JP3310660B2 - Bottom material improvement device and bottom material improvement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for improving sediment, and more particularly to an apparatus and method for improving sediment in which volcanic ash or the like is deposited on sandy ground. About.

[0002]

2. Description of the Related Art A prior art as the background of the present invention is disclosed in Japanese Patent Publication No. Hei 3-8737. According to this prior art, the sedimented oyster shell is crushed into small pieces in water by high-pressure jet water, and the small pieces, the mud under the oyster shell, and the water on the oyster shell are mixed and stirred. The method is characterized in that the pieces are settled by their own weight and the mud is deposited on the strips.

[0003]

However, in this conventional apparatus for improving the quality of sediment, although the enclosure is surrounded by the cage, only the upper surface of the cage is covered with the wire mesh, so that the apparatus is substantially opened. The mud and the oyster shells were mixed and stirred in the region where the oyster shells were mixed. Therefore, when the sediment is relatively light, such as volcanic ash, the mixture may flow out and diffuse into the construction sea area from a cage whose ceiling is completely open, and the surrounding sea area may become turbid for a long time. Further, if the mixing and stirring of the volcanic ash and the sand and mud are not performed in a substantially closed state, the volcanic ash flows out and diffuses into the surrounding sea area, so that there is a problem that the stirring efficiency is poor.

[0004] Therefore, a main object of the present invention is to provide a bottom quality improving apparatus and a bottom quality improving method which are less likely to pollute the surrounding sea area during construction and have a high construction efficiency.

[0005]

According to a first aspect of the present invention, there is provided a bottom sediment improving apparatus according to the present invention, wherein a cage is provided to surround a construction area, and is driven by a motor held inside the cage. A rotating shaft, a high-pressure water jet nozzle for injecting high-pressure water toward the sediment while changing the spray direction with the rotation of the rotating shaft, and a sediment blown up by the high-pressure water as the rotating shaft rotates. A sediment improving device including a stirring blade for stirring, wherein a partition is provided in a cage to vertically separate a depth direction of the cage, and high-pressure water is jetted into a region surrounded by the cage, the partition, and a water bottom. This is a bottom quality improvement device in which a nozzle and a stirring blade are arranged.

According to a second aspect of the present invention, there is provided a bottom sediment improving apparatus according to the first aspect of the present invention, wherein the rotating shaft is used in a state of being substantially upright with respect to the water bottom. The high pressure water is sprayed at an oblique angle with respect to the water bottom.

According to a third aspect of the present invention, there is provided a bottom sediment improving apparatus according to the first or second aspect of the present invention, wherein the tip end portion of the stirring blade and the inner wall of the cage are provided. It is characterized by a gap of at least greater than the diameter of the volcano rake. The bottom sediment improvement device of the present invention according to claim 3 is preferable in that the bottom sediment near the volcano is improved.

Further, the method for improving sediment quality according to the present invention according to the present invention is characterized in that the upper part and the periphery of the sediment and the sediment on the water bottom are surrounded in a substantially closed state, and are stirred by a stirring blade while being blown off with high-pressure water. A method for improving sediment, comprising stirring and mixing water, sand and mud, and sediment, and then allowing the mixture to settle.

According to a fifth aspect of the present invention, there is provided a method for improving sediment according to the present invention, comprising lowering a cage having a sealed region capable of applying pressure by its own weight and having a substantially sealable area to a sediment on which sediment is deposited. The process, a cultivation process that crushes and plows the sediment while injecting and blowing high-pressure water onto the sediment, and agitating and mixing the sediment and sediment crushed and cultivated in the cultivation process with stirring blades And a sedimentation step of sedimenting the agitated mixture of sediment and sediment by consolidating the closed area of the cage.

Further, the method of improving sediment of the present invention according to claim 6 is capable of applying pressure by its own weight to the sediment on which a deposit composed of a volcanic ash layer including volcanic ash and volcanic debris can be applied and can be substantially sealed. Cultivating and cultivating the sediment by crushing and cultivating the sediment by the process of lowering the cage having a tightly closed area, the injection of high-pressure water by the high-pressure water jet nozzle against the sediment, and the rotation of the stirring blades. A stirring step of stirring the cultivated sediment and sediment with a stirring blade, and a sedimentation step of sedimenting a stirred mixture of sediment and sediment by consolidation of the closed area of the cage, wherein the sealed area is a cage. Is formed in a substantially closed state by an area surrounded by a partition partitioning a depth direction of the cage up and down, an inner wall of the cage, and the water bottom when the bottom of the cage is settled on a water bottom. This is an improved method.

