JP4909444B1 - Tunnel backfill injection method and injection device used therefor - Google Patents

Abstract

[PROBLEMS] To stabilize the tunnel structure rationally and economically, such as by drastically reducing the amount of filler injected while maintaining soundness by devising the filler injection means. A tunnel backfill injection method and an injection device used in the method are provided.
SOLUTION: A plurality of injection holes 4 penetrating a lining concrete 1 toward a cavity 3 are arranged at the top end portion of the lining concrete 1 and positions on both sides in the circumferential direction Y, and in a tunnel axial direction X. When the filler 5 is injected from the lower and higher rows of injection holes 4a and 4b into the higher row of injection holes 4c among the plurality of injection holes 4. The filler 5 is quantitatively injected into the lower rows of the injection holes 4a and 4b other than the injection hole 4c provided in the upper hole 4c, and the filler 5 is pressure-injected only into the injection hole 4c provided in the top end portion, whereby the cavity 3 is injected into almost the whole.
[Selection] Figure 1

Description

  The present invention relates to a tunnel backfill injection method for reinforcing and stabilizing a tunnel structure by injecting and filling a cavity formed between a back surface of a lining concrete and a ground, and an injection used in the method. It belongs to the technical field of equipment.

  A tunnel may have a cavity (gap) between the back of the lining concrete and the natural ground. If there is a hollow part, there is a risk of causing looseness in the natural ground, and there are problems such as local uneven load (bias pressure) acting and cracking in the lining concrete. Therefore, various techniques for reinforcing and stabilizing the lining concrete and the ground, and eventually the tunnel structure by injecting a filler into the cavity (back injection) have been disclosed (for example, Patent Documents). 1-4).

  However, the techniques according to Patent Documents 1 to 4 are inventions that focus on the material of the filler, the injection tube and its mounting jig, or a local (limited) filling method, etc. The present invention focused on tunnel backfill injection methods (mainly, the arrangement of injection holes to be drilled in lining concrete, injection procedure into injection holes, injection means) Absent.

By the way, there is a manual that specifically proposes a tunnel back-injection method in the case where there is a planar spread in the cavity formed between the back surface of the lining concrete and the natural ground (Non-Patent Documents 1 to 3). reference). Each manual describes in detail the arrangement of the injection holes drilled in the lining concrete, the injection procedure into the injection holes, the injection means, and the like.
In the following, based on each manual, an outline of the tunnel back-injection method commonly used in recent years will be briefly described.

1) A plurality of injection holes are arranged in a staggered pattern with a total of 3 to 13 rows (especially 3 rows) in a staggered pattern, with the same number of left and right at the top end of the lining concrete and the positions on both sides in the circumferential direction. Provide.
2) As a general rule, the injection procedure is carried out by pushing one row at a time from the lower row of injection holes in the tunnel longitudinal direction to the higher row of injection holes.
3) The injection means performs pressure injection based on about 0.2 MPa in all of the plurality of injection holes. Filling confirmation is performed while simultaneously monitoring the injection volume and injection pressure.
4) When using foamed urethane (non-cement type) as the filler, the injection device has previously been injected into the injection hole with its lower end (mouth) protruding (exposed) from the surface of the lining concrete. Inserted, caulked, set the injection tube, and in the operation of injection, the injection hose was connected to the mouth of the injection tube, and the connection portion was simply tightened with a fastening member such as a wire To do.

By the way, in Non-Patent Document 2, if the filler is pressure-injected (so-called complete filling) into the cavity within the range of 90 degrees around the top edge of the lining concrete for every casting span, the tunnel structure is stabilized. Since March 2007, when the Non-Patent Document 2 was issued, a method of pressure-injecting a filler into a cavity within a range of 90 degrees around the top end has been recommended. Yes.
By the way, since the non-patent document 1 issued before this time did not show the range of 90 degrees around the top end, the entire range of the cavity formed between the back surface of the lining concrete and the natural ground It was understood that it was necessary to pressure-fill the (overall) filler.

