JP3267571B2 - Ground reinforcement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground reinforcement method such as a preloading method as a ground reinforcement method applied when excavating a tunnel or an underground cavity. In particular, the present invention relates to a mountain reinforcement method applicable under poor geological conditions.

[0002]

2. Description of the Related Art In conventional tunnel construction, terrain,
For geological reasons, the selection of wellheads on unstable slopes has been avoided, but in recent years there has been a tendency for wellhead locations to be planned irrespective of the location conditions and the quality of the geology. Conventionally, in places where geological conditions are poor, construction is performed with a small height, and a short forepoling is used to improve the independence of the face top, and a short resin bolt is used to improve the independence of the face mirror, In order to improve the stability of the mountain, in recent years, in such cases, the ground in front of the tunnel face has been used, and a long front receiving steel pipe has been used, and a long resin bolt has been used. Many mirror reinforcements are used.

[0003] These ground receiving methods and mirror reinforcement methods aim at suppressing the preceding loosening of the ground by restraining the ground in front of the face over a long length. It is characterized by a longer receiving length than the mirror reinforcement. As the drilling method using this long steel pipe, a ground support with each feature is implemented, and the mirror part reinforcement with a long resin bolt also uses resin bolts of various shapes. Has been implemented.

[0004] As an example of the ground front receiving method, there is an injection type long front receiving method (AGF method). In this AGF method, a drill jumbo or the like used for tunnel excavation is used to drill holes while expelling flushing water from a rock drill using a diameter expanding bit attached to the tip of a drilling rod or a ring bit attached to the tip of a steel pipe. A steel pipe having a length of about 3 m can be successively added while drilling a double pipe method to form a long steel pipe. Then, the steel pipe cast over the entire length is left in the ground, and a solidified material is injected into the surrounding ground through the steel pipe to improve the stability of the ground.

[0005] Fig. 7 is a schematic diagram showing the construction of a tunnel tip receiving work by the AGF method. In the AGF method, a steel pipe 1 is driven from the inside (the lower side in FIG. 7) of the steel support 2 of the tunnel face F by a drill jumbo or the like omitted in the drawing. At the time of placing the steel pipe 1, in order to place the steel pipe 2 at a minimum distance from the rear surface of the steel support 2 to be erected, the steel pipe 1 is placed at an elevation angle T of about 5 degrees in front of the face. The steel support 2 is provided with a section widening section S of about 6 m which is equal to the length of the guide cell of the drill jumbo in order to secure a driving angle, and the steel support 2 which has already been built in the vicinity of the face F is provided. The feature of this method is that the steel pipes 1 are sequentially driven over the entire length at predetermined intervals with the lower end as a ruler.

In the AGF method, a resin pipe (vinyl chloride pipe) is used as the last pipe of the steel pipe, and the AGF-P method is used in which the pipe is kept in the ground. FIG.
It is a schematic construction situation figure of a tunnel tip receiving work by AGF-P method. Also in the AGF-P method, the steel pipe 1 is driven by a drill jumbo or the like not shown in the figure so as to be pushed from the inside of the steel support 2 already built in the vicinity of the tunnel face F. The steel pipe 1 is disposed in front of the face on the back of a steel support 2 to be erected, and the last pipe of the steel pipe 1 is a resin pipe (vinyl chloride pipe) 1a. Is a position that hinders the installation of the steel shoring 2 during the tunnel excavation, for example, three sets in front of the face (the shoring 2
a, 2b, and 3c). Temporarily buried in the ground with the assumption that it will be removed when the shoring is built, and cast it with an elevation angle T of about 10 degrees. It is better to use a steel pipe 1 over the entire length except for the pipe at the rear end, except that the tunnel section is not provided with a widened section and the lower end of the steel support 2 near the face F is set as a ruler. This is a feature of this method.

[0007]

In the above-mentioned injection type long precedent method (AGF method), the steel pipe is arranged with a minimum separation from the back face of the steel support in front of the tunnel face by a drill jumbo or the like. At an elevation angle of about 5 degrees, it is necessary to provide a section widening section of about 6 m equivalent to the length of the guide cell of the drill jumbo, in order to secure a minimum installation angle. Excessive excavation increases, and the material such as concrete for the widening of the tunnel section and the amount of work for tunnel excavation increase. That is, there is considerable waste in excavating a space larger than the cross section originally required for service, and supporting and lining the space.

