Excavation and removal device for lower part of caisson cutting edge

Abstract

To provide an excavation and removal device for a lower part of a caisson cutting edge, capable of preventing over-digging during sinking work or bed setting and reliably discharging earth and sand and slime from the lower part of a caisson cutting edge.SOLUTION: As an example, an excavation and removal device 1 is configured such that nozzles 21a to 24a of multiple jet injection pipes 21 to 24 are arranged so that the injection direction from the nozzles 21a to 24a is above the horizontal direction, and tips of abutment plates 26 to 29 are arranged so that they protrude at least toward a lower part of a cutting edge from the nozzles 21a to 24a, and the excavated soil and sand below the cutting edge and slime accumulated below the cutting edge are sucked in through a suction port 25a of a suction pipe 25 by the injection from the nozzles 21a to 24a.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a device for excavating and removing the lower part of a caisson blade at the time of floor installation, for example, in the open caisson method.

Background Art

[0002] Generally, in the open caisson method, in order to excavate the earth and sand adhering to the lower part of the caisson blade, it is not possible to directly excavate from directly above. Especially in the case of soil with high adhesiveness, there may be cases where excavation remains. Therefore, conventionally, water jet injection by a diver has been used to break down the earth and sand at the lower part of the blade. However, in this case, reliable excavation, earth removal construction, and confirmation up to the tip part of the lower part of the blade cannot be performed. Especially in the case of soil with high adhesiveness and deep depth, it is not possible to remove the earth and sand neatly, and there was a possibility that excavation remains would occur.

[0003] In addition, although the slime (soft mud and sludge) deposited on the blade part and the bottom plate part is discharged by a slime cleaner (submersible sand pump), in this case, it is inefficient because a large amount of shaft water lighter than the slime is discharged. And when over-excavation occurs during floor installation, the earth and sand and slime that are broken down may accumulate at that location.

[0004] When placing the bottom slab concrete in such a state, the bottom slab strength is insufficient, and it also causes water leakage, leading to a deterioration in the quality of the entire structure. In addition, over-excavation during the sinking operation may induce excessive settlement, inclination, and eccentricity, and may affect the construction of the caisson body of the next lot, or may become a quality control problem such as the sinking accuracy of the caisson body.

[0005] Conventionally, as a technique for peeling off the deposits on the blade of an open caisson with water flow, sucking them in with a pump, and discharging them, there is an underwater deposit removing device described in Patent Document 1.

[0006] In addition, as a technique for removing excavation remains at the lower part of the blade of an open caisson by jet injection, there is a construction method of an open caisson described in Patent Document 2.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in the underwater deposit removing device described in Patent Document 1, there is no problem as long as the sediment thinly adheres to the blade edge. However, when clay or the like having adhesiveness adheres, the deposit cannot be removed only by the discharge force of the pump, and it is necessary to assist by manually breaking it up or the like.

[0009] In addition, in the construction method of the open caisson described in Patent Document 2, the pressurized water jetted from the water jet injection pipe may be jetted below the horizontal level. In this case, there is a possibility of over-excavation down to below the blade tip. Also, in a high water pressure environment, if the loosened slurry is not immediately recovered, the removed sediment may re-consolidate.

[0010] The present invention has been made in consideration of the above circumstances, and an object thereof is to provide an excavation and removal device for the lower part of a caisson blade that can prevent over-excavation during the sinking operation or when landing on the floor, and can surely discharge the sediment and slime at the lower part of the caisson blade.

Means for Solving the Problems

[0011] In order to solve the above problems, the invention according to claim 1 of the present invention is an excavation and soil discharge device at the lower part of a caisson blade, which excavates and discharges the soil and sand at the lower part of the blade of the caisson during the sinking operation of the caisson or when the caisson is sunk to a predetermined depth and has a floor, and is provided with a high-pressure pipe arranged from a ground pressure feeding pump to the vicinity of the lower part of the blade and through which high-pressure water is fed, at least one jet injection pipe connected to the high-pressure pipe and jet injecting the high-pressure water from an injection port toward the soil and sand at the lower part of the blade, and a contact plate arranged below the jet injection pipe and contacting the bottom plate part of the caisson. The injection port is provided such that the injection direction from the injection port of the jet injection pipe is above the horizontal direction, and the tip of the contact plate is provided so as to protrude at least toward the lower part of the blade from the injection port. It is characterized in that the excavated soil and sand at the lower part of the blade and the slime deposited on the lower part of the blade are configured to be sucked from a suction pipe by the injection of the injection port.

