JP5874998B2 - Dredging method using grab dredger - Google Patents

Description

  The present invention relates to a dredging method using a grab dredger that dreds a bottom of a port or the like using a grab dredger having a grab bucket in which a pair of shells are opened and closed.

  In this type of dredging method, a grab dredger is used in which the grab bucket is lifted and supported by lifting means such as a crane, and the grab bucket is lowered while both shells constituting the grab bucket are open. The water bottom portions are excavated by penetrating the blade tips of both shells into the water bottom portions and lifting the grab bucket while closing both shells from that state.

  In the dredging method using such a grab dredger, there has been a problem that when the grab bucket is grounded to the bottom of the water and the blade edge of the shell is penetrated into the bottom of the water, the pollution is diffused.

  Conventionally, as a method for solving such a problem, a pollution diffusion prevention frame is floated on the surface of the dredging area, and a pollution diffusion prevention curtain is installed under the pollution diffusion prevention frame. A method of preventing diffusion of pollution by lowering a grab bucket in a region surrounded by a diffusion prevention frame and a pollution diffusion prevention curtain is used as a standard (for example, Patent Document 1). reference).

  However, in the method using the pollution diffusion preventing frame and the curtain as described above, there is a possibility that the pollution diffuses from the gap between the curtain lower edge and the water bottom when the grab bucket is settled. .

  On the other hand, in recent years, it is known that the diffusion of pollution can be suppressed by bottoming the grab bucket at a low speed, and considering the work efficiency, the grab bucket is lowered at a predetermined distance from the water bottom. It is known that the grab bucket is lowered to the speed switching position at the descending standard speed, and then the grab bucket is lowered at the descending speed that is lower than the descending standard speed in the region below the descending speed switching position. (For example, refer to Patent Document 2).

  The standard descent speed here is the speed at which the grab bucket can be lowered most safely and efficiently based on various conditions that determine the performance of the lifting means such as grab bucket weight, crane performance, and suspension wire strength. It shall be said.

JP 2004-68268 A JP 2006-27830 A

  However, the conventional techniques as described above do not consider the geology of the target area when setting the descent speed switching position and the descent speed, and further determine the descent speed switching position and the descent speed. There is a lack of clear grounds, and depending on the combination of the geological state, the descent speed switching position, and the descent speed, there is a possibility that the pollution diffusion suppressing effect is excessive or insufficient.

  Moreover, in this kind of prior art, there existed a problem that the spreading | diffusion of the pollution produced when raising a grab bucket from a water bottom was not fully considered.

  Therefore, in view of such a conventional problem, the present invention has an object to provide a dredging method using an efficient grab dredger that can suitably suppress diffusion of pollution when the grab bucket is moved up and down. It was made as.

In order to solve the above-described conventional problems and achieve the intended object, the feature of the invention described in claim 1 is that a grab bucket configured to open and close a pair of shells facing each other, and Using a grab dredger equipped with lifting and lowering means for suspending and supporting the grab bucket and measuring means for measuring the bottom position of the grab bucket, the grab bucket is lowered with both the shells open, and the both shells In the dredging method in which both the shells are closed at the bottom of the water and the grab bucket is lifted in that state to excavate the bottom of the water, the grab dredger includes the lifting means and the measuring device. Control means for controlling the operation of the means, the measuring means is operated by the control means to measure the bottom surface position, and the bottom surface is measured based on the measured bottom surface position. When the grab bucket is lowered , the descending speed switching position is automatically set at a position separated by a predetermined distance, and the descending slowing speed lower than the descending standard speed is automatically set accordingly. When the bucket Ru is lowered by the lowering standard speed until the lowering speed switching position, wherein the control means in the lowering speed switching position switches the lowering speed of the grab bucket, said to said sea bed than the lowering speed switching position lowered After lowering at a slow speed, closing both shells and excavating the bottom of the water , the measuring means is operated by the control means to measure the bottom surface after excavation, and the measured post-excavation water automatically set the slow increase creep speed than increase normal speed based on the bottom position, the rising speed switched to a position at a predetermined distance from the excavation after the water bottom accordingly Position automatically sets the, when increasing the grab bucket, the grab bucket by the control means is raised to the raised speed switching position than the bottom of the water at the elevated creep speed, the glove in the increase rate switching position The raising speed of the bucket is switched, and the grab bucket is raised at the rising standard speed from the rising speed switching position.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the control means controls the lowering speed switching position, the lowering slowing speed, the rising speed switching position, and the ascending slowing speed based on geological data. The speed is set automatically .

