System and method for supporting excavation of underwater ground

Abstract

To provide an excavation support system of a water bottom ground that can support efficient excavation by grasping states of a ground and a water flow of a water bottom in a planned range of excavation.SOLUTION: An excavation support system 1 comprises: an underwater sonar 4 that emits sound waves to a ground surface 12 to grasp a state of a water bottom in a predetermined range; a GPS 5 that is a positioning system that can grasp a position of a heavy excavation machine 2 on water; a machine guidance function 6 that can grasp a position of an attachment 21 of the heavy excavation machine 2; a flow velocity measurement portion 7 that can grasp a flow velocity in a construction water area; a display portion 8 that can display various information; and a control portion 9 that performs information processing. The control portion 9 can display a water depth of a measurement range 13, the position of the attachment 21 of the heavy excavation machine 2, and the flow velocity and a flow direction 16, on the display portion 8.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a system for supporting excavation of underwater ground. [Background technology]

[0002] Conventionally, one construction management method for excavating ground at the bottom of a body of water involves using data obtained by a three-dimensional sonar or the like to display a three-dimensional image of the bottom of the body of water and its surroundings, and constantly visually checking the image while working (see, for example, Patent Document 1). Another proposed method involves acquiring water depth information and backhoe attitude information, and superimposing the backhoe's operating status on the bottom topography of the body of water (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5565957 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-278158 Summary of the Invention [Problem to be solved by the invention]

[0004] While conventional methods can monitor the condition of the bottom of the water during excavation in real time and manage the finished shape, they do not take into account the water flow speed and direction.The water flow speed and direction change depending on the installation status of structures such as bridge pier foundations, water gates, quays, and temporary cofferdam steel pipe sheet piles, the distance from the structures, the progress of excavation, and other factors, and have a significant impact on the movement of soil and sand during excavation.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a system for supporting excavation of subsurface ground that can grasp the state of the subsurface ground and water flow in the planned excavation area and support efficient excavation. and a method for supporting excavation of underwater ground The purpose is to provide [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a first invention is an excavation support system for bottom ground, comprising an underwater sonar that emits sound waves to the ground surface to grasp the state of the bottom of a predetermined area, a positioning system that can grasp the position of an excavating machine on the water, a machine guidance function that can grasp the attachment position of the excavating machine, a flow velocity measurement unit that can grasp the flow velocity in the construction water area, a display unit that can display various information, and a control unit that processes information, wherein the control unit can display on the display unit the water depth in the measurement area, the attachment position of the excavating machine, the flow velocity and flow direction, and the flow velocity and flow direction at the position of the flow velocity measurement unit. and information on the bottom conditions. This is a waterbed excavation support system that calculates the flow velocity and flow direction of each part of the construction water area near the ground surface and displays them on the display unit. The second invention is a method for supporting excavation of waterbed ground, comprising an underwater sonar that emits sound waves to the ground surface to grasp the condition of the waterbed within a predetermined range, a positioning system that can grasp the position of an excavating machine on the water, a machine guidance function that can grasp the attachment position of the excavating machine, a flow rate measurement unit that can grasp the flow rate in the construction water area, a display unit that can display various information, and a control unit that processes information, wherein the control unit uses an excavation support system that can display the water depth within the measurement range, the attachment position of the excavating machine, and the flow rate and direction on the display unit, and determines the excavation order in the planned excavation range based on the condition of the waterbed and the flow rate and direction. The third invention is a method for supporting excavation of waterbed ground, comprising an underwater sonar that emits sound waves to the ground surface to grasp the condition of the waterbed within a predetermined range, a positioning system that can grasp the position of an excavating machine on the water, a machine guidance function that can grasp the attachment position of the excavating machine, a flow rate measurement unit that can grasp the flow rate in the construction water area, a display unit that can display various information, and a control unit that performs information processing, wherein the control unit uses an excavation support system that can display on the display unit the water depth within the measurement range, the attachment position of the excavating machine, the flow rate and flow direction, and the control unit identifies the type of object at each position on the waterbed from the reflection intensity of the sound waves from the underwater sonar and can display the object type on the display unit, and the attachment is selected based on the object type. A fourth invention is a method for supporting excavation of a water bottom, comprising: an underwater sonar that emits sound waves to the ground surface to grasp the state of the water bottom within a predetermined range; a positioning system that can grasp the position of an excavating machine on the water; a machine guidance function that can grasp the attachment position of the excavating machine; a flow velocity measuring unit that can grasp the flow velocity in the construction water area; a display unit that can display various information; and a control unit that processes information, wherein the control unit uses an excavation support system that can display the water depth within the measurement range, the attachment position of the excavating machine, and the flow velocity and flow direction on the display unit, and calculates the flow velocity from the flow velocity conditions in the construction water area. The flow rate is equal to or greater than a predetermined value, This is a method for supporting excavation of underwater ground, characterized by installing an independent submerged breakwater structure upstream of the water flow near the ground surface of the construction water area when it is expected that the operating rate of underwater excavation work will decrease. The fifth invention is a method for supporting excavation of waterbed ground, comprising an underwater sonar that emits sound waves to the ground surface to grasp the condition of the waterbed within a predetermined range, a positioning system that can grasp the position of an excavating machine on the water, a machine guidance function that can grasp the attachment position of the excavating machine, a flow rate measurement unit that can grasp the flow rate in the construction water area, a display unit that can display various information, a control unit that processes information, and a water sampling device arranged inside a support unit that reaches the ground surface, wherein the control unit uses an excavation support system that can display the water depth within the measurement range, the attachment position of the excavating machine, and the flow rate and flow direction on the display unit, and determines equipment that can be used as the underwater sonar or the flow rate measurement unit from the turbidity data from the water sampling device.

