JP2761983B2 - Laying method of temperature distribution measurement cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for laying a temperature distribution measuring cable for measuring a temperature distribution in concrete when constructing a concrete structure such as a concrete dam, a tunnel or a building. .

[0002]

2. Description of the Related Art Recently, an RCD (Roller Compacted Dam) method has attracted attention as a method of constructing a concrete dam. This method is a method of transporting ultra-hardened concrete to the site with a dump truck, sprinkling it with a bulldozer or wheel loader, and compacting it with rollers etc.
The first lift and the second lift are sequentially driven in a layered manner from below. Since a concrete layer of up to 1m or more can be cast in a single casting, the construction speed is high and the same level of strength can be obtained with a small amount of cement, so besides dams, tunnels, roads, buildings, etc. It is considered useful for application to concrete structures.

[0003] When concrete is poured into such a concrete structure, heat is generated due to a cement hydration reaction, and the temperature affects the strength of the concrete. Therefore, it is not possible to measure the temperature to control it. This is one important factor in construction. In temperature measurement, a distributed temperature measurement system using an optical fiber cable or the like is very effective because the temperature can be measured over the entire length of the measurement cable. Therefore, a temperature distribution measurement cable is laid in the concrete structure. In order to accurately measure the temperature distribution, the temperature distribution measuring cable must be correctly laid at a predetermined position and fixed so that the position does not change.

[0004] When using liquid concrete called ready-mixed concrete, a cable can be connected to a frame such as a reinforcing bar of a structure and fixed.

[0005] However, in the case of a method such as the above-mentioned RCD method in which concrete needs to be cast and rolled from above with a bulldozer or the like, it is difficult to fix the temperature distribution measuring cable. In the RCD method, the first
The lift and the second lift are installed in layers from below, but conventionally, a cable to be laid at the top end of the first lift is arranged, and concrete nails are installed along the cable as necessary. Then, the cable was fixed by means such as fixing to a concrete nail, concrete was poured from above, and then compacted.

[0006] As another method, a long angle member is disposed at the top end of the first lift, a cable is disposed along the angle member, and concrete is poured from above to form a concrete layer. Then, there was a method of compacting the concrete layer.

There has also been a method in which a portion where a cable is laid is re-excavated to form a groove, the cable is arranged along the groove, and then concrete is cast.

[0008]

In the method of arranging a cable to be laid on the top of the first lift, forming a concrete layer thereon, and compacting the concrete layer from above, a bulldozer is used when compacting. If the cable is stretched along the moving direction of the load roller or the cable is stretched or the installation position is shifted, not only will the cable jacket be damaged, but also undesired stress will occur, and in the worst case the cable will be disconnected. There is a risk of doing it.

[0009] Further, there is a possibility that a portion in contact with the large-diameter aggregate bends or curves along the outer periphery of the aggregate and is disconnected. The effect is small when the concrete under the laying is hard, but the effect is particularly large when the concrete under the laying is soft. In particular, when laying an optical fiber cable, if a bent or curved portion occurs, transmission light leaks to the outside at that portion, which may cause not only transmission loss but also undesired noise. Further, even if an angle member is used and a cable is laid along the angle member, a useless bent portion is generated at a portion where the aggregate abuts, and transmission loss similarly occurs. Furthermore,
The angle member has to be buried in a concrete structure together with the cable, so that the operation is troublesome and the laying cost is extremely high. In addition, re-digging concrete to form a groove is a time-consuming and troublesome operation, so that the laying cost becomes extremely high. The same is true when placing concrete nails.

Thus, especially in the RCD method,
Due to the concrete placement of the upper layer, the position of the cable for temperature distribution measurement is shifted, the cable is damaged or broken due to compression by aggregate, etc., and the temperature measurement accuracy is easily degraded due to bending or bending of the cable. there were.
The temperature distribution measurement cable will not be suitable for temperature measurement if the surface is protected firmly by coating etc.,
Basically susceptible to damage. In addition, it takes time and effort to form grooves by re-digging and to arrange nails and angle members,
It ruins the precious advantage of the efficiency of the RCD method.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to eliminate the above-mentioned drawbacks, not to cause displacement, not to cause breakage or disconnection, not to impair accurate temperature measurement, and to increase the execution time and labor. Another object of the present invention is to provide a cable laying method that can appropriately lay various temperature distribution measuring cables, particularly optical fiber cables, in a concrete structure.

[0012]

Means for Solving the Problems The present inventor conceived of using a dummy cable to compact a concrete layer from above the dummy cable, and obtained a good result as a result of trial. Thus, the present invention provides a method for laying a temperature distribution measuring cable in a concrete structure, comprising: (a) placing a concrete layer; (b) arranging a dummy cable on the concrete layer; The concrete layer is pressed from above the dummy cable and the dummy cable is pressed into the concrete layer, (d) the dummy cable is removed to form a laying groove, and (e) a temperature to be laid in the laying groove. A method for laying a temperature distribution measurement cable, which includes arranging a distribution measurement cable, is provided.