Further, a method of improving sediment according to the present invention according to claim 7 is a method of improving sediment according to the invention according to claim 5 or 6, wherein a cage is attached to a predetermined construction area of the sediment. It is characterized by including a positioning step for bottoming and positioning.

[0012]

In the apparatus for improving sediment quality according to the present invention, a partition is provided in the cage to vertically separate the depth direction of the cage, and a high-pressure water jet nozzle and a stirring blade are provided in an area surrounded by the cage, the partition and the water bottom. Is arranged. During the construction of the sediment improvement method, the high-pressure water injected from the high-pressure water injection nozzle blows up the sediment, and the blown-up sediment is mixed with stirring blades, but the construction area is surrounded by cages. , The upper part is surrounded by a partition wall, so that the sediment mixture hardly leaks into the surrounding sea area. In addition, since the surrounding area and the upper part of the construction area are covered with the cage and the partition wall, pressure is applied to the construction area by the weight of the apparatus, so that the mixing and stirring can be performed while increasing the density of the stirring mixture, and the efficiency of the mixing and stirring can be increased. .

In the closed area of the cage, the sediment on the sediment is blown up by jetting of high-pressure water by a high-pressure water jet nozzle or the like, and the base layer of the sediment is crushed and plowed. Change to a loose state. Furthermore, since the partition wall surface in the closed area of the cage has a baffle effect together with the application of pressure due to the weight of the cage, the sediment blown up by the swirling flow hits the partition wall surface, flows downward, and goes upstream and downstream. In this case, in the enclosed area of the cage, the sediment such as a volcanic ash layer deposited on the sediment and the sediment located An upside down phenomenon occurs with the upper layer of the base layer. That is, since a mixed layer is formed on the water bottom where a volcanic ash layer including, for example, volcanic ash and volcanic debris and an upper layer of sediment including sand and mud are formed, and the volcanic ash layer covers the entire water bottom. The sediment quality is improved compared to the case where

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention with reference to the accompanying drawings.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a perspective view showing an example of an apparatus for improving sediment quality according to the present invention, and FIG. 2 is a bottom view thereof. FIG. 3 is a schematic cross-sectional view of the sediment improving apparatus shown in FIG. FIG.
The bottom quality improving device 10 shown in FIG. 1 is formed by connecting three units 12. Each unit 12 of this embodiment
Is provided with two stirring blades 14, and the apparatus as a whole is provided with a total of six stirring blades 14.

Each unit 12 will be further described with reference to FIG. Unit 12 of the bottom quality improvement device 10
Includes a cage 16 in the form of a square tube. The cage 16 is for holding each member to be described later and surrounding the construction area. A prime mover 18 is installed on the wire mesh ceiling of the cage 16. One end of, for example, a pipe-shaped rotating shaft 20 is connected to the prime mover 18 by being vertically suspended. The rotating shaft 20 is rotated about its central axis by the motor 18. An intermediate portion of the rotating shaft 20 is rotatably held by a bearing 22. The bearing 22 is fixed to the inner wall of the cage 16 via the crosspiece 24.

A stirring blade unit is connected to the lower end of the rotating shaft 20. The stirring blade 14 is provided to protrude around the lower end of the rotating shaft 20 in a direction substantially orthogonal to the central axis of the rotating shaft 20. The rotating shaft 20 has, for example, three blades, and the tips of the blades are surrounded by an annular member 26. The edge of the annular member 26 facing the water bottom is processed in a zigzag shape. In addition, a space larger than the diameter of the volcano rake is provided between the annular member 26 fixed to the tip of the stirring blade 14 and the inner wall of the cage 16. This allows
When improving the sediment quality of the water bottom on which volcanic ash and volcanic rake near the volcano are deposited, the volcanic rake is not interposed between the tip of the stirring blade 14 and the cage 16 and does not hinder the rotation of the stirring blade 14. In this embodiment, a space of 20 cm or more is provided between the stirring blades 14 and between the stirring blades 14 and the cage 16.

