JP4968129B2 - Intercavity filling method for buried double pipes, anticorrosion management method for buried double pipes - Google Patents

Description

  The present invention relates to a method for filling an inter-cavity of an embedded double pipe and a method for managing the anticorrosion state of the embedded double pipe.

  Conventionally, regarding the method of filling underground cavities, “The conventional cavities filling method is mainly due to slurry material containing cement, soil contamination. There is concern about water pollution. There is also a problem of disposal of industrial waste. As a technology with the theme of "there was a method of filling the underground cavities with dry powder granules mainly composed of fine crushed stone powder and coal ash using air flow." Specifically, the dry granular material is introduced into the cavity by a particulate transportation vehicle through a transportation pipe disposed at one end of the cavity using an air flow, while the vacuum transportation vehicle is disposed through an exhaust pipe disposed at the other end of the cavity. Means for sucking the air in the cavity, or means for letting the dry granular material flow in by means of air flow by the granular material transportation vehicle through the transport pipe having the downward slit-like opening piped to the inner end of the cavity It was adopted. "Has been proposed.

  Further, “a method is disclosed in which a powder that does not have buoyancy and can be premixed even if there is a difference in specific gravity is hydrated after being filled with a filler by a powder filling method that can be filled into a cavity. As a technique for the purpose, “As a basic method, after filling a dry powder into a cavity, a liquid is applied to the powder and humidified. In a specific first method, a liquid supply pipe having an orifice for dripping liquid in advance is provided in the cavity to supply liquid. In the second construction method, liquid is stored in advance in the lower part of the cavity, and then liquid is supplied by filling with dry powder. In the third construction method, after filling dry powder into a cavity existing underground, moisture is supplied by inflow of groundwater or rainwater to wet the powder. As the powder, a powder obtained by mixing cement powder and fine crushed stone powder or a powder obtained by mixing cement powder with fly ash is selectively employed. Is proposed (Patent Document 2).

JP 2002-155527 A (summary) JP 2006-97298 A (Summary)

After filling the inter-cavity of the buried double pipe using the technique described in Patent Document 1, an anticorrosion current may be supplied in order to provide an anticorrosion to the buried double pipe. In this case, a predetermined amount of moisture is supplied to the dried granular material so that the anticorrosion current reaches the inner tube of the buried double tube.
As a method for supplying moisture to the dry granular material, for example, the technique described in Patent Document 2 can be used.

On the other hand, after laying the buried double pipe by the above-mentioned method, in order to check that the anticorrosion current has reached the inner pipe and to manage the anticorrosion state, the probe electrode that is electrically connected to the inner pipe is connected to the inner pipe. It may be placed on the surface to measure voltage and current.
At this time, depending on the component of the dry granular material, the component may be dissolved as ions in the moisture, and may be electrically reacted with the anticorrosion current and deposited on the surface of the probe electrode. This electrode deposit is not preferable from the viewpoint of anticorrosion management because it prevents accurate measurement of current and voltage using the probe electrode.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for filling an inter-cavity of an embedded double pipe that does not generate deposits on a probe electrode.

An inter-tube cavity filling method for an embedded double pipe according to the present invention is a method of filling an inter-tube cavity of an embedded double pipe using a dry powder, and the gap between the pipes from one end of the embedded double pipe Filling the inter-cavity cavity with the dry powder granule by allowing the dry granule to flow into the cavity using an air flow, and a predetermined amount to the dry granule filled in the inter-tube cavity A step of supplying the moisture of the inner tube and a step of disposing a probe electrode on the inner tube surface in order to manage the anticorrosion state of the anticorrosion performed on the inner tube of the embedded double tube , The dry granular material has a Si component of 61.1% or more by weight.

  According to the inter-tube cavity filling method of the buried double pipe according to the present invention, the inter-pipe cavity of the buried double pipe is filled using a dry granular material composed of components that are difficult to produce precipitates. Even if the probe electrode is disposed on the inner tube and the corrosion prevention management is continuously performed, no deposits are generated on the probe electrode, and accurate corrosion prevention management can be performed.

