Caisson mounting system

Abstract

To provide a caisson installation system capable of reducing the influence of waves in caisson installation work.SOLUTION: The caisson installation system 1 includes a pontoon 2, a horizontal portion 5 formed to be recessed forward from a rear end of the pontoon with a dimension capable of accommodating a caisson 10, a rope 9 as an example of a fixing portion for fixing the caisson 10 in the horizontal portion 5, and a thruster 3 as an example of a propulsion portion for advancing the pontoon 2 in an arbitrary direction in a horizontal direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a caisson installation system. [Background technology]

[0002] Conventionally, there is a construction method in which a caisson is installed at an installation position on the bottom of the water, such as the seabed. In this construction method, the caisson is towed by a ship or the like while floating on the water, and once it is transported close to the installation position, its posture and position are adjusted by pulling ropes and wires from multiple directions and injecting water into the interior, and it is finally installed at the installation position (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-113744 Summary of the Invention [Problem to be solved by the invention]

[0004] With conventional caisson installation methods, the caisson being installed and the ship towing it can be affected by waves. For example, if the vertical movement of the caisson or ship due to waves exceeds the work limit, resulting in periods when construction cannot be carried out, the efficiency of the caisson installation work will decrease. Furthermore, if work is carried out while the caisson or ship is rocking due to the effects of waves, the safety of the caisson installation work may be reduced.

[0005] The present disclosure aims to provide a caisson installation system that can reduce the impact of waves on caisson installation work. [Means for solving the problem]

[0006] A caisson installation system according to one aspect of an embodiment of the present invention comprises a barge, a flat water section formed by recessing from the front end of the barge along the rearward in a size sufficient to accommodate a caisson, a fixing section for fixing the caisson within the flat water section, and a propulsion section for moving the barge in any horizontal direction. [Effects of the Invention]

[0007] According to the present disclosure, a caisson installation system can be provided that can reduce the impact of waves on caisson installation work. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a caisson installation system according to a first embodiment. [Figure 2] FIG. 1 shows the first stage of the caisson installation procedure in the first embodiment. [Figure 3] FIG. 1 shows the second stage of the caisson installation procedure in the first embodiment. [Figure 4] FIG. 10 is a diagram showing the third stage of the caisson installation procedure in the first embodiment. [Figure 5] FIG. 10 is a diagram showing the fourth stage of the caisson installation procedure in the first embodiment. [Figure 6] FIG. 10 is a diagram showing the fifth stage of the caisson installation procedure in the first embodiment. [Figure 7] FIG. 6 shows the sixth step of the caisson installation procedure in the first embodiment. [Figure 8] FIG. 7 shows the seventh stage of the caisson installation procedure in the first embodiment. [Figure 9] FIG. 10 is a diagram showing a schematic configuration of a caisson installation system according to a second embodiment. [Figure 10] FIG. 10 shows the first stage of the caisson installation procedure in the second embodiment. [Figure 11] FIG. 10 shows the second stage of the caisson installation procedure in the second embodiment. [Figure 12] FIG. 10 shows the third stage of the caisson installation procedure in the second embodiment. [Figure 13]FIG. 10 shows the fourth stage of the caisson installation procedure in the second embodiment. [Figure 14] FIG. 10 shows the fifth stage of the caisson installation procedure in the second embodiment. [Figure 15A] FIG. 6 shows the sixth step of the caisson installation procedure in the second embodiment. [Figure 15B] FIG. 6 shows the sixth step of the caisson installation procedure in the second embodiment. [Figure 16] FIG. 7 shows the seventh stage of the caisson installation procedure in the second embodiment. [Figure 17] FIG. 10 is a diagram showing a schematic configuration of a dredging system according to a third embodiment. [Figure 18] FIG. 10 is a diagram showing the first stage of dredging work in the third embodiment. [Figure 19] FIG. 10 is a diagram showing a second stage of dredging work in the third embodiment. [Figure 20] FIG. 10 is a diagram showing a third stage of dredging work in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0010] In the following description, the X, Y, and Z directions are perpendicular to each other. The X and Y directions are horizontal, and the Z direction is vertical. The X direction is the fore-and-aft direction of the barge 2, with the X positive direction side being the stern side of the barge 2 and the X negative direction side being the bow side of the barge 2. The Y direction is the width direction of the barge 2. For ease of explanation, the Z positive direction side may also be referred to as the upper side and the Z negative direction side as the lower side.

[0011] [First embodiment] The first embodiment will be described with reference to FIGS.

[0012] Figure 1 is a diagram showing the schematic configuration of a caisson installation system 1 according to the first embodiment. Figure 1(A) is a side view seen from the Y positive direction side, Figure 1(B) is a plan view seen from the Z positive direction side (top side), and Figure 1(C) is a front view seen from the X positive direction side.

[0013] The caisson installation system 1 is a system for installing a caisson 10 at an installation position such as a mound 22 provided on the bottom 21 of a body of water, such as the seabed (see Figure 5, etc.). The caisson 10 is a box-shaped structure made of reinforced concrete or the like. The mound 22 is the foundation of a port structure constructed mainly by dumping rubble into the bottom 21 of the body of water. In the following explanation, as an example of a caisson installation method, a continuous box installation work will be explained, in which multiple caissons 10, 20 are installed adjacent to each other in a predetermined direction.

[0014] As shown in Figure 1, the caisson installation system 1 of the first embodiment includes a barge 2. The barge 2 is a vessel that houses and tows a caisson 10, as shown by the dashed line in Figure 1. In Figure 1, the stern of the barge 2 is located on the positive X side, and the bow of the barge 2 is located on the negative X side.

[0015] The bow section 2A on the bow side of the barge 2 extends across the entire width of the barge 2 and is configured to have a front end surface at a predetermined position in the X direction. A bridge 2B, in which the barge 2's control room and other components are located, is erected on the bow section 2A.

[0016] The barge 2 is provided with a flat water section 5, which is recessed from the aft end of the barge 2 (the stern on the X square side in FIG. 1 ) forward (toward the bow 2A in the negative X direction) and is large enough to accommodate the caisson 10. A pair of longitudinal sections 4A, 4B extending toward the aft are formed at both ends of the aft end surface of the bow 2A in the width direction. Each of the pair of longitudinal sections 4A, 4B has a substantially constant width and is arranged substantially parallel along the X direction. As a result, the flat water section 5 is formed between the pair of longitudinal sections 4A, 4B with a substantially constant width and extending in the X direction. The innermost part of the flat water section 5 in the X direction is the aft end surface of the bow 2A, and the side of the flat water section 5 is the side of the pair of longitudinal sections 4A, 4B facing the center of the hull. The frontmost part of the flat water section 5 is open at the stern of the barge 2. Furthermore, the flat water section 5 is formed by vertically penetrating the hull of the barge 2, and is formed in a roughly U-shape with an opening on the stern side in a plan view. With this configuration, the flat water section 5 can accommodate the caisson 10 through the opening at the stern of the barge 2. In this embodiment, by accommodating the caisson 10 in the flat water section 5 and fixing it to the hull, the barge 2 can tow the caisson 10.

