JP2021123983A - Tremie pipe and method for constructing structure - Google Patents

Abstract

To provide a tremie pipe which suppresses pollution by a charge material and allows the material to efficiently flow therethrough, and a method for constructing a structure using the tremie pipe.SOLUTION: A tremie pipe (1A) is provided with a pipe (10) for allowing a charge material to flow therethrough, and a slit-like opening (16) having a length of at least 20% with respect to a pipe length (LALL) of the pipe (10).SELECTED DRAWING: Figure 1

Description

The present invention relates to a method of constructing a tremie pipe and a structure.

Tremy pipes may be used to fill the sea with earth and sand in the backfilling of deep moat traces on the seabed, reclamation at harbors, submarine embankment, and shallow-field construction. The tremie pipe is placed in the sea with the upper end facing the seabed while the upper end is above the water surface, and earth and sand are poured from the upper end. By using the tremie pipe in this way, it is possible to suppress the generation of pollution in the sea and consider the environment.

As such a tremie pipe, there is a tremie pipe composed of a double pipe in which an outer pipe having a pipe diameter and a pipe length larger than that of the inner pipe is arranged around an inner pipe having an opening near the hydrostatic surface (Patent Documents 1 to 1). 3). The opening provided in the inner pipe is provided for the purpose of venting air from the inner pipe to the outer pipe and for the purpose of suppressing pollution diffusion at the time of sediment injection by water circulation between the outer pipe and the inner pipe.

By the way, as a method of inputting the modified Calcia soil into the sea area, there are direct input (bottom open purge), grab input, and tremie type pump placement. Here, too, the tremie type pump driving method is listed as a method capable of suppressing the generation of pollution, but equipment for pump pumping is required for driving.

Japanese Unexamined Patent Publication No. 2002-129568 JP-A-2002-129569 Japanese Unexamined Patent Publication No. 2011-69076

When viscous materials such as calcia modified soil and dredged soil are thrown (cast) into the sea by a tremie pipe, there is a concern that the material may be separated or the tremie pipe may be blocked during the process of flowing down the tremie pipe. In order to prevent blockage of the tremie pipe, it is necessary to increase the pipe diameter, but if the pipe diameter is increased, the amount of seawater in contact with the input material increases, which causes pollution. Further, especially in the case of calcia modified soil, problems such as material separation and decrease in expression strength after casting occur due to material separation and entrainment of seawater.

Therefore, one aspect of the present invention is to provide a tremie pipe in which the material is efficiently flowed down by suppressing the generation of pollution due to the input material, and a method for constructing a structure using the tremie pipe.

In order to solve the above-mentioned problems, the tremie pipe according to one aspect of the present invention is a tremie pipe in which a material flows down inside the pipe, and has a slit-shaped opening extending along the pipe axis direction. , At least two different positions are provided along the circumferential direction of the pipe, and one slit length of the slit-shaped opening is equal to or larger than the pipe diameter of the pipe.

According to the above configuration, it is possible to provide a tremie pipe in which the material flows down efficiently by suppressing the generation of pollution due to the input material flowing down the inside of the pipe. Specifically, since the area of the inner surface of the tremie pipe is smaller by the opening area of the slit-shaped opening as compared with the pipe not provided with the slit-shaped opening, the input material and the inner surface of the tremie pipe are smaller. The contact area with is small. As a result, friction due to contact with the inner surface of the tremie tube can be reduced, and blockage can be suppressed. Further, according to the above configuration, even when the input material is a lump having a diameter substantially equal to the pipe diameter of the tremie pipe, if one slit length of the slit-shaped opening is equal to or larger than the pipe diameter. , Water can be circulated and air can be discharged at the upper and lower parts of the mass so that the pipe can flow down without being blocked. Further, since the blockage is unlikely to occur according to the above configuration, the material can flow down satisfactorily even if the diameter of the tremie pipe is smaller than the diameter of the pipe normally used. That is, it is possible to process the same input amount (per unit time) as before using a tremie tube thinner than before.

In order to solve the above-mentioned problems, the tremie tube according to another aspect of the present invention is a tremie tube in which a material flows down inside the tube, and is a slit-shaped opening extending along the tube axis direction. However, at least two different positions are provided along the circumferential direction of the pipe, and the total slit length, which is the sum of the slit lengths of the slit-shaped openings, is at least 20% of the pipe length of the pipe. have.

According to the above configuration, it is possible to provide a tremie pipe in which the material flows down efficiently by suppressing the generation of pollution due to the input material flowing down the inside of the pipe. Specifically, since the area of the inner surface of the tremie pipe is smaller by the opening area of the opening than the pipe without the opening, the contact area between the input material and the inner surface of the tremie pipe is small. .. As a result, friction due to contact with the inner surface of the tremie tube can be reduced, and blockage can be suppressed. Further, the total slit length of the slit-shaped opening is provided with a relatively long slit length of at least 20% of the pipe length of the pipe. Therefore, in the process of installing the tremie pipe in water and letting the input material flow down, water circulation occurs through the openings at positions above and below the position of the input material, making it difficult for the input material to block the pipe. Efficiently flow down. Further, even when the input material entrains air and is charged into the tremie pipe, the air can be discharged to the outside of the tremie pipe through the slit-shaped opening having the total slit length configured as described above. Further, according to the above configuration, since clogging is unlikely to occur, the material can flow down satisfactorily even if the diameter of the tremie pipe is smaller than the diameter of the pipe normally used. That is, it is possible to process the same input amount (per unit time) as before using a tremie tube thinner than before.

Further, in the tremie tube according to the other aspect of the present invention, the tremie tube may have a slit length of one slit of the slit-shaped opening equal to or larger than the tube diameter of the tube.

According to the above configuration, even when the input material is a lump having a diameter substantially equal to the pipe diameter of the tremie pipe, if one slit length of the slit-shaped opening is equal to or larger than the pipe diameter, the said material is concerned. Water can be circulated and air can be discharged at the top and bottom of the mass, allowing it to flow down without blocking the pipe.

