JP3515046B2 - 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 natural ground reinforcement method suitable mainly for use as a front receiving work for reinforcing the ground in front of a face when constructing a tunnel.

[0002]

2. Description of the Related Art Conventionally, when excavating a tunnel in rocks or the like having poor geological conditions, the tunnel has been reinforced while reinforcing the rock. Then, as a natural ground reinforcement method to be performed when excavating a tunnel while reinforcing the preceding natural rock, an arch-shaped ground improvement material, which is an arch-shaped ground improvement body, is formed from the face to the outer periphery of the tunnel before excavation. There is a long tip receiving method to reinforce the ground, and this long tip receiving method can be easily installed using standard drilling machine equipment such as hydraulic drill jumbo used for mountain tunnel method, injection using steel pipe There is a method of receiving the ceremony first.

And as the injection type receiving method,
For example, a diameter-expanding bit attached to the tip of a hole-drilling rod or a ring bit provided at the tip of a steel pipe is used for drilling, and a double-pipe system is used to sequentially add perforated steel pipes with a diameter of about 100 mm and set them at a predetermined elevation angle. , There is a method of reinforcing the ground by injecting a solidifying material such as a chemical solution into the surrounding ground through the discharge holes of the steel pipe peripheral wall. The construction method can be used for a wide variety of natural conditions and can receive long lengths, so it is used extensively for the purpose of suppressing advance displacement of the natural rock, preventing loosening of the natural rock, ensuring safety of construction, etc. There is.

FIG. 9 shows a state in which the above-mentioned injection type receiving method is applied to the ground, and a steel pipe 23 is driven from the face 22a into the ground 22 in the tunnel space 21 and then driven. A solidified region 24 is formed around the steel pipe 23. In this method, the steel pipe 23 and the steel pipe 23
The steel pipe 23 and the rock hole wall are closely contacted with each other by filling the gap 25 with the hole wall of the rock mass 22 in which the steel pipe 23 is placed.
By injecting the injected chemical solution into the ground 22 around the ground, and increasing the binding force between rock fragments or soil particles to form the consolidation region 24, an arch-shaped ground improvement body is formed in the ground in front of the cutting face. ing.

When the steel pipe 23 is driven in the above-mentioned construction method, a pilot hole having a diameter slightly larger than that of the steel pipe 23 is formed on the outer circumference of the face.
Drilling is performed about 0 mm in advance, and the steel pipe 23 is added from the prepared hole and is laid for a predetermined length. After that, a caulking material is filled in the pilot hole, and a urethane-based or, in some cases, a cement-based chemical liquid is injected into the steel pipe 23 to form a consolidation region 24 around the steel pipe 23.

As an example of injecting a chemical solution, for example, FIG.
There is a chemical liquid injection method shown in (a), and in this example, an insert pipe 23a is provided inside a steel pipe 23,
Three drug solution injecting hoses 23b are inserted in a, a static mixer 23c is provided at the tip of each drug solution injecting hose 23b, and the tip of each drug solution injecting hose 23b is located at a predetermined distance in the insert pipe 23a. It is arranged in each. Further, a mouth caulking 27a is provided between the mirror sprayed concrete 26 and the end of the steel pipe 23, and an in-pipe caulking 27b is provided between the end of the steel pipe 23 and the chemical solution injection hose 23b. And the chemical liquid injection hose 2
The chemical liquid is injected from 3b to insert pipe 23a and steel pipe 2
The chemical liquid penetrates into the surrounding ground 22 from No. 3.

Another example of injecting a chemical solution is shown in FIG. 10 (b). In this example, an insert packer 23d and a cloth cylinder packer 23e are provided in a steel pipe 23 in which a slit 230 is formed. 23e is arranged at the position where the slit 230 is formed. A chemical liquid injection hose 23b is inserted into the insert packer 23d, and a separate chemical liquid injection hose 23f is guided into the cloth cylinder packer 23e. Mirror-finished concrete 2
No. 6 and the end of the steel pipe 23 are provided with a mouth caulk 27 a, and a check valve 28 is attached to the end of the steel pipe 23.
In this example, first, a chemical solution is injected into the cloth tube packer 23e to form a bulkhead with the solidifying material leaked from the slit 230, and then a solidification area is formed with the chemical solution injected through the insert packer 23d and the steel pipe 23. To do.

[0008]

However, in such a ground receiving method, the steel pipe 23 is made of steel in the tunnel face 22a provided with the mirror-sprayed concrete 26, as shown in FIG. 11 (a), for example. In order to arrange the steel pipe 23 from the inside of the support 29a to the back of the steel support 29b in front of the face to be built later with a minimum distance, an elevation angle of about 4 to 5 degrees is set from the tunnel space 21. Put it on 2
Place within 2 In order to maintain this casting angle T, it is necessary to provide a cross-section widening section S of about 6 m, which corresponds to the guide cell length of the drill jumbo, but in this case, the secondary lining concrete placing space 30 increases. As a result, extra material such as concrete for the tunnel cross-section widening is required, and the amount of work such as tunnel excavation also increases.

Although there is also a ground tip receiving method as shown in FIG. 11 (b) in which the section widening section S is not provided in the tunnel space 21, such a method allows the pipe at the rearmost end of the steel pipe 23 to be cut later. A resin pipe 31 such as a vinyl chloride pipe,
The resin pipe 31 at the rearmost end is buried in the ground 22 within the range of about three steel supports 29 built in front of the face, and is driven with an elevation angle of about 10 degrees. Steel support 29 in the lap section and steel pipe 23 already cast
The distance D from the resin pipe is large, and the ground 22 under the steel pipe 23 is loosened depending on the ground condition, and the resin pipe 31 lacking in rigidity at the rearmost end.
Anxiety about the strength of.

Further, as another construction method in which the cross-section widening section S is not provided, there is a front receiving construction method in which the entire length of the reinforcing pipe is made of fiber reinforced resin, but the construction method may be very expensive in some cases, A special excavation method must be used so that the pipe is not deformed during driving, and the structure of the excavation rod or the excavation bit or the excavation method is limited.

The present invention has been made in view of the above problems, and it is possible to improve and reinforce a suitable ground without needing to provide a cross-section widening section, and to use various excavation methods. It is an object of the present invention to provide a ground reinforcement method that can be implemented at low cost.

[0012]

In the ground reinforcement method of the present invention, a plurality of pipes each having a discharge hole formed in a peripheral wall are sequentially connected to each other by driving them into the ground at a predetermined elevation angle and connecting them. Forming a solidified region through the reinforcing pipe by injecting a solidifying material through the reinforcing pipe to form a solidified region in the natural ground around the reinforcing pipe. The portion of the reinforcing pipe located at the base of the reinforcement pipe is formed by connecting a plurality of short pipes through an easily separable joint means, and the portion exposed from the natural ground by the joined short pipes as the natural ground is dug. Is sequentially separated from the reinforcing pipe.

As described above, the portion located at the mouth of the reinforcing pipe is configured to be easily broken, and the portion is removed in accordance with the excavation work, so that it is not necessary to provide a cross-section widening section, and workability can be improved. In addition, it is possible to perform appropriate ground improvement and ground reinforcement.

Furthermore, the present invention is characterized in that, in the above-mentioned ground reinforcement method, the short pipe or the mouth pipe is a porous pipe. By forming the portion located at the mouth part as a perforated pipe, the solidifying material is preliminarily permeated into the surrounding ground around the mouth part of the reinforcing pipe to form the bulkhead region, and the solidifying material leaks in the bulkhead region. While preventing or suppressing, it becomes possible to infiltrate the surrounding material of the reinforcing pipe with the solidifying material to form an appropriate solidified region, and it is possible to improve the natural ground and reinforce the natural ground.

