Method for removing foreign matter, and system for removing foreign matter from a rubble mound.

Abstract

To remove debris in a void of a rubble mound.SOLUTION: A casing 60 is inserted from a top end surface 30 of a rubble mound 3 to drill a hole A into the rubble mound 3. A suction tube 1 is inserted into the hole A drilled by the casing 60. A suction pump P1 sucks up debris in voids in the rubble mound 3 together with seawater via the suction pipe 1. An injection pipe 2 is installed adjacently to or inside the suction pipe 1. An injection pump P2 injects high-pressure water from a nozzle 20 via the injection pipe 2. A driving device 5 rotates the injection pipe 2 so that the nozzle 20 rotates in a circumferential direction around a central axis of the injection pipe 2. Further, the driving device 5 raises and lowers the injection pipe 2 along a longitudinal direction.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a method for sucking impurities and an impurity suction system in a rubble mound.

Background Art

[0002] In recent years, ships such as newly built container ships have tended to become larger. Along with the enlargement of ships, the cases of deepening the quay walls of existing mooring ports have been increasing. The gravity quay wall deepening method is a method that enables the deepening of a gravity quay wall without changing the normal position by injecting and solidifying a solidifying material such as a plastic grout into a part of an existing rubble mound.

[0003] On the other hand, in existing rubble mounds, a large amount of impurities such as sand, clay, and shells may exist in the voids between the rubble regardless of the length of the years after construction. When a large amount of impurities exist in the voids of the rubble mound, it is considered difficult to inject the solidifying material into the rubble mound. Also, for example, in order to inject a solidifying material into the voids of the rubble mound for deepening, it is assumed that the solidifying material is injected into 80% or more of the voids, and it is also considered necessary that the impurities are removed.

[0004] Therefore, prior to the injection of the solidifying material, the development of a method for removing impurities in the voids of the rubble mound is expected. This method is used not only as a pretreatment for the above-described deepening method but is also useful for seismic reinforcement of quay walls and revetments. Also, this method is useful even when the solidifying material is not injected into the voids from which the impurities have been removed. For example, this method can also be used to improve the water permeability of breakwaters, quay walls, etc. whose water permeability has decreased due to clogging of impurities in the voids of the rubble mound.

[0005] By the way, for dredging, removing the backfill material in a caisson, or removing the sediment in a foundation pile, etc., the use of an underwater object suction and conveyance device using compressed air has been considered (Patent Document 1).

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2006-348666 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] One of the objectives of the present invention is to provide a method for removing impurities from the voids of a rubble mound. [Means for solving the problem]

[0008] The method for sucking up foreign matter according to claim 1 of the present invention is for an existing rubble mound The casing is used to drill a hole, and the hole drilled by the casing This method involves inserting a suction tube and sucking up foreign matter from the voids in the rubble mound along with water through the opening at the tip of the suction tube.

[0009] The method for aspirating foreign matter according to claim 2 of the present invention is: A method for removing foreign matter, in which an existing rubble mound is drilled using a casing, the casing is placed in the drilled hole and used as a suction tube, and foreign matter in the voids of the rubble mound is sucked out along with water from the opening at the tip of the suction tube. That is the case.

[0010] The method for aspirating foreign matter according to claim 3 of the present invention, in the embodiment described in claim 1 or 2, In the rubble mound, an injection pipe equipped with a nozzle for spraying high-pressure water is installed adjacent to the opening of the suction pipe inserted into the suction pipe or inside the suction pipe, and when the suction pipe sucks up the foreign matter, high-pressure water is sprayed into the rubble mound from the nozzle. This is a method for aspirating foreign matter.

[0011] The method for aspirating foreign matter according to claim 4 of the present invention is, 1 or In the embodiment described in 2, A space is set up in which foreign matter is removed by the suction of the inserted suction tube, the suction tube is inserted so that the opening of the suction tube is positioned at a predetermined distance deeper than the bottom surface of the space, and the foreign matter is suctioned. This is a method for aspirating foreign matter.

[0012] The method for aspirating foreign matter according to claim 5 of the present invention is, 1 or 2 In the embodiment described above, the rubble mound on which a structure is placed directly above it, The aforementioned Avoiding structures, The aforementioned Inside the rubble mound The aforementioned The hole The aforementioned This is a method for removing foreign matter by drilling a hole with the casing so that it extends directly below the structure.

[0013] The method for aspirating foreign matter according to claim 6 of the present invention is, 3In the aspect described in The nozzle is rotated by the drive device so that it rotates circumferentially with respect to the central axis of the injection tube. it is an impurity suction method.

[0014] The impurity suction method according to claim 7 of the present invention is as described in claim 3 In the aspect described in The drive mechanism raises and lowers the injection pipe along its longitudinal direction. it is an impurity suction method.

[0015] The impurity suction method according to claim 8 of the present invention is as described in claim 3 In the aspect described in The removal range of the impurities is adjusted using at least one of the spray range, spray pressure, and spray volume of the high-pressure water. it is an impurity suction method.

[0016] The impurity suction method according to claim 9 of the present invention is as described in claim 3 In the aspect described in The proportion of impurities drawn in with the water through the suction tube is measured, and the amount of high-pressure water injected by the injection tube is adjusted based on the measured proportion. it is an impurity suction method.