[0017] The barge 2 is also provided with a connecting section 6 that connects the rear (X-positive direction) sections of a pair of longitudinal sections 4A, 4B that extend in the fore-and-aft direction of the barge 2, sandwiching the flatwater section 5 therebetween. The connecting section 6 is provided on the barge 2 and is formed at a height that allows the caisson 10 to pass through. As shown in FIG. 1(C), the connecting section 6 has a pair of upright sections 6A, 6B that extend upward from the upper surfaces of the pair of longitudinal sections 4A, 4B, and a beam section 6C that horizontally connects the pair of upright sections 6A, 6B. Here, "a height that allows the caisson 10 to pass through" means that, when the barge 2 is movably floating on the water, the height position of the lower end of the beam section 6C of the connecting section 6 is higher than the height position of the box-shaped upper surface of the caisson 10, which is also floating on the water. The connecting section 6 also needs to be formed so that the widthwise distance between the pair of upright sections 6A, 6B of the connecting section 6 is greater than the width dimension of the caisson 10. By providing the connecting part 6 in this manner, it is possible to move the caisson 10 that has entered the flat water section 5 from the opening at the rear end of the flat water section 5 toward the bow of the flat water section 5 beyond the connecting part 6. Furthermore, the connecting part 6 prevents the pair of longitudinal parts 4A, 4B on the stern side of the barge 2 from bending in the width direction, which would change the spacing between the rear parts of the pair of longitudinal parts 4A, 4B, and therefore prevents a decrease in the rigidity of the part of the hull of the barge 2 where the flat water section 5 is located. Therefore, by providing the connecting part 6, it is possible to prevent the hull of the barge 2 from bending and to move the caisson 10 in and out of the flat water section 5 at the same time.

[0018] The barge 2 is provided with a thruster 3 (propulsion unit). The thruster 3 is an example of a propulsion device that moves the barge 2 in any horizontal direction. As shown in FIG. 1(A), the thrusters 3 are installed on the bottom of the bow and stern of the barge 2, for example. As shown in FIG. 1(C), the thrusters 3 are installed on both sides of the width of the barge 2, for example. The thrusters 3 can be, for example, an azimuth thruster with a propeller that rotates 360 degrees horizontally, or a propeller (side thruster) facing sideways to move the hull sideways (Y direction).

[0019] As shown by the dotted rectangle in Figure 1 (A), a water injection section 7 (descending section) is provided inside the barge 2. The water injection section 7 is a device that can store water inside and can discharge the water stored inside to the outside of the hull. The water injection section 7 is an example of a descending section that can store water inside and increase the weight of the hull, thereby lowering the barge 2 relative to the water surface 23. Note that the volume of the water injection section 7 is preferably formed to be large enough to inject water when the caisson 10 is installed so that the barge 2, with the caisson 10 fixed to the flat water section 5, can be lowered to its maximum draft.

[0020] As shown in Figures 1(A) and 1(C), a foldable curtain 8 is installed on the bottom of the barge 2. The upper end of the curtain 8 is the part that connects to the bottom of the barge 2, and it is stored in a folded state at the upper end during normal operation, including when the barge 2 is moving. As shown by the dotted line in Figure 1(B), the curtain 8 is installed in a U-shape in plan view, surrounding the side of the longitudinal section 4A facing the center of the hull, the aft end face of the bow section 2A, and the side of the longitudinal section 4B facing the center of the hull. When the caisson 10 is installed, the curtain 8 is unfolded downward from its folded state and functions as a covering that covers the gap between the bottom of the barge 2 and the water bottom 21.

[0021] Next, with reference to Figs. 2 to 8, a procedure for installing the caisson 10 using the caisson installation system 1 of the first embodiment will be described.

[0022] Figure 2 is a diagram showing the first stage of the caisson installation procedure in the first embodiment, where Figure 2(A) is a side view seen from the Y negative direction side, and Figure 2(B) is a plan view seen from the Z positive direction side.

[0023] As mentioned above, the continuous box installation work will be explained as an example of the caisson installation method. Therefore, as a prerequisite for the first stage, a flat-topped mound 22 is provided on the bottom 21 of the water, such as the seabed, and multiple existing caissons 20 are installed continuously on the top surface of the thus formed mound 22. In the example of Figure 2, three existing caissons 20A, 20B, and 20C are installed adjacent to each other in a row along the X direction.

[0024] As shown in FIG. 2 , in the first stage, a caisson 10 to be newly installed next to the existing caisson 20 is fixed to the hull at a position in front of the connecting section 6 in the flat water section 5 of the barge 2 and toward the stern of the hull. The caisson 10 is connected at one end to the rope 9, for example, and at the other end to the hull. In the example of FIG. 2 , the other ends of two ropes 9 are connected to the longitudinal section 4A, and the other ends of the other two ropes 9 are connected to the longitudinal section 4B, thereby fixing the caisson 10 to the hull at four points. As shown in FIG. 2 , two of the four box-shaped sides of the caisson 10 are positioned opposite the sides of the longitudinal sections 4A and 4B, respectively, and the remaining side faces the stern of the barge 2 (the positive X direction). The rope 9 is an example of a fixing part for fixing the caisson 10 in the flat water section 5. Elements other than ropes, such as wires, may be used as long as they fulfill the function of a fixing part.

[0025] With the caisson 10 fixed in the flat water section 5 by the four ropes 9 in this way, the barge 2 moves in a direction approaching the existing caisson 20 as shown by arrow A in Figure 2, and tows the caisson 10. By positioning the caisson 10 on the stern side of the flat water section 5 as shown in Figure 2, it is possible to easily move the caisson 10 close to a position adjacent to the existing caisson 20 in subsequent processes.

[0026] Figure 3 is a diagram showing the second stage of the caisson installation procedure in the first embodiment. Figures 3(A) and (B) are generally similar to Figures 2(A) and (B).

[0027] As shown in FIG. 3, in the second stage, the barge 2 is positioned so that the caisson 10 is adjacent to the existing caisson 20. At this time, the position of the barge 2 relative to the existing caisson 20 is adjusted by the multiple thrusters 3. Through this position adjustment, one of the multiple existing caissons 20, caisson 20C, which is located furthest in the X-negative direction, enters the flat water section 5 through the opening at the stern of the barge 2, and the caisson 10 is positioned so that the side of the box-shaped existing caisson 20C facing the X-negative direction faces and makes surface contact with the side of the box-shaped caisson 10 facing the X-positive direction. Furthermore, at this position, the barge 2 is fixed to the water bottom 21 by multiple anchors 11. As shown in FIG. 3(B), in this example, the barge 2 is fixed by four anchors 11 at the tip ends of the pair of longitudinal sections 4A, 4B and on both widthwise sides of the aft end of the bow section 2A.

[0028] In the caisson installation system 1 of the first embodiment, the caisson 10 and the surrounding area of ​​the flat water section 5 are surrounded by a pair of longitudinal sections 4A, 4B and the bow section 2A of the barge 2. Therefore, when the barge 2 stops and positioning is performed as in the second stage, as shown in Figure 3(A), the up and down movement of the water surface 23 within the flat water section 5 is gentler than outside the barge 2. This makes it possible to suppress the effect of waves on the positioning work of the caisson 10.

[0029] Figure 4 is a diagram showing the third stage of the caisson installation procedure in the first embodiment. Figures 4(A) and (B) are generally similar to Figures 2(A) and (B).

[0030] As shown by hatching in Figure 4(A), in the third stage, water is injected into the water injection section 7 of the barge 2. As a result, as shown by arrow B in Figure 4(A), the barge 2 descends to its maximum draft relative to the water surface 23. This allows the bottom of the caisson 10 to approach a position directly above the top surface of the mound 22, making it possible to easily and accurately place the caisson 10 on the mound 22 in the fourth stage described below.

[0031] Furthermore, as shown by arrow C in Figure 4(A), the curtain 8 on the bottom of the barge 2 is deployed downward, and extends to a position where the lower end of the curtain 8 contacts the water bottom 21. As a result, as shown in Figure 4(B), the curtain 8 is arranged to surround the flat water section 5, so that the caisson 10 and the water surface 23 of the flat water section 5 around it are surrounded by the pair of longitudinal sections 4A, 4B and bow section 2A of the barge 2 and the curtain 8 below it. This blocks waves outside the barge 2 from the area around the caisson 10, further suppressing the effects of waves and further suppressing the up and down movement of the caisson 10 and the water surface 23 of the flat water section 5 around it.

[0032] In the third stage, the ropes 9 are gradually loosened in accordance with the sinking of the caisson 10 due to the injection of water into the water injection section 7. At this time, the tension in the ropes 9 is maintained such that they are tensioned to such an extent that they will not break.

[0033] Figure 5 is a diagram showing the fourth stage of the caisson installation procedure in the first embodiment. Figures 5(A) and (B) are generally similar to Figures 2(A) and (B).

[0034] As shown in Figure 5(B), in the fourth stage, the connection between the caisson 10 and the longitudinal sections 4A, 4B of the barge 2 by the rope 9, which was gradually loosened in the third stage, is finally released. As a result, as shown by arrow D in Figure 5(A), the caisson 10, which was fixed to the hull, sinks downward in the water and is placed in its installation position on the mound 22. At this time, as explained with reference to Figure 4, the caisson 10 and the water surface 23 around it are surrounded by the flat water section 5 and the curtain 8 below it, which blocks the transmission of waves outside the barge 2. This suppresses the influence of waves on the caisson 10 and the surrounding area, and prevents the caisson 10 from shifting from its desired installation position due to the influence of waves while it is sinking.

[0035] Figure 6 is a diagram showing the fifth step of the caisson installation procedure in the first embodiment. Figures 6(A) and (B) are generally similar to Figures 2(A) and (B).

[0036] In the fifth stage, the curtain 8 is folded toward the bottom of the ship, and the water accumulated in the water injection section 7 in the third stage of Fig. 4 is discharged to the outside of the hull. As a result, the draft of the barge 2 decreases as shown by arrow E in Fig. 6(A), and the barge rises relative to the water surface 23.

[0037] Then, as shown by arrow F in Figures 6(A) and (B), the barge 2 moves in the negative X direction, and the barge 2 moves away from the existing caisson 20 and the newly installed caisson 10.

[0038] Fig. 7 is a diagram showing a sixth step in the caisson installation procedure in the first embodiment. Fig. 7 is a picture seen from the X positive direction side, and shows a cross section of the caisson 10.

[0039] As shown in Fig. 7, the interior of the caisson 10 is divided into a plurality of compartments 10A. In Fig. 7, four compartments 10A to 10D are shown, which are divided approximately equally along the Y direction.

[0040] In the sixth stage, the filling of the caisson 10 is carried out. As shown in Figure 7, an earth and sand carrier 30 is moored alongside the caisson 10. A crane 31 is installed on the earth and sand carrier 30, and the tip of the boom of the crane 31 can be moved to any position above the caisson 10 by rotating the rotating body of the crane 31 around a vertical axis of rotation and by moving the boom of the crane 31 up and down around a horizontal axis of rotation. A bucket 32 ​​is connected to the tip of a wire hanging downward from the tip of the boom. The bucket 32 ​​grabs the sand 12 loaded on the earth and sand carrier 30, moves to a position above the desired compartments 10A to 10D by the crane 31, and opens at that position to deposit the sand 12 into the compartments 10A to 10D. Figure 7 illustrates a state in which sand 12 has been poured up to the midpoint of the three compartments 10B, 10C, and 10D on the negative Y side of the four compartments, and the remaining compartment 10A does not yet contain sand 12. However, during the filling work, it is common to pour sand 12 evenly into each of the compartments 10A to 10D of the caisson 10. The sixth stage of filling work continues until the sand 12 reaches the top of each of the compartments 10A to 10D.

[0041] Furthermore, in the sixth stage, it is preferable to drape a protective sheet 33 between the caisson 10 and the earth and sand carrier 30 so as to cover the water surface 23. This prevents the sand 12 from falling into the water while being moved from the earth and sand carrier 30 to the caisson 10 during the filling work, thereby suppressing the occurrence of pollution.

[0042] 8 is a diagram showing a seventh step of the caisson installation procedure in the first embodiment. The outline of FIG. 8 is the same as FIG.

[0043] In the seventh stage, the concrete cover is poured. As shown in Figure 8, a mixer ship 40 is moored alongside the caisson 10. The mixer ship 40 has a tank 41 that stores ready-mixed concrete, a distributor 42 that discharges the concrete from the tank 41 to the outside, and a hose 43 that is connected to the tip of the distributor 42.

[0044] As shown in FIG. 8, a worker P standing on a scaffolding 44 installed at the upper ends of the compartments 10A-10D where filling work has been completed operates a hose 43 to inject concrete 13 from the hose 43 into the upper ends of the compartments 10A-10D to cast concrete covers. FIG. 8 illustrates a state in which concrete covers 14A and 14B have been cast for the two compartments 10A and 10B on the Y-positive side of the four compartments, respectively, and a worker P standing on a scaffolding 44 is casting concrete 13 in compartment 10C. The seventh stage of concrete cover casting work continues until covers have been cast for all compartments 10A-10D. When the seventh stage of cover casting work is completed, the mixer vessel 40 moves away from the caisson 10, completing the caisson installation work of the first embodiment.

[0045] The caisson installation system 1 of the first embodiment comprises a barge 2, a flat water section 5 formed by a depression extending from the rear end of the barge along the front with dimensions large enough to accommodate a caisson 10, a rope 9 as an example of a fixing section for fixing the caisson 10 within the flat water section 5, and a thruster 3 as an example of a propulsion section for moving the barge 2 in any horizontal direction.

[0046] With this configuration, the caisson 10 can be housed within the flat water section 5 surrounded by the hull of the barge 2, so that the hull of the barge 2 can prevent waves generated outside the barge 2 from reaching the caisson 10 and the area of ​​the flat water section 5 surrounding the caisson 10. This suppresses the up and down movement of the water surface 23 around the caisson 10, preventing unexpected rocking of the caisson 10 and allowing work to install the caisson 10 to be carried out more stably. As a result, the caisson installation system 1 of the first embodiment can reduce the impact of waves on caisson installation work.

[0047] [Second embodiment] The second embodiment will be described with reference to FIGS.

[0048] Figure 9 is a diagram showing the schematic configuration of a caisson installation system 1A according to the second embodiment. The outlines of Figures 9(A) and (B) are similar to Figures 1(A) and (B). Figure 9(C) is a cross-sectional view taken along line AA in Figure 9(A), showing the portion of the barge 2 on which the gantry crane 15 is located, viewed from the X-negative side. Furthermore, explanations of the components of the caisson installation system 1A according to the second embodiment that are the same as those of the caisson installation system 1 according to the first embodiment will be omitted.

