JP2002081052A - Natural ground reinforcing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an economical injection type natural ground reinforcing method providing uniform and sure natural soil improvement effect over the whole length of a region to be reinforced and facilitating the construction in a natural ground reinforcing method applied to, for example, a prelining construction for a tunnel, a reinforcing works for a facing boundary part, or a slope stabilization method. SOLUTION: This consolidation material injection type natural ground reinforcing method using a reinforcing pipe 1 is characterized in that a bulk head B formed of a consolidation material of short gel time is formed in the natural ground in a region corresponding to the prescribed length part of a mouth part relative to the reinforcing pipe whole length, a consolidation material of long gel time is injected in the inner part of the part formed with the bulk head, and the consolidation material of the long gel time is made to infiltrate into the wide range of natural ground, while the bulk head prevents the leakage toward the mouth side.

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 applied to, for example, tunnel preloading, face mirror reinforcement or slope stabilization.

[0002]

2. Description of the Related Art Heretofore, for example, as a subterranean stabilization method at the time of tunnel excavation in a mountain tunnel method, there is known a receiving work and a reinforcing method of a face mirror. FIG. 7 shows an example of a precedent work, in which a reinforcing pipe 1 made of a perforated steel pipe or the like is driven toward the front of the face along the upper edge of the face mirror W at the tip of the tunnel during excavation. . In the figure, W1 indicates a shotcrete sprayed on the face mirror W, and S indicates a secondary lining concrete casting space.

[0003] As a method of placing the reinforcing pipe as described above,
Normally, a so-called double pipe method is adopted, and drilling is performed by means of an expanding bit attached to the tip of a drilling rod or a ring bit provided at the tip of a reinforcing pipe made of a perforated steel pipe having a diameter of about 100 mm. And a reinforcing pipe of a predetermined length is cast.

At this time, the reinforcing pipe 1 is provided from the inside of the steel support F already built in the tunnel space T excavated as shown in FIG. In order to arrange the reinforcing pipe 1 on the (upper surface side) with a minimum distance from the reinforcing pipe 1, the reinforcing pipe 1 is cast with an elevation angle θ of usually about 4 to 5 degrees with respect to the horizontal direction or the tunnel excavation direction.

[0005] As shown in FIG. 8A, a consolidated material G is injected into the ground M in front of the face mirror W through the reinforcing pipe 1 cast as described above. The consolidated material thus filled is filled in the gap between the reinforcing pipe 1 and the inner surface of the drilled hole h in which the reinforcing pipe 1 is cast, as shown in FIG. At the same time, as shown in FIG. 8B, the consolidation material penetrates and solidifies into the ground through a small through-hole (not shown in the figure) around the reinforcing pipe 1 made of a perforated steel pipe or the like. An arch-shaped consolidation region is formed, thereby improving the ground and strengthening the bonding force between rock pieces or soil particles.

[0006] Various types of cementing materials such as cement and resin are generally used as the cementing material used for the above-mentioned tunnel precedent work and mirror part reinforcing work. Is a fast-setting material consisting of a common cement-based cement such as standard cement milk or premix mortar, which is widely used in general, and a special quick-setting cement, or a material combining fine-grain cement and a quick-setting material. And cement-based consolidation materials. For example, urethane-based resins are often used as resin-based consolidation materials.

As a method for filling the consolidated material, for example, as shown in FIG. 9 (a), there is a continuous batch injection method in which a batch injection is continuously performed from the opening (mouth) side of the drilled hole h by the injection pipe P. There is an interval injection method in which a plurality of injection tubes P1 to P3 having different lengths are provided as shown in FIG. In the figure, C1 and C2 denote caulking materials interposed between the reinforcing pipe 1 and the mouth of the hole h, and between the reinforcing pipe and the injection pipe.

The above-mentioned ordinary cement-based consolidation material is economical because of low material cost, and has a good gel permeability (time until hardening), generally 30 minutes or more, so that it has good permeability, Wide range of improvement. In other words, if the gel time is short, it solidifies before permeating a wide area, but if the gel time is long, there is an advantage that it can permeate a wide area. However, on the other hand, since the gel time is long, the consolidated material remains in an uncured state in both continuous batch injection as shown in FIG. 10 (a) and interval injection as shown in FIG. 10 (b). It may escape into the rough ground gap near the face, causing a leak to the open face side, and as a result, there is a possibility that the consolidation material may not spread to the planned improvement area in the deep part of the ground.