Japanese Patent No. 3492501 JP 2003-27891 A JP 2007-16504 A JP 2007-16504 A “Public Works Research Institute Road Tunnel Deformation Countermeasures Manual (Draft)” ISSN 0386-5878 Civil Engineering Research Laboratories Material No. 3877, National Public Works Research Institute Basic Road Technology Research Group (Tunnel Team), February 2003, 114-118 "Guide for tunnel repair method (draft)" Ministry of Land, Infrastructure, Transport and Tourism Chugoku Regional Development Bureau, March 2007, pages 21-23 “Tunnel Repair / Renovation Manual (Draft)” Geofronte Research Society New Technology Mutual Use Subcommittee Tunnel Renovation / Repair WG, March 14, 2008, pp. 194-194

A) From Non-Patent Document 2, although there is recognition that the tunnel structure can be stabilized if the filler is pressure-injected into the cavity within the range of 90 degrees around the top edge of the lining concrete, At present, many methods of pressure-injecting a filler into the entire range (the whole) of the hollow portion formed between the back surface of the lining concrete and the natural ground are implemented.
However, there is a concern that the pressure injection may inject the filler densely into many (infinite) small gaps generated in the natural ground.
This is because it is known from the results of experiments conducted by the applicant that the soundness of core removal confirmation and the like is investigated that the presence or absence of the small gap does not affect the stabilization of the tunnel structure. Therefore, the cost required for the filler injected not only into the cavity but also into the small gap is useless and uneconomical.

That is, not only the method of pressure-injecting the filler into the entire range of the cavity, but also the method of pressure-injecting the filler while limiting to the cavity within the range of 90 degrees around the top end, As a result of many fillers being densely injected into a large number of small gaps formed in the mountain, the final injection amount of filler is excessively larger than necessary with respect to the cavity volume obtained from the injection hole (cutting hole). There was a problem of economy.
Hereinafter, an implementation result by the present applicant, in which a filler is pressure-injected in the entire range of the hollow portion, will be described as an example.

When the cavity volume is 78 (m ³ ), the final injection amount is 193 (m ³ ).
When the cavity volume is 217 (m ³ ), the final injection amount is 525 (m ³ ).
When the cavity volume is 541 (m ³ ), the final injection amount is 1,136 (m ³ ).
When the cavity volume is 1,231 (m ³ ), the final injection amount is 3,292 (m ³ ).
When the cavity volume is 1,487 (m ³ ), the final injection amount is 3,561 (m ³ ).
On average, it was found that about 2.45 times as much filler as the cavity volume determined from the injection hole was injected.

Moreover, since pressure injection is performed while simultaneously monitoring the injection amount and the injection pressure (for example, 0.2 MPa), precise work is required and takes time and effort. Therefore, injecting the filler into all the injection holes by pressure injection is complicated, and there is a problem that the injection operation is prolonged.
Therefore, it is necessary to say that the conventional tunnel back-injection method based on the manuals described above is irrational and uneconomic based on the above-described experimental results and implementation results by the applicant.

B) Next, paying attention to the injection device, conventionally, during the injection operation, an injection hose was connected to the mouth of the injection tube, and the connecting portion was simply tightened with a fastening member such as a wire.
Therefore, particularly when pressure injection is performed, there is a problem that the injection hose comes off from the mouth of the injection pipe due to a sudden rise in pressure, etc., and the unfoamed material (filler) being injected leaks out. It was.
Since the unfoamed material is in a state where foaming is not completely completed, if the unfoamed material is scattered (dropped) on a passing vehicle, the adhesion is extremely strong and it is difficult to remove. Moreover, since the specific gravity is light (less than 0.03 g / cm ³ ), there is a concern that a traffic accident may occur when it is scattered in front of the driver. In addition, the injection work is delayed, and the cost required for the filler is wasted, which is uneconomical.

Moreover, since it sets in the state which exposed the lower end part (mouth | mouth) of the injection pipe from the lining concrete surface, the operation | work which cuts the said exposed part with a sander etc. after completion | finish of injection | pouring work is required, and takes time. In addition, this work has a problem that the working environment is deteriorated because the filler and the powder in the injection tube are scattered during cutting.
Furthermore, many conventional injection hoses do not have heat resistance. Therefore, when foaming urethane is used as the filler, heat (150 to 170 ° C.) is generated due to foaming of the urethane. As a result, the injection hose may be broken and the filler may leak out. The pressure resistance was not sufficient.

  The purpose of the present invention is to devise the filler injection means based on the experimental results of investigating the soundness of lining concrete, etc. by the applicant, and the results of implementation based on the prior art (each manual above), A tunnel back-injection method capable of rationally and economically stabilizing the tunnel structure, such as dramatically reducing the amount of filler injected while maintaining the soundness, and an injection device used in the method Is to provide.

As a means for solving the problems of the background art, the tunnel backfill injection method according to the invention described in claim 1 is characterized in that a filler is provided in a hollow portion formed between the back surface of the lining concrete and the natural ground. In the back injection method of the tunnel to be injected,
A plurality of injection holes through which the lining concrete is penetrated toward the hollow portion are provided at the top end portion of the lining concrete and positions on both sides in the circumferential direction thereof, and are arranged at intervals in the tunnel axis direction. ,
Among the plurality of injection holes, when the filler is injected from the low and high rows of injection holes into the high row of injection holes, the filler is applied to the low rows of injection holes other than the injection holes provided at the top end portion. The filling material is injected into almost the entire cavity by injecting a constant amount and pressure-injecting the filling material only into the injection hole provided in the top end portion.