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect , the grab bucket is temporarily stopped at the descending speed switching position and the ascending speed switching position.

The feature of the invention described in claim 4 is that, in addition to the configuration of any one of claims 1 to 3 , the descending slowing speed is set to 1/4 to 1/2 of the descending standard speed.

According to a fifth aspect of the present invention, in addition to any one of the first to third aspects, the lowering speed switching position is 3 to 5 m from the water bottom.

A feature of the invention described in claim 6 is that, in addition to the structure of any one of claims 1 to 4 , the ascending speed is set to 1/4 to 1/2 of the ascending standard speed.

The feature of the invention described in claim 7 is that, in addition to the structure of any one of claims 1 to 5, the ascending speed switching position is set to 1 to 3 m from the bottom surface after excavation.

  As described above, the dredging method using the grab dredger according to the present invention includes a grab bucket in which a pair of shells facing each other are opened and closed, and an elevating means for suspending and supporting the grab bucket so as to be movable up and down. And a grab dredger equipped with a measuring means for measuring the bottom position of the water, the grab bucket is lowered with both the shells open, and both the shells are inserted into the bottom of the water. In the dredging method in which both the shells are closed and the grab bucket is raised in that state to excavate the bottom of the water, the bottom surface position is measured by the measuring means, and the predetermined bottom surface is determined based on the bottom surface position. The lowering speed switching position is set at a position separated by a distance, and the lowering and slowing speed lower than the lowering standard speed is set, and the grab bucket is lowered. The measuring means is lowered to the degree switching position at the descending standard speed, lowered from the descending speed switching position to the water bottom at the descending speed, and then closed both shells to excavate the water bottom. And measuring the bottom surface position after excavation, and setting the ascending speed switching position at a position separated from the bottom surface after excavation by a predetermined distance based on the measured bottom surface position after excavation, and from the ascending standard speed Is set at a low ascending speed, and the grab bucket is raised from the bottom to the ascent speed switching position at the ascending speed, and then the grab bucket is moved at the ascending standard speed from the ascent speed switching position. By raising, it is possible to suitably suppress the diffusion of pollution during dredging work by the grab bucket, and to lower and raise the grab bucket. It can be efficiently performed dredging while ensuring adequate pollution spreading suppression effect by setting the speed switching position and creep speed, respectively.

  In the present invention, the grab bucket is temporarily stopped at the descending speed switching position and the ascending speed switching position, so that it is possible to surely switch from the standard speed to the slow speed, and the water flow accompanying the lifting operation affects the bottom of the water. The influence can be suppressed, and a high pollution diffusion suppressing effect can be obtained.

Further, in the present invention, sufficient pollution can be achieved by automatically setting the descending speed switching position, the descending slowing speed, the ascending speed switching position, and the ascending slowing speed by the control means based on data relating to geology. It is possible to efficiently perform the dredging work while ensuring the diffusion suppressing effect.

  Furthermore, in the present invention, the descending slowing speed is set to 1/4 to 1/2 of the descending standard speed, so that the dredging work can be efficiently performed while ensuring a sufficient pollution diffusion suppressing effect.

  Moreover, in this invention, the said descent speed switching position can suppress suitably the influence which the water flow accompanying the descent | fall operation | movement of a grab bucket exerts on a water bottom part by setting it as 3-5 m from the said water bottom face.