[0017] The impurity suction method according to claim 10 of the present invention is as described in claim 9 In the aspect described in When the measured percentage falls below the threshold, suction by the suction tube is stopped. it is an impurity suction method.

[0018] The impurity suction method according to claim 11 of the present invention is as described in claim 1 or In the aspect described in claim 2 A storage tank is provided for storing the foreign matter sucked up by the suction pipe, and the suction by the suction pipe is stopped according to the weight of the foreign matter accumulated in the storage tank. it is an impurity suction method.

[0019] The one according to claim 12 of the present invention Suction system for removing foreign matter from rubble mounds is A system for removing debris from a rubble mound comprises: a casing that drills a hole in an existing rubble mound; a suction pipe inserted into the hole drilled by the casing; a spray pipe installed adjacent to or inside the suction pipe; a suction pump that sucks up debris from the voids of the rubble mound along with water via the suction pipe; a spray pump that sprays high-pressure water from the nozzle of the spray pipe via the spray pipe; a regulator that adjusts the suction force of the suction pump and the spray output of the spray pump; and a drive device that rotates the spray pipe so that the nozzle rotates circumferentially with respect to the central axis of the spray pipe. as follows.

[0020] The one according to claim 13 of the present invention Suction system for removing foreign matter from rubble mounds is A system for removing debris from a rubble mound comprises: a casing used as a suction pipe, which is placed in a hole formed by drilling a hole in an existing rubble mound; a spray pipe installed adjacent to or inside the suction pipe; a suction pump that sucks up debris from the voids of the rubble mound along with water via the suction pipe; a spray pump that sprays high-pressure water from the nozzle of the spray pipe via the spray pipe; a regulator that adjusts the suction force of the suction pump and the spray output of the spray pump; and a drive device that rotates the spray pipe so that the nozzle rotates circumferentially with respect to the central axis of the spray pipe. as follows.

Advantages of the Invention

[0022] According to the present invention, impurities in the voids of the slag mound can be removed.

Brief Description of the Drawings

[0023] [Figure 1] The figure showing an example of the suction pipe 1 that sucks impurities in the voids of the slag mound 3. [Figure 2] A diagram illustrating the void in the rubble mound 3. [Figure 3] A diagram illustrating the range from which impurities are removed by suction tube 1. [Figure 4] A diagram showing the design space S formed by combining multiple removal ranges R. [Figure 5] This figure shows an example of a spray pipe 2 installed adjacent to a suction pipe 1. [Figure 6] A diagram showing an example of a spray tube 2a installed inside the suction tube 1. [Figure 7] A diagram showing an example of a nozzle 20a that sprays high-pressure water horizontally. [Figure 8] A diagram showing an example of a waste rock mound suction system 9. [Figure 9] A diagram showing an example of the removal range R in the waste rock mound suction system 9. [Figure 10] This diagram shows an example of a casing 60 for drilling a diagonal hole in the rubble mound 3. [Modes for carrying out the invention]

[0024] <First Embodiment> The following describes a first embodiment of the present invention: a method M for sucking up foreign matter. The foreign matter sucking method M is a method for sucking up and removing foreign matter accumulated in the voids of a rubble mound.

[0025] Figure 1 shows an example of a suction tube 1 used to suck up foreign matter from the voids in the rubble mound 3. In the following description, directions in the rubble mound 3 will be described using the X, Y, and Z axes indicated by the three arrows in the figure. Here, -Z is the direction of gravity, i.e., downward. Also, +X is, for example, the north direction, and +Y is, for example, the west direction.

[0026] The rubble mound 3 is constructed by dumping rubble onto the original ground B, such as the seabed. The rubble mound 3, constructed on the original ground B, will serve as the foundation for the port structure built on top of it. Caisson 4 is an example of a structure built on the top surface 30 of the rubble mound 3.

[0027] The suction tube 1 is inserted downward from the top surface 30 of the rubble mound 3. An opening 10 is provided at the lowest point of the inserted suction tube 1. The suction tube 1 is connected to a suction pump (not shown in Figure 1) at its uppermost end.

[0028] This suction pump is a pump that sucks up water, such as a vacuum pump or a sand pump. If sand, silt, clay, seashells, etc. are dispersed in the water, the suction pump will suck up the sand, silt, clay, seashells, etc. along with the water.

[0029] Suction pumps are installed on the seabed, on scaffolding, on work barges, on quays, etc., depending on the method of disposing of the collected contaminants. Suction pumps may also be installed underwater. For example, a horizontal submersible sand pump may be used.

[0030] By operating this suction pump, the suction tube 1 sucks up water (seawater in this case) along with impurities from the voids in the rubble mound 3 through the opening 10. In this way, the suction tube 1 performs the impurity suction method M.

[0031] Figure 2 is a diagram illustrating the voids in the rubble mound 3. The rubble mound 3 is constructed by piling up rubble stones 31 of various particle sizes that are placed on the original ground B, with each stone supporting the others. There are voids between the rubble stones 31. As shown in Figure 2(a), impurities 32 accumulate in these voids. These impurities 32 include, for example, sand, silt, clay, and seashells. The impurities 32 accumulate in the voids of the rubble stones 31 as described above, for example, by adhering to the rubble stones 31 during the construction of the rubble mound 3, being placed together with the rubble stones, or by being exposed to ocean currents, etc., after the rubble mound 3 has been constructed.

