Method for constructing tremie pipes and structures

Abstract

To provide a tremie tube that realizes rapid flow down of an input material and suppression of contamination generation.SOLUTION: A tremie tube (1A) according to one aspect of the present invention has, at an upper end (101), a plurality of inlets (17) arranged along the circumferential direction for discharging the air inside the tube when the material flows down inside the tremie tube so as not to hinder the flow of the material, and allowing water to flow from the outside of the tube to the upper part of the material after the material reaches the water in the tremie tube.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tremie pipe and a method for constructing a structure. [Background technology]

[0002] Tremie pipes are sometimes used to dump soil into the sea in construction works such as backfilling excavated areas in the seabed, reclamation in ports, construction of submerged embankments, and shallow area construction. The tremie pipe is placed in the sea with its upper end above the water surface and its lower end facing the seabed, and soil is dumped from the upper end. Using tremie pipes in this way helps prevent pollution in the sea and is environmentally friendly.

[0003] When viscous materials such as calcium oxide-improved soil and dredged soil are poured into the sea using a tremie pipe, there are concerns about material separation as the material flows down the pipe and clogging of the tremie pipe. In order to prevent clogging of the tremie pipe, it is necessary to increase the pipe diameter, but increasing the pipe diameter increases the amount of seawater that comes into contact with the poured material, which can cause pollution. In particular, in the case of calcium oxide-improved soil, problems such as a decrease in the strength developed after pouring can occur due to material separation and entrainment of seawater.

[0004] Furthermore, if the lump of material introduced into the tremie pipe is large and the pipe diameter is small compared to the lump, even if the material flows down the tremie pipe without clogging, pulsation will occur in the pipe where the water level repeatedly rises and falls, making it easy for material separation and turbidity to occur.

[0005] The tremie pipes disclosed in Patent Documents 1 to 3 are made of a double pipe in which an outer pipe, which is larger in both diameter and length than the inner pipe, is disposed around an inner pipe through which the material flows. The inner pipe has an opening for circulating water between the outer pipe and the inner pipe. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2002-129568 A [Patent Document 2] JP 2002-129569 A [Patent Document 3] JP 2011-69076 A Summary of the Invention [Problem to be solved by the invention]

[0007] There are several methods for feeding viscous materials such as calcia-improved soil and dredged soil into a tremie pipe. For example, a hopper is connected to the upper end of the tremie pipe and the material is fed into the pipe through the hopper. As a method for feeding materials into the hopper, a method using a belt conveyor that continuously feeds the material, as well as a method using a grab bucket or backhoe that feeds the material intermittently, are known. In particular, when a large grab bucket (several to 20 m3) or a backhoe bucket (several to 10 m3) is used to feed a large amount of calcia-improved soil or cement-solidified soil into a hopper for tremie casting, it is necessary to make the fed material flow down quickly. For example, even if the same amount is fed, feeding using a belt conveyor is a continuous supply, whereas feeding using a bucket does not feed the hopper in the process of grabbing and rotating the material, and materials such as soil and sand are fed in bulk at the stage of feeding into the hopper, so the material accumulates at the top of the tremie pipe from the hopper and is likely to clog the tremie pipe. Furthermore, if the material does not flow down quickly, the lumps of material will separate, increasing the surface area of ​​the lumps and raising concerns about increased turbidity.

[0008] Therefore, one aspect of the present invention aims to provide a tremie pipe that can achieve the rapid flow of charged materials, and a construction method for a structure using the tremie pipe. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, a tremie tube according to one embodiment of the present invention is a tremie tube through which material flows downward inside the tube, and when the tube is placed in water with one end of the tube in the air, the tremie tube has a plurality of inlets at a position straddling the water surface, and the plurality of inlets are arranged in a line along the circumferential direction of the tube.

[0010] According to the above-mentioned configuration, it is possible to provide a tremie pipe that realizes the rapid flow-down of the charged material. Specifically, since the inlet of the pipe is provided at a position straddling the water surface, immediately after the material is charged into the tremie pipe, the air below the lump of material and the air that entered the pipe with the material as the material flows down are rapidly discharged to the outside of the pipe, and after the material is submerged in water, water (e.g. seawater) can be flowed from the inlet to the top of the lump of material. This allows the material to flow down smoothly and does not clog the pipe.

[0011] Furthermore, in addition to the above-described configuration, a tremie tube according to one embodiment of the present invention may be configured such that, when the tube is placed underwater with one end of the tube in the air, the tube has a plurality of slits extending along the axial direction of the tube, some of which are in the air, and the plurality of slits are arranged along the circumferential direction of the tube.

[0012] According to the above-mentioned configuration, air that has entered the tube can be discharged to the outside of the tube through the area of ​​the slit that is exposed to the air.

[0013] Moreover, according to the above-mentioned configuration, it is possible to provide a tremie pipe that suppresses the generation of contamination caused by the input material flowing down inside the pipe in the area of ​​the slit located underwater, and allows the material to flow down efficiently. Specifically, since the area of ​​the inner surface of the tremie pipe is smaller by the opening area of ​​the slit, the contact area between the input material and the inner surface of the tremie pipe is small. This makes it possible to reduce friction caused by contact with the inner surface of the tremie pipe, and to suppress clogging. Furthermore, according to the above-mentioned configuration, since clogging is unlikely to occur, the material can be made to flow down smoothly even if the pipe diameter of the tremie pipe is smaller than that of a pipe normally used. In other words, it is possible to treat the same input amount (per unit time) as before using a tremie pipe that is smaller than before, which reduces costs and makes it easier to handle the installation, etc., improving workability, and reducing the influence of underwater tides. Furthermore, even if there is air that is caught in the material and cannot be released outside the pipe immediately after input, the air can be removed from the tremie pipe through the slit to promote the falling of the input material inside the tremie pipe.

[0014] In order to solve the above-mentioned problems, a tremie tube according to another aspect of the present invention is a tremie tube through which material flows downward inside, and when the tube is placed underwater with one end of the tube in the air, the tremie tube has a plurality of inlets located underwater, with upper ends of the plurality of inlets located at or just below the water surface, and the plurality of inlets are arranged in a line along the circumferential direction of the tube.