[0012] Further, the invention according to claim 2 of the present invention is characterized in that, in addition to the configuration according to claim 1, the suction pipe is arranged in parallel with the jet injection pipe, and the injection port and the suction port of the suction pipe are arranged in the vicinity of each other.

[0013] Further, the invention according to claim 3 of the present invention is characterized in that, in addition to the configuration according to claim 1, a plurality of jet injection pipes are arranged, and the angle formed with the horizontal direction of injection from the injection port of any one of these jet injection pipes is set to be different from the angle formed with the horizontal direction of injection from the injection port of another jet injection pipe.

[0014] Further, the invention according to claim 4 of the present invention is characterized in that, in addition to the configuration according to claim 1, a suction pump is installed in the device main body, and by driving the suction pump, the excavated soil and sand at the lower part of the blade and the slime deposited on the lower part of the blade are sucked by the suction pump through the suction pipe, and the slime below the bottom plate part of the caisson is sucked from the suction port of the suction pump and discharged to the outside of the caisson.

[0015] Further, the invention according to claim 5 of the present invention is characterized in that, in addition to the configuration according to claim 4, the upper part and the side part of the suction port of the suction pump are respectively surrounded by an upper surface plate and a side surface plate.

Advantages of the Invention

[0016] According to the invention described in claim 1 of the present invention, the injection port is provided such that the injection direction from the injection port of at least one jet injection pipe is above the horizontal direction, and the tip of the contact plate is provided so as to protrude at least to the lower side of the blade edge from the injection port. Since it is configured to suck the excavated earth and sand at the lower part of the blade edge and the slime deposited at the lower part of the blade edge from the suction port of the suction pipe by the injection from the injection port, overexcavation during the sinking operation or when attaching to the floor can be prevented, and the earth and sand and slime at the lower part of the caisson blade edge can be reliably discharged.

[0017] Further, according to the invention described in claim 2 of the present invention, in addition to the effect of the invention described in claim 1, since the suction pipe is arranged in parallel with the jet injection pipe and the injection port and the suction port of the suction pipe are arranged in the vicinity of each other, the excavated earth and sand at the lower part of the blade edge can be reliably sucked from the suction port of the suction pipe by the injection from the injection port.

[0018] Further, according to the invention described in claim 3 of the present invention, in addition to the effect described in claim 1, since the angle formed with the horizontal direction of injection from the injection port of any jet injection pipe and the angle formed with the horizontal direction of injection from the injection port of another jet injection pipe are set to be different, it becomes easier to collapse the earth and sand at the lower part of the caisson blade edge, and the working efficiency of collapsing the earth and sand can be improved at each stage.

[0019] Further, according to the invention described in claim 4 of the present invention, in addition to the effects of the invention described in claim 1, by driving the suction pump, the excavated earth and sand below the cutting edge and the slime deposited below the cutting edge are sucked into the suction pump through the suction pipe, and the slime below the bottom plate of the caisson is sucked from the suction port of the suction pump and discharged to the outside of the caisson. Therefore, it is possible to reliably and easily discharge the earth and sand and slime below the cutting edge and the slime below the bottom plate to the outside of the caisson.

[0020] Further, according to the invention described in claim 5 of the present invention, in addition to the effects of the invention described in claim 4, since the upper part and the side part of the suction port of the suction pump are respectively surrounded by the upper surface plate and the side surface plate, it is possible to reliably suck the slime deposited below the cutting edge from the suction port of the suction pipe with little suction of the shaft pit water, and to reliably suck the slime below the bottom plate of the caisson from the suction port of the suction pump. As a result, it is possible to effectively discharge the slime to the outside of the caisson.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiment for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0023] [One Embodiment] FIG. 1 is a configuration diagram showing the sinking state of an excavation and removal device at the lower part of a caisson blade according to one embodiment of the present invention. FIG. 2 is a configuration diagram showing a state in which the inside of the caisson body is excavated to the floor height with a clam shell bucket before excavating the lower part of the caisson blade with the excavation and removal device of FIG. 1. FIG. 3 is a schematic plan view showing the excavation and removal device at the lower part of the caisson blade of FIG. 1. FIG. 4 is a schematic front view showing the excavation and removal device at the lower part of the caisson blade of FIG. 1. FIG. 5 is an enlarged view showing the structure of the jet injection pipe, the contact plate, and the vicinity of the suction port of the excavation and removal device at the lower part of the caisson blade of FIG. 4. FIG. 6 is an enlarged side view showing the jet injection pipe and the injection port of FIG. 4. FIG. 7 is an enlarged side view showing the suction pipe and the suction pump of FIG. 1.