  Furthermore, in the present invention, the ascending speed is set to ¼ to ½ of the ascending standard speed, so that the dredging work can be efficiently performed while ensuring a sufficient pollution diffusion suppressing effect.

  Furthermore, in the present invention, the ascending speed switching position is set to 1 to 3 m from the bottom surface after excavation, so that dredging work can be performed efficiently while ensuring a sufficient pollution diffusion suppressing effect.

  In the present invention, the grab dredger includes control means for controlling operations of the grab bucket, the elevating means, and the measuring means, and the control means sets the water bottom position and the post-digging water bottom position to the measuring means. By automatically setting the descending speed switching position, the descending slowing speed, the ascending speed switching position, and the ascending slowing speed based on the measured bottom position or the bottom position after excavation Mistakes can be prevented.

It is a side view which shows an example of the grab dredger used for the dredging method using the grab dredger which concerns on this invention. It is a front view for demonstrating the descending operation | movement of the grab bucket in the dredging method using the grab dredger which concerns on this invention. It is a front view for demonstrating the raising operation | movement of a grab bucket same as the above. It is a graph which shows the result of the experiment conducted about the relationship between the combination of a descent speed switching position and descent slow speed, and the pollution diffusion suppression effect, (a) is a graph which shows a result when N value = 0, (b) is It is a graph which shows a result when N value = 5. It is a graph which shows the result of the experiment conducted about the relationship between the combination of an ascending speed switching position and an ascending speed, and a pollution diffusion suppression effect, (a) is a graph which shows a result when N value = 0, (b) is It is a graph which shows a result when N value = 5.

  Next, an embodiment of the dredging method using the grab dredger according to the present invention will be described based on the embodiments shown in the drawings.

  First, a grab dredger used in the method of the present invention will be described.

  As shown in FIG. 1, the grab dredger 1 includes a grab bucket 3 in which a pair of shells 2 and 2 facing each other are opened and closed, and an elevating means 4 that suspends and supports the grab bucket 3 so as to be movable up and down. A measuring means 5 for measuring the position of the bottom of the water, and a control means for controlling the operation of the grab bucket 3, the lifting means 4 and the measuring means 5, and the grab bucket 3 is surrounded by a frame 6 for preventing pollution diffusion and a curtain 7. The water bottom B in the area is dredged.

  This grab dredger 1 is a push-boat type, and can move on the water according to the work process. In addition, the code | symbol 8 is a spat (fixing pile) in the figure, and it is driven toward the bottom of the water so that the grab dredger 1 can be fixed at a predetermined position.

  The lifting / lowering means 4 is composed of a crane mounted on the grab dredger 1, and the grab bucket 3 is suspended from the tip of the suspension wire 9 fed out from the jib 4 a, and the suspension wire 9 is fed out and wound. The grab bucket 3 can be moved up and down by the taking operation.

  The elevating means 4 is provided with position management means such as a GPS transmitter, and the position management means outputs position information such as a jib inclination angle and a crane turning angle to the control means.

  The lifting / lowering means 4 includes a length measuring means for measuring the feeding length of the hanging wire 9 and a speed measuring means for measuring the feeding or winding speed of the hanging wire 9. The torque converter is controlled based on the operation information output from the length measuring means and the speed measuring means, and the extending and winding operation of the hanging wire 9, that is, the extending length, the feeding speed and the winding of the hanging wire 9 are performed. The speed can be controlled, whereby the position of the grab bucket 3, the lowering speed, and the rising speed can be controlled.

  Further, a series of operations of lowering, excavating and ascending the grab bucket 3 are sequence-controlled by the control means.

Here, the lifting speed of the grab bucket 3 is determined based on various conditions that determine the performance of the lifting / lowering means 4 such as crane performance, grab bucket weight, suspension wire strength, etc. The speeds at which the lifting / lowering operation can be performed are referred to as a descending standard speed DV0 and a rising standard speed UV0, respectively. For example, lowering the standard speed DV0 and elevated standard speed UV0 when using 20 m ³ grade grab bucket 3 is 1 to 2 m / s.

