JPH0672435B2 - Manhole expansion method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a manhole for connecting a cable drawn into a pipeline, for example, an existing lead-covered OF cable is a CV.
The present invention relates to a method for expanding a cable by a predetermined length when exchanging the cable.

[Conventional technology]

Conventionally, lead-covered OF cables (oil-immersed insulating paper cables) have been widely used as underground power transmission lines.
It has many advantages over cables and is replaced by CV cables (crosslinked polyethylene insulated cables). Since this CV cable does not require a refueling device, it does not cause an oil leakage failure and has a low construction cost. In addition, the construction and maintenance inspection are easy together with the fact that no metal coating is required, which is economically advantageous. Further, it has a feature that the transmission capacity is large due to the high operating temperature.

However, since the CV cable is lightweight and has low rigidity, it has a drawback that the amount of extension of the cable is large and the manhole for storing the cable is also large.
For example, the length of the existing manhole that houses the OF cable is about 6 m, while the CV cable requires a manhole of about 7.5 m. Therefore, when replacing the existing OF cable with the CV cable, it is necessary to expand the manhole by the required length. Conventionally, as shown in FIG. 11, the manhole 1 has a ground surface along the side wall surface of the existing manhole 1. An open cutting method is mainly used to open a hole indicated by a one-dot chain line to construct a manhole extension indicated by a broken line.

[Problems to be Solved by the Invention]

However, the manhole expanding method by excavation described above has various problems as follows. In other words, it cannot be constructed on a road controlled by excavation by new pavement, it requires a large amount of money, and the construction days are long and the road is occupied during construction. Takes.

As another method of exchanging OF cable for CV cable,
As shown in FIG. 12, by using a synthetic resin ring 3 attached to the cable 2 without expanding the manhole 1, it is necessary to use a means which is praised as offset reinforcement for forcibly suppressing the extension amount of the cable 1. However, the B-type manhole cannot be used because the axial force on the straight side and the sleeve side are unbalanced, and the usable manhole is limited. Moreover, since it is necessary to reinforce each cable, the cost increases in proportion to the number of lines.

The present invention has been made in view of such conventional problems, and it is an object of the present invention to provide a manhole expansion method that can eliminate various conventional problems at once by expanding a manhole without deletion. It is a specific subject.

[Means for Solving the Problems]

The present invention has the following manhole expansion method as a technical means for achieving the above-mentioned problems. That is, the manhole expansion method according to the present invention is a method of expanding one side wall surface of a manhole along a pipeline by a predetermined length. Inside the manhole, the equipment carried in from the neck of the manhole propels the manhole in the expansion direction. The apparatus is installed, a tubular steel box is assembled, the steel box is installed on the propulsion device with the opening of the steel box facing the expansion direction, and the artificial wall in the expansion direction is attached to the propulsion device. Of the steel box and the steel box is removed in the pre-process or post-process of assembling, and the steel box is excavated while propelling the steel box in the expanding direction by the propulsion device, and after excavating a predetermined length, the excavated hole , The bar is arranged, and the formwork is attached,
The gist of the method is to pour concrete into the formwork and then to remove the formwork.

[Operation] When excavation is performed while propelling the steel box to a predetermined length, a hole corresponding to the area to be expanded is formed.
Then, by solidifying the periphery of this hole with concrete, an expanded part of the manhole is completed. In this way, by expanding the manhole without cutting, it is possible to eliminate the drawbacks of the conventional expanding method using cutting.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

1 to 10 show a manhole expanding method according to an embodiment of the present invention in the order of steps. First, as shown in FIG. 1, a protection member 10 is wrapped around a cable (not shown) and tightened with a string 12 to protect the cable from damage during construction. Then, prior to the construction, the chemical solution injection hole is drilled in order to strengthen the ground by chemical solution injection. This drilled hole is the neck 1A of the manhole 1,
Since 1B has a diameter of about 1 m and the boring machine cannot be carried into the manhole 1, it is carried out manually using a water jet. The rod 14 is inserted into the injection hole thus drilled, and the chemical solution is injected through this rod. The chemical liquid used for this purpose should be selected as appropriate depending on the soil quality and groundwater at the expansion site.

Then, as shown in FIGS. 2 and 3, the material is loaded from the manhole necks 1A and 1B and the propulsion device 16 is installed in the expansion direction. First, as shown in FIG.
As shown in Fig. 3, the reaction girder portion 16B is placed on the girder portion 16A so that the reaction force girder portion 16B is applied to the side wall surface in the opposite direction to the expansion direction (right side in the figure). A hydraulic jack 16C, which serves as a propulsion source, is installed on the side surface of the reaction force girder portion 16B in the expansion direction, as illustrated on the portion 16A. Further, the rectangular box-shaped steel box 18 is assembled, the steel box 18 is applied to the side wall surface to be expanded, and the hydraulic jack 16C is set to the steel box 18 so that it can be propelled.

As shown in FIG. 4, the steel box 18 has a frame formed by screwing an angle member 18A, and a steel plate 18B is attached to the frame.
It is assembled by fixing with screws. Since it is divided into a large number of members before assembly, it can be easily carried in from the manhole necks 1A and 1B. Further, as shown in FIG. 5, the steel box 20 has a shape having an opening area which is considerably larger than the cross-sectional area of the existing pipeline 20, and the existing pipeline 20 faces the opening so as to face each other. 16 toward the extension direction
Placed on A. Two hydraulic jacks 16C are provided as shown in the figure, and are set at the center of gravity of the steel box 18 so that the propulsive force is evenly applied to the entire circumference of the opening of the steel box 18.

