JP4469095B2 - Communication cable laying method in underground conduit, guide tube used therefor, and underground conduit laying structure of communication cable - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
When laying communication cables in underground pipes such as sewage pipes, communication and power pipes, the present invention applies to the main pipe of the underground pipe and a plurality of branch pipes connected to the main pipe. The present invention also relates to a method for laying a communication cable in an underground conduit that makes it possible to easily enter a communication cable when necessary, a guide tube used therefor, and an underground conduit laying structure for a communication cable.
[0002]
[Prior art]
Currently, the IT strategy is sung as a national project, and the construction of a high-speed / ultra-high-speed network, which is an information transmission means, is urgently needed. The communication cable, which is the medium, is considered to be aerial and underground. However, the communication cable laying in the underground laying method is more difficult than the aerial method. It has the characteristics of protecting landscape aesthetics and being resistant to disasters such as earthquakes and typhoons. In particular, in the sewer pipe, the branch pipe (mounting pipe) connected to the main pipe has already been led to each home, and the upper part in the pipe is an empty space, and the communication cable is drawn into each home. To The Home) is attracting attention as an important infrastructure of the plan.
[0003]
On the other hand, as a communication cable, an optical fiber cable, which has much better performance than a metal cable used so far, has been attracting attention. An optical fiber cable is made of thin fibers of glass or plastic, uses light as an information carrier, and sends a signal obtained by digitalizing information such as sound and video (1, 0 signal). Compared to metal cables, optical fiber cables are superior in broadband, low loss, immunity to electromagnetic waves, light weight, small size, safety, and confidentiality, and can flow information amounts from tens to hundreds of times. It has excellent characteristics as a communication medium.
[0004]
In the FTTH project, which is a system using optical fiber cables, it is considered that each house is divided into 200 to 500 small blocks and controlled. In each block, public facilities such as public halls and dispatch stations are used as communication bases. It is assumed that an optical fiber cable will be laid to each house.
[0005]
When laying optical fiber cables in each house using sewer pipes, the optical fiber cables pass through the branch pipes from the sewer main pipe and from the branch pipes at the end of the branch pipes (sewage tanks, in residential land or on the road) Is led to each house by digging underground.
[0006]
As a technique for laying communication cables such as optical fiber cables in underground pipes such as sewer pipes, a robot method, a saddle method, a sheath pipe method, a drain method, etc. that fix the communication cable in the pipe line have been proposed. . These construction methods disclose means for laying communication cables in underground conduits, and mainly relate to laying in underground conduits.
[0007]
[Problems to be solved by the invention]
However, when laying communication cables in underground pipelines, laying one cable from a communication base to each house requires a long communication cable and complicates the laying route. Is very difficult.
[0008]
Therefore, branch cables (communication cables) of about 24 to 200 cores are laid from the communication base into the underground pipe main, and each of the manholes etc. connecting the underground pipe mains to each other is connected by a connecting branch box. Branch out a cable (communication cable) of about 2 to 4 cores (more than the housing complex) for laying up to the house. Then, a method of laying a lead-in cable from a manhole or the like from the main pipe through the branch pipe to each house is considered.
[0009]
In the future, there is a plan to lay communication cables in all the houses, but in reality, some houses are vacant and some houses do not want to be laid for the time being. Therefore, the situation where the laying time shifts by each house arises.
[0010]
The present invention has been made in view of such a background, and the laying time of the communication cable can be shifted depending on each house, and a long communication cable can be easily laid in the underground conduit. In addition, it can be installed with workability and construction cost comparable to the aerial method, the original function of the underground conduit is not hindered, and the maintenance work of the underground conduit is not adversely affected. Provided is a method for laying a communication cable in an underground conduit, a guide tube used in the underground conduit, and a structure for laying an underground conduit in a communication cable so that the communication cable is not damaged when the middle conduit is originally used or maintained and managed. Is.
[0011]
[Means for Solving the Problems]
  The method for laying a communication cable in an underground conduit according to claim 1 for solving the above-mentioned problem is as follows.Between manholesMainMultiple via branch portIn the underground pipeline where the branch pipe branchesA communication cable is laid from the manhole to the branch pipeA method,A communication cable laid in some of the plurality of branch pipes, and later in the remaining branch pipescommunication cableLayingNominal wire forMultiple filaments consisting ofIn the guide tube in advance,In that case, in the inside of the guide tube, at least a part of the plurality of wires is positioned on the outer side in the width direction of the guide tube so as to correspond to the branch tube close to one of the manholes. In parallel with the width direction of the guide tube,Laying the guide pipe in the main pipe,During the laying, the communication cable drawn from the guide tube is laid in the partial branch pipe,AboveRemainingWhen the communication cable needs to be inserted into the branch pipe, the guide line of the guide pipe is appropriately connected.NewIt is replaced with a communication cable, and the communication cable is drawn from the guide pipe into the branch pipe and laid. According to this method, when it becomes necessary, the communication cable can be drawn into the branch pipe and laid. For this reason, when laying a communication cable in the underground pipe, it is possible to cope with it appropriately even when a home or the like does not want to lay the communication cable at the same time..
[0012]
  The communication cable laying method in the underground conduit according to claim 2 is the method according to claim 1, wherein the communication cable and the communication cable are connected to the guide tube.BeforeCall lineWhen storing the guide tube,BranchtubeEquivalent to mouthFrom the branch hole formed at the position, connect one end of the nominal lineTake it out of the guide tube,SaidWhen the communication cable needs to be inserted into the remaining branch pipes,Removed from the branch holePull out one end of the nominal line to the end of the branch pipe and the other end of the nominal lineNewA communication cable is connected, and one end of the nominal line drawn to the end of the branch pipe is pulled, and the communication cable is laid in the branch pipe through the guide pipe..
[0013]
  A communication cable laying method in the underground pipeline according to claim 3 is the method according to claim 1, wherein the communication cable and the communication cable are connected to the guide tube.BeforeCall lineWhen storing the front of the guide tube,Corresponds to the branch portFrom the branch hole formed at the position, connect one end of the nominal lineTake it out of the guide tube and lay the guide tube in the main tubeWhen removed from the branch holePull out one end of the nominal line to the end of the branch pipeLeave,SaidWhen it becomes necessary to enter the communication cable in the remaining branch pipe,NewA communication cable is connected, one end of the nominal line drawn to the end of the branch pipe is pulled, and the communication cable is laid in the branch pipe through the guide pipe. According to this method, it is not necessary to store the communication cable in the guide tube in advance, and when it is necessary to install the communication cable in each branch pipe, the communication cable is drawn into the guide pipe and installed in the branch pipe. It can respond quickly.