[0049] As shown in FIG. 9, the caisson installation system 1A of the second embodiment includes a gantry crane 15. The gantry crane 15 is installed so as to be movable along the extension direction of a pair of longitudinal sections 4A, 4B of the barge 2. The gantry crane 15 has a pair of pillars 15A, 15B, a beam 15C, and a moving section 15D. The pair of pillars 15A, 15B are members arranged to extend vertically on the pair of longitudinal sections 4A, 4B, respectively. The beam 15C connects the pair of pillars 15A, 15B at the same height position as the pair of pillars 15A, 15B, and is a member arranged to extend horizontally (Y direction). The moving section 15D is connected to the lower ends of the pair of pillars 15A, 15B.

[0050] Guiding units 16A and 16B are provided on the upper surfaces of the pair of longitudinal sections 4A and 4B of the barge 2. The guiding units 16A and 16B are installed to extend along the extension direction (X direction) of the longitudinal section 4A. The ends of the guiding units 16A and 16B on the X negative side are arranged at a position on the bow section 2A of the barge 2, and the ends on the X positive side are arranged at a position just before the coupling unit 6. The moving units 15D, which are connected to the lower ends of the pair of pillars 15A and 15B of the gantry crane 15, respectively, are coupled to the guiding units 16A and 16B so as to be movable along the guiding units 16A and 16B, respectively.

[0051] Here, any elements can be used for moving unit 15D and guide units 16A and 16B as long as they can realize the function of moving unit 15D in the X direction along guide units 16A and 16B. For example, if rails are used as guide units 16A and 16B, wheels rotatably installed on the rails can be used as moving unit 15D. Alternatively, if grooves recessed into the upper surfaces of longitudinal units 4A and 4B are used as guide units 16A and 16B, protrusions formed to protrude downward from the lower ends of paired pillar units 15A and 15B and installed by engaging with the grooves can be used as moving unit 15D.

[0052] The gantry crane 15 is installed on the barge 2 so as to be movable in the X direction along the guide sections 16A and 16B via the moving section 15D. The gantry crane 15 is also capable of suspending the caisson 10. Therefore, the gantry crane 15 is an example of a moving section that can move the caisson 10 housed in the flat water section 5 in the fore-and-aft direction of the barge 2.

[0053] By including such a gantry crane 15, the caisson installation system 1A of the second embodiment can move the caisson 10 to any position in the X direction within the flat water section 5 during installation work of the caisson 10. As a result, when the caisson 10 is fixed within the flat water section 5 and the barge 2 moves to tow the caisson 10, the caisson 10 is not limited to a position suitable for installation work, but can be fixed to any position in the X direction within the flat water section 5. Since the caisson 10 can be fixed to any position that makes it easy to balance the fore-and-aft direction of the hull of the barge 2, the caisson 10 can be towed efficiently by the barge 2.

[0054] Furthermore, the caisson installation system 1A of the second embodiment may be configured to include a filling bucket 18 that is suspended from the beam 15C of the gantry crane 15 and is movable along the beam 15C during the filling step of the caisson installation procedure (see Figure 15B). The filling bucket 18 corresponds to the bucket 32 ​​of the earth and sand carrier 30 described in the first embodiment with reference to Figure 7. The beam 15C extends to the outside in the width direction of the barge 2, and the filling bucket 18 is movable to the outside of the barge 2 in the width direction.

[0055] In the second embodiment of the caisson installation system 1A, by providing a filling bucket 18 on the gantry crane 15, i.e., by providing a filling bucket 18 on the barge 2, there is no need to provide a crane on the soil transport ship 30A (see Figure 15B) that transports the sand 12 to be filled, which relaxes restrictions on the ships that can be used for filling work and improves the convenience of filling work after the caisson 10 is placed.

[0056] Furthermore, the caisson installation system 1A of the second embodiment may be configured to include a distributor 42 that is suspended from the beam 15C of the gantry crane 15 and that dispenses concrete 13 to be poured into the caisson 10. For example, this configuration can be realized (see FIG. 16) by connecting the distributor 42 of the mixer vessel 40 described in the first embodiment with reference to FIG. 8 to the mobile hoisting mechanism 17 of the gantry crane 15 (see FIG. 15B). With this configuration, the position of the tip of the distributor 42 can be adjusted to any position in the X direction by moving the gantry crane 15 in the X direction, and can also be adjusted to any position in the Y direction by moving the mobile hoisting mechanism 17 on the beam 15C in the Y direction, thereby facilitating the work of pouring concrete 13 to provide a lid 14 on the caisson 10.

[0057] Next, the procedure for installing the caisson 10 using the caisson installation system 1A of the second embodiment will be described with reference to Figures 10 to 16. Also, in the second embodiment, similarly to the first embodiment, continuous box installation work will be described as an example.

[0058] Figure 10 is a diagram showing the first stage of the caisson installation procedure in the second embodiment, where Figure 10(A) is a side view seen from the Y negative direction, and Figure 10(B) is a plan view seen from the Z positive direction.

[0059] As shown in Figure 10, in the first stage, a caisson 10 to be newly installed next to the existing caisson 20 is fixed to the hull at a position approximately in the center of the fore-and-aft direction of the hull in the flat water section 5 of the barge 2. As in the first embodiment, the caisson 10 is arranged so that two of the four box-shaped sides face the sides of the longitudinal sections 4A and 4B, respectively, and the remaining side faces the stern side (positive X direction) of the barge 2. Also, as in the first embodiment, the caisson 10 is connected and fixed to the longitudinal sections 4A and 4B of the barge 2 by four ropes 9, which are an example of fixing sections.

[0060] Furthermore, in the first stage, it is preferable that the moving section 15D of the gantry crane 15 is disposed at the end of the rails 16A, 16B on the X negative side, and thus the gantry crane 15 is disposed on the bow section 2A of the barge 2 and its movement in the X direction is restricted. This makes it possible to prevent unnecessary movement of the gantry crane 15 due to movement or swinging of the barge 2.

[0061] With the caisson 10 fixed in the flat water section 5 by the four ropes 9 in this way, the barge 2 moves in a direction approaching the existing caisson 20 as shown by arrow A in Figure 10, and tows the caisson 10. As shown in Figure 10, by positioning the caisson 10 at approximately the center of the fore-and-aft direction of the hull, the balance of the hull in the fore-and-aft direction can be stabilized and the caisson 10 can be towed, making it easier for the barge 2 to tow the caisson 10.

[0062] Figure 11 is a diagram showing the second stage of the caisson installation procedure in the second embodiment. Figures 11(A) and (B) are generally similar to Figures 10(A) and (B).

[0063] As shown in FIG. 11 , in the second stage, after the barge 2 approaches the existing caisson 20, the position of the barge 2 relative to the existing caisson 20 is adjusted by the multiple thrusters 3. Through this position adjustment, one caisson 20C, which is located furthest in the X-negative direction among the multiple existing caissons 20, enters the flat water section 5 through the opening at the stern of the barge 2, and the barge 2 is positioned so that the side of the box-shaped existing caisson 20C facing the X-negative direction faces the side of the box-shaped caisson 10 facing the X-positive direction. Furthermore, at this position, the barge 2 is fixed to the water bottom 21 by multiple anchors 11. As shown in FIG. 11(B) , in this example, the barge 2 is fixed by four anchors 11 at the tip ends of the pair of longitudinal sections 4A, 4B and on both widthwise sides of the front end of the bow section 2A.

[0064] In the caisson installation system 1A of the second embodiment, as in the first embodiment, the caisson 10 and the surrounding area of ​​the flat water section 5 are surrounded by a pair of longitudinal sections 4A, 4B and the bow section 2A of the barge 2. Therefore, when the barge 2 stops and is positioned as in the second stage, the up and down movement of the water surface 23 within the flat water section 5 is gentler than outside the barge 2, as shown in Figure 11(A).

