JP5313733B2 - Pollution prevention device and underwater construction method - Google Patents

Description

  The present invention relates to a pollution prevention device that can be used in underwater construction work such as dredging, and a submerged construction method using the pollution prevention device.

  Conventionally, a pollution prevention frame has been installed in the water to prevent the pollution generated in dredging work, landfill work, pile driving work at the bottom of the water, etc. from spreading into the surrounding water area and causing water pollution. The pollution prevention frame is installed so as to hang a pollution prevention film in a curtain shape on a float that floats on the water surface and surrounds a construction water area (see, for example, Patent Documents 1 and 2).

JP 09-53221 A JP 2005-68930 A

  The grab bucket that is driven by the dredger during dredging work is lowered from the water surface in the pollution control frame into the water and drowned at the bottom of the water, and then lifted, but when the grab bucket rises and goes out of the water into the air, the grab bucket volume The amount of water is reduced in the water area surrounded by the pollution prevention film (in the pollution prevention film). When the water in the pollution control film decreases, the water level in the pollution prevention film decreases, causing a difference in water level between the pollution prevention film and outside the pollution prevention film, and the pollution prevention film is pushed inward and deformed inward. The next time the grab bucket is lowered into water, contact and interference between the grab bucket and the pollution control film will be a problem, which may damage the pollution prevention film, leading to hindrance and delay of dredging work. End up.

  The present invention has been made in view of the above-described problems of the prior art, and a pollution control device capable of preventing the occurrence of deformation of the pollution prevention film accompanying the rise of the grab bucket in a water area surrounded by the pollution prevention film, and underwater construction using the same. The purpose is to provide a construction method.

  In order to achieve the above object, the pollution control device according to the present embodiment can be floated on the surface of the water and can be suspended to the bottom of the water connected to the float to prevent the diffusion of the pollution in water. And a drive means for moving up and down at least the lower end of the pollution prevention film, the drive means for raising a grab bucket for underwater construction in a water area surrounded by the pollution prevention film. In conjunction with this, the lower end of the pollution control film is driven so as to be separated from the water bottom.

  According to this pollution control device, when the grab bucket is raised underwater for underwater construction in the water area surrounded by the pollution prevention film (in the pollution prevention film), the lower end of the pollution prevention film is interlocked with the rise of the grab bucket. Since the grab bucket comes out in the air and the grab bucket volume of water tries to decrease in the pollution prevention film, the water is prevented from flowing between the lower end of the pollution prevention film and the bottom of the water. Flows in. For this reason, since the water level difference does not arise between the inside of the pollution prevention film and the outside of the pollution prevention film due to the rise of the grab bucket, the inside of the pollution prevention film is not deformed. Therefore, the contact and interference between the grab bucket and the pollution prevention film and the occurrence of damage to the pollution prevention film can be prevented. Even if the lower end of the pollution control film is separated from the bottom of the water, water flows into the pollution prevention film from between the lower end and the bottom of the water as described above. It does not spread out.

  In the pollution control device, the driving means drives the bottom end of the pollution control film away from the bottom of the water after the grab bucket starts to rise in the water until it comes into the air, so that the grab bucket is in the air. When it comes out, water can flow into the pollution prevention film from between the lower end of the pollution prevention film and the water bottom.

  Further, the driving means can be driven so that the lower end portion of the antifouling film bottoms in conjunction with the descent of the grab bucket.

  In addition, after the bottom end of the pollution control film is separated from the bottom of the water, the driving means is driven so that the bottom end of the pollution control film comes to the bottom after the grab bucket comes into the air. It is possible to prevent the contamination in the pollution prevention film from spreading out of the pollution prevention film after the inflow into the pollution prevention film is settled.

  Further, the drive means can be wound and rewound by the winch provided in the float part, a motor for rotationally driving the winch, and raising the at least lower end part of the antifouling film. -It is preferable to provide the wire rope connected so that lowering is possible. An air motor or an electric motor can be used as a motor for driving the winch.

