JP3289063B2 - Construction method of underwater mound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a mound on a water bottom using a slurry-like mud such as dredged sludge or excavated mud.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 6-136732 discloses a method of constructing a water bottom structure using excavated mud or the like. And a method of constructing a levee body for injecting and filling excavated sludge from the water into each bag body is disclosed.
Japanese Patent Publication No. 136733 discloses a method of constructing a bank body in which excavated sludge is injected and filled in water into a substantially straight continuous flexible bag, and the bags are stacked and installed on the water bottom.

[0003]

In the above-described method of constructing a bank using a flat, substantially planar bag, the manufacturing cost is presumed to increase as the area of the bag increases. Is not economical to apply to underwater structures, while the construction method of embankments using substantially straight continuous bags is relatively expensive because the stacked bags are not connected to each other. It is considered technically difficult to apply to underwater structures that require strength. Also, in both construction methods, the excavated sludge is only injected and filled in the flexible bag body, so it is presumed that its strength is not so high, and it is applied to a water bottom structure requiring relatively high strength. It is considered difficult.

An object of the present invention is to suitably construct a water bottom mound having a relatively large area and a relatively high strength using slurry-like mud such as dredged sludge and excavated mud.

[0005]

SUMMARY OF THE INVENTION The features of the present invention for solving the conventional problems as described above and achieving the intended purpose are as follows.
In the form of a flexible sheet, a mud covering member provided with a mud inlet penetrating vertically, and in the form of a flexible bag,
A mud holding member consisting of a submerged fixing member provided with a mud inlet that penetrates inward and outwardly is fixed to the periphery of the mud covering member in an annular shape, and is placed on the water bottom, and slurry-type mud is supplied from above the water. It is an object of the present invention to inject slurry-like mud into the water-bottom fixing member and fix it to the water bottom, and to inject the slurry-like mud below the mud covering member.

The mud covering member is formed in a double structure in which the upper surface side is impermeable and the lower surface side is permeable. The mud covering member is provided with a drain port vertically penetrating therethrough. After the slurry-like mud is poured into the lower part of the mud covering member, the slurry-like mud below the mud covering member is consolidated and dewatered by hydraulic pressure through the mud covering member. Preferably, it is injected.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 to 4, a mud holding member used for constructing a water bottom mound includes a flexible sheet-like mud covering member 4 and a flexible bag-like mud covering member. And a water bottom fixing member 5.

The mud covering member 4 has a double structure in which the upper surface side is formed of a water-impermeable material and the lower surface side is formed of a water-permeable material. 4a, a drain port 4b is provided,
A mud injection pipe 6 and a drain pipe 7 are connected to each other. Further, the water bottom fixing member 5 is fixed to the periphery of the mud covering member 4 in a ring shape, and the water bottom fixing member 5 is provided with a mud injection port penetrating in and out similarly to the mud covering member 4. An injection pipe is connected.

In order to construct a water bottom mound, first, FIG.
As shown in the figure, the mud holder is placed on the water bottom 0, and the curable slurry mud 2 is supplied from the work boat 1 on the water via a mud injection pipe, and the slurry mud 2 is placed in the water bottom fixing member 5. And filling. Then, the water bottom fixing member 5 is fixed to the water bottom 0 by the weight of the slurry mud 2, and the gap between the peripheral edge of the mud covering member 4 and the water bottom 0 is sealed via the water bottom fixing member 5. Note that the water bottom fixing member 5 may be fixed to the water bottom via an anchor or the like.

Next, as shown in FIG. 2, the hardening slurry-like mud 2 is supplied from the workboat 1 on the water via a mud pouring pipe 6, and is provided below the mud covering member 4, that is, the mud covering member 4 The slurry-like mud 2 is injected and deposited between the ground and the water bottom 0. At this time, the water below the mud covering member 4 is drained through the drain pipe 7.

When a certain amount of the slurry-like mud 2 is filled below the mud covering member 4, the injection of the slurry-like mud 2 is temporarily stopped. Then, as shown in FIG. 3, water pressure is applied below the flexible mud covering member 4, so that the slurry-like mud 2 below the mud covering member 4 is compacted and dewatered by water pressure to have a volume. As it decreases, the strength increases. At this time, since the lower surface side of the mud covering member 4 has water permeability, the water discharged from the slurry mud 2 can be suitably guided to the drain port 4b and the drain pipe 7. In addition, the water level in the drainage pipe 7 can be reduced by a pump to promote consolidation.