  The invention described in claim 2 is the tunnel back-injection method according to the invention described in claim 1, wherein the plurality of injection holes are the same in the left and right positions at the top end portion of the lining concrete and the positions on both sides in the circumferential direction. It is characterized by being arranged in a total of 3 to 13 rows each.

The invention described in claim 3 is the tunnel back-injection method according to the invention described in claim 1 or 2, wherein the plurality of injection holes are arranged at the top end portion of the lining concrete and the positions on both sides in the circumferential direction thereof. It is a case where the same number of left and right is arranged in a total of 5 to 13 rows,
Among the plurality of injection holes, the filling material is quantitatively injected in order from the lower row of injection holes provided in one side portion to the higher row of injection holes, with the injection hole provided at the top end as a boundary. The filler is quantitatively injected in order from the lower row of injection holes provided in the portion to the higher row of injection holes, and then the filler is pressure-injected only in the injection holes provided in the top end portion.

  According to a fourth aspect of the present invention, in the tunnel back-injection method according to any one of the first to third aspects, the plurality of injection holes are substantially the same as when the lining concrete is viewed from the plane direction. It is arranged in a staggered pattern.

  The invention described in claim 5 is the tunnel back-injection method according to any one of claims 1 to 4, wherein the filler has a foaming ratio of 12, 30 or 40 times. It is made of urethane.

  According to a sixth aspect of the present invention, in the tunnel back-injection method according to any one of the first to fifth aspects, the method is performed for each casting span of the lining concrete.

An injection device according to the invention described in claim 7 is an injection device used for the tunnel back-injection method according to any one of claims 1 to 6,
The injection device comprises an injection tube inserted into the injection hole, an injection hose, and a socket and a plug for connecting the injection tube and the injection hose in series,
A socket connected to the lower end of the injection tube is fitted into the insertion port of the injection hole and is erected so as to penetrate the injection tube to the injection hole, and a plug is connected to the socket and injected into the plug. When the hose is connected, the injection pipe and the injection hose are connected in series, and the filling material is injected into the cavity formed between the back surface of the lining concrete and the ground. .

According to the tunnel back-injection method according to any one of claims 1 to 6, among the injection holes arranged in a plurality of rows (3 to 13 rows), the highest row (that is, the top and bottom) in the tunnel longitudinal direction. Since pressure injection is performed only for the injection holes provided in the end portion and quantitative injection is performed for the injection holes in the other low rows, the following effects are obtained.
1) Since precise work is required and time-consuming pressure injection can be limited only to the injection holes provided at the top end, the injection work is less than the conventional technique in which pressure injection is performed for all injection holes. It can be done promptly. Therefore, it is highly economical because it can contribute to shortening the construction period.
2) Since the portion of the pressure injection that is highly likely to be filled with the filler in a large number of small gaps in the natural ground can be limited to the injection hole provided at the top end portion, the filling amount is greatly increased. Can be reduced and it is very economical.
3) The soundness of lining concrete, etc. (management data for confirmation of cavity filling, core removal test, endoscopic inspection, etc.) is equivalent to that of the conventional method in which pressure is injected into all injection holes. Can be maintained, and the tunnel structure can be stabilized.

According to the injection device used in the tunnel back-injection method according to claim 7, the following effects are produced.
4) Since the injection tube and the injection hose can be firmly connected in series via a socket and a plug, even if a sudden pressure rise occurs when pressure is injected, injection from the mouth of the injection tube There is no risk of the hose (or socket) coming off. Therefore, the unfoamed material (filler) being injected does not leak out, so that it is excellent in workability, economy, and safety.
5) When the socket is removed from the lower end of the injection tube after the completion of the injection operation, the lower end of the injection tube inevitably fits in the injection hole (see FIG. 7), so the lower end of the injection tube as in the conventional method is cut. You can save time and effort. Moreover, since it can transfer to the coating operation | work which plugs up the lower end opening part of an injection hole smoothly, workability | operativity is good. Furthermore, since there is no possibility that the filler and the powder in the injection tube will be scattered during cutting, the working environment will not be deteriorated.
6) In addition, work efficiency can be further improved by using a material having heat resistance and pressure resistance for the injection hose or the injection pipe.

A is an elevation view schematically showing a tunnel to which the tunnel backfill injection method according to Example 1 is applied, and B is a plan view schematically showing a hollow portion of lining concrete. 1A is an elevation view schematically showing a filling situation in which a filler is quantitatively injected into the cavity on the back surface of the lining concrete according to FIG. 1, and B is a plan view schematically showing the filling situation. It is. 2A is an elevation view schematically showing a filling state in which a filler is further quantitatively injected into the cavity of the back surface of the lining concrete according to FIG. 2, and B is a plan view schematically showing the filling state. FIG. FIG. FIG. 3A is an elevation view schematically showing a filling situation in which a filler is further pressure-injected into the cavity on the back surface of the lining concrete according to FIG. 3, and B is a plan view schematically showing the filling situation. FIG. It is the elevation which showed the injection device used for the back injection method of the tunnel concerning the present invention. FIG. 6 is an exploded view of the injection device according to FIG. 5. It is the elevation which showed the state which removed the socket after completion | finish of the injection | pouring operation | work of a filler. It is the elevation which showed roughly the tunnel to which the tunnel back injection method concerning Example 2 is applied. It is the top view which showed roughly the cavity of the lining concrete which concerns on FIG. FIG. 9 is an elevation view schematically illustrating a filling state in which a filler is quantitatively injected into a cavity on the back surface of the lining concrete according to FIG. 8. It is the top view which showed roughly the said filling condition which concerns on FIG. FIG. 11 is an elevation view schematically showing a filling state in which a filler is further quantitatively injected into the cavity on the back surface of the lining concrete according to FIG. 10. FIG. 13 is a plan view schematically illustrating the filling state according to FIG. 12. FIG. 13 is an elevation view schematically illustrating a filling state in which a filler is further pressure-injected into a cavity portion on the back surface of the lining concrete according to FIG. 12. FIG. 15 is a plan view schematically illustrating the filling state according to FIG. 14. It is the table | surface which put together the experimental result by this applicant. It is the graph which put together the experimental result concerning FIG.

A tunnel backfill injection method according to the present invention is a tunnel backfill injection method in which a filler is injected into a cavity formed between the back surface of a lining concrete and a natural ground. A plurality of injection holes penetrating the concrete are provided at the top end portion of the lining concrete and the positions on both sides in the circumferential direction thereof, and are arranged at intervals in the tunnel axis direction, of the plurality of injection holes. When the filler is injected from the low and high rows of injection holes into the high row of injection holes, the filler is quantitatively injected into the low rows of injection holes other than the injection holes provided in the top end, The filler is injected into almost the entire cavity by pressure-injecting the filler only into the injection hole provided in the portion (the invention according to claim 1).
In short, this tunnel back-injection method requires precise work, takes time, and places pressure injection where there is a high risk that the filler will be infused into many small gaps in the ground. Is limited only to the injection holes provided in the highest row (that is, the top end) of the height in the tunnel longitudinal direction, and by quantitatively injecting the filler into the injection holes in the lower row excluding the injection holes, It is based on the technical idea to stabilize the lining concrete, ground, and eventually the tunnel structure very rationally and economically.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a tunnel backfill injection method and an injection device used in the method according to the present invention will be described below with reference to the drawings.

1 to 4 schematically show a tunnel back-injection method according to the first embodiment.
This tunnel back-injection method is a method in which a filler 5 is injected into the cavity 3 formed between the back surface of the lining concrete 1 and the ground 2, and the lining concrete 1 is directed toward the cavity 3. A plurality of (9 in the illustrated example for each casting span S) are inserted through the top end of the lining concrete 1 and at positions on both sides in the circumferential direction, and spaced in the tunnel axial direction X. When the filler 5 is injected from the low and high rows of injection holes 4 into the high rows of injection holes 4 among the plurality of injection holes 4, the injection holes provided at the top end portion are provided. A filling material 5 is quantitatively injected into the injection holes 4a and 4b in the lower rows other than 4c, and the filling material 5 is pressure-injected only into the injection holes 4c provided in the top end portion, so that almost the whole of the cavity 3 is injected. Filler 5 is injected (invention of claim 1).
As shown in FIG. 5, the means for injecting the filler 5 into the injection hole 4 (4a to 4c) is performed using an injection device 10 that is set to penetrate the injection hole 4. A specific configuration of the injection device 10 will be described later.
Incidentally, the injection hole 4c provided in the top end is provided at a position (near position) slightly shifted from the tunnel top (top). This is due to problems with vehicle traffic regulations that must not be.