[0007] According to the present invention, the control unit processes various information and displays it on the display unit, so that the condition of the ground at the bottom of the water, the speed and direction of the water current, and the attachment position of the excavator can be grasped in real time. As a result, the excavation order of the planned excavation area can be determined so that excavation can be carried out efficiently, taking into account the speed and direction of the water current.

[0008] In a third aspect of the present invention, when the bottom of the water is made of normal sediment, the attachment is a bucket, The control unit The flow velocity and direction Depending on In the bucket Amount excavated at one time and the direction of the cutting edge of the bucket Set do It is desirable. This allows the appropriate amount of excavation to be performed according to the flow rate, preventing incomplete excavation or spillage from the bucket.

[0009] In the third invention, The control unit can identify the type of object at each position on the bottom of the water from the reflection intensity of the sound waves from the underwater sonar and display the type of object on the display unit. do. In this case, the control unit may be capable of determining whether or not excavation is possible based on the type and size of the object, and displaying information on whether or not excavation is possible on the display unit. If the display can show the type of object, it will be possible to grasp the presence of objects other than sand and soil in real time. Also, if the display shows whether the object can be excavated or not, it will be possible to select the most suitable attachment for the object removal work.

[0010] In the second invention, The control unit compares the scour prediction unit and the deposition prediction unit in the ground with preset scour conditions and deposition conditions, and determines the scour prediction unit and the deposition prediction unit in the ground. hand Display on the display unit and determine the drilling sequence so that the excavation is carried out while scouring. It is desirable. This allows the order of excavation in the planned excavation area to be appropriately determined taking into account the movement of soil and sand due to water currents.

[0011] The underwater sonar is preferably a multi-beam sonar, and is capable of switching measurement waves depending on the degree of turbidity of the water area where the work is being carried out. This allows the measurement accuracy to be improved depending on the turbidity.

[0012] When carrying out construction work on a river, it is desirable that the control unit be able to predict future changes in water level by acquiring the amount of precipitation upstream of the river and comparing it with pre-stored conditions. This allows changes in water depth to be detected in advance and a decision made as to whether construction can continue or not. [Effects of the Invention]

[0013] According to the present invention, a system for supporting excavation of submerged ground can be provided that can support efficient excavation by grasping the conditions of the submerged ground and water flow in the planned excavation area. and a method for supporting excavation of underwater ground can provide. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram showing the configuration of an excavation support system 1. FIG. [Figure 2] FIG. 2 is a block diagram showing the functions of the excavation support system 1. [Figure 3] (a) is a plan view showing the condition of the ground surface 12, the water flow, and the position of the attachment 21, and (b) is a cross-sectional view taken along line AA in (a). [Figure 4] FIG. [Figure 5] A plan view showing information on the water flow in each part and predicted deformation of the ground surface 12. [Figure 6] FIG. 3 is a diagram showing an example of information processing by the control unit 9. [Figure 7] (a) is a plan view of the area around excavation site 14, and (b) is a cross-section taken along line BB in (a). [Figure 8] (a) is a plan view of the area around excavation site 14, and (b) is a cross-section taken along line CC in (a). [Figure 9] 1A is an elevation view of the vicinity of the flow velocity measurement unit 7a, and FIG. 1B is a diagram showing an example of the display on the display unit 8. FIG. [Figure 10] (a) is a diagram showing the self-supporting submerged breakwater 23a, and (b) is a diagram showing the self-supporting submerged breakwater 23b. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the configuration of an excavation support system 1, and FIG. 2 is a block diagram showing the functions of the excavation support system 1. As shown in FIG.

[0016] As shown in Figure 1, the excavation support system 1 is used when dredging work is carried out on the ground 3 at the bottom of a body of water, such as a riverbed, using an excavation machine 2 installed on a barge 22. The excavation support system 1 comprises an underwater sonar 4, a GPS 5 positioning system, a machine guidance function 6, a flow velocity measurement unit 7, a display unit 8, a control unit 9, etc.

[0017] The underwater sonar 4 emits sound waves toward the ground surface 12 to grasp the condition of the bottom of the water in the measurement range 13. The underwater sonar 4 is a multi-beam sonar with a horizontal and vertical oscillating mechanism. It is desirable for the underwater sonar 4 to be able to switch between CW and FM chirp waves depending on the level of turbidity in the construction waters. While CW waves are typically used, FM chirp waves can be used in the presence of highly turbid water bodies to enable highly accurate measurements over long distances. Furthermore, if the underwater current speed 11 does not exceed 1 knot (approximately 0.5 m / s) and the underwater drone's position can be controlled using a thruster, an underwater acoustic camera mounted on the underwater drone can be used as the underwater sonar 4. This allows for accurate measurement of relatively localized bottom topography. The suitability of using an underwater drone is determined based on the actual current speed measured by the current speed measurement unit 7, which will be described later.

[0018] The GPS 5 can determine the position of the excavator 2 on the water. Note that the positioning system is not limited to the GPS 5, and other satellite positioning systems (GNSS) or total stations may also be used. By installing multiple total stations (surveying instruments) at points where the coordinates on land are known and installing an automatic tracking mirror on the side of the barge 22 (moving object), the position and direction of the excavator 2 can be determined.

[0019] The machine guidance function 6 consists of multiple inclinometers 61 attached to the boom 23, and is capable of grasping the position of the attachment 21 of the excavator 2. The attachment 21 is attached to the tip of the boom 23 and can be changed depending on the application. When excavating normal soil and sand, a bucket as shown in Figure 1 is attached to the boom 23 as the attachment 21, but this can be changed to a breaker when crushing concrete, a gripper or grabber when processing sunken wood, or a road header or drum cutter when excavating bedrock.

