JP7369041B2 - How to install linear body - Google Patents

Description

The present invention relates to a method for installing a linear body in the ground.

When constructing a civil engineering structure, a linear body is sometimes installed in the ground and used to detect the state of the ground. Patent Document 1 discloses a method of installing an optical fiber cable in the ground as a linear body for measuring displacement of the ground.

In the method disclosed in Patent Document 1, a pipe with an optical fiber cable attached to the outer circumference is inserted into a borehole formed in the ground, and a grout hose is inserted between the outer circumference of the pipe and the inner wall of the borehole. Fiber optic cables are installed in the ground by injecting grout through them.

Japanese Patent Application Publication No. 2002-156215

In the method disclosed in Patent Document 1, a pipe is provided over the range where the optical fiber cable is installed. That is, it is necessary to leave the pipe in the ground in a state where the pipe is placed adjacent to the optical fiber cable in the borehole. For this reason, the deeper the borehole is, the longer the pipe left in the ground becomes, which may increase the amount of pipe material consumed.

An object of the present invention is to efficiently install a linear body in the ground.

The present invention is a method for installing a linear body in which an optical fiber cable is installed in a hole formed in the ground. an insertion step of connecting a holding unit having a diameter-expanding body to one end of the extension member and inserting the holding unit into the hole by sequentially adding extension members; A fixing process in which the holding body is fixed in the hole by expanding its diameter outward, a removal process in which the holding unit and the extension member are uncoupled and the extension member is taken out from the hole, and a filling process in which the hole is filled with filler. and filling the filler material through the extension member that is removed from within the hole.

The present invention also provides a method for installing a linear body in which an optical fiber cable is installed in a hole formed in the ground, which includes a holder for holding a part of the optical fiber cable, and a water absorbing body provided on the outer periphery of the holder. an insertion step in which a holding unit having an expandable material is coupled to one end of the extension member, and the holding unit is inserted into the hole by sequentially adding extension members; A fixing step of fixing the body in the hole, a removing step of releasing the connection between the holding unit and the extension member and taking out the extension member from the hole, and a filling step of filling the hole with a filler, The filler material is filled through the extension member which is removed from within the hole.

According to the present invention, the linear body can be efficiently installed in the ground.

It is a figure showing the linear object installed in the hole by the linear object installation method concerning a 1st embodiment of the present invention. FIG. 3 is a diagram illustrating a linear object installation method according to the first embodiment of the present invention in chronological order. FIG. 3 is a diagram illustrating the linear body installation method according to the first embodiment of the present invention following FIG. 2 in chronological order. It is a figure which shows the linear object installed in the hole by the linear object installation method based on 2nd Embodiment of this invention.

EMBODIMENT OF THE INVENTION Hereinafter, with reference to drawings, the linear object installation method based on embodiment of this invention is demonstrated.

<First embodiment>
First, with reference to FIGS. 1 to 3, a linear object installation method according to the first embodiment will be described. Here, a case where the linear body is an optical fiber cable will be described. In addition to optical fiber cables, examples of the linear body include electric wires that are linear members that can measure temperature, strain, etc. with high precision.

When constructing civil engineering structures, it is important to understand ground conditions such as landslides, and optical fiber cables are sometimes installed in boreholes drilled into the ground to measure underground distortion. Optical fiber cables buried in boreholes become distorted due to underground distortion. Therefore, by measuring the strain in the optical fiber cable, it is possible to measure the strain in the ground.

Specifically, optical fiber cables have the property of slightly scattering the incident pulsed light backwards, and by utilizing this property, it is possible to measure strain at multiple positions in the optical fiber cable. be. Since the frequency of the scattered light depends on the distortion of the optical fiber cable, the distortion of the optical fiber cable can be measured by injecting pulsed light into the optical fiber cable and measuring the frequency of the scattered light. In addition, by measuring the time it takes for the scattered light generated within the optical fiber cable to return to the incident position after pulsed light is input into the optical fiber cable, it is possible to determine the position where the scattered light occurs, that is, the distortion in the optical fiber cable. The resulting position can be measured.

Therefore, by burying an optical fiber cable in a borehole drilled in the ground and measuring the strain on the buried optical fiber cable, it is possible to measure the strain in the ground that occurs at multiple locations. As a result, the condition of the ground can be accurately grasped.

A method for installing an optical fiber cable into a borehole drilled in the ground is to run the optical fiber cable along pipe material and insert the optical fiber cable into the borehole by sequentially adding pipe material. is possible.

