Structure and construction method of tremie pipes for dumping soil, sand, and rock waste.

Abstract

To provide a structure of a tremie pipe for sediment / rock muck input.SOLUTION: In a structure (1) of a tremie pipe for sediment / rock muck input, a tremie pipe (10) and a hopper (20) are connected to each other, the tremie pipe (10) has a first part (10A) whose inside and outside do not communicate with each other, and a second part (10B) having openings (16), the end on a water bottom side of the first part (10A) is deeper than a water depth of 2 m, and the openings (16) extend in a slit shape in a pipe axis direction in at least two parts in a circumferential direction of the tremie pipe.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to the structure of a tremie pipe for filling earth and sandstone and a construction method of a structure.

Background Art

[0002] In works such as backfilling deep excavation traces of seabed ground and landfill, submerged breakwater construction, and shallow area creation in harbors, a tremie pipe may be used when filling earth and sand into a predetermined location on the seabed. At that time, the tremie pipe is arranged in the sea with the upper end above the water surface and the lower end facing the seabed, and earth and sand are input from the upper end via a hopper or the like. By using such a tremie pipe, the generation of pollution in the sea can be suppressed and the environment can be considered. As such a tremie pipe, a tremie pipe composed of a double pipe in which an outer pipe having a larger pipe diameter and pipe length than an inner pipe is arranged around an inner pipe having an opening near the static water surface is disclosed (Patent Documents 1 to 2). Also, a tremie pipe provided with a water intake below the water surface is disclosed even in a configuration that is not a double pipe (Patent Document 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the conventional techniques described above have several drawbacks. When soil or other materials are introduced into the tremie pipe, the impact of the materials falling onto the water surface and the pulsation of the water within the tremie pipe cause fluctuations in the water level, leading to significant turbidity. Additionally, a large amount of bubbles are generated in the water within the tremie pipe, and as these bubbles diffuse into the water, the soil and other materials are dispersed, easily causing water pollution. Regarding these bubbles, one possible solution is to install a chamber with a screw conveyor, water intake, and air vent pipe in the tremie pipe, as described in Patent Document 3, but this would require a large-scale apparatus.

[0005] Therefore, one aspect of the present invention aims to realize a structure for a tremie pipe for depositing soil and rock rubble, which is used to deposit soil and rock rubble with low viscosity into water, and a construction method for the structure that can suppress the diffusion of soil and rock rubble into the surrounding water area. [Means for solving the problem]

[0006] To solve the above problems, a structure of a tremie pipe for loading soil and rock waste according to one aspect of the present invention comprises a tremie pipe and a hopper connected to the tremie pipe, wherein soil or rock waste is loaded into the tremie pipe from one end via the hopper and discharged from the other end, wherein the tremie pipe has a first portion in which the inside and outside of the pipe are not in communication on the side surface, and a second portion having an opening in which the inside and outside of the pipe are in communication on the side surface, the tremie pipe is positioned in a predetermined body of water with one end facing upward and the other end facing the bottom, the one end is composed of the first portion, the bottom end of the first portion is at a depth of 2 meters or more, the second portion is located closer to the bottom than the first portion, and the opening extends in a slit shape along the pipe axis direction at least at two locations in the circumferential direction of the tremie pipe.

[0007] According to the above configuration, the first section, which does not have an opening connecting the inside and outside of the pipe, is present at least up to a water depth of 2 meters. This prevents the sediment or rubble immediately after being introduced into the water from undesirably spreading to the surrounding area near the water surface. In other words, the first section plays the role of a conventional pollution control membrane or pollution control frame. Therefore, a pollution control membrane or the like, which would be necessary if an opening were provided near the water surface, becomes unnecessary, and the device can be made large-scale while suppressing pollution during introduction and guiding low-viscosity sediment or rubble to the other end of the tremie pipe.

[0008] Furthermore, according to the above configuration, the second portion, which is located closer to the seabed than the first portion, has a slit-shaped opening. This allows water to flow into the pipe from the opening, and together with the water flow into the pipe from the other end of the tremie pipe, it promotes the falling of soil or rock debris inside the pipe and suppresses blockage inside the pipe.

[0009] In one aspect of the present invention, the structure of a tremie pipe for dumping soil and rock is such that, in the above configuration, the length of the underwater portion of the tremie pipe is 50% to 90% of the water depth of the predetermined water area, and the other end of the tremie pipe is composed of the second portion.