[0024] Note that the excavation and removal device 1 at the lower part of the caisson blade as the device main body in this embodiment (hereinafter simply referred to as the excavation and removal device) is used for the construction of the open caisson method. This open caisson method is a method in which the inside of a cylindrical caisson body with open upper and lower surfaces is gradually sunk while excavating and discharging soil from the ground with an excavating machine such as a clam shell bucket.

[0025] Also, in the excavation and removal device 1 of the present embodiment below, an example will be described in which, when the caisson body is sunk to the floor with a predetermined depth as described above, the soil and sand at the lower part of the blade of the caisson body are excavated and this soil and sand are discharged together with the slime. Here, the present invention is applicable not only when the caisson body is sunk to the floor with a predetermined depth, but also during the sinking operation of the caisson body.

[0026] As shown in FIGS. 1 and 2, in the excavation and removal device 1, the caisson body 2 is sunk to a predetermined depth in water, and its cutting edge 3 has a tapered surface 3a which is an inclined surface that slopes from the inner circumferential surface to the outer circumferential surface at the lower part of the caisson body 2. The bottom plate part (inner bottom part) 8 in the caisson body 2 is constructed to the predetermined depth as shown in FIG. 1 by repeatedly performing excavation and soil removal operations by operating the clam shell bucket 5 from the ground 4 as shown in FIG. 2. The clam shell bucket 5 is suspended and supported in the shaft 9 by a crawler crane 7 as a hoisting means installed on the ground via a wire 6 which is a cable body.

[0027] As described above, with only the excavation and soil removal operations by the clam shell bucket 5, not only is there remaining soil and sand left at the lower part of the cutting edge 3, but also highly viscous soil and sand adheres to the tapered surface 3a and slime is deposited.

[0028] The excavation and removal device 1 of the present embodiment places underwater concrete on the bottom plate part 8 of the caisson body 2 to construct a bottom plate concrete layer, so as to remove the remaining soil and sand and deposited slime at the lower part of the cutting edge 3, and also to remove the highly viscous soil and sand adhering to the tapered surface 3a and level the surface. In FIG. 1, this leveling height is indicated by H. By doing so, it is possible to avoid the causes of insufficient bottom plate strength and water seepage when constructing the bottom plate concrete layer, and to prevent a decline in the quality of the entire structure.

[0029] The excavation and removal device 1 is installed near the lower part of the cutting edge 3. The excavation and removal device 1 has a gantry 10, and this gantry 10 is configured by combining, for example, L-shaped steels in a three-dimensional shape and joining them to each other by fixing means such as welding. Note that the gantry 10 is not limited to the shape shown in FIG. 1 and can be any shape as long as it can maintain stability when installed on the bottom plate part 8 in the caisson body 2.

[0030] As shown in FIG. 1, in the state where the excavation and removal device 1 is installed on the chassis portion 8, a jet injection unit 20 is disposed on the lower side of the cutting edge 3 of the gantry 10. This jet injection unit 20 is connected to a high-pressure pipe 11. This high-pressure pipe 11 is arranged from the pressure pump 12 installed on the ground 4 to the vicinity of the lower part of the cutting edge 3, and high-pressure water is fed into the jet injection unit 20 through the high-pressure pipe 11 by driving the pressure pump 12.

[0031] In the state where the excavation and removal device 1 is installed on the chassis portion 8, a weight 13 is arranged on the side opposite to the lower side of the cutting edge 3 of the gantry 10. This weight 13 has a weight sufficient to withstand the reaction force even when high-pressure water is jet-injected J toward the sediment at the lower part of the cutting edge 3 by the jet injection unit 20.