[0032] When the suction pipe 1 shown in Figure 1 sucks up the contaminants 32 shown in Figure 2(a) along with water from the opening 10, the contaminants 32 are removed as shown in Figure 2(b). As a result, the voids in the rubble mound 3 are replaced with water W. Since the contaminants 32 are mainly those that accumulated in the voids after the rubble mound 3 was constructed, the rubble will not sink even if the contaminants 32 are removed.

[0033] Figure 3 is a diagram illustrating the range from which impurities are removed by the suction tube 1. Figure 3(a) shows a top view of the suction tube 1. Figure 3(b) shows a cross-sectional view of the suction tube 1 during suction, viewed from the side along the arrow indicated by line BB in Figure 3(a).

[0034] When the suction tube 1 shown in Figure 3 begins suction, first, any debris near the opening 10 located at the deepest part of the suction tube 1 is removed. As a result, any other debris located around the opening 10 but above it rolls down towards the vicinity of the opening 10 along the arrow shown in Figure 3(b).

[0035] Since the impurities are particles such as sand and seashells, other impurities whose elevation angle as viewed from the opening 10 is smaller than its angle of repose will not roll down into the opening 10 from which the impurities have been removed. Therefore, impurities present around the suction tube 1 are removed in a conical shape with the opening 10 as the apex within a certain radius, and beyond that radius, they are not removed, resulting in a roughly cylindrical shape in the vertical direction of that radius. This conical and cylindrical area from which the impurities have been removed is called the removal range R. The removal range R is the range affected by suction from the suction tube 1. Note that the size of this removal range R varies depending on the performance of the suction pump and the degree of adhesion of the silt, clay, seashells, etc. to be removed, so it is desirable to determine the removal range R each time it is performed.

[0036] Therefore, the impurity suction method M performed by this suction tube 1 is an example of an impurity suction method in which a suction tube is inserted into an existing rubble mound, and impurities in the voids of the rubble mound are sucked out along with water from the opening at the tip of the suction tube.

[0037] Incidentally, the space from which impurities are to be removed (referred to as the design space) is not limited to a conical shape; rather, it is often, for example, a rectangular prism. If the impurities contained in this design space are to be removed using only a suction tube 1 inserted at one point, the suction tube 1 must remove impurities in the removal range R that circumscribing this rectangular design space. This removal range R is larger than the design space mentioned above, and most of it includes an area where impurity removal is not necessary. Therefore, it is desirable that impurity removal be carried out by combining multiple removal ranges R according to the shape of the design space.

[0038] Figure 4 shows a design space S formed by combining multiple removal areas R. Figure 4(a) shows a top view of the design space S. Figure 4(b) shows a cross-sectional view of the design space S, viewed from the side along the line indicated by the arrow BB in Figure 4(a).

[0039] In the rubble mound 3 shown in Figure 4, suction tubes 1a and 1b are inserted at different positions. In the example shown in Figure 4, suction tube 1b is inserted in the -Y direction of suction tube 1a.

[0040] In this rubble mound 3, the design space S, which is the space from which impurities are to be removed, is included in at least one of the removal ranges Ra and Rb (if not distinguished, simply referred to as "removal range R") by the two suction pipes 1a and 1b. Therefore, for example, if the design space S occupies the area from the top surface 30 of the rubble mound 3 to the bottom surface at a depth of h, the openings 10a and 10b of the suction pipes 1a and 1b are inserted so as to be positioned at a predetermined distance Δh deeper than their bottom surface (depth h).

[0041] Furthermore, the horizontal spacing (also called pitch) between suction tubes 1a and 1b is estimated based on the removal range R that can be suctioned by one suction tube 1 in the design space S. Note that suction tubes 1a and 1b may be separate and inserted into the rubble mound 3 at the same time, or a single suction tube 1 may be inserted into the rubble mound 3 at different times to remove impurities.

[0042] In other words, in this case, the method M for removing foreign matter performed by these suction tubes 1a and 1b is an example of a method for removing foreign matter in which a space is set up from which foreign matter is removed by the suction of the inserted suction tube, and the suction tube is inserted so that the opening of the suction tube is positioned at a predetermined distance deeper than the bottom surface of the set space, and the foreign matter is sucked up.

[0043] According to the impurities suction method M of this first embodiment, impurities in the voids of the rubble mound can be removed without using compressed air or the like. Furthermore, according to this impurities suction method M, when a design space is defined in the voids of the rubble mound from which impurities should be removed, the suction pipe can be installed in a position that allows for suction to be performed without excess or deficiency.

[0044] <Second Embodiment> Next, a second embodiment of the present invention, a method M for aspirating foreign matter, will be described. The second embodiment of the method M for aspirating foreign matter is a method for expanding the removal range R of the method M for aspirating foreign matter of the first embodiment.

[0045] Figure 5 shows an example of an injection pipe 2 installed adjacent to a suction pipe 1. Figures 5(a) and 5(b) show a top view of the injection pipe 2. Figure 5(c) shows a cross-sectional view of the injection pipe 2 viewed from the side along the line indicated by the arrow BB in Figure 5(b).