[0015] According to the above-mentioned configuration, it is possible to provide a tremie pipe that realizes the rapid flow-down of the charged material. Specifically, since the inlet provided in the pipe is located at or just below the water surface, immediately after the material is charged into the tremie pipe, the air below the lump of material and the air that entered the pipe with the material as the material flows down are rapidly discharged to the outside of the pipe, and after the material is submerged in water, water (e.g., seawater) can be flowed from the inlet to the top of the lump of material. This allows the material to flow down smoothly and does not clog the pipe.

[0016] In addition, in one or other aspects of the present invention, when the tremie tube is placed underwater with one end of the tube in the air, the tube may have a plurality of slits extending along the axial direction of the tube and positioned underwater, and the plurality of slits may be arranged along the circumferential direction of the tube.

[0017] According to the above-mentioned configuration, it is possible to provide a tremie pipe that suppresses the generation of contamination caused by the input material flowing down inside the pipe and allows the material to flow down efficiently. Specifically, since the area of ​​the inner surface of the tremie pipe is smaller by the opening area of ​​the slit, the contact area between the input material and the inner surface of the tremie pipe is small. This makes it possible to reduce friction caused by contact with the inner surface of the tremie pipe and suppress clogging. Furthermore, according to the above-mentioned configuration, since clogging is unlikely to occur, the material can be made to flow down smoothly 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 tremie pipe that is smaller than before, which reduces costs and improves workability such as installation, and reduces the influence of underwater tidal currents. Furthermore, even if there is air that is caught in the material and cannot be released outside the pipe immediately after input, the air can be removed from the tremie pipe through the slits to promote the falling of the input material inside the tremie pipe.

[0018] In addition to the above-described configuration, the tremie tube of one or other aspects of the present invention is preferably configured such that the total length of the opening widths of each of the inlets along the circumferential direction of the tube is greater than the total length of the slit widths of each of the slits.

[0019] According to the above-mentioned configuration, the inlet is opened relatively widely, so that soon after the material is charged into the tremie pipe, a large amount of water is supplied from the inlet to above the mass of material flowing down, thereby efficiently causing the mass of material to flow down to the lower end of the pipe.

[0020] In addition to the above-described configuration, in the tremie tube of one or another aspect of the present invention, each of the inlets may be located between one of the slits and another of the slits.

[0021] According to the above-mentioned configuration, since a wide open structure is realized in the area where the inlet of the pipe is provided, the material can be made to flow down quickly immediately after being dropped into the tremie pipe. Specifically, immediately after the material is dropped into the tremie pipe, a large amount of water is supplied from the part that opens above the mass of material flowing down (the inlet and the upper end part of the slit), so that the mass of material can be made to flow down efficiently to the lower end of the pipe.

[0022] Furthermore, in one or another embodiment of the tremie pipe of the present invention, a gap of a predetermined length is provided along the pipe axis direction between a first steel pipe and a second steel pipe, and the first steel pipe and the second steel pipe are connected by a plurality of connecting members lined up along the circumferential direction of the pipe, and the inlet may be formed by individual divided gaps formed by dividing the gap in the circumferential direction of the pipe by the plurality of connecting members.

[0023] According to the above-mentioned configuration, it is possible to provide a tremie tube that realizes a fast flow of material. Specifically, according to the above-mentioned configuration, the size of the inlet can be easily changed according to the target material, and therefore the size of the inlet can be changed for each material to be added, so that the material can flow smoothly and the tube is not clogged. In addition, the air inside the tube can be discharged to the outside of the tube from the inlet.

[0024] In addition to the above-mentioned configuration, the tremie pipe of one or another aspect of the present invention may have a pollution prevention pipe provided in the area below the water surface on the outer periphery of the pipe, forming a double pipe structure.

[0025] According to the above-described configuration, even if contamination flows out of the pipe (inner pipe), the outer pipe is provided, so that the contamination can be prevented from diffusing outside the tremie pipe.

[0026] In addition to the above-mentioned configuration, the tremie pipe of one or another aspect of the present invention may be provided with a pollution prevention frame or pollution prevention membrane in the area below the water surface on the outer periphery of the pipe.

[0027] According to the above-mentioned configuration, even if the contamination flows out of the pipe (inner pipe), the contamination can be prevented from diffusing because the contamination prevention frame or contamination prevention film is provided.

[0028] In addition, in order to solve the above-mentioned problems, a structure construction method according to one embodiment of the present invention is a method for constructing a structure formed by accumulating materials, and includes an installation step of installing the tremie pipe in water so that one end of the pipe is in the air, a feeding step of feeding material into the tremie pipe installed in the installation step, and a construction step of dropping the material fed in the feeding step from the pipe into the water and pouring it into a predetermined location, thereby constructing the structure.

[0029] According to the above configuration, a structure can be efficiently constructed using a tremie pipe that allows the input material to flow down quickly. Specifically, since water (e.g., seawater) can be made to flow into the pipe from the inlet, even if a large amount of material is dropped from the top of the tremie pipe, it can be made to flow down smoothly and the pipe will not be blocked. In addition, air inside the pipe can be discharged from the inlet. Furthermore, since construction can be performed using a tremie pipe with a smaller diameter than the pipe diameter normally used, installation and handling are easy, and construction efficiency is improved.

[0030] Therefore, according to the above-mentioned configuration, it is possible to efficiently construct a structure while suppressing the generation of pollution.

[0031] In the construction method, the material may be selected from the group consisting of calcia-modified soil, clayey soil, dredged soil, PS ash-based modified soil, lime-based modified soil, and cement-modified soil.