Further, the tremie pipe has an inclined surface inside the pipe that is inclined toward the upstream side and the outward direction of the flow direction at the end of the slit-shaped opening on the downstream side in the flow direction of the material. You may be.

According to the above configuration, since there is no corner facing the inside of the pipe at the lower part of the slit-shaped opening, there is no possibility that the material flowing down the pipe is separated by the corner, and the occurrence of pollution accompanying this is suppressed. Can be done.

Further, the tremie pipe is provided with a hopper provided with a through hole communicating with the inside of the pipe on the upper end side of the pipe, and the through hole is a corner portion or a peripheral portion of the hopper in a plan view. In the hopper, the flow path leading to the through hole starts from a position symmetrical to the through hole in a plan view and is inclined downward toward the through hole, and the through hole is provided. The flow path leading to the above may have a V-shaped valley, a trapezoidal shape, or a U-shaped valley in cross-sectional view.

According to the above configuration, when the material is fed to the slope of the hopper, it accumulates on the slope and becomes agglomerates. That is, the mass (m) of the mass gradually increases on the inclined surface. Here, the force acting in the slope direction of an object on an inclined surface is generally expressed as mg × sin θ (mg is the gravity of an object having a mass m, θ is the inclination angle of the inclined surface with respect to the horizontal plane), and according to the above configuration. The force acting in the direction of the slope of the mass that accumulates on the slope and grows gradually increases. Then, when the force exceeds the static friction force, the mass slides out, reaches the through hole, and flows into the tremie pipe. That is, with the above configuration, since the dropped material is dropped into the pipe as a lump of a desired size, the dropped material is unlikely to be dispersed and pollution is unlikely to occur.

Further, the tremie pipe is arranged on the lower end side of the pipe and has a cylindrical shape extending downward along the pipe axis direction from the lower end side of the pipe or a shape extending in the pipe radial direction as the pipe extends downward to prevent pollution. A film may be further provided, and a weight may be attached to the anti-pollution film on the side opposite to the lower end of the tube.

According to the above configuration, since the anticontamination film is provided, the contamination range can be limited even if the material dropped from the lower end of the tremie pipe causes contamination. Further, for this reason, the lower end of the tremie pipe can be arranged at a position away from the seabed or the dropped material layer previously dropped and deposited. In addition, the length of the tremie tube can be shortened by the amount of the anticontamination film.

Further, since the weight is attached to the anticontamination film, the anticontamination film can be reliably installed.

Further, the tremie tube may have a tube diameter of 300 mm or more and 2000 mm or less.

According to the above configuration, even a tremie pipe having a relatively small diameter of 300 mm or more and 2000 mm or less can suppress the generation of pollution and allow the dropped material to flow down efficiently.

Further, the tremie pipe may be a double pipe in which an outer pipe is arranged on the outer peripheral side of the pipe.

According to the above configuration, even when pollution flows out of the pipe (inner pipe) through an opening having a relatively long slit length in the pipe (inner pipe), the outer pipe is provided. It is possible to prevent the spread of pollution outside the tremie tube.

Further, in the tremie pipe, the hopper has a second region of the flow path in which the first region adjacent to the through hole is located farther from the first region than the first region. The inclination angle with respect to the horizontal plane may be smaller than that.

According to the above configuration, since the first region has a gentler inclination angle than the second region, the viscous material tends to accumulate in the first region and form a lump. By charging the lumpy viscous material from the upper end of the pipe, the viscous material becomes lumpy, and it is possible to suppress the dispersion of the viscous material in the sea while falling in the pipe.

Further, in the tremie pipe, the hopper may be connected to the upper end of the pipe via a joint pipe having displacement absorption.

According to the above configuration, the joint pipe having the displacement absorbing property allows the pipe to rotate about the hopper.

Further, in order to solve the above-mentioned problems, the structure construction method according to one aspect of the present invention is a structure construction method for constructing a structure in which a viscous material is deposited, and is the tremie pipe. The installation process of installing the pipe in water, the charging step of charging the viscous material into the tremie pipe installed in the installation process, and the loading of the viscous material charged by the charging step into water from the pipe. It includes a construction step of constructing the structure by driving the structure at a predetermined position.

According to the above configuration, it is possible to provide a tremie pipe in which the material flows down efficiently by suppressing the generation of pollution due to the input material flowing down the inside of the pipe. Specifically, since the area of the inner surface of the tremie pipe is smaller by the opening area of the slit-shaped opening as compared with the pipe not provided with the slit-shaped opening, the input material and the inner surface of the tremie pipe are smaller. The contact area with is small. As a result, friction due to contact with the inner surface of the tremie tube can be reduced, and blockage can be suppressed. In the process of installing the tremie pipe in water and letting the input material flow down, water circulation occurs through the openings at positions above and below the position of the input material, making it difficult for the input material to block the pipe, which is efficient. Let it flow down to. Further, according to the above configuration, since clogging is unlikely to occur, the material can flow down satisfactorily even if the diameter of the tremie pipe is small. In other words, it is possible to process the same input amount (per unit time) as before using a thinner tremie pipe than before, which reduces costs and improves workability such as installation, and is affected by tidal currents in the sea. Is also reduced. Further, even when the viscous material entrains air and is charged into the pipe, the air is removed from the slit-shaped opening to the outside of the tremie pipe to promote the fall of the charged material inside the tremie pipe. Can be done.

Therefore, according to the above configuration, it is possible to efficiently construct the structure while suppressing the generation of pollution.

Further, in the construction method, the viscous material may be selected from the group consisting of dredged soil, PS ash-based modified soil, calcia-based modified soil, lime-based modified soil and cement-modified soil.

According to the above configuration, even a viscous material as illustrated can be satisfactorily dropped by suppressing material separation and tube blockage.

According to one aspect of the present invention, it is possible to provide a tremie pipe in which pollution caused by an input material (viscous material) is suppressed and the material flows down efficiently, and a method for constructing a structure using the tremie pipe. ..