[0046] As shown in Figure 5(a), the injection pipe 2 is positioned so as to contact the outer surface of the suction pipe 1 when viewed from above. The removal range R, from which impurities are removed by the suction of the suction pipe 1, is a circle centered on the suction pipe 1 when viewed from above, as shown in Figure 5(b). The dashed line R1 is the boundary surface of the removal range in the first embodiment. In other words, the area inside the dashed line R1 shown in Figure 5 represents the boundary surface of the range from which impurities are removed by suction of the suction pipe 1 alone, without using the injection pipe 2. Furthermore, when viewed from the side along the line indicated by the BB in Figure 5(b), the removal range R has a shape that combines a triangle with the opening 10 of the suction pipe 1 as its vertex and a roughly rectangular shape in the vertical direction, as shown in Figure 5(c). In other words, the removal range R has a roughly cylindrical shape with its bottom surface on the top surface 30 of the rubble mound 3 and a cone shape at its lower end with its vertex near the opening 10 of the suction pipe 1. However, with the installation of the injection pipe 2, the removal range R is expanded compared to the first embodiment, as shown in Figure 5(b), due to the increased radius of the cylindrical object to be aspirated.

[0047] As shown in Figure 5(c), the injection pipe 2 is equipped with a nozzle 20. This nozzle 20 is positioned adjacent to the opening 10 located at the deepest part of the suction pipe 1. The injection pipe 2 is connected to an injection pump (not shown in Figure 5) at its uppermost end. This injection pump is a pump that injects high-pressure water, such as an intensifier water jet pump or a plunger pump. The injection pump is installed on scaffolding, a work barge, a quay, etc. By driving this injection pump, the injection pipe 2 injects high-pressure water from the nozzle 20 into the gaps in the rubble mound 3.

[0048] The high-pressure water sprayed from the nozzle 20 collides with the debris in the voids of the rubble mound 3. The debris that collides with the high-pressure water is broken down and loosened by the impact pressure of the water. As a result, debris near the nozzle 20 is more easily sucked into the suction pipe 1, and the removal range R deepens, with the debris removal range below the opening 10 becoming deeper, and the conical and cylindrical shaped portions also expanding accordingly.

[0049] In other words, according to the impurity suction method M of this second embodiment, the removal range R can be expanded compared to the case where the spray pipe 2 is not used. Furthermore, the spray pressure of the high-pressure water from the spray pipe 2 is not constant, but may be varied to create a strong or weak spray.

[0050] In the impurity suction method M according to this second embodiment, the timing of injecting high-pressure water into the injection pipe 2 does not need to be synchronized with the timing of suction, as long as high-pressure water can be injected into the rubble mound to assist in the suction of impurities by the suction pipe 1. For example, the following cases A and B can be considered for the timing of injecting high-pressure water into the injection pipe 2. (Case A) The spray pipe 2 completes the injection of high-pressure water before the suction pipe 1 begins suction. (Case B) Suction pipe 1 starts suction and while it is continuing, spray pipe 2 starts spraying high-pressure water.

[0051] <Third Embodiment> Next, a third embodiment of the present invention, a method M for aspirating foreign matter, will be described. The third embodiment of the method M for aspirating foreign matter is a method in which the arrangement of the injection pipe and the direction of injection are changed from the method M for aspirating foreign matter of the second embodiment.

[0052] In the second embodiment, the injection pipe 2 was positioned outside the suction pipe 1 such that the nozzle for injecting high-pressure water was adjacent to the opening 10 of the suction pipe 1. However, the arrangement of the injection pipe 2 is not limited to this.

[0053] Figure 6 shows an example of an injection tube 2a installed inside the suction tube 1. Figure 6(a) shows the injection tube 2a viewed from above. Figure 6(b) shows a cross-sectional view of the injection tube 2a viewed from the side along the line indicated by the arrow BB in Figure 6(a).

[0054] In the third embodiment, the injection pipe 2a is installed inside the suction pipe 1 as shown in Figure 6. The injection pipe 2a is also connected to an injection pump (not shown in Figure 6), similar to the injection pipe 2 shown in the second embodiment. This injection pipe 2a also has a nozzle 20 that sprays high-pressure water downward at its deepest point. The high-pressure water sprayed by the injection pipe 2a makes it easier for impurities present near the nozzle 20 to be drawn into the suction pipe 1, and the removal range R is expanded.

[0055] In other words, the impurity suction method M according to the second and third embodiments is an example of an impurity suction method in which a spray pipe equipped with a nozzle for spraying high-pressure water is installed adjacent to or inside the opening of a suction pipe inserted into a rubble mound, and when impurities are sucked up by the suction pipe, high-pressure water is sprayed into the rubble mound from the nozzle.

[0056] Furthermore, the injection pipes 2 and 2a may be raised and lowered along their longitudinal direction, indicated by arrow D6, as shown in Figure 6(b). In this case, the injection pipes 2 and 2a can be raised and lowered by the drive device 5 shown in Figure 6(b). The drive device 5 is, for example, a lifting device (e.g., a boring machine) attached to the upper end of the injection pipe 2a. In this case, the drive device 5 grips the pipe of the injection pipe 2 or 2a and pulls it upward when raising the injection pipe 2 or 2a, and pulls it down when lowering it. That is, the impurity suction method M in this case is an example of an impurity suction method in which the injection pipe is raised and lowered along the longitudinal direction of the injection pipe by the drive device. Because the injection pipe 2 or 2a is raised and lowered along the longitudinal direction by the drive device 5, the position and distance at which high-pressure water is sprayed are changed, so the range in which impurities are broken down by high-pressure water is easily expanded. In the case of the injection pipe 2a, the range in which the pipe is raised and lowered is such that if it is raised above the opening 10 of the suction pipe 1, the high-pressure water being injected will obstruct the suction itself. For example, the range in which the pipe is raised and lowered is such that it is below the opening 10, as shown in Δd in Figure 6(b).

