JP4960402B2 - Dredging method by grab dredger - Google Patents

Description

The present invention relates to the bottom of a grab bucket displaced from the reference position , reference axis and reference direction due to the influence of tidal current etc. in dredging work where the bottom of a predetermined water area is excavated by a grab bucket suspended from a jib of a crane mounted on a grab dredger. It is related with the dredging method by the grab dredger which can implement dredging work correctly and efficiently by grasping | ascertaining the actual state in.

Dredging work to remove routes secure and sediment of ships, harbors, rivers, and smooth the bottom of the canal are those of removing earth, sand, dredging methods widely practiced by grab dredgers As a typical means Has been. In recent dredging work, it is required to dredge only a necessary amount of earth and sand accurately and uniformly so as not to give an excessive load to the environment as well as its efficiency. Therefore, if there is an unfinished part or there is an excess or deficiency in the amount of dredging, it is required to perform repair work again. When the repair work is performed, the work efficiency is remarkably deteriorated, so that the most accurate dredging work is required.

  Therefore, as a construction support system for dredgers that can perform dredging on the seabed accurately even if the water depth changes due to tide level, a system that calculates the water depth value from data such as hull swing and jib tilt angle is provided (Patent Literature) 1). Moreover, in order to make excavation soil thickness uniform, the means to use the grab bucket equipped with the depth meter is also provided (patent document 2). Furthermore, in order to lower the grab bucket efficiently and correctly to a predetermined position on the bottom of the water by grasping the behavior tendency of the grab bucket moving underwater when the grab bucket is lowered into the water, ultrasonic underwater position surveying There is also provided means for attaching a receiver to a main body of a grab dredger using a grab bucket to which a transmitter of the apparatus is attached (Patent Document 3).

Japanese Patent Laid-Open No. 10-60943 JP2004-150015 JP-A-10-227042

  In the dredging work by the conventional grab dredger, the grab bucket suspended from the jib of the crane via the support rope and the opening and closing rope descends directly below the tip of the jib, settles on the bottom of the water as it is, and the jib is located It is assumed that the bottom of the water is excavated by opening and closing the grab along the direction. Based on this premise, the position and depth of the grab bucket that is being worked on are determined based on various information such as the jib turning direction, undulation angle, tide level data, hull position data, and support rope extension length. Calculated and displayed as numerical values and image information in the charter.

  However, there are tidal currents in the inundation area, and depending on the weather, season, and working time, the grab bucket may be washed away in the water, so that it does not fall directly under the tip of the jib and the opening of the grab bucket may rotate. is there. In addition, there is a step caused by terrain or excavation work on the bottom of the water, and the grab bucket that has landed may climb on the step and tilt. In such a case, a deviation occurs between the excavation site recognized by the operator and the actual excavation site.

  For this reason, the operator secures a certain overlapping portion with a portion recognized as having been excavated and excavates a new excavation site to eliminate the above-described deviation. If the deviation is small, there is no problem, but if the deviation is large, the secured overlapping portion cannot be covered and remains as an unfinished portion. In that case, since it is measured as a difference in water depth by the confirmation exploration after the completion of the work, it is necessary to carry out dredging work for repairing the corresponding portion again, which deteriorates work efficiency. On the other hand, when there is no deviation or there is little deviation, it is unnecessary work to secure the large overlapping portion and perform the dredging work, which deteriorates the work efficiency.

  In the examples shown in Patent Document 1 and Patent Document 2, it is not considered at all that the grab bucket is swept away by the tidal current. Further, the ultrasonic underwater position surveying device shown in Patent Document 3 cannot be used when turbidity occurs in the water, and is simply intended to know the behavior tendency of the grab bucket. The position, tilt, or orientation of the opening cannot be known.

  In addition, the depth of the bottom of the dredged area is based on the length of the support rope that is drawn from the actual water surface position of the dredged area to the bottom of the dredged area, and is based on various data such as tide level and dredger heel / trim data. It was calculated after correction. For this reason, no consideration is given to the increase in the amount of the support rope that is fed by the support rope being swept away by the tidal current, resulting in an error in water depth. If this error is large, the depth of the dredging will be excessive and insufficient, and it will be necessary to carry out the dredging work for repair again, thereby deteriorating the work efficiency.

Therefore, the present invention solves the problems of the dredging method using the conventional grab dredger described above, and grasps the actual state of the grab bucket that is displaced from the reference position , reference axis, and reference direction due to the influence of the tidal current and the like. The purpose of the present invention is to provide a dredging method using a grab dredger that can carry out dredging work accurately and efficiently.

For the present invention to achieve its objectives, the grab buckets Tsu支through the supporting rope and closing rope from the jib of the crane that is equipped with grab dredgers, the dredging method for drilling water bottom of a predetermined body of water, Grab buckets Directly equipped with an acceleration sensor and an angular velocity sensor, and the acceleration sensor measures the amount of movement from the reference position of the actual grab bucket at the bottom of the water, and the angular velocity sensor measures the tilt angle and the reference from the reference axis of the actual grab bucket at the bottom of the water. Measure the amount of rotation from the direction, and input the measurement data of the amount of movement, tilt angle, and amount of rotation together with the reference data of the grab bucket reference position, reference axis and reference direction to the data processing arithmetic unit equipped on the grab dredger. The grab bucket at the bottom of the water displaced from the reference data. Obtaining the position and tilt angle and orientation of the operation data, to provide the basic dredging method by grab dredgers for operating the grab bucket on the basis of the calculated data.

In addition, the coordinates of the tip of the jib are used as the reference position of the grab bucket, the vertical axis is used as the reference axis of the grab bucket, and the turning direction of the jib is used as the reference direction of the grab bucket. Trim signal, jib undulation angle signal, jib turning direction signal, grab dredger hull size signal, jib length signal, grab bucket size signal, GPS hull position signal, GPS hull direction signal, support rope extension length signal are added. .

Then, the arithmetic data, with the water bottom depth correction calculation data by the grab bucket is displaced, by correcting the water bottom depth based on the deep level correction calculation data, display the calculation data in grab dredgers, The grab bucket is operated based on the display of the calculation data.

According to the present invention having the above configuration, the amount of movement from the reference position of the bottom grab bucket from the acceleration sensor equipped on the grab bucket, the inclination angle and the reference direction from the reference axis of the bottom grab bucket from the angular velocity sensor The measurement data of the amount of rotation of the grab bucket together with the reference data consisting of the reference position, reference axis and reference direction of the grab bucket is calculated by the data processing arithmetic unit equipped on the grab dredger, so that the actual grab bucket at the bottom of the water displaced from the reference data The position, tilt angle, and direction can be obtained as calculation data. Therefore, the dredging work can be carried out by grasping the actual condition of the bottom of the grab bucket displaced from the reference position , the reference axis and the reference direction due to the influence of the tidal current, etc., and the dredging work can be performed accurately and efficiently. be able to. Moreover, the actual depth of the water bottom can be corrected by obtaining the depth correction calculation data of the bottom of the water due to the displacement of the grab bucket.

The whole side view of the grab dredger used for this invention. The principal part side view of the grab dredger used for this invention. Explanatory drawing which shows roughly the dredging method by the grab dredger concerning this invention. Explanatory drawing which shows roughly the dredging method by the grab dredger concerning this invention. Explanatory drawing which shows roughly the dredging method by the grab dredger concerning this invention. Explanatory drawing of the principal part of this invention. The operation explanatory view of the present invention. The whole side view of the grab bucket used for the present invention. The whole front view of the grab bucket used for the present invention. The operation explanatory view of the present invention. Explanatory drawing which shows the depth display concerning this invention. Explanatory drawing which shows the screen display concerning this invention. Explanatory drawing which shows the state of the conventional dredging work.