[0010] According to the above configuration, a second section having a slit-shaped opening is provided on the seabed side at a depth of at least 2m, allowing water to flow into the pipe at that point to promote the falling of sediment or rubble while suppressing the generation of pulsations within the pipe.

[0011] In one aspect of the present invention, the structure of a tremie pipe for loading soil and rock is such that the width of the slit in the opening is at least 5 mm.

[0012] According to the above configuration, soil and rock debris falling inside the tremie pipe are less likely to flow out of the pipe, and water from outside the pipe can be efficiently drawn into the pipe.

[0013] In one aspect of the present invention, the structure of a tremie pipe for loading soil and rock is as follows: In the above configuration, the hopper has an inner slope that forms a V-shape in cross-section, and an outlet communicating with the inside of the tremie pipe is provided at the lower end of the inner slope, and the outlet is located underwater.

[0014] According to the above configuration, soil or rubble can be allowed to flow down on the hopper and slide into the tremie pipe, thereby suppressing impact and pulsation when it falls onto the water surface, and preventing air from being entrained when the soil or rubble is introduced into the water.

[0015] In one aspect of the present invention, the structure of a tremie pipe for loading soil and rock is such that the connection between the tremie pipe and the hopper is below the water surface.

[0016] According to the above configuration, soil or rubble can be slid underwater on the hopper and then introduced into the tremie pipe, thereby suppressing impact and pulsation when the material falls onto the water surface, as well as the entrainment of air when the soil or rubble is introduced underwater.

[0017] In one aspect of the present invention, the structure of a tremie pipe for loading soil and rock is configured such that the other end of the pipe has a reinforcing portion on the outer circumferential surface of the second portion.

[0018] According to the above configuration, the presence of a reinforcing portion prevents deformation of the tremie tube even if the other end of the tube is notched by the opening.

[0019] To solve the above problems, a construction method for a structure according to one aspect of the present invention involves constructing a structure by dumping soil or rock debris into water using the structure of a tremie pipe for dumping soil and rock debris as described above.

[0020] According to the above method, by using a tremie pipe having the structure of the tremie pipe for earth and rock slush input described above, it is easier to control the dropping position of earth and sand or rock slush into the water (bottom of the water) compared to input by bottom opening purge or surface water input by grab, and it is possible to satisfactorily drop earth and sand or rock slush into the water (bottom of the water) while suppressing pollution to the surroundings during input.

Effect of the Invention

[0021] According to one aspect of the present invention, without large-scaling the device, it is possible to suppress pollution during input and guide earth and sand or rock slush with low viscosity to the other pipe end of the tremie pipe.

Brief Description of the Drawings

[0022] [Figure 1] It is a graph showing the difference in the pollution generation source unit according to the method of inputting earth and sand into water. [Figure 2] It is a side view of the structure of the tremie pipe for earth and rock slush input according to an embodiment of the present invention. [Figure 3] It is a cross-sectional view when the second part of the tremie pipe shown in FIG. 2 is cut along a direction perpendicular to the pipe axis direction. [Figure 4] It is a cross-sectional view when the second part of the tremie pipe shown in FIG. 2 is cut along the pipe axis direction, and it is a cross-sectional view showing the shape of the opening. [Figure 5] It is a diagram showing the structure of a hopper connected to the tremie pipe for earth and rock slush input shown in FIG. 2, (a) is a plan view, (b) is a cross-sectional view taken along the cutting line A-A' in (a), (c) is a modified example of (b), (d) is a plan view of a modified example of the hopper, and (e) is a cross-sectional view taken along the cutting line B-B' in (d). [Figure 6] It is a side view showing two different examples of the positional relationship between the hopper provided in the structure of the tremie pipe for earth and rock slush input shown in FIG. 2 and the water surface. [Figure 7] It is a diagram for explaining the configuration of the hopper provided in the tremie pipe for earth and rock slush input shown in FIG. 2. [Figure 8]This figure illustrates a construction method for a structure using the tremie pipe structure for loading soil and rock, as shown in Figure 2. [Figure 9] This figure illustrates a modified construction method for a structure using the tremie pipe structure for loading soil and rock, as shown in Figure 2. [Figure 10] This is a side view of the structure of a tremie pipe for loading soil and rock waste according to another embodiment of the present invention. [Modes for carrying out the invention]

