JPH036399B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for repairing the outer surface of a pipeline laid underground (under a road), such as a gas pipeline, and more specifically, to a method for repairing the outer surface of a pipeline laid underground (under a road). The area (for example, a pipe joint) is excavated locally and exposed in a pit open to the ground, and a cover is wrapped and fixed on the outside to surround it, and the cover is filled with resin and solidified to repair the area. This relates to an external surface repair method in which the repair is carried out in a manner that seals the surface.

[Prior art]

Conventionally, methods for repairing the external surface of underground pipes as described above are known, such as those described in Japanese Patent Publication No. 53-3099, Japanese Utility Model Application Publication No. 52-17921, and the like.

To carry out such a repair, for example, taking seal repair at a pipe joint as an example, the repair is carried out according to the following work steps.

Before starting repair work, detect the position of the pipe joint to be repaired.

A vertical hole is excavated using an excavating tool or the like at the position of the detected pipe joint, and the buried pipe joint is exposed in the excavated vertical hole.

Sandblast the exposed outer circumferential surface of the pipe joint to remove dirt and sand adhering to the surface and clean it to ensure good adhesion of the sealant.

A urethane primer is applied to the cleaned outer circumferential surface and moistened to improve the adhesion of the sealing material that will be filled later.

Next, a sealing cover is wrapped around the pipe joint to enclose it.

A liquid sealing material made of a two-component urethane resin that cures at room temperature is injected into the sealed sealing cover.
Fill the space between the pipe joint and the sealing cover and solidify.

After curing, an airtightness test is conducted, and once airtightness is confirmed, backfilling and compaction are performed to complete the repair process.

[Problem to be solved by the invention]

In the above-mentioned repair work, the problem is that if there is a leak at the pipe joint at the repaired location, the leaking gas may permeate into the soil layer before excavation, and the leakage may also occur after the excavation. It is predicted that gas will flow out from the exposed pipe joint, fill the excavated shaft, and mix with air to form an explosive atmosphere.

Therefore, if sparks are generated during the excavation process due to the impact between the excavation tool and rocks within the formation, or sparks caused by the collision between the blast sand and the laying pipe during the sandblasting process, sparks will be formed by leaked gas. There is a risk of igniting the explosive atmosphere gas and causing an explosion.

The present invention aims to solve the problems that occur in the conventional construction methods as described above.

[Means to solve the problem]

In order to achieve this objective, the present invention exposes the repaired part of an existing pipe laid underground in a hole opened above ground by excavation, and performs a cleaning treatment by spraying sandblasting on the exposed pipe body. After that, a repair cover is wrapped and fixed on the outside of the pipe body, and the seal is repaired by filling and solidifying resin injected into the cover. The area to be repaired is excavated, and (B) the vacuum suction is continued during the cleaning process by sandblasting on the exposed pipe body after excavation, and the injected sand is collected while ventilating the gas remaining in the excavation hole. It is characterized by the following.

[Effect]

According to this type of repair method, during the excavation process and the cleaning process using sandblasting, the gas inside the excavation hole is constantly sucked out by the vacuum suction action, and the work progresses while providing ventilation. Even if there is a gas leak at the repaired area, the formation of an explosive atmosphere inside the excavation hole is prevented, and even if sparks are generated during excavation work or sandblasting, there is no risk of an explosion. This can be prevented, and repair work can be carried out safely because the work can be done from outside the excavated hole.

〔Example〕

An embodiment of the repair method according to the present invention will be described below with reference to the drawings.

In the figure, reference numeral 1 indicates an existing underground pipe to be repaired, which is installed for a long time under a road or the like via a water pipe joint A, as seen in gas pipes. 2 is a sheet-like repair cover that is wrapped around the outer periphery of the pipe body in order to repair the pipe joint part A exposed by excavation from the outside.This repair cover 2 is airtight with resin coating on the inner surface It is made of a flexible woven fabric and is fastened with a fastener or the like to airtightly cover the outer periphery of the pipe joint A to be repaired. 3 is an injection pipe for resin (sealing material) to be injected into the repair cover 2, and 4 is a pipe for discharging the air stagnant in the space between the cover 2 and the pipe joint A in accordance with the resin injection. This is an air vent tube for

Reference numeral 5 denotes a vertical hole excavated for repair, and 10 is a vacuum excavator for excavating the hole.A vacuum pump 12 is driven by an engine 11, and the earth and sand sucked in by this vacuum pump 12 is separated and evacuated. It is equipped with a hopper section 13, a filter section 14, a compressor 15, a sandblasting device 16, and the like. Further, the reference numeral 6 is a suction hose connected to the vacuum pump 12, the reference numeral 7 is an air hose, the reference numeral 8 is an excavation tool, and the reference numeral 9 is a sandblasting injection nozzle member.