Embodiment 1 FIG.
FIG. 1 is a side sectional view showing a state in which the inter-cavity filling method for an embedded double pipe according to Embodiment 1 of the present invention is being carried out.
When various pipes are laid, if there are railways, waterways, underground structures, or other structures in the vicinity, a propulsion method that pushes steel pipes or the like with a hydraulic jack is used. This steel pipe has a double structure which will be described later with reference to FIG.
Also, in places where there is a possibility of being affected by earth pressure or ground fault current near the transmission tower, piping with a double pipe structure may be used for the purpose of protecting the inner pipe.

The double pipe 10 is a pipe such as a steel pipe buried in the above-described underground.
The jet pack vehicle 20 mixes the dry granular material 40 with the compressed air in the tank and transfers it to the place where the double pipe 10 is buried, and the dry granular material 40 is compressed by compressed air pressure from one end of the double pipe 10. Is pumped into the double pipe 10.
The vacuum wheel 30 assists the filling of the dry granular material 40 into the double tube 10 by sucking the air in the double tube 10 with negative pressure from the opposite end of the double tube 10. .

FIG. 2 is a cross-sectional view of the double tube 10.
The double tube 10 has a double structure of an outer tube 10a and an inner tube 10b. The inner pipe 10b is a pipe for carrying a transported object such as a fluid, and is also called a main pipe. The outer tube 10a is a pipe provided outside the inner tube 10b from the above-described viewpoint.
The space between the outer tube 10a and the inner tube 10b is a cavity, and in order to carry out the electrocorrosion protection described below, after filling the dry granular material 40 by the method described in FIG. A predetermined amount of water is supplied and wetted using the technique described.

FIG. 3 is a diagram illustrating a state in which the double pipe 10 is subjected to electrocorrosion protection.
In FIG. 3, an external electrode 50 is embedded outside the double tube 10, the positive electrode of the DC power supply device 60 is connected to the external electrode 50, and the negative electrode is connected to the inner tube 10 b of the double tube 10. An anticorrosion current is passed through the inner tube 10 b of the heavy tube 10.
At this time, if the dry granular material 40 filling the space between the outer tube 10a and the inner tube 10b remains dry, the electric conductivity is hardly exhibited, and the anticorrosion current does not flow into the inner tube 10b. Therefore, a predetermined amount of moisture is supplied to the dry powder body 40 so that the anticorrosion current also flows into the inner tube 10b.

Further, in order to manage whether or not the anticorrosion current is supplied to the inner tube 10b, a probe electrode 70 that is electrically connected to the inner tube 10b is disposed on the surface of the inner tube 10b, for example.
The anticorrosion manager of the double tube 10 measures, for example, the current flowing through the inner tube 10b and the tube-to-ground potential of the inner tube 10b with the measuring device 80 installed on the ground, and sufficient anticorrosion current is supplied to the inner tube 10b. Manage whether or not.

  The method for filling the inter-tube cavity of the double tube 10 and the method for managing the anticorrosion state of the double tube 10 have been described above with reference to FIGS.

When the probe electrode 70 is disposed and the anticorrosion state is continuously managed as shown in FIG. 3, precipitates may be generated on the surface of the probe electrode 70 over time.
Such precipitates are likely to occur when, for example, the dry powder 40 contains a large amount of calcium (Ca). This is because Ca dissolves as ions in the moisture of the dry powder 40 and crystallizes on the surface of the probe electrode 70.

If precipitates are generated on the surface of the probe electrode 70, it becomes difficult to accurately measure the current flowing through the inner tube 10b and the tube-to-ground potential of the inner tube 10b, which is not preferable from the viewpoint of managing the anticorrosion state.
Therefore, it is considered that the space between the outer tube 10a and the inner tube 10b is filled with the dry granular material 40 in which such precipitates are not easily generated.