[0032] A slime cleaner (submersible sand pump) 14 as a suction pump is installed at the central portion of the gantry 10. This slime cleaner 14 is provided with a suction port 14a on the bottom surface side, while a discharge port 14b is provided at a substantially intermediate portion in the vertical direction. One end of a sludge discharge pipe 15 is connected to this discharge port 14b, and the other end of this sludge discharge pipe 15 extends to the ground 4 through the caisson body 2. Note that the slime cleaner 14 incorporates, for example, a hydraulic motor with an accumulator and has a powerful and stable sludge discharge function. Although the slime cleaner 14 incorporates a hydraulic motor with an accumulator as a driving means, it is not limited thereto, and other driving means having a powerful and stable sludge discharge function may be incorporated.

[0033] As shown in FIGS. 3 to 6, the jet injection section 20 is provided with a plurality (four in this embodiment) of jet injection pipes 21 to 24 arranged in parallel with each other. These jet injection pipes 21 to 24 are each provided with injection ports 21a to 24a at their tip ends. High-pressure water is configured to be jet-injected J from these injection ports 21a to 24a toward the earth and sand ES below the cutting edge 3. In this embodiment, the jet injection pipes 21 to 24 are provided in two sets, with two left and right jet injection pipes 21 and 22 and two jet injection pipes 23 and 24 as one set each. A suction pipe 25 is arranged between the two sets of jet injection pipes 21, 22 and the jet injection pipes 23, 24. This suction pipe 25 is arranged in parallel with the jet injection pipes 21 to 24. The suction pipe 25 is formed in a cylindrical shape and has a suction port 25a that is notched in a tapered shape at the lower side, and this suction port 25a is arranged in the vicinity of the injection ports 21a to 24a. The suction pipe 25 is provided so as to be in communication with the suction port 14a of the slime cleaner 14.

[0034] The suction pipe 25 is configured to suck in the excavated earth and sand ES below the cutting edge 3 and the slime S deposited below the cutting edge 3 by the high-pressure water jetted from the injection ports 21a to 24a through the suction port 25a. That is, while driving the slime cleaner 14 and driving the pressure feed pump 12 to jet-inject J the high-pressure water from the injection ports 21a to 24a of the jet injection pipes 21 to 24 toward the earth and sand ES below the cutting edge 3 to collapse the earth and sand ES below the cutting edge 3, the collapsed earth and sand ES below the cutting edge 3 and the slime S deposited below the cutting edge 3 are sucked into the slime cleaner 14 through the suction pipe 25, and the slime S below the bottom plate portion 8 of the caisson body 2 is sucked in from the suction port 14a of the slime cleaner 14 and discharged to the outside of the caisson body 2 through the sludge discharge pipe 15 via its discharge port 14b.

[0035] Below the jet nozzles 21 to 24, contact plates 26 to 29 made of steel plates, each formed in an L-shaped cross-section, are arranged. These contact plates 26 to 29 are configured to contact the chassis portion 8 of the caisson body 2 in the installed state on the chassis portion 8 of the excavation removal device 1. These contact plates 26 to 29 extend to such lengths that their respective tip portions protrude at least to the lower side of the cutting edge 3 from the jet ports 21a to 24a. Also, the widths of the contact plates 26 to 29 are each formed wider than the diameters of the respective jet nozzles 21 to 24. Therefore, each of the jet nozzles 21 to 24 is adapted to fit inside the lengths and widths of the respective contact plates 26 to 29.

[0036] As shown in FIG. 6, the jet ports 21a and 22a of the jet nozzles 21 and 22 are set such that the angles formed with the horizontal direction of injection are different from each other. Similarly, the jet ports 23a and 24a of the jet nozzles 23 and 24 are also set such that the angles formed with the horizontal direction of injection are different from each other. Specifically, in the present embodiment, the angle α, that is, the upward angle α, formed by the jet ports 22a and 23a of the jet nozzles 22 and 23 with the horizontal direction is set to 1 degree, and the angle β, that is, the upward angle β, formed by the jet ports 21a and 24a of the jet nozzles 21 and 24 with the horizontal direction is set to 30 degrees.

[0037] The lower part of the slime cleaner 14 is surrounded by an iron plate-made surrounding member 30 formed in a rectangular box shape. Specifically, the surrounding member 30 includes a single rectangular top plate 31 with an open bottom surface and a cutout portion at the attachment portion of the suction port 14a of the slime cleaner 14, and four side plates 32 that extend downward from the four sides of this top plate 31. Thereby, the upper part and the side part of the suction port 14a of the slime cleaner 14 are configured to be surrounded by a single top plate 31 and the four side plates 32a to 32d.