Embodiments of a dredging method using a grab dredger according to the present invention will be described below with reference to the drawings. FIG. 1 is an overall side view of a grab dredger used in the present invention, and FIG. 2 is a side view of an essential part thereof. In the figure, reference numeral 1 denotes a grab dredger, which suspends a grab bucket 5 from a jib 4 of a crane 3 mounted on a non-self-propelled work platform ship 2 so as to be movable up and down. 6 is a maneuvering room installed on the work table ship 2, and 7 is a crane operation room.

  As shown in FIG. 8, the grab bucket 5 pivotally supports a pair of left and right shells 8 on a lower frame 9 via a shaft 10 so that the lower end portion of the tie rod 11 is on the shell 8 and the upper end portion is on the upper frame 12. The shell 8 and the upper frame 12 are connected to each other by being pivotally supported. Two support ropes 13 for suspending the entire grab bucket 5 from the crane 3 so as to be movable up and down are connected to the upper surface of the upper frame 12 via a suspension ring 14. A predetermined number of lower sheaves 15 and upper sheaves (not shown) are rotatably supported on the lower frame 9 and the upper frame 12 respectively, and two symmetrically between the lower sheave 15 and the upper sheave. The opening / closing rope 16 is hung and the shell 8 is opened / closed. The open / close rope 16 extends upward through a guide roller disposed on the upper surface of the upper frame 12 and is suspended from the jib 4 of the crane 3. The basic configuration of the grab bucket 5 described above is conventionally known.

  In dredging work, a spud 18 is driven into the bottom 17 of a predetermined dredging area to fix the work table ship 2, and then the support rope 13 and the opening / closing rope 16 fixed to the grab bucket 5 are unwound by the crane 3, In the open state, the grab bucket 5 is lowered to the bottom 17 and then settled, and then the open / close rope 16 is wound up, the shell 8 is closed, the bottom 17 is excavated with a predetermined thickness, and the support rope 13 and the open / close rope 16 are wound up. To raise the grab bucket 5 and lift the excavated earth and sand. Then, this operation is repeated throughout the flooded area.

  In the conventional dredging operation, the grab bucket 5 descends directly below the top sheave 4a located at the tip of the jib 4 as shown by the phantom line in FIG. It is assumed that the bottom 17 is excavated by opening and closing the shell 8 along the azimuth. Based on this premise, the position and depth of the grab bucket 5 that is being worked on, various information such as the turning direction of the jib 4, the undulation angle, tide level data, hull position data, and the length of the support rope extended And is displayed as numerical information or image information in the ship maneuvering room 6 or the crane operation room 7 of the work platform ship 2.

  However, since there is a tidal current in the inundation area, depending on the weather, season, and working time, the grab bucket 5 is swept into the tidal current as shown by the arrow 19 in the water, and the jib 4 as shown by the solid line in FIG. There is a case where it does not descend directly below the top sheave 4a at the tip, and the opening of the shell 8 where the grab bucket 5 is opened may turn. 6, A and B indicate excavation areas per grab bucket 5, 20 indicates the turning center of the crane 3, 21 indicates the direction of the jib 4, and 22 indicates the turning direction of the crane 3. . The digging area A indicated by the phantom line indicates a position and direction area where the grab bucket 5 having the shell 8 opened reaches the water bottom 17 when it is not affected by the tidal current. Dredging work was performed with A as the reference position and reference orientation.

  In reality, however, the grab bucket 5 may be swept away by underwater tides, and does not land on the bottom 17 just below the top sheave 4a at the tip of the jib 4 but along the tidal currents as shown by the arrow 19. The shell 8 is displaced and the opening direction of the shell 8 is also rotated as indicated by the arrow 23, and eventually reaches the bottom of the excavation region B. In such a case, a deviation occurs between the excavation area A recognized by the operator and the actual excavation area B. Reference numeral 24 denotes the center position of the grab bucket 5.