[0023] [Embodiment 1] In recent years, methods for loading soil and sand into port construction include loading by soil carriers, loading by grabs, and loading by tremie. Comparing the pollution intensity of each loading method in the graph shown in Figure 1, it can be seen that loading by soil carriers, which loads directly into a designated water area, generates significantly more turbidity in the water compared to other loading methods. On the other hand, loading by grabs, which is expected to have a pollution-suppressing effect by lowering the grab into the water and loading soil and sand near the seabed, has the problem of low work efficiency. Compared to these loading methods, loading by tremie, in which soil and sand fall through a tremie pipe installed at the target loading position on the seabed, can be said to achieve efficient loading with reduced pollution. As an example of tremie loading, there is a method of introducing water from the outside to prevent blockage inside the pipe, and the inventors are conducting research and development on a tremie pipe with an opening in the pipe body for introducing water. Therefore, the inventors have discovered a tremie pipe structure that allows for efficient injection of low-viscosity soil or rubble while suppressing pollution generation, and have completed one embodiment of the present invention. Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0024] (Structure of a tremie pipe used for dumping soil, sand, and rock waste) Figure 2 is a side view of the structure of a tremie pipe for loading soil and rock in one embodiment of the present invention. Structure 1 of the tremie pipe for loading soil and rock comprises a tremie pipe 10 and a hopper 20 connected to the tremie pipe 10. Structure 1 of the tremie pipe for loading soil and rock allows soil or rock to be loaded into the tremie pipe 10 from one pipe end 12 via the hopper 20 and discharged from the other pipe end 14.

[0025] (Ptolemy tube 10) When dumping soil and rubble, the tremie pipe 10 is positioned in a predetermined body of water with one end 12 near the water surface and the other end 14 facing the seabed WG. When positioned in the predetermined body of water, the axial direction of the tremie pipe 10 is approximately parallel to the vertical direction. Below, the specific configuration of the tremie pipe 10 and the positional relationships between its components will be explained based on the tremie pipe 10 positioned in the predetermined body of water in this manner.

[0026] The tremie pipe 10 has a first portion 10A on its side where the inside and outside of the pipe are not in communication, and a second portion 10B on its side which has an opening 16 where the inside and outside of the pipe are in communication. The tremie pipe 10 is formed by the first portion 10A on one end 12 side of the pipe.

[0027] The first part 10A can be described as a part on the circumferential surface (side) of the pipe body in which no openings are provided at all. The term "opening" here refers to any opening that allows water to flow from the outside of the pipe into the pipe from the circumferential surface of the pipe body, or from the inside of the pipe out of the pipe, regardless of whether it is the same shape as the opening 16 provided in the second part 10B.

[0028] The bottom-facing end of the first section 10A (the boundary between the first section 10A and the second section 10B) is located at a depth of 2 meters or more. This means that the bottom-facing end of the first section 10A may be located at a depth greater than 2 meters. In short, the tremie tube 10 has no openings in the range from the water surface to a depth of at least 2 meters.

[0029] Here, one end 12 of the tremie pipe 10 may be at the same level as the water surface or below the water surface, but it is more preferable for it to be below the water surface. Below the water surface is the range from the water surface to a depth of 1 meter. If one end 12 is at approximately the same level as the water surface, the axial length of the first section 10A is at least 2 meters from the water surface to a depth of 2 meters. As another example, if one end 12 is below the water surface, then at least the range from that end 12 to a depth of 2 meters should be the first section 10A.

[0030] In another example, if the configuration of one end 12 of the tremie pipe 10 allows the lower end of the hopper 20 to communicate underwater, then the one end 12 itself may be located above the water surface near the water surface. For example, one end 12 of the tremie pipe 10 may have a notched section that extends towards the bottom, into which the hopper is fitted. In this case, the water surface is located slightly below the one end 12, and the first section 10A, which does not have an opening, extends at least 2 meters below this water surface.

[0031] The second part 10B is located closer to the seabed WG than the first part 10A, and is on the other end 14 side of the pipe, as shown in Figure 2. Specifically, the other end 14 side of the tremie pipe 10 may be composed of the second part 10B.

[0032] The openings 16 provided in the second section 10B extend in a slit shape along the pipe axis. At least two slit-shaped openings 16 are provided in the circumferential direction of the tremie pipe 10. Figure 3 is a cross-sectional view of the second section 10B cut perpendicular to the pipe axis. As an example, the slit-shaped openings 16 are provided in four circumferential directions of the tremie pipe 10, as shown in Figure 3. Note that the multiple slit-shaped openings 16 do not need to be provided at equal intervals along the circumferential direction of the tremie pipe 10, and may be provided unevenly in the circumferential direction (for example, only the two openings 16 on the lower side in Figure 3). As an example, considering the water flow in a predetermined body of water where the tremie pipe 10 is placed, the openings may not be provided on the side facing the water flow. This configuration makes it possible to suppress the generation of pollution even if water flows through the tremie pipe 10.