Next, the work steps of the repair method according to the present invention will be explained.

Before carrying out repair work, the position of the pipe joint A to be repaired is detected by a known method.

In order to expose the detected position of the pipe joint part A on the ground, a pit 5 of the minimum necessary size is excavated using an air-operated excavation tool 8.

In this case, gas may be leaking from the pipe joint A to be repaired, and the leaked gas may penetrate into the soil layer around the pipe joint A, and sparks generated during excavation work may ignite the leaked gas. Furthermore, there is a risk of local explosion. For this purpose, the excavated earth and sand are discharged with a suction hose 6 connected to the vacuum pump 12, and the gas that permeates into the soil layer is also vacuum-suctioned to remove the excavated earth and sand from the shaft being excavated.
Ventilate the inside by replacing the air with air from outside to prevent the formation of an explosive atmosphere at all times.

In this way, the pipe joint part A to be repaired is exposed inside the excavated shaft 5, but suction ventilation is carried out even after the shaft 5 is excavated so that the suction ventilation is performed by the suction hose 6 against the gas leaking from the pipe joint part A. Continue to do so.

Next, remove the earth and sand adhering to the exposed circumferential surface of the pipe joint part A by operating the injection nozzle member 9 connected to the sandblasting device 16,
Clean the surface. This removed earth and sand and the injected sand are both discharged by the suction hose 6, and the suction simultaneously ventilates the inside of the pit 5, so even if sparks are generated by the sandblasting, an explosion will occur. You can work safely without any problems.

Next, a urethane-based primer is applied to the cleaned outer peripheral surface and moistened.

After that, a fastener extending long from the repair cover 2 is dropped into the vertical hole 5, and pulled up through the lower surface of the pipe joint part A using a hook rod or the like.
The repair cover 2 is wrapped around the outer periphery of the pipe joint part A by tightening the fasteners. At this time, the air vent pipe 4 is positioned directly above and encapsulated.

When the above-mentioned work is completed, the driving of the vacuum pump 11 is stopped.

, This process is performed in the same procedure as the conventional process, and the series of operations in the repair process is completed.

By performing the above-mentioned work, the repair worker does not have to enter the excavation shaft 5 to perform a series of operations, and can always perform the work outside the excavation shaft 5, thereby further ensuring safety. . Note that since there is no need to enter the excavated shaft 5, the area of the excavated shaft 5 can also be minimized.

〔Effect of the invention〕

As explained above, according to the repair method according to the present invention, when repairing gas pipes laid underground, vacuum suction is always applied during the excavation process and the cleaning process using sandblasting. Since the gas inside the excavation hole is sucked out and the work is carried out while providing ventilation, even if there is a gas leak at the repair site, the formation of an explosive atmosphere inside the excavation hole is prevented, thus preventing the formation of an explosive atmosphere during the excavation work. Furthermore, even if sparks are generated during sandblasting, the risk of an explosion or the like is prevented, and since the work can be done from outside the excavation hole, repair work can be carried out extremely safely.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view to explain the repair method in which a repair cover is wrapped around the joint of an underground pipe, and a sealing material is filled and solidified. Figure 2 is an explanation of the vacuum suction excavation process and cleaning process. FIG. 1...Existing piping, 2...Repair cover, 3...
Resin injection pipe, 4... Air vent pipe, 5... Excavation pit, 6... Vacuum suction hose, 7... Air hose,
8...Drilling tool, 9...Sandblasting injection nozzle member, 10...Vacuum excavation vehicle, 11...Engine, 12...Vacuum pump, 13...Hopper part, 1
4...Filter section, 15...Compressor, 16
...Sandblasting equipment, A...Pipe joint part.

Claims (1)

[Scope of Claims] 1. The repaired part of an existing pipe laid underground is exposed in a hole opened above ground by excavation, the exposed pipe body is cleaned by sandblasting, and then the outside of the pipe body is cleaned. In this construction method, seal repair is performed by enclosing and fixing a repair cover, filling and solidifying resin injected into the cover, and excavating the area to be repaired by removing earth and sand from the excavation process while sucking it out using a vacuum. The outer surface of an underground pipe characterized in that the vacuum suction action is continued during the subsequent cleaning process by sandblasting on the exposed pipe body, so that the ejected sand is recovered while ventilating the gas accumulated in the excavation hole. Repair method.