JP5390044B1 - Underwater earth retaining method - Google Patents

Abstract

An underwater earth retaining method that does not require a large facility such as a work boat equipped with a crane, and that only eliminates a minimum amount of sedimentary sediment, and can shorten the construction period and reduce costs. I will provide a.
A frame forming member such as H-shaped steel is disposed on a boundary line of a region where sedimentary sediment in water is to be excavated and removed, and a guide member for a retaining member such as T-shaped steel or H-shaped steel is provided on the inner surface side of the frame forming member. Installed at a predetermined interval in the vertical direction, insert the earth retaining member between the guide members, drive the earth retaining member into the sediment by applying vibration with a pile driver from the upper end side of the earth retaining member, The earth was fixed to the outside of the area where earth and sand would be excavated.
[Selection] Figure 4

Description

  The present invention provides a minimum amount of earth retaining work using commercially available liner plates, etc., in the case of applying seismic reinforcement work to underwater structures such as bridge piers and caissons, etc. It is related with the earth retaining method in the water which can implement | achieve the drastic reduction of the quantity of water, and the drastic reduction of cost.

  Recently, earthquake-proof reinforcement work has been applied to all structures in preparation for a huge earthquake. For example, reinforced concrete winding, steel plate winding, carbon fiber and aramid fiber winding, etc. are carried out on the pier part under the seismic reinforcement work on the pier part underwater. Is called. Therefore, as the most orthodox construction method, first, as shown in FIG. 6, the underground soil structure (footing) 2 buried in the underground G of the pier 1 is exposed by excavating and removing the sediment F underwater. I am letting. The excavation and removal of sedimentary sediment is performed by preparing a work ship equipped with a crane (not shown) and attaching a clamshell or backhoe to the crane.

Thereafter, the reinforced concrete is constructed while surrounding the bridge pier 1 on the footing 2 with a liner plate by using a construction method of the temporary closing structure described in Patent Document 3 to eliminate water in the liner plate and constructing a scaffold. Seismic reinforcement work, such as winding up, was done dry. In addition, in FIG. 6, the code | symbol 3 is a foundation pile and 4 is a bridge girder.

  Conventionally, there are other seismic reinforcement works as shown in Patent Documents 1 and 2. In the seismic reinforcement work shown in Patent Document 1, first, a retaining wall made of steel sheet piles is cast and formed around the footing to a predetermined depth, and then the inner earth and sand surrounded by the retaining wall is excavated and removed. In general, a steel sheet pile is placed by preparing a work ship equipped with a crane and suspending a steel sheet pile placing machine with the crane. Then, after placing the steel sheet pile, as in the case shown in FIG. 6, a dry environment is formed by the construction method of the temporary closing structure described in Patent Document 3, and the predetermined seismic reinforcement work is performed. Is going.

  In the seismic reinforcement work shown in Patent Document 2, a work boat is used to provide an underwater earth retaining wall for steel sheet piles. The earth retaining wall is made by attaching a sheet pile driving machine to a crane mounted on a work boat. When the underwater retaining wall is provided, a clamshell or a backhoe is attached to the crane of the work boat, and the outer periphery of the footing and the sediment on the upper side of the footing are excavated and removed. Then, on the upper side of the footing, a dry environment is formed by the construction method of the temporary closing structure described in Patent Document 3, and the predetermined seismic reinforcement work is performed.

Japanese Patent Laid-Open No. 11-323988 JP 2003-232044 A Japanese Patent No. 4625532

However, in the case shown in FIG. 6, since earth retaining work is not performed with a steel sheet pile or the like, the accumulated earth and sand F around the footing 2 must be excavated over a wide range, and the accumulated earth and sand are excavated. There was a drawback that the amount to be removed became enormous, the construction period was prolonged, and the number of trolleys for temporarily storing the removed sediment was 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, the excavation and removal of sedimentary earth and sand required the preparation of a work ship equipped with a crane, and a large facility was required. This large-sized facility has resulted in further cost increase.

  On the other hand, in the seismic reinforcement work described in Patent Document 1 and Patent Document 2, it is necessary to prepare a work ship equipped with a crane and to install a retaining wall forming member such as a steel sheet pile, which requires a large facility. In addition, there is a drawback that the cost of the steel sheet pile is increased.