  The control unit includes a control unit that controls the driving unit, and a grab bucket detection unit that detects elevation and / or depth of the grab bucket, and the control unit is configured based on a detection result of the grab bucket detection unit. It can be configured to control the drive means. Thereby, the raising / lowering of the lower end part of a pollution prevention film | membrane can be controlled and automatically driven by the raising / lowering state and depth (water depth position) of a grab bucket.

  In addition, as a grab bucket detection means, in order to detect the raising / lowering (winding / lowering) of the grab bucket, for example, each position of raising (winding) / lowering (lowering) of the operation part of the grab bucket is set with a limit switch. There are means for detecting, means for detecting the position of the driving operation unit by the resistance value of a variable resistor attached to the driving operation unit, and the like. Further, in order to detect the depth position of the grab bucket, there are means for detecting the grab bucket depth by the amount of raising and lowering of the grab bucket, means for detecting by the water depth value of a water pressure gauge attached to the grab bucket, and the like.

  The underwater construction method according to the present embodiment is configured such that a pollution prevention film is installed in a predetermined water area using the above-described pollution prevention device, and the graph bucket is surrounded by the pollution prevention film by a work ship equipped with a grab bucket. When underwater construction is performed by moving up and down, the lower end portion of the antifouling film is driven away from the water bottom in conjunction with the ascent of the grab bucket.

  According to this underwater construction method, when raising a grab bucket in the water for underwater construction in a water area (inside the pollution prevention film) surrounded by the pollution prevention film, the pollution prevention film is interlocked with the rise of the grab bucket. Because the grab bucket comes out into the air and the grab bucket volume of water is about to decrease in the pollution prevention film, the water is polluted between the bottom edge of the pollution prevention film and the bottom of the water. It flows into the prevention film. For this reason, since the water level difference does not arise between the inside of the pollution prevention film and the outside of the pollution prevention film due to the rise of the grab bucket, the inside of the pollution prevention film is not deformed. Therefore, contact and interference between the grab bucket and the pollution prevention film and occurrence of damage to the pollution prevention film can be prevented, so that the raising and lowering of the grab bucket for underwater construction can be executed smoothly.

  Even if the lower end of the pollution control film is separated from the bottom of the water, water flows into the pollution prevention film from between the lower end and the bottom of the water as described above. It does not spread out.

  In the underwater construction method, the bottom end of the pollution control film can be driven away from the bottom of the water after the grab bucket starts to rise in the water and then comes out into the air. Further, it can be driven so that the lower end portion of the antifouling film bottoms in conjunction with the descent of the grab bucket.

  In addition, after the bottom end of the pollution control film is separated from the bottom of the water, the bottom of the pollution control film is driven to settle after the grab bucket comes out into the air. It is possible to prevent the contamination in the pollution prevention film from diffusing outside the pollution prevention film after the inflow to the inside is settled.

  ADVANTAGE OF THE INVENTION According to this invention, the pollution prevention apparatus which can prevent the deformation | transformation generation | occurrence | production of a pollution prevention film | membrane accompanying the raise of a grab bucket in the water area surrounded by the pollution prevention film | membrane, and the underwater construction construction method using this can be provided.

