JPH0344627B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is a method of continuously covering the outer periphery of a pipe such as a sewer pipe with a cylindrical impermeable membrane when laying a pipe such as a sewer pipe in the ground. The present invention relates to a method of covering a buried pipe body with an impermeable membrane in which the pipe body is laid.

(Prior art and its problems) Conventionally, a propulsion method has been adopted as a construction method for laying pipe bodies such as humid pipes underground.

In this construction method, the pipe body is connected to the shield machine, and the rear end of the pipe body is pressed by a propulsion jack installed in the shaft. A conduit is formed by press-fitting, adding a tube body every time a certain length is pushed, and sequentially press-fitting.

However, the conduit formed in this way
Since it is made by joining pipes of a certain size in sequence, in the case of ground with a lot of groundwater, groundwater may enter the pipe from the joints when the pipe is in service, and the actual sewage flowing inside the pipe may be There is a problem in that the amount of wastewater to be treated at the sewage treatment plant increases significantly because the amount of water flowing is greater than the flow rate.

For this reason, a cylindrical impermeable membrane is placed inside the shield machine in a state in which it is contracted in the length direction, and as the shield machine advances, the impermeable membrane is paid out from the rear end of the shield machine to cover the pipe body. Things started to happen.

However, in this case, when the tube moves forward due to pressure from the shaft side, the outer peripheral surface of the tube comes into sliding contact with the inner peripheral surface of the impermeable membrane fed out from the shield machine side, causing damage to the thin impermeable membrane. There was a problem.

(Object of the Invention) The present invention was made in view of the above problems, and it eliminates the sliding of the pipe body against the impermeable membrane, reduces the propulsion resistance of the pipe body, and makes it easier for other panels to be installed after the pipe body is laid. The present invention provides a method for coating a buried pipe body with an impermeable membrane that can reliably prevent subsidence.

(Structure of the Invention) In order to achieve the above object, the method for coating a buried pipe body with an impermeable membrane according to the present invention is such that, while excavating the ground with a shield machine, the pipe body following the shield machine is installed in a shaft. In the propulsion method, in which the pipe body is laid on the ground by pressing with a device, the end of the cylindrical impermeable membrane stored in the shield machine is fixed to the shaft wall, and then the pipe body is joined to the rear end of the shield machine and pushed. The pipe body is coated with an impermeable membrane by coating the pipe body with an impermeable membrane, while a self-hardening material is injected between the impermeable membrane and the excavated ground, and a lubricant is injected between the impermeable membrane and the outer circumferential surface of the pipe body while the shielding machine The pipe bodies are sequentially joined and propelled as the tunnel excavates, and then, after the series of pipe bodies reach the reaching shaft, a hardening material is injected between the pipe bodies and the impermeable membrane to replace the slipping material. It is something to do.

(Function) The self-hardening material injected between the outer periphery of the shield machine and the excavated ground fills between the impermeable membrane covering the pipe and the excavated ground due to the propulsion of the pipe, and the ground becomes sandy and gravelly. Even if a part of the ground collapses, the sand, etc. in the self-hardening material acts as a plugging material to prevent gaps between sand and gravel, smooth the surface of the excavated ground, and prevent it from collapsing even if a part of the ground collapses. The impermeable membrane is filled with water to prevent it from being damaged by the excavated ground, and the lubricant injected between the impermeable membrane and the pipe body prevents the impermeable membrane from sliding into contact with the pipe body. At the same time, the impermeable membrane is pressed against the excavated ground side to prevent the ground from collapsing and to reduce the propulsion resistance of the shield machine.

(Description of Embodiments) Embodiments of the present invention will be explained with reference to the drawings.
2 is the ground, 2 is a starting shaft excavated and formed at a suitable location in the ground 1, and 3 is the wall of the shaft, in which a starting shaft opening 4 is opened.

Reference numeral 5 denotes a shield machine, and a housing section 7 in which a long cylindrical impermeable membrane 6 made of a vinyl sheet or the like is contracted in the length direction and stored at the rear of the skin plate 5a.
The rear end of the storage portion 7 is opened rearward and is formed at the outlet of the impermeable membrane 6. 8 is the excavation part of the shield machine 5.

