JP7477415B2 - Anchor material and drainage method using same - Google Patents

Description

The present invention relates to an anchor material that is attached to a drain material that is cast into soft ground, and a drain construction method that uses the same.

In a drainage method for improving soft ground, a strip-shaped drain material such as a paper drain or plastic drain is installed in a casing with an anchor material attached to its tip, and the casing is used to install the material in the soft ground. In this method, a phenomenon called "co-rising" can occur when the casing is pulled out. In other words, this phenomenon occurs when the anchor material that should be fixed in the ground adheres to the tip of the casing due to soil and sand seeping into the casing and restraining the drain material, causing the drain material to be pulled up together with the casing. When this phenomenon occurs, the drain material needs to be re-installed, and measures to prevent co-rising are required. For example, Patent Document 1 discloses a method for monitoring the co-rising of the drain material by photographing the state of the drain material with a photographing device installed inside the casing.

JP 2016-61079 A

In addition, specific measures to prevent co-rise include increasing the pressure-receiving area of the anchor material that is attached to the drain material and left in the ground, but there is a limit to how much this can be expanded because it leads to an increase in resistance when the casing penetrates.
The present invention has been made in consideration of the above problems, and an object of the present invention is to prevent the drain material from rising together and improve construction efficiency.

(Mode of the invention)
The following aspects of the invention are illustrative of the configuration of the present invention, and are described in terms of items to facilitate understanding of the various configurations of the present invention. Each item does not limit the technical scope of the present invention, and the technical scope of the present invention may include any embodiment in which some of the components of each item are replaced or deleted, or other components are added, while taking into account the best mode for carrying out the invention.

(1) An anchor material that is installed on the tip side of a casing in a state where a drainage material is cast into soft ground using a casing and is inserted into the inside of the casing during casting and attached to a portion protruding from the tip of the casing, the anchor material having a plate shape with two sides , one side facing in the casting direction of the casing and the other side facing toward the casing, the anchor material including: a main body portion that is attached to the tip of the drainage material protruding from the tip of the casing; and an elastic body that is provided on the other side of the main body portion and is compressed between the tip of the casing and the main body portion when the casing penetrates (Claim 1).

The anchor material described in this section is used in a drainage method in which a casing is used to cast a drain material into soft ground, and is installed on the tip side of the casing in a state in which the drain material is inserted into the inside of the casing and attached to the part of the drain material protruding from the tip of the casing when the drain material is cast, and includes a plate-shaped main body having two faces and an elastic body. The plate-shaped main body is provided with a slit through which the drain material is passed , and is attached to the tip of the drain material protruding from the tip of the casing , with one face facing the casting direction at the tip of the casing and the other face facing the casing side . Furthermore, an elastic body is provided on the face of the main body opposite to the face facing the casting direction at a position where it comes into contact with and is pressed by the tip of the casing when the casing penetrates. Therefore, the elastic body is compressed between the tip of the casing that is pushed in and the main body that receives a reaction force from the ground when the casing penetrates, and a repulsive force is accumulated.

Then, immediately after the design depth is reached and the casing begins to be pulled out, the elastic body is no longer subject to the pushing force from the tip of the casing, and the accumulated repulsive force is released from the main body, returning to its original shape. The restoring force at this time acts in the opposite direction to the pushing force from the casing, i.e., in the same direction as the casing is pulled out, so it acts to separate the elastic body from the tip of the casing. Therefore, the anchor material is actively detached from the tip of the casing via the elastic body. This prevents the anchor material from adhering to the tip of the casing and also prevents the drain material from rising up together with the casing, which in turn improves the construction efficiency of the drain method because there is no need to re-drive the drain material. Moreover, the casing and drain material used in construction together with the anchor material are the same as those that have been used traditionally, so costs are kept down.