[0033] The slit-shaped opening 16 has a width (length along the circumferential direction of the tremie pipe 10) of at least 5 mm. A width of at least 5 mm allows for good water inflow and outflow between the inside and outside of the pipe. Preferably, the width is 20 mm or less. A width of 20 mm or less helps to suppress the outflow of soil or rubble flowing down the tremie pipe 10 to the outside of the pipe.

[0034] Since the slit-shaped opening 16 extends along the pipe axis, it can suppress the dispersion of sediment or rock debris flowing down the pipe. If the longitudinal direction (extension direction) of the opening were inclined or perpendicular to the pipe axis, the flow direction of the sediment or rock debris would intersect with the edge of the slit-shaped opening, causing the flowing sediment or rock debris to disperse in the direction of flow within the pipe by contact with the edge.

[0035] A preferred configuration for the edge of the slit-shaped opening 16 will be described below with reference to Figure 4. Figure 4 is a partial cross-sectional view of the tremie pipe 10, and is a cross-sectional view at the location where the slit-shaped opening 16 is provided. As shown in Figure 4, the lower end of the slit-shaped opening 16 is provided with an inclined surface 16a that slopes upward toward the outside of the pipe. The inclined surface 16a can be formed, for example, by adjusting the angle of the grinder when forming the slit-shaped opening 16 using a grinder. Figure 4 shows how a mass of soil or rubble 500 flows down inside the pipe. Because the slit-shaped opening 16 is provided with an inclined surface 16a, the corner facing inward into the pipe 10 is obtuse. This suppresses the decomposition of the mass when it comes into contact with the corner of the edge, and suppresses the dispersion of soil or rubble, compared to the case where the corner is acute.

[0036] There are no particular restrictions on the axial length of the second section 10B. The second section 10B may be made up of the portion of the underwater part of the tremie pipe 10 excluding the length of the first section 10A, but it is preferable that the axial length of the second section 10B be at least 2 meters.

[0037] The length of the underwater portion of the tremie pipe 10 is 50% to 90% of the water depth of the predetermined body of water where the tremie pipe is placed. This allows for the effective deployment of soil or rubble to the target location. The diameter of the tremie pipe 10 may be 300 mm or more and 2500 mm or less, but is not limited to this. According to this embodiment, efficient deployment is possible by suppressing the dispersion of soil or rubble. Therefore, the diameter of the tremie pipe 10 can be relatively large, for example, about 2000 mm, enabling the deployment of a large amount of soil or rubble at once.

[0038] (Hopper 20) The hopper 20 shown in Figure 2 has an inner slope 26 that forms a V-shape in cross-section. The connection between the tremie pipe 10 and the hopper is below the water level WS. In other words, the connection is submerged in water. In short, the outlet 22, which is located at the lower end of the inner slope 26 and communicates with the inside of the tremie pipe 10, is submerged in water.

[0039] The hopper 20 will be explained using Figure 5. Figure 5(a) is a plan view of the hopper 20. The hopper 20 is provided with an outlet 22 that communicates with one end 12 of the tremie pipe 10. The outlet 22 is located at the corner of the hopper 20 in a plan view. Furthermore, the flow path leading to the outlet 22 in the hopper 20 starts at a position diagonally opposite the outlet 22 in a plan view and slopes downward toward the outlet 22. Specifically, the hopper 20 has a valley shape (V-shaped valley, trapezoidal, or U-shaped valley), and has an inclined surface 26a on one side and an inclined surface 26b on the other side, separated by a ramp 24 corresponding to the bottom of the valley, with the outlet 22 located at one end of the ramp 24. Therefore, the flow path leading to the outlet 22 is configured to start near the zenith end of the inclined surfaces 26a and 26b toward the valley. Furthermore, one end 12 of the tremie pipe 10 is positioned directly below the outlet 22 and is in communication with it. By configuring the hopper 20 in this way, the soil or rubble dropped from the belt conveyor, etc., flows down the channel from the point of entry into the hopper 20 to the outlet 22, and is not directly introduced into the water surface, thus suppressing pulsation and reducing the likelihood of pollution. Here, the hopper 20 also has an inclined channel 24 that is inclined with respect to the horizontal plane, with the outlet 22 located below it. The angle of inclination of the inclined channel 24 with respect to the horizontal plane may be smaller or larger than the angle of inclination of the inclined surfaces 26a and 26b with respect to the horizontal plane. If the angle of inclination of the inclined channel 24 with respect to the horizontal plane is smaller, the soil or rubble that flows down the inclined surface 26a or 26b to the inclined channel 24 will be stored in the inclined channel 24 as it flows to the outlet 22.