  Further, there may be a step in the bottom 17 due to a step due to topography or excavation work. For this reason, the grab bucket 5 may not only be displaced in a planar position but also climb on the step 25 at the bottom 17 as shown in FIG. Even in such a case, a deviation occurs between the excavation area A recognized by the operator and the actual excavation area B. For example, the drowned water bottom 17a is flattened, but a step 25 is formed on the boundary surface with the undrained water bottom 17b, and the grab bucket 5 rides on the step 25 and tilts. There is. The same applies to the case where the step 25 exists in the undisturbed water bottom 17b itself.

  For this reason, the operator secures a certain overlap with the excavation area recognized as being excavated and excavates a new excavation area, thereby eliminating the above-described deviation. If the deviation is small, there is no problem, but if the deviation is large, it cannot be covered by the secured overlapping portion, and the grab bucket 5 is displaced in the dredging direction indicated by the arrow 26 by the tide in the excavation area as shown in FIG. As a result, the unexcavated region C generated by the above-described operation and the unexcavated region D due to the rotation of the opening of the grab bucket 5 remain as unexposed portions. In that case, since the difference in water depth is measured as the difference in water depth by the confirmation exploration after the completion of the work, it is necessary to carry out dredging work for repairing the unexcavated areas C and D again. The work efficiency will be deteriorated. On the other hand, when there is no deviation or there is little deviation, it is unnecessary work to secure a large overlapping portion and perform the dredging work, which also deteriorates the work efficiency.

  On the other hand, the depth of the water bottom 17 is lowered until the grab bucket 5 is lowered to the position of the actual water surface 27 in the inundation area, the position of the support rope 13 on the water surface 27 is set as a reference point, and the water bottom 17 reaches the water bottom 17. Based on the length L1 of the support rope 13 fed out to the base, the numerical value obtained by adding the height dimension Bh of the grab bucket 5 to the feed length L1 of the support rope 13 is the tide level, heel / trim data of the work platform ship 2, etc. It is obtained by correcting with various data. However, as shown in FIG. 7, even when the grab bucket 5 is swept away by the tidal current and landed at a position shifted by the coordinate BL from the bottom 17c of the jib 4 just below the top sheave 4a, the water depth is just below the top sheave. This is the same as when the water bottom 17c is landed. That is, since the water depth is based on the value obtained by adding the height Bh of the grab bucket 5 to the feed length L1 of the support rope 13 regardless of the bottom position of the grab bucket 5, the actual bottom of the grab bucket 5 An error from the position depth H is generated ("L1 + Bh"> H). As a result, the grab bucket 5 is subjected to excavation work, assuming that the grab bucket 5 has landed at a depth deeper than the actual depth H.

  As shown in FIG. 9, when the grab bucket 5 rides on the step 25 at the bottom 17b and is displaced and tilted in the vertical direction, the central axis 28 of the grab bucket 5 is shifted to the vertical axis 29 as shown in FIG. Therefore, the bottom is inclined by an angle θ. The height dimension Bhα of the grab bucket 5 in this inclined state is lower than the height dimension Bh of the grab bucket 5 that has settled in the vertical state (Bhα <Bh), but in the depth display, it is only in the vertical state. Since this is based on the height dimension of the grab bucket 5 that has settled on the ground, this also causes an error in water depth, and it is assumed that the grab bucket 5 is grounded at a depth deeper than the actual water depth and that excavation work is performed. Become.

The grab bucket 5 is displaced from the reference position due to the influence of the tide or the like, or the adverse effect due to the error in depth is eliminated. In the present invention, the acceleration sensor 30 and the angular velocity sensor 31 are directly mounted on the grab bucket 5. And a dredging method using a grab dredger that grasps the actual state of the bottom of the grab bucket based on the measurement data of the angular velocity sensor 31 and operates the grab bucket 5 during dredging based on the state.