It is a front view of the Tremy tube which concerns on one Embodiment of this invention. It is a cross-sectional view of the tremie pipe shown in FIG. 1 and the figure which shows typically the state of putting earth and sand into the tremie pipe and falling. It is a top view of the hopper of the tremie tube shown in FIG. It is sectional drawing of the hopper of the tremie tube shown in FIG. It is a front view of the tremie tube which concerns on other embodiment of this invention. It is an enlarged cross-sectional view of the part where the slit of the Tremy tube which concerns on another Embodiment of this invention is provided. It is a cross-sectional view taken along the arrow which shows the state of the cross section which cut the tremie tube at the cutting line AA'shown in FIG. It is a front view of the tremie tube which concerns on other embodiment of this invention. It is a partial cross-sectional view of the Tremy tube shown in FIG. It is a partial front view of the tremie tube which concerns on other embodiment of this invention.

[Embodiment 1]
Hereinafter, the tremie tube according to the embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is a front view of the tremie pipe according to the first embodiment. The tremie pipe 1A according to the first embodiment is used when pouring earth and sand into water, and is used in construction work for constructing a structure from the earth and sand. In particular, it is used for backfilling the remains of deep moats on the seabed, reclamation at harbors, and construction of shallow areas.

As will be described later, the tremie pipe 1A allows a viscous material such as Calcia modified soil to flow down efficiently while suppressing the generation of pollution. Therefore, the tremie tube 1A includes a tube 10 and a hopper 20.

The pipe 10 is provided with slit-shaped openings 16 extending along the pipe axis direction of the pipe 10 at at least two different positions along the circumferential direction of the pipe 10. Each of these openings 16 has a slit length longer than the pipe diameter of the pipe 10. This will be described in detail below.

The pipe 10 is, for example, a pipe body installed in the vertical direction in the sea, and when both ends are formed by one end 12 (upper end) and the other end 14 (lower end) and installed in the vertical direction, the pipe 10 is installed. One end 12 is located above the sea and the other end 14 faces the seabed.

The slit-shaped opening 16 provided in the pipe 10 is an opening provided through the pipe wall of the pipe 10, and seawater can freely flow inside and outside the pipe 10 in the slit-shaped opening 16. It is movable. Further, the air inside the pipe 10 can be discharged to the outside of the pipe 10 through the slit-shaped opening 16.

The slit-shaped opening 16 is an elongated slit extending from one end 12 side of the pipe 10 toward the other end 14. Since the slit-shaped opening 16 is provided, the area of the inner peripheral surface of the pipe 10 is as small as the opening region of the slit-shaped opening 16 as compared with the case where the slit-shaped opening 16 is not provided. .. In other words, the area of the tube 10 in contact with the viscous material is smaller as the opening area is concerned. As a result, the frictional resistance of the viscous material can be reduced and blockage can be prevented.

Eight slit-shaped openings 16 are provided along the circumferential direction of the pipe 10. Specifically, the eight slit-shaped openings 16 are provided at intervals of about 45 ° along the circumferential direction centered on the pipe axis. The slit-shaped openings 16 may be provided at a plurality of different positions along the circumferential direction of the pipe 10, and are not limited to eight. For example, it may be appropriately set according to the slit width W _S such slit-shaped opening 16 which tube diameter, and later to the tube 10. The plurality of slit-shaped openings 16 may or may not be evenly arranged along the circumferential direction. Further, the start positions of the plurality of slit-shaped openings 16 provided along the circumferential direction may be different start positions, and the widths of the slit-shaped openings may not be the same.

Regarding the size of the pipe 10, when the viscous material is put into the tremie pipe as a mass having the same size as the pipe diameter, the smaller the pipe diameter, the more the viscous material flowing down the pipe 10 with the seawater at the upper end and the lower end. The contact area can be reduced to suppress the occurrence of pollution. For example, the pipe diameter of the pipe 10 can be 300 mm or more and 2000 mm or less. The length of the pipe 10 is not particularly limited, but may be a relatively long pipe length of 10,000 mm or more. As an example, a pipe 10 having a pipe diameter of 800 mm and a length of 12000 mm is provided with eight slit-shaped openings 16 having a slit width of 10 mm and a slit length of 10000 mm evenly in the circumferential direction.

The hopper 20 is connected to one end 12 (upper end) of the pipe 10 and has a large opening toward the zenith in order to facilitate the injection of the viscous material into the inside of the pipe 10, and one side of the pipe 10 at the lower end. It communicates with the end 12 of.

Here, the function of the tremie tube 1A of the present embodiment will be described with reference to FIG. FIG. 2 is a cross-sectional view of the tremie pipe 1A vertically divided along the pipe axis direction of the pipe 10. In FIG. 2, for convenience of explanation, only three slit-shaped openings 16 are shown.

FIG. 2 shows a state along the time series from the left edge to the right edge of the paper. The state shown at the left end shows that the viscous material carried by the belt conveyor 100 is falling into the hopper 20 from the opening provided at the zenith of the hopper 20. The hopper 20 is provided with a ramp 24, which will be described in detail later, and the viscous material dropped from the belt conveyor 100 falls near the central portion of the ramp 24. After that, the supplied material is stored and becomes a mass of soil 200 of a certain size, reaching one end 12 of the pipe 10. In this case, the clay mass of the viscous material is in a state of being fitted in the pipe 10. According to this, the contact area between the clay mass of the viscous material and the seawater can be limited to the upper surface and the lower surface of the soil mass of the viscous material. As a result, it is possible to suppress the dispersion of soil mass of the viscous material and suppress the occurrence of pollution in seawater. However, the soil mass of the viscous material is not limited to this, and the soil mass may have a length equal to or less than the pipe diameter. When the soil mass has a length equal to or less than the pipe diameter, the soil mass will rotate in the pipe 10 even if it is initially fitted in the pipe 10, and the entire mass will come into contact with seawater. The viscous material dropped from the belt conveyor 100 may be dropped near the upper part of the ramp 24.