[0065] Figure 12 is a diagram showing the third stage of the caisson installation procedure in the second embodiment. Figures 12(A) and (B) are generally similar to Figures 10(A) and (B).

[0066] As shown by hatching in Figure 12(A), in the third stage, water is injected into the water injection section 7 of the barge 2. As a result, as shown by arrow B in Figure 12(A), the barge 2 descends to its maximum draft relative to the water surface 23. As a result, the bottom of the caisson 10 approaches a position directly above the top surface of the mound 22.

[0067] 12(A), the curtain 8 on the bottom of the barge 2 is deployed downward, and extends to a position where the lower end of the curtain 8 contacts the water bottom 21. As a result, as shown in FIG. 12(B), the curtain 8 is arranged to surround the flat water section 5, so that the caisson 10 and the water surface 23 of the flat water section 5 around it are surrounded by the pair of longitudinal sections 4A, 4B and bow section 2A of the barge 2 and the curtain 8 below it. This blocks waves outside the barge 2 from the area around the caisson 10, further suppressing the effects of waves and further suppressing the up and down movement of the caisson 10 and the water surface 23 of the flat water section 5 around it.

[0068] Figure 13 is a diagram showing the fourth stage of the caisson installation procedure in the second embodiment. Figure 13(A) is outlined similarly to Figure 10(A). Figure 13(B) is a cross-sectional view of the portion of the barge 2 on which the gantry crane 15 is placed, viewed from the X-negative side, and corresponds to Figure 9(C).

[0069] In the fourth stage, as shown by arrow G in Figure 13(A), the gantry crane 15 on the barge 2 moves in the positive X direction to the position where the caisson 10 is fixed. After that, two wires 19 are connected between the beam 15C of the gantry crane 15 and the upper surface of the caisson 10. As shown in Figure 13(B), it is preferable that the two wires 19 are positioned in the Y direction at approximately the same distance from the beam 15C and the center of the caisson 10 in the Y direction. This makes it possible to prevent the caisson 10 from tilting in the Y direction when the caisson is suspended by the beam 15C via the wires 19, and allows the caisson 10 to be suspended in a balanced manner.

[0070] After that, the connection between the caisson 10 and the longitudinal sections 4A, 4B of the barge 2 by the ropes 9 is released. As a result, the caisson 10 is suspended by the beam section 15C of the gantry crane 15 via the wires 19, with the lower section submerged in water.

[0071] As described above, the caisson 10 and the water surface 23 of the surrounding flat water section 5 are surrounded by the pair of longitudinal sections 4A, 4B and bow section 2A of the barge 2, and the curtain 8 below them. This allows the up and down movement of the caisson 10 and the water surface 23 of the surrounding flat water section 5 to be smoothed, so that the work of connecting the caisson 10 and the gantry crane 15 with the wire 19 in the fourth stage can be carried out more stably and with greater precision, suppressing the effects of waves.

[0072] In the example of Figure 13, the upper ends of the two wires 19 are directly connected to the beam 15C of the gantry crane 15, but they may be installed so as to be movable along the extension direction (Y direction) of the beam 15C via a device similar to the mobile hoisting mechanism 17 (see Figure 15B) described below. This configuration improves the degree of freedom in positioning the wires 19 in the Y direction. Also, the caisson 10 may be suspended by three or more wires 19.

[0073] Figure 14 is a diagram showing the fifth step of the caisson installation procedure in the second embodiment. Figures 14(A) and (B) are generally similar to Figures 10(A) and (B).

[0074] In the fifth stage, as shown by arrow H in Figure 14, the gantry crane 15 suspending the caisson 10 moves from the position where the caisson 10 was fixed to the stern side of the barge 2. As a result, the caisson 10 is positioned in the X direction so that the side of the box shape of the caisson 10 facing the X positive direction is in face-to-face contact with the side of the box shape of the existing caisson 20C facing the X negative direction.

[0075] As described above, the caisson 10 and the water surface 23 of the surrounding flat water section 5 are surrounded by the pair of longitudinal sections 4A, 4B and bow section 2A of the barge 2, and the curtain 8 below them. This allows the up and down movement of the caisson 10 and the water surface 23 of the surrounding flat water section 5 to be smoothed, so that the positioning work of the caisson 10 in the fifth stage can be carried out more stably and with higher precision, suppressing the effects of waves.

[0076] The fixed position of the barge 2 relative to the existing caisson 20 is preferably determined so that the X-direction position of the caisson 10 is at the fifth stage position when the moving part 15D of the gantry crane 15 reaches the end position on the X-positive side of the rails 16A, 16B. This allows the positioning of the caisson 10 in the fifth stage to be performed easily and accurately.

[0077] Figures 15A and 15B are diagrams showing the sixth step of the caisson installation procedure in the second embodiment. Figures 15A and 15B are outlined similarly to Figures 13(A) and (B).

[0078] In the sixth stage, the connection between the beam 15C of the gantry crane 15 and the caisson 10 by the two wires 19 is released. As a result, as shown by arrow I in Figure 15A, the caisson 10 that was suspended from the beam 15C falls downward in the water and is placed in the installation position on the mound 22.

[0079] Thereafter, as shown in Figure 15B, an earth and sand carrier 30A is moored alongside the barge 2, and the filling work of the caisson 10 is carried out. The earth and sand carrier 30A is loaded with sand 12 to be filled. In the second embodiment, the work of pouring the sand 12 into the caisson 10 is carried out using a filling bucket 18 provided on the gantry crane 15, so the earth and sand carrier 30A does not need to be equipped with a crane. In the example of Figure 15B, the earth and sand carrier 30A is moored alongside the barge 2 and the caisson 10 on the negative Y side, and directly below the beam 15C of the gantry crane 15.

[0080] In the filling work, first, a filling bucket 18 is attached to the gantry crane 15. In the example of FIG. 15B, a mobile hoisting mechanism 17 is installed on the top of the beam 15C. The mobile hoisting mechanism 17 has a built-in drive source such as a motor, and is capable of moving along the extension direction (Y direction) of the beam 15C by the drive force output by the drive source. The mobile hoisting mechanism 17 also has a hoisting device such as a winch, and can hoist and lower the wire 17A that hangs directly below. The filling bucket 18 is connected to the lower end of the wire 17A, and is configured to be openable and closable by the mobile hoisting mechanism 17.

[0081] Next, as shown by the dotted line in Figure 15B, the mobile hoisting mechanism 17 moves to the end of the beam 15C of the gantry crane 15 in the negative Y direction, and moves to a position directly above the earth and sand carrier 30A. At this position, the mobile hoisting mechanism 17 winds down the wire 17A, and lowers the filling bucket 18 connected to the lower end of the wire 17A to the height above the earth and sand carrier 30A at which the sand 12 is loaded. The filling bucket 18 grabs the sand 12 on the earth and sand carrier 30A.

[0082] Thereafter, the mobile hoisting mechanism 17 winds up the wire 17A to raise the filling bucket 18 to a position above the upper surface of the longitudinal section 4A of the barge 2, and then, as shown by arrow J in Figure 15B, the mobile hoisting mechanism 17 moves along the beam section 15C in the Y positive direction to a position directly above any one of the multiple compartments 10A to 10D of the caisson 10. In the example of Figure 15B, the mobile hoisting mechanism 17 is positioned directly above the second compartment 10C from the Y negative side.