However, in this method, the pipe material is provided over the range where the optical fiber cable is installed, that is, the pipe material is left adjacent to the optical fiber cable in the borehole.

For this reason, the deeper the borehole, the longer the pipe material left in the ground, which may increase the amount of pipe material consumed and increase the installation cost of the optical fiber cable.

In addition, if a relatively rigid member such as a pipe material is left adjacent to the optical fiber cable, the pipe material will prevent ground displacement from being transmitted to the optical fiber cable, and as a result, the There is a risk that the fiber cable may make it impossible to accurately grasp the ground condition.

For these reasons, in the linear body installation method according to the present embodiment, as shown in FIGS. 1 to 3, the first extension pipe (extension member ) 21 and a second extension pipe (extension member) 22 to install the optical fiber cable (wire body) 12, the optical fiber cable 12 is inserted into the borehole 2. After that, the extension unit 20 is taken out from the borehole 2, and the first extension pipe 21 and the second extension pipe 22 are not installed in the area where the optical fiber cable 12 is installed. FIG. 1 schematically shows the state of an optical fiber cable 12 installed in a borehole 2 and a holding unit 10 that holds a part of the optical fiber cable 12 by the linear object installation method according to the first embodiment. (A) to (C) of FIG. 2 and (A) to (C) of FIG. 3 are diagrams showing the linear body installation method according to the first embodiment in chronological order. be.

First, with reference to FIG. 1, a holding unit 10 that holds an optical fiber cable 12 installed in a borehole 2 and a part of the optical fiber cable 12 will be described using a linear object installation method that will be described in detail later.

The holding unit 10 includes a holding body 11 that holds a part of the optical fiber cable 12, and a water-absorbing and expanding material (diameter expanding body) 13 provided on the holding body 11 and capable of expanding in diameter outward in the radial direction of the borehole 2. have

The holder 11 is a cylindrical member having a hollow part 11a inside, and has an opening 11b for passing the tip end 12a of the optical fiber cable 12 into the hollow part 11a, and a first extension pipe 21. It further has a coupling part 11c to which the coupling part 11c is screwed.

The water-absorbing and expanding material 13 is a packer material that expands by absorbing liquid such as water, and is arranged so as to surround the outer peripheral surface of the holder 11 . Note that FIG. 1 shows a state in which the water-absorbing and expanding material 13 is expanded radially outward of the borehole 2. As shown in FIG. After being inserted into the borehole 2 in this way, the water-absorbing and expanding material 13 absorbs liquid such as water remaining in the borehole 2 and expands toward the outside in the radial direction of the borehole 2, so that the holding body 11 is fixed relative to the borehole 2.

The optical fiber cable 12 held by the holder 11 is a linear member in which an optical fiber (not shown) and a steel wire are covered with a resin material. The distal end portion 12a of the optical fiber cable 12 is sealed with a sealing material such as silicon to prevent reflection from occurring at the distal end surface.

The distal end 12a of the optical fiber cable 12 is inserted into the hollow portion 11a through the opening 11b of the holder 11 and fixed with an adhesive or the like. By accommodating the distal end 12a of the optical fiber cable 12 inside the holder 11 in this way, when the optical fiber cable 12 is inserted into the borehole 2, the closed distal end 12a is prevented from being damaged. This can prevent damage or damage. On the other hand, the other end of the optical fiber cable 12 is connected to a measuring device 50.

Note that what is held by the holder 11 is not limited to the distal end portion 12a of the optical fiber cable 12, but may also be a folded portion of the optical fiber cable 12. In this case, both ends of the optical fiber cable 12 are connected to the measuring device 50. Furthermore, the optical fiber cable 12 may be directly fixed to the holder 11 or may be indirectly fixed via an attachment member or the like.

The borehole 2 into which the optical fiber cable 12 has been inserted together with the holding unit 10 is filled with grout (filling material) 40 such as cement bentonite, so that the optical fiber cable 12 is fixed in the borehole 2 and the ground 1 It becomes almost integrated. Note that the liquid such as water that remains in the borehole 2 is replaced by the filled grout (filler) 40.

Next, with reference to FIGS. 2 and 3, a method for installing the optical fiber cable 12 in the borehole 2 as shown in FIG. 1 will be described.

First, with reference to FIG. 2(A), the borehole 2 in which the optical fiber cable 12 is installed will be described.