[0008] In addition, in the case of the front end of the tunnel by the AGF-P method, the widened section is not provided in the tunnel section, and the pipe at the rearmost end of the steel pipe is formed as a resin pipe (vinyl chloride pipe) on the assumption that it will be removed later. Since the resin pipe at the rearmost end is required to be placed at an elevation angle of about 10 degrees so as to be buried in the ground in the range of about three units in front of the face, the overlapping section (shown in FIG. 8) In the section W), the distance D between the steel support and the steel pipe is increased, and the ground under the steel pipe in this part is loosened depending on the ground conditions, and the resin pipe (vinyl chloride pipe) at the rearmost end is strong. Or the problem arises in the degree of improvement of the ground. In such a case, it is necessary to separately reinforce the support, and the reinforcing material and the amount of work increase.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to widen the cross section of a tunnel in reinforcing a long ground support at the time of excavating a tunnel, underground cavity, or the like. In addition, the present invention provides a ground reinforcement method capable of obtaining a high ground reinforcement effect.

[0010]

According to the present invention, there is provided a ground reinforcement method comprising a drill bit having a base end attached to a rock drill and a drill bit at a tip end capable of being directly or indirectly disengaged from a reinforcing pipe. A hole rod is housed inside a reinforcement pipe, the reinforcement pipe is engaged with the drill bit, and the cutting is performed while sequentially adding the reinforcement pipe and the drill rod in the ground around the cutting face such as tunnel excavation. By drilling with a hole bit, the reinforcing pipe is propelled and set aside while being pulled into the ground, and the solidification material is injected into the surrounding ground through the reinforcing pipe. in steel tube top tube of the reinforcing tube forms an arcuate, multiple after <br/> connection tube straight resin pipe der of the reinforcing tube is, apart of the reinforcing tube and shoring
The plurality of straight resin pipes are connected to the arc-shaped steel pipe so that
And is driven into an arcuately curved state .

Further, in the above-mentioned ground reinforcement method, as the resin pipe used for the subsequent pipe, a fiber reinforced resin pipe made of a resin and a reinforcing fiber may be used. As the resin, for example, unsaturated polyester, epoxy, Vinyl ester or the like can be used, and as the reinforcing fiber, for example, glass fiber, carbon fiber, aramid fiber, or the like can be used.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a construction method of a ground reinforcement method according to the present invention.

FIG. 1 is a longitudinal cross-sectional view schematically showing a state in which a front half of a tunnel is reinforced by a pre-reinforcement method as an embodiment of a ground reinforcement method according to the present invention. As shown in FIG. 1, a rock drill (drill jumbo) 10 is arranged near the face above the tunnel, and the tip of the guide shell 10a of the rock drill 10 has already been tunnel-excavated and the face mirror portion 1
5 is set at the lower end of the steel shoring 12a built in the immediate vicinity.

The excavated wall surface between the face mirror 15 in the longitudinal direction of the tunnel and the steel support (H-200 × 200) 12a in the immediate vicinity is covered with primary shotcrete (thickness t = 50 mm) 13 and furthermore. On the rear side, a secondary shotcrete (thickness t = 200 mm) 14 is applied with a predetermined coating thickness between the steel supports 12 already built at a pitch of 1 m. The face mirror 15 is sprayed with concrete (thickness t = 1)
00 mm), and a pre-drilled hole having a diameter of about 120 mm and a depth of about 300 mm is previously formed in the ground at a predetermined position near the lower end of the steel support 12a at a position along the outer periphery of the face. (Not shown).

The pre-drilled hole may leak the solidified material when the solidified material is injected into the ground around the pipe through the reinforcing pipe 11 to be cast as described later. It is a hole for making and sealing in advance a leak prevention gap larger than the steel pipe at the mouth part around the steel pipe.