[0057] Furthermore, although the nozzle 20 was provided to spray high-pressure water downward at the deepest part of the injection pipes 2 and 2a, it may also be provided to spray high-pressure water in a direction other than downward, such as sideways.

[0058] Figure 7 shows an example of a nozzle 20a that sprays high-pressure water horizontally. Figure 7(a) shows a side view of the nozzle 20a installed on the spray pipe 2a. Figure 7(b) shows a top view of the nozzle 20a.

[0059] As shown in Figure 7(a), the nozzle 20a is located at the deepest part of the side surface of the injection pipes 2 and 2a. The opening of the nozzle 20a is oriented, for example, in the +Y direction, so the high-pressure water is ejected from this nozzle 20a in the +Y direction. In this case, since the nozzle 20a ejects the high-pressure water sideways, any contaminants in the direction that the nozzle 20a is facing are more likely to break down and, as a result, are more easily sucked in.

[0060] Furthermore, the injection tubes 2 and 2a may be rotated so that the nozzle 20a rotates circumferentially with respect to their own central axis. In this case, the injection tubes 2 and 2a can be rotated by the drive device 5. For example, the injection tube 2a can be rotated in the direction of arrow D7 shown in Figure 7(b). With this injection tube 2a, the nozzle 20a rotates circumferentially, making it easier to expand the range over which impurities are broken down by high-pressure water. Also, if the opening of the nozzle 20a is not on the central axis of the injection tube 2a, or if the direction of spraying by the nozzle 20a (referred to as the spray direction) is not parallel to this central axis, the spray direction of the nozzle 20a changes as the injection tube 2a rotates. When this spray direction changes, the path through which the high-pressure water sprayed from the opening of the nozzle 20a is drawn into the suction tube 1 also changes over time. Therefore, compared to when the spray direction is not changed, the path of the high-pressure water sprayed from the nozzle 20a is not fixed, and it is easier for it to be sprayed over a wider area.

[0061] In other words, the rotation of the injection tube 2a in this example does not result in a unidirectional injection, nor does it result in a steady injection. Therefore, it does not disturb the area around the suction tube, making it difficult to create a fixed passage through which only high-pressure water passes between rubble, and thus has the effect of increasing the amount of contaminants that can be sucked up. The contaminant suction method M in this case is an example of a contaminant suction method in which the injection tube is rotated by a drive device so that the nozzle rotates circumferentially with respect to the central axis of the injection tube. The injection tube 2a may also be rotated by the reaction force of high-pressure water injected horizontally. The number of nozzles 20a may be one or two or more. Furthermore, the injection pressure of the high-pressure water from the injection tube 2a may not be constant but may be varied to create a strong and weak injection. When using nozzles 20a, it is desirable that the tips of the injection tubes 2 and 2a be located below the opening 10 of the suction tube 1.

[0062] In other words, according to the impurity suction method M of this third embodiment, the removal range R can be expanded compared to the case where the spray pipe 2 is not used.

[0063] <Fourth Embodiment> Next, a method M for sucking up foreign matter according to the fourth embodiment of the present invention will be described. The method M for sucking up foreign matter according to the fourth embodiment is a method for sucking up foreign matter that includes the step of drilling a hole in the rubble mound 3 with a casing prior to inserting the suction pipe 1.

[0064] Figure 8 shows an example of a rubble mound debris suction system 9. This rubble mound debris suction system 9 comprises a suction pipe 1, an injection pipe 2, a suction pump P1, a storage tank T, an injection pump P2, a casing 60, a regulator 7, and a drive unit 5.

[0065] The casing 60 is a tubular component, also known as a casing pipe or casing tube, that is installed on the drilling vessel 6 and drills into the rubble mound 3. The casing 60, lowered by the drilling vessel 6 which is anchored above a predetermined position on the rubble mound 3, is inserted from the top surface 30 of the rubble mound 3 to form the hole A shown in Figure 8. The casing 60 shown in Figure 8 drills into the rubble mound 3 in the -z direction, that is, vertically.

[0066] The suction pipe 1 is inserted into the existing rubble mound 3 and is a pipe that sucks out foreign matter from the voids in the rubble mound 3. The suction pipe 1 shown in Figure 8 is inserted into the hole A drilled by the casing 60 described above.

[0067] The suction pump P1 is connected to the upper end of the suction pipe 1 by piping on its suction side, and is a pump that sucks up seawater along with impurities in the voids of the rubble mound 3 via the suction pipe 1. The suction pump P1 is, for example, a vacuum pump, a sand pump, etc.