[0083] Thereafter, the mobile hoisting mechanism 17 winds down the wire 17A, lowering the filling bucket 18 connected to the lower end of the wire 17A to a position directly above the compartment 10C. At this position, the filling bucket 18 is opened, and the sand 12 is poured into the compartment 10C. Figure 15B illustrates a state in which sand 12 has been poured up to the midpoint of the three compartments 10B, 10C, and 10D on the negative Y side of the four compartments, and the remaining compartment 10A does not yet contain sand 12. The sixth stage of filling work continues until the sand 12 reaches the top of each of the compartments 10A to 10D. When the filling work is completed, the soil transport ship 30A moves away from the barge 2.

[0084] In the sixth stage, after the filling work is completed, the filling bucket 18, the mobile hoisting mechanism 17, etc. are removed from the gantry crane 15.

[0085] Figure 16 is a diagram showing the seventh stage of the caisson installation procedure in the second embodiment. The outline of Figure 16 is similar to Figure 15B.

[0086] In the seventh stage, the concrete cover is poured. As shown in FIG. 16, a mixer ship 40 is moored alongside the barge 2. In the example of FIG. 16, the mixer ship 40 is moored alongside the barge 2 and the caisson 10 in a position on the negative Y-direction side. In the second embodiment, a distributor 42 for discharging concrete 13 to be poured into the caisson 10 from a tank 41 is connected to, for example, the mobile hoisting mechanism 17 of the gantry crane 15, and is thereby suspended from the beam 15C of the gantry crane 15. This allows the position of the tip of the distributor 42 to be adjusted to any position in the X-direction by moving the gantry crane 15 in the X-direction, and also allows the position to be adjusted to any position in the Y-direction by moving the mobile hoisting mechanism 17 on the beam 15C in the Y-direction. A hose 43 is connected to the tip of the distributor 42 and hangs down.

[0087] As shown in Figure 16, in the seventh stage, a worker P standing on scaffolding 44 installed at the upper ends of compartments 10A-10D where filling work has been completed operates a hose 43 hanging from beam 15C of gantry crane 15 to pour concrete 13 from hose 43 into the upper ends of compartments 10A-10D to cast concrete covers. Figure 16 illustrates a state in which concrete covers 14A and 14B have been cast for two of the four compartments, 10A and 10B, on the Y positive side, and a worker P standing on scaffolding 44 is pouring concrete 13 in compartment 10C. The seventh stage of concrete cover casting work continues until covers have been cast for all compartments 10A-10D.

[0088] When the seventh stage of the cover casting work is completed, the distributor 42 is removed from the gantry crane 15, and the mixer vessel 40 moves away from the barge 2. Thereafter, as in the fifth stage of the first embodiment described with reference to FIG. 6, the curtain 8 is folded toward the bottom of the vessel, and the water stored in the water injection section 7 in the third stage of FIG. 12 is discharged outside the hull. As a result, as shown by arrow E in FIG. 6(A), the draft of the barge 2 decreases and rises relative to the water surface 23. Then, as shown by arrow F in FIGS. 6(A) and (B), the barge 2 moves in the negative X direction, and moves away from the existing caisson 20 and the newly installed caisson 10, completing the caisson installation work of the second embodiment.

[0089] In addition, the sixth stage of filling work described with reference to Figure 15B and the seventh stage of pouring the lid described with reference to Figure 16 may be configured in the same way as in Figures 7 and 8 of the first embodiment, where the barge 2 is separated from the caisson 10 and performed only by the soil transport vessel 30 or the mixer vessel 40 without using the gantry crane 15 of the barge 2.

[0090] In the caisson installation system 1A of the second embodiment, a configuration including a gantry crane 15 is illustrated as an example of a mobile unit that can move the caisson 10 housed in the flat water section 5 in the fore-and-aft direction of the barge 2, but elements other than the gantry crane 15 may be used as long as they can function as a mobile unit. For example, a configuration in which a set of winding devices such as winches is installed at each of the bow and stern ends of the flat water section 5 is exemplified. In this configuration, the ends of the wires wound and unwound by each winding device are connected to the caisson 10 from the bow and stern, respectively. Then, by combining the winding and unwound operations of the winding device set, the caisson 10 can be moved in the X direction within the flat water section 5.

[0091] The configurations of the caisson installation system 1 of the first embodiment and the caisson installation system 1A of the second embodiment can be applied to applications other than the installation of the caisson 10. For example, they can also be applied to the installation of concrete blocks underwater during revetment construction work, etc. In this case, concrete blocks are fixed to the flat water portion 5 of the barge 2.

[0092] In the first and second embodiments, a continuous caisson installation work for installing multiple caissons has been described as an example of caisson installation work, but the present invention is not limited to this. For example, the present invention can also be applied to a single caisson installation work (island installation) for installing one caisson 10 at a predetermined installation position on the seabed.

[0093] [Third embodiment] The third embodiment will be described with reference to Figures 17 to 20. The configuration of the caisson installation system 1A of the second embodiment can also be applied to dredging work.

[0094] Dredging work refers to the work of removing sediment from the bottom of the water. Dredging work includes dredging channels to ensure the width and depth for safe navigation of ships, dredging berths to ensure safe anchorage for ships, collecting sediment from the bottom of the water for land reclamation to be used in land development, and excavating the bottom to remove unsuitable soil for building the foundations of structures. It also includes collecting sediment for purposes such as covering, filling, and beach nourishment.

[0095] In recent years, dredgers have been mainly used for dredging work. Dredgers, for example, have a crane on board. The crane has a rotating body that is driven to rotate around a vertical axis of rotation, and a longitudinal boom that is rotatable around a horizontal axis of rotation is connected to the rotating body. A wire is arranged along the longitudinal direction of the boom on the crane, and one end is wound around a hoisting device such as a winch installed, for example, at the base end of the boom. The wire hangs down from the tip of the boom, and a grab bucket is attached to the lower end of the wire. The grab bucket is raised and lowered by unwinding or rewinding the wire using the hoisting device. The grab bucket can be moved to any position around the rotation axis of the rotating body by rotating the rotating body of the crane and rotating the boom.

[0096] In dredging work using a dredger, the dredger floating on the water is secured to the bottom of the water, and a crane on the ship moves the grab bucket to the desired position. The grab bucket is then lowered to the bottom of the water, where it excavates and grabs the sediment from the bottom. The grab bucket containing the collected sediment is then raised to the surface of the water, and a crane moves the grab bucket to a position directly above the soil transport ship. The grab bucket is then opened, and the collected sediment is loaded onto the soil transport ship. Such conventional dredging work is described, for example, in JP 2020-002775 A.

[0097] In conventional dredging operations using dredgers, the dredger and grab bucket can be affected by waves. For example, if the vertical movement of the dredger due to waves exceeds the operational limit, resulting in periods when work cannot be performed, the efficiency of dredging operations can decrease. Furthermore, if work is performed while the dredger is rocking due to the effects of waves, the safety of dredging operations can be reduced. Furthermore, if work is performed while the dredger is rocking, the accuracy of the crane's positioning of the grab bucket can decrease, resulting in a shift in the dredging position or a difference in the desired depth of the grab bucket's excavation of sediment at the bottom of the water, which can reduce the accuracy of dredging operations.

[0098] The third embodiment aims to provide a dredging system 1B that can reduce the influence of waves on dredging work.