[0015]
  Claim4The communication cable laying method in the underground pipeline as described in claim 2 to3In eitherRemoved from the branch holeSaid nominal lineOne end ofWhen pulling out to the end of the branch pipe,One end ofTo the one end of the main pipe, through the traction measure from the end of the branch pipe to the one end of the main pipe, to connect the nominal line and the traction measure at the one end of the main pipe, Pull the traction measure on the part side to call the nominal lineOne end ofIs pulled to the end of the branch pipe. According to this method, the call wire can be easily pulled out to the end of the branch pipe, and when it is necessary to lay the communication cable, the communication cable can be easily laid in the branch pipe.
[0016]
  Claim5The communication cable laying method in the underground pipeline as described in claim 2Thru 3In eitherRemoved from the branch holeSaid nominal lineOne end of the tube to the end of the branch pipeTo pull out,in frontA caller for hooking or grasping from the end of the branch pipe is provided at one end of the call line. According to this method, one end of the nominal line can be easily grasped or hooked, and the nominal line can be easily pulled out to the end of the branch pipe.
[0017]
  Claim6The communication cable laying method in the underground pipeline described in claim 1 to claim 15In any one of the above, the outer diameter of the communication cable and the outer diameter of the nominal line are substantially equal. According to this method, by keeping the outer diameter of the nominal line and the communication cable substantially the same, there will be no catch when switching from the nominal line to the communication cable, and it will not be switched back and forth in the partition in the guide tube. The communication cable and the call line coming out from the branch hole do not press down the communication cable and the call line located on the back side of the guide tube.
[0018]
  Claim7The communication cable laying method in the underground pipeline described in claim 1 to claim 16In either of the above, after inserting or attaching a low-strength, high-strength tension member to the guide tube and laying the guide tube in the main tube, tension is applied to the tension member in the main tube, The guide tube is laid on the upper side of the cover. According to this method, the tension member can be pulled with the guide tube inserted into the underground tube, and a communication cable, a nominal wire, or the like can be drawn into the guide tube with the guide tube straightened. For this reason, a long communication cable or the like can be drawn.
[0019]
  Claim8The guide tube for laying communication cables in underground conduitsBetween manholesMainMultiple via branch portIn the underground conduit where the branch pipe is branchedFrom the manhole to the branch pipeUsed when laying communication cablesLaid in the mainA guide tube,A branch hole for drawing the communication cable stored in the guide pipe to the outside is formed at a position corresponding to the branch pipe port in a state of being drawn into the main pipe. Smaller than the diameter of the nick that is attached to one end of the nominal wire to replace the cableIt is characterized by this.
[0020]
  Claim9The guide pipe for laying the communication cable in the underground pipeline as described in8InThe guide tube has a width capable of entering a plurality of the communication cables in parallel,At least one partition plate that divides the inside of the guide tube vertically is provided.And the height of the partitioned space is smaller than twice the outer diameter of the communication cable.It is characterized by this. According to this configurationWhen a communication cable or a nominal wire with the same diameter as the communication cable is inserted into the guide tube, it will not cross over the adjacent communication cable, etc. The communication cable will not be cut beyond.
[0021]
  Claim10The guide pipe for laying the communication cable in the underground pipeline as described in8 or 9The guide pipe includes an inner pipe for inserting a main communication cable for laying in the main pipe, and a front pipe.ReportFor laying in a branchSaidIt has a double structure having an outer tube for inserting a communication cable, and the outer tube is, DoubleNumberCommunicationIt has a width that can accommodate a cable. According to this configuration, the communication cable for main pipe having a large diameter and the communication cable having a diameter smaller than that of the communication cable for main pipe can be accommodated in the same guide pipe..
[0022]
  Claim11The guide pipe for laying the communication cable in the underground pipeline as described inIn any one of 8 to 10, the branch hole of the guide pipe is opened at a position shifted from directly below the branch pipe port so that a fluid from the branch pipe does not flow in. .
[0023]
  Claim12The underground cable laying structure of the communication cable as described in is attached to the main pipe provided between the manholes.pluralUnderground pipeline where the branch pipe branchesIn the laying structure of the communication cable laid from the manhole to the branch pipe,Multiple pipes in the mainSaidA guide tube containing communication cables in parallel in the width direction is laid.The communication cable drawn from the guide pipe is laid in the branch pipe, and the guide cables are arranged such that the plurality of communication cables correspond to the branch pipe at a position close to one of the manholes. Parallel to the width direction of the guide tube so as to be located outside the width direction of the tubeIt is characterized by this. According to this structure, the communication cable does not hang inside the underground conduit, so objects passing through the underground conduit are not caught by the communication cable, etc. Will not harm.
[0024]
  Claim13The underground conduit laying structure of the communication cable according to claim 112The guide pipe is installed on the upper side of the main pipe and is connected to the left and right sides of the main pipe in a cross section. The communication cables are connected in parallel so as to correspond to the branch pipes connected to each other. According to this structure, the height of the guide pipe when installed in the main pipe can be suppressed as much as possible due to the structure that allows multiple communication cables to be inserted in parallel in the width direction. If there is a vacant space, it will not interfere with the original function of the underground conduit by installing it at that location.
[0025]
  Claim14The underground conduit laying structure of the communication cable according to claim 112Or13The communication cable is inserted into the guide tube from the vicinity of each manhole, symmetrically at the approximate center of the main tube or the position where the number of the branch tubes is approximately half between the manholes. It is what. According to this structure, when a communication cable is drawn into each branch pipe, a communication cable or the like located on the outer peripheral side of the guide pipe is drawn, and communication located on the back side of the guide pipe as it moves away from one manhole. The cable can be pulled out. For this reason, when laying a communication cable in each branch pipe, the communication cables can be pulled out of the guide pipe without being caught in the guide pipe.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the underground pipeline is described as a sewer pipe. However, the present invention does not directly attach a jig such as a hook to the inner surface of the underground pipeline. There are no restrictions. For example, the present invention can be applied to all underground pipelines such as gas pipelines piped with steel pipes, water pipes piped with cast iron pipes, rainwater pipes, and power cable pipes. Further, when no manhole is provided in the above-described pipe line, it is possible to form the resist and implement the present invention.
[0027]
FIG. 1 shows an underground conduit 1 provided between manholes 2 and 3 for laying communication cables. Other manholes may be provided between the manholes 2 and 3, and the present invention can be similarly applied even if the manhole is a communication base. In FIG. 1, a plurality of branch pipes A, B,... J corresponding to households a, b,.