[0020] The flow velocity measurement unit 7 can grasp the flow velocity in the construction water area. The construction water area refers to the entire underwater area 11 above the planned excavation area of ​​the ground 3, and the flow velocity measurement unit 7 is installed in at least one location in the construction water area. The flow velocity measurement unit 7 is attached, for example, to a support unit 71 that reaches the ground surface 12 and grasps the flow velocity near the ground surface 12. The flow velocity measurement unit 7 is not limited to the example shown in the figure and may be installed separately from the barge 22. It may also directly measure the water flow velocity using various sensors or measure the water flow rate and convert it to flow velocity. The support unit 71 may be, for example, a hollow pipe, and a current meter or sensor cord may be installed inside. Furthermore, a micro-submersible pump (a water sampling pump or hose for measuring turbidity near the bottom of the water) may be installed inside the support unit 71 to measure the turbidity of the underwater area 11. From the flow velocity data from the flow velocity measurement unit 7 and the turbidity data from the micro-submersible pump, it is possible to determine whether the above-mentioned underwater drone or other precise flow meter can be used. The support part 71 is also used to measure water depth.

[0021] As shown in FIG. 2, the control unit 9 is connected to the underwater sonar 4, GPS 5, machine guidance function 6, and current velocity measurement unit 7 via wired or wireless connections, and acquires and processes information from each device. The control unit 9 displays the water depth within the measurement range 13, the position of the attachment 21 of the excavator 2, and information on the current velocity and direction on the display unit 8. The display unit 8 and the control unit 9 may be integrated into one unit, such as a PC 10, or may be separate units connected via wired or wireless connections. The display unit 8 may be provided in multiple locations, and the displayed content may be viewable from within the cabin of the excavator 2. The data acquired from each device and the data processed by the control unit 9 are stored on a cloud server (not shown) via on-site Wi-Fi and can be viewed off-site.

[0022] 3 to 5 show examples of display on the display unit 8, and FIG. 6 shows an example of information processing by the control unit 9. When the excavator 2 excavates the ground 3 at the bottom of the water, the control unit 9 in the excavation support system 1 obtains information on the condition of the ground 3 at the bottom of the water within the measurement range 13 from the underwater sonar 4, information on the water flow from the current velocity measurement unit 7, and information on the position of the attachment 21 from the GPS 5 and the machine guidance function 6 (S101). Based on this information, the display unit 8 displays the water depth of the ground surface 12 within the measurement range 13, the flow velocity and flow direction 16 at the position of the current velocity measurement unit 7, and the position of the attachment 21 (S102, FIG. 3). Note that when the water depth at the position of the current velocity measurement unit 7 is measured by the support unit 71, the control unit 9 may correct the water depth obtained from the information from the underwater sonar 4 by comparing it with the value measured by the support unit 71. The method of displaying the water depth of the ground surface 12 is not limited to the example shown in Fig. 3, and the water depth may be displayed by color coding, or the shape of the ground surface 12 may be displayed three-dimensionally using a bird's-eye view or the like. As for the flow direction, it is also possible to display not only the planar flow direction, but also the flow direction of the depth component, for example, by displaying a bird's-eye view or a predetermined or greater upward or downward flow using color or the like.

[0023] After S101, the control unit 9 may identify the type of object present on the ground surface 12, such as concrete blocks, gravel, boulders, sunken wood, driftwood, etc., from information on the reflection intensity of sound waves from the underwater sonar 4, and display the type of object 15 and whether or not it can be excavated on the display unit 8 (S103, Figure 4). Note that the method of displaying the type of object 15 is not limited to the example shown in Figure 3, etc., and a display method that distinguishes hard objects (stones, concrete blocks, etc.) from soft objects (earth and sand, etc.) by color may also be used. The size, specific gravity, etc. of the object 15 may also be displayed.

[0024] After S101, the control unit 9 may estimate the flow velocity and flow direction 16a in each part of the construction water area from the condition of the ground 3 at the bottom of the water and information on the flow velocity and flow direction 16, and display it on the display unit 8 (S102', Figure 5). In S102', for example, the flow velocity and flow direction 16 at the position of the flow velocity measurement unit 7 are input as representative values ​​of the water flow based on the condition of the ground 3 at the bottom of the water, and the flow velocity and flow direction 16a in each part of the construction water area near the ground surface 12 are calculated using FEM or the like. By calculating and displaying the flow velocity and flow direction 16a in detail, it is possible to estimate the upward and downward flow in each part, as well as the occurrence of vortices, etc.