  The acceleration sensor 30 and the angular velocity sensor 31 are housed in a liquid-tight housing box 32 and are directly mounted on the upper frame 12 of the grab bucket 5 as shown in FIGS. The storage box 32 is installed at the center position of the upper frame 12, that is, the center position 24 of the grab bucket 5 shown in FIG. 6 (in the illustrated example, for convenience of explanation, the storage box 32 is shown in a position slightly displaced from the center position. Shown). A transmission cable 33 for transmitting measurement data of the acceleration sensor 30 and the angular velocity sensor 31 is extended from the storage box 32 and linked to the crane 3 via the cable sheave 4b of the jib 4 in conjunction with the lifting and lowering operation of the grab bucket 5. It is wound so that it can be wound and unwound freely. Therefore, the measurement data of the acceleration sensor 30 and the angular velocity sensor 31 can be transmitted to the crane operation room 7 as needed.

  The acceleration sensor 30 can measure the amount of movement from the reference position in the horizontal direction by measuring the acceleration of the object (change in speed per second). As a result, the coordinates of the position at the measured location can be calculated from the reference position. On the other hand, the angular velocity sensor 31 can measure the tilt angle from the reference axis and the rotation amount from the reference azimuth by measuring the angle and angular velocity of the object (the amount of rotation of the object per second). As a result, the tilt angle and orientation at the measured position can be calculated from the reference axis and the reference orientation. In the present embodiment, as the acceleration sensor 30 and the angular velocity sensor 31, commercially available products that are integrated with the acceleration sensor and the angular velocity sensor and that can be stored in the storage box 32 and easily installed at the center position 24 of the grab bucket 5 are used. did.

Next, an outline of a dredging method for obtaining calculation data of the actual position, inclination angle, and direction of the grab bucket 5 at the bottom 17 will be described with reference to FIG. As shown in FIG. 3, the grab bucket position signal 34 (horizontal position coordinates) measured by the acceleration sensor 30 directly mounted on the grab bucket 5 and the angular velocity sensor 31 directly mounted on the grab bucket 5 were measured. The grab bucket inclination signal 35 and the azimuth signal 36 are input to the data processing arithmetic unit 37 installed in the work platform ship 2 via the transmission cable 33, respectively. That is, the acceleration sensor 30 measures the movement amount of the bottom 17 of the grab bucket 5 from the reference position in the horizontal direction, and the angular velocity sensor 31 measures the inclination angle of the bottom 17 of the grab bucket 5 from the reference axis and the reference azimuth. The amount of movement is measured, and these measurement data are input to the data processing arithmetic unit 37.

  Further, the reference position 39, the reference axis 40, and the reference azimuth 41 of the grab bucket 5 are input to the data processing arithmetic unit 37 as the reference data 38. Note that the horizontal position of the top sheave 4a at the tip of the jib 4 is used as the reference position 39 of the grab bucket 5, the vertical axis is used as the reference axis 40 of the grab bucket 5, and the reference orientation 41 of the grab bucket 5 is used. Uses the turning orientation of jib 4.

  Further, as the reference data 38, the tide level signal 42, the heel trim signal 43 of the work table ship 2, the land reference station position signal 44 adjacent to the inundation area, the GPS hull signal 45 of the work table ship 2, the GPS hull of the work table ship 2 Direction signal 46, GPS antenna position 47 of work table ship 2, hull size 48 of work table ship 2, size 49 of grab bucket 5, length 50 of jib 4, undulation angle signal 51 of jib 4, turning direction of jib 4 Data selected from the signal 52, the bottom signal 53 of the grab bucket 5, the corrected depth signal 54 of the grab bucket 5, and other data obtained in other dredging operations are used.

  Then, calculation processing is performed in the data processing calculation device 37 to obtain calculation data 55 of the actual position, inclination angle, and direction of the grab bucket 5 in the bottom 17, and a dredging screen display 56 based on the calculation data 55 is displayed in the cockpit 6. In addition, the operator operates the grab bucket 5 on the basis of the screen display 56.