[0032] According to the above-mentioned configuration, even a viscous material such as the one exemplified above can be caused to flow quickly down after being dropped into the tremie tube, and material separation and blockage of the tube can be suppressed. Effect of the Invention

[0033] According to one aspect of the present invention, it is possible to provide a tremie pipe that enables the rapid flow of charged material, and a construction method for a structure using the tremie pipe. [Brief description of the drawings]

[0034] [Figure 1] FIG. 2 is a front view of a tremie tube according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a partial cross-sectional view of the tremie tube shown in FIG. [Diagram 3] FIG. 2 is a schematic diagram showing a state in which a material flows down the tremie pipe shown in FIG. 1. [Figure 4] FIG. 2 is a front view showing a modified example of the tremie tube shown in FIG. [Diagram 5] FIG. 11 is a front view of a tremie tube according to another embodiment of the present invention. [Figure 6] FIG. 11 is a front view of a tremie tube according to another embodiment of the present invention. [Figure 7] FIG. 11 is a front view of a tremie tube according to another embodiment of the present invention. [Figure 8] FIG. 11 is a front view of a tremie tube according to another embodiment of the present invention. [Figure 9] FIG. 11 is a front view of a tremie tube according to another embodiment of the present invention. [Figure 10] FIG. 11 is a cross-sectional view of a tremie tube according to another embodiment of the present invention. [Figure 11] FIG. 11 is a diagram of a tremie tube according to another embodiment of the present invention. [Figure 12] FIG. 11 is a cross-sectional view of a tremie tube according to another embodiment of the present invention. [Figure 13] FIG. 11 is a cross-sectional view of a tremie tube according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] [Embodiment 1] Hereinafter, a tremie pipe according to one embodiment of the present invention will be described with reference to Fig. 1 to Fig. 3. 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 dumping soil and sand into water, and is used in construction work for constructing a structure on the bottom of the water using the soil and sand. As a specific example, it is used in construction work such as backfilling of excavated areas on the seabed, land reclamation in ports, and shallow area construction.

[0036] As described later, the tremie pipe 1A efficiently flows down viscous materials such as calcia-improved soil while suppressing the generation of pollution. For this reason, as shown in Fig. 1, the tremie pipe 1A is equipped with a pipe 10 and a hopper 20. Note that the tremie pipe 1A can be applied not only to viscous materials but also to materials such as soil, sand, and rock rubble.

[0037] (1) Pipe 10 The pipe 10 is, for example, a pipe body installed vertically underwater (for example, in the sea), with both ends constituted by an upper end and a lower end, and when installed vertically, the upper end 12 (one pipe end) is located above the water (in the air) and the lower end 14 (the other pipe end) faces the bottom of the water. In the following, the part of the pipe body including the upper end 12 is referred to as the upper end 101, and the part of the pipe body including the lower end 14 is referred to as the lower end 102.

[0038] <Top end 101> When the tube 10 is placed underwater so that the upper end 101 is in the air, the upper end 101 has a plurality of inlets 17 at a position straddling the water surface, and the plurality of inlets 17 are arranged in a line along the circumferential direction of the tube 10.

[0039] The inlets 17 are openings provided through the wall of the tube 10, and each inlet 17 has a predetermined length along the tube axial direction so as to straddle the water surface as shown in Fig. 1. That is, each inlet 17 has an air opening region 171 that opens in the air on the side closer to the upper end, and an underwater opening region 172 that opens in the water on the side away from the upper end. Air can flow in and out of the tube 10 through the air opening region 171, and water (seawater) can flow in and out of the tube 10 through the underwater opening region 172.

[0040] There is no particular limit to the number of inlets 17. As described later, considering that it is preferable to allow a large amount of seawater to flow into the upper part of the lump of viscous material dropped into the upper end 101, it is better that the size of the inlets 17 on the circumferential surface of the pipe 10 is large, but if they are too large, problems will occur in terms of the strength of the pipe. Therefore, it is preferable to install as many inlets 17 as possible within a range that does not cause problems in terms of strength. For example, in the example of FIG. 1, eight inlets 17 (only four are shown in the figure because FIG. 1 is a front view) are provided at intervals of about 45° along the circumferential direction centered on the axis of the pipe. In other words, it is not the number of inlets 17 that matters, but rather the width of the inlets 17 along the circumferential direction of the pipe 10 (which can also be called the opening width) that matters. Therefore, for example, there may be two inlets 17 that open long along the circumferential direction of the pipe 10.

[0041] The inlet 17 will be further described with reference to Fig. 2. Fig. 2 is an enlarged cross-sectional view of region A shown in Fig. 1, showing the cross-section of the pipe 10 cut along the pipe axial direction. For ease of explanation, Fig. 2 also shows a mass 200 of viscous material flowing down the pipe 10.

[0042] In each inlet 17, an air opening region 171 and an underwater opening region 172 are adjacent to each other and continuous along the pipe axial direction. Furthermore, as shown in Fig. 2, an inclined surface 17a inclined toward the outside upstream direction of the material flow inside the pipe 10 is provided at the edge portion on the downstream side of the material flow direction of each inlet 17. By providing the inclined surface 17a, the corner facing the inside of the pipe 10 is an obtuse angle, so that dispersion of the material lump 200 when it comes into contact with the edge corner can be suppressed compared to when the angle is an acute angle.

[0043] As described later, in order to allow the lump 200 to flow smoothly down at the upper end 101 and increase the flow speed, in this embodiment, the opening size of the inlet 17 is set as follows so that water (seawater) flows in from the inlet 17 within about 10 seconds after the material charged at the upper end 101 reaches the water surface (sea surface).

[0044] (Opening width of inlet 17) The length (opening width) of the inlets 17 along the circumferential direction of the tube 10 is set so that the total opening widths of the inlets 17 account for approximately 70% of the total circumference of the tube 10. However, while not limited to this value, it is preferable that the total opening widths of the inlets 17 account for at least approximately 30% of the total circumference of the tube 10, considering that a large amount of seawater will flow into the upper part of the mass 200.

[0045] In this embodiment, a grab bucket or a backhoe bucket can be used as a method of feeding material into the hopper 20 (FIG. 1) of the tremie pipe 1A, and it is preferable to use a bucket of a size appropriate for the diameter of the tremie pipe 1A. Alternatively, the feeding amount is adjusted with the bucket. The feeding amount with the bucket may be assumed to be in the range of 0.8 to 1.5 times the volume of the spherical lump of material calculated from the inner diameter of the tremie pipe 1A.

[0046] In this embodiment, the inner diameter of the pipe 10 of the tremie pipe 1A can be about 800 to 3000 mm, but is not limited to this value. The length of the pipe 10 is not particularly limited, but can be about 2000 mm, but may be a relatively long pipe length of 10000 mm or more.

[0047] (Length of inlet 17) The length of the inlet 17 along the pipe axial direction is desirably equal to or less than the inner diameter of the pipe 10. This allows water to flow above the lump of viscous material dropped into the pipe 10.

[0048] <Lower end 102> As shown in FIG. 1, the lower end portion 102 is a region that continues to the lower end side of the upper end portion 101 of the tube 10 along the tube axial direction.