9 is the skin plate 5 from inside the shield machine 5
The injection pipe is connected to an injection port penetrating the outer peripheral surface of a, and is equipped with a valve 10, and a self-hardening material 11 made of bentonite, clay, or sand mixed with cement is pumped from a pump 23 (described later) via a pipe 24. The injection pipe 9 is used to inject between the outer periphery of the shield machine 5 and the ground.

Reference numeral 12 denotes a pipe body that follows the shield machine 5, and a large number of pipe bodies are connected one after another, and the rearmost pipe body 1 is
2 is pushed forward.

Reference numeral 14 denotes a ring member fixed to the shaft wall 3 in alignment with the mine entrance 4, and the rear end of the impermeable membrane 6 and the annular packing 15 are fixed watertightly. An injection pipe 17 for injecting a lubricant or a curable material into the space 16 between the water-impermeable membrane 6 and the water-impermeable membrane 6 is attached. Reference numeral 18 indicates a valve provided at an appropriate position on the pipe 17.

Reference numeral 19 indicates a space 16 between the tube 12 and the impermeable membrane 6 at the rear end of the shield machine 5 or the front end of the laying tube 12.
A lubricant injection pipe is attached to communicate with the lubricant injection pipe, and a valve 20 is provided at an appropriate position.

21 is the pipe body 1 from the starting shaft 2 to the reaching shaft 22
A mixer installed in the starting shaft 2 after or at the time of laying the pipe 2 from the pump 23.
4, a hardenable material made of a self-hardening material is injected into the space 16.

Note that the cylindrical impermeable membrane 6 is formed to have a slightly larger diameter than the outer diameter of the shield device 5.

Now, while excavating the ground with the excavation part 8 of the shielding machine 5, the self-hardening material 11, which is pumped at a predetermined pressure by the injection pump, is pumped through the valve 10 and the injection pipe 9 to the outer periphery of the shielding machine 5 and the ground. 1, and presses the rear end of the tube 12 together with the shield machine 5 in the shaft 2.
2 is propelled, the impermeable membrane 6 is paid out from the impermeable membrane storage section 7 of the shielding machine 5 and covers the tube body 12. At this time, since the self-hardening material 11 is injected from the skin plate 5a of the shielding machine 5 through the injection pipe 9 between the ground 1 and the outer periphery of the shielding machine 5, even if the ground is gravel ground, the self-hardening material 11 The sand inside acts as a plugging material,
Smooth the surface of the excavated ground by closing the gaps between sand and gravel. Further, even if a part of the ground collapses during excavation by the cutter of the shielding machine 5 and a recess 27 is formed on the inner peripheral surface of the excavated ground, the recess 27 is filled with the self-hardening material 11. Therefore, the impermeable membrane 6
does not protrude into the concave portion 27, and therefore, the water-impermeable membrane 6 will not be damaged despite the pressure of the slipping material, which will be described later.

Next, a lubricant 25 such as a bentonite solution is injected into the space 16 between the impermeable membrane 6 and the pipe body 12 through the injection pipes 17 and 19 from the rear end of the shield machine 5 or the front end of the pipe body 12 and the wellhead side. The space 16 is filled with a lubricant 25 under pressure to prevent the water-impermeable membrane 6 from sliding against the pipe body 12, and the degree of pressurization by the press-fit lubricant is greater than the sum of groundwater pressure and earth pressure. Pressure is applied to press the outer peripheral surface of the impermeable membrane 6 toward the excavated ground, thereby preventing the collapse of the ground 1 via the self-hardening material 11 filled between the impermeable membrane 6 and the excavated ground.

The lubricant 25 may be a highly viscous aqueous solution containing bentonite as its main component or a highly absorbent polymer that becomes a spherical elastic body when it absorbs water (for example, acrylic acid, etc.).
A spherical elastic body made by adding water to vinyl alcohol copolymer is used.

When a highly viscous aqueous solution is used as the lubricant, the lubricant 25 also moves forward as the pipe body 12 moves forward, and the pressure due to the lubricant 25 decreases inside the space 16 on the shaft side. Pressure reduction can be eliminated by simultaneously injecting lubricant from the wellhead 4 side.

In addition, since the spherical elastic body made by adding water to a superabsorbent polymer maintains its spherical shape even against external pressure, a bearing effect occurs between the water-impermeable membrane 6 and the tube 12 when the tube 12 moves. Friction can be significantly reduced, and the distance over which the intermediate body 12 can be propelled can be increased.

