JP2001200530A - Natural ground consolidating method and tunnel excavating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection method which can continuously perform injection work, and can uniformly carry out natural ground consolidation in a short period of time. SOLUTION: An injection pipe 4 is produced by attaching a cap 6 to one end thereof, forming injection holes 5B, 5B' in the pipe in a longitudinal direction, and forming bag bodies 7 on the pipe so as to cover the injection holes 5B. Then, an external pipe 3 having an injection hole 5A formed therein is produced. Further, the external pipe 3 is inserted into a long hole bored in the natural ground 1, and then the injection pipe 4 is inserted into the external pipe 3. Grout is squeeze-pumped into the injection pipe 4, to thereby improve the natural ground 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention aims to prevent collapse during tunnel excavation by solidifying and stabilizing the ground by using an injection material, and to block water leakage and spring water from the ground. Concerning the method of solidifying the ground.

[0002]

2. Description of the Related Art In tunnel construction in an area where ground conditions such as terrain and geology are unstable, the stability of a face is difficult if a normal support pattern such as shotcrete, rock bolt and steel support cannot be used. In order to ensure the safety of tunnels and tunnels, and to preserve the surrounding environment, efforts are being made to improve the ground conditions.

[0003] The tunnel pre-loading method is carried out for safer and smoother construction when a danger of collapse or the like is expected due to loosening of the ground at the time of excavation of the tunnel.

[0004] In order to prevent the collapse of the ground at the top end of the tunnel, a number of self-drilling bolts are driven into the upper part of the excavated cross section, or hollow bolts are inserted after drilling, and then the surrounding area of the bolt is received. In order to strengthen the ground and secure the adhesion between the bolt and the ground, an injection method of injecting an expansive chemical solution or cement-based injection material into the ground, or a long steel pipe along the top of the tunnel excavation section And an injection method in which an expandable chemical solution or a cement-based injection material is injected into the ground from inside the steel pipe.

[0005] As an example of the tunnel pre-receiving method, when an injection material is injected from an injection hole of a steel pipe, a plurality of partition walls are formed in the injection pipe by previously injecting the injection material into a bag body using a partition wall forming tube. A method of arranging a discharge pipe of the injection material in each space partitioned by the partition wall and injecting the injection material into each space from the injection hole through the discharge pipe (Japanese Patent Publication No. 7-9).
No. 88).

[0006] As the injection material used in these tunnel precedent construction methods, there are a solution type injection material, a cement type injection material, and a water glass type injection material.

[0007]

However, in these tunnel preceding methods, the injection material frequently leaks from the vicinity of the injection port during the injection, so that a sufficient improvement effect cannot be obtained. Was not perfect because of the complexity of the construction.

In the tunnel receiving method using a long steel pipe according to Japanese Patent Publication No. Hei 7-988, a partition wall forming tube, a bag, and a discharge tube must be installed inside the injection tube before the injection operation is performed. In particular, since the number of dispensing tubes increases as the length of the dispensing tube increases, it takes time and money to manufacture the dispensing tube provided with the partition wall forming tube, the bag, and the discharge tube. Since the tube is arranged in the injection hole of the injection tube, there is a problem that the manufacturing of the injection tube is complicated. In addition, in the injection work, a step of injecting the injection material from the partition wall forming tube and then injecting the injection material into the space partitioned by the partition walls must be sequentially performed, so that a continuous injection operation cannot be performed. was there.

As a result of intensive studies, the inventor of the present invention has solved the problem of complication of the injection work in the tunnel head receiving method using a long steel pipe, and has found a method of solidifying the ground which can provide an excellent effect of improving the solidification. Heading, the present invention has been reached.

