JP2024011885A - Structure of tremie pipe for sediment/rock muck input, and structure construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: 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

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to the structure of a tremie pipe for charging soil and rock waste, and a method of constructing the structure.

Tremie pipes are sometimes used to inject earth and sand into predetermined locations on the seabed during construction work such as backfilling the remains of deep trenches in the seabed, reclamation in ports, submerged embankments, and shallow area creation. At that time, the tremie tube is placed underwater with the upper end above the water surface and the lower end facing the seabed, and earth and sand are introduced from the upper end via a hopper or the like. By using the tremie tube in this way, it is possible to suppress the occurrence of pollution in the sea and to be environmentally friendly. As such a tremie tube, there has been disclosed a tremie tube consisting of a double tube in which an outer tube having a larger diameter and length than the inner tube is arranged around an inner tube having an opening near the still water surface (patent patent). References 1-2). In addition, a tremie pipe in which a water intake port is provided below the water surface is also disclosed, even in a configuration other than a double pipe (Patent Document 3).

Japanese Patent Application Publication No. 2002-129568 Japanese Patent Application Publication No. 2002-129569 Utility Model Publication No. 5-10530

However, with the above-mentioned conventional technology, when the earth and sand etc. are thrown into the tremie pipe, pulsations occur in the water in the tremie pipe due to the impact of the earth and sand falling on the water surface and the falling inside the tremie pipe, and the water level in the tremie pipe is lowered. A large amount of turbidity tends to occur in the tremie tube as it moves up and down. Further, there is a problem in that a large amount of bubbles are generated in the water in the tremie pipe, and as the bubbles diffuse into the water, dirt is likely to spread to the surrounding area, causing water pollution. Regarding this bubble, a possible countermeasure is to arrange a screw conveyor, a water intake port, and a chamber with an air vent pipe in the tremie tube as in Patent Document 3, but this would require a large-scale device.

SUMMARY OF THE INVENTION Accordingly, one aspect of the present invention is a structure of a tremie pipe for introducing soil and rock debris into water with low viscosity, which is capable of suppressing the dispersion of soil and rock debris into the surrounding water area. The purpose of this study is to realize the structure of a tremie pipe for introducing sandstone waste and a construction method for the structure.

In order to solve the above problems, a structure of a tremie pipe for charging soil and rock waste according to one aspect of the present invention includes a tremie pipe and a hopper connected to the tremie pipe, and the earth and sand or rock waste is transferred to the hopper. The structure of the tremie pipe for charging soil and rock waste is introduced from one end of the tremie pipe and discharged from the other end of the tremie pipe, and the inside of the tremie pipe and the outside of the pipe communicate with each other on the side surface. the tremie tube has a first portion that is not connected to the outside of the tube, and a second portion that has an opening on the side surface through which the inside of the tube and the outside of the tube communicate, The other pipe end is arranged with the other end facing the water bottom, the one pipe end side is constituted by the first part, the end of the first part on the water bottom side is at a depth of 2 meters or more, and the second part is The opening is located closer to the bottom of the water than the first portion, and extends in the form of a slit along the tube axis at at least two locations in the circumferential direction of the tremie tube.

According to the above configuration, the first portion that does not have an opening that communicates the inside of the pipe with the outside of the pipe is provided at least up to a depth of 2 meters. Thereby, it is possible to prevent the earth and sand or rock debris immediately after being put into the water from undesirably spreading to the surrounding area near the water surface. That is, the first part plays the role of a conventional pollution prevention film or pollution prevention frame. Therefore, there is no need for a pollution prevention film, etc. that would be required when an opening is provided near the water surface, and without making the device large-scale, it suppresses pollution during input and removes low-viscosity soil and rock debris from the tremie pipe. can be led to the other tube end.

Further, according to the above configuration, the second portion located closer to the bottom of the water than the first portion has a slit-shaped opening. This allows water to flow into the pipe from the opening, and in conjunction with the flow of water into the pipe from the other end of the tremie pipe, promotes the fall of dirt or rock debris falling inside the pipe. , it is possible to suppress occlusion within the tube.