[0025] After S102 or S102', the control unit 9 may set the amount of excavation of the ground 3 to be excavated at one time with the bucket, and display this on the display unit 8 (S104). The amount of excavation of the ground 3 is set according to the flow velocity and flow direction 16 at the position of the flow velocity measurement unit 7 and the estimated flow velocity and flow direction 16a at each point. If the flow velocity is high, spillage of the excavated soil from the bucket can be prevented by setting a small amount of excavation to be done at one time. In addition, the direction of the bucket cutting edge may be set according to the flow direction, and the excavation direction may be set in a direction that is less likely to cause spillage from the bucket.

[0026] After S102 or S102', the control unit 9 may compare information such as the state of the ground 3 at the bottom of the water, the flow velocity and flow direction 16 at the position of the flow velocity measurement unit 7, and the estimated flow velocity and flow direction 16a at each part with preset scouring and deposition conditions to determine the scouring prediction unit 17 and the deposition prediction unit 18 for the ground 3, and display the results on the display unit 8 (S105, FIG. 5). In S105, for example, simulations using several water flows are performed in advance to set conditions (flow velocity and flow direction) under which scouring or deposition is predicted as scouring and deposition conditions, and the scouring prediction unit 17 and the deposition prediction unit 18 may be determined by comparing the conditions with the flow velocity and flow direction at the location where scouring or deposition is likely to occur, calculated from the various information above. Alternatively, the water flow conditions in vortex generation areas where scouring is likely to occur and stagnation generation areas where deposition is likely to occur, may be set as scouring and deposition conditions, and the scouring prediction unit 17 and the deposition prediction unit 18 may be determined by comparing the conditions with the various information above. Furthermore, the possibility of scouring or deposition occurring for various water flows may be matrixed according to the shape and size of the object 15, and the scouring prediction unit 17 or deposition prediction unit 18 may determine the part that meets the conditions.

[0027] When the excavation support system 1 is used to excavate the ground 3, information on the state of the ground 3 at the bottom of the water, as well as flow speed and flow direction 16, is obtained in real time in S101 and S102, and the excavation order for the planned excavation area is determined. When S102' and S105 are performed, the flow speed and flow direction 16a of each part shown in Figure 5 and the positions of the scouring prediction unit 17 and the deposition prediction unit 18 are also taken into consideration. When excavating, information on whether the object 15 can be excavated (S103) and the amount of excavation to be performed at one time (S104) are also taken into consideration. For example, if the ground surface 12 contains a mixture of sand and boulders, stirring the mixture at the bottom of the water after excavation will allow the lighter sand to flow downstream, leaving only the heavier boulders, thereby reducing the amount of soil to be lifted.

[0028] Figures 7 and 8 are diagrams showing changes in the water flow and the water bottom. When excavation site 14 is set parallel to the water flow as shown in Figure 7(a), if excavation site 14 is excavated in a trench shape as shown in Figure 7(b), the flow velocity is faster in the shallow parts than in the deep parts, resulting in scouring areas 17a on both sides of the trench and deposits 18a at the bottom of the trench. When excavation site 14 is set perpendicular to the water flow as shown in Figure 8(a), if excavation site 14 is excavated in a trench shape as shown in Figure 8(b), scouring area 17a occurs on the upstream side of the trench and deposits 18a occur downstream of the trench bottom. Scouring area 17a, which is smaller than the upstream side, occurs on the downstream side of the trench, and the sediment is washed downstream.

[0029] When determining the excavation sequence for the planned excavation area, knowledge about water flow and changes in the water bottom, as shown in Figures 7 and 8, is also taken into consideration. This makes it possible to achieve efficient excavation by utilizing water flow, such as by excavating while scouring, excavating without backfilling, or excavating while depositing. For example, while excavated soil is normally lifted above the water surface, if the excavation location 14 is perpendicular to the water flow as shown in Figure 8, the amount of soil lifted can be reduced by excavating from upstream to downstream and flushing away the soil from the scoured area 17a on the downstream side.