[0028]
FIG. 2 shows a cross-sectional view taken along the line II of FIG. In FIG. 2, reference numeral 1 denotes a main sewer pipe, which is piped between a manhole 2 and another manhole 3. From the upper side of the main pipe 1, branch pipes 4 and 5 (corresponding to any of A to J in FIG. 1) branch at branch pipe ports 6 and 7, and the branch pipes 4 and 5 are connected to each household (see FIG. 1) (corresponding to a, b,... J in FIG. 1).
[0029]
In general, the main pipe 1 is laid at a depth of several meters along the road. As shown in FIG. 3, branch pipe ports 6 and 7 are formed on the oblique upper side of the main pipe 1, and the branch pipe 4, After rising from the branch pipe ports 6 and 7 at a steep angle, 5 changes the angle near the ground surface and is connected to the branch pipe rods 8 and 9 at a gentle angle.
[0030]
As shown in FIG. 1, the underground pipe in the present embodiment includes branch pipes A to J from the main pipe 1, a, b, c, d, e on the upper side of the figure, f on the lower side of the figure, There are a total of 10 branches toward each home located at g, h, i, j. In this embodiment, communication cables are laid only in three houses located at b, e, and j, and other houses located at a, c, d, f, g, h, and i. A description will be given assuming that no communication cable is installed.
[0031]
First, using a TV camera or the like in the main pipe 1, the distance between the manholes 2 and 3, the distance from the manhole 2 to the branch ports 6 and 7 of the branch pipes 4 and 5 in the main pipe 1, the branch pipe 4 , 5 to the branch pipe rods 8 and 9 and the depth of the branch rods 8 and 9 are accurately measured (see FIG. 2). After conducting the survey as described above, a guide tube for storing the communication cable is prepared.
[0032]
Here, in the present embodiment, a plastic tube, which will be described later, can be easily laid in the future for houses a, c, d, f, g, h, and i where no communication cable is laid. A nominal line made of rope or rope is laid near each branch pipe port of the main pipe 1 or to each branch rod.
[0033]
An example of the guide tube 11 used in the present invention is shown in FIG. The shape of the guide tube shown in FIG. 4 is particularly suitable in the present invention. The guide tube 11 is preferably made of a resin such as polyethylene because of its light weight and chemical resistance, but other materials can be selected depending on the type of underground conduit.
[0034]
As shown in FIG. 4, the guide tube 11 is a double-structured pipe composed of an outer tube 12 and an inner tube 14 having a partition plate 13 extending left and right. The inside of the inner pipe 14 serves as a passage for passing a trunk line of a communication cable passing through the main pipe 1 or a trunk line for the trunk line. Two partition plates 13 a, 13 b, 13 c, and 13 d that extend to the left and right are attached to both sides of the outer periphery of the inner tube 14, and partition the space between the outer tube 12 and the inner tube 14 in the vertical direction. The outer tube 12 is a hollow tube having a substantially elliptical cross section so that a plurality of communication cables or call wires can be arranged in parallel.
[0035]
Six spaces 15a, 15b, 15c, 15d, 15e, and 15f surrounded by the partition plates 13a, 13b, 13c, and 13d serve as passages for passing the communication cable 16 or the call wire 17. In addition, it is preferable to use the thing with the thickness with which communication cable 16 and nominal line 17 are substantially equal. Thus, when the call line 17 and the communication cable 16 are exchanged, the communication cable 16 is not displaced. Further, since an excessive pulling force does not act when the communication cable 16 is pulled, disconnection of the communication cable 16 can be prevented. As the communication cable 16, a four-core optical fiber is passed through a stainless steel tube, and a cable having a thickness of about 5 mm whose outer surface is coated with polyethylene can be suitably used in this embodiment. Moreover, as the nominal line 17, a urethane tube having an outer diameter substantially equal to the outer diameter of the communication cable 16 can be suitably used. Here, in the present embodiment example, the connection method of the communication cable 16 and the call wire 17 may be crimped with a metal ring or the like, but the material of the communication cable coating and the call wire is made of plastic, If the nominal line is tube-shaped, insert the tip of the communication cable into the nominal line for an appropriate length to form an overlapping part, and then crimp the outer part by thermocompression or dielectric to melt the overlapping plastic. However, it can be crushed and formed into a shape with almost no step. The communication cable 16 can be a two-core type or other types in addition to the four-core type.
[0036]
The height of each passage 15 of the communication cable 16 and the call wire 17 that is partitioned by the partition plate 13 of the space 15 of the outer tube 12 and the inner tube 14 of the guide tube 11 is 2 of the outer diameter of the communication cable 16 and the call wire 17. It is lower than twice. By adopting such dimensions, the communication cable 16 or the call wire 17 having substantially the same diameter as the communication cable 16 does not cross over the adjacent communication cable when entering the guide tube 11, The communication cable will not be entangled inside the guide tube and excessive tension will be applied, or the communication cable will not be cut beyond the allowable bending radius. In addition, the structure in which a plurality of communication cables 16 can be connected in parallel in the width direction can suppress the height when installed in the main pipe 1 as much as possible. For example, an empty space in the upper part such as a sewer pipe or a rainwater pipe. If there is, there is no hindrance to the original function of the underground conduit by installing it at that location.
[0037]
As shown in FIG. 4, the communication cable 16 is connected to the guide tube 11 at a position about 1 m from the position at each of the branch pipe ports 6 and 7 with the guide tube 11 being drawn into the main tube 1. A branch hole 18 is provided for drawing the nominal line 17 from the guide tube 11 to the outside. The branch holes 18 are opened on both side surfaces of the guide tube 11 at positions corresponding to the length from the manhole 2 to each branch tube port (within a range of about 1 m in the front and rear directions) with one end of the guide tube 11 as a base point. ing. The branch hole 18 is preferably formed in advance in a factory or the like based on the investigation result in the underground pipeline.
[0038]
The communication cable 16 and / or the call line 17 taken out from the branch hole 18 has a distance of 1 m from one end of the main pipe 1 connected to the manhole 2 to the branch pipe port of the branch pipe A in FIG. If there is, the branch hole 18 is also opened at a position of about 1 m from one end of the guide pipe 11, and the branch pipe communication cable 16 and the call line 17 are taken out from the branch hole 18. In this case, since the fluid from the branch pipe may flow into the branch hole 18 at the position of the branch hole 18, it is preferable to avoid a position immediately below the branch pipe opening.
[0039]
At the tips of the communication cable 16 and the call wire 17 taken out from the branch hole 18, members 19 and 20 used when pulling the communication cable from the guide tube are attached so as not to be removable. Various shapes such as a hook shape and a ring shape can be adopted as the shapes of the callers 19 and 20, but at least the outer diameter of the callers 19 and 20 is larger than the size of the branch hole 18, and the outside of the guide tube 11. It is important that the tip of the communication cable 16 and the like taken out is not returned to the inside of the guide tube 11. In FIG. 4, the caller 19 has a spherical shape with a diameter of about 100 mm in which wires having a thickness of about 1 mm are combined in a hand shape. The caller 20 is a resin ball having a diameter of about 20 mm, such as a ping-pong ball. Of course, the communication cable 16 may be processed into a shape that can be directly hooked or grasped.