In the structure of the tremie pipe for introducing soil and rock waste according to one aspect of the present invention, in the above structure, 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 tube end side of the tube is constituted by the second portion.

According to the above configuration, the second part having the slit-shaped opening is provided on the bottom side of the water at a depth of at least 2 m, and this part allows water to flow into the pipe to prevent sediment or rock debris from falling. While promoting this, it is possible to suppress the occurrence of pulsation within the tube.

In the structure of the tremie pipe for introducing soil and rock waste according to one aspect of the present invention, in the above configuration, the width of the slit in the opening is at least 5 mm.

According to the above-mentioned configuration, the earth and sand and rock debris falling inside the tremie pipe are difficult to flow out of the pipe, and water from outside the pipe can be efficiently flowed into the pipe.

In the structure of the tremie pipe for charging soil and rock waste according to one aspect of the present invention, in the above structure, the hopper has an inner slope forming a V-shaped cross section, and the tremie pipe is attached to the lower end of the inner slope. An outlet communicating with the interior of the tube is provided, said outlet being located underwater.

According to the above configuration, the earth and sand or rock debris can be made to flow down on the hopper, slide into the water, and be introduced into the tremie pipe, so that there is no shock or pulsation when the earth and sand or rock debris falls on the water surface, and when the earth and sand or rock debris is thrown into the water. Entrainment of air can be suppressed.

In the structure of the tremie pipe for charging soil and rock waste according to one aspect of the present invention, in the above configuration, the connecting portion between the tremie pipe and the hopper is below the water surface.

According to the above configuration, the earth and sand or rock debris can be slid into the water on the hopper and thrown into the tremie pipe, so there is no impact or pulsation when the earth and sand or rock debris falls on the water surface, and air entrainment when the earth and sand or rock debris is thrown into the water. can be suppressed.

In the structure of the tremie pipe for charging soil and rock waste according to one aspect of the present invention, in the above configuration, a reinforcing portion is provided on the outer peripheral surface of the second portion of the other pipe end.

According to the above configuration, by having the reinforcing portion, deformation of the tremie tube can be prevented even if the other tube end is cut out by the opening.

In order to solve the above problems, a method for constructing a structure according to one aspect of the present invention is to construct a structure by injecting earth and sand or rock waste into water using the structure of the tremie pipe for introducing earth and rock waste having the above-described configuration. Build things.

According to the above method, by using a tremie tube having the structure of the tremie tube for introducing soil and rock debris as described above, it is possible to reduce the amount of sediment or rock debris in the water compared to charging with an open bottom purge or surface charging with a grab. It is possible to easily control the dropping position into the water (bottom of the water), and to properly drop earth and sand or rock debris into the water (bottom of the water) while suppressing pollution of the surrounding area at the time of dropping.

According to one aspect of the present invention, it is possible to suppress contamination during input and guide low-viscosity earth and sand and rock debris to the other end of the tremie tube without making the device large-scale.

FIG. 2 is a graph showing the difference in pollution generation intensity depending on the method of introducing earth and sand into water. FIG. 1 is a side view of the structure of a tremie pipe for introducing soil and rock waste according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of the second portion of the tremie tube shown in FIG. 2 taken along a direction perpendicular to the tube axis. FIG. 3 is a cross-sectional view of the second portion of the tremie tube shown in FIG. 2 taken along the tube axis direction, and is a cross-sectional view showing the shape of the opening. 3 is a diagram showing the structure of a hopper connected to the tremie pipe for charging soil and rock waste shown in FIG. 2, in which (a) is a plan view and (b) is a cross-sectional view taken along the cutting line AA' 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 sectional view taken along cutting line BB' in (d). FIG. 3 is a side view showing two different examples of the positional relationship between the hopper provided in the structure and the water surface in the structure of the tremie pipe for introducing soil and rock waste shown in FIG. 2; FIG. 3 is a diagram illustrating the configuration of a hopper included in the tremie pipe for introducing soil and rock waste shown in FIG. 2; It is a figure explaining the construction method of the structure using the structure of the tremie pipe for introducing earth and rock waste shown in FIG. It is a figure explaining the modification of the construction method of the structure using the structure of the tremie pipe for introducing earth and rock waste shown in FIG. It is a side view of the structure of the tremie pipe for introducing earth and rock waste according to another embodiment of the present invention.