[0030] The state of the ground 3 at the bottom of the water, the flow velocity and the flow direction 16 determined in S101 and S102 may be fed back to the simulation and used in calculations to predict the future water flow and state of the ground 3 at the bottom of the water as excavation continues. In this case, excavation work is carried out while understanding both the predicted state of the ground 3 and the actual state of the ground 3. In other words, the actual ground conditions are constantly updated by the underwater sonar, and predictions of future ground changes and optimal excavation conditions are also updated accordingly.

[0031] While the excavation support system 1 is being used to excavate the ground 3, the control unit 9 may be able to acquire the amount of precipitation upstream of the river. The control unit 9 compares the amount of precipitation upstream of the river with pre-stored conditions to predict future changes in water levels within the construction area. This allows a decision to stop excavation in advance if there are signs of a dangerous change in water level in a few hours.

[0032] In this way, the excavation support system 1 of the first embodiment uses information from the underwater sonar 4, GPS 5, and machine guidance function 6 to display the actual state of the ground 3 at the bottom of the water (water depth and the presence of objects 15 other than sand) and the position of the attachment 21 in real time on the display unit 8 while the ground 3 is being excavated, allowing the worker to check this information while proceeding with the excavation. In addition, when the presence of an object 15 is recognized, the type and information on whether excavation is possible are displayed, allowing the worker to select the optimal attachment 21 for removing each object 15.

[0033] In the excavation support system 1, by using information from the flow velocity measurement unit 7, the water flow velocity and direction 16 can be displayed in real time on the display unit 8 while the ground is being excavated. This makes it possible to grasp changes in the flow velocity and direction 16 due to the installation status of various structures, the distance to the structures, deformation of the ground surface 12 as the excavation progresses, etc., along with the condition of the ground 3 during excavation, and to determine the excavation order for the planned excavation area to be excavated efficiently. In addition, by setting the amount of ground 3 to be excavated at one time according to the water flow condition, it is possible to set an appropriate excavation amount and prevent leaving any material unexcavated or spilling from the bucket.

[0034] In the excavation support system 1, the scouring prediction unit 17 and the deposition prediction unit 18 in the ground 3 can be determined based on the flow velocity and flow direction 16 and the state of the ground 3 at the bottom of the water, and can display the results on the display unit. This allows the order of excavation to be appropriately determined taking into account the movement of sediment.

[0035] Although the flow velocity measurement unit 7 is installed only near the ground surface 12 in the example shown in FIG. 1 , the arrangement of the flow velocity measurement unit 7 is not limited to this. FIG. 9 shows an example in which multiple flow velocity measurement units 7a are installed. The construction water area shown in FIG. 9 is in harsh conditions, with turbid water 19 and backflow from offshore to upstream due to swells, etc. Under such conditions, multiple flow velocity measurement units 7a may be installed and multiple flow velocities and flow directions 16 may be displayed on the display unit 8. In the example shown in FIG. 9 , three flow velocity measurement units 7a-1, 7a-2, and 7a-3 are installed near the ground surface 12, near the center of the water depth, and near the water surface, respectively. The control unit 9 acquires water flow information at three depth locations and displays the flow velocities and flow directions 16-1, 16-2, and 16-3 on the display unit 8. The control unit 9 may also calculate the flow velocity distribution and display it on the display unit 8.

[0036] The flow velocity measurement unit 7a is composed of, for example, an extension section 73 connected to a support section 71 and a sphere 72 connected to the tip of the extension section 73. The support section 71 is suspended by a hanging member 76, and heavy snowshoes 74 are attached to its lower end to prevent movement due to water currents. The connection between the snowshoes 74 and the support section 71 is designed to be able to follow the slope of the underwater topography to some extent. As an alternative to snowshoes 74, a disk-shaped member similar to a ski pole may be attached near the lower end of the support section 71, with the underside of the disk-shaped member penetrating into the ground 3 at the bottom of the water to prevent movement due to water currents. In addition, by attaching a GPS 75 to the upper end, the absolute coordinates of the ground surface 12 can be measured using the length of the support section 71 and the position information from the GPS 75, and the water depth can be constantly determined, even when the water level fluctuates significantly, and compared with the measurement value measured by the underwater sonar 4.