The borehole 2 is previously excavated vertically downward in the ground 1 by an excavator (not shown), and as shown in FIG. In order to prevent the ground 1 from collapsing, the excavation unit 60 used during excavation is left behind. The drilling unit 60 mainly includes a plurality of drilling rods 62 connected to each other and a drilling bit 61 attached to the tip of the drilling rod 62. It is formed from members. Therefore, the drilling unit 60 secures a space in the borehole 2 into which the optical fiber cable 12 and the like can be inserted.

Subsequently, as shown in FIGS. 2(B) and 2(C), the holding unit 10 and the optical fiber cable 12 are inserted into the borehole 2 in which the excavating unit 60 is left.

Specifically, as shown in FIG. 2(B), first, one end of the first extension pipe 21 is screwed onto the joint portion 11c of the holder 11, so that the first extension pipe 21 is held at one end. The unit 10 is in a connected state, and the holding unit 10 and the optical fiber cable 12 partially held by the holding unit 10 gradually enter the inside of the drilling rod 62 left in the borehole 2. inserted.

Note that at this stage, the diameter of the water-absorbing and expanding material 13 has not yet expanded. The water-absorbing and expanding material 13 absorbs liquid such as water staying in the borehole 2 over time, and expands in diameter over time. Therefore, by setting the maximum outer diameter of the water-absorbing and expanding material 13 in its unexpanded state to be smaller than the inner diameter of the drilling rod 62, the holding unit 10 can be easily inserted into the drilling rod 62. .

In order to insert the holding unit 10 and the optical fiber cable 12 deeper, a second extension pipe 22 is added to the first extension pipe 21, as shown in FIG. 2(C). Another second extension pipe 22 is further added.

Note that when performing the work of adding the second extension pipe 22, the end of the first extension pipe 21 or the second extension pipe 22, which has already been inserted into the borehole 2, is held in advance by a holder (not shown). Ru. By holding the end of the first extension pipe 21 or the second extension pipe 22 to which the second extension pipe 22 is to be added, the holding unit 10 can be prevented from falling into the borehole 2 when performing the addition work. It is possible to prevent this from happening.

By sequentially adding the second extension pipes 22, the holding unit 10 eventually reaches the bottom surface 2a of the borehole 2, and the insertion process is completed.

After the insertion process is completed, a fixing process for fixing the holding unit 10 in the borehole 2 is then performed.

Specifically, as shown in FIG. 3(A), when the holding unit 10 reaches the bottom surface 2a of the borehole 2, the excavating unit 60 is pulled up by a predetermined length L1. The predetermined length L1 is longer than the length from the lower surface of the holding unit 10 to the upper end of the water-absorbing and expanding material 13, and is such a length that the water-absorbing and expanding material 13 is completely exposed to the inner circumferential wall of the borehole 2. Set.

By pulling up the excavation unit 60 by the predetermined length L1 in this manner, a space is secured in which the water-absorbing and expanding material 13 can expand radially outward. Note that in order to secure a space for the water-absorbing and expanding material 13 to expand, the excavation unit 60 may be completely pulled out from inside the borehole 2; If earth and sand flows into the surrounding area, the expansion state of the water-absorbing and expanding material 13 will vary in the circumferential direction, which may make it difficult to reliably fix the holder 11 to the borehole 2. Therefore, it is preferable to maintain the excavation unit 60 in a state where it is pulled up by a predetermined length L1 until the water-absorbing and expanding material 13 is sufficiently expanded.

Until the water-absorbing and expanding material 13 sufficiently expands radially outward of the borehole 2, for example, for about 12 hours, the excavation unit 60 is left in a state where it is pulled up by a predetermined length L1. After the water-absorbing and expanding material 13 has sufficiently expanded, the excavating units 60 are sequentially pulled out from above and removed. Note that the removed excavation unit 60 is reused to excavate another borehole 2.

FIG. 3B shows a state in which the fixing step of fixing the holding body 11 in the borehole 2 by expanding the water-absorbing and expanding material 13 has been completed, and the excavation unit 60 has been removed.

When the fixing process is completed as shown in FIG. 3(B), a taking-out process for taking out the extension unit 20 from the borehole 2 is then performed as shown in FIG. 3(C).

Here, in this embodiment, the connection between the holder 11 and the first extension pipe 21, the connection between the first extension pipe 21 and the second extension pipe 22, and the connection between the second extension pipes 22 are all The direction of rotation when the holder 11 and the first extension pipe 21 are screwed together is the same as the direction of rotation when the first extension pipe 21 and the second extension pipe 22 are screwed together. The rotation direction is set to be opposite to the direction of rotation when the two extension pipes 22 are screwed together.