[0049] At the lower end 102, slits 16 extending along the axial direction of the pipe 10 are provided at at least two different positions along the circumferential direction of the pipe 10. These slits 16 are located underwater. Each of these slits 16 has a slit length that is equal to or greater than the diameter of the pipe 10. This will be described in detail below.

[0050] The slits 16 provided in the pipe 10 are openings provided penetrating the pipe wall of the pipe 10, and seawater can move freely between the inside and outside of the pipe 10 at the slits 16. In addition, air inside the pipe 10 can be discharged to the outside of the pipe 10 through the slits 16.

[0051] The slit 16 is a long and thin slit. By providing the slit 16, the area of ​​the inner circumferential surface of the lower end 102 of the tube 10 is smaller by the opening area of ​​the slit 16 than when the slit 16 is not provided. In other words, the area of ​​the lower end 102 of the tube 10 that comes into contact with the viscous material is smaller by the opening area. This can reduce the frictional resistance of the viscous material and suppress clogging.

[0052] Eight slits 16 are provided along the circumferential direction of the tube 10. Specifically, the eight slits 16 are provided at intervals of about 45° along the circumferential direction centered on the tube axis. The number of slits 16 is not limited to eight, and may be provided at multiple different positions along the circumferential direction of the tube 10. For example, the number may be appropriately set according to the tube diameter of the tube 10 and the slit width of the slits 16 described later. The multiple slits 16 do not have to be evenly arranged along the circumferential direction, but it is preferable that they are evenly arranged along the circumferential direction. In addition, the start positions of the multiple slits 16 provided along the circumferential direction may be different start positions, and the slits 16 do not have to have the same width.

[0053] Furthermore, similar to the inlet 17, an inclined surface (not shown) similar to the inclined surface 17a may be provided on the edge portion on the downstream side in the material flow direction of the slit 16, which is inclined toward the upstream outward direction with respect to the material flow direction inside the pipe 10. By providing the inclined surface, the corner facing the inside of the pipe 10 is an obtuse angle, so that dispersion of the lump 200 of material when it comes into contact with the corner of the edge portion can be suppressed compared to when the angle is an acute angle.

[0054] As described later, in order for the lump 200 to smoothly flow down at the lower end 102, in this embodiment, the opening size of the slit 16 is specified as follows.

[0055] (Slit length of slit 16) The slit length (one slit length) of each of the slits 16 is set to be equal to or greater than the pipe diameter of the pipe 10. As a result, even if the viscous material is a lump 200 having a diameter substantially equal to the pipe diameter of the tremie pipe 1A, seawater can be circulated and air can be discharged at the upper and lower parts of the lump 200, allowing the lump 200 to flow down the pipe 10 without clogging.

[0056] In this embodiment, as an example, the length of one slit is set to about 75% of the entire length of the pipe 10, that is, the length between the upper end 12 and the lower end 14. This forms a relatively long slit-shaped opening in the pipe 10, which contributes to an even smoother flow down of the mass 200. However, it is not limited to these numerical values. For example, it is preferable that the slit length (one slit length) of each slit 16 is at least 20% of the entire length of the pipe 10.

[0057] (Slit width of slit 16) The length of each slit 16 along the circumferential direction of the pipe 10, i.e., the so-called slit width, is preferably 20 mm or less from the viewpoints of circulating seawater as the lump of viscous material 200 flows down, reducing the contact area between the lump of viscous material 200 and the soil lump of viscous material, while suppressing the outflow of the input material to the outside of the pipe. As an example, the slit width can be 10 mm. However, it is not limited to these values ​​and may be set according to the properties of the target viscous material.

[0058] Here, comparing the slit width of the slit 16 with the opening width of the inlet 17, the total length of the opening widths of the inlets 17 along the circumferential direction of the pipe 10 is greater than the total length of the slit widths of the slits 16. This point will be described later.

[0059] (2) Functions of the inlet 17 and the slit 16 The advantages of providing the inflow ports 17 and slits 16 in the pipe 10 will be described with reference to Figure 3. Figure 3 is a cross-sectional view of the pipe 10 of the tremie pipe 1A, cut vertically along the axial direction of the pipe 10. For ease of explanation, Figure 3 shows only two of the multiple inflow ports 17 and two of the multiple slits 16.

[0060] FIG. 3 shows the state in chronological order from the left end to the right end of the paper. The state shown on the left side shows the state immediately after the viscous material is dropped into the upper end 101 of the pipe 10. The viscous material becomes a lump 200 of a certain size and is dropped from the upper end opening of the pipe 10 to the upper end 101. The dropped lump 200 of the viscous material has a diameter approximately the same as or smaller than the inner diameter of the pipe 10, and flows down by its own weight. Then, when the lump 200 enters the area where the inlet 17 is provided, the air compressed downward as the lump 200 flows down is discharged to the outside of the pipe 10 from the air opening area 171 located on the upstream side of the inlet 17 in the flow-down direction. At the same time, the water (seawater) in the pipe 10 is discharged to the outside of the pipe 10 from the underwater opening area 172 located on the downstream side of the inlet 17 in the flow-down direction. Then, as the lump 200 continues to flow down and is submerged in the water inside the pipe, water outside the pipe is drawn into the pipe from the underwater opening region 172 as the lump 200 flows down underwater. That is, water (seawater) flows from outside the pipe 10 into the upper part of the lump 200 from the underwater opening region 172 of the inlet 17 that opens above the lump 200. At this time, since the inlet 17 opens widely (widely) as described above, a large amount of seawater can be caused to flow from the inlet 17 into the upper part of the lump 200 at the upper end 101, increasing the flow speed, and making it difficult to impede the flowing momentum of the material lump, which is prone to clogging soon after being thrown into the pipe 10.

[0061] At the lower end 102, slits 16 are provided, so that seawater inside the pipe 10 downstream of the mass 200 is discharged outside the pipe 10 through the slits 16, and seawater outside the pipe 10 flows into the pipe 10 upstream of the mass 200 through the slits 16. That is, at the lower end 102, seawater circulates above and below the mass 200. In this way, the flow of water in and out through the slits 16 suppresses the occurrence of pulsation inside the pipe 10, and suppresses the dispersion of the viscous material that makes up the mass 200.