  On the other hand, for the grab bucket 3, for example, a double cord type is used, and by operating a wire 10 for opening / closing operation different from the hanging wire 9 fed out from the jib 4a, both shells 2, 2 opening and closing operations are performed.

  Further, the grab dredger 1 is provided with a measuring means 5 at the bow portion so that the position of the bottom surface of the water under the grab bucket 3 can be measured.

  For example, a narrow multi-beam detector or a 3D sonar is used as the measuring means 5 so that the position of the bottom of the water (depth) can be measured and the shape of the bottom of the bottom of the water can be measured three-dimensionally and over a wide range. It has become.

  Next, the embodiment shown in FIGS. 2 and 3 will be described with respect to the dredging method using the grab dredger 1 as described above.

  First, before starting dredging work, data (N value etc.) relating to the geology of the dredging target area is measured, and the measured geological data is input to the control means.

  Next, while moving the grab dredger 1 to the dredging target position, the pollution diffusion preventing frame 6 and the curtain 7 are installed to surround the dredging target area.

  Then, based on the position information such as the jib inclination angle and crane turning angle by the position management means, the crane 4 is operated to move the grab bucket 3 to the saddle position, and the dredging work is performed at that position by the sequence control by the control means.

In this dredging operation, first, the control means operates the measuring means 5 to measure the bottom surface B position in the dredging area, and based on the above-mentioned geological data and bottom surface position data, the descent speed switching position DCP and the descent slow speed DV1. Is set automatically .

  The descending speed switching position DCP is set to 3 to 5 m from the bottom of the water, and the descending slow speed DV1 is set to be lower than the descending standard speed DV0, specifically, the speed is 1/4 to 1/2 of the descending standard speed DV0.

  Further, the combination of the descending speed switching position DCP and the descending slow speed DV1 is selected by the control means based on the calculation from the viewpoint of the pollution diffusion suppression effect, economy, and the like.

  That is, in the descending operation of the grab bucket 3, the influence of the descending speed switching position DCP is large, and as the descending speed switching position DCP is farther from the bottom of the water, the pollution diffusion suppressing effect is high. Therefore, the control means selects the fastest descending slow speed DV1 that satisfies the pollution diffusion suppressing effect according to the selected descending speed switching position DCP.

  After the setting of the descent speed switching position DCP and the descent slowing speed DV1 is completed, the control means operates the elevating means 4 based on the set descent speed switching position DCP to feed out the hanging wire 9 to change the descent speed. The grab bucket 3 is lowered with both shells 2 and 2 opened at the descending standard speed DV0 to the position DCP, and the grab bucket 3 is temporarily stopped at the descending speed switching position DCP.

  Thus, by temporarily stopping the grab bucket 3 at the descending speed switching position DCP, the switching from the descending standard speed DV0 to the descending slow speed DV1 can be performed reliably, and the water flow accompanying the descending operation of the grab bucket 3 is water. The influence on the bottom can be suppressed.

  Then, once stopped, the control means operates the elevating means 4 while controlling the torque converter, and lowers the grab bucket 3 to the bottom of the water at the descending slow speed DV1 set from the descending speed switching position DCP. The blade edge portion of 2 is penetrated into the bottom B.

  Next, the control means operates the operating wire 10 in the direction in which both the shells 2 and 2 are closed, winds up the hanging wire 9 and moves the cutting edge portions of the shells 2 and 2 in the horizontal direction. The bottom B is excavated by closing both shells 2 and 2.

  Further, the control means causes the measuring means 5 to measure the bottom position B1 after excavation along with the excavation operation, and based on the measurement data of the bottom position B1 after excavation and the above-described geological data, the ascent speed switching position UCP and the ascending slow speed. Set UV1.

  The ascending speed switching position UCP is 1 to 3 m from the bottom water surface B1 after excavation, and the ascending slowing speed UV1 is lower than the ascending standard speed UV0, specifically, the speed is 1/4 to 1/2 of the ascending standard speed UV0. Is set.

