JPS6360199B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a backside injection method for underground structures such as existing tunnels.

[Prior art]

Conventionally, when performing backfill injection from the inside of underground structures such as tunnels to the back of the structure, or injection of chemical solutions to strengthen the ground, the equipment shown in Figures 1 and 2 was generally used. It has been adopted. In other words, the device shown in Fig. 1 has a casing c fixed in an injection hole a formed in the ground with cement milk d, etc., and a packing car e having a packing d on the inner peripheral surface connected to the casing c. Yes, injection hole a
After inserting the rock drill rod into the hole and drilling it to the required depth, insert the injection pipe f into the casing c.
The packing d of the packing car e is inflated to seal the injection hole a, and a chemical solution or the like is injected into the casing c by taking a reaction force.

In addition, the device shown in Fig. 2 installs a packing car e having a packing d on its outer periphery inside a drilled injection hole a, and expands the packing d to bring the packing d into close contact with the inner peripheral surface of the injection hole a. It fixes and seals the injection hole a, and takes a reaction force from the adhesion between the packing d and the inner peripheral surface of the injection hole a, and injects a chemical solution, etc. into the injection hole a from the injection pipe f inside the packing car e. It is press-fitted.

However, when performing backside injection for repair or the like in existing underground structures such as tunnels, problems arise with the above-described apparatus.

In other words, the following matters need to be considered for existing underground structures.

There are various facilities inside an underground structure depending on the purpose of use of the structure, and in the case of a tunnel, there is also operation of trains, automobiles, etc., and there is a space where various equipment for injection can be installed. very narrow,
small and limited.

Since it is fully expected that forced water pressure will exist on the back side of the structure, an injection device that can withstand this water pressure is required.

Most of the existing underground structures are actually in use, and if the injection device falls off during the injection work, it will cause a major accident and must be avoided at all costs.

It is undesirable for medicinal solutions to leak during the injection operation or for devices to be left behind after the entire operation is completed.

Therefore, in order to obtain a large reaction force, the device shown in FIG. 1 requires the casing c to be deeply inserted into the injection hole a and fixed, making it large and heavy and complicated to handle.

In addition, the device shown in Fig. 2 takes the reaction force by the frictional force between the packing d and the inner peripheral surface of the injection hole a, so a large reaction force cannot be obtained. In order to insert the injection hole into the hole a, a large-diameter injection hole a must be drilled, which is a troublesome operation.

Therefore, although the apparatus shown in FIGS. 1 and 2 can be used for the injection method during construction work, it is not suitable for the injection method for existing underground structures.

[Purpose of the invention]

This invention was made to improve the above-mentioned drawbacks, and the device used is small and lightweight, making it easy to install, allowing injection work to be performed even in a small space, and making it possible to perform the work safely. Another object of the present invention is to provide a backside injection method for underground structures such as existing tunnels, which allows for almost complete removal of various devices after all work is completed.

[Structure of the invention]

The back injection method for underground structures such as existing tunnels according to the present invention involves abutting a flange against the surface of the existing underground structure, fixing the flange to anchor bolts fixed to the structure, and forming a casing that is integrated with the flange. A packer is connected to the casing via a valve, and an injection nozzle is inserted from the packer into the injection hole communicating with the casing, and the reaction force is applied to the skeleton through the casing to inject the injection material into the underground structure. The above objective is achieved by dorsal injection.

〔Example〕

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

<1> Fixing the casing In the figure, 1 is the casing integrated with the flange, which is fixed to the framework of the existing underground structure. In this example, the back injection method according to the present invention was carried out in the case of performing back injection in a tunnel which is an underground structure, and a segment S was used as the frame. In the casing 1 shown in FIG. 3, a flange 12 having a curved surface 13 corresponding to the curvature of the inner surface of the segment S is formed on the outer periphery of one end of a cylindrical insertion portion 11.

A plurality of bolt holes are formed in the flange 12, and a male screw 14 is screwed on the outer periphery of the end opposite to the side where the flange 12 is formed.

Injection is normally performed through an existing injection port 2 of the segment S, and a plurality of anchor bolts 3 are installed around the injection port 2. In the embodiment, a wedge type anchor bolt 3 is used. In other words, a notch is formed at the tip in the direction of the center line, and a male thread is installed on the outer periphery of the other end.
A wedge is fitted into the notch. This anchor bolt 3 is inserted into a bolt attachment hole 31 drilled around the injection port 2 from the side where the wedge is fitted, and is driven, and the tip of the bolt 3 is expanded by the wedge and fixed. The wedge type anchor bolt 3 is fixed to the concrete segment S, which is more stable than the ground and can be expected to have a large pullout stress.

After fixing the anchor bolt 3, an insertion hole 41 is drilled in the center, and a packing 4 made of rubber or the like with a bolt hole formed around the insertion hole 41 corresponding to the anchor bolt 3 is attached to the segment of the anchor bolt 3. The protruding portion from S is inserted into the bolt hole and comes into contact with the inner circumferential surface of segment S. Furthermore, the protruding portion of the anchor bolt 3 from the segment S is inserted into a bolt hole formed in the flange 12 of the casing 1, and the nut 32 is screwed onto the male thread of the anchor bolt 3 to fix the casing 1.