[0040]
When the caller 19 is connected to the communication cable 16, the communication cable 16 is pulled out from the guide pipe 11 to some extent, and is hooked or grasped from the branch pipe ports 6 and 7. It is preferable to facilitate. When the caller 20 is connected to the call wire 17, the position of the caller 20 is left until the time when the communication cable 16 needs to be inserted, so that the caller 20 contacts the branch hole 18. It is preferable to keep the plunger 20 from jumping out of the guide tube 11 by pulling it up to the extent that it does not obstruct the flow in the underground conduit as much as possible.
[0041]
Further, in the present embodiment, as described below, the communication cable 16, the communication cables 16, the call wires 17, or the communication cables 16 and the call wires 17 are not entangled in the guide tube 11. And the place where the nominal line 17 enters the guide pipe 11 is regularly related to the formation of branch pipes A to J extending from the main pipe 1 to each home located at a, b,. It is arranged according to the law of incoming lines.
[0042]
In FIG. 5A, a communication cable 16 and / or a call line 17 with symbols “a” to “j” is inserted in the guide tube 11. A top view thereof is shown in FIG. The incoming state of the communication cable 16 and the like in the guide tube 11 is the same as the piping shape of the underground conduit shown in FIG. Specifically, in the main pipe 1 of the underground conduit in FIG. 1, the number of branch pipes is 10 from A to J, and the communication cable 16 is laid only in three houses of b, e, and j. In other words, when a communication cable is laid in the branch pipes 4, 5, and 10, the communication cable 16 is inserted into the portions corresponding to b, e, and j in the guide pipe 11 in FIG. A call line 17 is inserted into a, c, d, f, g, h, i. Then, as shown in FIG. 5 (b), the communication cable 16 and the call wire 17 are taken out from the guide pipe 11 at portions corresponding to the respective branch pipe ports, and callers 19 and 20 are respectively formed at the tips thereof. It is. In the drawing, the blackened portion shows the tension member 21, and the lowermost spaces 15e and 15d defined by the inner tube 14 and the partition plate 13 of the guide tube 11 have about 1 to 2 mm of wire, tegs, or monofilament yarn. A thin line 22 such as is connected. The tension member 21 and the thin wire 22 are connected to the entire length of the guide tube 11. In FIG. 5B, the callers 19 and 20, the tension member 21, the thin wire 22 and the like are omitted. The tension member 21 has a long length of rope, string, belt, etc. made of high-strength low-stretch fibers such as polyparaphenylene benzohistoxazole (PBO) fiber, aramid fiber, carbon fiber, metal fiber, and glass fiber. Body, stainless wire, etc. can be used.
[0043]
Thus, the regular entry law in the guide tube means that the communication cable 16 and the like are arranged in the guide tube 11 in parallel in the width direction, and the communication cable 16 and / or the reference line 17 (see FIG. 5) a) is inserted into a branch pipe (A in FIG. 1) located closest to one manhole 2 (see FIG. 2), and is sequentially connected toward the inside of the main pipe. That is, the communication cable 16 or the like (b in FIG. 5) located on the outer side next to the outermost side is arranged on the pipe so that it can be inserted.
[0044]
When the branch pipes are connected to the left and right in the cross section of the main pipe 1 as in the underground pipeline of FIG. 1, the communication cables in the guide pipe are arranged in parallel in the width direction. From the left and right outermost sides, the manholes 2 are arranged so that they can enter the branch pipes on the left and right nearest sides of one manhole 2.
[0045]
As the role of the thin wire 22, the one in the inner tube 14 is used for inserting a main communication cable. Usually, the main communication cable has a large diameter and is highly rigid, and if it is pre-wired in the guide tube, it is difficult to wind it around the reel drum, and the core diameter of the reel drum needs to be increased. It is expected that there will be more incoming lines at the site. On the other hand, the thin line 22 in the lowermost partition spaces 15e and 15d serves as a call line for entering the branch pipe when a new house is constructed in the future and a new branch pipe is connected to the main pipe. To do. In this case, when the branch pipe is newly installed, the branch hole 18 is opened in the guide pipe 11 at a position corresponding to the branch pipe ports 6 and 7 (see FIG. 2), and the thin wire 22 is drawn from there to communicate the communication cable 16 and / or the nominal line. Replace with 17.
[0046]
In addition, there is no problem even if the call wire 17 having the same diameter as the communication cable 16 is inserted from the beginning instead of the thin wire 22. Further, when replacing the thin wire 22 with the communication cable 16, it may be carried out after making it easy to transmit the take-up force by interposing a traction measure having an intermediate diameter between the fine wire and the communication cable without connecting directly. good.
[0047]
Next, a method for laying the guide tube 11 with the communication cable 16 and the like inserted therein as described above will be described.
[0048]
The guide tube 11 into which the communication cable 16 or the like is inserted is wound around a reel drum or the like and carried into the construction site. As shown in FIG. 2, at the construction site, the traction measure 23 previously connected between the manholes 2 and 3 and one end portion of the guide tube 11 are connected to one end portion of the main tube 1 by, for example, the manhole 2, and the traction measure Is taken from the other manhole 3 and a guide tube is arranged in the main tube 1. Here, as a method of passing the traction measure 23 between the manholes 2 and 3, there are a method of pushing a rigid body such as a wire, a method of flying a parachute-like connecting tool with air pressure, and a self-propelled in-pipe mobile vehicle. Are known, and these known methods can be appropriately employed. It should be noted that a resistance is dug for a pipe or the like where a manhole is not provided in a section where a communication cable is laid, and this is used as a human hole. Further, when the guide tube 11 is pulled from one manhole 2 to the other manhole 3, in order to prevent the guide tube from being twisted, a twist prevention tool such as a return is interposed between the traction measure and the guide tube 11. You may let them.
[0049]
After arranging the entire length of the guide tube 11 in the main tube 1, the twist prevention tool is removed. At this stage, the respective branch holes 18 provided in the guide pipe 11 are substantially aligned with the respective branch pipe ports 6 and 7. Next, the communication cable 16 and / or the call line is laid in the branch pipes A to J. At this time, like the main pipe 1, the traction measures 24 and 25 are passed through the main pipe 1 from the branch pipes A to J through the main pipe to one end, for example, the manhole 2, and the guide pipe 11 is inserted. Sometimes, the communication cable 16 and the call wire 17 may be laid from the end of the branch pipe in connection with the traction measures 24 and 25. Further, arm-shaped gripping jigs or the like are inserted from the branch pipes A to J, and the communication cables 16 located near the branch pipe ports 6 and 7 and callers 19 and 20 provided at one ends of the call wires 17 are provided. You may hold it and pull it out to each branch ridge 8,9 and lay it. In this case, the guide pipe may be finely adjusted back and forth within the main pipe to assist the installation work of the branch pipe communication cable and the like.