It is a perspective view which shows roughly a mode that the pollution control apparatus by this embodiment was installed in water. It is a schematic top view of the pollution control apparatus of FIG. It is a schematic side view of the pollution control apparatus of FIG. It is a side view which shows a mode that a grab bucket descends from a work ship in the pollution prevention film | membrane of the pollution control apparatus 10 of FIGS. It is a side view which shows a mode that a dredging operation | work is performed by the grab bucket within the pollution prevention film | membrane of FIG. It is a side view which shows a mode that the grab bucket of FIG. 5 was closed and the raise started. It is a side view which shows a mode that the grab bucket of FIG. 6 came out in the air from underwater. It is a top view which shows roughly the example of arrangement | positioning of the float part of the pollution prevention apparatus of FIG. It is a side view which shows roughly the operation lever provided in the cab of the work ship of FIGS. It is a block diagram which shows the principal part of the control system of the pollution control apparatus 10 of FIGS. It is a flowchart for demonstrating the process example of the raising / lowering operation | movement of the lower end of a pollution prevention film | membrane in the pollution prevention apparatus interlock | cooperated with raising / lowering of the grab bucket of a work ship, and the dredging by a work ship in this embodiment. It is a flowchart for demonstrating another drive control example which raises / lowers the lower end of the pollution prevention film | membrane of FIG. It is the same side view as FIG. 3 which shows another structure for raising / lowering the lower end of a pollution prevention film | membrane in the pollution control apparatus of FIGS.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a perspective view schematically showing a state in which the pollution control device according to the present embodiment is installed in water. FIG. 2 is a schematic top view of the pollution control device of FIG. FIG. 3 is a schematic side view of the pollution control device of FIG.

  As shown in FIGS. 1 to 3, the pollution prevention device 10 includes a float unit 11 configured by arranging buoyant body pipes 11 a, 11 b, 11 c, and 11 d that can float on the water surface S in a rectangular shape, and a float unit 11. Antifouling film 12 attached to buoyancy body pipes 11a to 11d so as to hang down in the form of a curtain from water to bottom G, and winches 21a, 21b, respectively disposed above buoyancy body pipes 11a, 11b, 11c, and 11d. 21c, 21d.

  The buoyancy body pipes 11a to 11d can be made of steel pipes of a predetermined size. Moreover, the pollution prevention film | membrane 12 can use the sheet | seat and cloth which consist of resin materials, such as polyester.

  A weight 13 made of a chain or the like is attached to the lower end 12z of the pollution prevention film 12, so that the lower end 12z of the pollution prevention film 12 can settle along the water bottom G.

  When the pollution prevention device 10 is installed in water as shown in FIG. 1, the pollution prevention film 12 hanging down from the buoyancy body pipes 11a to 11d is fixed to the bottom G at the lower end 12z and the four walls are formed. An area (construction water area) from the water surface S1 to the water bottom G surrounded by the buoyancy body pipes 11a to 11d can be surrounded.

  As shown in FIGS. 1 to 3, winches 21a, 21b, 21c, and 21d are disposed on the buoyancy body pipes 11a to 11d, respectively. Each winch 21a, 21b, 21c, 21d is rotated by a motor M. The motor M can be constituted by an electric motor or an air motor, and can be operated remotely.

  As shown in FIGS. 1 and 3, the wire ropes WR of the plurality of winches 21 a, 21 a, and 21 a on the buoyancy body pipe 11 a are connected to the weight 13 at the lower end 12 z of the pollution prevention film 12. Each winch 21a is rotated by a motor M to wind up the wire rope WR, so that the lower end 12z of the antifouling film 12 can be lifted away from the bottom G, and each winch 21a is rotated in the reverse direction to rotate the wire rope WR. By lowering, the lower end 12z of the pollution prevention film 12 can be lowered and settled on the bottom G.

  The winches 21b to 21d on the other buoyant body pipes 11b to 11d can also be raised and lowered by lowering the lower end 12z of the pollution prevention film 12 by winding and lowering the wire rope WR by rotating the motor M in the same manner as the winch 21a. It has become.

  In addition, when the motor M is an air motor, the winding and lowering of the wire rope WR due to the rotation / reverse rotation of the motor M can be controlled by switching the air piping line. It can be controlled by switching the direction.

  As shown in FIG. 1, the pollution prevention device 10 is installed such that a rectangular float unit 11 floats on the water surface S in a predetermined water area and surrounds the water surface S1, so that the bottom of the buoyancy body pipes 11a to 11d. By surrounding the construction water area from the water surface S1 to the bottom G with the pollution prevention film 12 hanging down to G, dredging work, landfill work and piles in the construction water area below the water surface S1 (hereinafter also referred to as “inside the pollution prevention film”). Even if pollution occurs due to driving work or the like, it is possible to prevent the pollution from diffusing from the construction water area.