[Embodiment 1]
In recent years, earth and sand input methods that have been adopted in port construction include earth carrier loading, grab loading, and tremie loading. Comparing the pollution generation intensity of each input method in the graph shown in Figure 1, it can be seen that the generation of turbidity in the water is more remarkable compared to other input methods since soil transport input is directly input into a designated water area. Recognize. On the other hand, with grab loading, the grab is lowered into the water and soil is deposited near the bottom of the water, which is expected to have the effect of suppressing pollution, but it has the problem of low work efficiency. Compared to these feeding methods, tremie feeding, in which a tremie tube is installed at the target feeding position on the bottom of the water and the earth and sand falls inside the tube, can achieve efficient feeding with less pollution. By the way, as an example of tremie injection, there is a method of flowing water from the outside in order to prevent blockage in the pipe, and the present inventors have conducted research and development of a tremie pipe in which an opening is provided in the pipe body to allow water to flow in. It is carried out. Therefore, the present inventors have discovered a structure of a tremie pipe that enables efficient tremie input of low-viscosity earth and sand or rock debris and suppresses the occurrence of pollution, and has completed one aspect of the present invention. It's arrived. Hereinafter, one embodiment of the present invention will be described using the drawings.

(Structure of tremie pipe for charging soil and rock waste)
FIG. 2 is a side view of the structure of the tremie pipe for introducing soil and rock waste in one embodiment of the present invention. A structure 1 of a tremie pipe for charging soil and rock waste includes a tremie pipe 10 and a hopper 20 connected to the tremie pipe 10. In the structure 1 of the tremie tube for introducing earth and rock waste, earth and sand or rock waste is introduced into the tremie pipe 10 from one end 12 of the tremie pipe 10 via the hopper 20 and discharged from the other end 14 of the tremie pipe.

(tremie tube 10)
The tremie pipe 10 is arranged in a predetermined water area with one pipe end 12 near the water surface and the other pipe end 14 facing the water bottom WG when introducing earth and sand and rock debris. When placed in a predetermined water area, the axial direction of the tremie tube 10 is substantially parallel to the vertical direction. Below, the specific configuration of the tremie tube 10 and the positional relationship between the configurations will be explained based on the tremie tube 10 placed in a predetermined water body in this way.

The tremie tube 10 has a first portion 10A in which the inside of the tube and the outside of the tube do not communicate on the side surface, and a second portion 10B that has an opening 16 on the side surface where the inside of the tube and the outside of the tube communicate with each other. The tremie tube 10 includes a first portion 10A on one tube end 12 side.

In other words, the first portion 10A is a portion in which no opening is provided on the circumferential surface (side surface) of the tube. The opening here refers to the inflow of water from the outside of the pipe into the pipe from the circumferential surface of the pipe, regardless of whether it has the same shape as the opening 16 provided in the second portion 10B. This is an opening that allows water to flow from the inside to the outside of the pipe.

The end of the first portion 10A on the water bottom side (the boundary portion between the first portion 10A and the second portion 10B) is located at a depth of 2 meters or more. The water depth of 2 meters or more means that the bottom side end of the first portion 10A may be located at a water depth of more than 2 meters. In short, this means that the tremie tube 10 does not have an opening in the range from the water surface to a depth of at least 2 meters.

Here, one tube end 12 of the tremie tube 10 may be located at the same position as the water surface or below the water surface, but it is more desirable that it be located below the water surface. Below the water surface is the range from the water surface to a depth of 1 meter. When one tube end 12 is located at approximately the same position as the water surface, the length of the first portion 10A in the tube axis direction is at least 2 meters deep from the water surface. As another example, when one tube end 12 is below the water surface, the range from the one tube end 12 to a depth of 2 meters may be at least the first portion 10A.

In yet another example, if the configuration of one tube end 12 of the tremie tube 10 is such that the lower end of the hopper 20 can be communicated underwater, the one tube end 12 itself may not be connected near the water surface. It may be located above the water surface. For example, there may be a configuration in which a notch is provided at one end 12 of the tremie tube 10 toward the bottom of the water, and a hopper is fitted into the notch. In this case, the water surface is located at a position slightly below one of the pipe ends 12, and the first portion 10A is configured to have no opening at a depth of at least 2 meters from this water surface position.