The viscous material soil mass 200 fitted in the pipe 10 flows down in the pipe 10 due to its own weight, and the air accumulated under the viscous material soil mass at this time passes through the slit-shaped opening 16. It is discharged to the outside of the pipe 10. Further, while flowing down the pipe 10, seawater circulates at the upper and lower positions of the soil mass 200 as shown at the right end of the paper in FIG. That is, the seawater in the pipe 10 is discharged to the outside of the pipe 10 through the slit-shaped opening 16 on the downstream side of the soil mass 200. At the same time, seawater outside the pipe 10 flows into the pipe 10 on the upstream side of the soil mass 200 through the slit-shaped opening 16. Here, the viscous material is continuously or intermittently charged into the tremie tube 1A from the belt conveyor 100. Therefore, as shown at the right end of the paper, there is a possibility that a plurality of soil lumps 200 exist in the pipe 10. Even when there are a plurality of soil masses 200, for each soil mass 200, the seawater in the pipe 10 is discharged to the outside of the pipe 10 on the downstream side of the soil mass 200, and the pipe 10 is discharged into the pipe 10 on the upstream side of the soil mass 200. Outside seawater flows in. As described above, in the case of a soil mass slightly smaller than the pipe diameter, if the pipe does not have the slit-shaped opening 16, pulsation occurs, and the input material is dispersed in this process. However, in the case of the pipe 10 of the present embodiment, the pulsation is suppressed and the dispersion of the material is suppressed by the inflow and drainage of water from the slit-shaped opening 16.

In this embodiment, the opening size of the slit-shaped opening 16 is defined as follows in order for each soil mass 200 to flow down smoothly.

_{(Slit length L S of the} slit-shaped opening 16)
Of each slit-shaped opening 16 slit length L _{S (1} slit length) is set to on the tube diameter or the tube 10. As a result, even when the viscous material is a soil mass 200 having a diameter substantially equal to the pipe diameter of the tremie pipe 1A, seawater is circulated and air is discharged at the upper and lower parts of the soil mass 200, and the pipe 10 is blocked. It can be made to flow down without.

Further, in the present embodiment, as shown in FIG. 1, it has a first slit length _{L S} and about 85% of the tube length (total _{length) L ALL} as an example. As a result, a relatively long slit-shaped opening is formed in the pipe 10, which contributes to a smoother flow of the soil mass 200. However, it is not limited to these numerical values. For example, each slit-shaped opening 16 slit length _L S (1 slit length), preferably has at least 20% of the length of the pipe length _{L ALL} of the tube 10. Alternatively, if the holding member for holding the circular tube shape of the tube 10 are separately provided, each slit-shaped opening 16, may have a slit length L _S equal to the pipe length (total length) L _ALL good.

(Slit width _W S of the slit opening 16)
Slit opening 16 length along the circumferential direction of the respective tube 10, so the slit width W _S, together with the circulating seawater when the soil mass 200 of viscous material flows down, contact with clod 200 of viscous material 20 mm or less is desirable from the viewpoint of suppressing the outflow of the input material to the outside of the pipe while reducing the area. The slit width _{W S} can be 10mm for example. However, the value is not limited to these values, and may be set according to the properties of the target viscous material. Incidentally, if the opening 16 of about 10mm slit width W _S, can be relatively easily formed by grinding the tube wall of the tube 10 in the tube axis direction by a grinder.

(Hopper 20)
The hopper 20 will be described with reference to FIG. FIG. 3 is a plan view of the hopper 20. The hopper 20 is provided with a through hole 22 that communicates with one end 12 of the pipe 10. The through hole 22 is provided at a corner of the hopper 20 in a plan view. Further, in the hopper 20, the flow path leading to the through hole 22 starts from a position symmetrical to the through hole 22 in a plan view and is inclined downward toward the through hole 22. Specifically, the hopper 20 has a valley shape (V-shaped valley, trapezoidal shape, or U-shaped valley), and is a first inclined surface on one side of the inclined road 24 corresponding to the valley bottom. It has a 26a and a second inclined surface 26b on the other side, and a through hole 22 is located at one end of the inclined path 24. Therefore, the flow path leading to the through hole 22 is configured to start from the vicinity of the zenith-side end of the first inclined surface 26a and the second inclined surface 26b toward the valley. One end 12 of the pipe 10 is arranged directly below the through hole 22. By configuring the hopper 20 in this way, the viscous material dropped from the belt conveyor 100 has a desired size while flowing through the flow path from the position dropped on the hopper 20 to the through hole 22. It becomes a lump of soil. Actually, the angle of the inclined plate and the shape of the hopper are changed or adjusted as shown in FIG. 4 so as to form a mass having a desired size. As a result, the soil mass of a desired size is dropped into the pipe 10, so that the viscous material that has become the soil mass is less likely to be dispersed in the pipe 10 and is less likely to cause pollution. Here, in the hopper 20, the ramp 24 is also inclined with respect to the horizontal plane, and there is a through hole 22 below the ramp. The inclination angle of the ramp 24 with respect to the horizontal plane may be smaller or larger than the tilt angle of the first slope surface 26a and the second slope surface 26b with respect to the horizontal plane. When the inclination angle of the ramp 24 with respect to the horizontal plane is smaller, the viscous material that has flowed down the first slope 26a or the second slope 26b to the ramp 24 is stored in the ramp 24 and reaches the through hole 22. It flows. Therefore, there is an advantage that the viscous material tends to be a mass of soil having an appropriate size.