When the consolidation of the slurry-like mud 2 under the mud covering member 4 proceeds and the volume decreases, as shown in FIG. 4, the slurry-like mud 2 is again transferred from the workboat 1 on the water to the mud injection pipe 6. And the slurry-like mud 2 is injected and filled below the mud covering member 4. Then, the slurry-like mud 2 under the mud covering member 4 is again compacted and dewatered by hydraulic pressure. As described above, the injection and filling of the slurry-like mud 2 under the mud covering member 4 and the consolidation and dewatering of the slurry-like mud 2 under the mud covering member 4 are repeated to obtain a water bottom mound having a required strength and height. Is constructed.

[0013]

As described above, the method for constructing a water bottom mound according to the present invention comprises a flexible sheet-like mud covering member provided with a mud inlet penetrating vertically and a flexible mud covering member. In the form of a bag, the mud holding member consisting of a water bottom fixing member provided with a mud injection port penetrating inward and outwardly fixed to the peripheral portion of the mud covering member in an annular shape is placed on the water bottom, and the slurry mud is placed on the water. Slurry mud is supplied into the water bottom fixing member to be fixed on the water bottom, and the slurry mud is injected below the mud covering member, thereby reducing the production cost of the mud holding body as compared with the case where the whole is cylindrical. Therefore, the water bottom mound having a relatively large area can be suitably constructed.

Further, the mud covering member is formed in a double structure in which the upper surface side is impermeable and the lower surface side is permeable, and the mud covering member is provided with a vertically penetrating drain port, and the slurry is provided below the mud covering member. After injecting the slurry mud, the slurry mud deposited under the mud covering member is subjected to water pressure through the mud covering member to consolidate dewatering, and then re-injecting the slurry mud below the mud covering member. Thereby, the strength of the slurry-like mud deposited below the mud covering member can be increased, and a water bottom mound having relatively high strength can be suitably constructed.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a method for constructing a water bottom mound according to the present invention, showing a step of injecting slurry-like mud into a water bottom fixing member.

FIG. 2 is a vertical sectional view showing an embodiment of a method of constructing a water bottom mound according to the present invention, showing a step of injecting slurry mud under a mud covering member.

FIG. 3 is a vertical sectional view showing an embodiment of the method of constructing a water bottom mound according to the present invention, showing a step of compacting slurry-like mud under a mud covering member.

FIG. 4 is an embodiment of the method for constructing a water bottom mound according to the present invention, and is a vertical sectional view showing a step of re-injecting slurry-like mud under a mud covering member.

[Explanation of symbols]

 0 Water bottom 1 Workboat 2 Slurry mud 4 Mud covering member (mud holding body) 4a Mud injection port 4b Drain port 5 Water bottom anchoring member (mud holding body) 6 Mud injection pipe 7 Drain pipe

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-136733 (JP, A) JP-A-6-136732 (JP, A) JP-A-1-99677 (JP, A) JP-A-3-136 158521 (JP, A) JP-A-62-153407 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02B 3/00 E02D 15/10

Claims (2)

(57) [Claims] 1. A mud covering member having a flexible sheet-like shape and provided with a mud inlet penetrating vertically, and a flexible bag-like member fixed in a ring shape to a peripheral portion of the mud covering member. A mud holding body composed of a water bottom fixing member provided with a mud inlet penetrating inside and outside is placed on the water bottom, and slurry mud is supplied from above the water, and the slurry mud is injected into the water bottom fixing member. A method of constructing a water bottom mound, wherein the slurry is fixed to the water bottom and the slurry-like mud is injected below the mud covering member. 2. The mud covering member is formed in a double structure in which an upper surface side is impermeable and a lower surface side is permeable, and the mud covering member is provided with a drain port vertically penetrating therethrough. After the slurry-like mud is poured into the lower part of the mud covering member, the slurry-like mud below the mud covering member is consolidated and dewatered by hydraulic pressure through the mud covering member. The method according to claim 1, wherein the mound is injected.