On the other hand, the gel time of the quick-setting cement-based cement is relatively short, for example, the gel time of standard cement milk and premix mortar, which are generally widely used, is 30 minutes or more, and the gel time of urethane resin is It is about 30 to 120 seconds. Therefore, for example, in the case of interval injection, the injection is stopped intermittently when a leak occurs, the resin in the ground gap is cured, and injection is performed again while observing the situation. It is known that by adjusting the amount, it is possible to take measures against leaks, but to do this without clogging the pump or nozzle requires a high degree of skill and intuition. In addition, quick-setting cement-based binders and resin-based binders are more expensive than ordinary cement-based binders, and require special pumps and kneading equipment not usually found in tunnel construction sites.

[0010]

DISCLOSURE OF THE INVENTION The present invention has been proposed in view of the above problems, and provides a uniform and reliable ground improvement effect over the entire length of a region to be reinforced, and is economical. Moreover, it is an object of the present invention to provide an injection type ground reinforcement method which is easy to construct.

[0011]

Means for Solving the Problems In order to achieve the above-mentioned object, a ground reinforcement method according to the present invention has the following constitution.

In other words, in the ground reinforcement method of the solidification material injection type using the reinforcing pipe, the solidification material having a short gel time is applied to the ground corresponding to a predetermined length of the mouth portion with respect to the entire length of the reinforcing pipe. Forming a bulkhead, injecting a solidified material having a long gel time into a portion deeper than a portion where the bulkhead is formed, and preventing a leak to the mouth side by the bulkhead, while forming a solidified material having a long gel time. Is permeated into a wide range of ground to reinforce the ground.

As the binder having a short gel time, for example, a fast-setting cement-based binder or a resin-based binder having a gel time of 2 minutes or less may be used. More preferably, a resin-based binder having a gel time of about 1 minute is used. It is preferable to use a binder. As the solidification material having a long gel time, a normal cement-based solidification material having a gel time of 30 minutes or more can be used.
Furthermore, a packer can be provided in the reinforcing pipe corresponding to a predetermined length position of the mouth portion as necessary.

[0014]

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.
FIG. 2 is a cross-sectional view of a schematic configuration of an embodiment in which the ground reinforcement method according to the present invention is applied to pre-piercing during tunnel excavation, and FIG. 2 is an enlarged cross-sectional view of a part thereof.

In this embodiment, the reinforcing pipe 1 has an outer diameter of 100 mm.
mm perforated steel pipe having a large number of small through holes in the peripheral wall
Is set at a predetermined casting angle with respect to the ground, and successively added while drilling by the double pipe method to form a reinforcing pipe 1 of a predetermined length.
Is installed. The driving method can be performed in the same manner as in the related art.

As shown in FIG. 3 (a), the reinforcing pipe 1 is formed by using a perforated steel pipe 11 over its entire length, or as shown in FIG. A metal tube or the like constituted by a porous tube 12 or the like can be used.

As shown in FIG. 2, the feature of the present invention is that a predetermined length of the mouth portion with respect to the entire length of the reinforcing pipe (about 1 m to 5 m).
Is used as a bulkhead region, and a binder having a short gel time such as a resin-based or fast-setting cement-based binder is injected into the ground around the reinforcing pipe in this portion to form the bulkhead B in the ground itself. is there. The bulkhead B is 30 to 12 in the case of a resin-based solidifying material such as urethane resin.
It solidifies in about 0 seconds, and can be formed promptly and limited to a portion with a loose mouth. By injecting, for example, a cement-based consolidation material having a long gel time into the deeper side than the bulkhead B and allowing it to permeate and harden over a wide range to form the consolidation region A, an accurate ground improvement effect can be obtained. Things.

In order to form the bulkhead B, a packer 2 for forming a bulkhead as shown in FIG. 4 may be used as necessary. In the illustrated example, the packer 2
The entire body is formed in a substantially cylindrical shape so that a later-described solidification material injection pipe or a return pipe can be inserted therein, and may be made of a non-liquid-permeable material such as rubber that can expand and contract in the radial direction as shown in the figure. An inflatable portion 2a and a non-expandable liquid-passing portion 2b made of a liquid-pervious material such as cloth having no or little elasticity in the radial direction.
It is composed of The above liquid permeability means that a binder for forming a bulkhead, for example, a resin-based binder such as urethane-based resin or a fast-setting cement-based binder is permeable in an uncured state. Say.