A cross-sectional view of the ramp 24 is also shown on the lower side of the paper in FIG. This cross-sectional view is a cross-sectional view taken along the line AA'added to the hopper 20 on the upper side of the paper surface of FIG. The ramp 24 corresponding to the valley bottom may have a V shape in which the first slope 26a and the second slope 26b intersect in a cross-sectional view ((i) in FIG. 3). )). Alternatively, the intersecting portions may have a curved U-shape ((ii) in FIG. 3). In the present specification, the ramp 24 having a V shape is referred to as a V-shaped valley, and the ramp 24 having a U-shape with curved intersecting portions is referred to as a U-shaped valley. It is called. Further, the ramp 24 corresponding to the valley bottom has a shape in which the first inclined surface 26a and the second inclined surface 26b are flat, that is, the valley bottom is flat in cross-sectional view, instead of these shapes. It may be present ((iii) in FIG. 3). In the present specification, the ramp 24 having a flat valley bottom is referred to as a trapezoidal shape.

It should be noted that it may not have the shape of a valley like the ramp 24, but may simply have a through hole 22 at a corner portion, with the through hole 22 facing downward, and having only an inclined surface. In this case, the viscous material may be dropped from the belt conveyor 100 on the central portion or the upper portion of the inclined surface.

FIG. 4 shows a modified example of the hopper 20. Hereinafter, a modified example will be described.

(Hopper 20A)
The hopper 20A shown in FIG. 4 is different from the above-mentioned hopper 20 in the arrangement position of the through hole 22. The hopper 20A has a through hole 22 arranged in a peripheral portion of the hopper 20A. Along with this, the ramp 24 also extends toward the through hole 22 in the peripheral portion. Also in this hopper 20A, one end 12 of the pipe 10 is arranged directly below the through hole 22. Even in the hopper 20A of this modified example, the flow path leading to the through hole 22 starts from the zenith end (upper part) of the first inclined surface 26a and the second inclined surface 26b toward the valley. It is composed.

(Hopper 20B)
In another hopper 20B shown in FIG. 4, the through hole 22 is arranged at a corner of the hopper. In the hopper 20B, the first boundary portion 25a and the second boundary portion 25b are provided, and the through hole 22 is located on the lower side of the inclination between the first boundary portion 25a and the second boundary portion 25b. A third inclined surface 26c is provided. The third inclined surface 26c corresponds to the inclined path 24 (FIGS. 2 and 3) of the hopper 20 shown in FIG. A first inclined surface 26a is provided on the opposite side of the third inclined surface 26c and the first boundary portion 25a, and a second inclined surface is provided on the opposite side of the second boundary portion 25b. 26b is provided. Even with this hopper 20B, the viscous material tends to flow down while accumulating on the third inclined surface 26c to form a lump of an appropriate size.

(Hopper 20C)
Another hopper 20C shown in FIG. 4 has a through hole 22 arranged in a peripheral portion of the hopper 20C as in the case of the hopper 20A described above. Further, the hopper 20C is provided with a first boundary portion 25a and a second boundary portion 25b like the hopper 20B, and is inclined downward between the first boundary portion 25a and the second boundary portion 25b. A third inclined surface 26c on which the through hole 22 is located is provided on the side. A first inclined surface 26a is provided on the opposite side of the third inclined surface 26c and the first boundary portion 25a, and a second inclined surface is provided on the opposite side of the second boundary portion 25b. 26b is provided. Here, too, the viscous material tends to flow down while accumulating on the third inclined surface 26c described above, forming a mass of an appropriate size.

(Hopper 20D)
Another hopper 20D shown in FIG. 4 is a modified form of the third inclined surface 26c in the hopper 20C described above. In explaining the difference from the hopper 20C described above, the cross-sectional view shown on the right side of the paper surface of the hopper 20D of FIG. 4 is used. This cross-sectional view is a cross-sectional view taken along the line BB'attached to the hopper 20D shown on the left side of the paper in FIG. The third inclined surface 26c'in the hopper 20D has a first region 261 adjacent to the through hole 22 and a second region 262 located farther from the through hole 22 than the first region 261. doing. The inclination angle θ1 of the first region 261 with respect to the horizontal plane is smaller than the inclination angle θ2 of the second region 262 with respect to the horizontal plane. As described above, since the first region 261 has a gentler inclination angle than the second region 262, the viscous material tends to accumulate in the first region 261 and form a lump. By charging the lumpy viscous material from one end 12 (upper end) of the pipe 10, the viscous material becomes lumpy, and the dispersion of the viscous material in the sea while falling in the pipe 10 is suppressed. Can be done. The inclination angle θ1 of the first region 261 having a gentle inclination angle can be, for example, 18 °, and the inclination angle θ1 of the second region 262 can be, for example, 45 °. However, the angle is not limited to these.

(Material of each component)
The tube 10 can be made of materials used for well-known tremie tubes. For example, a steel pipe or the like can be adopted. Among them, in the first embodiment, it is preferable to use a steel pipe so that the structural strength can be maintained even if the slit-shaped opening 16 is provided in a wide range.

The hopper 20 can be made of a material that constitutes a well-known hopper such as an iron plate.

(Viscous material and input form)
The viscous material to be flowed down by the tremie pipe 1A of the first embodiment may be selected from the group consisting of dredged soil, PS ash-based modified soil, calcia-based modified soil, lime-based modified soil and cement-modified soil. .. Since these viscous materials have a relatively high viscosity, they tend to form lumps and are difficult to disperse in the sea, but they tend to adhere to the inside of the tremie tube and block the tube. Therefore, in the tremie pipe 1A of the first embodiment, in order to suppress the contact area with the soil mass as much as possible, the inner peripheral surface of the pipe 10 is provided with a plurality of slit-shaped openings 16 and each having a constant length. The area is reduced to reduce the area of the surface that may come into contact with the soil mass.

However, the tremie pipe 1A can be used even for earth and sand other than the viscous material exemplified above. For example, it may be concrete.

Further, the viscous material is intermittently dropped into the pipe 10 in a mass of a certain size while flowing down the ramp 24 of the hopper 20. Therefore, as a method of charging the viscous material into the tremie pipe 1A, as described above, a mode in which a small amount of the viscous material is continuously conveyed by the belt conveyor 100 and continuously dropped into the hopper 20 can be adopted. .. Since the pipe diameter of the pipe 10 is relatively small as described above, it is preferable to adopt a mode in which a small amount can be continuously charged, such as a belt conveyor, rather than a mode in which a large amount of viscous material is charged at one time. In addition, even if the material is charged using a grab or backhoe bucket, it can be applied as long as it is a fluid material (for example, a flow value of 90 mm or more (NEXCO test method test method 313 air mortar and air milk test method). )).