In general, for example, silicon compounds such as silicon dioxide (SiO 2) are less likely to dissolve in moisture than Ca.
Therefore, by filling the space between the outer tube 10a and the inner tube 10b using the dry granular material 40 containing a large amount of Si component, it is possible to suppress the generation of the precipitate as described above.

The dry granular material 40 can be efficiently manufactured in large quantities based on powder generated when natural rock is excavated and cut. However, natural rocks may contain a large amount of Ca component, which is not necessarily preferable from the viewpoint of preventing precipitates as described above.
Therefore, for example, by producing a dry granule 40 using a granule obtained by pulverizing a material containing a large amount of Si components such as glass, the dry granule 40 containing a large amount of Si components and hardly causing precipitates is produced. Obtainable. It would be preferable to produce at least a material that contains more Si components than natural rocks by weight.

However, since the Si component and the Ca component contained in natural rock are considered to vary greatly depending on the mining site, the degree of the Si component and the Ca component to be produced is determined according to the individual environment. As appropriate, depending on
For example, a method of pulverizing natural rock to produce a granular material, and mixing this with a granular material produced by pulverizing glass containing Si as a main component is also conceivable.
According to this, since the dry granular material 40 having a higher proportion of Si component than that of the natural rock is obtained, precipitates are generated rather than using the dry granular material 40 manufactured based on the natural rock as it is. It is assumed that it will be difficult.

As described above, according to the first embodiment, the dry granular material 40 is manufactured based on a material containing more Si components than natural rocks in a weight ratio, such as a glass material, and this is used as an outer tube. Since the space between 10a and the inner tube 10b is filled, precipitates are less likely to be generated on the surface of the probe electrode 70 than when the dry granular material 40 is produced based on natural rock.
Thereby, it becomes easy to accurately measure the current flowing through the inner tube 10b and the tube-to-ground potential of the inner tube 10b, and the anticorrosion state of the double tube 10 can be appropriately managed.

Embodiment 2. FIG.
In the first embodiment, a dry granular material 40 is manufactured based on a material containing a large amount of Si component, and the space between the outer tube 10a and the inner tube 10b is used to deposit on the surface of the probe electrode 70. We explained the technique to make things difficult to occur.
In the second embodiment of the present invention, the result of verifying how much the generation of precipitates can be more reliably prevented by using a material containing a specific amount of Si component or Ca component will be described.

FIG. 4 is a diagram showing a verification facility for verifying the optimum components of the dry granular material 40.
In FIG. 4, the dry powder particles 40 are filled in the soil tank 100, the platinum electrode 110 and the pseudo probe 120 are embedded, and a direct current is supplied from a DC power supply 130 provided outside the soil tank 100.
The platinum electrode 110 simulates the external electrode 50 of FIG.
The pseudo probe 120 simulates the probe electrode 70 of FIG. 3 and is formed of the same material (for example, steel) as the double tube 10.
If precipitates are generated on the surface of the pseudo probe 120 in the environment of FIG. 4, it is assumed that the precipitates are similarly generated even if the double tube 10 is filled using the dry powder particles 40. The

  The verification conditions in the second embodiment are as follows.

(1) The size of the soil tank 100 is 289 mm long, 439 mm wide, and 258 mm high.
(2) The dry granular material 40 was uniformly moistened with 30% by weight tap water.
(3) A direct current of 0.01 mA / cm ² is continuously supplied from the direct current power source 130.
(4) The verification time is 90 days (2160 hours).
(5) The composition of the dry granular material 40 is as shown in FIG.
(6) It is visually confirmed whether or not precipitates are generated on the surface of the pseudo probe 120. If even a slight amount of precipitate is generated, it is determined that there is a precipitate.