Specifically, the holder 11 and the first extension pipe 21 are screwed together with a left-hand thread, and the first extension pipe 21 and the second extension pipe 22 are screwed together, and the second extension pipes 22 are screwed together. is a right-handed thread.

Therefore, when the extension unit 20 is rotated to the right while the holder 11 is fixed to the borehole 2 via the water-absorbing and expanding material 13 as shown in FIG. Only the connection between the holding body 11 and the first extension pipe 21 is released.

Therefore, as shown in FIG. 3(C), the extension units 20 that have been disconnected from the holder 11 can be sequentially taken out from above in the removal process.

Further, since the extension unit 20 that is taken out from the borehole 2 into which the holding unit 10 and the optical fiber cable 12 are inserted is also a hollow tubular body, it is necessary to fill the borehole 2 with the grout 40 through the inside thereof. is also possible.

Therefore, in this embodiment, as shown in FIG. 3(C), the grout 40 is filled into the borehole 2 through the interior of the extension unit 20 while the extension unit 20 is taken out from the borehole 2 .

Specifically, as shown by the arrow in FIG. 3(C), the grout 40 is fed into the borehole 2 through the inside of the second extension pipe 22 and from the opening at the tip of the first extension pipe 21. The grout 40 is gradually filled from the bottom surface 2a side. Further, liquid such as water that remains in the borehole 2 is replaced with the grout 40 as the grout 40 is filled.

In this way, by feeding the grout 40 through the extension unit 20 while taking out the extension units 20 one after another, the borehole 2 can be efficiently filled with the grout 40, and liquid such as water can be filled into the borehole 2. Since the accumulation of water and air is suppressed, there is no need to provide a separate means for removing liquid such as water or air, and as a result, the cost of installing the optical fiber cable 12 can be reduced. . Further, the extracted extension unit 20 is reused to install the optical fiber cable 12 in another borehole 2. Therefore, the installation cost of the optical fiber cable 12 can be reduced.

In the filling process, when the borehole 2 is filled with the grout 40, as shown in FIG. The state will be as follows.

In this way, the strain in the ground around the borehole 2 in which the optical fiber cable 12 is installed is transmitted to the optical fiber cable 12 from the inner wall surface of the borehole 2 through the solidified grout 40. Therefore, by measuring the strain of the optical fiber cable 12 installed in the borehole 2 as described above, the position and magnitude of the strain underground can be measured. Note that the strength and rigidity of the grout 40 interposed between the ground 1 and the optical fiber cable 12 are approximately the same as the strength and rigidity of the ground 1, considering the transferability of underground distortion etc. to the optical fiber cable 12. Or adjusted slightly smaller than that.

According to the first embodiment described above, the following effects are achieved.

According to the linear body installation method according to the present embodiment, in the fixing step, by fixing the holding unit 10 that holds a part of the optical fiber cable 12 to the borehole 2 with the water-absorbing and expanding material 13, the holding unit 10 into the borehole 2 is taken out from the borehole 2 in the extraction process.

By taking out the extension unit 20 from the borehole 2 without leaving it in the borehole 2 in this way, the extension unit 20 that has been taken out can be reused for installing other optical fiber cables 12. Become. As a result, the installation cost of the optical fiber cable 12 can be reduced.

Further, by removing the extension unit 20 from the borehole 2, only the solidified grout 40 is interposed between the inner wall surface of the borehole 2 and the optical fiber cable 12. Therefore, the pipe material does not prevent the displacement of the ground from being transmitted to the optical fiber cable 12, so that the condition of the ground can be accurately grasped by the optical fiber cable 12.

In the first embodiment, the holding body 11 is fixed to the borehole 2 by expanding the water absorbing and expanding material 13, which expands by absorbing liquid such as water, outward in the radial direction of the borehole 2. ing. Alternatively, the configuration that expands outward in the radial direction of the borehole 2 may be, for example, one that expands by being supplied with a fluid such as water or air from the outside. In this case, the time required to fix the holder 11 is shortened, so that the optical fiber cable 12 can be installed in the borehole 2 efficiently.

Further, in the first embodiment, the borehole 2 is filled with the grout 40 through the extension unit 20. Alternatively, filling of the grout 40 may be performed by delivering the grout 40 into the borehole 2 through a separately provided filling hose. Further, in the first embodiment, the filling process is performed after the insertion process, but the borehole 2 is filled with the grout 40 before the insertion process, and the borehole 2 filled with the grout 40 is filled with the grout 40. A fiber optic cable 12 and a holding unit 10 may be inserted therein.

