described later. Good.

Furthermore, a slipping plate 10 is attached to at least the outer surface (the left side surface in FIG. 3) or the inner and outer surfaces of these liner plates 4 and 4 by welding. As a result, the nozzle body 3, the liner plate 4 and the H-shaped steel 9 are flush with each other, and a great reduction in resistance when driven into the underwater ground is obtained. The liner 10 does not necessarily have to be attached to both the inside and outside surfaces, and may be either one side. In the case of mounting on one side, the outer side is preferred (FIG. 3 shows the case where only the outer side is provided). This is because the liner 10 can maintain the water-stopping property when attached to the outer side surface. Moreover, it is because it is more convenient to have opened the inner side surface for fastening bolts and nuts for connecting the liner plates 4 to each other. When the liner 10 is attached to the inner side surface, it is necessary to perform after the fastening operation of these liner plates 4 and the above-described connection operation of the couplers 12 of the high-pressure water hose 11 are completed.

As shown in FIG. 1, when the two-stage liner plates 4 and 4 are connected and fixed, the water depth shown in the drawing is that the lower end is on the underwater ground 2 and the upper end protrudes onto the water surface. The liner plates 4 and 4 are connected and fixed in a track shape so as to surround the periphery of the footing 14 of the pier 13. And the striker or the vibrator 15 is arrange | positioned at predetermined intervals on the upper end surface of the liner plate 4 exposed from the water surface.

Next, the temporary closing structure 1 composed of the two-stage liner plate 4 connected in a track shape so as to surround the periphery of the footing 14 is driven into the underwater ground 2. In the construction procedure, first, high-pressure water is supplied from a high-pressure pump (jet pump) mounted on a carriage to the nozzle body 3 attached to the lower end surface of the lowermost liner plate 4 via a high-pressure water hose 11. Thereby, high-pressure water is jetted as a jet jet from the nozzles 8 attached to the plurality of jet ports of the nozzle body 3. This jet of high-pressure water blows or softens the sediment on the ground underwater.
In this state, when an impactor (air hammer) or a vibrator 15 attached to the upper end surface of the uppermost liner plate 4 is driven, the vibration is transmitted to the entire temporary fastening structure 1 connected and fixed in a track shape. Then, the entire temporary closing structure 1 sinks into the underwater ground 2 that has been blown away with high-pressure water or softened by its own weight alone.
At this time, when the slipping plate 10 is installed only on the outer side surface, if the softened ground is discharged using an ejector-type jet pump or the like on the inner side surface, the resistance when driven by the H-shaped steel 9 It can be reduced.

When the water sinks into the ground to some extent, the impactor or vibrator 15 installed on the upper end surface of the uppermost liner plate 4 is once removed, and the liner plate 4 is further connected to the liner plate 4 via the H-shaped steel 9. And add. FIG. 5 shows a case where a two-stage liner plate 4 is newly added to make a total of four stages. In this case, considering the soil quality and water depth of the underwater ground 2, how much depth to sink into the underwater ground 2 is set, or how much the size in the water is to jump out from the surface of the water What is necessary is just to determine the installation stage number of the liner plate 4 according to necessity. This is because if the soil quality of the underwater ground 2 is soft, there is a risk that water will ooze inside the temporary closing structure 1 unless it is driven deeply. This is because if the upper end surface of the uppermost liner plate 4 does not protrude above the water surface, water will flow down from the upper end of the liner plate 4 and a dry working space cannot be formed.

In the embodiment shown in FIG. 5, the high-pressure water hose 11 is led out from the third-stage liner plate 4, and is disposed through the inside of the third-stage and fourth-stage liner plates 4. There is no need to do. Thereby, it is possible to reduce the burden of the field worker underwater.

In this way, the middle part of the second stage is driven into the underwater ground 2, and when the upper end surface of the uppermost four-stage liner plate 4 jumps out of the water surface, the temporary closing structure 1 is placed. finish. The high-pressure water hose 11 may be removed from the middle of the high-pressure water hose 11 and carried to the outside of the temporary cutoff structure 1, and the striker 15 installed on the upper end surface of the uppermost liner plate 4 may be removed.

After that, as shown in FIG. 6, the water enclosed by the temporary closing structure 1 is drained by a pump, and the accumulated sediment on the underwater ground inside the temporary closing structure 1 is discharged. The earth and sand can be discharged using a clamshell, a backhoe, an ejector-type jet pump, or the like. The present applicant is good at eliminating underwater ground using an ejector-type jet pump.