Next, the construction procedure will be described. First,
As shown in FIG. 3A or FIG. 3B, a perforated steel pipe 11 having a predetermined length as shown in FIG.
In the case of (b), finally, the perforated pipe 12 is added, and the reinforcing pipe 1 having a predetermined length is cast. Next, as shown in FIG. 5 (a), an injection pipe 3 for injecting a long gel time solidification material such as a normal cement-based bonding material into the reinforcing tube 1 and filling the packing material into the packer. Hose 4 for injecting a resin-based or fast-setting cement-based binder for forming a bulkhead, an exhaust hose 6 for discharging air from a reinforcing pipe, and the like. The one set at a predetermined position as described above is inserted into the reinforcing tube 1. The front end and the rear end of the packer 2 are fitted around the outer periphery of the injection pipe 3 and the hoses 4 and 6, and are fastened and fixed by a band, a string, or an appropriate fastening means.

In this state, a compaction material is filled into the packer 2 from the packer hose 4 and a compaction material having a relatively short gel time, such as a resin or a fast-setting cement, is used as the compaction material. In this embodiment, urethane resin having a gel time of about 30 to 120 seconds is often injected. Then, in the packer 2 of the present embodiment, as shown in FIG. 5B, the resin-based solidifying material injected into the packer expands the expandable portion 2a made of rubber or the like, and partitions the inside of the reinforcing pipe 1 ( A partition wall is formed, and the resin-based solidifying material is prevented from going deeper than this. Further, by injecting the compaction material into the packer 2 from the packer hose 4, the compaction material G exudes from the non-expandable liquid passing portion 2b made of cloth or the like, and also exudes into the ground around the reinforcing pipe at this position. Then, the partition wall made of the bonding material G is formed.

In this state, the bulkhead forming hose 5
When a binder such as a resin-based or quick-setting cement-based resin having a relatively short gel time is injected into the reinforcing pipe 1 closer to the mouth than the packer 2 through the packing, as shown in FIG. Penetrates into the ground surrounding the steel pipe 11 or the perforated pipe 12 from the small holes 11a provided in the peripheral wall of the steel pipe 11 constituting the reinforcing pipe 1 or the opening 12a of the perforated pipe 12, and is immediately cured. Therefore, the bulkhead forming packer 2
The ground for a predetermined length on the mouth side from the position where is installed is the most loose due to the drilling of the reinforcing pipe 1, and a gap that can serve as a leak path for the consolidated material is formed. Are effectively filled and improved by a resin-based consolidating material having a short gel time, and the bulkhead B is obtained.

Next, as shown by an arrow in FIG. 6A, a cement material having a long gel time, such as a cement-based cement material, is introduced into the reinforcing tube 1 farther from the packer 2 from the hollow binder injection tube 3. Inject at a predetermined pressure. Since the solidification material has a long gel time, it is sequentially filled in the reinforcing pipe 1 without being hardened immediately. At this time, the air in the reinforcing pipe 1 is discharged to the outside from the end of the reinforcing pipe on the mouth side through the exhaust hose 6.

The solidified material which has entered the reinforcing pipe 1 as described above spreads over a wide range from the small through hole 11a formed in the peripheral wall surface of the steel pipe 11 constituting the reinforcing pipe 1 to the inside of the hole and the surrounding ground. Infiltrate When the solidified material in the surrounding ground and the reinforcing pipe 1 is sufficiently filled, the solidified material overflows to the mouth side through the exhaust hose, whereby the solidified material is filled in the reinforcing pipe 1 and the surrounding ground. It is confirmed that the water has sufficiently penetrated the mountain, and in that state, the injection of the consolidation material is stopped.

As described above, the cement-based cement material having good economy and long gel time allows the cement material to penetrate well into a wide area in the ground located on the back side of the packer 2 without being hardened in the middle. The solidification region A is formed to improve the ground. However, when the cement-based solidification material is injected, the loosened ground portion closer to the mouth than the packer is already filled with the resin-based solidification material. As a result, the bulk head B is formed, so that leakage of the cement-based consolidated material having a long gel time and good permeability to the mouth side (face side) is favorably prevented. Therefore, for example, a uniform and reliable ground improvement effect can be obtained without performing the interval injection as described above and over the entire length. In addition, since an appropriate amount of a solidifying material of an appropriate type can be injected into a portion to be injected without causing a leak, economy and workability are good.

In the case of the long precedent construction shown in FIG. 1, the cross section is gradually widened as the tunnel is excavated. However, the rear end (mouth part) of the precedent steel pipe is cut off so that it can be cut off. It is also possible to reinforce the ground without widening. To this end, as shown in FIG. 3 (b), a reinforcing pipe for, for example, one pipe (for example, about 3 m) at the mouth portion may be constituted by a porous pipe 12 made of expanded metal, punched metal, or the like. By doing so, the perforated pipe exposed in the tunnel space as the face moves can be easily cut off by an excavating machine. There is no need to widen the cross section, and the lining concrete to be backfilled can be reduced accordingly. In addition, by using the porous tube 12 as described above, the permeability of the resin-based consolidated material injected into the mouth portion into the ground can be improved, and the bulkhead effect can be further improved.