In addition, the injection hole 4 which concerns on the present Example 1 is the space | interval of about 1500-1700mm by the same number (one line) left and right in the position of the top end part of the lining concrete 1 and its circumferential direction Y (refer FIG. 1B etc.) both sides. However, the present invention is not limited to this. Depending on the size of the cavity 3 and the size of the tunnel (empty cross-sectional area in the tunnel), the design can be appropriately changed between 3 and 13 rows in the circumferential direction (Y) of the lining concrete 1. Incidentally, in Example 2 to be described later, an example in the case of arranging in 5 rows is shown.
Accordingly, the injection holes 4 (diameter (φ) = about 28 to 30 mm) according to the first embodiment are implemented by providing a total of nine in a staggered pattern when the lining concrete 1 is viewed from the plane direction. However, the number of drilled holes is not limited to this. However, it is preferable to provide the adjacent injection holes 4 with an interval of about 1500 to 1700 mm.
Although the placing span S of the lining concrete 1 according to the first embodiment is 10.5 m, it may be implemented at 6 m, 9 m, or 12 m.
The filler 5 preferably has a low specific gravity and a high expansion ratio. Incidentally, in the first embodiment, foamed urethane having a foaming ratio of 40 times is used, but the foaming ratio can also be implemented by 12 or 30 times foamed urethane. Since the urethane foam has a property of solidifying (curing) rapidly in about 40 to 60 seconds, there is no loss during construction and workability is good.

The tunnel back-injection method according to the first embodiment is specifically performed by the following method.
First, as schematically shown in FIGS. 2A and 2B, the injection holes 4a ₁ → 4a ₂ → 4a are formed along the tunnel axis direction X in the left injection hole 4a of the low and high injection holes 4a and 4b. A fixed amount of filler 5 is injected in the order of ₃ .

The above-mentioned fixed injection is a predetermined injection hole regardless of whether or not the outflow (leakage) of the filler 5 is confirmed to the adjacent injection holes (for example, 4a ₂ , 4c ₁ ). (For example, 4a ₁ ) is a method for ending the injection work, and the filling amount is set by a widely used method such as a drilling measurement result of the injection hole (for example, 4a ₁ ) at the time of construction. . The same technical idea applies to Example 2 below.

Next, as schematically shown in FIGS. 3A and 3B, the filler 5 is quantitatively injected into the right injection hole 4 b in the order of the injection holes 4 b ₁ → 4 b ₂ → 4 b ₃ along the tunnel axis direction X.

Thereafter, as schematically shown in FIGS. 4A and 4B, the injection holes 4c in the highest row (the top end) of the height are arranged in the order of injection holes 4c ₁ → 4c ₂ → 4c ₃ along the tunnel axis direction. By filling the filler 5 with pressure, the filler 5 is injected into almost the entire cavity 3 (entire area).

  The pressure injection is performed by a technique substantially similar to the technique employed in the conventional backfill injection method. That is, the injection operation is performed while simultaneously monitoring the injection amount and the injection pressure. The lining concrete 1 is managed so that a pressure of about 0.2 MPa or more is not applied. In addition, the lining concrete 1 is monitored so as not to cause a new deformation such as a crack. In this way, when a pressure of about 0.2 MPa or more is applied to the lining concrete 1, the injection operation is immediately stopped and the injection operation to the next injection hole is performed. The same technical idea applies to Example 2 below.

  The above work process is repeated for every placement span (or even a plurality of spans) of the lining concrete 1 to fill almost the entire cavity 3.

In the first embodiment, the injection operation is started from the left injection hole 4a among the injection holes 4a and 4b in the lower row, but may be started from the right injection hole 4b.
In addition, when the lining winding thickness is thin and the lining concrete 1 is deformed by a biased (one-sided) filler and a new crack may occur, left and right alternating (4a ₁ → 4b ₁ → 4a ₂ → 4b ₂ →...) And a balanced injection procedure may be performed.

Next, the injection device 10 used for the tunnel back-injection method according to the first embodiment will be described.
As shown in FIG. 5, the injection device 10 has an injection tube 11 inserted into the injection hole 4, an injection hose 12, and the injection tube 11 and the injection hose (stir hose) 12 connected in series. Socket (for example, a known faucet socket) 13 and a plug (for example, a plug for faucet socket) 14.
In this embodiment, as shown in FIG. 6, the socket 13 into which the lower end portion of the injection tube 11 is inserted and connected is inserted into the insertion port of the injection hole 4 drilled in advance, and the injection tube 11 is injected. It stands up so as to penetrate through the hole 4. In this state, when actually injecting into the injection hole 4, the plug 14 connected to the injection hose 12 is screwed (or fitted) into the socket 13 to be firmly connected. If it does so, the said injection | pouring pipe | tube 11 and the injection | pouring hose 12 will be connected in series, and the operation | work which inject | pours the filler 5 into the cavity 3 produced between the back surface of the lining concrete 1 and the natural ground 2 can be performed ( (See FIG. 5). Needless to say, the plug 14 is first screwed (or fitted) into the socket 13 and firmly connected, and then the injection hose 12 is connected to the plug 14.

