JP2011184923A - Rocking reducing apparatus in towing caisson - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance rocking stability in towing by a simple apparatus and to secure safety in towing at a low cost. <P>SOLUTION: This rocking reducing apparatus in towing a caisson includes: a pair of hanging members 3 provided along both side faces of the caisson 1 floating on the water surface so that the lower ends hang downward from the side face lower edge of the caisson 1; weights 4 suspended from the lower ends of the respective hanging members 3; and a movement regulating member 5 setting the turning center of a free hanging length part 3b, located on the lower side from the caisson 1, of each hanging member 3, to the side face lower edge of the caisson. The upper ends of both hanging members 3 are detachably connected to the upper part of the caisson 1. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a shake reduction device for caisson towing that reduces the shake caused by waves when towing to a place where a hollow caisson is levitated above the water surface.

  In general, caisson used for breakwaters, etc. is floated on the surface of the water in a hollow state, towed to the site using a dredger, and after reaching a predetermined point, by inserting padding material such as stone into the caisson or seawater injection It is allowed to settle and land on the bottom mound.

  Caisson surfaced on the surface of the water is inferior in stability to waves and winds compared to ships navigating in the open ocean. is there. Even in such a case, in many cases, the tow is carried out in a state where the center of gravity is moved downward by adding a ballast water or a method of thickening the bottom plate by placing ballast concrete in order to enhance stability.

  The long caisson has the advantage that the revetment and breakwater can be completed at an early stage, while its towing requires multiple dredging fleets to secure the stability of the sway and requires a lot of time and money.

  Conventionally, as a method of reducing the shaking at the time of towing of a floating structure such as a caisson, there is a method of fixing a plate-like member for reducing the shaking to the bottom bottom portion or the side portion of the floating structure (for example, Patent Documents). 1 and 2).

  In addition, the caisson is retracted and held between the catamarans of the catamaran to reduce swaying, navigate stably to the installation site, increase the weight by pouring water into the caisson at the installation site, etc. Method (for example, Patent Document 3), and the method of reducing the fluctuation during towing by holding between two buoyancy trolleys, towing to the installation site in this state, and hanging at the installation site (for example, Patent There is literature 4).

JP 2006-240341 A JP 2005-239157 A Japanese Patent Laid-Open No. 7-331667 JP 2003-3480 A

  Among the conventional methods for reducing shaking during towing, in the method of lowering the center of gravity of the caisson by placing ballast concrete or pouring water, the distance that can be lowered is restricted by the height of the caisson, and sufficient stability cannot be obtained. There's a problem.

  In addition, the method of fixing the plate-like member for reducing the vibration to the bottom and side of the bottom of the floating structure uses ancillary equipment that fixes to the floating body, so it is difficult to remove and attach to the caisson in advance. For this reason, there is a problem in terms of strength, such as cost reduction and cross-sectional defects in the floating structure.

  In addition, in the method of using the catamaran and the two buoyancy trolleys described above, it is necessary to separately procure a large dedicated ship, and depending on the ship standard, due to restrictions on balance with caisson dimensions. There is a problem that it may not be used.

  In view of such a conventional problem, the present invention can increase the stability of towing motion by a simple device regardless of the size and shape of the caisson, and enables caisson towing even under poor wave conditions. The purpose of the present invention is to provide a shake reduction device for caisson towing that can ensure safety during towing at low cost and can reduce the number of towing vessels required for towing.

  In order to solve the conventional problems as described above and achieve the intended purpose, the invention is characterized in that the lower end is below the lower side edge of the side of the caisson along both sides of the caisson floated on the water surface. A pair of suspension members suspended from the suspension member, a weight suspended from the lower ends of the suspension members, and a movement center of the free suspension long portion below the caisson of both suspension members as a caisson side lower edge. And a regulating member, wherein the upper ends of the suspension members are detachably connected to the upper part of the caisson.

  The invention according to claim 2 is characterized in that, in addition to the structure of claim 1, the movement restricting member is configured by a laterally-facing connecting member in which both ends are connected to each suspension member at the lower edge positions of both side surfaces of the caisson. It is in.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect of the present invention, the suspension members are supported by a front-rear direction movement restriction guide that is fixed at a lower side edge position of the caisson. The movement in the front-rear direction is restricted.

  In the vibration reduction device according to the present invention, the upper ends of a pair of suspension members whose lower ends are suspended below the lower side edge of the caisson are removably connected to the upper portions of the caissons, and weights are suspended from the lower ends. As a result, the movement distance of the center of gravity position when the sway reduction device is mounted can be adjusted by the length of the suspension member, and the center of gravity position can be lowered to a position where the behavior of the caisson is sufficiently stable.

  This increases the restoring force when shaken in the rolling direction, increases the stability against waves, enables caisson towing even under poor wave conditions, and reduces the number of dredgers required for towing, A low-cost and highly safe shake reduction effect can be obtained.

  In addition, when the caisson is inclined in the rolling direction, the caisson side surface is provided with a movement restricting member having the rotation center of the free hanging long part below the caisson of the both suspension members as the caisson side lower edge. The weight load acts on the lower edge portion downward, and the restoring force is greater.

  In the present invention, the movement restricting member is constituted by a laterally connecting member whose both ends are connected to each suspension member at the lower edge positions of both side surfaces of the caisson, so that the suspension member is fixed to the caisson only to the upper part of the caisson. When removing the caisson, the entire suspension is lifted by suspending one of the suspension members by means of a crane or the like and releasing the fixation to the other caisson, thereby facilitating the removal work.