[0038] One of the four side plates 32, i.e., side plate 32a, is fixed so that the jet injection pipes 21 to 24 and the suction pipe 25 penetrate therethrough. At the corner between the top plate 31 and the side plate 32a, the rear end portion of the protection member 35 is fixed by welding, while the front end portion thereof is fixed by welding near the tips of the contact plates 26 to 29. Thus, the protection member 35 is provided in an inclined manner between the corner of the top plate 31 and the side plate 32a and near the tips of the contact plates 26 to 29. The protection member 35 is formed in a U shape in plan view by an L-shaped metal fitting made of a steel plate having an L-shaped cross section.

[0039] The protection member 35 is formed such that its width is wider than the entire width of the contact plates 26 to 29 and its length extends to the vicinity of the injection ports 21a to 24a. By forming the protection member 35 in this way, it is possible to prevent the jet injection pipes 21 to 24 and the suction pipe 25 from colliding with other members and being damaged during the transfer of the excavation and removal device 1.

[0040] Next, the operation of the excavation and removal device at the lower part of the caisson blade according to the present embodiment will be described.

[0041] First, as shown in FIG. 2, the clamshell bucket 5 is operated from the ground 4 to repeatedly perform excavation and soil discharge operations, thereby excavating to the floor attachment height H.

[0042] Next, the excavation and removal device 1 according to the present embodiment is suspended, for example, by a crawler crane 7 and suspended into the shaft 9, and the chassis 8 is placed so that the jet injection unit 20 of the excavation and removal device 1 faces the lower part of the blade 3 of the caisson body 2.

[0043] Then, the slime cleaner 14 is driven to suck the slime S deposited at the lower part of the blade 3 from the suction pipe 25 and suck the slime S below the chassis 8 of the caisson body 2 from the suction port 14a, and discharge these slimes S to the outside through the sludge discharge pipe 15.

[0044] Furthermore, the pressure feed pump 12 is driven to perform jet injection J from the injection ports 21a to 24a of the jet injection pipes 21 to 24 through the high-pressure pipe 11 toward the earth and sand ES below the cutting edge 3. Thereby, the earth and sand ES below the cutting edge 3 is dug out. Here, the injection ports 21a and 22a of the jet injection pipes 21 and 22 are set such that the angles formed with the horizontal direction of injection are different from each other, and the injection ports 23a and 24a of the jet injection pipes 23 and 24 are also set such that the angles formed with the horizontal direction of injection are different from each other.

[0045] Specifically, the angle α formed by the injection port 22a and the injection port 23a with the horizontal direction, that is, the upward angle α is set to 1 degree, and the angle β formed by the injection port 21a and the injection port 24a with the horizontal direction, that is, the upward angle β is set to 30 degrees. Therefore, the jet flows jet-injected J from the injection port 21a and the injection port 24a respectively are injected into the earth and sand ES below the cutting edge 3 so as to intersect and merge. As a result, the injection amount into the earth and sand ES is doubled and it becomes easier to collapse, and the working efficiency of digging out the earth and sand ES below the cutting edge 3 can be improved at each stage.

[0046] When the excavation and removal device 1 reaches the depth of the floor-attached height H, the excavation and removal work is completed, and the entire excavation and removal device 1 is suspended and moved to the next construction location by, for example, a crawler crane 7.

[0047] In addition, in this embodiment, since the work of digging out the earth and sand ES below the cutting edge 3 by a diver is eliminated, the diving work can be significantly reduced, and the safety and workability can be improved.

[0048] Thus, according to this embodiment, the injection ports 21a to 24a of the plurality of jet injection pipes 21 to 24 are provided such that the injection directions from the injection ports 21a to 24a are above the horizontal direction, and the tip portions of the contact plates 26 to 29 are provided so as to protrude at least to the lower side of the cutting edge 3 from the injection ports 21a to 24a. The excavated earth and sand ES at the lower part of the cutting edge 3 and the slime S deposited at the lower part of the cutting edge 3 are configured to be sucked from the suction port 25a of the suction pipe 25 by the injection from the injection ports 21a to 24a. Therefore, overexcavation during floor installation can be prevented, and the earth and sand ES and slime S at the lower part of the cutting edge 3 can be reliably discharged. In this case, the same effect can be obtained not only when the caisson body 2 is sunk to a predetermined depth but also during the sinking operation of the caisson body 2.