A reinforcing pipe 11 to be cast is mounted on the guide shell 10a. The reinforcing pipe 11 includes a leading pipe 11a and a trailing pipe 11b. The leading pipe 11a is an arc-shaped steel pipe, and the trailing pipe 11b is It is a straight resin tube. Top tube 11a
And the length of the subsequent pipe 11b is about 3 to 3.5 m,
The improvement zone is formed by injecting a solidifying material over the entire length of the ground around the reinforcing pipe 11 to be cast, as described later, by using a plurality of the pipes of about 4 to 6 connected in sequence. Therefore, the effect of strengthening the ground as a predecessor can be expected.

Here, the reinforcing pipe 11 will be described in more detail. The leading pipe 11a is an arc-shaped steel pipe as shown in FIG.
The radius of curvature is R = 30 m. At its tip, a stabilizer 1 that prevents rotation of the tube and directs it in a certain direction
1a1 is provided, and a connection portion 11a2 (in the illustrated example, a screw type) such as a screw or a one-touch joint is formed at the rear end. A plurality of strainer holes 11a3, which are discharge ports for the solidified material, are formed at predetermined positions in the periphery.

The succeeding tube 11b as the second and subsequent tubes is shown in FIG.
A straight resin tube as shown in (b), with a screw or one-touch joint connecting portion 11b1 at the front and rear ends.
(The illustrated example is a screw type). At a predetermined position in the periphery, a strainer hole 11b2 serving as a discharge port of the solidified material is provided.
Are provided. The resin tube of this embodiment is made of glass fiber reinforced resin (FRP), and the subsequent tube 11b is made of a resin such as unsaturated polyester, epoxy, vinyl ester, or the like.
A glass fiber, a carbon fiber, a reinforcing fiber such as an aramid fiber or the like is preferable because it can simultaneously achieve the following property and the high strength required in the present invention.

The connection between the subsequent tubes 11b is, for example, as shown in FIG.
As shown in (a), outer diameter 70 mm, inner diameter 60 mm, length 3
The connection portion 11b1 made of glass fiber reinforced resin such as m and having a V-shaped cross-section cutting screw at both ends to minimize cross-section defects
Are connected to each other using a coupler 20 made of aluminum and subjected to V-shaped convex cutting screw processing. It is preferable to apply a resin adhesive at the time of connection to improve the strength of the connection portion. In the connection between the succeeding pipe 11b and the leading pipe 11a, the connecting portion 11b1 of the succeeding pipe 11b and the leading pipe 11
The connection section 11a2 of FIG.
The reinforcing pipe 11 and a drilling rod 19 to be described later are sequentially connected, and are simultaneously driven and drilled over the entire length, so that the high-strength reinforcing pipe 11 can be left over the entire length.

In addition, as shown in FIG.
Drilling bit 19a and ring bit 17 mounted on the tip
In order to drill the ground, a drilling rod 19 for transmitting impact and rotational force is arranged, and a rear end of the drilling rod 19 is connected to the rock drilling machine 10. The drilling rod 19 is a normal AG
It is a slightly bent, straight boring rod slightly smaller than that used in the F method. According to this method, the drilling rod 19 is made to follow the bending pipe 11 while slightly bending it. Therefore, there may be a case where the drilling rod 19 touches the reinforcing pipe 11 in some places. However, even in such a case, the drilling angle is maintained at the tip portion. There is a need to. Therefore, a guide adapter 19b is provided near the tip of the drilling rod 19, and the reinforcing pipe 11 and the drilling rod 1 are provided.
9 are made to coincide with each other in the axial direction. Further, the drilling rod 19 has substantially the same length as the reinforcing pipe 11, and when the reinforcing pipe 11 is added, the drilling rod 19 is also added via the sleeve.

FIG. 5 shows an overall view of the reinforcing pipe 11 and the drilling device. A ring bit 17 having a drilling function is attached to the distal end of the leading pipe 11a via a casing shroud 18, and a drilling rod 19 having a function of assisting drilling is mounted in the distal end of the leading pipe 11. The drill bit 19a is housed in a state of protruding forward from the inside of the ring bit 17. The drill bit 19a is detachably engaged with the ring bit 17 and the casing shroud 18, and the base end of the drill rod 19 is connected to the shank rod 10b of the rock drill 10 with a shank sleeve 10c. .

Thus, the hitting force and the rotating force from the rock drill 10 during the drilling operation are transmitted to the drill bit 19 a and the ring bit 17 via the drill rod 19, and the feed operation of the rock drill 10 is performed. The drilling rod 19 is a guide shell 10a.
A hole is drilled by sliding upward, and a drilling bit 19a is pulled by the drilling bit 19a through the ring bit 17 and the casing shroud 18 to pull the engaged reinforcing pipe 11 through the drilling. Done. The drilling bit 19a may be configured to directly pull the reinforcing pipe.

When drilling the ground with the drill bit 19a and driving the reinforcing pipe 11, the guide shell 10a is moved from the preceding drilling position of the face mirror 15 to the steel shell at a predetermined position in front of the face. On the support 12, the reinforcing pipe 11 is cast at a predetermined elevation angle through which the reinforcing pipe 11 passes. FIG. 1 shows a state in which four reinforcing pipes 11 have already been sequentially connected and driven into the ground in front of the face where the tip of the guide shell 10a is set.

In the above-mentioned drilling, the power from the rock drill 10 is transmitted by the drilling rod 19, and drilling is performed by the drilling bit 19a and the ring bit 17, and the reinforcing pipes 11a, 11
b will be driven and driven. At this time, ring bit 1
7 is a state in which a hole larger in diameter than the outer diameter of the reinforcing pipe 11 is drilled, so that the reinforcing pipe 11 is smoothly pulled. That is, the leading pipe 11a made of a steel pipe does not rotate, but sequentially enters the drilled hole while being curved in an arc shape, and the succeeding pipe 11b made of a resin pipe follows the leading pipe 11a and sequentially curves in an arc shape. While entering the borehole.

Therefore, the drill bit 19 located at the head of the hole
a towing operation and leading diameter expansion of the ring bit 17
It is possible to perform the casting in a predetermined curved state at a predetermined position in the ground without any problem. In this embodiment, the drilling is performed by the drilling bit 19a and the ring bit 17. However, the drilling bit 19a may be formed into a diameter-enlarging bit that can be enlarged and reduced in diameter.

Therefore, a new mirror unit 1 shown by a broken line in FIG.
When the shoring 12 is erected sequentially in the process of tunneling to the 5 'position, the distance from the shoring is smaller in the home mountain reinforcement method than in the case where the shoring 12 is laid straight at the same setting angle ( (About 50cm), high ground reinforcement effect can be obtained at the place to be excavated, and furthermore, it is possible to build the support with minimum separation without widening the tunnel section, and stable tunnel excavation It is possible. In addition, the cast-in succeeding pipe 11b is made of fiber reinforced resin, so that a portion that hinders the installation of the support can be excavated in the excavation process while easily scraping the portion in order, thereby improving work efficiency.

After the completion of the installation of the reinforcing pipe 11, the drill bit 19a is reversed so that the ring bit 17 is rotated.
Then, the engagement state with the casing shell 18 is released, the drilling rod 19 is detached therefrom, and the drilling rod 19 including the drilling bit 19a is withdrawn from the reinforcing pipe 11 and collected. The space in the reinforcing pipe 11 after the removal of the drilling rod 19 is used as a flow path for injecting the solidified material.

Next, an operation of injecting the solidified material into the surrounding ground through the reinforcing pipe 11 is performed. In the present embodiment, as an example of the injection method at the tunnel face position, a valve injection method of a post injection method is employed.

FIG. 6 shows an example of the valve injection method. First, the end pipe 1 of the reinforcing pipe 11 disposed over the entire length.
Leakage of the solidified material is prevented by sealing the gap (mouth) between the rear end of 1b and the preceding hole with a waste 21 or the like soaked with a urethane chemical.

