JPH0235086B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a grouting method and apparatus using a grouting pipe having a consolidation projection.

Currently, the mainstream method for grout injection is double-pipe drilling rods, and some have proposed double-channel pipes, while the other methods include single injection of slow-setting or instant-setting grout. In addition, a composite grouting method that uses these methods in combination has also been proposed.

Looking back at the conventional equipment and construction methods, the outer circumferential surface of the injection tube was flush with no protrusions. Moreover, if there is a protrusion on the circumferential surface, it becomes a resistance during drilling, and the drilling device has to be made larger accordingly.

On the other hand, considering the history of the construction method, instead of the slow-setting method in which permeable grout is injected over a long period of time, the so-called
The double pipe instant connection method, represented by the LAG method, has made great progress, and the current situation is that composite construction methods that take advantage of the characteristics of both methods are being proposed.

In any case, when injecting slow-setting grout, the main objective is to inject it into the surrounding ground at low pressure and low speed, and when injecting instant-setting grout, the main purpose is to prevent the grout from escaping toward the base end. The purpose is to inject into a limited area while preventing the grout from developing a packing effect.

The present inventors fundamentally reviewed the conventional construction method, and found that the original purpose of grout injection, whether instant setting or slow setting, was to minimize the deformation of the injection pipe structure, as will be detailed later. By devising construction procedures,
I have found that it is completely achievable. Furthermore, as mentioned above, the conventional idea that providing a protrusion on the injection pipe would increase the size of the drilling device, which would be disadvantageous in terms of workability and economic efficiency, is completely unfounded. It also became clear. Furthermore, it has been found that by raising the injection pipe having projections, it is possible to obtain an unexpected effect of simultaneously accomplishing the consolidation of the grout pack and the securing of the injection gap between the surrounding ground.

The present invention will be explained below using specific examples shown in the drawings.

FIGS. 1a to 1f show the lifting method according to the present invention in the order of construction. Prior to construction, in the present invention, an overhang height d of about 0.5 to 10 mm is preferably provided on one side of the peripheral wall of the injection tube 1, for example, at a height of 5 to 100 cm, preferably 5 to 50 cm from the tip.
A protrusion 2 having an integral shape is used.

First, as shown in Fig. a, while applying rotational force and pressure force to the injection pipe 1, drilling water W is fed and discharged from the spout 3 at the tip, and the drilling 4 is extended to a predetermined depth in the target ground. I do.

Next, at that point, as shown in Figure b, instant-setting grout S1 with a short gel time is injected into the surrounding ground through the injection pipe 1 through the injection port 5, which has been formed in advance on the circumferential wall slightly closer to the tip than the protrusion 2. , injection tube 1
Injection into a limited area around the hole 4 and filling between the hole 4 and the injection pipe 1 is performed.

Thereafter, with the injection tube 1 in the chuck state, it is pulled up to a predetermined length, preferably 5 to 50 cm, as shown in Fig. c, using a known injection tube installation machine. As a result, the instant setting grout S1 filled in the gap is consolidated by the protrusions 2, and depending on the ground conditions and the type of grout, some of the instant grout S1 is pressed radially around the injection pipe 1. Therefore, the packer effect caused by the instant setting grout S1 appears even more prominently. At the same time, due to the upward movement of the protrusion 2, a guided injection hole H ₀ is formed after its movement path.

Next, in this state, the slow-setting grout L1 with a long gel time is fed into the injection pipe 1 as shown in Figure d, and slowly injected into the surrounding ground from the injection port 5. The loosely setting grout L1 discharged from the injection port 5 is empty.
Since the H ₀ is preformed, it is injected into the surrounding ground at a low pressure and at a low velocity, breaking through or passing through the grout S1 zone, and injecting it more slowly.