The socket 13 includes an upper small-diameter cylindrical portion and a lower large-diameter cylindrical portion, and the lower end portion of the injection tube 11 is deeply and closely inserted into the upper small-diameter cylindrical portion. The inner diameter of the small-diameter cylindrical portion is formed in a narrow taper shape from the upper side to the lower side, and the lower end portion of the injection tube 11 cannot be easily detached.
In the socket 13 according to this embodiment, the outer diameter of the upper small-diameter cylindrical portion is slightly smaller than the hole diameter (about 28 to 30 mm) of the injection hole 4 and is perpendicular to the outer peripheral surface of the lower large-diameter cylindrical portion. The provided ribs 13a are fitted into the hole inner surface of the lower end opening of the injection hole 4 with a configuration in which a frictional force (fixing force) is obtained by biting in about several mm to 10 mm. A female screw is cut on the inner peripheral surface of the large-diameter cylindrical portion of the socket 13, and a male screw formed on the upper portion (insertion portion) of the plug 14 is screwed and fixed.
In addition, it is preferable for the injection work that the upper end of the injection tube 11 is positioned about 50 mm away from the natural ground 2 (see FIG. 7).
Further, in the injection hose 12, vinylon fibers (φ = 0.1 to 0.2 mm) are incorporated in a net shape in order to improve pressure resistance. It is preferable to use a material having heat resistance for the injection tube 11 and the injection hose 12.
Although illustration is omitted, a pressure gauge is provided when pressure injection is performed. Incidentally, reference numeral 15 in the figure indicates that the gap between the outer peripheral surface of the injection tube 11 and the inner peripheral surface of the injection hole 4 is filled and the injection hole 4 flows backward before the filler 5 filled in the cavity 3 is solidified. A waste cloth that prevents leakage toward the inside is shown. Reference numeral 16 denotes a hose band.

After finishing the injection operation, the socket 13 is pulled out from the injection tube 11 and only the injection hose 12 and the plug 14 are moved to the next injection hole 4. The plug 14 is connected to the socket 13 to which the injection tube 11 is connected in order (see FIG. 6 for assistance). The socket pulled out from the injection tube 11 is stocked.
On the other hand, the injection operation is completed, the injection tube 11 from which the socket 13 has been pulled out is buried, and the lower end opening of the injection hole 4 is coated (sealed) with an epoxy resin 17 as shown in FIG. .

8 to 14 schematically show the tunnel back-injection method according to the second embodiment.
In the second embodiment, the plurality of injection holes 4 are arranged in three rows in the circumferential direction Y of the lining concrete 1 while the first embodiment is arranged in five rows. Is mainly different.
Note that if the plurality of injection holes 5 are arranged in five rows, the variation of the injection procedure is greatly expanded. Therefore, in the illustrated example, in consideration of the speed (continuity) of the injection operation and the relaxation of the vehicle traffic regulation in the tunnel premises, the injection procedure is carried out with the most rational injection procedure.

That is, in the tunnel backfill injection method according to the second embodiment, a plurality of injection holes 4 (17 in the illustrated example for each placement span S) penetrating the lining concrete 1 are formed on the lining concrete 1. The same number of left and right (two rows) is provided at the top end and the positions on both sides in the circumferential direction, aligned in a total of five rows, and the injection holes provided at the top end among the plurality of injection holes 4 provided in the five rows. 4e is used as a boundary to sequentially inject the filler 5 from the lower row of injection holes 4a provided on one side portion (left side in the illustrated example) into the higher row of injection holes 4c, and then to the other side portion (right side in the illustrated example). ) By sequentially injecting the filler 5 from the lower row of injection holes 4b to the higher row of injection holes 4d, and then pressure-injecting the filler 5 only into the injection holes 4e provided at the top end, The filler 5 is injected into almost the entire cavity 3 (the invention according to claim 3).
The means for injecting the filler 5 into the injection hole 4 (4a to 4e) is performed using the injection device 10 already described (see paragraphs [0035] to [0037]).