The second portion 10B is located closer to the water bottom WG than the first portion 10A, and as shown in FIG. 2, is located on the other tube end 14 side. Specifically, the other tube end 14 side of the tremie tube 10 may be constituted by the second portion 10B.

The opening 16 provided in the second portion 10B extends in the shape of a slit along the tube axis direction. The slit-shaped openings 16 are provided at least at two locations in the circumferential direction of the tremie tube 10. FIG. 3 is a cross-sectional view of the second portion 10B taken in a direction perpendicular to the tube axis. For example, the slit-shaped openings 16 are provided at four locations in the circumferential direction of the tremie tube 10, as shown in FIG. It should be noted that the plurality of slit-shaped openings 16 do not need to be provided at equal intervals along the circumferential direction of the tremie tube 10, and are biased in the circumferential direction (for example, in FIG. (only the portion 16 is provided) may also be provided. As an example, there is a mode in which the tremie tube 10 is not provided on the side facing the water flow, taking into consideration the water flow of a predetermined water area in which the tremie tube 10 is arranged. With this aspect, even if the water flow passes through the inside of the tremie tube 10, it is possible to suppress the occurrence of contamination.

The slit-shaped opening 16 has a width (length along the circumferential direction of the tremie tube 10) of at least 5 mm. By having a width of at least 5 mm, it is possible to improve the inflow and outflow of water between the outside of the tube and the inside of the tube. Moreover, it is preferable that the width is 20 mm or less. By being 20 mm or less, it is possible to suppress the outflow of earth and sand or rock debris flowing down the tremie pipe 10 to the outside of the pipe.

Since the slit-shaped opening 16 extends along the pipe axis direction, it is possible to suppress the dispersion of earth and sand or rock debris flowing down inside the pipe. If the longitudinal direction (extension direction) of the opening is inclined or perpendicular to the pipe axis, the direction of flow of earth and sand or rock debris will intersect with the edge of the slit-shaped opening. This is because the flowing earth and sand or rock debris is dispersed in the flow direction within the pipe by coming into contact with the edges.

A preferred aspect of the edge of the slit-shaped opening 16 will be described below with reference to FIG. 4. FIG. 4 is a partial cross-sectional view of the tremie tube 10, and is a cross-sectional view at a position where the slit-shaped opening 16 is provided. As shown in FIG. 4, the lower end of the slit-shaped opening 16 is provided with an inclined surface 16a that is inclined upward toward the outside of the tube. 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. FIG. 4 shows a mass of earth and sand or rock debris 500 flowing down inside the pipe. Since the slit-shaped opening 16 is provided with the inclined surface 16a, the inward angle of the tube 10 is an obtuse angle. Thereby, compared to the case where the corner is an acute angle, it is possible to suppress the decomposition of the lump when the lump comes into contact with the corner of the edge, and to suppress the dispersion of earth and sand or rock debris.

The length of the second portion 10B in the tube axis direction is not particularly limited, and the second portion 10B may be configured in the length of the underwater portion of the tremie tube 10 excluding the length of the first portion 10A. Preferably, the axial length of the tube is at least 2 meters.

The length of the underwater portion of the tremie tube 10 is 50% to 90% of the water depth of the predetermined water area in which the tremie tube is placed. Thereby, earth and sand or rock debris can be effectively thrown into the dropping target position. The diameter of the tremie tube 10 may be 300 mm or more and 2500 mm or less, but is not limited thereto. According to this embodiment, it is possible to suppress the dispersion of earth and sand or rock debris and to efficiently input the soil or rock debris. Therefore, the diameter of the tremie tube 10 can be made relatively large, for example, about 2000 mm, and it is possible to realize an embodiment in which a large amount of earth and sand or rock debris can be injected at one time.

(Hopper 20)
The hopper 20 shown in FIG. 2 has an inner slope 26 forming a V-shaped cross section. The connecting portion between the tremie tube 10 and the hopper is below the water surface WS. That is, the connecting part is underwater. In short, the outlet 22, which is provided at the lower end of the inner slope 26 and communicates with the inside of the tremie tube 10, is located underwater.