Furthermore, in the cases shown in Patent Documents 1 and 2, it is necessary to prepare a work ship equipped with a crane, but there is a shallow place where such a large facility machine cannot be carried in and the presence of surrounding structures. Therefore, in an environment where a crane cannot be used, such a construction method may not be employed. Therefore, it is impossible to drive steel sheet piles or the like with the large equipment, and it was necessary for an underwater worker to dig up a wide range of accumulated sediment as shown in FIG. After removing the sediment, it is necessary to form a dry environment in the footing 2 after soiling by sandbags, etc., and to perform seismic reinforcement work on it. And the heavy burden on underwater workers.

  Therefore, the present invention is obtained by improving and removing the above in view of the above-mentioned conventional problems, and connecting a H-shaped steel or the like to an arbitrary region and arranging a frame forming member, and a T-shaped steel or It is intended to provide an underwater earth retaining method in which H-shaped steel or the like is attached, a retaining wall forming member is inserted between them, and an operator places the retaining wall forming member in water.

  The means of claim 1 adopted by the present invention in order to solve the above-mentioned problem is in the case of excavating and removing sediments around the underwater structure in order to perform seismic reinforcement work on the underwater structure such as a harbor or a river. A frame forming member such as H-shaped steel is arranged on the boundary line of the region where sediment sediment in the water is desired to be excavated, and a guide member of a retaining member such as T-shaped steel or H-shaped steel is vertically arranged on the inner surface side of the frame forming member. Installed at predetermined intervals, insert a retaining member between the guide members, and excavate the retaining member into the sediment by applying vibration from the top end of the retaining member with a pile driver. This is an underwater earth retaining method characterized in that earth retaining is performed on the outside of an area to be excluded.

  According to the second aspect of the present invention, the earth retaining member is driven into the sediment, and then the sediment in the region surrounded by the earth retaining member is excavated and removed, and the position of the earth retaining member at an arbitrary depth is determined. Then, an L-shaped or U-shaped bracket member is welded and fixed to the retaining member, and a reinforcing member such as H-shaped steel or prismatic steel is fitted and mounted between the bracket and the retaining member. The soil retaining method in water according to claim 1, wherein the intermediate portion is reinforced.

  The means of Claim 3 which this invention employ | adopted is the earth retaining method in the water of Claim 1 or 2 which attached the wire to the frame formation member, connected with the float on the water surface, and has arrange | positioned the frame member in water.

  According to a fourth aspect of the present invention, the frame member is suspended in water by suspending the frame forming member from a construction on water or a trolley via a crane or the like. The earth retaining method.

  The means of Claim 5 which this invention employ | adopted is the earth retaining method in the water of Claim 1 or 2 which has arrange | positioned the frame member in water by attaching the leg which reaches a water bottom under the frame formation member.

According to the invention of claim 1, the frame forming member is formed around the pier, for example, using commercially available H-shaped steel or the like. On the inner surface side, guide members of earth retaining members such as H-shaped steel or T-shaped steel are attached in the vertical direction at predetermined intervals. Then, the earth retaining member is inserted between the guide members, and the earth retaining member is driven into the sediment by applying vibration with a pile driver from the upper end side of the earth retaining member. ing.
If this is the case, a large facility such as a work boat equipped with a crane is not required at all, and it is only necessary to prepare a small pile driver that is manually operated by an operator. Moreover, since the earth retaining can be performed in the minimum necessary area, the amount of earth and sand to be excavated is reduced, and the construction period can be shortened and the cost can be reduced.

  According to the second aspect of the present invention, when the depth of the earth retaining member is increased, after the earth retaining member is implanted, the accumulated sediment in the enclosed region is excavated and removed at an arbitrary depth position. A bracket such as an L-shaped angle or a U-shaped angle is fixed to the member by welding at predetermined intervals. Then, reinforcing members such as H-shaped steel and prismatic steel are bridged over these brackets to reinforce the intermediate portion of the earth retaining member.