[0068] The discharge side of the suction pump P1 is connected to the storage tank T. The storage tank T is a tank that stores the impurities sucked in by the suction pipe 1. The weight of the impurities accumulated in the storage tank T is measured by, for example, a load cell (not shown). Alternatively, the apparent volume of the impurities accumulated in the storage tank T may be measured by a scale marked on the outer wall of the storage tank T. The storage tank T may store the sucked water and impurities separately. If the water and impurities are separated, their weight or volume may be measured separately.

[0069] The injection tube 2 shown in Figure 8 is inserted together with the suction tube 1 into the hole A drilled by the casing 60 described above. Therefore, the debris suction method M performed by the rubble mound debris suction system 9 shown in Figure 8 is an example of a debris suction method in which the suction tube is inserted together with the injection tube into the hole drilled by the casing.

[0070] The injection pipe 2 is installed adjacent to the suction pipe 1 or inside the suction pipe 1. The nozzle 20 provided in the injection pipe 2 is positioned inside the rubble mound 3 near the opening 10 of the suction pipe 1.

[0071] The injection pump P2 has its discharge side connected to the upper end of the injection pipe 2 by piping. The injection pump P2 is a pump that injects high-pressure water downward, sideways, etc., from the nozzle 20 of the injection pipe 2 via the injection pipe 2. The injection pump P2 is, for example, an intensifier water jet pump, a plunger pump, etc.

[0072] Figure 9 shows an example of the removal range R in the rubble mound contaminant suction system 9. The rubble mound contaminant suction system 9 inserts a suction pipe 1 and a spray pipe 2 into a hole A drilled by the casing 60. The spray pipe 2 then sprays high-pressure water laterally from a nozzle 20 to break up contaminants present near the opening 10 of the suction pipe 1. As a result, the suction pipe 1 sucks up the contaminants that have been broken down and made easier to suck up, replacing the voids in the rubble mound 3 with water. Consequently, the suction pipe 1 removes, for example, about 80% of the contaminants in the removal range R shown in Figure 9.

[0073] The drive device 5 shown in Figure 8 is the one described in the third embodiment. This drive device 5 grips the upper end of the injection pipe 2. The drive device 5 is a device that obtains the driving force to move the injection pipe 2 using electricity, an internal combustion engine, etc., and is a motor, engine, etc.

[0074] The drive unit 5 may rotate the injection tube 2 so that the nozzle 20 rotates circumferentially with respect to the central axis of the injection tube 2. Alternatively, the drive unit 5 may raise and lower the injection tube 2 along the longitudinal direction of the suction tube 1.

[0075] The regulator 7 is a device that adjusts the removal range R of impurities in the voids of the rubble mound 3 by changing the conditions of high-pressure water injection from the injection pipe 2. The regulator 7 includes, for example, an interface, a processor, and memory. Manual control is also possible if it can be controlled by the inverter installed in the pump.

[0076] The interface consists of communication circuits and other components that connect to various sensors. The processor is a computing device that acquires information from sensors via the interface and calculates the conditions for the high-pressure water injection described above based on that information. The memory includes RAM (Random Access Memory) which the processor uses as a working area. The memory also includes ROM (Read Only Memory), solid-state drives, hard disk drives, etc., which store computer programs (hereinafter simply referred to as programs) that the processor reads and executes.

[0077] The processor in the adjustment unit 7 is, for example, a general-purpose processor such as a CPU (Central Processing Unit). This processor may also be a programmable logic device such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), or may include these.

[0078] The conditions for high-pressure water injection include, for example, the injection range, injection pressure, and injection volume. It is desirable that the regulator 7 be adjusted using at least one of the conditions for high-pressure water injection, the injection range, injection pressure, and injection volume. In other words, the impurity suction method M performed using this regulator 7 is an example of an impurity suction method that adjusts the range of impurity removal using at least one of the high-pressure water injection range, injection pressure, and injection volume.

[0079] When adjusting the spray range, the regulator 7, for example, opens and closes a solenoid valve provided on the nozzle 20, or changes the direction of movement, movement pattern, etc., of the spray pipe 2 by the drive device 5. When adjusting the spray pressure or spray volume, the regulator 7, for example, changes the rotation speed of the spray pump P2, or changes the opening degree of the discharge valve of the spray pump P2.

[0080] The regulator 7 acquires, for example, data on the weight of water sucked through the suction pipe 1 and data on the weight of impurities sucked along with the water from a load cell installed below the storage tank T. Based on the acquired data, the regulator 7 measures the ratio of the weight of impurities to the weight of water and adjusts the conditions for the injection of high-pressure water by the injection pipe 2 (e.g., injection amount) based on that ratio. In other words, the impurity suction method M performed using this regulator 7 is an example of an impurity suction method that measures the ratio of impurities sucked along with the water to the water sucked through the suction pipe and adjusts the injection amount of high-pressure water by the injection pipe based on the measured ratio.

[0081] The ratio of the weight of impurities to the water, as described above, may be measured by other methods. This ratio may be estimated, for example, by making a portion of the piping connecting the suction pipe 1 and the suction pump P1 transparent or semi-transparent, irradiating the water containing the impurities to be sucked with laser light, and estimating it based on the transmittance. Alternatively, this ratio may be estimated using a densimeter, particle size analyzer, or flow meter. When using this measurement method, a soil transport vessel may be used as the storage tank T. Furthermore, the processor in the regulator 7 is not limited to calculating the conditions for high-pressure water injection based on information obtained from sensors. For example, the processor in the regulator 7 may receive input of information indicating the measurement result from an operator who has visually confirmed the measurement result of the ratio of the weight of impurities to the water sucked through the suction pipe 1. In this case, the processor should calculate the conditions for high-pressure water injection based on the information input from the operator.