The hopper 20 will be explained using FIG. 5. FIG. 5(a) is a plan view of the hopper 20. The hopper 20 is provided with an outlet 22 that communicates with one tube end 12 of the tremie tube 10. The outlet 22 is provided at a corner of the hopper 20 in plan view. Further, in the hopper 20, the flow path leading to the outlet 22 starts from a position diagonal to the outlet 22 in plan view and is inclined downward toward the outlet 22. Specifically, the hopper 20 has a valley shape (V-shaped valley, trapezoidal shape, or U-shaped valley), and includes a slope 26a on one side of the slope 24 corresponding to the bottom of the valley; The outlet 22 has a slope 26b on the other side, and the outlet 22 is located at one end of the slope 24. Therefore, the flow path up to the outlet 22 is configured to start from near the end on the zenith side of the inclined surfaces 26a, 26b facing the valley. Note that one tube end 12 of the tremie tube 10 is disposed directly below the outlet 22 and communicates with it. By configuring the hopper 20 in this way, the earth and sand or rock debris dropped from a belt conveyor etc. flows down the flow path from the position where it is dropped into the hopper 20 to the outlet 22, and is directly thrown into the water surface. This has the advantage of suppressing pulsation and preventing contamination. Here, in the hopper 20, the ramp 24 is also inclined with respect to the horizontal plane, and the outlet 22 is located below the ramp 24. The angle of inclination of the ramp 24 with respect to the horizontal plane may be smaller or larger than the angle of inclination of the inclined surfaces 26a, 26b with respect to the horizontal plane. When the slope angle of the slope 24 with respect to the horizontal plane is smaller, the earth and sand or rock debris that has flowed down the slope 26a or 26b to the slope 24 flows to the outlet 22 while being stored in the slope 24.

Note that FIG. 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′ attached to the hopper 20 in FIG. 5(a). The slope 24 corresponding to the bottom of the valley may have a V-shape in which the slope 26a and the slope 26b intersect in cross-sectional view. Alternatively, as shown in FIG. 5(c), in a cross-sectional view, the portion where the inclined surfaces 26a and 26b intersect may be curved to have a U-shape. In this specification, the hopper 20 having the V-shaped ramp 24 is referred to as a hopper having an inner slope forming a V-shaped cross section. Note that the shape in which the intersecting portions are curved and has a U-shape also has a flat shape between the sloped surface 26a and the sloped surface 26b, as shown in the plan view of the modified example of the hopper 20 shown in FIG. 5(d). In other words, even if the bottom of the valley is flat as shown in FIG. 5(e) (cross-sectional view taken along line BB' in FIG. 5(d)), it can be said that it is approximately V-shaped. In this document, it is included in a hopper with an inner slope forming a V-shaped cross section.

Since the outlet 22 of the hopper 20 is located underwater as shown in FIG. 2, the hopper 20 can slide earth and sand or rock debris diagonally into the water, and in particular, the slopes 26a and 26b are submerged. When the soil or rock debris is flowing down the slopes 26a and 26b, the air between the soil and rock debris is discharged into the water, so that when the soil or rock debris falls to the water surface, the air is discharged into the water. Entrainment of air can be suppressed.