<Second embodiment>
Next, with reference to FIG. 4, a method for installing a linear body according to a second embodiment of the present invention will be described. In the following, differences from the first embodiment will be mainly explained, and the same or equivalent configurations as those explained in the first embodiment will be given the same reference numerals as in the first embodiment, and the explanation will be omitted. .

In the linear body installation method according to the second embodiment, the holding unit 110 inserted into the borehole 2 is rotated by a diameter expansion mechanism (diameter expansion body) 15 that can expand the diameter outward in the radial direction of the borehole 2. This is mainly different from the holding unit 10 inserted into the borehole 2 in the linear body installation method according to the first embodiment in that it is fixed in the hole 2 . Note that FIG. 4 schematically shows the state of the optical fiber cable 12 installed in the borehole 2 and the holding unit 110 that holds a part of the optical fiber cable 12 by the linear object installation method according to the second embodiment. FIG.

As shown in FIG. 4, the holding unit 110 includes a holding body 11 that holds a part of the optical fiber cable 12, and a diameter expanding mechanism (expanding mechanism) provided on the holding body 11 that can expand the diameter outward in the radial direction of the borehole 2. diameter body) 15.

Like the holder 11 in the first embodiment, the holder 11 is a cylindrical member having a hollow part 11a inside, and allows the distal end 12a of the optical fiber cable 12 to be inserted into the hollow part 11a. It further includes an opening 11b for passing through, and a coupling part 11c into which the first extension pipe 21 is screwed.

The diameter expanding mechanism 15 includes a leading member 16 that is disposed on the side opposite to the coupling portion 11c with respect to the holding body 11, and a connecting member 17 that connects the leading member 16 and the holding body 11. The connecting member 17 has a bent portion 17a that is bent depending on the size of the gap between the preceding member 16 and the holder 11.

When the holding unit 110 is inserted into the borehole 2, that is, when inserted into the drilling unit 60, the connecting member 17 extends along the insertion direction, and connects the leading member 16 and the holding body 11. The leading member 16 is held at a predetermined distance from the holder 11 so that a gap of a predetermined size is formed between the leading member 16 and the holding member 11 . Therefore, when the holding unit 110 is inserted into the borehole 2, the leading member 16 is inserted into the borehole 2 before the holder 11, and is inserted into the bottom surface 2a of the borehole 2 before the holder 11. will be reached.

In the connecting member 17, after the preceding member 16 reaches the bottom surface 2a of the boring hole 2, the holding body 11 is further pushed toward the bottom surface 2a, and the gap between the preceding member 16 and the holding body 11 in the insertion direction is small. Then, it is bent radially outward at the bending portion 17a.

The bent portion 17a of the connecting member 17 bent toward the outside in the radial direction is stuck into the inner circumferential wall of the borehole 2, as shown in FIG. In this manner, a portion of the connecting member 17 provided on the holder 11 pierces the inner circumferential wall of the borehole 2, whereby the holder 11 is fixed to the borehole 2.

Regarding the method for inserting the holding unit 110 having the above configuration into the borehole 2 and installing the optical fiber cable 12 in the borehole 2, the method for installing the optical fiber cable 12 in the first embodiment and the fixing step are as follows. As described above, the only difference is the specific method of expanding the diameter of the diameter expanding mechanism (diameter expanding body) 15, and the other steps are the same. Therefore, the explanation thereof will be omitted.

In the first embodiment, in order to securely fix the holding body 11 to the borehole 2 in the fixing step, it was necessary to wait for the expansion of the water-absorbing and expanding material 13, but in this embodiment, After the preceding member 16 reaches the bottom surface 2a of the borehole 2, the holder 11 is further pushed toward the bottom surface 2a, and the bent portion 17a of the connecting member 17 is pierced into the inner circumferential wall of the borehole 2. is immediately fixed to the borehole 2. Therefore, it takes almost no time to fix the holder 11 in the borehole 2, so that the optical fiber cable 12 can be installed efficiently.

According to the second embodiment described above, the following effects are achieved.

According to the linear body installation method according to the present embodiment, in the fixing step, by fixing the holding unit 110 that holds a part of the optical fiber cable 12 to the borehole 2 by the diameter expanding mechanism 15, the holding unit Pipe materials such as the extension unit 20 used when inserting the pipe 110 into the borehole 2 are taken out from the borehole 2 in the extraction process.