Thereafter, as shown in Fig. e, the instant-setting grout S2 is again fed into the injection pipe 1 and injected from the injection port 5, thereby creating a new packer zone S2 mainly above the packer zone S1. However, in this case, grout S
2 is while breaking the existing sealer zone S1 or between the sealer zone S1 and the outer surface of the injection pipe.
Passes through and forms the Patscar zone above the Patscar zone S1, but the Patscar zone S
2 may be difficult to create, it is preferable that the injection port 5 be located in the patcher zone S, as shown in e' in Fig. 8.
It is preferable to further pull up the injection tube 1 after step d until it reaches the position above 1, and then inject the instant setting grout S2 from the injection port 5.

Next, as shown in Fig. f, the injection pipe 1 is again pulled up a predetermined length to compact the grout S2 newly filled in the space and to form a new void _H0 .
In this state, slowly setting grout L2 is injected.

Thereafter, the steps of lifting the injection pipe, (if necessary) → injection of instant setting grout → pulling up the injection pipe → injection of slow setting grout are repeated.

Figure 2 shows an example of the forward type. First, as shown in figure g, while applying rotational force and pressurizing force to the injection pipe 1,
The hole is drilled to a predetermined depth while being fed.

Thereafter, instant setting grout S1 is injected at a predetermined position as shown in Fig. h, and then the injection pipe 1 is pulled up to a predetermined length as shown in Fig. Secure H ₀ . Furthermore, as shown in Figure J, slowly setting grout L1 is injected.

The steps up to this point are essentially the same as the steps shown in FIGS. 1a to 1d for the pull-up type. In the advance type shown in Fig. 2, after injection of the slow-setting grout L1 shown in Fig. J is completed, rotational force and pressing force are applied to the injection pipe 1, and a hole is drilled to the front of the injection zone of the slow-setting grout L1. ,
As shown in figure k, the instant setting grout S2 is again injected to create a grout S2 zone in front of the grout S1 zone, and the void formed by the forward movement of the protrusion 2 is filled with grout S2. do.

Next, the injection pipe 1 is pulled up to a predetermined length as shown in Fig. 1, the filling grout S2 is compacted and a void _H0 is formed, and then the slow-setting grout L2 is injected.

Thereafter, the following steps are repeated: forward drilling → injection of instant setting grout → pulling up the injection pipe → injection of slow setting grout.

Here, especially in the case of the above-mentioned pull-up type, the injection pipe itself is not used as a drilling rod, but after the injection pipe is placed in a hole drilled by an appropriate drilling machine,
It is also possible to adopt subsequent steps. Furthermore, in all of the above examples, the quick-setting grout is first injected, then pulled up, and then the slow-setting grout is injected. It is also possible to inject only with a grout of the same type as the grout. Alternatively, the type of grout suitable for the characteristics of the ground may be selected for each step.

However, in general, as in each of the above examples, it is preferable to first fill the area around and between the injection pipes with fast-setting grout and use this as a packer; conversely, use slow-setting grout. Even if it is injected, the Packer effect is small and there is a risk that it may escape toward the proximal end. However, if slow-setting grout is injected before the injection tube is pulled up, and then the injection tube with projections is pulled up according to the present invention, the slow-setting grout in the middle will be slightly consolidated, so the conventional projection Compared to lifting and injecting slow-setting grout using an injection tube that does not have an injection tube, the effect is considerable.

On the other hand, even when instant-setting grout is injected into the void created by pulling up an injection pipe with protrusions, while filling the void with instant-setting grout,
Since the empty hole wall is injected as if it were one large inlet, it affects the surrounding soil particles.
The injection is performed at low pressure and at a low speed, allowing for easy injection without causing any upheaval of the ground. However, the void created by pulling up the injection tube with projections has the greatest effect when slowly setting grout is to be injected. In other words, when slow-setting grout is discharged into the air from the inlet at a low discharge rate and speed, the speed and pressure of the slow-setting grout decreases rapidly as it faces the air, and in this state it penetrates between soil particles. Injected. Therefore, the long-awaited original penetration injection is achieved.