  FIG. 12 shows an example of the dredging screen display 56, which is displayed in the ship maneuvering room 6, the crane operating room 7, and other necessary places, and can be printed out as necessary. In the left column of the dredge screen display 56, the actual excavation area B of the grab bucket 5 at the bottom 17 is displayed as an image, and the excavated area E so far is displayed as an image. Therefore, the operator can efficiently view the excavated area B and the excavated area E without leaving the unexcavated areas D, that is, without leaving the unexcavated areas C and D as shown in FIG. And dredging work can be carried out without excavating unnecessary overlapping portions. In FIG. 12, an arrow 64 indicates the width region of the dredging area this time, and the water bottom 17 in the range of dredging lines 65 and 66 is excavated according to the design depth. In FIG. 12, the excavated region E excavates the left dredging line beyond 65, which is overexcavated within a certain range.

  Further, in the right column of the screen display 56, the tilt angle with respect to the reference axis 40 consisting of the vertical axis of the grab bucket 5 (left 5.0 ° in the illustrated example) and the rotation direction relative to the reference direction 41 consisting of the turning direction of the jib 4 (Left 5.0 ° in the illustrated example) is displayed as a numerical value and an image. It is possible to perform the dredging operation by accurately recognizing the posture of the grab bucket 5 based on the tilt angle and the rotation direction. In addition, as reference data for grasping the actual state of the bottom of the grab bucket displaced from the reference position due to the influence of the tidal current etc., the undulation angle of the jib 4 (60.0 ° in the example shown), the turning direction of the jib 4 (example shown) Is 2.0 °), the tide level (1.20 m in the illustrated example), and the depth (10.0 m in the illustrated example).

Next, as shown in FIG. 7, the corrected water depth when the grab bucket 5 is displaced by the tidal current and is displaced in the horizontal direction, or climbs on the step 25 at the bottom 17 and is displaced in the vertical direction as shown in FIG. An outline of the wrinkle method for obtaining data will be described with reference to FIG. In addition, about the structure same as the method of obtaining the calculation data 55 of the actual position of the grab bucket 5 shown in FIG. 3, inclination angle, and direction, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 4, the grab bucket position signal 34 (position coordinate in the horizontal direction) measured by the acceleration sensor 30 directly mounted on the grab bucket 5 and the angular velocity sensor 31 mounted directly on the grab bucket 5 were measured. The grab bucket inclination signal 35 and the azimuth signal 36 are input via the transmission cable 33 to the data processing arithmetic unit 60 installed in the work table ship 2. Further, the reference position 39, the reference axis 40, and the reference azimuth 41 of the grab bucket 5 are input to the data processing arithmetic unit 60 as the reference data 38. The data processing arithmetic device 60 may be provided separately from the data processing arithmetic device 37 shown in FIG. 3, or the data processing arithmetic device 37 may be used.

  Further, as the reference data 38, the tide level signal 42, the heel / trim signal 43 of the work table ship 2, the size 49 of the grab bucket 5, the length 50 of the jib 4, the undulation angle signal 51 of the jib 4, and the turning direction signal of the jib 4 52, the data selected from the bottom signal 53 of the grab bucket 5 and other data obtained in the dredging operation is used.

  Then, calculation processing is performed in the data processing calculation device 60 to obtain depth correction calculation data 61 of the bottom 17, obtain a correction depth 62 based on the depth correction calculation data 61, and use the correction depth 62 as a depth display 63. 6 and / or displayed on the crane operation room 7 and also on the screen 56 shown in FIG. 3, the operator recognizes the depth display 63 and operates the grab bucket 5.