The ejector-type jet pump is provided with a high-pressure water supply pipe that injects driving high-pressure water toward the downstream side in the curved portion of the pipe line that is turned in a right-angle direction, and a throttle is provided in the middle to supply high-pressure water. An air suction pipe is provided so as to face the throttle, and air is sucked by a negative pressure generated by jet jet water, and bubbles are mixed and transported. Since it is a system in which air bubbles are mixed evenly from the beginning, cavitation does not occur and clogging does not occur. By jetting high-pressure water, negative pressure is generated on the inlet side of the pipe, and gravel such as sand, gravel, and pebbles can be transported. Gravels that can be transported can be up to 90% of the pump diameter (diameter of the pipe line), and with a diameter of 12 cm, pebbles as large as about 10.8 cm can be transported. It is. FIG. 6 shows a state in which the underwater ground in the region surrounded by the temporary closing structure 1 is removed up to the height of the upper end surface of the footing 14.

In addition, if the underwater ground 2 between the outer peripheral surface of the footing 14 and the inner peripheral surface of the temporary cutoff structure 1 is made lower than the height of the upper end surface of the footing 14, the water that has flowed out of the underwater ground 2 will enter this portion. Since it accumulates, it is easy to pump with a drain pump, and even if there is some spring water, it is always possible to ensure a dry working space.

  As shown in FIG. 6, after the underwater ground 2 is discharged and drained until the upper end surface of the footing 14 is exposed, a scaffold is placed around the pier 13 in this dry work space. Assembling, dry pier 13 investigation, repair, earthquake-proof reinforcement work, etc.

  Thus, according to the present invention, the dead weight of the temporary closing structure 1 is utilized by blowing and softening the underwater ground 2 by jetting high-pressure water, and by the vibration of the impactor or the vibrator 15 on the upper end surface of the liner plate. Thus, the temporary deadline structure 1 is driven into the underwater ground 2 around the footing 14 so as to form a dry work space inside the temporary deadline structure 1. The number of trolleys for temporary storage can be reduced, the construction period can be shortened, the cost can be greatly reduced, and large equipment can be eliminated. In addition, a large construction machine or the like is not required to form a dry work space, all work can be done manually, and the cost reduction effect is enormous.

  Although the above description demonstrated the earth retaining method in the case of performing an earthquake-proof reinforcement work with respect to the pier in water, this invention is not limited to this, It is attached to the lower end surface of the lowermost liner plate 4 The nozzle body 3 may be configured by arranging the nozzles attached to the tip of one high-pressure water hose 11 at predetermined intervals. Further, the operation of driving the liner plate 4 into the underwater ground 2 may be performed in the middle using the impactor or the vibrator 15 in the middle, and the uppermost liner plate 4 is moved upward from the water in the final stage. What is necessary is just to make it protrude.

DESCRIPTION OF SYMBOLS 1 ... Temporary deadline structure 2 ... Underwater ground 3 ... Nozzle body 4 ... Liner plate 5 ... Liner plate flange 7 ... Accumulator chamber 8 ... Nozzle 9 ... H-shaped steel 10 ... Liner 11 ... High pressure water hose 12 ... Coupler 13 ... Pier 14 ... Footing 15 ... Batter (air hammer) or vibrator

Claims (1)

The entire shape surrounding the existing underwater structure is divided into a plurality of curved shapes and straight planar shapes, and a nozzle body equipped with a number of high-pressure water jets is attached to the lower end surface. A lower temporary liner plate is connected in a ring shape, and a commercial temporary fastener liner plate is connected to the upper end surface of the lower temporary liner plate via H-shaped steel and exposed from the water surface. The impactor or vibrator that can be installed manually is installed at several locations on the upper end surface of a commercially available temporary fastening liner plate located at the uppermost stage, and high pressure water is jetted from a number of high pressure water injection ports provided in the nozzle body. Blow off or soften the sediment on the ground, and in that state, strike the entire multi-stage temporary fastening liner plate connected in a ring shape to the underwater ground while applying vibration with the impactor or vibrator. Seen, while the provisional deadline liner plate of the uppermost is not sink to the water surface, once removed the striking device or vibration device, via the H-shaped steel replenishing the provisional deadline liner plate, again further topped upper end of the liner plate A blower or vibrator is attached and high-pressure water is jetted from the high-pressure water jet to blow off or soften sedimentary soil on the underwater ground, and in that state, it is connected in a ring shape while applying vibration with the striker or vibrator. After driving the entire multi-stage temporary deadline liner plate into the underwater ground, repeating these operations to the desired depth for the temporary deadline liner plate , performing these operations in an underwater environment, The sediment deposited inside the temporary deadline liner plate is discharged using an ejector-type jet pump, and is then dripped around the existing underwater structure. So as to form a Do work space, the construction method of the provisional deadline structures in water, characterized in that all the work was carried out in operation by human power.

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