In order to achieve penetration injection, in addition to the conventional so-called strainer method, an inner pipe is installed at the tip of the injection pipe so that it can be moved in and out, and after drilling, the entire injection pipe is pulled up.
A construction method is being considered in which the inner tube is then pushed out and the outer tube is pulled up, and then grout is injected through the injection space created. However, an injection tube with a complicated structure is required to allow the inner tube to enter and exit, and the operation is also extremely complicated. Moreover, in this construction method, instant setting grout is injected into the surrounding ground through the injection space in advance,
After that, the instant setting grout is broken and the slow setting (permeable) grout is injected, so the injection space that has been painstakingly created is not fully utilized, and there is also an intention to slowly inject the permeable grout. From the perspective of the result of the phenomenon, it is unexpected. In contrast, in the present invention, the structure is simple because the protrusion is simply formed on the injection pipe, and the construction can be carried out by simply pulling up the entire injection pipe in the usual manner using a normal injection pipe installation machine. It is extremely simple and can reliably achieve the original osmotic injection.

By the way, also, Fig. 1 b → d or Fig. 2 h
In the process of →j, grout may be injected while pulling up the injection pipe. In this case, a cavity is formed and grout is injected through the cavity. Furthermore, in any case, it is better to pull up the injection tube without rotating than to pull it up while rotating, since this will prevent the gap between the injection tube and the grout filling around it. This is a preferable embodiment as there is no outflow of grout from the bottom to the proximal end side. In addition, for injection, it is better to form a plurality of injection ports in the circumferential direction and/or the longitudinal direction, or to use an annular injection port as in the later example of the device, to achieve more homogeneous injection than one injection port. If necessary, a large number of small holes may be formed like a strainer tube. If the injection port is a single hole in the peripheral wall, the injection tube may be rotated during injection.

The position of the injection tube is not necessarily limited. For example, as shown in Fig. 3, an injection port 5 is formed on the peripheral wall on the distal end side from the protrusion 2, and each grout is discharged from there. Inlet 5' formed on the proximal side
Therefore, the slow-setting grout may be injected through the injection port 5 formed on the tip side of the protrusion 2. Furthermore, as shown in FIG. 5, the spout 3 at the tip of the injection tube 1 may be used as an injection port. However, since one of the objects of the present invention is to inject grout into the cavity formed by the protrusion 2, at least one injection port is provided on the tip side of the protrusion 2 in any case. It is necessary.

Furthermore, as is clear from FIG. 5, the protrusion 2 may be provided at the tip of the injection tube 1. Although not shown, there may be a plurality of protrusions spaced apart in the longitudinal direction of the injection tube.

On the other hand, it is desirable to select the type of grout to be injected that is compatible with the properties of the target ground.
The instant setting grout used for the pack effect and limited area injection is preferably one whose gel time is within 30 seconds, particularly about 1 to 10 seconds. As a slow setting grout intended for penetrating injection, one that lasts for 1 minute or more, particularly about 3 minutes to 200 minutes, is preferable.
The actual manner of injection into the ground is not necessarily determined solely by the gel time, and it also varies depending on the grout composition and ingredients, but it is usually sufficient to control the gel time. many.

By the way, in the present invention, at the same time as the grout in the upper part is compacted by the protrusion as the injection pipe is pulled up, the grout is slowly loosened through the guide gap formed below, and it is particularly preferable to gradually inject slowly setting grout. This is one of our major objectives. Therefore, grout injection from the injection port on the tip side of the protrusion is not suitable at high pressures that disturb the ground, and it is necessary to maintain a low pressure of 50Kg/cm ² or less, especially 20Kg/cm ² or less. It is said that Note that this pressure is the pressure at the injection port. Therefore, the pressure that attempts to penetrate between the soil particles through the induction gap will become even smaller. However, the infiltration pressure gradually increases over time.

In addition, in the case of the forward type, although it has the advantage of always fully exhibiting the Packer effect, it is often inferior in construction speed and construction economy, so the pulling type is more advantageous in terms of ease of construction.