[0062] In addition, in order to promote the descent of the lump of material at the upper end 101, a vibrator that imparts vibrations to the hopper 20 and the pipe 10 may be installed.

[0063] Furthermore, although the tube 10 is a circular tube from the upper end to the lower end, this is not limiting, and the upper end 101 may be a square tube and the lower end 102 may be a circular tube.

[0064] (3) Hopper 20 1, the hopper 20 is connected to the upper end of the pipe 10, has a large opening toward the zenith to facilitate the introduction of the viscous material into the upper end 101 of the pipe 10, and communicates at its lower end with the opening at the upper end of the pipe 10. A known hopper can be used as the hopper 20, but it is also possible to use a hopper having a shape as shown in the embodiment described later.

[0065] Incidentally, a steel grid (for example, grid with spacing of 30 to 100 mm) may be placed over the entire upper end of the hopper 20 so that the material put into the hopper 20 is crushed and enters the pipe 10.

[0066] (4) Materials of each component The pipe 10 can be made of a well-known material used for tremie pipes. For example, a steel pipe or the like can be used. 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 inlet 17 and the slit 16 are provided over a wide area.

[0067] The hopper 20 may be constructed from a material commonly used for constructing hoppers, such as a steel plate.

[0068] (5) Materials and input form The material to be flowed down by the tremie pipe 1A of the present embodiment 1 may be a viscous material selected from the group consisting of calcia-modified soil, clay soil, dredged soil, PS ash-based modified soil, lime-based modified soil, and cement-modified soil. These viscous materials are relatively highly viscous and therefore tend to form lumps, which are difficult to disperse in the sea, but tend to adhere to the inside of the tremie pipe and block the pipe. For this reason, the tremie pipe 1A of the present embodiment 1 is provided with an inlet 17 to suppress the occurrence of blockage without impeding the flow rate of the lumps. Furthermore, in this embodiment, in order to suppress the contact area with the lumps, a plurality of slits 16 are provided, each with a certain length, thereby reducing the area of ​​the inner peripheral surface of the pipe 10 and reducing the area of ​​the surface that may come into contact with the lumps, thereby suppressing the occurrence of blockage.

[0069] However, the tremie pipe 1A can also be used for soil other than the viscous materials exemplified above. For example, sand, rock rubble, and concrete may also be used.

[0070] The viscous material may be intermittently dropped into the pipe 10 so that it forms lumps of a certain size while flowing down the slope 24 of the hopper 20. Therefore, the method of feeding the viscous material into the tremie pipe 1A may be, other than the above-mentioned method of feeding a large amount of the viscous material at once using a bucket, a mode in which small amounts of the viscous material are continuously transported by a belt conveyer and continuously dropped into the hopper 20. As long as the material to be fed has fluidity (for example, a flow value of 8.5 cm or more (NEXCO Test Method, Test Method 313, Test Method for Air Mortar and Air Milk)), any feeding method may be used.

[0071] (6) Construction method of the structure When constructing a structure by depositing a material (viscous material) on the bottom of the water using the tremie pipe 1A, first, the tremie pipe 1A is installed in the water with the lower end 14 of the pipe 10 facing the bottom of the water and the pipe axis aligned vertically. At this time, the tremie pipe 1A is placed in the water so that the upper end 12 of the pipe 10 (FIG. 1) is in the air (installation process). Then, the viscous material is dropped from the hopper 20 into the inside of the tremie pipe 1A thus installed (injection process). The viscous material (soil mass) injected into the pipe 10 flows down inside the pipe 10 (FIG. 2). The viscous material that has reached the bottom of the water is deposited and constructs a structure (construction process). In the process in which the viscous material is deposited on the bottom of the water, the pipe 10 may be gradually raised to the zenith so that the lower end 14 is located near the surface of the deposit on the bottom of the water.

[0072] [Modifications] (Variation 1) A modified example of this embodiment will be described below with reference to Fig. 4. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0073] Fig. 4 is a front view of two aspects of tremie tubes 1B and 1C. Fig. 4 corresponds to Fig. 1 of embodiment 1. For convenience of explanation, the hopper is omitted from the illustration.

[0074] The tremie tube 1B shown on the left side of Fig. 4 has an inlet 17 at an upper end 101 which is different from the inlet 17 in Fig. 1. Specifically, the inlet 17 of the tremie tube 1B is not on the same line as the slit 16, which is different from the inlet 17 and slit 16 in the embodiment shown in Fig. 1, in that the inlet 17 is not on the same line as the slit 16. The total length of the opening widths of the inlets 17 is larger than the total length of the slit widths of the slits 16, and the same effect as that described in the first embodiment is achieved.

[0075] The tremie tube 1C shown on the right side of FIG. 4 has an inlet 17 at the upper end 101, which is different from the inlet 17 in FIG. 1. Specifically, the inlet 17 of the tremie tube 1C has an opening width (length along the circumferential direction of the tube 10) that is approximately the same as the slit width of the slit 16 at the lower end 102. In addition, the inlet 17 of the tremie tube 1C has an interval between adjacent inlets 17 that is narrower than the interval between the slits 16 at the lower end 102. Specifically, the interval between the inlets 17 is approximately half the interval between the slits 16. In other words, the inlets 17 are provided in approximately twice as many units as the slits 16 along the circumferential direction. This allows the inlets 17 to be opened widely in the circumferential direction of the tube at the upper end 101, although the opening width of the inlets 17 is the same as the slit width of the slit 16. This allows a large amount of seawater to flow into the upper part of the lump of material that has just been introduced into the tube 10, as in the first embodiment.

[0076] (Variation 2) Another modified example of this embodiment will be described below with reference to Fig. 5. For ease of explanation, the same reference numerals will be given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0077] Fig. 5 shows a front view of the tremie tube 1Aa. Fig. 5 corresponds to Fig. 1 of the first embodiment. For ease of explanation, the hopper is omitted from the illustration.

[0078] 5, the tremie tube 1Aa has a slit 16 provided in the tube 10 and an inlet 17 that are continuous along the axial direction of the tube. With this configuration, the opening is aligned along the downward flow direction, so that the inflow and outflow of water is uninterrupted, allowing the material to flow downward more smoothly.

