JPH045095B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an installation direction control device for underwater objects, such as a caisson or a large artificial reef, for controlling the direction of the underwater structures when the objects are suspended and installed. (Prior Art) Conventionally, in the installation of concrete caissons for submarine structures in deep water areas, artificial reefs, and other sunken structures, the sunken objects are generally moved by cranes on the water.
A hanging frame device is used to lower the vessel into the sea. (Problems to be Solved by the Invention) With such conventional devices, especially when submerging objects in deep waters, it is difficult to install the submerged object in an accurate position because it is affected by tidal currents. In view of these problems, the present invention provides a device for controlling the installation direction of underwater objects, which is capable of stably suspending objects in a desired direction and installing them at accurate positions even in the presence of tidal currents. It is intended for the purpose of providing. (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention is provided with a hanging frame that is generally used in submerging caissons, large artificial reefs, etc., and the hanging frame is provided with an adjustable angle. It was equipped with a rudder to control the direction of suspended objects. (Function) This installation direction control device for underwater objects suspends an underwater object below the hanging frame, and when it is lowered into the sea using a crane, the rudder adjusts to the current and maintains a constant position. Stable in the direction of. Therefore, it is necessary to determine the direction of the rudder relative to the sunken object by assuming in advance the direction in which it will be stabilized, or to attach a drive mechanism for direction adjustment to the rudder, and to change the direction of the rudder in the tidal current to suspend the object. By adjusting the frame to the desired orientation, the orientation of the underwater objects under the hanging frame is controlled. (Example) Next, an example of implementation of the present invention will be described with reference to the drawings. This device has a hanging frame 1 framed in a rectangular shape. This hanging frame 1 has hanging wires 2 connected to the four corners of its upper surface, and is suspended by hooking the hanging hook of a crane onto the wires 2. On the other hand, on the lower surface of the hanging frame 1, the upper ends of the suspended object hanging wires 4, 4, . A rudder 5 is attached to the lower surface of the hanging frame 1 so that its horizontal direction can be changed around a vertical shaft 6. The direction of the rudder 5 is changed by an electric rotating machine 7 installed on the hanging frame 1. For example, the rotating machine 7 has a built-in compass and a potentiometer (rotation angle detector), and detects the amount of variation between the direction of the compass and the orientation of the hanging frame using the potentiometer, Accordingly, the rotating machine 7 is driven, and the direction of the rudder 5 is adjusted by the action of the tidal current so that the suspension frame 1 is at a constant angle with respect to the direction indicated by the compass. A counterweight 8 is attached to the front end of the rudder 5 so that the center of gravity of the entire rudder 5 is located at the vertical axis 6. Furthermore, the front end of the rudder 5 is equipped with a current velocity meter so that the flow velocity at the sinking position can be adjusted. When using this device, for example, see Figures 2 and 3.
As shown in the figure, a crane ship 10 is used, and the lifting hook 12a at the tip of the winding wire 12 of the crane 11 provided on the crane ship 10 is hung on the lifting wire 2 of the hanging frame 1, and the hanging hook 12a is suspended. An anchor ring 1 in which the suspended object hanging wires 4, 4, .
3, 13... to suspend and hold the deposited object A ₁ (or A ₂ ). In this way, the winding wire 1 of the crane 11 is
2, the suspended object A ₁ is lowered together with the hanging frame 1, and the direction of the hanging frame 1 at the time of settling is measured based on the direction by the compass and the value of the potentiometer, and the direction of the rudder 5 is determined based on this. Adjust to orient the deposit _A1 in the desired direction. This control of the direction of the sunken object can be done, for example, as shown in Figure 4A.
When you want to line up A ₂ along the submergence normal line NW on the seabed, for example, if the tidal current direction is a, point the rudder 5 in the direction a and set the center line direction of the submerged object A ₂ at that time to the submersion method. Adjust the angle of both so that it follows the line. In other words, as shown in Figure 4 (b), the current normal line NW
is an angle of -45 degrees with respect to the direction N, and if the value of the direction indicator of the rudder 5 is θ'a with respect to N, then the direction of the center line of the deposited object A is aligned with the normal NW. The angle θa of No. 5 is controlled so that θa = θ′a + 45°. In addition, although the above-mentioned embodiment is equipped with an electric drive mechanism and a measuring device and adjusts the angle during the descent, the present invention also allows for manually adjusting the angle of the rudder before descent. It may be adjusted according to the direction of the tidal current, and after being suspended, the operation is simply performed to lower it to a predetermined lowering position. Next, a test example of the device of the present invention will be explained. (1) Flow direction adaptation characteristic test The conditions for the original submerged object and its corresponding model scale are shown in Table 1, and as shown in Figure 5 A and B, only the block model A ₁ without a rudder, and the vertical A rudder 5 with a size of 7 cm x 20 cm was attached, and each was suspended in a water stream. At this time, the model with only model _A1 vibrated gently within an angle range of approximately ±20° with the side wall facing the flow, whereas the model with rudder 5 vibrated slowly within an angle range of approximately ±2° with respect to the flow. It remained stationary throughout the range with almost no vibration.