  The principle for obtaining the depth correction calculation data 61 will be described with reference to FIGS. As shown in FIG. 7, when the grab bucket 5 has landed at a position shifted by the coordinate BL from the bottom 17c directly below the top sheave 4a, the depth H of the actual bottom position of the grab bucket 5 is from the top sheave 4a. From the height dimension Jh to the water surface 27, the feeding length L1 of the support rope 13, the height dimension Bh of the grab bucket 5 that has settled vertically, and the coordinates BL of the position where the grab bucket 5 actually landed It can obtain | require by the following Numerical formula 1.

Further, as shown in FIG. 10, when the grab bucket 5 is grounded at an angle θ with respect to the vertical axis 29, the height dimension Bhα of the grab bucket 5 in the inclined state and the central axis of the grab bucket 5 The coordinate BLα can be obtained by the following equation from the height dimension Bh of the grab bucket 5 that has settled in the vertical state and the inclination angle θ.
Bhα = sinθ ・ Bh
BLα = cos θ · Bh

  The depth H of the actual bottom position of the grab bucket 5 obtained in this way, the height dimension Bhα of the grab bucket 5 in the inclined state, and the coordinate BLα of the central axis of the grab bucket 5 are input to the data processing arithmetic device 60. By performing arithmetic processing together with the reference data 38, the correction depth 62 that is the actual depth can be obtained.

  FIG. 11 shows an example of the depth display 63, which is displayed at other necessary locations in the boat maneuvering room 6 and the crane operating room 7, and can be printed out as necessary. In the left column of the depth display 63, the opening degree of the grab bucket 5 is displayed with a numerical value (%) and a pointer. Further, the depth correction calculation data 61, the tide level and the extension length of the support rope 13 are displayed as numerical values, and the extension length of the support rope 13, the tide level and the depth corrected by the depth correction calculation data 61 are displayed.

Then the dredging method for obtaining the actual position and tilt angle and azimuth calculation data 55 of the grab buckets 5 shown in FIG. 3, was constructed dredging method for obtaining a depth correction operation data 61 shown in FIG. 4 as an integral An outline of the scissors method will be described with reference to FIG. In addition, about the structure same as the scissors method shown in FIG.3 and FIG.4, the same code | symbol is attached | subjected and the description is abbreviate | omitted. In this method , one data processing arithmetic device 37 is used as the data processing arithmetic device.

  As shown in FIG. 5, the grab bucket position signal 34 (position coordinates in the horizontal direction) measured by the acceleration sensor 30 directly mounted on the grab bucket 5 and the angular velocity sensor 31 mounted directly on the grab bucket 5 were measured. The grab bucket inclination signal 35 and the azimuth signal 36 are input to the data processing arithmetic unit 37 installed in the work platform ship 2 via the transmission cable 33, respectively. Further, the reference position 39, the reference axis 40, and the reference azimuth 41 of the grab bucket 5 are input to the data processing arithmetic unit 37 as the reference data 38. Further, as the reference data 38, the tide level signal 42, the heel trim signal 43 of the work table ship 2, the land reference station position signal 44 adjacent to the inundation area, the GPS hull signal 45 of the work table ship 2, the GPS hull of the work table ship 2 Direction signal 46, GPS antenna position 47 of work table ship 2, hull size 48 of work table ship 2, size 49 of grab bucket 5, length 50 of jib 4, undulation angle signal 51 of jib 4, turning direction of jib 4 Data selected from the signal 52, the bottom signal 53 of the grab bucket 5, the corrected depth signal 54 of the grab bucket 5, and other data obtained in other dredging operations are used.

Then, calculation processing is performed in the data processing calculation device 37 to obtain calculation data 55 of the actual position, inclination angle, and direction of the grab bucket 5 in the bottom 17, and a dredging screen display 56 based on the calculation data 55 is displayed in the cockpit 6. In addition, the operator operates the grab bucket 5 on the basis of the screen display 56. At the same time, the depth correction calculation data 61 of the bottom 17 is obtained by the calculation processing of the data processing calculation device 37, the correction depth 62 is obtained based on the depth correction calculation data 61, and the ship is operated as the depth display 63. In addition to displaying in the room 6 and / or the crane operation room 7, the operator also recognizes the depth display 63 and operates the grab bucket 5 by displaying it on the screen display 56. Furthermore, necessary data can be obtained by inputting various data used in the dredging method as reference data into the data arithmetic processing unit 37 and performing calculations in combination with various data.