[0079] [Embodiment 2] Another embodiment of the present invention will be described below with reference to Fig. 6. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0080] Fig. 6 is a front view of a tremie tube 1D of this embodiment. Fig. 6 corresponds to Fig. 1 of embodiment 1. For ease of explanation, a hopper is omitted from the illustration.

[0081] The tremie tube 1D in Fig. 6 is mainly different from the tremie tube 1A in Fig. 1 in that a slit 16' provided in the lower end 102 of the tube 10 extends to the upper end 101. Details will be described below.

[0082] In the tube 10 of the tremie tube 1D, the slit 16' continues from the lower end 102 to the upper end 101. As a result, when the tremie tube 1D is placed in water with the upper end 12 of the tube 10 in air as shown in Figure 6, a part of the slit 16' that reaches the upper end 101 is open to the air.

[0083] Furthermore, the pipe 10 of the tremie tube 1D has an inflow port 17 located between one slit 16' and another slit 16' along the circumferential direction of the pipe 10 at the upper end 101. The opening width W1 of the inflow port 17 is larger than the slit width W2 of the slit 16'.

[0084] According to the configuration of this embodiment, in addition to the inlet 17, the slit 16' is also open at the upper end 101, realizing a widely open structure, which speeds up the outflow of air from within the tube and allows the material dropped into the tremie tube 1D to flow down quickly.

[0085] [Modifications] In the above-described tremie tube 1D, the opening width W1 of the inlet 17 is larger than the slit width W2 of the slit 16', but this is not limited to this. For example, a modified embodiment shown in Fig. 7 may be used. The modified embodiment will be described below with reference to Fig. 7.

[0086] Fig. 7 is a front view of a tremie tube 1E of this embodiment, which corresponds to Fig. 6 of the above embodiment.

[0087] The pipe 10 of the tremie pipe 1E has an inlet 17 located between one slit 16' and another slit 16' along the circumferential direction of the pipe 10, and the opening width W1 of the inlet 17 is approximately equal to the slit width W2 of the slit 16' (W1 = W2).

[0088] That is, near the water surface, the spacing between the openings in the pipe 10 is about half that in the underwater portion. In the example where eight slits 16' are provided, 16 openings are provided near the water surface, including the inlets 17 and the slits 16'.

[0089] According to the configuration of this embodiment, in addition to the inlet 17, the slit 16' is open near the water surface, realizing a widely opening structure, so that the material can be made to flow down quickly immediately after being dropped into the tremie pipe 1E.

[0090] [Embodiment 3] Another embodiment of the present invention will be described below with reference to Fig. 8. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0091] Fig. 8 is a front view of the tremie tube 1F of this embodiment. Fig. 8 corresponds to Fig. 1 of the first embodiment. For convenience of explanation, the hopper is omitted from the illustration.

[0092] For example, in the tremie pipe 1A of the embodiment shown in Fig. 1, the upper end 101 and the lower end 102 are configured as a single steel pipe, and the inlet 17 and the slit 16 are opened in the steel pipe. In contrast, the tremie pipe 1F of the present embodiment has a configuration in which a first steel pipe 801 and a second steel pipe 802 are connected by a steel plate-like member 804 (connecting member) with a predetermined gap 803 provided. This predetermined gap 803 is the inlet 17F that performs the same function as the inlet 17 described above. The second steel pipe 802, which is the lower end 102, is provided with a slit 16.

[0093] The upper end 101F is composed of a portion including the first steel pipe 801, the upper end of the second steel pipe 802, and the inlet 17F, which is the gap 803. In short, the tremie pipe 1F of this embodiment is configured by connecting two different steel pipes 801, 802 with a steel plate-like member 804, with a predetermined gap 803 as the inlet 17F between the first steel pipe 801 and the second steel pipe 802. The upper end 101 is configured on the first steel pipe 801, and the lower end 102 is configured on the second steel pipe 802. In addition, it is preferable that the plate-like member 804 connects the steel pipes 801 and 802 at their outer circumferential surfaces so as not to impede the flow of the material downward.

[0094] The length or width of the predetermined gap 803 can be adjusted by changing the dimensions of the plate-like member based on a prior charging test for each type of clayey soil to be charged. When the tremie pipe is moved from the construction site to the storage site, it can be easily moved by removing the plate-like member 804 and dividing it into two parts.

[0095] Like the inlet 17 in the first embodiment described above, the inlet 17F has an air opening region 171 that opens in the air on the side closer to the upper end of the tube 10, and an underwater opening region 172 that opens in the water on the side further from the upper end. The air opening region 171 allows air to flow in and out of the tube 10, and the underwater opening region 172 allows water (seawater) to flow in and out of the tube 10.

[0096] The configuration of this embodiment also allows water (seawater) to flow into pipe 10 from inlet 17F, so that even if a large amount of material is dropped from the top of the tremie pipe, water can be made to flow into the top of the mass of material immediately after it is dropped, increasing the flow rate of the mass. This allows the mass to flow smoothly down pipe 10 and does not clog the pipe. In addition, the air compressed below the material when it is dropped from the top of the tremie pipe 1F is discharged outside the pipe from the air opening region 171 of inlet 17F, so it does not impede the flow of the material down.

[0097] [Embodiment 4] Another embodiment of the present invention will be described below with reference to Fig. 9. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0098] In each of the above-described embodiments, the slit 16 is provided in the lower end portion 102 as shown in Fig. 1. However, in one aspect of the present invention, the slit-shaped opening may not be provided. This will be described with reference to Fig. 9.

[0099] 9 is a front view of four modes of tremie tubes 1A', 1B', 1E', and 1F'. For ease of explanation, the hopper is not shown.

[0100] The tremie tube 1A' differs from the tremie tube 1A in Fig. 1 in that it is not provided with the slit 16 present in the tremie tube 1A in Fig. 1. Apart from this difference, it is the same as the tremie tube 1A in Fig. 1.

[0101] The tremie tube 1B' differs from the tremie tube 1B in Fig. 4 in that it is not provided with the slit 16 that is present in the tremie tube 1B in Fig. 4. Apart from this difference, it is the same as the tremie tube 1B in Fig. 4.

[0102] The tremie tube 1E' differs from the tremie tube 1E in Fig. 7 in that it is not provided with the slit 16 present in the tremie tube 1E in Fig. 7. Apart from this difference, it is the same as the tremie tube 1E in Fig. 7.