[0010]

That is, the present invention provides an injection pipe having a plurality of injection holes, and a plurality of bags arranged so as to cover a part of the injection holes. An injection device having an outer pipe, after being inserted into the ground, is a ground solidification method characterized by injecting an injection material from the injection pipe, having a plurality of injection holes After inserting an injection device having an injection pipe, in which a plurality of bags are arranged so as to cover a part of the injection holes, and an outer tube into the ground, the bag is inserted from the injection pipe. A method of solidifying soil, characterized in that a packer is formed by injecting a fluid into the body to inflate the bag body, and an injection material is injected into the ground and the injection pipe is fixed to the ground. Wherein the injection material is a cement-based injection material. And, prior to the excavation of the tunnel, having an injection pipe, which has a plurality of injection holes, and is arranged so that a plurality of bags cover some of the injection holes, and an outer pipe. A tunnel excavation method characterized by inserting an injection device, which is to be excavated from a ground excavation surface, and injecting an injection material from an injection pipe to consolidate the ground, and then excavating the tunnel. Prior to the excavation of the tunnel, it has an injection pipe having a plurality of injection holes, and a plurality of bags are arranged so as to cover a part of the injection holes, and an outer pipe. After inserting the injection device from the ground excavation surface of the ground, a fluid is injected into the bag from the injection pipe to inflate the bag to form a packer, and the injection material is injected into the ground. It is characterized by solidifying the ground and then excavating the tunnel A panel drilling method, injection material is the tunnel excavation method is a cementitious grout, tunneling method is the tunnel excavation method is a tunnel destination receiving method.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in accordance with the order of the injection method (see FIGS. 1 and 2).

The present invention consolidates and stabilizes the surface to be excavated when excavating a tunnel in the ground (the surface to be excavated also includes the periphery thereof), especially the upper half periphery.
It is a ground consolidation method and a tunnel excavation method aiming to prevent collapse during excavation, spring water, etc. and to perform excavation work safely.

In the present invention, immediately after the start of the injection, the fluid is simultaneously injected into the ground and the bag, and by continuing the injection, the fluid becomes full in the bag and the packer is formed. By forming the packer, a plurality of partition walls are formed in the longitudinal direction of the outer tube, and the amount of the injected material discharged from the injection hole formed in the outer tube becomes uniform.

In the present invention, although the form of injection varies depending on the target ground, the present invention can be applied to any ground composed of soil such as gravel soil, sandy soil, and cohesive soil.

In the present invention, first, a long hole 2 is formed in the ground 1. Particularly, in the tunnel receiving method, when excavating a tunnel, it is necessary to solidify the upper half peripheral portion of the surface to be excavated in an arch shape so that the ground does not collapse during tunnel excavation. Therefore, it is preferable that the long hole 2 is formed in the upper half peripheral portion of the surface to be excavated.

Next, the outer tube 3 is inserted into the long hole 2 thus drilled.

The outer tube 3 has a large number of injection holes 5 in the longitudinal direction.
A is open.

The size of the injection hole 5A is not particularly limited, but a diameter of about 10 mm is preferable.

Although the interval between the injection holes 5A is not particularly limited, it varies depending on the soil quality of the target ground, the injection pressure, and the like.

As the material of the outer tube 3, any material such as resin or metal can be used, but metal is preferable in consideration of inserting the outer tube into the ground by a machine or the like.

Next, the injection tube 4 is inserted into the outer tube 3.

The injection tube 4 has a number of injection holes 5B and 5B 'perpendicular to the longitudinal direction, and a bag 7 is attached so as to cover several places of the injection holes 5B. The injection hole 5B covered with the bag body 7 has an effect as an opening for expanding the bag body by injection of the injection material (hereinafter, the opening may be referred to as an injection hole , 5B, 5B '). the sometimes collectively referred to as the 5 B together).

The injection tube 4 to which the bag 7 is attached
Into the outer tube 3.

As the material of the injection tube 4, any material such as PVC or steel can be used. However, in view of workability of the injection hole 5B, insertability into the long hole 2, and ease of handling such as transportation. And those made of PVC are preferred.

The size and size of the injection tube 4 vary depending on the length of the injection tube 4 and the diameter of the long hole 2.
There is no particular limitation.

As the material of the bag 7, most materials such as cloth, rubber, polyethylene, nylon, and vinyl bags can be used, but when the injection tube 4 is inserted into the long hole 2, the bag is damaged due to scratches or the like. Cloth is preferred in that there is less danger of doing so. Among the cloths, those having a waterproof inner surface made of rubber latex or the like, and those having a vinyl sheet set inside the cloth are preferable from the viewpoint of improving waterproofness.