[0049] Further, according to this embodiment, since the suction pipe 25 is arranged in parallel with the jet injection pipes 21 to 24, and the injection ports 21a to 24a and the suction port 25a of the suction pipe 25 are arranged in the vicinity of each other, the excavated earth and sand ES at the lower part of the cutting edge 3 can be reliably sucked from the suction port 25a of the suction pipe 25 by the injection from the injection ports 21a to 24a.

[0050] Further, according to this embodiment, since the angle α formed with the horizontal direction of the injection from the injection ports 21a and 23a of any of the jet injection pipes 21 and 23 and the angle β formed with the horizontal direction of the injection from the injection ports 22a and 24a of the other jet injection pipes 22 and 24 are set to be different, the earth and sand ES at the lower part of the cutting edge 3 can be easily collapsed, and the working efficiency of collapsing the earth and sand ES can be improved at each stage.

[0051] Further, according to this embodiment, by driving the slime cleaner 14, the excavated earth and sand ES at the lower part of the cutting edge 3 and the slime S deposited at the lower part of the cutting edge 3 are sucked by the slime cleaner 14 through the suction pipe 25, and the slime S below the bottom plate portion 8 is sucked from the suction port 14a of the slime cleaner 14 and discharged to the outside of the caisson body 2. Therefore, the earth and sand ES and slime S at the lower part of the cutting edge 3 and the slime S below the bottom plate portion 8 can be reliably and easily discharged to the outside of the caisson body 2.

[0052] Further, according to the present embodiment, since the upper and side portions of the suction port 14a of the slime cleaner 14 are surrounded by the upper surface plate 31 and the side surface plates 32a to 32d, respectively, the slime S deposited below the blade edge 3 can be surely sucked from the suction port 25a of the suction pipe 25 without sucking in almost the shaft pit water, and the slime S below the bottom plate portion 8 of the caisson body 2 can be surely sucked from the suction port 14a of the slime cleaner 14. As a result, the slime S can be effectively discharged to the outside of the caisson body 2.

[0053] Further, according to the present embodiment, by arranging the weight 13 on the excavation and removal device 1, in addition to the effect of being able to sufficiently withstand the reaction force even when high-pressure water is jet-injected J, the weight balance of the excavation and removal device 1 can be achieved, and a sealed space can be formed by pressing the lower ends of the side surface plates 32a to 32d of the excavation and removal device 1 against the slime S deposited on the bottom plate portion 8. Thereby, the slime S deposited on the bottom plate portion 8 can be surely and easily sucked in.

[0054] Further, according to the present embodiment, since the lower side of the suction port 25a of the suction pipe 25 is formed by being notched in a tapered shape, the earth and sand ES and the slime S below the blade edge 3 can be more surely sucked in without sucking in much shaft pit water.

[0055] [Other Embodiments of the Invention] Although one embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. This embodiment can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the gist of the invention. This embodiment is included in the scope and gist of the invention, and is also included in the invention described in the claims and the equivalent scope thereof.

[0056] In the above-described embodiment, an example was described in which the angles α formed by the injection ports 21a and 23a of the jet injection pipes 21 and 23 with the horizontal direction were set to 1 degree, and the angles β formed by the injection ports 22a and 24a of the jet injection pipes 22 and 24 with the horizontal direction were set to 30 degrees. However, the present invention is not limited to this, and by connecting the jet injection pipes 21 to 24 and the injection ports 21a to 24a with flexible joint pipes respectively, the injection angles of the injection ports 21a to 24a can be arbitrarily changed.

[0057] Here, since the injection angle of the jet injection J injected from the injection ports 21a to 24a that has the highest effect of knocking down the earth and sand ES varies depending on the shape of the tapered surface 3a at the lower part of the cutting edge 3 and the shape of the earth and sand ES, if the injection angles of the injection ports 21a to 24a are changed based on the shape of the tapered surface 3a at the lower part of the cutting edge 3 and the shape of the earth and sand ES, the working efficiency of knocking down the earth and sand ES can be improved at each stage.