When constructing a structure in which a viscous material is deposited using the tremie pipe 1A, first, the other end 14 of the pipe 10 is attached to the seabed, and the tremie pipe is submerged in the sea so that the pipe axis is along the vertical direction. 1A is erected. Then, the viscous material is dropped from the hopper 20 into the inside of the pipe 10 (loading step). The viscous material (soil mass) charged into the pipe 10 flows down the inside of the pipe 10 (FIG. 2). The other end 14 of the pipe 10 may be located away from the seabed, but considering that the viscous material (soil mass) flowing down to the other end 14 falls from the pipe 10, the other end 14 It is preferable that the distance between the end 14 and the seabed is close to each other. The viscous material that has landed on the seabed is deposited to construct a structure (construction process). In the process of depositing the viscous material on the seabed, the pipe 10 may be sequentially pulled up to the zenith so that the other end 14 is located near the surface of the deposit on the seabed. Further, instead of pulling up the pipe 10, the anticontamination film 40 may be sequentially pulled up to the zenith.

(Modification example of slit-shaped opening 16)
The slit-shaped opening 16 is not limited to the mode shown in FIG. 1, and may be a mode of each modification shown in FIG. Hereinafter, a modified example of the slit-shaped opening 16 will be described with reference to FIG.

The pipe 10A shown in FIG. 5 is provided with a slit-shaped opening 16 only in the region of one end 12 side half of the pipe 10A. The slit-shaped opening 16 is not provided in the region of the other end 14 side half of the tube 10A.

The pipe 10B, which is another modification shown in FIG. 5, has a slit-shaped opening over substantially the entire length of the pipe 10B, except for the end on one end 12 side and the end on the other end 14 side of the pipe 10B. The part 16 is provided.

The pipe 10C, which is another modification shown in FIG. 5, has a slit-shaped opening except for one end 12 side end portion and the other end 14 side end portion of the pipe 10C, and an intermediate portion 10 m of the pipe 10C. A portion 16 is provided. Specifically, the pipe 10C is provided with a slit-shaped opening 16 between the end on the one end 12 side and the intermediate portion 10 m, and the intermediate portion 10 m and the end on the other end 14 side are provided with each other. A slit-shaped opening 16 is provided between them. In the pipe 10C, a slit-shaped opening 16 on one end 12 side and a slit-shaped opening 16 on the other end 14 side are extended on the same line with the intermediate portion 10 m interposed therebetween. By providing an intermediate portion of 10 m having no slit-shaped opening, a structure capable of extending the steel pipe can be formed at this portion. Further, the structural strength of the pipe 10C can be increased as compared with a form in which the slit-shaped opening 16 is continuously provided over substantially the entire length of the pipe 10B, for example, as in the case of the pipe 10B described above.

The tube 10D, which is another modification shown in FIG. 5, is provided with a plurality of slit-shaped openings 16 in a houndstooth pattern. Slit length _{L S} of each slit-shaped opening 16 is about 20% of the tube length (total _{length) L ALL.} Each slit-shaped opening 16 has a relatively short slit length, but since a plurality of slit-shaped openings 16 are arranged in a houndstooth pattern over substantially the entire length of the pipe 10D, the same effect as that of the pipe 10B described above can be obtained.

The above is a modified example of the arrangement form of the slit-shaped opening 16 of the pipe 10. It should be noted that the present invention is not limited to these. However, in order to suppress the dispersion of the viscous material flowing down inside the pipe 10, the slit-shaped opening 16 extends along the pipe axis, and the pipe is viewed from the front as shown in FIGS. 1 and 5, for example. In this case, it is not desirable that the extension direction is inclined or orthogonal to the pipe axis. This is because the flowing direction of the viscous material intersects with the edge portion of the slit-shaped opening 16, so that the flowing viscous material may be dispersed by coming into contact with the edge portion.

Hereinafter, a preferred embodiment of the edge portion of the slit-shaped opening 16 will be described with reference to FIGS. 6 and 7.

(The edge of the slit-shaped opening 16)
FIG. 6 is a partial cross-sectional view of the pipe 10 and is a cross-sectional view at a position where the slit-shaped opening 16 is provided. As shown in FIG. 6, an inclined surface 16a inside the pipe, which is inclined toward the upstream and outward directions of the flow direction, is provided at the edge of the slit-shaped opening 16 on the downstream side in the flow direction of the viscous material. Has been done. The inclined surface 16a can be formed, for example, by adjusting the angle of the grinder when forming the slit-shaped opening 16 using the grinder.

FIG. 6 shows a state in which a clay mass of a viscous material is flowing down inside the pipe 10. Since the slit-shaped opening 16 is provided with the inclined surface 16a, the angle facing the inside of the tube 10 is obtuse. As a result, it is possible to suppress the dispersion of the clay mass of the viscous material when the soil mass of the viscous material comes into contact with the corner of the edge portion, as compared with the case where the angle is an acute angle.

FIG. 7 is a cross-sectional view taken along the line C—C ′ shown in FIG. 1 in which the pipe 10 is cut in the direction perpendicular to the pipe axis, but along the pipe axis in the slit-shaped opening 16. As for the upper edge portion, the corner of the edge portion may be substantially a right angle.

(Effect of Tremy Tube 1A of the first embodiment)
According to the first embodiment, the tremie pipe 1A is provided with a plurality of slit-shaped openings 16 extending along the pipe axis direction of the pipe 10 along the circumferential direction of the pipe 10, and each of them is provided. It has a slit length that is at least 20% of the length of the pipe 10. As a result, the inner peripheral surface of the pipe 10 is as small as the opening region of the slit-shaped opening, and the contact area of the viscous material with the soil mass can be reduced. It is possible to reduce the frictional resistance of the inner peripheral surface of the. Since the frictional resistance is small and seawater quickly flows into the upper part of the soil mass from the slit, a relatively large amount of viscous material can be smoothly flowed down even if the pipe diameter of the pipe 10 is small.