[0099] FIG. 17 is a diagram showing the schematic configuration of a dredging system 1B according to a third embodiment. The schematics of FIGS. 17(A), (B), and (C) are similar to those of FIGS. 9(A), (B), and (C), respectively. The dredging system 1B of the third embodiment applies the basic configuration of the caisson installation system 1A of the second embodiment to main section work. As shown in FIGS. 17(A) to (C), the dredging system 1B of the third embodiment includes a barge 2, a thruster 3, a pair of longitudinal sections 4A and 4B, a flat water section 5, a connecting section 6, a gantry crane 15, a pair of guide sections 16A and 16B, and a mobile hoisting mechanism 17, similar to the caisson installation system 1A of the second embodiment.

[0100] Furthermore, in the dredging system 1B of the third embodiment, the filling bucket 18 of the caisson installation system 1A of the second embodiment can be used as the "dredging bucket 26." Therefore, the dredging bucket 26 can also be suspended from the beam 15C of the gantry crane 15 via the mobile hoisting mechanism 17 and moved along the beam 15C. Similarly, the beam 15C extends to the outside in the width direction of the barge 2, and the dredging bucket 26 can be moved to the outside of the barge 2 in the width direction via the mobile hoisting mechanism 17.

[0101] The dredging bucket 26 may be provided by a device separate from the filling bucket 18. In this case, a device separate from the moving hoisting mechanism 17 may also be used to operate the vertical and horizontal movement of the dredging bucket 26.

[0102] 17 illustrates a dredging system 1B of the third embodiment, similar to the caisson installation system 1A of the second embodiment, which includes a water injection unit 7 and a curtain 8. In this configuration, when dredging is performed in the flat water section 5, the barge 2 is lowered relative to the water surface 23 by the water injection unit 7 until the lower end of the curtain 8 contacts the water bottom 21, thereby enclosing the underwater area where dredging is performed. This prevents sediments on the water bottom 21, such as soil and mud, that are dispersed in the water during dredging in the flat water section 5 from leaking outside the barge 2, thereby preventing the water area around the barge 2 from becoming polluted due to dredging. However, the dredging system 1B may be configured without the water injection unit 7 and the curtain 8.

[0103] As shown in FIG. 17(B), the dredging system 1B of the third embodiment further includes a sealing unit 24 that closes the opening of the flat water section 5 on the stern side of the barge 2. The sealing unit 24 is composed of a foldable element, for example, similar to the curtain 8. In this configuration, for example, when the barge 2 is moving, the sealing unit 24 is installed in a folded state on one side of the pair of longitudinal units 4A, 4B. Then, when dredging work is performed, the sealing unit 24 is unfolded from the folded state and placed between the respective tips of the pair of longitudinal units 4A, 4B, thereby closing the opening of the flat water section 5.

[0104] Alternatively, the sealing portion 24 may be, for example, a plate-like member having a main surface in the front-to-rear direction (X direction) of the barge 2. In this case, the plate-like member serving as the sealing portion 24 may be configured to be fixedly installed at the tip end of each of the pair of longitudinal portions 4A, 4B, or may be configured such that a rotation axis along the vertical direction is provided on at least one of the pair of longitudinal portions 4A, 4B and the opening of the flat water portion 5 can be opened and closed by rotating around the rotation axis.

[0105] The dredging system 1B of the third embodiment includes a barge 2, a flat water section 5 formed by a depression from the rear end of the barge to the front, a thruster 3 as an example of a propulsion section that moves the barge 2 in any horizontal direction, a gantry crane 15 as a moving section that can move in the fore-and-aft direction of the barge 2 on the flat water section 5, and a dredging bucket 26 that is suspended from a beam 15C of the gantry crane 15 and can move along the beam 15C. The beam 15C extends to the outside in the width direction of the barge 2, and the dredging bucket 26 can move to the outside of the barge 2 in the width direction.

[0106] This configuration makes it possible to move dredging bucket 26 along the extension direction (Y direction) of beam 15C of gantry crane 15 between a position within flat water section 5 and a position outside barge 2. As a result, for example, if soil transport barge 50 (see Figure 18) is moored alongside barge 2, soil collected by dredging work within flat water section 5 using dredging bucket 26 can be easily loaded onto soil transport barge 50 by moving dredging bucket 26 with the soil grabbed to just above soil transport barge 50, thereby making dredging work more efficient.

[0107] Furthermore, if dredging is performed using the dredging bucket 26 in the flat water section 5 surrounded by the hull of the barge 2, the hull of the barge 2 can prevent waves generated outside the barge 2 from reaching the dredging bucket 26 and the area of ​​the flat water section 5 around the dredging bucket 26. This suppresses the up and down movement of the water surface 23 around the area where the dredging bucket 26 is located, preventing unexpected rocking of the dredging bucket 26 and allowing for more stable dredging work using the dredging bucket 26. As a result, the dredging system 1B of the third embodiment can reduce the impact of waves on dredging work. This effect is more pronounced when the barge 2 has a water injection section 7 and is configured to be able to sink.

[0108] The dredging system 1B of the third embodiment also includes a sealing section 24 that closes the opening of the flat water section 5 on the rear side of the barge 2. This configuration allows the flat water section 5 to be completely enclosed by the hull of the barge 2 and the sealing section 24, preventing waves from the stern from reaching the flat water section 5 through the opening. This further reduces the impact of waves on dredging operations. Furthermore, since the flat water section 5 can be completely enclosed by the hull of the barge 2 and the sealing section 24, sediments on the water bottom 21, such as soil and mud, which are dispersed in the water during dredging operations in the flat water section 5, can be prevented from leaking outside the barge 2, thereby preventing pollution of the waters around the barge 2 due to dredging operations.

[0109] Next, the procedure of the dredging operation by the dredging system 1B of the third embodiment will be described with reference to FIGS.

[0110] Fig. 18 is a diagram showing the first stage of dredging work in the third embodiment. Fig. 18 shows the barge 2 of the dredging system 1B in a plan view. Fig. 18 also illustrates a case where the dredging area 25 where the dredging work is carried out is set to a rectangular shape with opposite sides arranged along the X and Y directions. As shown in Fig. 18, it is preferable that the total area of ​​the dredging area 25 is several times larger than the area of ​​the barge 2 in a plan view.

[0111] In the example of Fig. 18, a first area 25A in which the first dredging work is to be performed within the dredging area 25 is set in the lower right corner of the rectangular shape of the dredging area 25. In Fig. 18, the range of the first area 25A is shown by a dotted line.

[0112] As shown in Figure 18, in the first stage, the barge 2 of the dredging system 1B moves into the first area 25A, and the barge 2 is fixed to the water bottom 21 by a plurality of anchors 11, etc., in the same manner as described with reference to Figure 3, etc. In this case, in the example of Figure 18, the stern side of the barge 2 is positioned on the X positive direction side, and the bow side is positioned on the X negative direction side, but the orientation of the barge 2 may be in the opposite direction.

[0113] Also, in the first stage, the soil transport barge 50 is brought alongside the barge 2 positioned in the first area 25A.

[0114] Then, as shown by arrow K in Figure 18, the gantry crane 15 moves from the bow to the stern of the barge 2. As a result, the dredging bucket 26 suspended from the gantry crane 15 also moves in the X direction above the flat water section 5 in conjunction with the movement of the gantry crane 15. In Figure 18, the gantry crane 15 at the initial position for dredging work in the first area 25A is shown by a dotted line, and the gantry crane 15 at the final position is shown by a solid line.