[0037] The specific gravity of the sphere 72 is adjusted to be approximately the same as that of the turbid water in the construction water area. The expandable portion 73 is made of rubber, spring, or the like, with the relationship between flow velocity and extension calibrated in advance, and is durable and has resilience. The flow velocity measurement portion 7a measures the flow velocity and direction 16 of the water current from the extension amount and direction of extension of the expandable portion 73 when the sphere 72 moves with the water current. The flow velocity measurement portion 7a is inexpensive and easy to replace in the event of a malfunction. The flow velocity measurement portion 7a can be used in both freshwater and saltwater areas by adjusting the specific gravity of the sphere 72 to match the water in the construction water area. The method for measuring the flow velocity and direction at each water depth is not particularly limited.

[0038] Furthermore, when the flow velocity conditions in the construction water area are expected to be severe over the long term and the availability of underwater excavation work is expected to drop significantly, a self-supporting submerged mound structure may be temporarily installed on the ground 3. Figure 10 shows an example of a self-supporting submerged mound. The self-supporting submerged mound 23a shown in Figure 10(a) has a perforated membrane 25, such as a silt fence, installed between a floating pipe 24 and an H-beam 26, while the self-supporting submerged mound 23b shown in Figure 10(b) has a frame 29 with a perforated plate 28. By installing the self-supporting submerged mounds 23a and 23b upstream of the water flow near the ground surface 12 of the construction water area, the water flow passes through the perforated membrane 25 and the perforated plate 28 and flows into the construction water area at a reduced speed, facilitating excavation work. The self-supporting submerged mounds 23a and 23b are equipped with a hoisting rope 27 and a hoisting hook 30, and are installed and removed using a lifting device (not shown). If the lifting hook 30 is attached to a float and left above the water surface, the self-supporting submerged breakwaters 23a and 23b can be easily removed after the excavation work is completed.

[0039] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas disclosed in this application, and it is understood that these modifications and alterations also fall within the technical scope of the present invention.

[0040] For example, in the embodiment, dredging work on the ground 3 at the bottom of a river is taken as an example, but the excavation support system 1 can also be used to support excavation of ground at the bottom of a body of water other than a riverbed. [Explanation of symbols]

[0041] 1. Excavation support system 2...Excavator 3......ground 4. Underwater sonar 5, 75...GPS 6...Machine guidance function 7, 7a, 7a-1, 7a-2, 7a-3……Flow velocity measuring section 8……Display section 9...Control unit 10...PC 11……Underwater 12……Ground surface 13...Measuring range 14... Excavation location 15……object 16, 16-1, 16-2, 16-3, 16a... Flow velocity and direction 17...Scouring prediction section 17a……Scouring part 18. Accumulation prediction section 18a……Deposition part 19...Muddy 21...Attachment 22……Barge 23...Standing submerged breakwater 24...Floating pipe 25...Perforated membrane 26……H steel 27....Hanging rope 28...Perforated board 29……Frame body 30....Hanging hook 61……Inclinometer 71……Support part 72...sphere 73……Extendable part 74...Snowshoes 76... Hanging member

Claims

1. A subsurface excavation support system, comprising: An underwater sonar that emits sound waves on the ground surface to grasp the condition of the bottom of a specified area; A positioning system that can grasp the position of excavation machinery on the water, a machine guidance function capable of grasping the attachment position of the excavator; A flow velocity measuring unit capable of grasping the flow velocity in the construction water area; A display unit capable of displaying various types of information; a control unit that processes information; Equipped with The control unit is capable of displaying the water depth in the measurement range, the attachment position of the excavation machine, and the flow velocity and flow direction on the display unit, and is characterized in that the control unit calculates the flow velocity and flow direction of each part of the construction water area near the ground surface from the flow velocity and flow direction at the position of the flow velocity measurement unit and information on the state of the water bottom, and displays them on the display unit.