(Effects achieved by this embodiment)
The effects of the structure 1 of the tremie pipe for introducing soil and rock waste according to the present embodiment will be described with reference to FIG. 6. FIG. 6(a) shows a state in which one end 12 of the tremie tube 10 is at approximately the same position as the water surface, and FIG. 6(b) shows a state in which one end 12 of the tremie tube 10 is below the water surface. The figure shows an aspect in which the slopes 26a and 26b are partially submerged in water. Both aspects of FIGS. 6A and 6B are within the scope of this embodiment. The structure 1 of the tremie pipe for introducing soil and rock waste in the embodiments (a) and (b) of FIG. 6 is such that, as shown in FIG. The bottom side (second portion 10B side) end of the first portion 10A configured on the 12 side is provided at a depth of 2 meters or more. Thereby, it is possible to prevent the earth and sand or rock debris 500 immediately after flowing down the hopper 20 and being thrown into the water from undesirably spreading to the surroundings near the water surface WS. Therefore, the pollution prevention membrane and pollution prevention frame that were previously required are no longer necessary, and it is possible to suppress pollution and allow soil or rock debris to flow down to the other end 14 of the tremie pipe, without making the device large-scale. can. Furthermore, by providing a slit-shaped opening 16 in the second portion 10B, water can flow into the tremie tube 10 from the opening 16, and water can flow into the tube from the other tube end 14. In conjunction with the inflow and outflow of water, it is possible to promote the fall of earth and sand or rock debris that falls within the pipe, and to suppress blockage within the pipe. In addition, since the earth and sand or rock debris 500 is fed into the tremie pipe 10 via the hopper 20, the impact of falling onto the water surface or the influence of pulsation as it flows down the inside of the tremie pipe 10 is suppressed, and the impact of the earth and rock debris 500 is suppressed. Difficult to disperse sludge. In particular, compared to the embodiment shown in FIG. 6(a), the embodiment shown in FIG. 6(b) in which the outlet 22 of the hopper 20 is located underwater is more likely to prevent air from being drawn in from earth and sand or rock debris as described above. In addition, it is possible to suppress the dispersion of earth and sand or rock debris 500.

Here, the effects of the structure 1 of the tremie pipe for introducing soil and rock waste according to the present embodiment will be explained in comparison with a tremie pipe structure of a comparative configuration. FIG. 7 illustrates four types of tremie tube structures, and from the left side of the drawing, (a) first comparative structure 1001, (b) second comparative structure 1002, and (c) third comparative structure 1003 are comparative structures. , (d) at the right end of the drawing is the structure 1 of the tremie pipe for introducing earth and rock waste according to the present embodiment. For comparison, both structures have the same pipe diameter and have a hopper connected to the upper end of the tremie pipe.

In the first comparative structure 1001 in FIG. 7A, the tremie tube 1011 is not provided with an opening over the entire length of the tube. When earth and sand or rock debris 500 is thrown into the first comparison structure 1001 having such a configuration, it falls directly onto the water surface, causing large pulsations and fluctuations in the water surface as shown by arrows, and often causing pollution. Further, since no opening is provided, water can only flow into the tremie tube 1011 from the lower end of the tremie tube 1011. As a result, water movement in the pipe near the lower end of the tremie pipe 1011 increases in conjunction with outflow of water inside the pipe due to discharge of the earth and sand or rock debris 500, causing dispersion and pollution of the earth and sand or rock debris 500. Easy to do.

The second comparative structure 1002 in FIG. 7(b) is a tremie tube 1012 that is not provided with an opening like the first comparative structure 1001, and the tube length itself is short. When earth and sand or rock debris 500 was put into the second comparative structure 1002, it was quickly discharged from the lower pipe end of the tremie pipe 1012, although the pulsation and water level fluctuation were smaller than in the first comparative structure 1001 due to the short pipe length. Fine particles of earth and sand or rock debris 500 are dispersed in the water, and the water flow spreads the pollution over a wide area.

In the third comparative structure 1003 in FIG. 7(c), a slit-shaped opening 1063 is provided along the tube axis direction over almost the entire length of the tremie tube 1013. When earth and sand or rock debris 500 is put into the third comparative structure 1003 having such a configuration, water flows in and out through the opening 1063 near the water surface, unlike clayey soil because earth and sand or rock debris has low viscosity. The generation of contamination and the diffusion of contamination outside the tremie tube 1013 occur. Therefore, when adopting the third comparison structure 1003, it is necessary to install a pollution prevention film or a pollution prevention frame at least on the water surface and below the water surface. Furthermore, since the opening 1063 is present over almost the entire length of the tremie tube 1013, although pulsation and fluctuations in the water level are small, contaminants are diffused outside the tube over the entire length.