(2) In the anchor material according to the above (1), the elastic body is a plurality of leaf springs that come into contact with different positions on the tip of the casing (Claim 2).
In the anchor material described in this section, the elastic body provided in the main body is a plurality of leaf springs that contact different positions on the tip of the casing, and each of the plurality of leaf springs accumulates a repulsive force when the casing is inserted. The plurality of leaf springs release the accumulated repulsive force at the plurality of different positions that contact the tip of the casing when the casing is pulled out, effectively separating the anchor material from the tip of the casing. Therefore, while utilizing a simple mechanism of leaf springs, adhesion of the anchor material to the tip of the casing and lifting up of the drain material are more effectively prevented.

(3) In the above (2), the plurality of leaf springs are anchor materials formed by cutting and raising a part of the main body (Claim 3).
The anchor material described in this section has a plurality of leaf springs formed as elastic bodies in the main body by cutting and raising a part of the main body. This reduces material costs compared to when leaf springs made of separate members are attached to the main body, and therefore reduces cost increases.

(4) A drainage method using a casing to cast drainage material into soft ground, comprising: an anchor material that is inserted into the inside of the casing when the drainage material is cast, attached to a portion of the drainage material protruding from the tip of the casing , and installed on the tip side of the casing ; the anchor material has a plate shape with two sides , one side facing in the casting direction of the casing and the other side facing the casing, and includes a main body that is attached to the tip of the drainage material protruding from the tip of the casing, and an elastic body provided on the other side of the main body so as to be compressed between the tip of the casing and the main body when the casing penetrates (Claim 4).

(5) In the above (4), a drainage method is provided in which a plurality of leaf springs are provided as the elastic body, the leaf springs contacting different positions on the tip of the casing (claim 5).
(6) In the above (5), the plurality of leaf springs are formed by cutting and raising a part of the main body of the anchor material (claim 6).
The drainage methods described in items (4) to (6) are carried out using the anchor materials described in items (1) to (3) above, respectively, and thus have the same effect as the anchor materials described in items (1) to (3) above.

The present invention has the above-mentioned configuration, which makes it possible to prevent the drain material from rising together and improve construction efficiency.

1 is a perspective view showing an example of a configuration of an anchor material according to an embodiment of the present invention. 2A and 2B show the state in which the anchor material of FIG. 1 is set in a casing together with a drain material, in which (a) is a simplified cross-sectional view of the vicinity of the tip of the casing, and (b) is an enlarged image of the vicinity of the anchor material. 1 is an image diagram showing the process of pouring the casing and drainage material in a drainage method according to an embodiment of the present invention, in which (a) shows the state during pouring, and (b) shows the state after pouring to the designed depth. 1A and 1B are conceptual diagrams showing the casing removal process of the drainage method according to an embodiment of the present invention, in which (a) shows the start of removal and (b) shows the removal process. 1A and 1B are enlarged images of the vicinity of the anchor material during installation, in which (a) shows the state during the casting of the casing, and (b) shows the state immediately after the casing has started to be pulled out.

Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings. Here, detailed descriptions of the same or corresponding parts as those in the prior art will be omitted, and the same or corresponding parts are indicated by the same reference numerals throughout the drawings.
Fig. 1 shows a schematic configuration of an anchor material 10 according to an embodiment of the present invention. As with conventional anchor materials, this anchor material 10 is attached to the tip of a strip-shaped drain material 40 such as a paper drain or a plastic drain, which is driven into soft ground SG (see Figs. 3 and 4) by a casing 50, as shown in Fig. 2(a), and is left in the soft ground SG.

As shown in FIG. 1, the anchor material 10 according to the embodiment of the present invention is roughly composed of a plate-shaped main body 12 and an elastic body 30 formed by a plurality of leaf springs 32 in this embodiment. In this embodiment, the main body 12 is a rectangular plate having two long sides and two short sides in a plan view, and has two faces 12a and 12b. Two slits 14 are provided between the two faces 12a and 12b and extending parallel to the long sides of the rectangle in a plan view. These two slits 14 are portions through which the strip-shaped drain material 40 is wound to fix the anchor material 10 to the tip of the drain material 40. In addition, the main body 12 in this embodiment has both ends of the long side of the rectangle in a plan view slightly bent, forming wing portions 16 and 18 inclined toward the face 12b. From the standpoint of anchoring in the soft ground SG (see Figures 3 and 4), it is preferable that the main body 12 is larger than conventional standard-sized anchor materials; to give an example, but not limited to this, it has a short side of 140 mm, a long side of 180 mm, and a thickness of approximately 3.2 mm.