FIG. 5 is a table showing the results of verifying whether precipitates are generated by variously changing the composition of the dry granular material 40 under the verification equipment of FIG. Here, focusing on the content ratio (weight ratio) of Si and Ca, FIG. 5 is shown so that these can be compared.
In FIG. These verification results show the composition of the dry granular material 40 when no precipitate is generated in the pseudo probe 120.
According to the verification results shown in FIG. 5, it can be seen that the following results were obtained.

(1) Only a verification result having a Si content of 60.7% (test No. = 8) or more can be said to have no precipitate.
(2) Among the verification results in which no precipitate is generated, the one having the maximum Ca content is 18.7% (test No. = 20).

However, test no. In No. 8, it is possible that the content of Ca was very low, and the composition was such that precipitates containing Ca as a main component could not be produced in the first place. Therefore, test no. Next, pay attention to the verification result with the least Ca content.
Here, test no. Focusing on 20, the following verification results are derived.

(3) If the Si content is 61.1% or more, no precipitate is generated.

  Summarizing the above verification results, the following can be derived.

(Verification result 1)
In order to prevent the formation of precipitates, it is necessary that at least 61.1% by weight of the dry granular material 40 is composed of Si components.
(Verification result 2)
In order not to generate precipitates, it is necessary to configure the dry powder body 40 so that at least the weight ratio of the Ca component is 18.7% or less.

  As described above, in the second embodiment, the result of verifying whether or not a material containing a specific amount of Si component or Ca component can be used to more reliably prevent the formation of precipitates has been described.

It is a sectional side view which shows a mode that the inter-tube cavity filling method of the buried double pipe which concerns on Embodiment 1 is implemented. 1 is a cross-sectional view of a double tube 10. It is a figure which shows a mode that the anticorrosion is given to the double tube. It is a figure which shows the verification equipment for verifying the optimal component of the dry granular material 40. FIG. It is a table | surface which shows the result of having verified whether the composition of the dry granular material 40 was changed variously and the deposit produced under the verification installation of FIG.

Explanation of symbols

  10 Double tube, 10a Outer tube, 10b Inner tube, 20 Jet pack car, 30 Vacuum car, 40 Dry powder, 50 External electrode, 60 DC power supply, 70 Probe electrode, 80 Measuring device, 100 Earth tank, 110 Platinum electrode, 120 pseudo probe, 130 DC power supply.

Claims (3)

A method of filling the inter-cavity of an embedded double pipe using dry powder,
Filling the dry intergranular cavity with the dry granular material by flowing the dry granular material into the intertube cavity from one end of the embedded double pipe; and
Supplying a predetermined amount of moisture to the dry powder filled in the inter-tube cavity and moistening; and
In order to manage the anticorrosion state of cathodic protection performed on the inner pipe of the buried double pipe, a step of disposing a probe electrode on the inner pipe surface;
Have
The dry granular material has a Si component with a weight ratio of 61.1% or more. A method of filling the inter-cavity of an embedded double pipe using dry powder,
Filling the dry intergranular cavity with the dry granular material by flowing the dry granular material into the intertube cavity from one end of the embedded double pipe; and
Supplying a predetermined amount of moisture to the dry powder filled in the inter-tube cavity and moistening; and
In order to manage the anticorrosion state of cathodic protection performed on the inner pipe of the buried double pipe, a step of disposing a probe electrode on the inner pipe surface;
Have
The dry powder is
Si component with a weight ratio of 61.1% or more,
A Ca component of 18.7% or less by weight,
An inter-tube cavity filling method for embedded double pipes, characterized in that: A method for managing the anticorrosion state of the inner pipe of an embedded double pipe,
Filling the inter-tube cavities using the inter-tube cavity filling method for embedded double pipes according to claim 1 or 2 ,
Arranging a probe electrode in electrical communication with the inner tube on the inner tube surface;
Supplying an anticorrosive current to the inner tube;
Managing the anticorrosion state of the inner tube by measuring the current or voltage flowing through the probe electrode;
An anticorrosion management method for buried double pipes.

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