[0058] In addition, in the above-described embodiment, an example was described in which two sets of left and right jet injection pipes 21 and 22 and jet injection pipes 23 and 24 in the jet injection pipes 21 to 24 were provided as one set each. However, the present invention is not limited to this, and more than two sets or a plurality of pipes may be arranged side by side in the horizontal direction, or a plurality of sets or a plurality of jet injection pipes may be arranged in multiple stages in the vertical direction. Furthermore, in the above-described embodiment, an example was described in which a plurality of (four) jet injection pipes 21 to 24 were provided. However, the present invention is not limited to this, and one pipe may be used, that is, at least one pipe may be provided.

[0059] Furthermore, pointed piercing rods for knocking down the earth and sand ES may be provided adjacent to the jet injection pipes 21 to 24 so as to protrude to the lower side of the cutting edge 3 from the injection ports 21a to 24a. By configuring in this way, while the earth and sand ES is pierced by the piercing rod, the effect of knocking down the earth and sand ES by the jet injection J of the jet injection pipes 21 to 24 can be further improved.

[0060] In the above-described embodiment, an example in which the overall shape of the caisson body 2 is formed in a circular container shape has been described. However, the present invention is not limited to this, and it may be formed in a rectangular container shape, an elliptical container shape, or a polygonal container shape.

Explanation of Signs

[0061] 1 Excavation and removal device 2 Caisson body 3 Cutting edge 3a Tapered surface 4 Ground 5 Clamshell bucket 6 Wire 7 Crawler crane 8 Chassis part 9 Shaft 10 Stand 11 High-pressure pipe 12 Pressure pump 13 Weight 14 Slime cleaner (suction pump) 14a Suction port 14b Discharge port 15 Sludge pipe 20 Jet injection part 21~24 Jet injection pipes 21a~24a Injection ports 25 Suction pipe 25a Suction inlet 26~29 Contact plate 30 Surrounding member 31 Top panel 32a~32d Side panels 35 Protection member ES Earth and sand H Height with floor S Slime J Jet injection

Claims

1. A device for excavating and removing sediment at the lower part of the caisson blade, which excavates and removes the sediment at the lower part of the blade of the caisson during the sinking operation of the caisson or when the caisson is sunk to a predetermined depth and has a floor, comprising: A high-pressure pipe arranged from a ground pumping pump to the vicinity of the lower part of the blade and into which high-pressure water is fed; At least one jet injection pipe connected to the high-pressure pipe and jet-injecting the high-pressure water from the injection port toward the sediment at the lower part of the blade; A contact plate arranged below the jet injection pipe and contacting the bottom plate part of the caisson; The injection port is provided such that the injection direction from the injection port of the jet injection pipe is above the horizontal direction, and the tip of the contact plate is provided so as to protrude at least toward the lower part of the blade from the injection port, and the sediment excavated at the lower part of the blade and the slime deposited on the lower part of the blade by the injection of the injection port are configured to be sucked from the suction port of the suction pipe. A device for excavating and removing sediment at the lower part of the caisson blade, characterized in that.

2. The suction pipe is arranged in parallel with the jet injection pipe, The device for excavating and removing sediment at the lower part of the caisson blade according to claim 1, characterized in that the injection port and the suction port of the suction pipe are arranged in the vicinity of each other.

3. A plurality of jet injection pipes are arranged, and the angle formed with the horizontal direction of injection from the injection port of any jet injection pipe among these jet injection pipes is set to be different from the angle formed with the horizontal direction of injection from the injection port of other jet injection pipes. The device for excavating and removing sediment at the lower part of the caisson blade according to claim 1, characterized in that.

4. A suction pump is installed in the device body, and by driving the suction pump, the sediment excavated at the lower part of the blade and the slime deposited on the lower part of the blade are sucked by the suction pump through the suction pipe, and the slime below the bottom plate part of the caisson is sucked from the suction port of the suction pump and discharged to the outside of the caisson. The device for excavating and removing sediment at the lower part of the caisson blade according to claim 1, characterized in that.

5. The device for excavating and removing sediment at the lower part of the caisson blade according to claim 4, characterized in that the upper part and the side part of the suction port of the suction pump are respectively surrounded by an upper surface plate and a side surface plate.

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