  Next, control for driving the raising / lowering operation of the lower end 12z of the pollution prevention film 12 when dredging work is performed by a work ship in the construction water area will be described with reference to FIGS.

  FIGS. 4 to 7 are side views schematically showing a state in which the pollution control device 10 of FIGS. 1 to 3 is installed in water and the dredging operation is performed by a grab bucket operated by a work ship in the pollution prevention film. 4 is a side view showing a state where the grab bucket descends from the work ship into the pollution prevention film of the pollution prevention apparatus 10 of FIG. 1 to FIG. 3, and FIG. 5 shows the grab bucket in the pollution prevention film of FIG. FIG. 6 is a side view showing a state where the dredging operation is performed, FIG. 6 is a side view showing a state where the grab bucket of FIG. 5 is closed and starts to rise, and FIG. 7 is a state where the grab bucket of FIG. FIG.

  FIG. 8 is a top view schematically showing an arrangement example of the float part, the work ship, and the earth transport ship of the pollution control apparatus of FIGS. 4 to 7 on the water. 4-8, illustration of the winches 21a-21d, the motor M, and the wire rope WR of FIGS. 1-3 is abbreviate | omitted.

  FIG. 9 is a side view schematically showing an operation lever provided in the cab of the work boat shown in FIGS. FIG. 10 is a block diagram showing the main part of the control system of the pollution control apparatus 10 of FIGS.

  As shown in FIGS. 4 to 8, the pollution control device 10 installed in the target water area of the dredging work, the work ship WS in the vicinity of the float 11 of the pollution control device 10, and the dredging work by the work ship WS occurred. A ship carrier DS that transports dredged material such as earth and sand is placed in the target water area for dredging work. The work ship WS is anchored by an anchor or the like as necessary, and performs dredging work while raising and lowering the grab bucket GB suspended by the wire W by the crane CR on the water surface S1 surrounded by the float unit 11.

  Specifically, the work boat WS is provided with a hydraulic power source (not shown), a hydraulic drive winch (not shown) that is driven by the hydraulic source to wind and lower the wire W, and drive control of the hydraulic drive winch. The grab bucket GB can be raised and lowered by winding up and down the wire W supported by the crane CR, and these can be known ones.

  As shown in FIG. 9, when the driver operates the operation lever LB provided in the cab CT of the work boat WS of FIGS. 4 to 7 in the ascending direction U, the hydraulic drive winch is driven to wind up the wire W. When the grab bucket GB is raised and the operation lever LB is operated in the lowering direction D, the hydraulic drive winch lowers the wire W by moving the electromagnetic control valve and lowers the grab bucket GB.

  As shown in FIG. 9, limit switches 26 and 27 are arranged near the lower side of the operation lever LB. When the operation lever LB is in a neutral position as shown by a solid line, the switch is off. Here, when the operating lever LB is operated in the upward direction U as shown by the broken line in the figure, the limit switch 26 is turned on by contacting the limit switch 26, and the on state of the grab bucket GB is determined by this on signal. Can be detected. Further, when the operation lever LB is operated in the descending direction D as indicated by a one-dot chain line in the figure, the limit switch 27 is turned on by contacting the limit switch 27, and the grab bucket GB is lowered by this on signal. Can be detected.

  Further, in the work ship WS, the opening / closing of the grab bucket GB of FIGS. 4 to 7 can be controlled by operating another operation lever. A water depth sensor 25 composed of a water pressure gauge is attached to the grab bucket GB so that the depth (water depth position) of the grab bucket GB can be detected.