A high-pressure water jet nozzle 28 is provided on the side wall of the stirring blade unit. The high-pressure water jet nozzle 28 jets high-pressure seawater toward the bottom of the water bottom while changing the jet direction of the high-pressure water by 360 ° with the rotation of the rotating shaft 20. In this embodiment, the high-pressure water jet nozzle 28 is provided so that high-pressure seawater is jetted obliquely downward, for example, at approximately 45 ° from the center axis of the rotating shaft 20. The supply of high-pressure seawater to the high-pressure water jet nozzle 28
This is performed by a supply pipe provided in the rotating shaft 20.
The angle of the high-pressure water jet nozzle 28 can be appropriately selected to achieve the object of the present invention.

A spear-shaped projection 32 is provided at the lower end of the stirring blade unit. The protruding portion 32 pierces the sediment of the water bottom and is used for positioning the sediment improving device 10 during construction.

A rectangular partition wall 30 is provided horizontally in the middle of the cage 16 in the depth direction to vertically separate the depth direction.
The peripheral edge of the partition 30 is fixed to the inner wall of the cage 16 by, for example, welding. Rotating shaft 20 penetrating partition 30 and partition 3
An annular gap 30 a is provided between the gap 30. The gap 30 a is provided so as not to hinder the rotation of the rotating shaft 20 and to allow water and air to flow in the thickness direction of the partition 30. If the gap 30a is too large, the sediment mixed and mixed at the time of construction leaks out and pollutes the surrounding sea area.
The size of the gap 30a is minimized. Gap 30a
The water and air circulated through the wire mesh ceiling of the cage 16,
In addition, the fluid flows out of the cage 16 through the through hole 16 a provided in the side wall of the cage 16.

Next, a method for improving the bottom quality of the seabed using the bottom quality improving apparatus 10 will be described with reference to FIGS. The bottom quality improving device 10 is suitable for improving the bottom quality in which a volcanic ash layer is laminated on a sandy soil layer, for example. First, the sediment improvement apparatus 10 is transported to the construction water area by the work fleet, and is immersed in the water while being hung by the hoist ship as shown in FIGS. 4, 5, and 6. The working fleet is composed of, for example, a hoisting boat, a tugboat, and a yang anchor boat.

Next, the sediment improving apparatus 10 is settled on the upper surface of the sediment while rotating the rotating shaft 20 to eject high-pressure water from the high-pressure water jet nozzle 28. Then, the high-pressure water blows up volcanic ash and volcanic rake in the upper sediment, and the stirring blade 1
4 with stirring. Further, the sediment improving apparatus 10 sinks into the volcanic ash layer by its own weight (5 tons) until the spear-shaped projection 32 penetrates the sandy soil layer. As the sediment improving apparatus 10 sinks into the sediment, sand and mud is blown up by high-pressure water, and mixed and agitated with the volcanic ash by the stirring blades 14. The jetting of the high-pressure water and the mixing by the stirring blades 14 are performed for a predetermined time in a state of sinking to a predetermined depth. At this time, the construction area is substantially enclosed by being surrounded by the cage 16 and the upper part by the partition 30 so that the surrounding sea area is not polluted during construction. In addition, since pressure due to the weight of the sediment improving apparatus 10 is applied to the area sealed by the cage 16 and the partition 30, the mixing and stirring can be performed efficiently. In addition, the bottom sediment mixture slightly flows out of the gap 30a, but is slightly smaller than that of the conventional apparatus.

After a predetermined working time has elapsed, the injection of high-pressure water and the stirring are stopped, the sediment improving apparatus 10 is withdrawn, moved to the adjacent sediment improving area, and the same sediment improving operation as described above is repeatedly performed. Will be Thus, the sediment improving apparatus 10
The area constructed by the method is settled in a state where sand mud and volcanic ash are mixed, so that the sediment is improved compared to a state where the water bottom is entirely covered with only volcanic ash.

As described above, in the sediment improving apparatus 10, the partition wall 30 that vertically separates the depth direction of the cage is provided in the cage 16, and the high-pressure water is provided in the area surrounded by the cage, the partition wall, and the water bottom. The ejection nozzle 28 and the stirring blade 14 are arranged. When constructing the bottom quality improvement method, use the high pressure water injection nozzle 2
The high-pressure water injected from 8 blows up the sediment, and the blown-up sediment is mixed by the stirring blades 14. However, since the periphery of the construction area is surrounded by the cage 16, and the upper part of the construction area is surrounded by the partition 30, Almost no sediment mixture leaks into the surrounding sea area. Also, the cage 16 is located around and above the construction area.
In addition, by being covered with the partition wall 30, the pressure due to the weight of the device 10 is applied to the construction area during the construction of the sediment quality improvement method, so that the mixture can be mixed and stirred while increasing the density of the mixed mixture. it can.