In addition, although the placement span S of the lining concrete 1 which concerns on this Example 2 is 10.5m similarly to the said Example 1, it may implement at 6m, 9m, or 12m.
The injection holes 4 (diameter (φ) = about 28 to 30 mm) according to the second embodiment are implemented by providing a total of 17 in a staggered pattern when the lining concrete 1 is viewed from the plane direction. Of course, the number of perforations is not limited to this. However, it is preferable to provide the adjacent injection holes 4 with an interval of about 1500 to 1700 mm.
Further, as in the first embodiment, the filler 5 is preferably urethane having a foaming ratio of 40 times, but can also be implemented by foaming urethane having a foaming ratio of 12 times or 30 times.

The tunnel back-injection method according to the second embodiment is specifically performed by the following method.
First, as schematically shown in FIGS. 10 and 11, a tunnel is formed in a low row of injection holes 4a provided on one side portion (left side in the illustrated example) with an injection hole 4e provided at the top end as a boundary. Along the axial direction X, the filler 5 is quantitatively injected in the order of injection holes 4a ₁ → 4a ₂ → 4a ₃ . Next, the filling material 5 is quantitatively injected in the order of the injection holes 4c ₁ → 4c ₂ → 4c ₃ → 4c ₄ along the tunnel axis direction X into the adjacent high rows of injection holes 4c.
The significance of injecting into the adjacent injection hole 4c after injecting the injection hole 4a, that is, the procedure of injecting into the corresponding injection hole 4b after injecting the injection hole 4a is not employed. This is because it is possible to avoid complication of vehicle traffic regulation.

Next, as schematically shown in FIGS. 12 and 13, injection holes 4 b ₁ → 4 b are formed along the tunnel axis direction X in the lower row of injection holes 4 b provided on the other side portion (right side in the illustrated example). the filler 5 in the order of ₂ → 4b ₃ quantified injection. Next, the filling material 5 is quantitatively injected in the order of the injection holes 4d ₁ → 4d ₂ → 4d ₃ → 4d ₄ along the tunnel axis direction X into the adjacent high rows of injection holes 4d.

Thereafter, as schematically shown in FIGS. 14 and 15, the filler 5 is formed in the order of the injection holes 4e ₁ → 4e ₂ → 4e ₃ along the tunnel axis direction in the injection hole 4e provided in the top end portion. The filler 5 is injected into almost the entire cavity 3 by pressure injection.
The above work process is repeated for every placement span (or even a plurality of spans) of the lining concrete 1 to fill almost the entire cavity 3.

In the second embodiment, the injection operation is started from the leftmost injection hole 4a in the drawing, but may be started from the rightmost injection hole 4b.
If the lining winding thickness is thin and the lining concrete 1 is deformed by the bias of the filler and there is a possibility that a new crack may occur, left and right alternating (4a ₁ → 4b ₁ → 4c ₁ → 4d ₁ → -)) And may be carried out in a balanced injection procedure.
In short, the procedure of injecting the filler 5 into the injection hole 4 is the best mode described in the illustrated example, but the injection injected into the injection holes 4e (4e ₁ to 4e ₃ ) provided at the top end portion. As long as the material 5 is configured to be dammed with the filler 5 that has been preliminarily injected into the injection holes 4c and 4d on both sides thereof, implementation in various variations is possible.

Furthermore, in the second embodiment, the plurality of injection holes 4 are arranged in the same number (two rows) at the top end portion of the lining concrete 1 and the positions on both sides in the circumferential direction, and arranged in a total of five rows. However, it is not limited to this.
Although illustration is omitted, for example, a plurality of injection holes 4 are arranged in a total of 7 rows, 3 rows on the left and right (or 4 rows, 5 rows or 6 rows) at the top end of the lining concrete 1 and the positions on both sides in the circumferential direction. (Or 9 rows, 11 rows, or 13 rows). Even in such a case, as in the second embodiment, the injection hole provided at the top end is used as a boundary, and is divided into one side part and the other side part. By filling a filling material into the injection hole in order, and finally injecting pressure into the injection hole provided at the top end, almost the entire cavity 3 can be filled.