Further, according to the present invention, in the above-mentioned ground reinforcement method, the ground to be reinforced is a tunnel ground, and a plurality of the reinforcing pipes to be cast toward the front ground have an arch shape on the outer circumference of the face. Is characterized by. By arranging the reinforcing pipe in an arch shape and providing the front receiving work, it is possible to appropriately perform the ground reinforcement required for tunnel construction.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The ground reinforcement method of the present invention will be described below with reference to specific embodiments shown in the drawings. 1 to 3 show an outline of a construction state in the ground reinforcement method of the present invention, FIG. 4 shows a reinforcing pipe used in the present invention, and FIGS.
[Fig. 3] is a vertical cross-sectional view in accordance with the construction procedure of the ground reinforcement method of the present invention.

As shown in FIGS. 1 to 3, in the tunnel being constructed by using the present invention, the concrete face 1a of the natural ground 1 is sprayed with concrete 2 and the tunnel is already excavated behind the face 1a. Sprayed concrete (not shown) is applied to the space 3 so as to cover the side wall and the rock surface of the arch part, and the steel supporter 4 is formed on the inner side of the space 3 along the cross-sectional shape of the tunnel. , In the direction of tunnel excavation, for example, 1
It is built in every predetermined interval such as every m.

In the upper part of the periphery of the tunnel space 3, pre-receivers 5 which are constructed prior to the excavation work are provided at predetermined intervals in the excavation direction, are formed in an arch shape and are arranged in the natural ground 1. There is. The front receiving work 5 includes a reinforcing pipe 6 which is a natural reinforcing material which is placed along the cross-sectional shape of the tunnel at a predetermined pitch and at a predetermined interval in the direction of excavation, and a solidification injected through the reinforcing pipe 6. Ground 1 and consolidation area 7 consolidated by wood
The reinforcing pipe 6 is composed of a plurality of steel pipes connected by a coupler 61 as described later. Further, a front receiving work 5 under construction is provided in an arch shape from the outer circumference of the face 1a toward the ground 1 in front.

As shown in FIG. 3, the front receiving work 5 is provided with a mouth portion 5a corresponding to the length L to be cut later. Then, in the reinforcing pipe 6 that constitutes the front receiving work 5, the diameter 100 mm on the hole back side 5b from the mouth portion 5a,
In the present embodiment, four long pipes 62 made of steel having a length of 3 m are connected by a screw type coupler 61 as a predetermined number, whereas the mouth portion 5a has a diameter of 100 mm and a predetermined unit length of 1 m of steel. In the present embodiment, three short pipes 63 made of a predetermined number are connected via an easily destructible coupler 61a which is a joint means. The joint means may be a screw-type coupler 61 or a coupler or the like made by welding or the like for connection.

As shown in FIG. 4, each of the long pipes 62 and each of the short pipes 63 has a large number of small holes 62a, 6 in the peripheral wall over the entire length.
3a is drilled. As an example of the structure of the reinforcing pipe 6, FIG.
In the first example of (a), the long pipe 62 and the short pipe 62 on the inner side 5b of the hole.
Are connected by a coupler 61a, and the short pipes 62, 62 are connected by a coupler 61a at the mouth portion 5a. In this example, the coupler 61a is vinyl chloride (V
P), or a tubular sleeve made of a material that can be bent and cut while having the required strength such as GFRP, aluminum, and zinc-plated steel, to which short pipes 62, 62 are mutually screwed in this example. It is designed to connect. Long pipe 6
The easily destructible coupler 61a connecting the 2 and the short pipe 63 can be the normal coupler 61, and this is the same in the embodiments described later.

Further, in the second example of FIG. 4 (b), the mouth portion 5a
As the short tube 63, a perforated tube having a large number of small holes 63a made of expanded metal or the like having a predetermined length is used, and the perforated tube is screwed and connected to a coupler 61a which is a tubular sleeve such as vinyl chloride. Other configurations are the same as those in the first example. The long tube 62 and the mouth tube 64 on the hole back side 5b can be replaced with the coupler 61a as a normal coupler 61.

In the above description, the short pipe 63 provided at the mouth portion 5a is made of a rigid material made of steel, and is strong against the axial force, but the force for joining the short pipe 63 every 1 m is weak. Therefore, when a lateral force is generated, each short tube 63
Are easily separated from other portions of the reinforcing pipe 6. The material of the pipe forming the reinforcing pipe 6 is made of steel in this embodiment, but any appropriate material can be used as long as it has the required strength.