  According to the invention of Claims 3 to 5, the frame forming member of the invention of Claim 1 is arranged and fixed at an arbitrary position in water. In Claim 3, it is hung with the float, Claim 4 is hung with the crane, In Claim 5, the leg is attached.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the earth retaining method concerning one Embodiment of this invention, and shows the whole in the case of earth retaining around a bridge pier. The earth retaining method concerning one Embodiment of this invention is shown, and it is a partially expanded perspective view which shows the state which inserted the earth retaining member in the frame formation member. BRIEF DESCRIPTION OF THE DRAWINGS It is the longitudinal cross-sectional view which shows the earth retaining method concerning one Embodiment of this invention, and shows the driving | running state to the ground of the earth retaining member. BRIEF DESCRIPTION OF THE DRAWINGS It is the longitudinal cross-sectional view which shows the earth retaining method concerning one Embodiment of this invention, and shows the state which driven the earth retaining member around the footing of the bridge pier. BRIEF DESCRIPTION OF THE DRAWINGS It is the perspective view which shows the earth retaining method concerning one Embodiment of this invention, and shows the attachment state of the reinforcement member arrange | positioned in the middle of the earth retaining member. It is a longitudinal cross-sectional view which shows the circumference | surroundings of the bridge pier in the case of excavating and removing the conventional sedimentary sediment.

  Hereinafter, the present invention will be described based on an embodiment in the case where earth retaining work is performed as a pre-process of seismic reinforcement work performed on a bridge pier in water. First, as shown in FIG. 1, the frame forming member 5 is arranged at an arbitrary height position in water around the pier 1. The area surrounded by the frame forming member 5 can be a minimum area where the sediment around the pier 1 is desired to be excavated. Specifically, it may be set near the periphery of the footing 2. In the case of this embodiment, the case where the frame forming member 5 is formed of H-shaped steel is illustrated. As shown in FIG. 2, the H-shaped steel may be connected to each other with bolts 7 and nuts after the end faces of the H-shaped steels are butted against each other. Further, as shown in FIGS. 3 and 4, the H-shaped steel frame forming member 5 is attached to the intermediate connecting portion 5A of the frame forming member 5 with a hook bolt 8 and connected to the float 10 via the wire 9. It is suspended and placed at a predetermined height in the water.

  As shown in FIGS. 2 and 3, the guide member 12 of the earth retaining member 11 is welded and fixed to the inner surface side of the frame forming member 5 in the vertical direction. Specifically, Y-shaped steel, T-shaped steel, H-shaped steel, or the like is applicable as the guide member 12, and the drawing shows the case of H-shaped steel. The guide member 12 is attached to the inner surface side of the frame forming member 5 at predetermined intervals, and a length of about several tens of cm to 1 m is sufficient. As the earth retaining member 11, the liner plate described in Patent Document 3 can be used in the vertical direction. For example, a wave-shaped liner plate having a width of 500 mm and a length of 1500 mm, which is a commercial product, is used. Can do. As shown in FIG. 2, the liner plate serving as the earth retaining member 11 includes vertical frames 11A and 11B on the left and right ends, and a corrugated plate portion 11C that connects these vertical frames.

  The earth retaining member 11 may be driven by an operator who has submerged in water by installing a manual air pile driver (not shown) on the upper end side of the earth retaining member 11 and driving it. As shown in FIG. 4, the driving depth may be slightly deeper than the upper end surface of the footing 2. In this way, after the earth retaining member 11 is driven in the immediate vicinity of the footing 2 along the frame forming member 5 around the pier 1, a clamshell, a backhoe, or an ejector type jet pump is used. The accumulated sediment in the area surrounded by the earth retaining member 11 is excluded. At work sites where clamshells or backhoes can be used, sedimentary sediment can be excavated.

  In a work site under an environment where a large facility such as a clamshell or a backhoe cannot be used, an underwater worker can remove sediment by 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. In order to enable jet injection, an air suction pipe is provided facing the throttle, and air is sucked by a negative pressure of jet spray 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, a 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. 4 shows a state in which the accumulated earth and sand in the region surrounded by the frame forming member 5 is removed up to the height of the upper end surface of the footing 2.