  Further, the combination of the ascending speed switching position UCP and the ascending slow speed UV1 is selected by the control means based on the calculation by the control means from the viewpoint of the pollution diffusion suppression effect, economy, and the like.

  That is, in the ascending operation of the grab bucket 3, the influence of the ascending speed UV1 is large, and the slower the ascending speed UV1 is, the higher the pollution diffusion suppressing effect is. The shortest rising speed switching position UCP that satisfies the pollution diffusion suppressing effect is selected.

  As described above, in the descending operation and the ascending operation of the grab bucket 3, by selecting different speed switching positions and slowing speeds, the optimum combination of the speed switching position and the slowing speed is selected in each of the descending and lifting operations. Thus, the dredging operation can be performed more efficiently than in the case where the speed switching position and the slowing speed in the descending operation and the ascending operation are uniformly set.

  Then, after the setting of the ascending speed switching position UCP and the ascending slowing speed UV1 is completed, the control means winds the suspension wire 9 while controlling the winding speed, and the ascending speed switching position from the bottom surface B1 after excavation. The grab bucket 3 is raised to the UCP at the rising slow speed UV1, and the grab bucket 3 is temporarily stopped at the rising speed switching position UCP.

  Thereafter, the suspension wire 9 is wound up while controlling the wire feeding length and the winding speed, the grab bucket 3 is raised to the surface at the rising standard speed UV0, the crane 4 is operated, and the grab bucket 3 is moved. The shell 10 is moved on the soil carrier and the open / close operation wire 10 is operated to open both shells 2 and 2, and the excavated clay is put into the soil carrier.

  Then, after repeating the above dredging operation while moving the place in the dredging area surrounded by the pollution diffusion preventing frame 6 and the curtain 7, the above series of operations is repeated while moving the grab dredger 1.

In the embodiment described above, comprising a grab dredger control means, grab bucket by the control unit, an example has been described which is adapted to automatically control the lifting means and the measuring means, grab bucket, a lifting hand stage Each operator may be operated manually.

  Next, an experiment conducted on the relationship between the combination of geology, speed switching position and slow speed and the effect of suppressing pollution diffusion will be described.

  In this experiment, in the silt ground at two points (N value = 0, N value = 5) having different soil properties (N value), the combination of the descending speed switching position DCP and the descending slow speed DV1 and the ascending speed switching position UCP The grab bucket 3 is lowered and raised for a plurality of cases having different combinations with the rising and slowing speed UV1, and the turbidity value in the area surrounded by the pollution diffusion preventing frame 6 and the curtain 7 is turbid. It was measured with a dynamometer, converted into an SS value (mg / L), and compared with the SS value when the grab bucket 3 was lowered or raised at a standard speed. The results are shown in Tables 1 to 4 and FIGS.

  The SS values shown in Tables 1 to 4 are measured at a plurality of water depths of 8 m to 13 m and the average values thereof are shown, and the reduction rates shown in Tables 1 to 4 are respectively The reduction rate of each CASE on the basis of CASE 1-0, 2-0, 3-0, 4-0 is shown.

  As can be seen from the above results, in the descending operation of the grab bucket 3, as shown in Tables 1, 2 and 4, when the descending slow speed DV1 is set to 1/4 and 1/2 of the descending standard speed DV0. It can be seen that there is no significant difference between the two, and on the other hand, a higher pollution diffusion suppression effect can be obtained when the descending speed switching position DCP is installed at 5 m from the bottom than when it is installed at 3 m from the bottom. That is, it can be seen that the pollution diffusion suppression effect in the descending operation of the grab bucket 3 is greatly influenced by the descending speed switching position DCP.