In the above embodiment, the perforated tube 12
Although a pipe made of expanded metal or punching metal is used as the above, a perforated pipe made of a synthetic resin may be used, or a perforated pipe made of a synthetic resin may be used instead of the steel pipe 11.

Further, in the above-described embodiment, an example in which the present invention is applied to the pre-receiving work of the tunnel is shown. It is also possible to apply to various ground reinforcement methods including slope stabilization using pipes.

Further, in the above-described embodiment, the inflatable portion 2a and the bulkhead region into which the resin-based binder having a short gel time is injected and the region into which the binder having a long gel time is injected are separated from the bulkhead region. Although the bulkhead forming packer 2 having the non-expandable liquid passage portion 2b is used, the configuration of the packer 2 is configured as long as it can appropriately partition both different regions of the consolidated material. No problem. For example, a configuration in which a simple partition plate is installed in a steel pipe may be used. In some cases, the above-described packer, partition plate, and the like can be omitted.

[0029]

As described above, according to the present invention, in the ground reinforcement method using a reinforcing material using a reinforcing pipe, a short gel time consolidation is performed in the ground corresponding to the mouth of the reinforcing pipe. Since a bulkhead made of a material is formed and a consolidated material with a long gel time is injected into the back side, a consolidated material with a long gel time is prevented while preventing leakage to the mouth side by the bulkhead. It can penetrate the ground in a wide area and reinforce the ground. For example, it is possible to obtain a uniform and reliable ground improvement effect over the entire length without performing the interval injection as described above. In addition, since the amount of the relatively expensive consolidating material having a short gel time can be reduced, the construction can be performed at a low cost.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of a ground reinforcement method according to the present invention.

FIG. 2 is an enlarged view of a part thereof.

FIGS. 3A and 3B are explanatory diagrams showing a configuration example of a reinforcing pipe.

FIG. 4 is a partial vertical side view of a bulker forming packer.

FIG. 5 is an explanatory view of the construction procedure of the ground reinforcement method according to the present invention.

FIG. 6 is an explanatory view of a construction procedure of the ground reinforcement method according to the present invention.

FIG. 7 is a cross-sectional view of a schematic configuration showing an example of a conventional ground reinforcement method.

FIG. 8A is a cross-sectional view of a part of a conventional ground reinforcement method.
(B) is the longitudinal front view. (C) is c- in (a).
c line enlarged sectional view.

FIG. 9 (a) is an explanatory view of a state in which a binder is injected by a continuous batch injection method. (B) is an explanatory view of the state of the solidification material injection by the interval injection method.

FIG. 10 (a) is an explanatory view showing a state of leakage of a consolidated material by a continuous batch injection method. (B) is an explanatory view showing a leak state of the consolidated material by the interval injection method.

[Description of Signs] 1 Reinforcement pipe 11 Steel pipe 12 Perforated pipe 2 Packer 2a Expandable part 2b Non-expandable liquid passage part 3 Consolidating material injection pipe 4 Packer hose 5 Resin hose 6 Exhaust hose 6 A Solidification area B Bulkhead T Tunnel Space R Shoring W Face mirror M Ground mountain h Drilling

Continuing from the front page (72) Inventor Takumi Eguchi 2-5-10 Shiba, Minato-ku, Tokyo Inside KFC Corporation (72) Inventor Kenichi Igarashi 2-5-10 Shiba, Minato-ku, Tokyo F-sea F-term (reference) 2D040 AA06 AB01 AB14 BB09 CA01 CA10 CC02 CC03 DA03 DA12 DC02 2D054 AC20

Claims (3)

[Claims] 1. A method for reinforcing a ground material using a solidification material using a reinforcing pipe, wherein a solidified material having a short gel time is applied to a solid ground in a region corresponding to a predetermined length of a mouth portion with respect to the entire length of the reinforcing pipe. Forming a bulkhead, injecting a solidified material having a long gel time into the back side of the portion where the bulkhead is formed, and preventing a leak to the mouth side by the bulkhead, while forming a solidified material having a long gel time. Is a method of reinforcing the ground by infiltrating the ground with a wide range of ground. 2. A cement-based material having a short gel time, a resin-based or fast-setting cement-based material having a gel time of less than 2 minutes, and a cement material having a long gel time having a gel time of 30 minutes or more. 3. The method of reinforcing a ground mountain according to claim 1, wherein a binder is used. 3. The ground reinforcement method according to claim 1, wherein a packer is provided in a reinforcement pipe corresponding to a predetermined length position of the mouth portion.