Then, in the front receiving work 5, as shown in FIG. 1 to FIG.
By the solidifying material that has penetrated into, the solidifying region 7 is formed in the ground 1 around the reinforcing pipe 6. As the solidifying material in the present embodiment, urethane-based chemicals such as urethane, silica resin, and inorganic composite urethane, which have a relatively short curing time, are used, but it is also possible to use cement-based chemicals as the solidifying material. .

In FIGS. 1 to 3, 8 is a drill jumbo, 1b is an area to be excavated, and L is a length cut along with the short pipe 63 as the mouth portion 5a.

Next, the procedure for constructing the front receiving work 5 will be described with reference to FIGS. The sprayed concrete 2 and the like are omitted in FIGS.

When constructing the pre-bearing work 5, first, as shown in FIG. 5, the diameter of the steel support work 4 built immediately before the face 1a is measured from a predetermined position at the lower end of the steel support work 4 toward the ground 1 in front. 1
A long hole 62 made of steel that forms a reinforcing pipe 6 in a guide cell 8a of a drill jumbo (rock drilling machine) 8 arranged in the tunnel space 3 while drilling a pilot hole 9 having a depth of about 60 mm and a depth of 300 mm. (See Fig. 1). A drilling rod 11 having a diameter-expanding bit 10 mounted at the tip is inserted into the long pipe 62, and the rear end of the drilling rod 11 is connected to the shank of the drill jumbo 8 and expanded through the drilling rod 11. Diameter bit 1
The impact force and the rotational force are transmitted to 0 to drill a hole.

The drilling method is arbitrary, and in addition to the method of drilling with the diameter-expanding bit 10 attached to the tip of the drilling rod 11 which is passed through the long tube 62 as described above, for example, the reinforcing tube 6 is used. A method in which a ring bit is attached to the tip of the long pipe 62 made of steel, and a striking force or a rotational force is transmitted to the ring bit through the drilling rod 11 passing through the long pipe 62 to drill a hole Good.

At the time of drilling and placing, the guide cell 8a is set to 3
Set to a predetermined elevation angle of about 6 degrees, preferably about 5 degrees, and have a small hole 62a from the lower hole 9 toward the natural ground 1 located in front of the cutting face 1a while drilling with the expanding bit 10 The long pipe 62 is placed. In this embodiment, the basic length is 3
It is assumed that four long pipes 62 each having a length of m are to be installed,
The long pipe 62 is placed while being connected by the screw-in type coupler 61.

At the opening 5a located at the rearmost end of the front receiving work 5, as shown in FIG. 6, a coupler 61a made of vinyl chloride or the like is provided for connecting a short steel tube 63 of 1 m in length. The coupler 6 is screwed into the end of the long pipe 62.
It is placed in a state where the three short tubes 63 are connected via 1a. Thus, the plurality of long pipes 62 and the short pipes 63 are left in the natural ground 1 in front of the face 1a as the reinforcing pipes 6 having a predetermined length.

Since the load applied to the coupler 61a at the mouth portion 5a of about 3 m in the operation of placing the reinforcing pipe 6 is very small, it is made of an easily destructible material such as vinyl chloride. Even so, it will not be broken by the impact of casting. After leaving the entire length of the reinforcing pipe 6 by casting, as shown in FIG. 6, caulking is performed by filling the portion of the pilot hole 9 with a caulking material 12 such as caulking capsule and waste.

In this state, when the chemical solution injecting hose is set in the reinforcing tube 6 and the chemical solution of the solidifying material is injected by the method as shown in FIG. 10A, for example, the long tube 62 and the short tube forming the reinforcing tube 6 The solidifying material is injected into the surrounding ground 1 from the small holes 62a and 63a in the peripheral wall of the pipe 63, and the surrounding ground 1 in front of the cutting face 1a is solidified to form the solidified region 7 as shown in FIG. At that time, the short tube 63 of the mouth portion 5a is made of the same material as the long tube 62 on the inner side 5b of the hole but has the same length, and the small hole 63a is formed in the same manner as the long tube 62. A uniform consolidated region 7 is formed over the entire length of the work 5.