<2> Attaching the police car etc. Attach the police car 5 etc. to the casing 1 fixed to the segment S which is the frame. Casing 1
A valve 6 for sealing the casing 1 is screwed onto the male thread 14 of the casing 1. As the valve 6, a known sluice valve or ball-cock valve can be used.

The valve 6 is further connected to a cylindrical packing 5 having a packing 51 attached to its inner peripheral surface by screwing.

At the opposite end of the packer 5 from the valve 6, there is a packer 5 which is screwed into a female thread screwed on the inner peripheral surface, has a rod insertion hole 52 formed in the center, and has a handle 53 protruding from the outer periphery. A fastener 54 is attached.

<3> Removing the plug Insert the plug removal tool 8, which has a socket 82 attached to the tip of the rod 81, into the packer 5, valve 6, and casing 1, and remove the plug 21 screwed into the existing inlet 2. If the plug 21 is firmly attached, remove it using an impact wrench or the like. Close valve 6 and turn on police car 5.
And once remove the plug removal tool 8.

<4> Injection work Insert the injection pipe 7 from the packing fastener 54 side of the packing car 5, and attach the injection plug 71. Thereafter, the packer 5 is connected to the valve 6 again, the valve 4 is opened, the injection pipe 7 is moved forward, and the injection plug 71 is screwed into the existing injection port 2.
A pot 72, an injection hose 73, and an injection pump 74 are connected to the rear end of the injection pipe 7. At this time, rotate the packing fastener 54 to remove the packing 51.
is expanded inward to close the gap between the injection pipe 7 and the packing 51, and preparation for injection work is completed. Thereafter, the injection pump 74 is driven to force-feed the injection material such as mortar, cement milk, water glass, or a polymeric chemical solution such as urethane, and the injection operation is started. This reaction force at the time of press-fitting is applied to the frame via the casing 1 fixed to the frame.

<5> Removing the device After injection is completed, close the pot 72 and disconnect the injection hose 73, then remove the pot 72.
2 and check for water leakage from the back of the tunnel, and if there is no water leakage, remove the injection pipe 7 and the police car 5. At this point, valve 6 is kept closed.

Open the valve 6 to check for water leakage, and if there is no water leakage, screw the plug 21 into the inlet 2 again and remove the valve 6.

After the above operations, after confirming that there is no need for reinjection, remove the nut 32 and remove the casing 1 and packing 4.

<6> Other embodiments In this invention, the casing 1 integrated with the flange is fixed to the framework of an underground structure as described above to absorb the reaction force during injection, but the casing 1 is simply anchored. If fixing with only the bolts 3 is insufficient, the following fixing means may be considered.

That is, in the embodiment shown in FIG.
A cylindrical fixing part 15 is formed by extending the insertion part 11 to the opposite side of the flange 12. This fixing part 15 is inserted into the fixing hole 22 drilled in the segment S, and mortar, synthetic resin, etc. 10 is filled between the outer periphery of the fixing part 15 and the inner periphery of the fixing hole 22, and the casing 1 is fixed to the segment S. It is set up. Further, the surroundings of the anchor bolts 3 are also filled with mortar or the like 10.

Since the fixed portion 15 is simply buried within the segment S, it is significantly shorter than a conventional casing, but the segment S is more stable than the ground and can be expected to generate a large pull-out stress.

Furthermore, as shown in FIG. 7, the pullout stress can be expected to be improved simply by filling the outer periphery of the anchor bolt 3 with mortar, synthetic resin, or the like.

〔Effect of the invention〕

Since the backside injection method for underground structures such as existing tunnels according to the present invention has the above-described configuration, the following effects can be obtained.

Because the casing is fixed to the segment, which is the framework of the underground structure, the casing is small and lightweight, making work extremely easy, and work can be done in a small space.

Because it is fixed to a segment that is more stable than soft ground, it is easy to attach the casing by fixing it with anchor bolts.

Because the casing is fixed to the segment, which is more stable than soft ground, a large and reliable pull-out stress can be expected, and the work can be carried out safely without detaching from the segment.

The device can be almost completely removed after injection work.

[Brief explanation of the drawing]

1 and 2 are longitudinal sectional views of a conventional injection device, and FIG. 3 is a longitudinal sectional view of an embodiment of a casing.
FIGS. 4 and 5 are longitudinal sectional views of one embodiment of the injection device used in the present invention, and FIGS. 6 and 7 are longitudinal sectional views of other embodiments of the casing. 1... Casing, 2... Inlet, 3... Anchor bolt, 4... Packing, 5... Packing car, 6... Valve, 7... Injection pipe, 8... Plug removal tool, 12... Flange.

Claims (1)

[Claims] 1 In the back injection method for existing underground structures such as tunnels, the flange is fixed to the anchor bolt that is fixed to the skeleton by abutting the flange on the surface of the underground structure, and the casing integrated with this flange is fixed to the skeleton. and connecting a packer to the casing via a valve, inserting an injection nozzle from the packer into an injection hole communicating with the casing,
A backside injection method for underground structures such as existing tunnels, which is characterized by taking a reaction force to the skeleton through the casing and injecting the injection material into the backside of the underground structure.