  By the way, when the accumulated earth and sand are accumulated to a considerable height from the upper end surface of the footing 2, as shown in FIG. Then, the earth retaining member 11 may be added by fastening with a nut. In the drawing, the case where the flat plate 13 and the bolts 14 and nuts are connected on the front and rear end face sides of the left and right end frames 11A and 11B is shown, but the left and right side faces may be connected. You may make it connect in the part (refer FIG. 2) of the corrugated plate part 11C with a board. If there is such a large amount of accumulated sediment, the intermediate portion of the retaining member 11 may not be sufficient for earth pressure. In that case, as shown in FIG. 5, after removing accumulated sediment in a region surrounded by the retaining member 11 to a certain depth, an L-shaped angle or a U-shape is formed at an arbitrary intermediate portion of the retaining member 11. The bracket 14 such as an angle is fixed by welding. Then, a reinforcing member 15 such as H-shaped steel or prismatic steel is fitted and mounted across the brackets 14 so as to reinforce the earth pressure at the intermediate portion.

  After the removal of the sediment in the region surrounded by the frame forming member 5 is performed until the upper end surface of the footing 2 is exposed as shown in FIG. The temporary closing structure may be constructed on the footing 2 around the pier 1, the water in the temporary closing structure is removed, and the pier 1 is subjected to seismic reinforcement work in a dry manner.

  As described above, according to the present invention, the earth retaining member 11 is driven into a necessary minimum region and the accumulated sediment on the inner surface side thereof is excavated and removed. 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. Moreover, when the removed earth and sand are backfilled, the construction can be easily performed, and the construction period can be further shortened and the cost can be reduced.

  The above explanation has explained the earth retaining method in the case of applying seismic reinforcement work to underwater bridge piers, but the present invention is not limited to this, for example, dry-type seismic reinforcement work for caisson etc. It can also be applied to repair work. In addition, it can also be used as a soil retaining method when performing some kind of construction on all underwater structures such as repair of steel pipe piles and quay walls. In addition, as a method of disposing the frame forming member 5 in the water, the case of suspending from the float 10 has been described. However, the frame forming member 5 may be suspended from a work ship or a crane disposed on the ground, and a leg is attached to the frame forming member 5. You may make it support to the seabed and the bottom of the water.

DESCRIPTION OF SYMBOLS 1 ... Bridge pier 2 ... Footing 5 ... Frame formation member 8 ... Hook bolt 9 ... Wire 10 ... Float 11 ... Earth retaining member 12 ... Guide member 14 ... Bracket 15 ... Reinforcement member

Claims (5)

  When excavating and removing sediments around the underwater structure in order to perform seismic reinforcement work on underwater structures such as harbors and rivers, a frame of H-shaped steel or the like is placed on the boundary line of the area where the sediment in the water is to be excavated. A forming member is arranged, a guide member of a retaining member such as T-shaped steel or H-shaped steel is attached to the inner surface side of the frame forming member at predetermined intervals in the vertical direction, and the retaining member is inserted between the guide members. The underwater is characterized in that the earth retaining member is driven into the sediment by applying vibration with a pile driver from the upper end side of the earth retaining member, and the earth retaining is performed outside the area where the earth and sand are to be excavated. Earth retaining method.   After the earth retaining member is driven into the sediment, the accumulated earth and sand in the region surrounded by the earth retaining member is excavated and removed, and the L retaining member is formed into an L shape or a U shape at an arbitrary depth position of the earth retaining member. The bracket member is fixed by welding, and a reinforcing member such as H-shaped steel or prismatic steel is fitted and mounted between the bracket and the retaining member to reinforce the intermediate portion of the retaining member. The earth retaining method in water described in 1.   The underwater submerged construction method according to claim 1 or 2, wherein a wire is attached to the frame forming member and connected to a float on the water surface to dispose the frame member in water.   The underwater earth retaining method according to claim 1 or 2, wherein the frame forming member is suspended from a structure on water or a trolley via a crane or the like to dispose the frame member in water. The underwater submergence method according to claim 1 or 2, wherein the frame member is disposed in water by attaching a leg that reaches the bottom of the water below the frame forming member.

Images