As described above, in this embodiment, the elastic body 30 is formed of multiple (four) leaf springs 32, and is provided on one surface 12b of the main body 12. Each leaf spring 32 has a base end 34 fixed to the main body 12 and a spring portion 36 extending obliquely upward from the base end 34, and the tip side of the spring portion 36 can swing up and down. In this embodiment, four leaf springs 32 are provided in parallel to the extension direction of the slits 14, with two spring portions 36 facing each other, at positions sandwiching two slits 14. In addition, such leaf springs 32 may be formed by cutting and raising a part of the main body 12, or may be separate members from the main body 12.

In the case of cut-and-raise processing, for example, a U-shaped cut is made in the main body 12 when viewed from above, and the part corresponding to the opening of the U-shape is folded, so that the part raised from the main body 12 by the folding corresponds to the spring part 36, and the base part of the fold corresponds to the base end part 34. In the case of separate members, for example, one plate-shaped part of a folded plate member is fixed to the main body 12, so that the base end part 34 is formed by the one plate-shaped part, and the spring part 36 is formed by the other plate-shaped part that is separated by the folding position. The strength of the restoring force (repulsive force) possessed by the elastic body 30 (leaf spring 32) may be determined, for example, in consideration of the size of the main body 12 and the adhesion force of soil to the main body 12.

2(a), the vicinity of the tip of the casing 50 used for pouring the drainage material 40 is illustrated, and the drainage material 40 inserted into the casing 50 from the rear end side (upper side in the figure) in preparation for pouring is shown through the inside of the casing 50. At the position protruding from the tip 50a of the casing 50 to the outside, the anchor material 10 is arranged, fixed to the tip of the drainage material 40 by wrapping the drainage material 40 through the slit 14 of the main body 12. At this time, the anchor material 10 is in a state where one surface 12a of the main body 12 faces downward in the figure (the penetration direction of the casing 50) and the other surface 12b of the main body 12 faces upward in the figure (towards the casing 50). The drain material 40 is fixed at the upper side in the figure so that it does not loosen, and the surface 12b side of the main body 12 of the anchor material 10 abuts against the tip 50a of the casing 50. Note that the elastic body 30 of the anchor material 10 is not shown in Figure 2(a).

Here, the elastic body 30 of the anchor material 10 is provided in a position that contacts the tip 50a of the casing 50 when the drain material 40 and the anchor material 10 are set in the casing 50 as described above. That is, as shown in FIG. 2(b), the spring portion 36 of the leaf spring 32 constituting the elastic body 30 in this embodiment is adapted to contact the tip 50a of the casing 50. More specifically, the spring portions 36 of the four leaf springs 32 contact different positions of the annular edge portion (50a) of the tip opening of the casing 50 from which the drain material 40 protrudes, depending on the respective installation positions as shown in FIG. 1. Note that in FIG. 2(b) and FIG. 5 described later, the shape of the vicinity of the tip 50a of the casing 50 is illustrated in a simplified form.

Next, a drainage method according to an embodiment of the present invention, which is carried out using the above-mentioned anchor material 10, will be described with reference to Fig. 3 to Fig. 5. This description will be given by taking as an example a case in which the drainage material 40 is cast from a work barge 60 on the water into soft ground SG underwater.
First, the planned driving depth of the drain material 40 is set according to the construction site, and then the work barge 60 is moved to an appropriate position for driving the drain material 40 to the design position. Then, as shown in Fig. 2, the anchor material 10 attached to the tip of the drain material 40 is installed at the tip 50a of the casing 50, and the casing 50 is penetrated from the tower 62 of the work barge 60 as shown in Fig. 3(a), and the drain material 40 is driven into the soft ground SG in the water. At this time, the drain material 40 is unwound via the reel 64 so as to follow the casing 50 whose penetration depth gradually deepens.