[0050]
Moreover, in this embodiment, in the underground pipeline, especially in a pipeline where sewage flows in the lower part of the main pipe 1 such as a sewer or a rainwater pipe, the original function of the underground pipeline is not impaired. The guide tube 11 is preferably installed on the upper side of the main tube 1 and the branch tube as shown in FIG.
[0051]
As a fixing method to the main pipe 1 and the upper part of the branch pipe, for example, it is preferable to use a guide member 30 as shown in FIG. 7 for each of the branch pipes A to J. The guide member 30 has an outer diameter substantially corresponding to the inner diameter of the branch pipes 4 and 5, and has a cylindrical insertion portion 33 having a cross section of a semicircle or more, and continuously protrudes downward and outward from the cylindrical insertion portion 33. A slide part 31 that slidably holds a guide pipe 11 laid in the main pipe 1, and a communication cable 16 or a call line 17 laid in the branch pipes 4 and 5 provided in the insertion part 33 can be slid. It is comprised with the branch slide part 32 hold | maintained.
[0052]
When the guide member 30 is used, when the callers 19 and 20 are pulled to the branch rods 8 and 9, they are passed through the branch slide portion 32. In this case, it is preferable to pass the communication cable 16 or the call wire 17 through the branch slide portion 32 in advance and form the callers 19 and 20 before forming the callers 19 and 20 in a factory or the like. This improves work efficiency at the construction site. As a specific work procedure, first, a TV camera is inserted from the branch rods 8 and 9, and it is confirmed whether the guide member 30 is located near the branch pipe ports 6 and 7.
[0053]
In addition, when each guide member 30 moves in the main pipe 1, if there is a risk that the guide member 30 may be damaged by friction with the pipe inner wall or caught on a step in the pipe line, the carriage that can move in the main pipe 1. It is preferable to place it on a simple ship and pull it in at the same time as the towing plan.
[0054]
Next, an arm-shaped gripping jig or the like is inserted from the branch rod 8, and the callers 19 and 20 are grasped and taken out from the branch rod 8 while checking with a TV camera or the like. At this time, the guide tube 11 in the main tube 1 is moved to finely adjust the callers 19 and 20 to positions where they can be easily grasped.
[0055]
Next, the communication cable 16 or the call wire 17 is pulled by the branch rod 8 and the leading end portion of the guide member 30 is inserted into the branch pipe port 6. If the direction of the leading end of the guide member 30 does not change even after the communication cable 16 or the call wire 17 is pulled, the air packer is contracted and inserted into the branch pipe port 6 from the branch rod 8 to the inner surface of the guide member 30. It is preferable to insert and inflate, take the air injection part, and change the direction of the tip of the guide member 30 to the direction of the branch pipe 4. As a method for fixing the branch pipe port 6 of the guide member 30, adhesive or adhesive is applied in advance to the outer surface of the columnar insertion portion 33 of the guide member 30, and fixed by contact with the inner surface of the branch pipe 4. Alternatively, an elastic body such as rubber or sponge may be provided on the outer surface of the cylindrical insertion portion 33, or a tapered tapered surface may be formed and fixed by frictional pressure bonding.
[0056]
Further, the guide member 30 having a shape as shown in FIG. 8 can be used. When such a guide member 30 is used, the cylindrical fixing portion 41 is reduced in diameter by a thin line or the like, inserted into the branch pipe 4, and then the thin wire is cut to release the reduced diameter to expand the cylindrical fixing portion 41. The cylindrical fixing portion 41 is fixed in the branch pipe 4. In this case, as in the case of the guide member 30 having the shape shown in FIG. 7 described above, an adhesive or an adhesive is applied in advance to the outer surface of the columnar fixing portion 41 and fixed by contact with the inner surface of the branch pipe 4. Alternatively, an elastic body such as rubber or sponge may be applied to the outer surface of the cylindrical fixing portion 41, or a tapered tapered surface 42 may be formed and fixed by frictional pressure bonding.
[0057]
In the other branch pipes 5, the same operation is sequentially performed, the communication cable 16 or the call wire 17 is taken out from the branch rod 9, and the guide member 30 is inserted and fixed in the branch pipe port 7.
[0058]
Next, the tension member 21 housed in the guide tube 11 is fixed to the hook on one side by using a tension mechanism 34 attached to the manholes 2 and 3, for example, a drum-type retractable manual winch and a hook. On the other hand, tension is applied with a winch, and the guide tube 11 is laid on the upper side in the main tube 1.
[0059]
Here, when the branch pipe 4 is a straight pipe, by applying tension with the tension mechanism 34 attached to the branch pipe rods 8 and 9 as it is, the communication cable 16 or the call line 17 is placed on the upper part of the branch pipes 4 and 5. Can be laid.
[0060]
However, for example, when the branch pipes 4 and 5 are curved pipes as shown in FIG. 6, simply applying tension with the tension mechanism 34 attached to the branch pipe rods 8 and 9, the bent pipes 4 and 5 are bent. The communication cable 16 or the call wire 17 cannot be laid along the upper part of the inner surface of the valley portion 26. Therefore, in this case, for example, a fixing member B as shown in FIG. 9 is arranged along the upper portion of the inner surface of the valley portion 11 in the valley portion 26 of the curved pipe of the branch pipes 4 and 5.
[0061]
As for the arrangement method, the cylindrical fixing portion 43 is reduced in diameter and moved to the vicinity of the curved pipe portion while the tension member 21 and the communication cable 16 reaching the branch rod 8 are passed through the slide portion 44 of the fixing member 45. . As the moving means, a method of attaching to the outside of the air packer described above or a dedicated device may be used. If the slide part 44 is arranged on the inner surface upper part of the trough part 26 of the curved pipe, the columnar fixing part 43 is fixed in the branch pipes 4 and 5 as in the case of the guide member 30.
[0062]
As described above, the guide tube 11, the communication cable 16, and the call wire 17 can be laid on the upper side of the main tube 1 and the branch tubes A to J. This process may be performed either before or after the laying of the communication cable for the branch pipe, and the tentative tension is applied to the tension member at the time of laying the communication cable or the like so that the guide pipe is substantially suspended. Also good.