As a pre-process or post-process of installing the propulsion device 16 and assembling the steel box 18, as shown in FIG. 6, the artificial wall, which is a side wall in the expansion direction, is demolished, and the demolished part is made of steel. Box 18 is pressed. This demolishing work of the artificial wall uses tools that can be easily carried in from the manhole necks 1A, 1B such as breakers and concrete cores, but since there is a lot of dust during the work, sufficient dust is taken by a dust collector or blower. Be done.

Next, as shown in FIG. 7, the hydraulic jack 16C is operated to propel the steel box 18 in the expansion direction indicated by the arrow, and then excavation is performed. Hori Susumu. Once the steel box 18 has been propelled to the predetermined position indicated by the alternate long and short dash line, it is pre-opened and the filler is injected into and filled from the graft hole into the void on the outer circumference of the steel box 18, thereby causing the depression of the road surface due to the void. After preventing the above and fixing the steel box, as shown in FIG. 8, the temporary materials such as the propulsion device 16 are removed to the outside of the manhole 1. Furthermore, the eighth
As shown in the figure, the reinforcement bars 22 and the formwork 24 are attached so as not to collapse during the concrete pouring in the next step. After that, the hose 26 is supplied from the ground pump car into the on-hand mold 24 to supply the fresh concrete, and the concrete is placed. Once this ready-mixed concrete has set sufficiently, the formwork 24 is removed, as shown in FIG.
The manhole extension 28 made of concrete is completed,
As shown in the figure, the new CV cable has a manhole extension.
The line is entered through 28, and all work is completed.

〔The invention's effect〕

According to the present invention, since the manhole is expanded without cutting through the above steps, the following effects can be obtained.

About the construction cost of the conventional manhole expansion method by excavation
It can be reduced to 60% and about 90% when offset reinforcement.

Approximately one-half the construction days of manhole expansion method by excavation
Can be shortened to

Not subject to legal restrictions such as drilling restrictions.

It can also be applied to B type manholes.

Because it does not excavate, it occupies less road surface during construction.

Maintenance is easy because no offset reinforcement is required.

The connection space for expansion can be secured.

[Brief description of drawings]

1 to 10 show, in order, steps of a manhole expansion method according to one embodiment of the present invention. FIG. 1 is a sectional view of a cable protection and chemical solution injection step, and FIG. Sectional view of installation process, Fig. 3 is a sectional view of assembly process of steel box, Fig. 4 is an exploded perspective view of steel box, Fig. 5 is a cutaway perspective view of propulsion and excavation process, and Fig. 6 is demolished artificial wall. Process cross-section, Fig. 7 cross-section of propulsion process, Fig. 8 cross-section of rebar / formwork process, Fig. 9 cross-section in completed state after form-removal, and Fig. 10 cable entry. FIG. 11 is a cross-sectional view of the state, FIG. 11 is an explanatory view of a conventional manhole expanding method by excavation, and FIG. 12 is a cross-sectional view of a state in which offset reinforcement is applied. 1 ... Manhole, 1A, 1B ... Manhole neck, 16 ... Propulsion device, 18 ... Steel box, 22 ... Reinforcing bar, 24 ... Formwork.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Enohara Inventor Hiroyuki Enohara Shiokoji-Kyoto, Kyoto Prefecture Higashishioji-cho, Karasuma West, 579 Kansai Electric Power Co., Inc. Kyoto Branch (72) Inventor Koichiro Nakayama Shiokoji, Shimogyo-ku, Kyoto-shi, Kyoto Prefecture Karasumaru Nishi entering Toshio Kojimachi 579 Kansai Electric Power Co., Ltd.Kyoto Branch (72) Inventor Teruyuki Ichihara 10 Higashikujo Nakatonoda-cho, Minami-ku, Kyoto City, Kyoto Prefecture Kansai Electric Power Co., Ltd.Kyoto Electric Power Plant (72) Inventor Tadayuki Tokuda Kyoto 10 Kanto Electric Power Co., Ltd.Kyoto Electric Power Co., Inc., Minami-ku, Minami-ku, Kyoto-shi, Kyoto Prefecture (72) Inventor Miyasaku Yosaku, Kyoto-ku, Higashi-kujo Higashiiwamoto-cho, Minami-ku, Kyoto-shi, Kyoto Igarashi Industry Co., Ltd. Inventor Katsuhiko Sakai 6 Higashikujo Higashiiwamotocho, Minami-ku, Kyoto City, Kyoto Prefecture Igarashi Industry Co., Ltd. Kyoto Branch (72) Inventor Daisuke Igarashi Kyoto Prefecture Kyoto Shinan District Tokujo Higashiiwamoto-cho, 6 fifty storm Industrial Co., Ltd. of Kyoto in the branch office

Claims (1)

[Claims] 1. A method for expanding a side wall of a manhole along a duct by a predetermined length. Inside the manhole, a propulsion device is installed in a direction of expansion by equipment carried in from the neck of the manhole, and a cylinder is installed. -Shaped steel box is assembled, the steel box is installed on the propulsion device with the opening of the steel box facing the expansion direction, and the artificial wall in the expansion direction is installed on the propulsion device and the steel box is assembled. Demolished in the pre-process or the post-process, excavating the steel box while propelling the steel box in the expansion direction by the propulsion device, and after excavating a predetermined length, the excavated hole is barred, and A manhole expansion method characterized by the steps of attaching a formwork, pouring concrete into this formwork, and then removing the formwork.