  As shown in FIGS. 4 to 8, the work boat WS has a swivel base RT that rotates by turning on a plane on the ship, and the crane CR and the cab CT on the swivel base RT are turned by the turn of the swivel base RT. It is possible to turn in the turning directions r and r ′ of FIG. By turning the crane CR and changing the position of the grab bucket GB, it is possible to move the sediment such as earth and sand held by the grab bucket GB to the earth ship DS close to the work ship WS.

  As shown in FIG. 8, the work ship WS and the float unit 11 of the pollution control device 10 are connected by a connection unit CB. As the dredging operation progresses, the float unit 11 and the underwater pollution control film 12 are connected to each other. By moving together with the work boat WS, it is possible to move to the target water area of the next adjacent dredging work.

  As shown in FIG. 10, the pollution prevention device 10 of FIGS. 1 to 3 has a control unit 24 as a control system, and when the detection signals of the limit switches 26 and 27 and the water depth sensor 25 are input to the control unit 24, 24 controls the motor M which drives each winch 21a-21d of the pollution control apparatus 10 based on these detection signals. The control unit 24 can be configured from, for example, a personal computer (personal computer).

  Next, FIG. 11 is a flowchart (steps) of an example of the raising / lowering operation of the lower end 12z of the pollution prevention film 12 in the pollution prevention apparatus 10 interlocked with the raising / lowering of the grab bucket GB of the work ship WS and the dredging process by the work ship WS (step). A description will be given with reference to S01 to S12).

  As shown in FIG. 4, the crane CR and the wire W of the work boat WS are operated, and the grab bucket GB is positioned in the air above the water surface S1 in the float portion 11 (S01). At this time, the lower end 12z of the pollution prevention film 12 is separated from the water bottom G by the wire rope WR being wound up by the winches 21a to 21d.

  Next, when the operation lever LB in FIG. 9 is operated in the descending direction D, the grab bucket GB suspended by the wire W as shown in FIG. 4 starts to descend in the downward direction a (S02). When an ON signal is generated from the limit switch 27 by the operation of the operation lever LB at this time and is input to the control unit 24 of FIG. 10, the control unit 24 drives the motor M of FIGS. The lower end 12z of the antifouling film 12 is lowered in the downward direction b in FIG. 4 by lowering the wire rope WR wound up by the reverse rotation driving of 21d, and reaches the bottom G together with the weight 13 as shown in FIG. (S03).

  The open grab bucket GB descends underwater from the water surface S1, reaches the bottom G as shown in FIG. 5 (S03), and then is driven and closed in the closing direction c in FIG. 5 (S05). Thereby, the earth and sand etc. of the bottom G are accommodated in the grab bucket GB.

  Next, when the operation lever LB of FIG. 9 is operated in the upward direction U, the closed grab bucket GB starts to upward in the upward direction d as shown in FIG. 6 (S06). When an ON signal is generated from the limit switch 26 by the operation of the operation lever LB at this time and is input to the control unit 24 of FIG. 10, the control unit 24 drives the motor M of FIGS. 21d is driven to rotate and the wire rope WR is wound up, whereby the lower end 12z of the pollution prevention film 12 rises together with the weight 13 in the upward direction e in FIG. 6, and moves away from the water bottom G as shown in FIG. 6 (S07). Accordingly, a gap 30 is formed between the lower end 12z of the pollution prevention film 12 and the water bottom G.

  The grab bucket GB in the closed state rises in the water, rises in the upward direction f as shown in FIG. 7, and comes into the air from the water surface S1 in the float portion 11 (S08). When the grab bucket GB comes into the air from the water, the water for the volume of the grab bucket GB decreases in the pollution prevention film 12 and the water surface S1 in the pollution prevention film 12 tends to decrease. At this time, the pollution prevention film Water flows into the pollution prevention film 12 from the gap 30 formed between the lower end 12z of the twelve and the bottom G in the direction g of FIG. 7 (S09). The inflow of water into the pollution prevention film 12 does not cause a difference in water level between the inside and outside of the pollution prevention film 12 due to the rise of the grab bucket GB into the air, so that the pollution prevention film 12 is deformed inward. In addition, the pollution generated by the dredging operation by the grab bucket GB in the pollution prevention film 12 does not diffuse outside the pollution prevention film 12.