The front receiving work 5 is formed in an arch shape along the outer periphery of the face 1a in the tunnel. By constructing the arch-shaped front receiving work 5 on the outer circumference of the face 1a, the stability of the ground 1 to be excavated located below the front receiving work 5 is secured. Then, the tunnel is further advanced to advance the cutting face 1a, and the excavation work of the tunnel is advanced while the support works 4 are sequentially built up by the amount by which the cutting face 1a is advanced.

When the excavation work is performed, the natural ground 1 on which the mouth portion 5a of the front receiving work 5 placed immediately before is located is also excavated.
As shown in FIG. 3, in the mouth portion 5a of the reinforcing pipe 6 which constitutes the front receiving work 5, the 1 m short pipe 63 provided at the rearmost end is cut and separated from the reinforcing pipe 6. At this time, since the short pipe 63 located at the rearmost end is joined to the short pipe 63 on the inner side of the coupler 61a made of a vinyl chloride pipe or the like, the coupler 61a is easily broken during excavation or The short pipe 63 easily falls off from the coupler 61a. Also, since the short tube 63 with a length of 1 m is detached and separated,
The short pipe 63 can be easily separated during excavation work.

Thereafter, as shown in FIG. 8, the coupler 61a is destroyed or the coupler 6 is destroyed as the tunnel excavation proceeds.
The short pipe 63 is dropped from 1a, and the short pipe 63 is sequentially separated from the reinforcing pipe 6 of the mouth portion 5a by 1 m. Finally, the short pipe 63 or the long pipe 62 connected to the long pipe 62 on the inner side 5b of the hole.
The coupler 61a connecting the short tube 63 and the short tube 63 is cut off and separated from the reinforcing tube 6. That is, as the natural ground 1 is dug and expanded, the steel pipe is sequentially cut off from the reinforcing pipe 6 exposed at the mouth portion 5a.

In the tunnel construction by the above-mentioned ground reinforcement method, it is not necessary to widen the cross section along with the tunnel excavation, and the supporting works 4 can be sequentially built in with the same cross section.
Further, what constitutes the reinforcing pipe 6 located at the mouth portion 5a is a short pipe 63 made of steel having a predetermined rigidity,
Since the long pipe 62 located at b is also a steel pipe having a predetermined rigidity, the axial force as the reinforcing pipe 6 is properly secured, and the surrounding natural ground 1
Infiltration of the solidifying material into the solidification area is reliably achieved, and the appropriate solidifying area 7
As a result, the stability of the ground is sufficiently secured.
Therefore, the tunnel excavation work can be performed efficiently and safely.

When a porous tube as shown in FIG. 4 (b) is used for the short tube 63 of the mouth portion 5a, the mouth portion 5 is filled when the chemical solution is injected.
The chemical liquid is leaked from the a through the small hole 63a of the perforated pipe, and the chemical liquid leaked to the outer peripheral ground 1 of the reinforcing pipe 6 at the mouth portion 5a solidifies the natural ground 1 prior to the chemical liquid injection on the inner side 5b of the hole. It is possible to form the consolidation area 7 after forming the bulkhead area at the mouth portion 5a of the pre-receiving work 5. in this case,
Although it is slightly disadvantageous in terms of rigidity compared to the reinforcing pipe 6 of the example shown in FIG. 4 (a), reliable injection without leakage of the solidifying material can be performed, and as a result, a good ground improvement effect is obtained. Obtainable.

In the embodiment described above, the short pipe 63
A coupler 61a made of vinyl chloride or the like is used as a joint means for easily separating the
1a is a female screw type and is located outside the short pipe 63. However, it is a joint means of connecting a coupler formed with a male screw to the inside of the short pipe 63 formed with a female screw or the long pipe 62. It may be. Further, a plug-in type coupler which does not use screws may be used as joint means in combination with an adhesive.