[0063]
10 is not a method of applying tension by the above-described tension mechanism 34 or the like. For example, a plurality of sagging prevention materials 50 shown in FIG. 10 are arranged in the main pipe 1 as shown in FIG. 11 may be supported. The method for moving and fixing the sagging prevention material 50 is fixed by the columnar fixing portion 51 as in the case of the fixing member 45 and the guide member 30.
[0064]
When laying the guide tube 11 by skipping several manholes, the guide tube is curved along the inner wall of the manhole as shown in FIG. 12 (or refracted if rectangular). It is preferable to connect by the member 27 and avoid the main 1 extension line. The guide pipe connecting member 27 may be a half pipe, and the guide pipe 11 in the manhole is removed, and the communication cable 16 and the tension member 21 are bent along the side wall of the manhole.
[0065]
As described above, the communication cable 16 is connected to the branch pipes B, E, and J that connect to the homes b, e, and j where it is desired to install the communication cable 16 in the main pipe 1 and the guide pipe 11 this time. A call line 17 can be laid for a home that is laid and does not wish to lay the communication cable 16 at the time of the other laying of a, c, d, f, g, h, i. In the future, when one of the households a, c, d, f, g, h, i that wishes to install the communication cable 16 appears, each branch pipe A, C, D, F, G, H The communication cable 16 can be laid by replacing the call line 17 laid up to the branch pipe port of the I, I or the branch ridge which is the branch end.
[0066]
When replacing the communication cable 16, the communication cable 16 is connected to one end of a call line 17 laid on a branch pipe of a home that is desired to be newly laid on the manhole 2 side. The connection method of the communication cable 16 and the call wire 17 may be crimped with a metal ring or the like, or if the material of the communication cable coating and the call wire is made of plastic and the call wire is a tube, the call Insert the appropriate length of the communication cable into the inside of the wire to form an overlapping part, and crimp the part from the outer surface by thermocompression or dielectric, and crush while melting the plastic of the overlapping part. It is also possible to do. After connecting the communication cable 16 and the call line 17 on the manhole 2 side, the communication cable 16 can be drawn into the guide pipe 11 by being pulled from the branch pipe side, and laid in the branch pipe. be able to.
[0067]
When a new branch pipe is newly installed, the communication cable 16 or the like is connected to one end side of the thin wire 22 stored in the guide pipe 11 or the nominal line 17 stored as a spare as described above. Therefore, it is possible to cope with the problem by replacing the thin line 22 or the call line 17.
[0068]
As described above, when the communication cable 16 needs to be laid, the communication cable 16 can be laid easily and appropriately. For this reason, it is possible to lay a communication cable at a workability comparable to that of the aerial method and the construction cost. In addition, the original function of the underground conduit is not hindered, it does not adversely affect the maintenance work of the underground conduit, and the communication cable is not damaged during the original use or maintenance of the underground conduit. Communication cables can be installed.
[0069]
Note that the guide pipe for laying a communication cable in the underground conduit according to the present invention is not limited to that according to the above-described embodiment, and may have the structure shown in FIGS. 13 to 15. It is.
[0070]
FIG. 13A shows a pipe-like object having a width that allows a plurality of communication cables to be inserted and having an internal height smaller than twice the outer diameter of the communication cable 16. By adopting such dimensions, the communication cable 16 or the call wire 17 having the same diameter as that of the communication cable does not cross over the adjacent communication cable 16 when entering the guide tube 11, and the guide The communication cable 16 is not entangled inside the tube 11 and unreasonable tension is applied, and the communication cable 16 does not exceed the allowable bending radius. In addition, a structure that allows multiple communication cables 16 or the like to be inserted in parallel in the width direction can suppress the height when installed in the main as much as possible, so that there is an empty space in the upper part, such as a sewer pipe or a rainwater pipe, for example. In some cases, the original function of the underground conduit is not hindered by being installed at that location. In FIG. 13B, a partition plate that is vertically divided is provided inside the guide tube 11, and its internal height is the same as that in FIG. 13A. FIG. 13C is a diagram in which a partition plate 13 that is divided into left and right is provided at the approximate center of the guide tube 11 in FIG. 13D has the same structure as FIG. 13C, but the inner partition plate 13 is a separate object and the outer tube of the guide tube 11 is formed. FIG. 13 (e) shows an inner pipe 14 that accommodates the communication cable 28 (or call line) for the main pipe 1 provided in the approximate center of the guide pipe 11 in FIG. 13 (c).
[0071]
FIG. 14A shows a simple pipe shape, in which as many communication cables as possible are accommodated. FIG. 14 (b) shows an example in which a partition plate for dividing the communication cable 16 into a plurality of parts is provided in the guide tube 11 of FIG. 14 (a). In addition, a low-elongation high-strength tension member 21 (black portion) made of a wire or high-strength fiber for installing the guide tube 11 on the upper portion of the main tube 1 is inserted in the central portion. Similarly, FIG. 14C shows the tension member 21 formed at the upper part of the partition plate 13. In FIG. 14D, a branch pipe communication cable 16 and the like are partitioned by a partition plate 13 which is divided into left and right, and a main communication cable 28 is accommodated in the center. A space for passing the tension member 21 is also formed on both sides. Furthermore, in order to accommodate the communication cable 16 and the like in the guide tube 11, the upper part is a lid and is fitted and integrated.
[0072]
As a method of inserting the communication cable 16 and / or the call line 17 into the guide tube 11 as described above, the necessary number of thin thread-like traction measures are passed through the guide tube 11 in advance, and the communication cable 16 and / or There are a method in which the guide wire 11 is connected and pulled in, and a method in which the guide tube 11 is crafted as shown in FIG. Specifically, as shown in FIG. 15A, the guide tube 11 is divided into upper and lower portions 60 and 61, and an uneven portion 63 is provided on the contact surface of the divided piece so as to be fitted. Accordingly, the communication cable 16 or the like is inserted with the upper divided piece 61 removed. As the shape of the divided pieces 61 and 62, the lid shape shown in FIG. In addition, as shown in FIG. 15B, a cut 64 can be formed for each space formed by the partition plate on the outer peripheral surface of the guide tube 11. A communication cable 16 or the like or a towing measure for wiring is inserted from the notch 65. It is also possible to fit an I-shaped member (not shown) such as a rail after entry into the notch 64. By doing in this way, especially with respect to the cut of the upper surface, it is preferable because dew condensation in the underground conduit and fluid from the branch pipe can be prevented from entering and staying in the guide pipe 11. 15 (c) and 15 (d) show an example of an incoming line method when the partition plate 13 is divided, and the communication cable is previously connected to the partition plate 13 as shown in FIG. 15 (d). 16 or the like is installed, the tape-like material is fixed at an appropriate interval, and it is inserted into the pipe 66 shown in FIG. 15 (c). When using the tension member 21, it may be installed in any part of the guide tube 11 described so far. However, when using a plurality of the tension members 21, the height of the guide member is parallel to the height of the guide tube. It is preferable to connect the wires in parallel. There is no limitation on the number, and the number may be appropriately determined depending on the installation length and the total weight of the guide tube. Further, a structure in which the tension member 21 is integrated with the guide tube 11 may be used, or a structure in which the tension member 21 is integrated with a partition plate as shown in FIGS.