[0082] Furthermore, the regulator 7 may control the suction by the suction pump P1 according to the data acquired from various sensors. For example, if the regulator 7 detects that the ratio of impurities to the water sucked through the suction tube 1 has fallen below a threshold for a certain period of time, it may control the suction pump P1 to stop suction by the suction tube 1. In this case, the impurity suction method M performed using this regulator 7 is an example of an impurity suction method in which suction by the suction tube is stopped when the ratio of impurities sucked along with the water sucked through the suction tube falls below a threshold.

[0083] Furthermore, the regulator 7 may acquire data indicating the weight of the impurities accumulated in the storage tank T from the load cell or the like mentioned above, and if this data meets predetermined conditions, it may control the suction pump P1 to stop suction by the suction pipe 1. In this case, the impurities suction method M performed using this regulator 7 is an example of an impurities suction method that includes a storage tank for storing the impurities sucked up by the suction pipe, and stops suction by the suction pipe according to the weight of the impurities accumulated in this storage tank.

[0084] Furthermore, the rubble mound contaminant suction system 9 is an example of a rubble mound contaminant suction system comprising: a suction pipe inserted into an existing rubble mound; an injection pipe installed adjacent to or inside the suction pipe; a suction pump that sucks up contaminants in the gaps of the rubble mound along with water via the suction pipe; an injection pump that sprays high-pressure water from the nozzle of the injection pipe via the injection pipe; a casing that drills a hole in the rubble mound to insert the suction pipe; an adjuster that adjusts the suction force of the suction pump and the spray force of the injection pump; and a drive device that rotates the injection pipe so that the nozzle rotates circumferentially with respect to the central axis of the injection pipe.

[0085] According to the impurity suction method M of this fourth embodiment, the suction pipe 1 can be inserted into the rubble mound 3 more easily than when the rubble mound 3 is not drilled using the casing 60.

[0086] <Variation> The above describes the embodiment, but the contents of this embodiment can be modified as follows. Furthermore, the following modifications may be combined.

[0087] <1> In the fourth embodiment described above, the suction tube 1 was inserted into the hole A drilled by the casing 60, but the casing 60 may also serve as the suction tube 1. In this case, the rubble mound contaminant suction system 9 can use the casing 60, which drilled the rubble mound 3, as the suction tube 1 by leaving it in the hole A. In other words, the contaminant suction method M in this modified example is an example of a contaminant suction method in which the casing is left in the hole drilled by the casing and used as the suction tube 1.

[0088] In this modified example, the injection pipe 2 may already be located outside the casing 60 at the time of drilling. Alternatively, when the upper end of the casing 60, which is placed in the drilled hole A, is connected to the suction pump P1 and used as a new suction pipe 1, the injection pipe 2 may be inserted along the outside or inside of the suction pipe 1. In either case, the injection pipe 2 is inserted into the hole A drilled by the casing 60 and sprays high-pressure water near the tip of the suction pipe 1. In other words, in this modified example as well, the impurity suction method M is an example of an impurity suction method in which a rubble mound is drilled with a casing, an injection pipe is inserted into the hole drilled by the casing, and high-pressure water is sprayed from the injection pipe at the tip of the hole, similar to the fourth embodiment.

[0089] <2> In the fourth embodiment described above, the casing 60 drilled vertically into the rubble mound 3, but the direction of drilling is not limited to vertical. The casing 60 may drill into the rubble mound 3 in a diagonal downward direction, for example. In particular, when a structure such as a caisson 4 is constructed on top of the rubble mound 3, and it is desired to inject a solidifying material such as a plastic grout below the structure, the casing 60 may drill into the rubble mound 3 in a diagonal direction while avoiding the structure.

[0090] Figure 10 shows an example of a casing 60 that drills diagonally into a rubble mound 3. In this case, a caisson 4, which is an example of a structure, is placed on top of the rubble mound 3. The area of ​​the rubble mound 3 directly below the caisson 4 is called the support area U that supports the caisson 4.

[0091] As shown in the fourth embodiment described above, if the only direction in which the casing 60 can drill into the rubble mound 3 is vertical, the casing 60 cannot drill into the support area U, remove impurities, and inject solidifying material because the caisson 4 obstructs it. However, if it is necessary to inject solidifying material into the support area U to construct an improved body in order to strengthen the force supporting the caisson 4, it is necessary to suction and remove the impurities present in this support area U.

[0092] Therefore, in such a case, the casing 60 shown in Figure 10 drills a hole in the rubble mound 3 in a diagonal downward direction. This casing 60 is inserted into the top surface 30 of the rubble mound 3, avoiding the caisson 4, from an area where the caisson 4 is not constructed directly above it. Then, this casing 60 forms a hole A1 inside the rubble mound 3, up to the support area U shown in Figure 10, that is, directly below the caisson 4.