[0040] Figure 5(b) also shows a cross-sectional view of the ramp 24. This cross-sectional view is a cross-sectional view taken along the cutting line AA' indicated on the hopper 20 in Figure 5(a). The ramp 24 corresponding to the bottom of the valley may have a V-shape in the cross-sectional view, where the inclined surfaces 26a and 26b intersect. Alternatively, as shown in Figure 5(c), the portion where the inclined surfaces 26a and 26b intersect may be curved to have a U-shape in the cross-sectional view. In this specification, a hopper 20 having a ramp 24 with this V-shape is referred to as a hopper having an inner slope that constitutes a V-shaped cross-section. Furthermore, shapes in which the intersecting portion is curved to form a U-shape, as well as shapes in which the space between the inclined surface 26a and the inclined surface 26b is flat, as shown in the plan view of the modified hopper 20 in Figure 5(d), i.e., the valley bottom is flat as shown in Figure 5(e) (cross-sectional view taken along the cutting line BB' in Figure 5(d)), can also be said to be generally V-shaped. Therefore, in this specification, these are included in hoppers having an inner slope that constitutes a V-shaped cross-section.

[0041] As shown in Figure 2, the hopper 20 has an outlet 22 located underwater, allowing soil or rubble to be slid diagonally into the water. In particular, when the inclined surfaces 26a and 26b have submerged portions, the hopper discharges air between the soil or rubble into the water as it flows down the inclined surfaces 26a and 26b, thereby suppressing the entrainment of air when the soil or rubble falls onto the water surface.

[0042] (Effects of this embodiment) Using Figure 6, the effects of Structure 1 of the tremie pipe for depositing soil and rock in this embodiment will be explained. Figure 6(a) shows a configuration in which one end 12 of the tremie pipe 10 is at approximately the same level as the water surface, and Figure 6(b) shows a configuration in which one end 12 of the tremie pipe 10 is located below the water surface, and a portion of the inclined surfaces 26a and 26b are submerged. Both configurations of Figure 6(a) and (b) are within the scope of this embodiment. In the configurations of Figure 6(a) and (b), Structure 1 of the tremie pipe for depositing soil and rock in is configured such that, as shown in Figure 6, with one end 12 positioned near the water surface WS, the bottom-dwelling end (second part 10B side) of the first part 10A, which is configured on the side of one end 12, is located at a water depth of 2 meters or more. This prevents the soil or rock 500 that has just been deposited into the water by flowing down the hopper 20 from undesirably spreading to the surroundings near the water surface WS. Therefore, the previously required pollution control membranes and frames are no longer necessary, and the equipment can be made large-scale without suppressing pollution, allowing the soil or rubble to flow down to the other end 14 of the tremie pipe. In addition, by providing a slit-shaped opening 16 in the second section 10B, water can flow into the tremie pipe 10 from the opening 16, and together with the inflow and outflow of water into the pipe from the other end 14, the falling of soil or rubble inside the pipe can be promoted and blockage inside the pipe can be suppressed. Furthermore, since the soil or rubble 500 is introduced into the tremie pipe 10 via the hopper 20, the impact of falling onto the water surface or the effects of pulsation as it flows down inside the tremie pipe 10 are suppressed, making it difficult for the soil or rubble to disperse. In particular, compared to the configuration in Figure 6(a), the configuration in Figure 6(b), in which the outlet 22 of the hopper 20 is located in water, can suppress the entrainment of air from the soil or rubble as described above, and can also suppress the dispersion of the soil or rubble 500.

[0043] Here, the effects of Structure 1 of the tremie pipe for loading soil and rock in this embodiment will be explained in comparison with the comparative tremie pipe structures. Figure 7 illustrates four types of tremie pipe structures, with (a) the first comparative structure 1001, (b) the second comparative structure 1002, and (c) the third comparative structure 1003 being comparative structures from the left side of the drawing, and (d) on the far right of the drawing being Structure 1 of the tremie pipe for loading soil and rock in this embodiment. For comparison, all structures have the same pipe diameter and a hopper is connected to the upper end of the tremie pipe.