Then, the reinforcing pipe 1 existing over the entire length
The solidification material is injected using the injection tube 1 as an injection tube. For this purpose, strainer holes 11a3 and 11b2 are formed in the reinforcing pipe 11 at predetermined intervals as shown in FIG. 5B. An injection valve 22 is attached to the rear end of the end pipe of the reinforcing pipe 11,
The solidification material is introduced into the reinforcing pipe 11 from the injection hose 24 connected to the injection device 23 via the injection valve 22. The solidified material introduced into the reinforcing pipe 11 is sequentially discharged from the strainer holes 11a3 and 11b2 of the reinforcing pipe 11, is injected into the ground, and solidifies, whereby the reinforcing pipe 11 and the surrounding ground are integrated. It will be reinforced.

[0031]

As described above, the ground reinforcement method of the present invention can bend and bend, and the separation is small as compared with the case where it is driven straight at the same driving angle. It is not necessary to carry out the drilling, and a high ground reinforcement effect can be obtained at the place to be excavated.

Further, the reinforcing pipe in the ground reinforcement method of the present invention is a steel pipe having a special shape in which only the leading pipe is bent.
Subsequent pipes can be installed by following the reinforcement pipe installation shape using the flexibility of the resin. It has the effect of being expensive and reducing costs.

[Brief description of the drawings]

FIG. 1 is a schematic construction diagram showing an embodiment of a ground reinforcement method according to the present invention.

FIG. 2 is a front view of a leading tube.

FIG. 3A is a front view showing a connection example of a subsequent pipe. (B) Front view showing an example of the subsequent pipe.

FIG. 4 is a cross-sectional view of a reinforcing pipe in a state in which a drilling rod is accommodated.

FIG. 5 is an overall view showing an example of a reinforcing pipe and a drilling device.

FIG. 6 is a cross-sectional view showing a valve injection method.

FIG. 7 is a construction diagram showing an example of a conventional steel pipe front receiving method by the AGF method.

FIG. 8 is a schematic construction diagram showing an example of a conventional steel pipe front receiving method by the AGF-P method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rock drill 11a Lead pipe 11b Subsequent pipe 12 Steel support 15 Face mirror part 19 Drill rod 19a Drill bit

────────────────────────────────────────────────── ─── Continued on the front page (72) Yoshio Mitarai, Inventor 2-1 Tsukudocho, Shinjuku-ku, Tokyo, Japan Kumagaya Gumi Co., Ltd. (72) Inventor Tsutomu Matsuo 2-1 Tsukudocho, Shinjuku-ku, Tokyo, Japan Kumagaya Gumi ( 72) Inventor Hideki Takeuchi 1534-1, Nishi-Nasuno-cho, Nasu-gun, Tochigi Pref., Goyo Construction Co., Ltd. (72) Inventor Watanabe Nobuhiro Watanabe, 1553-1, Nishi-Nasuno-cho, Tochigi Pref. (72) Inventor Norihiro Endo 3-2-1 Nishi-Shimbashi, Minato-ku, Tokyo Toho Metal Co., Ltd. (72) Inventor Toru Hama 2-5-10 Shiba, Minato-ku, Tokyo -F.C. (56) References JP-A-8-121073 (JP, A) JP 2-42999 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) E21D 9/04

Claims (2)

(57) [Claims] A drill rod having a drill bit whose base end is attached to a rock drill and has a drill bit at its distal end which is directly or indirectly detachable from a reinforcing pipe is housed inside the reinforcing pipe. The reinforcing pipe is engaged with the drilling bit, and the reinforcing pipe and the drilling rod are sequentially drilled in the ground around the face such as a tunnel excavation while the reinforcing pipe and the drilling rod are sequentially added. In a ground reinforcement method in which a pipe is propelled and driven while being pulled into a ground, and a solidified material is injected into the surrounding ground through the reinforcement pipe, a steel pipe in which a leading pipe of the reinforcement pipe is formed in an arc shape. more subsequent tubes straight resin pipe der reinforcing tube is, the reinforcing tube and支保
A plurality of the straight resin pipes
Natural ground reinforcing construction method, wherein the this <br/> for pouring the state of being arcuately curved to follow the arc-shaped steel tube. 2. The method according to claim 1, wherein the subsequent pipe is made of a resin and a reinforcing fiber.