In this way, while injecting the self-hardening material at a constant pressure into the space between the impermeable membrane 6 or the skin plate 5a of the shielding machine 5 and the ground 1, the space between the impermeable membrane 6 and the outer periphery of the pipe body 12 is While injecting lubricant at a constant pressure, the shield machine 5 is dug, and the pipe bodies 12 are successively added to cover the pipe bodies 12 with an impermeable membrane 6, and the rear end of the shield machine 5 (front end of the pipe body) is When the shield machine 5 reaches the reaching shaft 22, the shield machine 5 is kept in a stopped state.

Next, in this state, the lubricant 25 press-fitted into the space 16 is a non-hardening liquid, and if this liquid escapes, the ground may sink or the pipe body 1
2 may move up and down, so the lubricant is replaced with a hardening material.

The hardenable material may be the same material as the self-hardening material injected from the shielding machine 5 earlier, or may be a mortar made by mixing cement and sand, or a material made by adding bentonite to this mortar. In short, any material that is in a liquid state at the time of injection and hardens after a certain period of time after injection is sufficient. Incidentally, it is preferable to mix bentonite into the mortar because the mortar will flow easily into the pipe or hose during injection.

The curable material is injected between the impermeable membrane 6 and the pipe body 12 by installing a mixer 21 in the shaft 2 and driving a pump 23 to inject the curable material through a pipe 24 connected to the injection pipe 17, as shown in FIG. At this time, the curable material is not necessarily injected from one location on the shaft side, but may be injected from the inner surface of the tube body 12 through an appropriate hole.

When the curable material 26 is injected between the impermeable membrane 6 and the pipe body 12 in this manner, the lubricant 25 flows out from the pipe 16 on the shield machine 5 side and is replaced by the curable material 26.

Alternatively, the lubricant extruded by injecting the curable material 26 may be put into a mixer, and cement or sand may be added thereto and stirred to be used as a curable material, which saves material and is economical. It is.

After the hardenable material 26 filled in the space 16 hardens, the shielding machine 5 is removed.

(Effects of the Invention) As described above, according to the method for coating an underground pipe body with an impermeable membrane of the present invention, while covering the pipe body to be laid with the impermeable membrane, a lubricant is applied between the pipe body and the impermeable membrane. Since the water is injected between the pipes, the impermeable membrane is prevented from coming into sliding contact with the pipe body and there is no risk of damage, and groundwater is reliably prevented from flowing into the pipe body, and the propulsion resistance of the pipe body is reduced, making it smoother. In addition, since a self-hardening material is injected between the impermeable membrane and the ground, even if a portion of the ground collapses due to gravel, the material will not fill the depressions. This makes it possible to reliably prevent the ground from collapsing, and also to prevent the impermeable membrane from sinking into the recesses, thereby preventing its damage.

Furthermore, after the pipe is laid, a hardening material is injected between the pipe and the impermeable membrane to replace the lubricant, so the hardenable material can prevent ground subsidence; This completely prevents it from penetrating into the ground, eliminating loss of use.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; Fig. 1 is a simplified longitudinal side view of a state in which the tube is propelled while injecting a self-hardening material and a lubricant, and Fig. 2 shows a case in which the lubricant is replaced with a curable material. FIG. 1...Ground, 2...Shaft, 5...Shield machine,
6... Impermeable membrane, 7... Storage section, 11... Self-hardening material, 12... Pipe body, 13... Pressing device, 16
... Space part, 9, 17, 19 ... Injection pipe, 2
5...Lubricant, 26...Hardenable material.

Claims (1)

[Claims] 1 In a propulsion method in which a shield machine excavates the ground and a pipe body following the shield machine is pressed by a pressing device installed in a shaft to lay the pipe body in the ground, a cylindrical impermeable pipe stored in the shield machine is used. After fixing the end of the membrane to the shaft wall, the tube body is joined to the rear end of the shield machine and pushed forward to cover the tube body with an impermeable membrane, while creating a self-hardening structure between the impermeable membrane and the excavated ground. While injecting a consolidation material and injecting a lubricant between the impermeable membrane and the outer surface of the pipe, the pipes are successively joined and propelled as the shield machine excavates, and then, after the series of pipes has reached the destination shaft, A method for coating a buried pipe body with an impermeable membrane, which comprises injecting a curable material between the pipe body and the impermeable membrane to replace the lubricant.