[0103] The tremie tube 1F' differs from the tremie tube 1F in Fig. 8 in that it is not provided with the slit 16 that is present in the tremie tube 1F in Fig. 8. Apart from this difference, it is the same as the tremie tube 1F in Fig. 8.

[0104] Even in the embodiment exemplified above, since the inlet 17 (inlet 17F) is provided at a position straddling the water surface, a large amount of seawater can be made to flow above the lump of material immediately after it is introduced into the pipe 10. This increases the flow rate of the lump, preventing clogging and allowing the lump to flow smoothly down.

[0105] [Embodiment 5] Another embodiment of the present invention will be described below with reference to Fig. 10. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0106] FIG. 10 is a longitudinal sectional view of the tremie tube 1G of this embodiment taken along the tube axial direction.

[0107] The tremie pipe 1G differs from the tremie pipes of the previously described embodiments and modified examples in that, whereas the tremie pipes have a single pipe structure, the tremie pipe 1G has a double pipe structure in which, for example, pipe 10 of the tremie pipe 1A of embodiment 1 is used as an inner pipe, and an outer pipe 30 (pollution prevention pipe) is further provided along the outer circumferential surface thereof.

[0108] The outer pipe 30 is provided to prevent the diffusion of contamination originating from the viscous material that has escaped from the pipe 10 through the inlet 17 and slits 16 of the pipe 10 corresponding to the inner pipe.

[0109] The outer peripheral surface of the pipe 10 and the inner peripheral surface of the outer pipe 30 are spaced apart. As shown in FIG. 10, when a lump 200 of viscous material flows down inside the pipe 10, seawater discharged outside the pipe 10 through the inlet 17 and the slit 16 flows into the pipe 10 through the inlet 17 and the slit 16 at the upstream side of the lump along the spaced apart portion. Since a circulating flow can be formed in this way, even if the seawater discharged from the pipe 10 is contaminated due to the viscous material, the discharge of the contaminated seawater outside the pipe 30 can be suppressed and the contaminated seawater can be returned to the pipe 10 again. In order to generate this circulation, it is preferable that the outer peripheral surface of the pipe 10 and the inner peripheral surface of the outer pipe 30 are spaced apart by 2 m or more. If the outer peripheral surface of the pipe 10 and the inner peripheral surface of the outer pipe 30 are close to each other, the amount of water (seawater) flowing in from the inlet is small when the lump 200 falls, and pulsation occurs, making it easy for material separation to occur. Therefore, it is preferable that the outer peripheral surface of the tube 10 and the inner peripheral surface of the outer tube 30 are spaced apart by a sufficient distance.

[0110] The outer tube 30 has an upper end at or above the water surface, and its lower end needs only to cover the slit 26 of the tube 10, but may also have a length sufficient to cover the lower end 102 of the tube 10.

[0111] The outer pipe 30 can be made of a steel pipe, similar to the pipe 10 which corresponds to the inner pipe.

[0112] In this embodiment, similarly to the first embodiment, the hopper 20 (not shown in FIG. 10) is connected to the upper end of the tube 10.

[0113] The upper end side of the tube 10 and the upper end side of the outer tube 30 may be spaced apart as shown in FIG. 10, or the tube 10 and the outer tube 30 may be sealed near their upper ends by a lid portion, and an air vent or the like may be provided in the lid portion.

[0114] A contamination prevention film may be provided at the lower end of the outer tube 30. Furthermore, a weight may be provided at the end of the contamination prevention film.

[0115] [Modifications] The above-mentioned tremie pipe 1G has a double pipe structure with an outer steel pipe 30, but the present invention is not limited to this embodiment, and instead of the outer pipe 30, a pollution prevention frame or a pollution prevention film may be installed around the pipe 10 to form a double structure of either of these and the pipe 10. Fig. 11 shows an embodiment equipped with a pollution prevention frame 40.

[0116] The upper part of Fig. 11 is a plan view of a double structure of a pollution prevention frame 40 and a pipe 10. As an example, the pollution prevention frame 40 has a rectangular structure in plan view. Fig. 11(b) shows the double structure cut along the cutting line XX' shown in Fig. 11(a). As with the double pipe structure shown in Fig. 10, it is preferable that the outer peripheral surface of the pipe 10 and the inner peripheral surface of the pollution prevention frame 40 are separated by a sufficient distance.

[0117] In the present modified embodiment, like the above-described tremie pipe 1G, the diffusion of contamination can be suppressed, and environmental considerations can be given to the environment.

[0118] It should be noted that a contamination prevention film may be used instead of the contamination prevention frame 40 having a frame structure as in this modified example. In this case, the contamination prevention film may be made of a resin such as polyethylene or polypropylene.

[0119] [Embodiment 6] Another embodiment of the present invention will be described below with reference to Fig. 12. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0120] In the tremie pipe 1H of this embodiment, when the pipe 10 is placed underwater so that the upper end 12 (one pipe end) of the pipe 10 is in the air, a number of inlets 17 located underwater are lined up along the circumferential direction of the pipe. In this embodiment, the upper end portions 17b of the multiple inlets 17 are located on the water surface.

[0121] Moreover, the tremie tube 1H of the present embodiment has a slit 16 located underwater, similar to the tremie tube 1A of the previously described embodiment 1. That is, the difference is that the position of the inlet 17 is different from the position of the inlet in the previously described embodiment.

[0122] As in this embodiment, if the inlet 17 is located near the water surface even when it is underwater, water (e.g., seawater) can be made to flow from the inlet 17 onto the top of the lump of material immediately after the material is dropped into the tremie pipe 1H and reaches the water surface. In addition, air that enters the pipe together with the material when it is dropped can be quickly discharged from the pipe through the inlet 17. Here, as shown in FIG. 12, the opening width W 17 is the slit width W of slit 16 16 Therefore, a large amount of water can flow into the upper part of the material block immediately after the material is poured into the tremie pipe.

[0123] Regarding the position of the inlet 17, the upper end portion 17b of the inlet 17 is preferably at the same position (height) as the water surface. However, when the tremie pipe 1H is installed in the sea, the sea surface moves up and down due to the influence of waves, but the upper end portion 17b and the water surface do not need to be at the same position all the time. For example, the upper end portion 17b may be below the water surface. Even if the upper end portion 17b is located below the water surface in this way, the above-mentioned effect can be achieved as long as it is near the water surface.