[0013]

The concrete layer is formed by depositing concrete, a flexible dummy cable having a diameter larger than the diameter of the cable to be laid is placed on the concrete layer, and the concrete layer is placed on the dummy cable. By rolling, a groove for arranging the cable for temperature distribution measurement is formed at the same time as the rolling of the concrete layer,
It is not necessary to add a process, and by arranging the cable to be laid in the laying groove, the cable position does not shift. Since the cable is present in the groove, the cable is not damaged when the upper layer is cast and compacted.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The cable laying method according to the present invention will be described with reference to FIGS.
Description will be made based on (h).

First, as shown in FIG. 1A, a concrete layer 2 is cast on a ground 1 as a first lift. next,
As shown in (b), the dummy cable 3 is arranged on the concrete layer 2. It is preferable that the dummy cable 3 has an outer diameter larger than the outer diameter of the cable to be laid, and has appropriate flexibility. As the dummy cable, for example, a stainless steel wire can be used. It is desirable from the viewpoint of work efficiency that the dummy cable be continuously unreeled and arranged from the winding spool on the concrete layer 2. The required number of cables can be arranged according to the size of the structure and the like.

Next, as shown in FIG. 1C, the concrete layer 2 is compacted by a bulldozer or a roller 4 from above the dummy cable. By rolling, 9
As shown in (d) of the cross-sectional view from the direction rotated by 0 degrees, the concrete layer 2 is fixed, and the dummy cable 3 is embedded near the surface of the concrete layer. Next, the dummy cable is wound up and removed. This allows
As shown in (e), the laying groove 5 having a diameter slightly larger than the diameter of the temperature distribution measuring cable to be laid after the dummy cable 3 is removed is formed at the top end of the first lift. Since the laying groove 5 is formed in the concrete fixed by rolling, the laying groove 5 serves to protect the temperature distribution measuring cable to be laid.

Thereafter, as shown in (f), a temperature distribution measuring cable 6 to be laid in the laying groove 5 is arranged. As the temperature distribution measuring cable, an optical fiber cable is preferable, but a thermocouple type cable or the like can also be used. After the cable 6 is arranged, the cable 6 may be partially fixed in the laying groove 5 using mortar. Finally, as shown in (g), after placing another concrete layer 7 as a second lift on the top of the first lift, (h)
As shown in FIG.

If necessary, the process is repeated to form the final concrete structure.

[0019]

As described above, according to the present invention,
Since a laying groove is formed at the top of the first lift using a dummy cable having flexibility, various temperature distribution measurement cables are arranged in the laying groove, and another concrete layer is cast thereon. Since the cable to be laid is protected by the wall of the laying groove, the cable can be laid in a concrete structure without being damaged and generating unnecessary stress. Furthermore, since the dummy cable can be easily removed by rolling after rolling and can be reused, the laying operation is also easier than in the case where a wooden frame or the like is used. Since a groove for arranging the cable for temperature distribution measurement is formed at the same time as the compaction of the concrete layer, no additional process is required.By arranging the cable to be laid in this laying groove, There is no deviation. Thus, it has become possible to lay the temperature distribution measurement cable at a predetermined position without deteriorating the measurement accuracy, while taking advantage of the RCD method.

[Brief description of the drawings]

FIG. 1 is a drawing sequentially showing a series of steps of a method for laying a temperature distribution measuring cable according to the present invention, wherein (a) is a cross-sectional view of a state where a concrete layer is cast on the ground,
(B) is a sectional view showing a state where a dummy cable is arranged on a concrete layer, (c) shows a state where the concrete layer is compacted from above the dummy cable, and (d) is a state where the concrete layer is buried in the fixed concrete layer. (C) is a cross-sectional view from a direction rotated by 90 degrees, (e) is a cross-sectional view showing a laying groove after removing the dummy cable, and (f) is a cross-sectional view showing the inside of the laying groove. Is a cross-sectional view in which a temperature distribution measuring cable is disposed, and (g) is a cross-sectional view in a state in which another concrete layer is further disposed above, and (h) shows a state in which the concrete layer disposed thereon is compacted. .

[Explanation of symbols]

 Reference Signs List 1 ground 2 concrete layer (first lift) 3 dummy cable 4 bulldozer 5 laying groove 6 temperature distribution measurement cable 7 another concrete layer (second lift) 8 bulldozer

Claims (1)

(57) [Claims] 1. A method of laying a temperature distribution measuring cable in a concrete structure, comprising: (a) placing a concrete layer; (b) arranging a dummy cable on the concrete layer; The concrete layer is compacted from above and the dummy cable is pushed into the concrete layer, (d) the dummy cable is removed to form a laying groove, and (e) a temperature distribution measuring cable to be laid in the laying groove. A method for laying a temperature distribution measuring cable, comprising: