JP3388385B2 - Method and apparatus for filling underwater pipes below pipe - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for laying a water bottom laying pipe body laid on the sea floor for use as, for example, a cooling water supply / drainage channel in a thermal power plant.

[0002]

2. Description of the Related Art Conventionally, when laying the bottom of a pipe of this type, a trench is excavated and formed on the seabed at the laying position using a dredger, etc., and after the necessary ground treatment, support for sleepers, etc. Install the water bottom laying pipe at a distance from the bottom of the groove through the material,
After that, the groove is filled with a backfill material, and the pipe body is buried in the water bottom.

[0003]

In such a conventional laying method, the backfill material is dropped from above the water surface to fill the groove in which the pipe body is installed. Therefore, the repose angle at the time of stacking the backfill material If it is large, only by dropping from above the water surface, as shown in FIG. 7, there is a gap between the surface of the backfill material dropped from both sides of the pipe and the bottom face of the pipe, and it is not possible to lower the pipe sufficiently. There was a problem that it could not be filled correctly.

For this reason, conventionally, it is necessary to make a large gap between the bottom surface of the groove for laying the pipe body and the bottom surface of the pipe body to be installed so that the backfill material can easily enter under the pipe body. It is necessary to make the groove to be excavated on the bottom of the water deep,
There was a problem that the cost for excavation and backfilling would be large.

However, since it cannot be expected to completely fill the pipe under the pipe, conventionally, it is not expected to support the pipe by the backfill material under the pipe, and the wall pressure of the pipe is increased to increase the pipe strength. Therefore, there is a problem that the manufacturing cost of the pipe body becomes large.

The present invention has been made in view of such conventional problems.
Complete gap filling can be done without taking a large gap under the laying pipe body, no deep groove for pipe laying is required, and moreover,
It is an object of the present invention to provide a method and apparatus for filling a bottom of a water-bottom laid pipe under a pipe, which can receive a load of the pipe with a backfill material and can reduce the wall pressure of the pipe.

[0007]

The features of the method of the present invention for solving the above-mentioned conventional problems and for achieving the intended object are that the recess is formed in a pipe laying groove formed by excavation on the water bottom. In the method of filling the bottom of the water bottom laying pipe with the backfilling material, which is installed at a distance from the bottom of the groove, the backfilling material such as crushed stone and / or sand on land or on board. The slurry is mixed with water to form a slurry, the slurry is sent to a side portion of the water bottom laying pipe through a carrying pipe, and the slurry is jetted toward the bottom of the water laying pipe by opening the opening of the carrying pipe. It is to fill the return material under the water bottom laying pipe.

Incidentally, a backfill material is put into the concave groove on one side of the water bottom laying pipe installed in the pipe laying groove to close one side of the gap under the laying pipe, After that, it is preferable to inject the slurry into the gap below the water bottom laying pipe from the other side to fill the backfill material under the water bottom laying pipe, and as the backfill material, single-grain crushed stone and / or The use of sand is preferred.

The features of the apparatus of the present invention are that crushed stone and / or
Alternatively, a storage tank that contains a backfill material such as sand, and water is poured into the storage tank to form a slurry, a transfer unit for transferring the slurry in the storage tank to a water bottom through a transfer pipe, and a tip of the transfer pipe of the transfer unit The present invention resides in a sub-bottom filling device for a water bottom laying pipe body, which is connected to the bottom of the water and is installed on the bottom of the water by a weight, and has a slurry injection nozzle for injecting the slurry sent through the transfer pipe at a predetermined angle.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an apparatus used in the method of the present invention. In the figure, 1 is a groove for pipe laying, which is formed by excavating and forming on a water bottom.
Is a water bottom laying pipe installed on the pillow-shaped support member 3 at the bottom of the groove 1.

As a device for filling the gap a between the pipes 2, a soil carrier 6 having a storage tank 5 for loading the backfill material 4 and the backfill material in the storage tank 5 are made into a slurry to form a water bottom. And a slurry injection nozzle 8 for injecting the conveyed slurry toward the gap a below the pipe body 2. In the storage tank, the loaded backfill material 4 is Seawater is pumped up and injected by the submersible pump 10, and the transport means 7 has a sand pump 11 and a transport pipe 12. The sand pump 11 sucks the backfill material 4 in the storage tank 5 together with water to form a slurry. None carrier tube 12
I try to move inside.

The slurry injection nozzle 8 is connected to the lower end of the transfer pipe 12 and is held at a predetermined position on the water bottom by a weight 13. The vertical and horizontal angles of the slurry injection port are predetermined angles. It is fixed against the weight so as to maintain.

Next, a pipe filling method using the apparatus thus constructed will be described.

As shown in FIG. 2, after the pipe body 2 is installed in the concave groove 1 formed by excavation at the bottom of the water through the support member 3, first, a bucket or the like is formed in the concave groove 1 on one side of the pipe body 2. The backfilling material 4 is put in using a normal dropping device, and one side of the gap a under the pipe body 2 is closed as shown in FIG. At this time, the backfilling material 4 is in a state of entering under the tubular body 2 from one side at the angle of repose α of its own.

Next, as shown in FIG. 4, the carrier pipe 12 is sunk in the side portion on the opposite side of the pipe body 2, the weight 13 is grounded, and the injection nozzle 8 is directed toward the gap a below the pipe body 2, and the sand pump 11 is provided.
Is actuated to suck the backfill material 4 together with water, send it as a slurry to the bottom of the water, and jet it toward the bottom of the pipe 2 from the jet nozzle 8 to settle the remaining gap a by allowing the backfill material 4 to settle. fill in.

In this way, after the filling of 5 to 6 m in the longitudinal direction of the pipe body at one position, the position of the injection nozzle 8 is further retracted to the longitudinal direction of the pipe body 5 to 6 m, and the next filling is performed. To do.

At this time, the angle of the injection nozzle 8 is 45 with respect to the axial direction of the tube body 2 in the horizontal direction as shown in FIGS ^. The vertical direction is preferably horizontal or slightly upward, and the angle and the jet flow velocity are most effective for the backfill material to settle below the pipe depending on the particle size and specific gravity of the backfill material used. Others will be selected by a test at the beginning of filling so that they will be continuously processed.

As the backfill material 4, various powdered and granular materials such as grain crushed stone, single grain crushed stone, coarse sand, granulated slag, granular slag, and coal ash granulated material can be used.

In this way, the bottom of the tube 2 is completely filled,
After that, the backfill material 4 is put in using a normal bucket or other normal dropping device, the inside of the concave groove 1 is filled, and the pipe body 2 is buried.

In the above example, the filling is performed by injecting the slurry after closing it by dropping the backfill material on one side of the gap below the tubular body 2, but the slurry is injected as shown in FIG. 7 (c). The gap filling operation may be performed only by injecting

Experimental Example Next, an experiment using a model according to one embodiment of the present invention will be described.

1. Experimental Model The experimental model was performed on a 1/2 scale as shown in Table 1. Along the scale of the length scale, a similarity rule is applied between the actual phenomenon and the measured value of the experiment. Froude's law is applied to the similarity rule. Therefore, not only the experimental apparatus but also the crushed stone having a particle size of 1/2 of the particle size used in the field was used.

2. Experimental equipment As shown in FIG. 6, a model steel pipe 21 of a buried pipe body having a diameter of 2000 mm is installed in the water tank 20 at a distance of 250 mm from the water bottom, and the injection nozzle 22 is oriented in the horizontal direction, and
Installed at an angle of 45 degrees to the axial direction of the model steel pipe 21,
The trolley 23 on the water tank 20 was supported, and the slurry was conveyed and jetted by the sand pump 24.

In the figure, 25 is a velocity meter, 26 is a throttle valve,
27 is a submersible pump for water supply.

3. Backfill material used The material used is for crushed grain (10-40 mm), coarse sand, granulated slag No. 7 (2.5-5 mm), etc. for filling properties, expected ground reaction coefficient, and coating. The No. 7 crushed stone was selected based on the evaluation and judgment based on the impact.

Since the model scale was halved during the experiment, the material used had a similar particle size distribution, and the 50% particle size was ½ that of No. 7 crushed stone. In addition, a material equivalent to sea sand was prepared for comparison with the conventional method.

4. Results of gap filling experiment under tube (1) Case 1 a. Method: After closing one of the gaps under the tubular body with a pile in which the backfill material is piled up by direct casting on one side of the steel pipe 21,
Filling was performed by slurry injection. At this time, the angle of repose of the mountain was 30 degrees. b. Material used and slurry concentration: No. 7 crushed stone equivalent (Meisei Sand), 8% c. Flow rate and injection time: 2 (m / sec), 10 minutes d. Measurement / measurement items: filling status, filling shape, flow rate, time, water carrying amount e. Result: As shown in Fig. 7 (a), the area immediately below the pipe was filled with the material, and the area was closed, and a gap was partially formed in the skirt that was previously charged. (2) Case 2 a. Method: After closing one of the gaps under the tubular body with a pile in which the backfill material is piled up by direct casting on one side of the steel pipe 21,
Filling was performed by slurry injection. At this time, the angle of repose of the mountain was 30 degrees. b. Materials used and slurry concentration: No. 7 crushed stone equivalent product (Meisei Sand), 9.3% c. Flow rate and injection time: 2.5 (m / sec), 10 minutes d. Measurement / measurement items: filling status, filling shape, flow rate, time, water carrying amount e. Result: As shown in FIG. 7 (b), all of the gaps just below the pipe and the ridge gaps that were previously charged were filled. (3) Case 3 a. Method: Filling was performed by slurry injection in a state where both sides of the gap below the tubular body were open. b. Material used and slurry concentration: No. 7 crushed stone equivalent (Meisei Sand), 9.6% c. Flow rate and injection time: 2.5 (m / sec), 14 minutes d. Measurement / measurement items: filling status, filling shape, flow rate, time, water carrying amount e. Result: As shown in FIG. 7 (c), since the amount of soil to be sent was large, filling immediately under the pipe was fast and some voids remained on the opposite side of the discharge port. (4) Case 4 a. Method: Similar to the conventional method, backfilling was performed only by dropping. b. Material used: No. 7 crushed stone equivalent product (Meisei Sand) c. Measurement / measurement items: filling status, filling shape d. Result: As shown in FIG. 8, the ridges on both sides entered under the steel pipe with their angles of repose, but a gap remained just below the pipe. (5) Case 5 a. Method: Similar to the conventional method, backfilling was performed only by dropping. b. Materials used: Sea sand equivalent (grain preparation) c. Measurement / measurement items: filling status, filling shape d. Result: As shown in FIG. 8, the ridges on both sides entered under the steel pipe with their angles of repose, but a gap remained just below the pipe.