[0073]
In the above-described example of the embodiment according to the present invention, the guide tube 11 has been described as an integral unit according to the length of the manholes 2 and 3. When laying the communication cable 16 or the like in a crowded area or the like, for example, a plurality of guide tubes 11 can be joined and used as shown in FIG.
[0074]
In FIG. 16, a guide tube 11 is formed by joining two guide tubes at the center, and FIG. 16 (a) shows a cross-sectional view as viewed from the right end of the guide tube 11, and FIG. A top view of the tube 11 is shown. In FIG. 16B, the cross-sectional view seen from the left end side of the guide tube 11 corresponds to FIG. And the incoming position of the communication cable 16 etc. in the guide tube 11 is symmetrical at a position that is approximately half the number of branch pipes to which the guide tube 11 corresponds, and the symmetrical communication cable 16 etc. is in each manhole. The guide pipes 11 are arranged in parallel in the width direction of the guide pipes 11 one after another in the vicinity of the branch pipes. As a result, even when the distance between the manholes becomes long, it is possible to cope with the problem by joining the two guide tubes 11 and arranging them in parallel in order from the closest to each manhole. The guide tube 11 may be a long one.
[0075]
【The invention's effect】
According to the first aspect of the present invention, when it becomes necessary, the communication cable can be drawn into the branch pipe and laid. For this reason, when laying a communication cable in the underground pipe, it is possible to appropriately cope with a case where a household or the like does not want to lay a communication cable at the same time. For this reason, it is possible to lay a communication cable at a workability comparable to that of the aerial method and the construction cost. In addition, the original function of the underground conduit is not hindered, it does not adversely affect the maintenance work of the underground conduit, and the communication cable is not damaged during the original use or maintenance of the underground conduit. Communication cables can be installed.
[0076]
  Claims 2 to3According to the invention, it is not necessary to store the communication cable in the guide tube in advance, and when it is necessary to install the communication cable in each branch tube, the communication cable is drawn into the guide tube and installed in the branch tube. Can do.
[0077]
According to the invention of claim 3, it is not necessary to store the communication cable in the guide tube in advance, and when it is necessary to lay the communication cable in each branch tube, the communication cable is drawn into the guide tube and into the branch tube. Can respond quickly to laying.
[0079]
  Claim4According to this invention, the call wire can be easily pulled out to the end of the branch pipe, and when it is necessary to lay the communication cable, the communication cable can be easily laid in the branch pipe.
[0080]
  Claim5According to the invention, one end of the nominal line can be easily grasped or hooked, and the nominal line can be easily pulled out to the end of the branch pipe.
[0081]
  Claim6According to the invention, by keeping the outer diameters of the nominal line and the communication cable substantially equal, there is no catching on the exchange from the nominal line to the communication cable, and the front and rear are not interchanged in the partition in the guide tube. The communication cable and the call line coming out from the branch hole do not press down the communication cable and the call line located on the back side of the guide tube. For this reason, communication cables or the like are not entangled in the guide tube, and the communication cables or the like can be pulled out lightly.
[0082]
  Claim7According to this invention, the tension member is pulled in a state where the guide tube is inserted into the underground tube, and the communication cable, the nominal wire, etc. can be drawn into the guide tube in a state where the guide tube is straightened. For this reason, a long communication cable or the like can be drawn.
[0083]
  Claim9According to the invention, when a communication cable or a nominal wire having the same diameter as the communication cable is inserted into the guide tube, it does not cross over the adjacent communication cable, etc., and is entangled inside the guide tube and an excessive tension is applied. Or the communication cable does not cut beyond the allowable bending radius.
[0085]
  Claim10According to this invention, the communication cable for main pipes with a large diameter and the communication cable for branch pipes with a smaller diameter compared with the communication cable for main pipes can be accommodated in the same guide pipe.
[0087]
  Claim12According to the invention, since the communication cable does not hang down in the underground conduit, the object passing through the underground conduit is not caught by the communication cable, etc., and the original function of the underground conduit Will not be damaged.
[0088]
  Claim13According to the invention, the height of the guide pipe when it is installed in the main pipe can be suppressed as much as possible by the structure that allows a plurality of communication cables to be inserted in parallel in the width direction. If there is a vacant space, it will not interfere with the original function of the underground conduit by installing it at that location.
[0089]
  Claim14According to the invention, when the communication cable is drawn into each branch pipe, the communication cable or the like located on the outer peripheral side of the guide pipe is drawn, and the communication located on the back side of the guide pipe as the distance from one manhole increases. The cable can be pulled out. For this reason, when laying a communication cable in each branch pipe, the communication cables can be pulled out of the guide pipe without being caught in the guide pipe.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing an example of an arrangement of underground conduits according to the present invention.
2 is a cross-sectional view taken along line II in FIG. 1. FIG.
FIG. 3 is a cross-sectional view showing an arrangement state of branch pipes.
FIG. 4 is a cross-sectional perspective view of an embodiment of a guide tube for laying a communication cable in an underground conduit according to the present invention.
FIG. 5 is a diagram for explaining an example of a method for wiring a communication cable or the like into a guide tube. (A) is sectional drawing, (b) shows a top view.
FIG. 6 is a cross-sectional view showing a state in which a guide pipe, a communication cable, and the like are laid in the underground pipeline.
FIG. 7 is a perspective view showing an embodiment of a guide member used when a communication cable or the like is laid on the upper side in the underground conduit.
FIG. 8 is a perspective view showing another embodiment of the guide member.
FIG. 9 is a perspective view showing an embodiment of a fixing member for laying a communication cable or the like on the upper side in a branch pipe.
FIG. 10 is a perspective view showing an embodiment of a sagging prevention material for preventing sagging of a guide pipe or the like in the main pipe.
FIG. 11 is a diagram showing an example of a state when a guide pipe is installed on the upper side of the main pipe.
FIG. 12 is a perspective view showing an embodiment of a guide pipe connecting member used when laying a guide pipe by skipping some manholes during laying.
FIG. 13 is a cross-sectional view showing another embodiment of the guide tube.
FIG. 14 is a cross-sectional view showing another embodiment of the guide tube.