[0124] (Modification) The inlet 17 of the tremie tube 1H′ shown in FIG. 13 has an opening width W 17b is the opening width W of the lower end portion 17c 17c It is tapered and configured larger than

[0125] Since the taper is wider at the top end 17b, water and air circulate efficiently at the top end 17b, which allows a large amount of water to flow from the top end 17b of the inlet 17 to the top of the lump of material immediately after it reaches the water surface, preventing clogging and promoting efficient flow down.

[0126] Although not shown, the slits 16 may also have a shape in which the width of each slit 16 is not uniform but is wider on the upper end 12 side of the tube 10 and narrower on the lower end 14 side.

[0127] The present invention is not limited to the above-described embodiments and modifications, and various modifications are possible within the scope of the claims. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments and modifications. [Explanation of symbols]

[0128] 1A, 1Aa, 1A´, 1B, 1B´, 1C, 1D, 1E, 1E´, 1F, 1F´, 1G, 1H, 1H´ Tremy tube 10 tubes 12 Top 14 Bottom edge 16 Slit 17, 17F inlet 17a Slope 17b Upper end 17c Bottom end 20 Hopper 30 outer tube 40 Pollution Prevention Frame 101, 101F upper end 102 Lower end 171 Air opening area 172 Underwater opening area 200 chunks 801,802 Steel pipe 803 Specified gap 804 Plate-shaped members (connecting members)

Claims

1. A tremie pipe in which material flows down the inside of the pipe, The pipe is placed in water so that one end of the pipe is in air, It has multiple inlets across the water surface, The plurality of inlets are arranged in a line along a circumferential direction of the pipe, The pipe is placed in water so that one end of the pipe is in air, The tube has a plurality of slits extending along the tube axis of the tube, each of which has a portion in air and a remaining portion in water or a whole portion in water; The plurality of slits are provided along a circumferential direction of the pipe, the tube includes an upper end portion including the one tube end and a lower end portion including the tube end opposite to the one tube end, the lower end portion being a region continuing to the opposite tube end side along a tube axis direction of the upper end portion, the inlet portion being provided only in the upper end portion, and the slit being provided at least in the lower end portion, The total length of the opening widths of the inlets along the circumferential direction of the pipe is greater than the total length of the slit widths of the slits. Ptolemie tube.

2. A tremie pipe in which material flows down the inside of the pipe, The pipe is placed in water so that one end of the pipe is in air, a plurality of inlets positioned underwater; The upper ends of the plurality of inlets are located at or just below the water surface, The plurality of inlets are arranged in a line along a circumferential direction of the pipe, The pipe is placed in water so that one end of the pipe is in air, The tube is The pipe has a plurality of slits extending along the pipe axis direction and positioned underwater, The plurality of slits are provided along a circumferential direction of the pipe, the tube includes an upper end portion including the one tube end and a lower end portion including the tube end opposite to the one tube end, the lower end portion being a region continuing to the opposite tube end side along a tube axis direction of the upper end portion, the inlet portion being provided only in the upper end portion, and the slit being provided at least in the lower end portion, The total length of the opening widths of the inlets along the circumferential direction of the pipe is greater than the total length of the slit widths of the slits. Ptolemie tube.

3. The slit length of each of the slits is equal to or greater than the diameter of the pipe. The tremie tube according to claim 1 or 2.

4. Each of the inlets is located between one of the slits and another of the slits. The tremie tube according to claim 1 or 2.

5. The pipe is configured such that a gap of a predetermined length is provided between a first steel pipe and a second steel pipe along the pipe axis direction, and the first steel pipe and the second steel pipe are connected by a plurality of connecting members arranged along the circumferential direction of the pipe, The gap is divided in the circumferential direction of the pipe by the plurality of connecting members, and each divided gap constitutes the inflow port. A tremie tube according to any one of claims 1 to 3.

6. A tremie pipe in which material flows down the inside of the pipe, The pipe is placed in water so that one end of the pipe is in air, It has multiple inlets across the water surface, The plurality of inlets are arranged in a line along a circumferential direction of the pipe, The pipe is configured such that a gap of a predetermined length is provided between a first steel pipe and a second steel pipe along the pipe axis direction, and the first steel pipe and the second steel pipe are connected by a plurality of connecting members arranged along the circumferential direction of the pipe, The gap is divided in the circumferential direction of the pipe by the plurality of connecting members, and each divided gap constitutes the inflow port. Ptolemie tube.

7. A tremie pipe in which material flows down the inside of the pipe, The pipe is placed in water so that one end of the pipe is in air, a plurality of inlets positioned underwater; The upper ends of the plurality of inlets are located at or just below the water surface, The plurality of inlets are arranged in a line along a circumferential direction of the pipe, The pipe is configured such that a gap of a predetermined length is provided between a first steel pipe and a second steel pipe along the pipe axis direction, and the first steel pipe and the second steel pipe are connected by a plurality of connecting members arranged along the circumferential direction of the pipe, The gap is divided in the circumferential direction of the pipe by the plurality of connecting members, and each divided gap constitutes the inflow port. Ptolemie tube.

8. The tube is The pipe has a plurality of slits extending along the pipe axis direction and positioned underwater, The plurality of slits are provided along the circumferential direction of the pipe. The tremie tube according to claim 6 or 7.

9. A pollution prevention pipe is provided in the area below the water surface on the outer periphery of the pipe, forming a double pipe structure. A tremie tube according to any one of claims 1 to 8.

10. A pollution prevention frame or a pollution prevention film is provided in the area below the water surface on the outer periphery of the pipe. A tremie tube according to any one of claims 1 to 8.

11. A method for constructing a structure by depositing a material, comprising the steps of: An installation step of installing the tremie tube according to any one of claims 1 to 10 in water so that one end of the tube is in air; a charging step of charging a material into the tremie pipe installed in the installation step; a construction process in which the material introduced in the introduction process is dropped from the pipe into water and cast in a predetermined location to construct the structure; Construction methods including.

12. The material is selected from the group consisting of calcia-modified soil, clay soil, dredged soil, PS ash-based modified soil, lime-based modified soil, and cement-modified soil; The construction method according to claim 11.

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