[0029]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, the backfill material such as crushed stone is filled with water, conveyed as a slurry, and jetted toward the gap below the laid pipe body by the injection nozzle to fill the underbody of the pipe body. By doing so, even if there is a small gap under the laid pipe body, it will be densely filled, so that the groove formed on the bottom of the water can be made shallower than before, and the weight of the pipe body Since it can be supported by the backfill material, it is possible to use a tube body having a smaller wall thickness than the conventional one, and it is possible to greatly reduce the cost.

In addition, at the time of filling, a backfill material is put into the concave groove on one side of the water bottom laying pipe installed in the pipe laying groove so that one side of the gap below the laying pipe is filled. Closed,
After that, by injecting the slurry from the other side portion into the gap below the water bottom laying pipe to fill the backfill material under the water bottom laying pipe, a complete filling operation can be efficiently performed.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an outline of an apparatus used in a method of the present invention.

FIG. 2 is a cross-sectional view showing a state before carrying in a backfill material in a construction step of the method of the present invention.

FIG. 3 is a cross-sectional view showing a closed state on one side of the gap when the backfill material is charged.

FIG. 4 is a cross-sectional view showing a filling state by the above-mentioned slurry injection.

FIG. 5 is a plan view of the same.

FIG. 6 is a sectional view showing experimental equipment of the present invention.

7 (a) to 7 (c) are cross-sectional views showing experimental results by the method of the present invention.

FIG. 8 is a sectional view showing an experimental result by a conventional method.

[Explanation of symbols]

a gap 1 Pipe laying groove 2 Water bottom laying pipe 3 Support materials 4 Backfill material 5 storage tanks 6 earth transport 7 Transport means 8 Slurry injection nozzle 10 Submersible pump 11 Sand pump 12 carrier tubes 13 weights 20 aquarium 21 model steel pipe 22 injection nozzle 23 dolly 24 Sand pump 25 Anemometer 26 Squeeze valve 27 Submersible Pump

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigehiro Ozaki Marunouchi 2-5 No. 5 in Takamatsu City, Kagawa Prefecture Shikoku Electric Power Co., Inc. (72) Shinobu Yamazaki 1007, Murei Town, Mure Town, Kida-gun, Kagawa Prefecture 3 Stock Company 4 Electrical engineering consultant (72) Inventor Yoshitaka Otani 4-4-3 Chifune-cho, Matsuyama-shi, Ehime Prefecture Syogoku Branch Co., Ltd. (72) Inventor Sadao Tashita 4-4-3 Chifune-cho, Matsuyama-shi, Ehime Prefecture Goyo Construction Co., Ltd. Shikoku Branch (72) Inventor Shigeru Inoue 4-4-3 Chifunecho, Matsuyama City, Ehime Prefecture Goyo Construction Co., Ltd. Shikoku Branch (56) Reference JP-A-57-178018 (JP, A) Japanese Patent Laid-Open No. 7-127042 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16L 1/12 E02B 3/00 E02D 17/12

Claims (4)

(57) [Claims] 1. A pipe bottom of a water bottom laying pipe body in which a backfill material is filled in a gap below the water bottom laying pipe body provided at a distance from the bottom face of the groove in a groove for pipe laying formed by excavation on the water bottom. In the filling method, a backfill material such as crushed stone and / or sand is mixed with water on land or on a ship to form a slurry, and the slurry is sent to a side portion of the water bottom laying pipe through a transfer pipe, A method for filling a bottom of a water bottom laying pipe by filling the backfill material under the bottom of the water bottom laying pipe by injecting the slurry toward the bottom of the water bottom laying pipe. 2. A backfill material is introduced into the groove on one side of the water bottom laying pipe installed in the pipe laying groove to close one side of the gap below the laying pipe. Then, the backfill material is filled under the water bottom laying pipe body by injecting the slurry into the gap below the water bottom laying pipe body from the other side to fill the water bottom laying pipe body under the pipe. 3. The underfill filling method for a water bottom laying pipe according to claim 1, wherein the backfill material is crushed single-grain stone or sand. 4. A storage tank for accommodating a backfill material such as crushed stone and / or sand and pouring water into the storage tank to form a slurry, and means for transferring the slurry in the storage tank to a water bottom through a transfer pipe.
A pipe of a water bottom laying pipe body, which is connected to the front end portion of the conveying pipe of the conveying means, is installed on the water bottom by a weight, and has a slurry injection nozzle for injecting the slurry sent through the conveying pipe at a predetermined angle. Bottom filling device.