In other words, the same carry-out amount as the conventional tremie pipe can be carried out by the pipe 10 having a diameter smaller than that of the conventional tremie pipe. In construction work, the tremie pipe is long and heavy, so it is necessary to carry the tremie pipe itself when installing it on the seabed. When handling such a tremie tube, the tremie tube 1A of the first embodiment, which has a small diameter but allows a large amount of viscous material to flow down, has excellent convenience.

[Modification example]
In the above-described first embodiment, slit-shaped openings are provided at at least two different positions along the circumferential direction of the pipe, and one slit length of the slit-shaped opening 16 is equal to or larger than the pipe diameter of the pipe 10. .. As a result, the viscous material realizes that the tremie tube 1A can flow down smoothly without blocking the tube 1A. However, one embodiment of the present invention is not limited to this. For example, instead of setting one slit length of the slit-shaped opening 16 to be equal to or larger than the pipe diameter of the pipe 10, the slit-shaped openings 16 provided at at least two different positions along the circumferential direction of the pipe are provided. the total slit length which is the sum of length along the respective tube axis direction of the plurality of slit-shaped openings 16 in a manner that has at least 20% of the length of the pipe length (total length) L _ALL in the tube 10 There may be. That is, the total slit length is, have at least 20% of the length of the pipe length (total length) L _ALL in the tube 10, the slit length of each slit-shaped opening 16 (first slit length) of the tube 10 It may be smaller than the pipe diameter. Even in this embodiment, by defining the total slit length as described above, an opening (slit-shaped opening) is provided in a relatively long region along the pipe length in the pipe 10. Therefore, the circulation of water can be realized in the slit-shaped opening as described above, and the viscous material can smoothly flow down without blocking the tremie pipe 1A. The pipe length (total length) L _{ALL of the} pipe 10 corresponds to the length between one end 12 and the other end 14.

[Embodiment 2]
Other embodiments of the present invention will be described below with reference to FIGS. 8 and 9. For convenience of explanation, the same reference numerals will be added to the members having the same functions as the members described in the above embodiment, and the description will not be repeated.

FIG. 8 is a front view of the tremie tube 1B of the second embodiment. FIG. 8 corresponds to FIG. 1 of the first embodiment. FIG. 9 is a cross-sectional view of the tremie pipe 1B of the second embodiment cut along the pipe axis direction. FIG. 9 corresponds to FIG. 2 of the first embodiment.

The tremie pipe 1B is a double pipe having a single pipe structure of the tremie pipe 1A of the first embodiment, whereas the tremie pipe 1A has a pipe 10 as an inner pipe and an outer pipe 30 along the outer peripheral surface thereof. It differs in that it is structural. In FIG. 8, for convenience of explanation, the pipe 10 arranged inside the outer pipe 30 is shown by a broken line. Further, the tremie tube 1B is provided with a pollution prevention film 40 at the lower end of the outer tube 30, and a weight 50 is provided at the end of the pollution prevention film 40.

The outer pipe 30 prevents the diffusion of pollution derived from the viscous material that has come out of the pipe 10 through the slit-shaped opening 16 of the pipe 10 corresponding to the inner pipe and the other end 14. Therefore, the outer tube 30 has a length sufficient to cover at least the slit-shaped opening 16 of the tube 10. The outer peripheral surface of the pipe 10 and the inner peripheral surface of the outer pipe 30 are separated by a gap. As shown in FIG. 9, when a soil mass of a viscous material flows down the inside of the pipe 10, the seawater discharged to the outside of the pipe 10 through the slit-shaped opening 16 on the downstream side of the soil mass is said to be along the gap. It flows into the inside of the pipe 10 through the slit-shaped opening 16 on the upstream side of the soil mass. Since the circulating flow can be formed in this way, even if the seawater discharged from the pipe 10 is polluted due to a viscous material, the polluted seawater can be returned to the pipe 10 again. can.

At one end 12 of the tube 10, the end 32 of the outer tube 30 is separated from the one end 12. However, the present invention is not limited to this form, and a lid portion may be used in which one end 12 and the end 32 are sealed and a vent or the like is provided on the lid portion. In the second embodiment as well, the hopper 20 is connected to one end 12 of the pipe 10 as in the first embodiment.

A pollution prevention film 40 having a pipe structure is connected to the other end 34 of the outer pipe 30 so that the outer pipe 30 extends. The anticontamination film 40 is a conical tube whose diameter gradually increases as the distance from the other end 34 of the outer tube 30 increases. The anticontamination film 40 is not limited to a conical tube, and may be a cylindrical tube. The anticontamination film 40 can be made of a resin such as polyethylene or polypropylene.

Further, an annular weight 50 along the end of the anti-contamination film 40 is attached to the end of the anti-pollution film 40 opposite to the other end 34 of the outer pipe 30. The annular weight 50 can be made of a wire or the like.

When placing a structure made of a viscous material in the sea using the tremie pipe 1B, first, the weight 50 is brought close to the seabed, and the tremie pipe 1B is erected in the sea so that the pipe axis is along the vertical direction. Let (installation process). Then, the viscous material is dropped from the hopper 20 into the inside of the pipe 10 (loading step). The viscous material charged into the pipe 10 flows down the inside of the pipe 10. As shown in FIG. 9, the other end 14 of the pipe 10 is located away from the seabed, and the soil mass of the viscous material that has flowed down to the other end 14 falls from the pipe 10 and reaches the seabed (construction). Process). At this time, the anti-pollution film 40 prevents the diffusion of pollution generated from the soil mass of the viscous material in the process of falling, and also prevents the diffusion of sand and the like rolled up into the sea due to the impact of the soil mass landing on the seabed. can do.