In this way, as the casing 50 is penetrated into the soft ground SG, the anchor material 10 is in the state shown in FIG. 5(a). That is, the elastic body 30 is compressed by the pushing force received from the tip 50a of the penetrated casing 50, as shown by the downward arrow in the figure, and the reaction force received by the main body 12 from the soft ground SG, as shown by the upward arrow in the figure. More specifically, the spring parts 36 of the four leaf springs 32 constituting the elastic body 30 are pressed against the main body 12 and become parallel to the base end 34. Then, with the anchor material 10 in the state shown in FIG. 5(a), the casing 50 is penetrated into the soft ground SG until the drain material 40 is cast to the planned depth, as shown in FIG. 3(b).

After the drain material 40 is cast to the planned depth, the casing 50 is pulled out from the soft ground SG as shown in FIG. 4(a). Then, the pushing force from the casing 50 to the anchor material 10 disappears, and at the same time, the reaction force that the main body 12 receives from the soft ground SG also disappears, so that the elastic body 30 is released from the compressed state and returns to its original shape as shown in FIG. 5(b). More specifically, the spring parts 36 of the four leaf springs 32 constituting the elastic body 30 rise from the main body 12 with the base end 34 as the base point, and exert a restoring force as shown by the upward arrow in the figure. This causes the anchor material 10 to detach from the tip 50a of the casing 50. After that, the casing 50 is continued to be pulled out as shown in FIG. 4(b) while checking for the presence or absence of the drain material 40 rising together, for example, with a drain detector (not shown). Then, in order to separate the drainage material 40 that has been cast into the soft ground SG, the drainage material 40 is cut at an appropriate position.

In the above example, the drainage material 40 is cast from a work barge 60 on the water into soft ground SG underwater, but the drainage method according to the embodiment of the present invention is not limited to this and can also be applied to casting the drainage material 40 into soft ground SG on land. In addition, the drainage method according to the embodiment of the present invention may be configured to prevent soil from entering the casing 50 by injecting water into the casing 50 when the casing 50 is inserted or removed, filling the casing 50 with water. Furthermore, the anchor material 10 according to the embodiment of the present invention used in the drainage method is not limited to the configuration shown in Figures 1 and 2.

For example, the elastic body 30 is not limited to the leaf spring 32, and may be composed of a spring of a different shape, rubber, or the like. The mounting position and mounting direction of the elastic body 30 on the main body 12 are arbitrary as long as the elastic body 30 contacts the tip 50a of the casing 50 and does not interfere with the drain material 40 attached to the main body 12 via the slit 14. Furthermore, the shape and size of the plate-shaped main body 12 are also arbitrary, and for example, the wing portions 16, 18 do not need to be formed, and a plate-shaped anchor material that has been used conventionally may be used as the main body 12.

Now, according to the embodiment of the present invention having the above configuration, it is possible to obtain the following effects. That is, the anchor material 10 according to the embodiment of the present invention is used in a drainage method in which a drain material 40 is cast into soft ground SG using a casing 50, as shown in Figures 3 and 4, and is attached to a portion of the drain material 40 protruding from the tip 50a of the casing 50 when the drain material 40 is cast, as shown in Figures 1 and 2, and includes a plate-shaped main body 12 and an elastic body 30. The plate-shaped main body 12 is provided with a slit 14 through which the drain material 40 passes, and one surface 12a of the plate-shaped main body 12 is oriented in the casting direction at the tip position of the casing 50. Furthermore, the elastic body 30 is provided on the surface 12b of the main body 12 opposite the surface 12a oriented in the casting direction, at a position where it comes into contact with and is pressed by the tip 50a of the casing 50 when the casing 50 penetrates. Therefore, when the casing 50 penetrates, the elastic body 30 is compressed between the tip 50a of the casing 50 being pushed in and the main body 12 that receives the reaction force from the ground SG, as shown in FIG. 5(a), and a repulsive force is accumulated.