  Next, as shown in FIG. 8, the crane CR is turned in the turning direction r in the drawing by the turntable RT, and then the grab bucket GB is opened, so that sediment such as earth and sand is loaded on the soil carrier DS (S10). .

  Next, the crane CR is turned in the turning direction r 'opposite to the turning direction r in FIG. 8 (S11). When the dredging operation is continued (S12), the process returns to the above step S01. Thereafter, in step S02, the grab bucket GB descends again in the water. At this time, since the pollution prevention film 12 is not deformed inward, the grab bucket GB is in contact with or interferes with the pollution prevention film 12. There is no.

  As described above, according to the pollution control device 10 and the dredging construction method of the present embodiment, when the grab bucket GB is raised in the water for dredging work in the pollution prevention film 12, the grab bucket GB is interlocked with the rise. Then, since the lower end 12z of the pollution prevention film 12 is separated from the bottom G and a gap 30 is formed between the bottom G and the bottom G, the grab bucket GB comes into the air, and the water in the volume of the grab bucket GB is prevented from being polluted. Even if it tries to decrease in the membrane 12, water flows into the pollution prevention membrane 12 from the gap 30 at the lower end 12z of the pollution prevention membrane 12, and therefore, the water level inside and outside the pollution prevention membrane 12 due to the rise of the grab bucket GB. Since there is no difference, deformation to the inside of the pollution prevention film 12 does not occur. Therefore, the contact and interference between the grab bucket GB and the pollution prevention film 12 and the occurrence of damage to the pollution prevention film 12 can be prevented, and the raising and lowering of the grab bucket GB for underwater construction can be executed smoothly.

  If the size of the grab bucket is increased to improve the efficiency of dredging work, the volume of the grab bucket increases and the difference in the water level generated as described above increases. Even if a bucket is used, the problem of contact and interference between the grab bucket and the pollution control film can be effectively prevented, and the efficiency of dredging work can be realized.

  In addition, it is conceivable to suppress the generated water level difference by lengthening the buoyant body pipes 11a to 11d of the float part 11 of the pollution control device 10 and widening the area surrounded by the float part 11. Needs to be moved to the adjacent target water area of dredging work together with the work prevention vessel WS together with the pollution prevention film 12, and since the earth vessel DS is larger than the work vessel WS, it interferes with the widened float part and the work vessel Considering the fact that the float unit 11 cannot be configured widely for reasons such as difficulty in approaching the WS, etc., it is possible to solve the problems of contact and interference between the grab bucket and the pollution prevention film and damage to the pollution prevention film. The pollution control device 10 according to the present embodiment is very useful.

  Next, another drive control example for raising and lowering the lower end 12z of the pollution prevention film 12 will be described with reference to the flowchart (steps S21 to S29) in FIG. In FIG. 11, the raising / lowering of the grab bucket GB is judged based on the position of the operation lever LB in FIG. 9, and the lower end 12 z of the pollution prevention film 12 is moved up and down in conjunction with the raising / lowering of the grab bucket GB. Based on the depth of the grab bucket GB detected by the water depth sensor 25, the control unit 24 controls the raising / lowering of the lower end 12z of the pollution prevention film 12 as shown in FIG.

  That is, from the state where the grab bucket GB is located in the air (S21), the grab bucket GB descends (S22), enters the water, and the depth of the grab bucket GB is relatively shallow near the water surface (zero) by the water depth sensor 25. When the predetermined depth is detected (S23), the lower end 12z of the pollution prevention film 12 is settled (S24).