The size of the outer pipe 30 may be such that it can cover at least the slit-shaped opening 16 of the pipe 10, and the pipe diameter is the pipe diameter of the pipe 10 corresponding to the inner pipe. It can be decided as appropriate in consideration. As an example, the following conditions can be met.
Tube 10: Tube diameter 800 mm, tube length 12000 mm (slit width 10 mm, slit length 10000 mm, 8 slit-shaped openings)
Outer pipe 30 ... Pipe diameter 1200 mm, pipe length 12000 mm
Contamination prevention film 40 ... Length 5000 mm
[Embodiment 3]
Other embodiments of the present invention will be described below with reference to FIG. For convenience of explanation, the same reference numerals will be added to the members having the same functions as the members described in the above embodiment, and the description will not be repeated.

FIG. 10 is a front view of the tremie tube 1C of the third embodiment. FIG. 10 corresponds to FIG. 1 of the first embodiment. The tremie pipe 1C is different from the tremie pipe 1A in that a flex pipe 60 (a joint pipe having displacement absorption) is provided between the hopper 20 and the pipe 10 of the tremie pipe 1A of the first embodiment.

In the flex tube 60, one tube end is connected to the hopper 20 and the other tube end is connected to the tube 10. The flex tube 60 can be displaced in the tube axis and can be expanded and contracted in the direction of the tube axis. Therefore, the tremie tube 1C has a configuration in which the tube 10 can rotate around the hopper 20.

When constructing a structure in which a viscous material is deposited using such a tremie pipe 1C, as in the case of the tremie pipe 1A of the first embodiment, initially, the pipe axis is vertically aligned and the tremie is submerged in the sea. The pipe 1C is erected and the viscous material is dropped (loading step). Then, in the tremie tube 1A of the first embodiment, the tube 10 is sequentially pulled up to the zenith in the process of depositing the viscous material on the seabed. As shown in FIG. 8, when the anti-contamination film 40 is attached to the pipe 10, the anti-contamination film 40 is pulled up to the zenith. After that, the tremie pipe 1C tilts the pipe 10 by moving the lower end 14 of the tremie pipe 1C as the viscous material is deposited on the seabed and the casting surface rises. Since the tremie tube 1C includes the flex tube 60, only the tube 10 can be tilted without tilting the hopper 20. As described above, according to the third embodiment, the tremie pipe can be easily moved as compared with the mode in which the pipe 10 of the first embodiment is simply pulled up.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

1A, 1B, 1C Tremy pipe 10, 10A, 10B, 10C, 10D pipe 10m Intermediate part 12 One end 14 The other end 16 Opening 16a Inclined surface 20, 20A, 20B, 20C, 20D Hopper 22 Through hole 24 Inclined path 25a First boundary portion 25b Second boundary portion 26a First inclined surface 26b Second inclined surface 26c, 26c ′ Third inclined surface 261 First region 262 Second region 30 Outer pipe 40 Contamination prevention film 50 Weight 60 Flex Tube 100 Belt Conveyor

Claims (12)

A tremie pipe in which the material flows down inside the pipe.
Slit-shaped openings extending along the pipe axis direction are provided at at least two different positions along the pipe circumferential direction.
A tremie tube characterized in that one slit length of the slit-shaped opening is equal to or larger than the tube diameter of the tube. A tremie pipe in which the material flows down inside the pipe.
Slit-shaped openings extending along the pipe axis direction are provided at at least two different positions along the pipe circumferential direction.
A tremie tube, wherein the total slit length, which is the sum of the slit lengths of the slit-shaped openings, has a length of at least 20% of the tube length of the tube. The tremie tube according to claim 2, wherein one slit length of the slit-shaped opening is equal to or larger than the tube diameter of the tube. The slit-shaped opening is characterized in that the edge portion of the material on the downstream side in the flow direction has an inclined surface inside the pipe that is inclined toward the upstream side and the outer direction in the flow direction. The tremie tube according to any one of claims 1 to 3. A hopper provided with a through hole communicating with the inside of the pipe is provided on the upper end side of the pipe.
The through hole is provided at a corner portion or a peripheral portion of the hopper in a plan view.
In the hopper, the flow path leading to the through hole starts from a position symmetrical to the through hole in a plan view, is inclined downward toward the through hole, and reaches the through hole. However, the tremie tube according to any one of claims 1 to 4, wherein the tremie tube has a V-shaped valley, a trapezoidal shape, or a U-shaped valley in a cross-sectional view. Further provided with an anti-pollution film which is arranged on the lower end side of the pipe and has a cylindrical shape extending downward along the pipe axis direction from the lower end side of the pipe or a shape extending in the pipe radial direction as the pipe extends downward.
The tremie tube according to any one of claims 1 to 5, wherein a weight is attached to the side of the anticontamination film opposite to the lower end of the tube. The tremie tube according to any one of claims 1 to 6, wherein the tube has a tube diameter of 300 mm or more and 2000 mm or less. The tremie tube according to any one of claims 1 to 7, wherein the outer tube is arranged on the outer peripheral side of the tube. In the hopper, the first region of the flow path adjacent to the through hole has an inclination angle with respect to the horizontal plane rather than the second region located farther from the through hole than the first region. The tremie tube according to claim 5, wherein is small. The tremie pipe according to claim 5, wherein the hopper is connected to the upper end of the pipe via a joint pipe having displacement absorption. It is a construction method of a structure that constructs a structure formed by depositing viscous materials.
The installation step of installing the tremie pipe according to any one of claims 1 to 10 in water, and
A charging step of charging the viscous material into the tremie pipe installed in the installation process, and a charging process.
A construction method comprising a construction step of dropping the viscous material charged in the charging step into water from the pipe and driving the viscous material into water at a predetermined location to construct the structure. The construction according to claim 11, wherein the viscous material is selected from the group consisting of calcia-modified soil, dredged soil, PS ash-based modified soil, lime-based modified soil, and cement-modified soil. Method.

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