In the ground reinforcement method of the above-mentioned embodiment, an example in which the present invention is used as a front receiving work of a tunnel has been described, but the application of the present invention reinforces the ground 1 located in front of the face face 1a of the tunnel. It is not limited to the front-end work 5
For example, even when it is used as a temporary support for an excavation space that is planned to be widened by a predetermined width later, the effect can be effectively exhibited.

[0039]

EFFECTS OF THE INVENTION In the ground reinforcement method of the present invention, as described above, the portion of the reinforcing pipe located at the base of the reinforcing pipe is configured to be easily broken, and the portion is sequentially separated from the reinforcing pipe in association with the excavation work. In addition, it is possible to improve the workability without providing a cross-section widening section, and it is possible to make an appropriate ground improvement, and it is possible to provide the required ground reinforcement.

Further, the ground reinforcement method of the present invention can be applied to tunnel excavation by various excavation methods and can be implemented at low cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a tunnel showing a construction state of a ground reinforcement method of the present invention.

FIG. 2 is a cross-sectional view of a tunnel showing a construction state of the ground reinforcement method of the present invention.

FIG. 3 is an enlarged cross-sectional view showing a face portion in a state in which a front receiving work is applied from the face face in FIG.

FIG. 4 (a) is a front view showing the reinforcing pipe of the first embodiment. (B) The front view which shows the reinforcement pipe of 2nd Example.

FIG. 5 is a vertical cross-sectional view showing a state in which a reinforcing pipe is driven by the ground reinforcement method of the present invention.

FIG. 6 is a vertical cross-sectional view showing a formation state of a consolidation region by the ground reinforcement method of the present invention.

FIG. 7 is a vertical cross-sectional view showing a state in which excavation work has been started by the ground reinforcement method of the present invention.

FIG. 8 is a vertical cross-sectional view showing a state in which the excavation work has progressed by the ground reinforcement method of the present invention.

FIG. 9 (a) is a longitudinal sectional view of a tunnel showing a construction state of a conventional ground reinforcement method. (B) A cross-sectional view of a tunnel showing a construction state of a conventional ground reinforcement method. (C) A cross-sectional view showing a steel pipe placed in the ground.

FIG. 10 (a) is a vertical cross-sectional view showing a first example of chemical injection in a conventional ground reinforcement method. (B) A longitudinal cross-sectional view showing a second example of the chemical solution injection in the conventional ground reinforcement method.

FIG. 11 (a) is a vertical cross-sectional view of a tunnel showing a construction state of a conventional ground reinforcement method in which a cross-section widening section is provided. (B) A vertical cross-sectional view of a tunnel showing a construction state of a conventional ground reinforcement method without providing a cross-section widening section.

[Explanation of symbols]

1 ground 1a Face 3 tunnel space 4 Support work 5 Receiving work 5a mouth 5b hole inside 6 Reinforcement pipe 61, 61a coupler 62 long pipe 63 short tube 62a, 63a Small hole 7 consolidation area

Continuation of front page (56) Reference JP-A-8-121073 (JP, A) JP-A-10-37657 (JP, A) JP-A-2000-34882 (JP, A) JP-A-2000-45680 (JP, A) ) JP 2000-265778 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) E21D 9/04

Claims (3)

(57) [Claims] 1. A reinforcing pipe composed of a plurality of connected pipes is formed by sequentially connecting a plurality of pipes having discharge holes formed in a peripheral wall and driving them into the natural ground at a predetermined elevation angle. Then, in the natural ground reinforcement method of injecting the solidifying material through the reinforcing pipe to form the solidified region in the natural ground around the reinforcing pipe, it is easy to separate the portion located at the mouth of the reinforcing pipe. It is characterized in that a plurality of short pipes are connected through a joint means, and as the ground is dug, the exposed portions of the ground by the connected short pipes are sequentially separated from the reinforcing pipe. Ground reinforcement method. 2. The natural ground reinforcement method according to claim 1, wherein the short pipe or the mouth pipe is a perforated pipe. 3. The ground to be reinforced is a tunnel ground, and a plurality of the reinforcing pipes driven toward the front ground are arched on the outer circumference of the face. Ground reinforcement method.