  Then, after the grab bucket GB is bottomed (S25), the dredging operation is performed and closed (S26), the grab bucket GB rises in water (S27), and the depth of the grab bucket GB is compared with the water depth by the water depth sensor 25. When a deep depth is detected (S28), the lower end 12z of the pollution prevention film 12 is moved away from the water bottom G (S29). Thereafter, the dredging process is performed in the same manner as steps S08 to S12 of FIG.

  As described above, the lower end 12z of the pollution prevention film 12 can be driven and controlled in the same manner as in FIG.

  In FIG. 12, the depth of the grab bucket GB is detected by the water depth sensor 25, but may be detected by other means. For example, the depth of the grab bucket GB may be detected by detecting the amount of winding / lowering of the wire W that raises and lowers the grab bucket GB. In order to detect the amount of winding / lowering of the wire W, for example, there is a means for detecting by the integrated value of the number of rotations of the wire drum of the hydraulic drive winch.

  Moreover, you may control the upper and lower sides of the lower end 12z of the pollution prevention film | membrane 12 based on the depth of the grab bucket GB detected with the water depth sensor 25 as follows. That is, when the depth of the grab bucket GB detected by the water depth sensor 25 in step S02 of FIG. 11 gradually increases (becomes deeper) from the water surface (zero), the lower end 12z of the pollution prevention film 12 is made to bottom in step S03. To. Further, when the depth of the grab bucket GB detected by the water depth sensor 25 in step S06 gradually decreases (becomes shallow) from the deepest position (water depth at the bottom), the lower end 12z of the pollution control film 12 is separated from the bottom G in step S07. Like that.

  Also, from step S07 in FIG. 11 where the lower end 12z of the pollution prevention film 12 is separated from the water bottom G as shown in FIG. 6 to step S03 in which the grab bucket GB is lowered again and the lower end 12z is settled for the next dredging operation. In the meantime, when there is a possibility that the contamination may diffuse out of the pollution prevention film 12 from the gap 30 at the lower end 12z, the inflow of water from the gap 30 into the pollution prevention film 12 is almost completed in step S09 as shown in FIG. Then, it is preferable to control so that the lower end 12z of the pollution prevention film 12 is settled.

  For this reason, for example, as shown by the broken line in FIG. 10, the control system of the pollution prevention apparatus 10 includes the timer 28, and the water depth sensor 25 rises from the grab bucket GB and comes out of the water, and the depth of the grab bucket GB is almost zero. The timer 28 measures the time from the point of time when it is detected, and controls so that the lower end 12z of the pollution prevention film 12 is settled after a predetermined time has elapsed. The predetermined time is preferably shorter than the time during which the inflow of water into the pollution prevention film 12 is almost settled in step S09.

  Next, another configuration for raising and lowering the lower end 12z of the pollution prevention film 12 in the pollution prevention apparatus of FIGS. 1 to 3 will be described with reference to FIG. FIG. 13 is a side view similar to FIG. 3 showing another configuration for raising and lowering the lower end of the pollution prevention film in the pollution prevention apparatus of FIGS.

  In FIG. 3, the lower end 12z of the pollution prevention film 12 is lifted and lowered by the wire rope WR with a plurality of winches 21a to 21d, and the lower end 12z is moved up and down. However, as shown in FIG. The pollution preventing film 12 may be moved up and down by moving the frame-shaped body 31 up and down.

  That is, as shown in FIG. 13, a frame body 31 made of a steel pipe or the like is provided so as to surround the four surfaces of the pollution prevention film 12, and the frame body 31 is connected to the pollution prevention film 12. A wire rope WR is connected. When the winches 21 a to 21 d of FIGS. 1, 2, and 13 are rotated by the motor M to wind up the wire rope WR and lift the frame-shaped body 31, the entire pollution control film 12 below the frame-shaped body 31 is lifted. Are lifted together, the lower end 12z of the pollution prevention film 12 can be raised, and each winch 21a-21d is reversely rotated to wind down the wire rope WR, so that the frame 31 has the pollution prevention film 12 together. By being lowered, the lower end 12z of the pollution prevention film 12 can be lowered and settled on the water bottom G. Note that the vertical position of the frame 31 can be set to an arbitrary position above and below the pollution prevention film 12.