According to the dredging method using the grab dredger according to the present invention, the operator can recognize the actual state at the bottom of the grab bucket displaced from the reference position , reference axis and reference direction due to the influence of tidal currents, etc. It is possible to eliminate the gap between the existing excavation site and the actual excavation site. Further, it is not necessary to secure a useless overlapping portion and perform excavation work, and the excavation work for repair can be reduced. Furthermore, it is possible to accurately know the depth of the bottom of the flooded area. Therefore, it is possible to provide a dredging method using a grab dredger that can carry out dredging work accurately and efficiently.

DESCRIPTION OF SYMBOLS 1 ... Grab dredger 2 ... Work table ship 3 ... Crane 4 ... Jib 4a ... Top sheave 4b ... Cable sheave 5 ... Grab bucket 6 ... Ship control room 7 ... Crane operation room 8 ... Shell 9 ... Lower frame 11 ... Tie rod 12 ... Upper frame DESCRIPTION OF SYMBOLS 13 ... Support rope 15 ... Lower sheave 16 ... Opening and closing rope 17, 17a, 17b, 17c ... Water bottom 24 ... Center position (of grab bucket) 25 ... Step 27 ... Water surface 28 ... Center axis of 29 (grab bucket) 29 ... Vertical axis 30 ... Acceleration sensor 31 ... Angular velocity sensor 32 ... Storage box 33 ... Transmission cable 34 ... Position signal 35 ... Tilt signal 36 ... Direction signal 37, 60 ... Data processing arithmetic unit 38 ... Reference data 39 ... Reference position 40 ... Reference axis 41 ... Reference Azimuth 55 ... Calculation data 56 ... 浚 渫 Screen display 61 ... Depth correction calculation data 62 ... Correction depth 63 ... Depth display

Claims (5)

In a dredging method for excavating the bottom of a predetermined water area by a grab bucket suspended from a jib of a crane equipped with a grab dredger via a support rope and an opening / closing rope,
Equipped with an acceleration sensor and angular velocity sensor to grab bucket directly, the inclination angle from the actual measured amount of movement from the reference position of the grab bucket, also the reference axis of the actual grab bucket in the sea bed by the angular velocity sensor in the bottom of the water by the acceleration sensor Measure the amount of rotation from the reference azimuth and measure the amount of movement, tilt angle, and amount of rotation . The data processing arithmetic unit equipped with the grab dredger is the reference data consisting of the reference position, reference axis and reference azimuth of the grab bucket. And calculating the actual position, tilt angle, and direction of the grab bucket at the bottom of the water displaced from the reference data , and operating the grab bucket based on the calculated data Dredging method by dredger. The coordinates of di blanking tip as a reference position of the grab bucket, the vertical axis as a reference axis of the grab bucket, dredging method according to claim 1, wherein the grab dredgers which use pivoting orientation of the jib as a reference orientation of the grab bucket. Reference data includes tide level signal, grab dredger heel trim signal, jib undulation angle signal, jib turning direction signal, grab dredger hull size signal, jib length signal, grab bucket size signal, GPS hull position signal, GPS hull direction The dredging method by a grab dredger according to claim 1 or 2, wherein a signal and a feeding length signal of the support rope are added. 4. A dredging method using a grab dredger according to claim 1, 2 or 3 , wherein as the calculation data, depth correction calculation data of the bottom of the water due to the displacement of the grab bucket is obtained, and the depth of the bottom of the water is corrected based on the depth correction calculation data. By displaying the operation data in grab dredgers, dredging method according to claim 1, 2, 3 or 4, wherein the grab dredgers operating the grab bucket based on the display of the operation data.

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