Therefore, according to the tunnel backfill injection method according to the first and second embodiments, among the injection holes 4 aligned in the circumferential direction Y of the lining concrete 1 in a plurality of rows (particularly 3 to 13 rows). Since the pressure injection is performed only on the injection holes provided at the highest top and bottom of the tunnel in the longitudinal direction of the tunnel, and the quantitative injection is performed on the injection holes in the other low rows, the following effects are obtained.
1) Since precise work is required and time-consuming pressure injection can be limited only to the injection holes provided at the top end, the injection work is less than the conventional technique in which pressure injection is performed for all injection holes. It can be done promptly. Therefore, it is highly economical because it can contribute to shortening the construction period.
2) Since the portion of the pressure injection that is highly likely to be filled with the filler in a large number of small gaps in the natural ground can be limited to the injection hole provided at the top end portion, the filling amount is greatly increased. Can be reduced and it is very economical.
Incidentally, FIG. 16 shows a table of the results of unknown experiments by the applicant. The applicant has conducted 21 experiments. As a result, on average, the 21 experimental examples were found to fill almost the entire cavity portion 3 with a filling amount of about 1.26 times the cavity volume obtained from the injection hole 4. When the result of this experiment is graphed as shown in FIG. 17, the result is almost directly proportional to the accuracy of the experiment.
This is drastically reduced compared to the filling amount of the filler 5 which is approximately 2.45 times that of the conventional method in which all the injection operations for the injection holes are performed by pressure injection (see paragraph [0010] above). I understand. Specifically, for example, when the cavity volume is 1000 (m ³ ), the conventional method requires as much as about 2450 (m ³ ) filler 5, whereas according to the present invention, about 1260 (m ^3). ) Is sufficient, and is almost halved. In terms of costs, in some cases, a disparity of several hundred million yen may occur.
3) In addition, as a result of investigating the soundness of the lining concrete, etc. during the experiment of 2) and after the experiment (management data for confirming cavity filling, core removal test, endoscopic inspection, etc.) Although the numerical values and the like are omitted, it was found that the tunnel structure can be stabilized by maintaining the same as the conventional method.

  The embodiments have been described with reference to the drawings. However, the present invention is not limited to the illustrated examples, and includes a range of design changes and application variations that are usually made by those skilled in the art without departing from the technical idea thereof. I will mention that just in case.

DESCRIPTION OF SYMBOLS 1 Covering concrete 2 Ground mountain 3 Cavity part 4 Injection hole 5 Filling material 10 Injection instrument 11 Injection pipe 12 Injection hose 13 Socket 13a Rib 14 Plug 15 Waste 16 Hose band 17 Epoxy resin

Claims (7)

In the tunnel backfill injection method of injecting filler into the cavity created between the back of the lining concrete and the natural ground,
A plurality of injection holes through which the lining concrete is penetrated toward the hollow portion are provided at the top end portion of the lining concrete and positions on both sides in the circumferential direction thereof, and are arranged at intervals in the tunnel axis direction. ,
Among the plurality of injection holes, when the filler is injected from the low and high rows of injection holes into the high row of injection holes, the filler is applied to the low rows of injection holes other than the injection holes provided at the top end portion. A tunnel back-injection method, characterized by injecting a filler into almost the entire cavity by injecting a fixed amount and pressure-injecting the filler only into an injection hole provided at the top end.   2. The tunnel according to claim 1, wherein the plurality of injection holes are provided at the top end portion of the lining concrete and the positions on both sides in the circumferential direction so as to be arranged in a total of 3 to 13 rows in the same number of left and right. Backfill injection method. In the case where the plurality of injection holes are provided at the top end portion of the lining concrete and the positions on both sides in the circumferential direction, the same number of left and right, arranged in a total of 5 to 13 rows,
Among the plurality of injection holes, the filling material is quantitatively injected in order from the lower row of injection holes provided in one side portion to the higher row of injection holes, with the injection hole provided at the top end as a boundary. The filling material is pressure-injected only in the injection hole provided in the top end portion after quantitatively injecting the filling material in order from the low-row injection hole provided in the portion to the high-row injection hole. Or the tunnel back-injection method described in 2.   4. The tunnel backfill injection method according to claim 1, wherein the plurality of injection holes are arranged in a staggered pattern when the lining concrete is viewed from a plane direction. 5. .   The tunnel backfill injection method according to any one of claims 1 to 4, wherein the filler is made of urethane having a foaming ratio of 12, 30, or 40 times.   The tunnel back-injection method according to any one of claims 1 to 5, wherein the tunnel back-injection method according to any one of claims 1 to 5 is performed for each placement span of the lining concrete. An injection device for use in the tunnel back-injection method according to any one of claims 1 to 6,
The injection device comprises an injection tube inserted into the injection hole, an injection hose, and a socket and a plug for connecting the injection tube and the injection hose in series,
A socket connected to the lower end portion of the injection tube is fitted into the insertion port of the injection hole and is erected so as to penetrate the injection tube to the injection hole, and a plug is connected to the socket and injected into the plug. When the hose is connected, the injection pipe and the injection hose are connected in series, and the filling material is injected into the cavity formed between the back surface of the lining concrete and the ground. , Injection device.

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