  As described above, the modes for carrying out the present invention have been described. However, the present invention is not limited to these, and various modifications can be made within the scope of the technical idea of the present invention. For example, the means for detecting the raising / lowering state of the grab bucket is not limited to the limit switch as shown in FIG. 9, but may be other means. For example, a rotary potentiometer is attached to the operation lever in FIG. The position (up / down) of the operation lever may be detected by a resistance change between the sliding piece that rotates together with the rotating shaft that rotates by the operation and the resistor that contacts the sliding piece.

  Further, the number of winch motors installed on the float unit 11 in FIGS. 1 to 3 and 13 can be changed as appropriate. Further, as shown by a broken line in FIG. 10, a turning position sensor 29 is arranged on the turntable RT of the work boat WS and the turning position of the crane CR is detected, thereby detecting the turning position of the grab bucket GB. Also good.

  According to the pollution control device and the underwater construction method of the present invention, deformation to the inside of the pollution prevention film accompanying the rise of the grab bucket does not occur in underwater construction such as dredging work in the water area surrounded by the pollution prevention film, Contact and interference between the grab bucket and the pollution control film and occurrence of damage to the pollution prevention film can be prevented, and the grab bucket can be raised and lowered smoothly, so that there is no delay in underwater construction.

DESCRIPTION OF SYMBOLS 10 Pollution prevention apparatus 11 Float part 12 Pollution prevention film 12z Lower end and lower end part of pollution prevention film 21a-21d Winch 24 Control part 25 Depth sensor 26, 27 Limit switch 30 Clearance WS Work ship CR Crane W Wire GB Grab bucket LB Operation lever (Operation control section)
M Motor WR Wire rope G Water bottom S Water surface S1 Water surface in float 11

Claims (8)

A float that can float on the water surface;
In order to prevent diffusion of pollution in water, a pollution prevention film that is connected to the float part and can hang down to the bottom of the water,
Driving means for moving up and down at least the lower end of the pollution control film,
The drive means drives the bottom end of the pollution control film to move away from the water bottom in conjunction with the rise of the grab bucket for underwater construction in the water area surrounded by the pollution prevention film. apparatus.   2. The pollution control device according to claim 1, wherein the driving means drives the bottom end of the pollution control film so as to separate from the bottom of the water after the grab bucket starts to rise in the water until it comes into the air.   The pollution control device according to claim 1 or 2, wherein the driving means is driven so that a lower end portion of the pollution prevention film is bottomed in conjunction with a descent of the grab bucket.   The drive means includes a winch provided in the float part, a motor for rotationally driving the winch, and winding and rewinding by the winch, and raising and lowering at least the lower end part of the antifouling film The pollution prevention apparatus of any one of Claim 1 thru | or 3 provided with the wire rope connected so that can be performed. A control unit for controlling the driving means;
Grab bucket detecting means for detecting the raising and lowering and / or depth of the grab bucket,
The pollution control device according to any one of claims 1 to 4, wherein the control unit controls the driving unit based on a detection result of the grab bucket detection unit. A pollution control film is installed in a predetermined water area using the pollution control device according to claim 1,
When the underwater construction is performed by raising and lowering the graph bucket with respect to the water area surrounded by the anti-contamination membrane by a work ship equipped with a grab bucket, the lower end portion of the anti-contamination membrane is interlocked with the rise of the grab bucket. An underwater construction method characterized by driving away from the bottom of the water.   The underwater construction method according to claim 6, wherein the grab bucket is driven so that a lower end portion of the antifouling film is separated from a water bottom after the grab bucket starts to rise in the water and comes out into the air.   The underwater construction method according to claim 6 or 7, wherein the underwater construction method is driven so that a lower end portion of the antifouling film is settled in conjunction with the descent of the grab bucket.

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