  In the present invention, with the front and rear direction movement restriction guide fixed to the lower side edge position of the caisson, the both suspension members are restricted to move in the front and rear direction, so that during swinging or towing in the pitching direction Even when the suspension member is inclined in the pitching direction due to the resistance of water, the point of action of the downward load on the lower side edge of the caisson does not move, and the suspension member is stably held.

It is a front view of the state which mounted | wore the caisson with the fluctuation reduction apparatus which concerns on this invention. It is the same side view. FIG. 2 is a front view showing an upper body in which the caisson shown in FIG. 1 is inclined in the rolling direction.

  Next, embodiments of the present invention will be described based on examples shown in the drawings.

  FIG. 1 and FIG. 2 show a state in which the apparatus for reducing shaking during caisson towing according to the present invention is mounted on a caisson levitated on the surface of the water. In FIG.

  The sway reduction device 2 has a pair of suspensions in which the lower ends of the caisson 1 are suspended downward by a predetermined length from the upper side edges 1b and 1b of the caisson 1 along the side surfaces from the upper edges of the side surfaces 1a and 1a. It has materials 3 and 3 and weights 4 and 4 suspended under both suspension materials 3 and 3.

  Each suspension member 3 is composed of a caisson height length portion 3a having a length extending from the upper edge to the lower edge of the side surface 1a of the caisson 1, and a free drooping length portion 3b suspended below the lower caisson. Yes.

  The movements of the suspension members 3 and 3 are restricted by the movement restricting member that forms the center of rotation of the free hanging portion 3b below the caisson side lower edge portions 1b and 1b. In this embodiment, the movement restricting member is constituted by a laterally connecting member 5 along the bottom surface of the caisson 1 and having both ends connected to the suspension members 3 and 3 at the positions of the lower edges 1b and 1b of the caisson side surface.

  The suspension members 3 and 3 and the laterally connecting member 5 can be various bendable cords such as a rope material such as a wire rope, a chain, or a combination thereof.

  At the corner of the lower edge of the caisson side surface, the front and rear direction movement restriction guides (slipping stoppers) 6 and 6 for preventing wear by the suspension member 3 and restricting the movement of the suspension member in the front and rear direction are fixed.

  A plurality of the vibration reduction devices 2 configured as described above are installed along the length direction of the caisson 1 as shown in FIG. As a result, as shown in FIG. 1, the center of gravity G2 added to the caisson 1 and the shake reducing device 2 is positioned below the center of gravity G1 of the caisson 1 itself.

  By mounting the sway reduction device 2 in this way, the overall center of gravity position is lowered, so that the stability of the floating caisson 1 is improved, and the sway reduction device 2 after the sway reduction device 2 is mounted from the center of gravity G1 of the caisson 1 itself. Since the center of gravity G2 is at the bottom, a horizontal restoring force is applied when it is shaken in the rolling direction as shown in FIG.

  Therefore, the lengths of the free hanging portions 3b and 3b of the suspension members 3 and 3 are set so that the position of the center of gravity G2 that changes due to the mounting of the vibration reduction device 2 becomes more appropriate according to the size and shape of the caisson. And the weights 4 and 4 are adjusted. The weight 4 can be a concrete block formed to a required weight.

  Further, as shown in FIG. 3, both suspension members 3, 3 restrict the rotational axis positions of the free hanging long portions 3 b, 3 b to the lower edge of the caisson side surface by the connecting member 5 that is a movement restricting member. When rolling oscillates, a downward load acts on the lower edge of the caisson side surface, so that rotation can be suppressed and the restoring force can be increased.

  The vibration reduction device 2 is mounted on a calm water surface by lifting the upper ends of the suspension members 3 and 3 with a crane and keeping the upper ends of the suspension members 3 on the upper surface of the caisson in a state where the upper ends are aligned with the predetermined positions on the side surfaces of the caisson. It fixes to the suspension material connection part 7 and 7 installed beforehand.

  To remove the sway reduction device 2 after towing to the installation site, the upper end of one suspension member 3 is unfastened while the caisson 1 is lifted, and the other end is lifted by a crane. At this time, since the suspension members 3 and 3 are connected by the lateral connection member 5, the entire sway reduction device 2 can be simultaneously retracted from the caisson and collected. The recovered sway reduction device 2 can be reused for towing another caisson.

  In the above-described embodiment, the movement restricting member that constitutes the rotation center of the free hanging long portion 3b of the both suspension members 3 and 3 is configured with the lateral connection member 5 connected to both suspension members 3 and 3, In addition, any suspension material such as a ring fixed to the lower edge portion of the caisson side surface may be used as long as it can guide so as not to deviate from a predetermined position of the lower edge of the caisson side surface.

G1, G2 Center of gravity 1 Caisson 1a Side surface 2 Oscillation reducing device 3 Suspension material 3a Caisson height long part 3b Free hanging long part 4 Weight 5 Lateral connecting material (movement restricting member)
6 Front-rear direction movement restriction guide

Claims (3)

  A pair of suspension members whose bottom ends are suspended below the lower side edge of the caisson along the both side surfaces of the caisson floated on the water surface, weights suspended from the lower ends of the suspension members, and the caisson of the suspension members And a movement restricting member that constitutes the center of rotation of the lower free hanging portion on the lower side, and is configured to detachably connect the upper ends of the suspension members to the upper portion of the caisson.   2. The vibration reduction device according to claim 1, wherein the movement restricting member is configured by a laterally connected member whose both ends are connected to each suspension member at the lower edge positions of both side surfaces of the caisson.   The sway reduction device according to claim 1 or 2, wherein movement of the both suspension members in the front-rear direction is restricted by a front-rear direction movement restriction guide fixed to the position of the lower side edge of the caisson.

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