In the structure 1 of the tremie pipe for introducing soil and rock waste according to the present embodiment shown in FIG. The generation of pollution is suppressed and there is no diffusion outside the area. In addition, in the structure 1 of the tremie pipe for introducing soil and rock waste according to the present embodiment, the second portion 10B is provided with the slit-shaped opening 16, so that there is no flow between the inside of the pipe and the outside of the pipe through the opening 16. By realizing water inflow and outflow, it is possible to promote the flow of earth and sand or rock debris 500.

In addition, in this embodiment, although the one pipe end 12 to the other pipe end 14 is comprised of one straight pipe, the present invention is not limited to this, and the straight pipe corresponding to the first portion 10A, The straight pipe corresponding to the second portion 10B may be connected by a well-known connection structure. In the embodiment in which a plurality of straight pipes are connected in this manner, the connection position may be located in the middle of the length of the first portion 10A in the pipe axial direction, or may be located midway in the length of the second portion 10B in the pipe axial direction. good.

FIG. 8 shows a diagram illustrating a method of constructing a structure using the structure 1 of the tremie pipe for introducing soil and rock waste according to the present embodiment. FIG. 8(a) is a diagram explaining the construction state, and FIG. 8(b) is a step diagram of construction. The construction method includes the steps of installing the tremie pipe 10 for charging soil and rock waste in a predetermined water area (S1 in FIG. 8(b)), and placing the soil into a hopper 20 connected to the installed tremie pipe 10 for charging soil and rock waste. Alternatively, it includes a step of throwing in rock debris (S2 in FIG. 8(b)). The installation in step S1 includes measuring the water depth at the placement position and setting the axial length (underwater portion) of the tremie tube 10 based on the measured water depth, and the position relative to the water surface is determined by a well-known support mechanism. It is sufficient that the tremie pipe 10 or the structure 1 of the tremie pipe for introducing soil and rock waste is supported so as to be in a predetermined position. Regarding the charging in step S2, earth and sand or rock debris is dropped onto the inner slope 26 (slanted surface) of the hopper 20 using a belt conveyor 100 or the like.

In addition, as the above-mentioned belt conveyor 100, the conveyor of a reclaimer ship or a falling mixing ship can be mentioned. Note that the earth and sand or rock debris may be introduced into the hopper 20 not only by a belt conveyor but also by a grab or a bucket of a backhoe. Furthermore, as shown in FIG. 8A, the belt conveyor 100 is preferably installed so that the falling earth and sand and rock debris 500 fall approximately in the middle of the ramp 24 of the hopper 20.

(Modified example)
FIG. 9 shows a flow of a modification of the construction method. This modification includes a step (S2a in FIG. 9) of pre-treating the earth and sand or rock debris before the step of charging the soil and rock debris into the structure 1 of the tremie pipe (FIG. 8(b) S2).

In step S2a of FIG. 9, as a pretreatment step, earth and sand or rock debris is placed in a water tank or the like in advance to measure turbidity, etc., and pretreatment is performed when the amount of pollution generated is large. Pretreatment is the spraying or addition and mixing of an anti-segregation agent to prevent the dispersion of earth and sand or rock debris. The anti-segregation agent can be sprayed onto the earth and sand or rock debris on the belt conveyor 100 in FIG. As the separation preventing agent, a separation preventing agent containing a water-soluble polymer such as a well-known acrylic type or cellulose type can be used.

In addition, when performing the pretreatment step S2a with a backhoe, it is necessary to perform the pretreatment step S2a on a quay, etc., before or in parallel with the work in step S1 of installing the tremie pipe 10 for introducing soil and rock waste into a predetermined water area. A modification of FIG. 9 also includes a configuration in which the mixing operation is performed at another location, and step S2 is performed in which the rock waste, etc. subjected to the pretreatment step S2a is moved to a storage place for charging into the tremie tube 10, and step S2 is performed. regarded as.

(soil and rock debris)
The object for which the structure 1 of the tremie pipe for introducing earth and rock waste according to the present embodiment is used is earth and sand or rock waste, and these have low viscosity and do not easily form into clods. Therefore, when placed in water, they are clumped together to some extent in the form of a lump, but water can pass through the inside of the lump. Here, the rock debris is a residue from the production of stone, and there is no particular restriction on the size, but it is desirable that the maximum particle size is 300 mm.