The size of the bag 7 may be large enough to fill the space between the outer tube 3 and the injection tube 4.

The bag 7 preferably has a donut shape when the bag 7 is inflated, since it is easy to process and easily forms a packer.

The bag 7 is attached to the injection tube 4 and both ends of the bag 7 are tied with a string or fixed with an adhesive or a hose band 8 or the like so that the injection material does not leak from both ends. To do. Among these, the method of fixing both ends with the hose bands 8 is preferable from the viewpoint of easy attachment to the injection tube 4 and improvement in waterproofness. In order to form a donut-shaped packer when the bag 7 is inflated, an annular sheet formed by bonding the ends of a cylindrical sheet with an adhesive or the like is fixed to the injection pipe 4, and the bag 7 is removed. It is good to inflate.

The interval between the bags 7 is not particularly limited, but is preferably 1 m or less, because the ground can be more uniformly improved by reducing the interval between the partitions of the bags 7.

If the interval between the bag bodies 7 is increased, there is a possibility that the ground cannot be uniformly improved when the layers of the ground having different granularity and water permeability are formed in alternate layers.

A bag 7 may be wrapped around the tip of the injection tube 4 or a cap 6 may be attached, but it is preferable to attach the cap 6 because it is easy to insert into the outer tube.

After the injection tube 4 thus manufactured is inserted into the outer tube 3, an injection material is injected and the injection operation is started.

In the case of excavating a tunnel, it is necessary to solidify the injected material in the shape of an arch around the upper half of the surface to be excavated so that the ground does not collapse during excavation of the tunnel. for that reason,
As the injection material, a cement-based injection material is preferable because it has such a high strength that the ground does not collapse during tunnel excavation. As the cement in the cement-based injection material, any of various portland cements, fine powder cements, ultra-fine powder cements and the like can be used. Further, by shortening the setting time of the injected material to the order of minutes, it is possible to prevent the injected material from flowing out of the target range of the ground solidification, so that the target range of the ground solidification can be limited, and Since the injection amount of the injection material can be reduced by not injecting the injection material out of the consolidation target range, a cement-based rapid-hardening material may be used in combination with the cement-based injection material in terms of improving work efficiency.

As the cement-based injection material to be used, strength is developed so as to ensure that the ground does not collapse and to improve the resistance to the ground stress and to improve the filling property of the outer pipe. A highly infusible material is required. for that reason,
The cement-based injection material preferably has a water-cement ratio (W / C) of 50 to 600%, more preferably 50 to 200%, from the viewpoint of high initial strength development. However, when a cement-based rapid-hardening material is used in combination with the cement-based quick-injecting material, the W / C cement includes the solid content of the cement-based quick-hardening material.

[0036] For short grout curing time it may be used by increasing the diameter of the injection hole 5 B opened in the injection tube 4. A two-pack injection material can be used by arranging two injection tubes 4 in parallel.

The injection pressure condition of the injection material varies depending on the material of the bag 7, but may be any pressure under which the bag 7 can be formed as a packer, and is preferably 0.1 MPa or more.

By injecting the injection material from the injection pipe 4, the injection material enters the ground 1 and the bag 7, and then the bag 7
Is filled and swells like a balloon to form a packer.
And a plurality of spaces are formed in the middle of the injection pipe 4. By continuing the injection, the injection material fills the space between the packers through the many injection holes 5B 'opened in the injection pipe 4, and thereafter the injection material is uniformly injected into the ground 1 through the injection hole 5A of the outer pipe. You. In order for the bag 7 to form a packer first, the bag 7
The diameter of the injection hole 5B covered by the bag 5 may be larger than the diameter of the injection hole 5B ′ for injecting the injection material into the ground 1, and the number of the injection holes 5B covered by the bag 7 May be larger than the injection holes 5B 'for injecting the injection material into the holes.

As another embodiment, first, a non-hardening fluid such as water may be injected to inflate the bag 7, and then an injection material may be injected.

For a brittle ground where the long hole 2 is easily broken,
The hole may be cut using a casing pipe while protecting the hole wall, and then the casing pipe may be used as an outer pipe. It is preferable to use a casing pipe as an outer pipe at the time of drilling, because the work is easier to insert the outer pipe into the ground.