Then, immediately after the design depth is reached and the casing 50 begins to be pulled out, the elastic body 30 loses the pushing force from the tip 50a of the casing 50, and the accumulated repulsive force is released from the main body 12 as shown in FIG. 5(b), and the elastic body 30 returns to its original shape. The restoring force at this time acts in the opposite direction to the pushing force from the casing 50, that is, in the same direction as the pulling direction of the casing 50, so that the elastic body 30 acts to separate from the tip 50a of the casing 50. Therefore, the anchor material 10 can be actively detached from the tip 50a of the casing 50 via the elastic body 30. This makes it possible to prevent the anchor material 10 from adhering to the tip 50a of the casing 50, and to prevent the drain material 40 from rising up together with the casing 50. In addition, since it is not necessary to re-drive the drain material 40, it is possible to improve the construction efficiency of the drain construction method. Moreover, since the casing 50 and drain material 40 used in construction together with the anchor material 10 can be the same as those used conventionally, it is also possible to suppress cost increases.

As shown in Figs. 1 and 2, the anchor material 10 according to the embodiment of the present invention has an elastic body 30 provided in the main body 12 that is a plurality of leaf springs 32 that contact the tip 50a of the casing 50 at different positions, and each of the plurality of leaf springs 32 accumulates a repulsive force when the casing 50 penetrates. The plurality of leaf springs 32 release the accumulated repulsive force at the plurality of different positions that contact the tip 50a of the casing 50 when the casing 50 is pulled out, and can effectively detach the anchor material 10 from the tip 50a of the casing 50. Therefore, while using a simple mechanism of the leaf springs 32, it is possible to more effectively prevent the anchor material 10 from adhering to the tip 50a of the casing 50 and the drain material 40 from rising up together.

Furthermore, in the anchor material 10 according to the embodiment of the present invention, the multiple leaf springs 32 are formed by cutting and raising a portion of the main body 12, so that material costs can be reduced compared to a case in which the leaf springs 32 made of separate material are attached to the main body 12, thereby making it possible to further prevent costs from increasing.
On the other hand, the drainage method according to the embodiment of the present invention is carried out using the anchor material 10 according to the embodiment of the present invention as described above, and thus can achieve the same effects as those of the anchor material 10 according to the embodiment of the present invention.

10: Anchor material, 12: Main body, 30: Elastic body, 32: Leaf spring, 40: Drain material, 50: Casing, 50a: Tip, SG: Soft ground

Claims (6)

An anchor material is installed on the tip side of a casing in a state where a drain material is driven into soft ground using a casing and is inserted into the inside of the casing when the drain material is driven and attached to a portion protruding from the tip of the casing,
A main body portion having a plate shape with two surfaces , one surface facing the pouring direction of the casing and the other surface facing the casing side, which is attached to the tip of the drain material protruding from the tip of the casing ;
and an elastic body provided on the other surface side of the main body portion, the elastic body being compressed between the tip of the casing and the main body portion when the casing is inserted. The anchor material according to claim 1, characterized in that the elastic body is a plurality of leaf springs that contact different positions on the tip of the casing. The anchor material according to claim 2, characterized in that the plurality of leaf springs are formed by cutting and raising a portion of the main body. A drainage method in which a casing is used to cast a drain material into soft ground,
A drainage construction method using an anchor material that is inserted into the inside of the casing and attached to the portion of the drain material protruding from the tip of the casing when the drain material is poured , and installed on the tip side of the casing , the anchor material being a plate -like material with two sides , one side facing in the pouring direction of the casing and the other side facing toward the casing, and including a main body portion that is attached to the tip of the drain material protruding from the tip of the casing, and an elastic body provided on the other side of the main body portion so as to be compressed between the tip of the casing and the main body portion when the casing is inserted. The drainage method according to claim 4, characterized in that the elastic body is a plurality of leaf springs that contact different positions on the tip of the casing. 6. The drainage method according to claim 5, wherein the plurality of leaf springs are formed by cutting and raising a portion of the main body of the anchor material.

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