2. A method for supporting excavation of underwater ground, comprising: An underwater sonar that emits sound waves on the ground surface to grasp the condition of the bottom of a specified area; A positioning system that can grasp the position of excavation machinery on the water, a machine guidance function capable of grasping the attachment position of the excavator; A flow velocity measuring unit capable of grasping the flow velocity in the construction water area; A display unit capable of displaying various types of information; a control unit that processes information; Equipped with The control unit uses an excavation support system that can display the water depth in the measurement range, the attachment position of the excavator, and the flow velocity and flow direction on the display unit, A method for supporting excavation of submerged ground, characterized in that the excavation order in the planned excavation area is determined based on the state of the submerged ground and the flow velocity and direction.

3. An excavation support method for submerged ground as described in claim 2, characterized in that the control unit compares the scouring prediction section and the deposition prediction section in the ground with preset scouring conditions and deposition conditions, determines the scouring prediction section and the deposition prediction section in the ground, displays them on the display unit, and determines the excavation order so that excavation occurs while scouring occurs.

4. A method for supporting excavation of underwater ground, comprising: An underwater sonar that emits sound waves on the ground surface to grasp the condition of the bottom of a specified area; A positioning system that can grasp the position of excavation machinery on the water, a machine guidance function capable of grasping the attachment position of the excavator; A flow velocity measuring unit capable of grasping the flow velocity in the construction water area; A display unit capable of displaying various types of information; a control unit that processes information; Equipped with The control unit uses an excavation support system that can display the water depth in the measurement range, the attachment position of the excavator, and the flow velocity and flow direction on the display unit, The control unit is capable of identifying the type of object at each position on the bottom of the water from the reflection intensity of the sound waves of the underwater sonar and displaying the type of object on the display unit, A method for supporting excavation of a submerged ground, characterized in that an attachment is selected based on the object type.

5. When the bottom of the water is made of normal sediment, the attachment is a bucket. The method for supporting excavation of submerged ground according to claim 4, characterized in that the control unit sets the amount of ground to be excavated at one time by the bucket and the direction of the bucket blade tip according to the flow velocity and flow direction.

6. A method for supporting excavation of underwater ground, comprising: An underwater sonar that emits sound waves on the ground surface to grasp the condition of the bottom of a specified area; A positioning system that can grasp the position of excavation machinery on the water, a machine guidance function capable of grasping the attachment position of the excavator; A flow velocity measuring unit capable of grasping the flow velocity in the construction water area; A display unit capable of displaying various types of information; a control unit that processes information; Equipped with The control unit uses an excavation support system that can display the water depth in the measurement range, the attachment position of the excavator, and the flow velocity and flow direction on the display unit, A method for supporting excavation of underwater ground, characterized by installing an independent submerged breakwater structure upstream of the water flow near the ground surface of the construction water area when the flow velocity conditions in the construction water area indicate that the flow velocity is above a predetermined level and it is expected that the operating rate of underwater excavation work will decrease.

7. A method for supporting excavation of underwater ground, comprising: An underwater sonar that emits sound waves on the ground surface to grasp the condition of the bottom of a specified area; A positioning system that can grasp the position of excavation machinery on the water, a machine guidance function capable of grasping the attachment position of the excavator; A flow velocity measuring unit capable of grasping the flow velocity in the construction water area; A display unit capable of displaying various types of information; a control unit that processes information; a water sampling device disposed inside a support portion that reaches the ground surface; Equipped with The control unit uses an excavation support system that can display the water depth in the measurement range, the attachment position of the excavator, and the flow velocity and flow direction on the display unit, A method for supporting excavation of waterbed ground, characterized in that equipment that can be used as the underwater sonar or the flow velocity measurement unit is determined from turbidity data obtained by the water sampling device.

8. A method for supporting excavation of bottom ground as described in any of claims 2 to 7, characterized in that the flow velocity measuring unit capable of grasping the flow velocity near the ground in the construction water area is attached to a support unit that reaches the ground surface.

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