  On the other hand, in the ascending operation of the grab bucket 3, as shown in Table 3, Table 4 and FIG. 5, there is a large difference between the case where the ascending speed switching position is set to 1 m from the bottom and the case where it is set to 3 m from the bottom. On the other hand, when the rising slow speed UV1 is set to ¼ of the rising standard speed UV0, the pollution diffusion is higher when the rising slow speed UV1 is set to ¼ of the rising standard speed UV0. It turns out that the suppression effect is acquired. That is, it can be seen that the effect of suppressing the pollution diffusion in the ascending operation of the grab bucket 3 is greatly influenced by the ascending speed UV1.

  Furthermore, when comparing geology (N value), the diffusion of pollution is less when the N value is higher (N value = 5), that is, when the soil is harder than when the N value is low (N value = 0).

  Therefore, considering the geology, by selecting the optimal speed switching position and slowing speed combination for each of the descending operation and the ascending operation, it is efficient while ensuring a sufficient pollution diffusion suppression effect through a series of dredging operations. It can be confirmed that it can be performed well.

B Bottom DCP Lowering speed switching position UCP Ascent speed switching position DV0 Lowering standard speed DV1 Lowering speed UV0 Ascending standard speed UV1 Ascending speed 1 Grab dredger 2 Shell 3 Grab bucket 4 Lifting means (crane)
5 Measuring Means 6 Pollution Diffusion Prevention Frame 7 Pollution Diffusion Prevention Curtain 8 Spat 9 Hanging Wire 10 Opening / Closing Operation Wire

Claims (7)

A grab dredger equipped with a grab bucket in which a pair of shells facing each other is opened and closed, lifting means for suspending and supporting the grab bucket so as to be movable up and down, and measuring means for measuring the bottom position of the water is used. The grab bucket is lowered in a state where both the shells are opened, and both the shells are penetrated into the bottom of the water, and then the shells are closed at the bottom of the water, and the grab bucket is lifted in the state. In the dredging method of excavating the bottom of the water,
The grab dredger comprises control means for controlling the operation of the lifting means and the measuring means,
The measuring means is operated by the control means to measure the water bottom position, and a descent speed switching position is automatically set at a position separated from the water bottom by a predetermined distance based on the measured water bottom position. In response to this, the descent speed that is slower than the descent standard speed is automatically set,
When lowering the grab bucket, the when the grab bucket Ru is lowered by the lowering standard speed until the lowering speed switching position, wherein the control means in the lowering speed switching position automatically switch the lowering speed of the grab bucket , Descending from the descending speed switching position to the water bottom at the descending slow speed,
After excavating the bottom of the water by closing both shells, the control means operates the measuring means to measure the bottom surface after excavation, and the rising standard is based on the measured post-excavation bottom surface position. to automatically set the slow increase creep speed than the speed, automatically set the rising speed switching position to a position spaced a predetermined distance from the excavation after the water bottom accordingly,
When raising the grab bucket, the control means raises the grab bucket from the water bottom to the ascent speed switching position at the ascending speed, and automatically raises the grab bucket at the ascent speed switching position. A dredging method using a grab dredger characterized in that the grab bucket is lifted at the rising standard speed from the switching and rising speed switching position. The dredging using the grab dredger according to claim 1 , wherein the descending speed switching position, the descending slowing speed, the ascending speed switching position, and the ascending slowing speed are automatically set by the control means based on geological data. Method. The dredging method using the grab dredger according to claim 1 or 2 , wherein the grab bucket is temporarily stopped at the descending speed switching position and the ascending speed switching position. The dredging method using the grab dredger according to any one of claims 1 to 3, wherein the descending and descending speed is set to 1/4 to 1/2 of the descending standard speed. The dredging method using the grab dredger according to any one of claims 1 to 4, wherein the descending speed switching position is 3 to 5 m from the bottom surface of the water. The dredging method using the grab dredger according to any one of claims 1 to 5, wherein the ascending speed is 1/4 to 1/2 of the ascending standard speed. The dredging method using the grab dredger according to any one of claims 1 to 6, wherein the ascending speed switching position is set to 1 to 3 m from the water bottom after the excavation.

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