[Table] The cause of the vibration in the case of only model _A1 is that the strength of the peeling vortex (this is called a Karman vortex) that occurs in the trailing region of the block becomes stronger alternately on the left and right sides of the block. This is because they become weaker and weaker. On the other hand, when a rudder is used, the block is considered to be stationary because the moment of adapting to the flow due to the rudder is sufficiently larger than the rotational moment of the block due to the Karman vortex. (2) Test regarding rudder size The model shown in Table 1 above in the state shown in Figure 5 B
Experiments were conducted by attaching rudders of various sizes shown in Table 2 to A ₁ and suspending them into flowing water.

[Table] As a result, the larger the area of the rudder, the smaller the vibration angle caused by the Karman vortex. The vibration phenomenon seems to be related to the shape and dimensions of the suspended object, so the area of the rudder is the area of the model's shadow (in this case, 10 x 10 = 100 cm ² ).
The results are shown in FIG. As is clear from the figure, if the area of the rudder is set to be at least 1.5 times the drift area of the object to be sunk,
The rudder follows the direction of the current, and vibrations can be prevented. From the results of the experiments described above, it has become clear that the following points need to be taken into consideration when implementing the present invention. (1) The scale of the rudder is 1.5 of the drift area of the submerged object.
It seems necessary and sufficient to set it to about twice the size. However, even if the area is 1.5 times larger, it is not realistic to have a shape that is extremely long both vertically and horizontally, and it is more preferable to use a rectangular shape that is long horizontally. (2) The weight of the sunken object does not affect the accuracy of the rudder's adaptation to the flow; it only takes time to adapt. (3) Flow speed also has little effect on the rudder's adaptation accuracy; the slower the flow velocity, the longer it takes to adapt. (Effects of the Invention) The installation direction control device for underwater objects according to the present invention is configured as described above, and the underwater objects are suspended and supported at the bottom, and a direction rudder is attached to the hanging frame to be raised and lowered by a crane or the like, and the angle can be adjusted freely. By installing this, the angle of the suspension frame and, ultimately, the underwater objects relative to the tidal current can be controlled, making it easy to control the orientation of the objects in areas with fast currents.
It has become something that can be done in a stable state.

[Brief explanation of drawings]

The drawings show an example of the implementation of the present invention, and FIG. 1A is a plan view showing the entire device, FIG. 1B is a side view of the same, FIG. 1C is a front view of the same, and FIG. 3 is a perspective view of another example, and FIG. 4 shows the direction control state at the time of installation. 5
Figures A and B are plan views of the flow direction adaptation characteristic test conditions, No. 6
The figure is a graph showing the test results regarding the size of the rudder. A ₁ , A ₂ ... sunken object, 1 ... hanging frame, 2 ... wire, 4 ... sunken object suspension wire, 5 ... rudder, 6 ... vertical axis, 7 ... rotary machine.

Claims (1)

[Scope of Claims] 1. A hanging frame for suspending underwater objects such as caissons and large artificial reefs is provided, and the hanging frame is equipped with a rudder whose angle can be freely adjusted so as to control the direction of the suspended objects. A device for controlling the installation direction of underwater objects. 2. A method for installing an underwater structure according to claim 1, wherein the rudder is adjustable according to the tidal current.