The injection device of the present invention has an injection hole 5A,
The injection hole 5 B, may be fitted with a rubber sleeve. However, it is preferable not to attach a rubber sleeve in terms of easy production of the injection device and good injection properties.

[0042]

An embodiment will be described below with reference to FIG.

(Preparation of outer tube 3) Length 12.5 m, outer diameter 1
A 14 mm, 3.5 mm thick carbon steel pipe for general structural use is filled with a 10 mm diameter injection hole 5 at regular intervals of 0.6 m in the longitudinal direction.
A was made by forming four crosses (the injection hole 5A on the opposite side of the pipe is not shown) on the outer peripheral surface of the steel pipe.

(Preparation of injection tube 4) Length 12m, diameter 25
cap 7 on one end of an injection pipe 4 made of
Was attached. A φ2 mm injection hole 5B (opening) is formed at regular intervals of 0.6 mm in the longitudinal direction of the PVC pipe,
Four pieces (injection holes 5B on the opposite side of the pipe are not shown) were opened in a cross shape on the outer peripheral surface of the PVC pipe. In addition, an injection hole 5B ′ having a diameter of 2 mm is provided at an intermediate portion of the injection hole 5B (opening).
(Injection hole 5B 'on the opposite side of the pipe)
Is not shown). And, so as to cover the injection hole 5B,
Nineteen cylindrical-shaped cloths waterproofed by applying rubber latex were attached, and both ends were firmly fixed with hose bands 8 to form a bag body 7 (only five bag bodies 7 are illustrated in FIG. 1). Thus, the injection tube 4 was produced.

(Example 1) A hole 1 having a diameter of about 140 mm and a length of 12.5 m was bored in the ground 1 using a boring machine, and an outer pipe 3 was inserted. The outer tube 3 was used as a casing pipe, and the ground was drilled while using the outer tube 3 and a drill bit, and the outer tube 3 was inserted. Next, the injection tube 4 was inserted into the outer tube 3 and set so that the bag 7 of the injection tube 4 was arranged in the middle of the injection hole 5A of the outer tube 3. In addition,
The gap between the outer tube 3 and the ground 1 was sealed with a urethane sealing material (not shown) at a position 1.5 m from the injection port. Thereafter, the injection material was pressure-fed to the injection pipe 4 to perform injection. As the injection material, a mixture of a cement-based injection material composed of ultrafine powder cement and a dispersant and a cement-based rapid hardening material was used. The concentration of the injection material is W / C = 16
It was adjusted to be 6%. The injection conditions were as follows: a discharge rate of 30 L / min and a discharge pressure of 0.5 MPa, and 600 L of the injection material was injected into the injection pipe 4. Immediately before the end of the injection, the injection material (ultra-fine powder cement 100
Parts by mass and 1 part by mass of dispersant, water-cement ratio of 100
%) And the interior of the injection tube 4 and the outer tube 3 are filled,
The injection operation was completed. During the injection, no leakage of the injected material from the vicinity of the injection port of the outer pipe 3 or the injection pipe 4 to the ground surface occurred.
It was clear that the bag functioned as a packer.
After the injection, the surroundings of the outer pipe 3 were excavated to observe the improvement of the ground. As a result, a solid compact was formed around the injection hole 5A of the outer pipe 3 regardless of the depth and position of the injection hole 5A. I was Obviously, it was confirmed that the injection material was uniformly discharged from all the injection holes. Furthermore, as a result of cutting the outer tube 3 and examining the filling property in the tube, it can be determined that the injected material was firmly filled, and that the outer tube had improved resistance to the ground stress, and at the same time, the ground was firmly Could be improved.

(Example 2) The same procedure as in Example 1 was carried out except that water was pressure-fed to the injection pipe 4 to inflate the bag 7 to form a packer, and then the injection material was pressure-fed and injected.
As a result, as in Example 1, no leakage of the injected material from the vicinity of the injection port to the ground surface occurred at all, and the results of the excavation observation showed that the outer pipe 3
A solid compact was formed around the injection hole 5A regardless of the depth or position.