By taking out the extension unit 20 from the borehole 2 without leaving it in the borehole 2 in this way, the extension unit 20 that has been taken out can be reused for installing other optical fiber cables 12. Become. As a result, the installation cost of the optical fiber cable 12 can be reduced.

Further, by removing the extension unit 20 from the borehole 2, only the solidified grout 40 is interposed between the inner wall surface of the borehole 2 and the optical fiber cable 12. Therefore, the pipe material does not prevent the displacement of the ground from being transmitted to the optical fiber cable 12, so that the condition of the ground can be accurately grasped by the optical fiber cable 12.

In the second embodiment, the holder 11 is fixed to the borehole 2 by utilizing the radially outward deformation of the connecting member 17 that bends under load. Alternatively, the diameter expanding mechanism may utilize elastic deformation; for example, the diameter expanding mechanism may be a plate spring whose one end is coupled to the outer circumferential surface of the holder 11 and whose other end is a It is inserted into the excavation unit 60 in a compressed and deformed state toward the body 11, and the other end is configured to extend radially outward with restoring force when the excavation unit 60 is pulled up. Good too. In this case, the holding body 11 is fixed to the borehole 2 by the restoring force of the other end of the leaf spring sticking into the inner circumferential wall of the borehole 2 .

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. do not have.

For example, in each of the above embodiments, the linear body is an optical fiber cable 12, but the linear body installed in the borehole 2 is not limited to this, and the state of the ground 1 can be detected. Any linear body may be used as long as it is a linear body, for example, a linear body in which multiple sensors capable of detecting pressure or temperature are connected at equal intervals, or a metal wire such as a thermocouple may be used. . Furthermore, the detected state of the ground 1 is not limited to underground distortion, but may also be underground temperature or pressure.

Further, in each of the above embodiments, a case has been described in which the borehole 2 is drilled vertically downward, but the borehole 2 may be bored vertically upward, or horizontally or horizontally. It may be excavated upward or downward at a predetermined angle from the direction. Even when the borehole 2 is drilled in this way, it is possible to install the optical fiber cable 12 inside the borehole 2 by the above-described method.

Furthermore, in each of the above embodiments, the holding units 10 and 110 are inserted into the excavation unit 60 left in the borehole 2. However, if there is no risk of the ground 1 collapsing, The drilling unit 60 may be removed and then the holding unit 10, 110 may be inserted into the borehole 2.

1... Ground 2... Borehole (hole)
10, 110... Holding unit 11... Holding body 12... Optical fiber cable (linear body)
13...Water absorption and expansion material (diameter expansion body)
15... Diameter expansion mechanism (diameter expansion body)
20... Extension unit (extension member)
21...First extension pipe (extension member)
22...Second extension pipe (extension member)
40... Grout (filling material)
50...Measuring device 60...Drilling unit

Claims (3)

A linear body installation method for installing an optical fiber cable in a hole formed in the ground,
A holding unit having a holding body that holds a part of the optical fiber cable and a diameter expanding body provided on the holding body and capable of expanding the diameter outward in the radial direction of the hole is coupled to one end of the extension member, an insertion step of inserting the holding unit into the hole by sequentially adding extension members;
a fixing step of expanding the diameter of the diameter-expanding body radially outward and fixing the holding body within the hole;
an extraction step of releasing the connection between the holding unit and the extension member and taking out the extension member from within the hole;
a filling step of filling the hole with a filler ,
The filling material is filled through the extension member taken out from within the hole.
How to install a linear body. A linear body installation method for installing an optical fiber cable in a hole formed in the ground,
A holding unit having a holding body that holds a part of the optical fiber cable and a water-absorbing and expanding material provided on the outer periphery of the holding body is coupled to one end of the extension member, and the extension members are successively added. an insertion step into the hole;
a fixing step of fixing the holding body in the hole by expanding the water-absorbing and expanding material in a radial direction;
an extraction step of releasing the connection between the holding unit and the extension member and taking out the extension member from within the hole;
a filling step of filling the hole with a filler ,
The filling material is filled through the extension member taken out from within the hole.
How to install a linear body. The connection between the holding unit and the extension member and the connection between the extension members are each screwed,
The direction of rotation when the holding unit and the extension member are screwed together is opposite to the direction of rotation when the extension members are screwed together.
The linear body installation method according to claim 1 or 2 .

Images