[0115] The gantry crane 15 stops sequentially at positions at approximately equal intervals along the X direction of the flat water section 5. At each of these stopping positions, the dredging bucket 26 is stopped at each position at approximately equal intervals along the width direction (Y direction) of the flat water section 5 by the mobile hoisting mechanism 17, lowered to the water bottom 21 to grab sediment from the water bottom 21, and then moved to the end of the beam 15C on the positive Y direction side each time to drop the grabbed sediment into the soil transport barge 50. This operation is performed at each position at approximately equal intervals along the width direction (Y direction) of the flat water section 5. When the dredging operation at each of these positions in the Y direction is completed at a predetermined position in the X direction, the dredging bucket 26 moves to the next position in the X direction and again performs dredging at each position in the Y direction at the new position. By performing these operations at each position in the X direction of the flat water portion 5, the bottom 21 of the flat water portion 5 is dredged over the entire area, and the dredging work in the first area 25A is completed.

[0116] It is preferable that the interval between the stopping positions of the gantry crane 15 in the X direction be equal to the X direction dimension of the area where the dredging bucket 26 can grab sediment from the water bottom 21. This allows dredging work to be carried out without gaps along the X direction at any Y direction position in the flat water section 5. Similarly, it is preferable that the interval between the stopping positions of the mobile hoisting mechanism 17 in the Y direction be equal to the Y direction dimension of the area where the dredging bucket 26 can grab sediment from the water bottom 21. This allows dredging work to be carried out without gaps along the Y direction at any X direction position in the flat water section 5.

[0117] 19 is a diagram showing a second stage of dredging work in the third embodiment. The outline of FIG. 19 is similar to that of FIG.

[0118] As shown in Figure 19, in the second stage, the barge 2 of the dredging system 1B moves to the second area 25B adjacent to the first area 25A, and the barge 2 is fixed to the waterbed 21 by a plurality of anchors 11, etc., as described with reference to Figure 3, etc.

[0119] In the example of Figure 19, the second area 25B where the second dredging work will be performed within the dredging area 25 is set in the lower left corner of the rectangle of the dredging area 25. In Figure 19, the extent of the second area 25B is shown by a dotted line. Also, the first area 25A where the dredging work has been completed is hatched.

[0120] Also in the second stage, the soil transport barge 50 is docked alongside the barge 2 positioned in the second area 25B.

[0121] 19, the gantry crane 15 moves from the bow to the stern of the barge 2. As a result, the dredging bucket 26 suspended from the gantry crane 15 also moves in the X direction over the flat water section 5 in conjunction with the movement of the gantry crane 15. As in the first stage, dredging operations are repeated at each position in the X direction and each position in the Y direction until the entire flat water section 5 is dredged from the water bottom 21, and the dredging work in the second area 25B is completed.

[0122] 20 is a diagram showing a third stage of dredging work in the third embodiment. The outline of FIG. 20 is similar to that of FIG.

[0123] As shown in Figure 20, in the third stage, dredging work similar to that in the first and second stages is completed from the third area 25C to the ninth area 25I, and then the work moves to the final tenth area 25J, where the barge 2 is fixed to the bottom 21 by multiple anchors 11, etc., as described with reference to Figure 3, etc.

[0124] In the example of Figure 20, the tenth area 25J, where the final (tenth) dredging work will be performed among the dredging areas 25, is set in the upper right corner of the rectangular shape of the dredging area 25. In Figure 20, the extent of the tenth area 25J is shown by a dotted line. In addition, the first area 25A to the ninth area 25I, where dredging work has been completed, are hatched.

[0125] Also, in the third stage, the soil transport barge 50 is docked alongside the barge 2 positioned in the tenth area 25J.

[0126] Then, as shown by arrow K in Figure 20, the gantry crane 15 moves from the bow to the stern of the barge 2. As a result, the dredging bucket 26 suspended from the gantry crane 15 also moves in the X direction over the flat water section 5 as the gantry crane 15 moves. As in the first and second stages, dredging operations are repeated at each position in the X direction and each position in the Y direction until the water bottom 21 is dredged over the entire flat water section 5, and dredging work in the tenth area 25J is completed. As a result, dredging work is completed over the entire dredging area 25.

[0127] In the dredging system 1B of the third embodiment, a configuration in which dredging work is performed using the dredging bucket 26 installed on the gantry crane 15 has been exemplified, but any configuration using elements other than buckets is also acceptable as long as dredging work can be performed in the flat water area 5. For example, a configuration may be provided in which a dredging pump is suspended from the beam 15C of the gantry crane 15. In this case, the lower end of the dredging pump is lowered to the position of the water bottom 21, and sediment is sucked from the water bottom 21 and discharged into the soil transport barge 50.

[0128] The dredging system 1B of the third embodiment may be configured to perform dredging work by utilizing the caisson installation system 1A of the second embodiment. In this case, it is preferable to add a sealing unit 24 to the caisson installation system 1A of the second embodiment.

[0129] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise. [Explanation of symbols]

[0130] 1. 1A Caisson Installation System 1B Dredging System 2 barges 3. Thruster (propulsion section) 4A, 4B Pair of long parts 5 Flat water part 6 Connecting part 7 Water injection part (descending part) 8 Curtain (covering part) 9 Rope (fixed part) 10 Caisson 12 Sand 13 Concrete 15 Gantry crane (moving part) 15C Beam section 18 Filling bucket 20, 20A, 20B, 20C Existing caissons 21 Underwater 22 Mound 23 Water surface 24 Sealing part 25 Dredging Area 26 Dredging Bucket 30, 30A Sediment Carrier 40 Mixer Ship 42 Distributor 50 Soil Carrier

Claims

1. Barge and A flat water section formed by recessing from the rear end of the barge along the front with a size capable of accommodating a caisson; A fixing portion that fixes the caisson in the flat water portion; a propulsion unit that propels the barge in any horizontal direction; A caisson installation system comprising:

2. A lowering section is provided for lowering the barge to a maximum draft when the caisson is installed. The caisson installation system of claim 1 .

3. A covering part is provided to cover the gap between the bottom of the barge and the bottom of the water when the caisson is installed.

3. A caisson installation system according to claim 1 or 2.

4. a connecting section for connecting rear sections of a pair of longitudinal sections extending in the fore-and-aft direction of the barge across the flat water section, The connecting portion is provided on the barge and is formed at a height that allows the caisson to pass through. The caisson installation system of claim 1 .

5. A moving unit is provided that can move the caisson housed in the flat water section in the fore-and-aft direction of the barge. The caisson installation system of claim 1 .

6. the moving unit is a gantry crane, a filling bucket suspended from a beam of the gantry crane and movable along the beam, the beam portion extends to the outer side of the barge in the width direction, and the filling bucket is movable to the outer side of the barge in the width direction.

6. The caisson installation system of claim 5.

7. the moving unit is a gantry crane, A distributor is provided which is suspended from the beam of the gantry crane and which dispenses concrete for pouring into the caisson.

6. The caisson installation system of claim 5.

8. the moving unit is a gantry crane, A dredging bucket is provided which is suspended from a beam of the gantry crane and is movable along the beam, The beam portion extends to the outside of the barge in the width direction, and the dredging bucket is movable to the outside of the barge in the width direction.

6. The caisson installation system of claim 5.

9. the moving unit is a gantry crane, A dredging pump is provided which is suspended from the beam of the gantry crane.

6. The caisson installation system of claim 5.

10. A sealing portion is provided to close the front opening of the flat water portion.

10. A caisson installation system according to claim 8 or 9.

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