[0093] In other words, the method M for removing foreign matter using this casing 60, which is drilled at an angle, is an example of a method for removing foreign matter in which a riprap mound on which a structure is placed directly above is drilled with the casing while avoiding the structure, so that a hole is formed inside the riprap mound that extends to directly below the structure. According to the method M for removing foreign matter in this modified example, even if a structure such as a caisson 4 is placed on the riprap mound 3, a hole for inserting the suction pipe 1 can be formed directly below the structure. In Figures 8 and 10, a drilling vessel 6 is used to drill the rubble mound 3 with the casing 60. However, to stably drill into the rubble mound using a vessel, it is desirable to use a Self-Elevating Platform (SEP) vessel with its lifting legs fixed to the seabed. Furthermore, the entire support area U described above does not necessarily have to be subject to drilling by the casing 60. For example, when constructing an improved body by injecting a solidifying agent into the drilled area, the casing 60 may be used to drill the support area U1, which is two-thirds from the top and one-third from the left (+y side), as shown in Figure 10.

[0094] <3> In the third and fourth embodiments described above, the injection pipe 2 was raised and lowered by the drive device 5, but the lifting device may also raise and lower the suction pipe 1. In this case, the rubble mound contaminant suction system 9 only needs to be equipped with a drive device that moves the suction pipe 1 up and down. [Explanation of Symbols]

[0095] 1, 1a, 1b... Suction pipe, 10, 10a, 10b... Opening, 2, 2a... Injection pipe, 20, 20a... Nozzle, 3... Rubble mound, 30... Top surface, 31... Rubble, 32... Impurities, 4... Caisson, 5... Drive unit, 6... Drilling vessel, 60... Casing, 7... Regulator, 9... Impurities suction system inside rubble mound, A, A1... Hole, D6, D7... Arrow, P1... Suction pump, P2... Injection pump.

Claims

1. A method for removing foreign matter, comprising drilling a hole in an existing rubble mound with a casing, inserting a suction tube into the hole drilled by the casing, and sucking up foreign matter from the voids of the rubble mound along with water through the opening at the tip of the suction tube.

2. A method for removing foreign matter, comprising drilling a hole in an existing rubble mound with a casing, leaving the casing in the hole drilled by the casing and using it as a suction pipe, and sucking up foreign matter from the voids of the rubble mound along with water from the opening at the tip of the suction pipe.

3. In the rubble mound, an injection pipe equipped with a nozzle for spraying high-pressure water is installed adjacent to the opening of the suction pipe inserted into the suction pipe or inside the suction pipe, and when the suction pipe sucks up the foreign matter, high-pressure water is sprayed into the rubble mound from the nozzle. A method for aspirating foreign matter according to claim 1 or 2.

4. A space is set up in which foreign matter is removed by the suction of the inserted suction tube, the suction tube is inserted so that the opening of the suction tube is positioned at a predetermined distance deeper than the bottom surface of the space, and the foreign matter is suctioned. A method for aspirating foreign matter according to claim 1 or 2.

5. The casing is used to drill a hole in the rubble mound, on which a structure is placed directly above, while avoiding the structure, so that the hole extends to directly below the structure within the rubble mound. A method for aspirating foreign matter according to claim 1 or 2.

6. The nozzle is rotated by the drive device so that it rotates circumferentially with respect to the central axis of the injection tube. The method for aspirating foreign matter according to claim 3.

7. The drive mechanism raises and lowers the injection pipe along its longitudinal direction. The method for aspirating foreign matter according to claim 3.

8. The removal range of the impurities is adjusted using at least one of the spray range, spray pressure, and spray volume of the high-pressure water. The method for aspirating foreign matter according to claim 3.

9. The proportion of impurities drawn in with the water through the suction tube is measured, and the amount of high-pressure water injected by the injection tube is adjusted based on the measured proportion. The method for aspirating foreign matter according to claim 3.

10. When the measured percentage falls below the threshold, suction by the suction tube is stopped. The method for aspirating foreign matter according to claim 9.

11. A storage tank is provided for storing the foreign matter sucked up by the suction pipe. The suction by the suction pipe is stopped according to the weight of the foreign matter accumulated in the storage tank. A method for aspirating foreign matter according to claim 1 or 2.

12. A casing that drills holes into the existing rubble mound to form a hole, A suction tube is inserted into the hole drilled by the casing, A spray pipe installed adjacent to or inside the suction pipe, A suction pump that sucks up water and impurities from the voids in the rubble mound via the suction tube, A spray pump that sprays high-pressure water from the nozzle of the spray pipe via the spray pipe, A regulator for adjusting the suction force of the suction pump and the ejection force of the injection pump, A drive device for rotating the injection tube such that the nozzle rotates circumferentially with respect to the central axis of the injection tube, A system for sucking up foreign matter from within a rubble mound, equipped with the following features.

13. A casing which is placed in a hole formed by drilling a hole in an existing rubble mound and used as a suction pipe, A spray pipe installed adjacent to or inside the suction pipe, A suction pump that sucks up water and impurities from the voids in the rubble mound via the suction tube, A spray pump that sprays high-pressure water from the nozzle of the spray pipe via the spray pipe, A regulator for adjusting the suction force of the suction pump and the ejection force of the injection pump, A drive device for rotating the injection tube such that the nozzle rotates circumferentially with respect to the central axis of the injection tube, A system for sucking up foreign matter from within a rubble mound, equipped with the following features.

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