FIG. 15 is a diagram for explaining a method of inserting a communication cable or the like into the guide tube.
FIG. 16 is a diagram showing an example of an embodiment in which guide tubes are joined when the distance between manholes is long.
[Explanation of symbols]
1 Main
2 Manhole
3 Manhole
4,5 branch pipe
6,7 Branch port
8,9 Branch pipe
11 Guide tube
12 Outer pipe
13 Partition plate
14 Inner pipe
15 space
16 Communication cable
17 Call line
18 Branch hole
19, 20
21 Tension member
22 Fine wire
23, 24, 25
26 Tanibe
27 Guide pipe connecting member
28 Mains communication cable
30 Guide member
31 Slide part
32 Branch slide part
33 Insertion section
34 Tension mechanism
41 Cylindrical fixing part
42 Tapered surface
43 Cylinder fixing part
44 Slide part
45 Fixing member
50 Sagging prevention material
51 Cylinder fixing part

Claims (14)

In the underground pipe where a plurality of branch pipes branch to the main pipe provided between the manholes via a branch pipe port, a communication cable is laid from the manhole to the branch pipe ,
A communication cable for laying on a part of the branch pipe of the plurality of branch pipes, later consisting of the remainder of the branch pipe call line for laying communication cables, housed in advance the guide tube a plurality of streak And
In that case, in the inside of the guide tube, at least a part of the plurality of wires is positioned on the outer side in the width direction of the guide tube so as to correspond to the branch tube close to one of the manholes. In parallel with the width direction of the guide tube,
The guide pipe is laid in the main pipe, and at the time of laying, the communication cable drawn from the guide pipe is laid in the partial branch pipe,
When it is necessary to enter the communication cable into the remaining branch pipe, the guide line of the guide pipe is appropriately replaced with a new communication cable, and the communication cable is drawn into the branch pipe from the guide pipe. A method of laying a communication cable in an underground conduit characterized by laying. The guide tube, when receiving the communication cable及beauty before SL called lines, the guide tube, from said branch hole formed at a position corresponding to the branch pipe opening, said guide tube one end of the call line Take it out,
When the communication cable needs to be inserted into the remaining branch pipe, one end of the nominal line taken out from the branch hole is pulled out to the end of the branch pipe, and a new one is added to the other end of the nominal line. The communication cable is connected, the one end of the nominal line drawn to the end of the branch pipe is pulled, and the communication cable is laid in the branch pipe through the guide pipe. A method for laying communication cables in underground conduits. The guide tube, when receiving the communication cable及beauty before SL called lines, wherein the guide tube, before Symbol position the formed branch hole corresponding to the branch pipe opening, said one end of the call line guide Take it out of the tube,
When laying the guide pipe in the main pipe, one end of the nominal line taken out from the branch hole is pulled out to the end of the branch pipe,
When the communication cable needs to be inserted into the remaining branch pipe, a new communication cable is connected to the other end of the call line, and one end of the call line pulled out to the end of the branch pipe is connected. 2. The method of laying a communication cable in an underground conduit according to claim 1, wherein the communication cable is pulled and laid in the branch pipe through the guide pipe. When pulling out one end of the nominal line taken out from the branch hole to the branch pipe end , one end of the nominal line is taken out to the main pipe one end and pulled from the branch pipe end to the main pipe one end. Connecting the nominal line and the traction measure at one end of the main pipe, and pulling the traction measure on the branch pipe end side to pull one end of the nominal line to the branch pipe end. A method for laying a communication cable in an underground conduit according to any one of claims 2 to 3 . To bring out the end of the call lines taken out from the branch hole to the branch pipe end, to one end of the prior SL called lines, or hooking from the branch pipe end, providing the whistle to grab A method for laying a communication cable in an underground conduit according to any one of claims 2 to 3 . The method for laying a communication cable in an underground conduit according to any one of claims 1 to 5 , wherein an outer diameter of the communication cable is substantially equal to an outer diameter of the nominal line. A tension member having a low elongation and high strength is inserted into or attached to the guide pipe, and the guide pipe is laid in the main pipe, and then tension is applied to the tension member in the main pipe, and the upper side in the main pipe A method for laying a communication cable in an underground conduit according to any one of claims 1 to 6, wherein a guide tube is laid. In underground conduit to the main pipe provided between the manhole via the branch pipe opening is a plurality of branch pipes are branched, used when laying communication cables from the manhole to the branch pipe, the present pipe A guide tube laid on
A branch hole is formed in the position corresponding to the branch pipe port in a state of being drawn into the main pipe, and the communication cable housed in the guide pipe is drawn out to the outside.
A guide pipe for laying a communication cable in an underground conduit, characterized in that the diameter of the branch hole is smaller than the diameter of a caller attached to one end of a call line for replacing the communication cable. The guide tube has a width capable of entering a plurality of the communication cables in parallel,
At least one partition plate that divides the guide tube into upper and lower portions is provided , and a height of the partitioned space is smaller than twice an outer diameter of the communication cable. Item 9. A guide tube for laying a communication cable in the underground conduit according to Item 8 . Two with the guide tube, wherein the inner tube for inserting the main communication cable to be laid in the pipe, and a pre-Symbol fraction outer tube for inserting the communication cable for laying the branch pipes With a heavy structure,
Said outer tube has a communication cabling guide tube into the ground conduit according to claim 8 or 9, characterized in that it has a width capable of accommodating said communication cable multiple. The said branch hole of the said guide pipe is opened in the position shifted from right under the said branch pipe opening so that the fluid from the said branch pipe may not flow in. Guide pipe for laying communication cables in underground conduits. In the underground conduit where a plurality of branch pipes are branched into the main pipe provided between the manholes, the communication cable is laid from the manhole to the branch pipe,
A guide pipe containing a plurality of the communication cables in parallel in the width direction is laid in the main pipe,
In the branch pipe, the communication cable drawn from the guide pipe is laid,
In the guide tube, in the width direction of the guide tube, the plurality of communication cables are located closer to the one of the manholes so that the one corresponding to the branch tube is located on the outer side in the width direction of the guide tube. Underground pipe laying structure for communication cables, characterized by being parallel . The guide pipe is installed on the upper side of the main pipe, and connected to the guide pipe from the vicinity of one manhole to the left and right sides of the branch pipe connected to the left and right in the cross section of the main pipe, respectively. 13. The underground cable laying structure for a communication cable according to claim 12 , wherein the communication cable is connected in parallel so as to correspond to the branched pipe. A communication cable is inserted into the guide pipe from the vicinity of each manhole, symmetrically at a substantially central position of the main pipe or a position where the number of the branch pipes is substantially halved between the manholes. An underground pipe laying structure for a communication cable according to claim 12 or 13 .

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