[0044] In the first comparative structure 1001 shown in Figure 7(a), the tremie pipe 1011 does not have an opening along its entire length. When soil or rubble 500 is introduced into the first comparative structure 1001 with this configuration, it falls directly onto the water surface, causing large pulsations and water level fluctuations as indicated by the arrows, resulting in significant pollution. Furthermore, because there is no opening, water only enters the tremie pipe 1011 from the lower end of the pipe. As a result, the water movement near the lower end of the tremie pipe 1011 increases along with the outflow of water from the pipe due to the discharge of soil or rubble 500, making it easy for the soil or rubble 500 to disperse and for pollution to occur.

[0045] The second comparative structure 1002 in Figure 7(b) is a tremie pipe 1012 that, like the first comparative structure 1001, does not have an opening, and the pipe length itself is also shorter. When soil or rubble 500 is introduced into the second comparative structure 1002, although the pulsation and water level fluctuations are smaller than in the first comparative structure 1001 due to the shorter pipe length, the fine particles of soil or rubble 500 that are quickly discharged from the lower end of the tremie pipe 1012 are dispersed in the water, and the pollution is spread over a wide area by the water flow.

[0046] The third comparative structure 1003 in Figure 7(c) has slit-shaped openings 1063 running along the axial direction of the tremie pipe 1013 for almost its entire length. When soil or rubble 500 is introduced into the third comparative structure 1003 with this configuration, unlike cohesive soil, the soil or rubble has low viscosity, so water flows in and out through the openings 1063 near the water surface, causing pollution and diffusion of the pollution outside the tremie pipe 1013. For this reason, when adopting the third comparative structure 1003, it is necessary to install a pollution control membrane or pollution control frame at least above and below the water surface. Furthermore, because the openings 1063 run for almost the entire length of the tremie pipe 1013, although pulsation and water surface fluctuations are small, pollution diffuses outside the pipe over its entire length.

[0047] In the structure 1 of the tremie pipe for depositing sediment and rock rubble in this embodiment shown in Figure 7(d), although pulsation and water level fluctuations occur more than in the third comparative structure 1003 due to the provision of the first section 10A, pulsation and pollution generation are suppressed and there is no diffusion outside the pipe. In addition, in the structure 1 of the tremie pipe for depositing sediment and rock rubble in this embodiment, a slit-shaped opening 16 is provided in the second section 10B, so that water can flow in and out of the pipe through the opening 16, thereby promoting the flow of sediment or rock rubble 500.

[0048] In this embodiment, the section from one pipe end 12 to the other pipe end 14 is made up of a single straight pipe. However, the present invention is not limited to this, and the straight pipe corresponding to the first section 10A and the straight pipe corresponding to the second section 10B may be connected by a well-known connecting configuration. In this configuration in which multiple straight pipes are connected, the connection point may be located midway along the axial length of the first section 10A, or midway along the axial length of the second section 10B.

[0049] Figure 8 shows a diagram illustrating the construction method of a structure using the Structure 1 of the soil and rock spoil input tremie pipe of this embodiment. Figure 8(a) is a diagram illustrating the construction state, and Figure 8(b) is a step diagram of the construction. The construction method includes the step of installing the soil and rock spoil input tremie pipe 10 in a predetermined body of water (Figure 8(b)S1), and the step of inputting soil or rock spoil into the hopper 20 connected to the installed soil and rock spoil input tremie pipe 10 (Figure 8(b)S2). Regarding the installation in step S1, it includes measuring the water depth at the placement location and setting the axial length (underwater portion) of the tremie pipe 10 based on the measured water depth. The tremie pipe 10 or the Structure 1 of the soil and rock spoil input tremie pipe should be supported by a well-known support mechanism so that its position relative to the water surface is at a predetermined position. Regarding the input in step S2, soil or rock spoil is dropped onto the inner slope 26 (inclined surface) of the hopper 20 using a belt conveyor 100 or the like.

[0050] The belt conveyor 100 mentioned above can be a reclaimer ship or a drop-mixing ship. However, it is not limited to a belt conveyor; soil or rubble may also be fed into the hopper 20 using a grab or backhoe bucket. Furthermore, as shown in Figure 8(a), it is desirable to install the belt conveyor 100 so that the falling soil or rubble 500 falls approximately to the middle of the ramp 24 of the hopper 20.