(Example 3) Prior to excavation of a tunnel, a plurality of long holes 2 having a diameter of about 140 mm and a length of 12 m were drilled in the upper half peripheral portion of the ground excavation surface of the ground 1 using a boring machine. . The injection pipes 3 were inserted one by one into the plurality of long holes 2, and the injection material was fed under pressure to perform injection. As the injection material, a mixture of the cement injection material used in Example 1 and the cement-based rapid hardening material was used.
The injection conditions were as follows: discharge rate 30 liter / min, discharge pressure 1.0
The pressure was set to MPa, and 600 liters of the injection material was injected into the injection tube 3 per injection tube. One hour after the injection, a tunnel excavation surface was excavated. As a result, the tunnel did not collapse, there was no spring water, and the excavation work was easy.

(Comparative Example 1) The outer tube 3 was used without using the injection tube 4.
Example 1 was carried out in the same manner as in Example 1 except that the injection material was pressure-fed to the outer tube 3 to perform injection. During the injection, a large amount of leakage of the injection material from the vicinity of the injection port of the outer pipe 3 to the ground surface occurred. After the injection, the lower part of the injection pipe 3 was excavated and the improvement of the ground 1 was observed. As a result, a solidified body was formed around the injection port of the outer pipe 3, but as the depth progressed, the solidified body was formed. Was not solidified at all. Further, since a large amount of leakage of the injection material occurred, the injection material was hardly pressed into the ground 1.

[0049]

By using the injection device of the present invention,
It has the following effects. 1) Since the pouring operation can be performed continuously, uniform ground consolidation can be performed in a short time. 2) Solid formation such as formation of impermeable layer and stabilization excavation is possible. 3) Since the injection device has a simple configuration, it is easy to manufacture the injection device. 4) By forming the packer after inserting the injection tube into the outer tube, the injection tube can be easily inserted into the outer tube without causing friction between the outer tube and the packer. 5) To avoid having to pull out the injection tube at the end of injection,
The work of filling the injection hole after the drawing is not required, and the work is easy. 6) The effect of improving permeation in the sand layer can be expected. 7) The ground can be uniformly consolidated even if the ground has different layers of different grain size and permeability. 8) Safe excavation by preventing loosening of the ground and deformation of the ground surface due to tunnel excavation

[Brief description of the drawings]

FIG. 1 is a partial sectional view of an injection device inserted into a long hole to form a packer.

FIG. 2 is a cross-sectional view taken along line AA ′ and line BB ′ of the injection device of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ground 2 Long hole 3 Outer pipe 4 Injection pipe 5A, 5B 'injection hole 5B Injection hole (opening) 6 Cap 7 Bag body 8 Hose band

Claims (7)

[Claims] 1. An injection device having a plurality of injection holes, an injection tube having a plurality of bags arranged so as to cover a part of the injection holes, and an outer tube. After being inserted into the ground, an injection material is injected from an injection pipe. 2. An injection device having a plurality of injection holes, an injection tube having a plurality of bags disposed so as to cover a part of the injection holes, and an outer tube. Is inserted into the ground, then a fluid is injected into the bag from the injection pipe to inflate the bag to form the packer, and the injection material is injected into the ground to fix the injection pipe to the ground. The soil compaction method characterized by the following. 3. The method according to claim 1, wherein the injection material is a cement-based injection material. 4. An injection pipe having a plurality of injection holes and having a plurality of bags disposed so as to cover a part of the injection holes, and an outer pipe, prior to excavation of the tunnel. A tunnel excavation characterized by inserting an injection device to be provided from a ground excavation surface of a ground, then injecting an injection material from an injection pipe to solidify the ground, and then excavating the tunnel. Construction method. 5. An injection pipe having a plurality of injection holes and a plurality of bags arranged so as to cover a part of the injection holes, and an outer pipe, prior to excavation of the tunnel. After inserting the injection device provided from the ground excavation surface of the ground, a fluid is injected into the bag from the injection pipe to inflate the bag to form a packer, and the injection material is injected into the ground. A tunnel excavation method characterized by excavating a tunnel by injecting it into a ground. 6. The tunnel excavation method according to claim 4, wherein the injection material is a cement-based injection material. 7. The tunnel excavation method according to claim 4, wherein the tunnel excavation method is a tunnel precedent method.