[0025]

According to the method for improving bottom sediment using the apparatus for improving bottom sediment according to the present invention, the construction area is substantially sealed by the cage and the partition wall, so that the sediment blown up at the time of construction is located in the surrounding sea area. It is hard to pollute the surrounding sea area without leaking. In addition, the method for improving the sediment quality by the present apparatus can mix and agitate the sediment while increasing the density of the construction area, so that the construction efficiency is higher than that of the conventional apparatus.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of an apparatus for improving sediment quality according to the present invention.

FIG. 2 is a schematic bottom view of the sediment improving apparatus shown in FIG.

FIG. 3 is an illustrative sectional view of the sediment improving apparatus shown in FIG. 1;

FIG. 4 is an illustrative view showing a construction state of a bottom quality improvement method using the bottom quality improvement device shown in FIG. 1;

FIG. 5 is an illustrative view showing a construction state of a bottom quality improvement method using the bottom quality improvement device shown in FIG. 1;

6 is an illustrative view showing a construction state of a bottom quality improvement method using the bottom quality improvement device shown in FIG. 1;

FIG. 7 is an illustrative view showing a construction state of a bottom quality improvement method using the bottom quality improvement device shown in FIG. 1;

FIG. 8 is an illustrative view showing a construction state of a bottom quality improvement method using the bottom quality improvement device shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Sediment improvement apparatus 12 Unit 14 Stirring blade 16 Cage 16a Through-hole 18 Prime mover 20 Rotating shaft 22 Bearing 24 Bar member 26 Ring member 28 High-pressure water jet nozzle 30 Partition wall 30a Gap 32 Projection

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Patent Publication No. 3-8737 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) E02D 3/12 102

Claims (7)

(57) [Claims] 1. A cage arranged to surround a perimeter of a construction area; a rotating shaft held inside the cage and driven by a prime mover; and changing a spraying direction with the rotation of the rotating shaft. A high-pressure water jet nozzle for injecting high-pressure water toward the sediment, and a stirring blade for stirring the sediment blown up by the high-pressure water with the rotation of the rotating shaft. A sediment improvement in which a partition is provided in the cage to vertically separate the depth direction of the cage, and the high-pressure water jet nozzle and the stirring blade are arranged in a region surrounded by the cage, the partition, and the water bottom. apparatus. 2. The bottom according to claim 1, wherein the rotating shaft is used substantially upright with respect to the bottom, and the high-pressure water is injected at an oblique angle to the bottom. Quality improvement equipment. 3. The sediment according to claim 1, wherein a distance between the tip of the stirring blade and the inner wall of the cage is at least larger than the diameter of the volcano rake. Improved equipment. 4. Surrounding above and around the sand mud and sediment at the bottom of the water in a substantially sealed state,
A method for improving sediment, comprising stirring and mixing water, sand and mud and sediment by stirring with a stirring blade, and then allowing the mixture to settle. 5. A lowering step of lowering a cage having a sealed area capable of applying a pressure by its own weight and capable of being substantially sealed to the sediment on which the sediment has been deposited, and injecting high-pressure water to the sediment to blow up the cage. A cultivation step of crushing and cultivating the sediment, a stirring and mixing step of stirring and mixing the sediment and the sediment crushed and cultivated in the cultivation step with a stirring blade, and sealing the cage. A method of improving sediment, comprising: a sedimentation step of sedimenting a stirred mixture of the sediment and the sediment by consolidating a region. 6. A step of lowering a cage having a sealed area capable of applying pressure by its own weight and having a substantially hermetic seal, to a sediment on which a deposit composed of a volcanic ash layer including volcanic ash and volcanic rubble is deposited, A cultivation step of crushing and cultivating the sediment by jetting high-pressure water by a high-pressure water jet nozzle and rotation of the stirring blades, the sediment and the sediment crushed and cultivated in the cultivation step A stirring step of stirring with a stirring blade, and a sedimentation step of sedimenting a stirring mixture of the sediment and the sediment by consolidating the closed area of the cage, wherein the closed area is such that the cage bottoms on a water floor. When you do
A method of improving sediment, characterized in that the cage is formed in a substantially closed state by a partition surrounded by a partition that vertically separates a depth direction of the cage, an inner wall of the cage, and the water bottom. 7. The method for improving bottom sediment according to claim 5, further comprising a positioning step of landing and positioning the cage in a predetermined construction area of the bottom sediment.