[0051] (modified version) Figure 9 shows a flowchart of a modified construction method. In this modified method, a step of pre-treatment of the soil or rock debris (Figure 9S2a) is included before the step of loading the soil or rock debris into the tremie pipe structure 1 for soil and rock debris loading (Figure 8(b)S2).

[0052] In step S2a of Figure 9, as a pretreatment step, soil or rubble is placed in a tank or the like beforehand to measure turbidity, etc., and pretreatment is performed if the amount of pollution generated is high. Pretreatment involves spraying or adding and mixing a separation inhibitor to prevent the dispersion of soil or rubble. The separation inhibitor can be sprayed onto the soil or rubble on the belt conveyor 100 in Figure 8(a), or it can be added to the soil or rubble in a soil transport vessel, etc., and then mixed with a backhoe or the like. As the separation inhibitor, well-known acrylic-based, cellulose-based, or other water-soluble polymer-containing separation inhibitors can be used.

[0053] Furthermore, when performing the pretreatment step S2a with a backhoe, a modified form of the one shown in Figure 9 is also considered to be a configuration in which, before or in parallel with the work of installing the tremie pipe 10 for loading soil and rock debris in a predetermined body of water in step S1, the mixing work is performed at another location such as a quay, and the rock debris that has undergone pretreatment step S2a is moved to a storage area for loading into the tremie pipe and then loaded into the tremie pipe 10 in step S2.

[0054] (Soil and rock debris) The target material for using Structure 1 of the tremie pipe for introducing soil, sand, and rock rubble in this embodiment is soil or rock rubble, which have low viscosity and do not easily form lumps. Therefore, when introduced into water, they form lumps to some extent, but water can pass through the inside of these lumps. Here, rock rubble is the residue from the production of stone materials, and there are no particular restrictions on its size, but it is desirable that the maximum particle size be 300 mm.

[0055] As described above, Structure 1 of the tremie pipe for soil and rock spoil is intended for use exclusively with soil or rock spoil. However, any low-viscosity construction material with properties equivalent to soil and rock spoil can be used to fill the tremie pipe for soil and rock spoil using Structure 1.

[0056] [Embodiment 2] Other embodiments of the present invention are described below. For the sake of clarity, components having the same function as those described in the above embodiments will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0057] Figure 10 is a side view of Structure 2 of the tremie pipe for dumping soil and rock according to this embodiment. Structure 2 of the tremie pipe for dumping soil and rock according to this embodiment differs from Structure 1 of the tremie pipe for dumping soil and rock according to Embodiment 1 in that a reinforcing portion 30 is provided on the outer surface of the second portion 10B so as not to deform the other pipe end 14, which extends to the other pipe end 14 of the tremie pipe 10 and is provided by a slit-shaped opening 16 that is cut out of the other pipe end 14. Note that the reinforcing portion 30 may be provided in multiple locations at predetermined distances in the pipe axis direction according to the length of the second portion 10B of the tremie pipe, or it may be provided at least near the other pipe end 14.

[0058] The structure 2 of the tremie pipe for dumping soil and rock in this embodiment also provides the same effects as the structure 1 of the tremie pipe for dumping soil and rock in Embodiment 1. Note that the slit-shaped opening 16 does not extend to the other pipe end 14, and the tremie pipe 10 may be present around the entire circumference of the other pipe end 14.

[0059] Furthermore, according to the configurations of Structure 1 and 2 of the tremie pipe for dumping sediment and rock, as described in Embodiment 1 and Embodiment 2, the generation of pollution into the water can be suppressed. Such effects contribute, for example, to achieving Sustainable Development Goal 14, "Conserve and sustainably use the oceans, seas and marine resources," advocated by the United Nations.