As mentioned above, the structure 1 of the tremie pipe for introducing soil and rock debris was explained to be used exclusively for soil and rock debris. The injection can be performed using Structure 1 of the injection tremie tube.

[Embodiment 2]
Other embodiments of the invention will be described below. For convenience of explanation, members having the same functions as the members described in the above embodiment are given the same reference numerals, and the description thereof will not be repeated.

FIG. 10 is a side view of the structure 2 of the tremie pipe for introducing soil and rock waste according to the present embodiment. The structure 2 of the tremie pipe for introducing soil and rock waste according to the present embodiment extends to the other pipe end 14 of the tremie pipe 10, and has a slit-shaped opening 16 provided as if the other pipe end 14 is cut out. This differs from the structure 1 of the tremie pipe for introducing earth and rock waste according to the first embodiment in that a reinforcing portion 30 is provided on the outer peripheral surface of the second portion 10B so that the other pipe end 14 is not deformed. Note that a plurality of reinforcing portions 30 may be provided at a predetermined distance in the tube axis direction depending on the length of the second portion 10B of the tremie tube, and may be provided at least near the other tube end 14. Good too.

The structure 2 of the tremie pipe for introducing earth and rock waste according to the present embodiment also provides the same effects as the structure 1 of the tremie pipe for introducing earth and rock waste according to the first embodiment. Note that the slit-shaped opening 16 may not extend to the other tube end 14, and the tube body of the tremie tube 10 may be located around the entire circumference of the other tube end 14.

In addition, according to the structure 1 and 2 of the tremie pipe for introducing earth and rock waste explained in Embodiment 1 and Embodiment 2, generation of pollution into water can be suppressed. Such effects also contribute to the achievement of, for example, Goal 14 of the Sustainable Development Goals (SDGs) advocated by the United Nations, ``Let's protect the richness of our oceans.''

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

1, 2 Structure of tremie pipe for charging soil and rock waste 10 Tremie pipe 10A First part 10B Second part 12 One pipe end 14 Other pipe end 16 Opening 20 Hopper 22 Outlet 24 Slope 26, 26a, 26b Slope (inner slope)
30 Reinforcement part 100 Belt conveyor 500 Earth and sand or rock debris

Claims (7)

A method for introducing soil and rock waste, comprising a tremie pipe and a hopper connected to the tremie pipe, in which earth and sand or rock waste is introduced from one end of the tremie pipe through the hopper and discharged from the other end. The structure of a tremie tube for
The tremie tube has a first portion where the inside of the tube and the outside of the tube do not communicate on a side surface, and a second portion having an opening where the inside of the tube and the outside of the tube communicate with each other on the side surface,
The tremie tube is arranged with the one tube end near the water surface and the other tube end facing the water bottom in a predetermined water body,
The one pipe end side is constituted by the first part, and the bottom side end of the first part is at a depth of 2 meters or more,
The second portion is located closer to the bottom of the water than the first portion,
The openings extend in a slit shape along the tube axis direction at at least two locations in the circumferential direction of the tremie tube.
Structure of a tremie pipe for introducing soil and rock waste. The length of the underwater portion of the tremie tube is 50% to 90% of the water depth of the predetermined water area,
the other tube end side of the tremie tube is constituted by the second portion;
The structure of the tremie pipe for introducing soil and rock waste according to claim 1. The width of the slit in the opening is at least 5 mm.
The structure of the tremie pipe for introducing soil and rock waste according to claim 1. The hopper has an inner slope forming a V-shaped cross section,
An outlet communicating with the inside of the tremie tube is provided at the lower end of the inner slope,
the outlet is located underwater;
The structure of the tremie pipe for introducing soil and rock waste according to claim 1. a connecting portion between the tremie tube and the hopper is below the water surface;
The structure of the tremie pipe for introducing soil and rock waste according to claim 4. having a reinforcing portion on the outer circumferential surface of the second portion of the other tube end;
The structure of the tremie pipe for introducing soil and rock waste according to claim 2. A method for constructing a structure, comprising constructing a structure by introducing earth and sand or rock waste into water using the structure of the tremie pipe for introducing earth and rock waste according to any one of claims 1 to 6.

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