[0060] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of Symbols]

[0061] 1, 2 Structure of a tremie pipe for dumping soil, sand, and rock waste 10 Ptolemy tubes 10A first part 10B Second part 12 One end of the pipe 14 The other end of the pipe 16 Opening 20 hoppers 22 Outlet 24 ramp 26, 26a, 26b Slope (inner slope) 30 Reinforcement section 100 Belt Conveyor 500 soil or rock rubble

Claims

1. A tremie pipe structure for loading soil and rock waste, comprising a tremie pipe and a hopper connected to the tremie pipe, wherein soil or rock waste is fed into the tremie pipe from one end via the hopper and discharged from the other end, The tremie tube has a first portion on its side where the inside and outside of the tube are not in communication, and a second portion on its side which has an opening where the inside and outside of the tube are in communication. The first part and the second part are composed of straight tremie tubes, and both are constructed in a way that prevents deformation. The tremie pipe is positioned in a predetermined body of water with one end near the water surface and the other end facing the bottom. The aforementioned end of the pipe is formed by the first portion, and the bottom-facing end of the first portion is at a depth of 2 meters or more. The second part is located closer to the seabed than the first part, The aforementioned openings are provided in a slit-like manner along the axial direction of the tremie tube at least at two locations in the circumferential direction. Structure of a tremie pipe used for dumping soil, sand, and rock waste.

2. The length of the underwater portion of the tremie tube is 50% to 90% of the water depth of the predetermined body of water. The other end of the tremie tube is formed by the second part. The structure of a tremie pipe for loading soil, sand, and rock waste as described in claim 1.

3. The hopper has an inner slope that forms a V-shape in cross-section, An outlet is provided at the lower end of the inner slope, which communicates with the inside of the tremie pipe. The outlet is located underwater. The structure of a tremie pipe for loading soil, sand, and rock waste as described in claim 1.

4. A structure for a tremie pipe for loading soil and rock, comprising a tremie pipe and a hopper connected to the tremie pipe, wherein soil or rock debris is loaded into the tremie pipe from one end via the hopper and discharged from the other end of the tremie pipe, The tremie tube has a first portion on its side where the inside and outside of the tube are not in communication, and a second portion on its side which has an opening where the inside and outside of the tube are in communication. The tremie pipe is positioned in a predetermined body of water with one end near the water surface and the other end facing the bottom. The aforementioned end of the pipe is formed by the first portion, and the bottom-facing end of the first portion is at a depth of 2 meters or more. The second part is located closer to the seabed than the first part, The aforementioned openings are provided in a slit-like manner along the axial direction of the tremie tube at least at two locations in the circumferential direction, The width of the slit in the opening is at least 5 mm. Structure of a tremie pipe used for dumping soil, sand, and rock waste.

5. A structure for a tremie pipe for loading soil and rocks, comprising a tremie pipe and a hopper connected to the tremie pipe, wherein soil or rocks are loaded into the tremie pipe from one end via the hopper and discharged from the other end, The tremie tube has a first portion on its side where the inside and outside of the tube are not in communication, and a second portion on its side which has an opening where the inside and outside of the tube are in communication. The tremie pipe is positioned in a predetermined body of water with one end near the water surface and the other end facing the bottom. The aforementioned end of the pipe is formed by the first portion, and the bottom-facing end of the first portion is at a depth of 2 meters or more. The second part is located closer to the seabed than the first part, The aforementioned openings are provided in a slit-like manner along the axial direction of the tremie tube at least at two locations in the circumferential direction, The hopper has an inner slope that forms a V-shape in cross-section, An outlet is provided at the lower end of the inner slope, which communicates with the inside of the tremie pipe. The outlet is located underwater, The connection between the tremie pipe and the hopper is below the water level. Structure of a tremie pipe used for dumping soil, sand, and rock waste.

6. A structure for a tremie pipe for loading soil and rock, comprising a tremie pipe and a hopper connected to the tremie pipe, wherein soil or rock debris is loaded into the tremie pipe from one end via the hopper and discharged from the other end of the tremie pipe, The tremie tube has a first portion on its side where the inside and outside of the tube are not in communication, and a second portion on its side which has an opening where the inside and outside of the tube are in communication. The tremie pipe is positioned in a predetermined body of water with one end near the water surface and the other end facing the bottom. The aforementioned end of the pipe is formed by the first portion, and the bottom-facing end of the first portion is at a depth of 2 meters or more. The second part is located closer to the seabed than the first part, The aforementioned openings are provided in a slit-like manner along the axial direction of the tremie tube at least at two locations in the circumferential direction, The length of the underwater portion of the tremie tube is 50% to 90% of the water depth of the predetermined body of water. The other end of the tremie tube is composed of the second part, The other end of the pipe has a reinforcing portion on the outer circumferential surface of the second portion, Structure of a tremie pipe used for dumping soil, sand, and rock waste.

7. A method for constructing a structure, comprising using the structure of a tremie pipe for depositing soil and rock debris described in any one of claims 1 to 6 to deposit soil or rock debris into water to construct the structure.

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