Furthermore, the internal structure of the injection pipe may be a single pipe, but when injecting two-component hardening materials, especially instant-setting grout, double-channel pipes (polymerized pipes or parallel It is preferable to introduce each liquid independently and have them join, come into contact, and mix for the first time near the injection port inside the injection tube, or to have them meet and come into contact outside the injection tube.

FIGS. 6 and 7 show examples of optimal injection tube tips. FIG. 6 shows the state during drilling, and FIG. 7 shows the state during injection.

This injection tube 1 basically has a double tube structure, and an outer joint tube 11 is disposed at the tip of the outer tube 10 with an injection port 5 continuously opened in the circumferential direction between the end faces. A tip tube 14 having a hole drilling bit 12 is threadedly connected to this outer joint tube 11, and the tip thereof serves as a spout 3. The outer tube 10 is threadedly connected to a double outer tube (not shown).

Inside the outer tube 10 and the outer joint tube 11, a middle tube 16 that connects them is screwed and fixed, and a spool tube 18 is installed inside the outer tube 10 and the middle tube 16. An inner joint pipe 20 is fitted to the base of the spool pipe 18, and a projection portion 20a of the inner joint pipe 20 is fitted into the base of the spool pipe 18.
is adapted to be inserted into an inner tube of a double tube (not shown). The inner joint pipe 20 is fitted into the outer pipe 10 through, for example, three overhangs 20b extending in the radial direction, and a seat 20c is integrally provided inside the inner joint pipe 20. A check valve 24 biased by a spring 22 having a seat 20c as a seat closes the inner flow path of the joint pipe 20.

Thus, one of the liquids delivered from the ground is
enters the inner joint pipe 20 through the inner pipe of the double pipe,
The other liquid passes through the space between the double outer tube and the inner tube and heads towards the tip, and passes between the outer tube 10 and the inner joint tube 20 between the overhanging strips 20b and heads toward the tip. It's becoming like that.

A side portion 18a is formed in the spool tube 18, and a spring 22 is formed between this side portion 18a and the end of the middle tube 16.
6 is interposed therebetween, and the spool tube 18 is normally moved toward the proximal end by the spring 26. A discharge port 18b is formed in the radial direction in the narrow diameter portion at the tip of the spool tube 18, and a plurality of communication holes 18c are formed in the radial direction on the base end side. 6), it is closed by a middle cylinder 16.

Furthermore, an annular projection 2 is fixed by welding or the like to the proximal end side of the injection port 5 formed between the end faces of the outer tube 10 and the outer joint tube 11. Protrusion 2
Alternatively, there may be a plurality of them discontinuously in the circumferential direction to the extent that the grout can be consolidated. If necessary, another protrusion may be provided further proximally than the protrusion 2.

The part of the middle cylinder 16 that corresponds to the injection port 5 is a small diameter part, and the small diameter part and the outer pipe 10 and the outer joint pipe 11 are connected to each other.
An annular mixing chamber 28 is formed between the two. Furthermore, facing both ends of the annular mixing chamber 28, a plurality of outer channel liquid discharge ports 16a and inner channel liquid discharge ports 16b are formed in the circumferential direction passing through the middle cylinder 16, respectively.

Now, when drilling water W is forced into the inner pipe of the injection pipe during drilling, the drilling water W will cause the check valve 24 to close to the spring 22.
Pass through the joint tube 20 while pushing down overcoming the urging force of
It passes through the inside and is ejected forward from the ejection port 3.

During injection, liquids A and B are sent between the inner tube and the outer tube. The feeding pressure of liquid B, which is the external channel liquid, acts on the shoulder of the spool tube 18, and as a result, the spring 26 is compressed, and the spool tube 18 moves toward the distal end. Thereby, the B liquid passes through the gap between the spool pipe 18 and the outer pipe 10, and the outer channel liquid discharge port 16a opened by the movement of the spool pipe 18.
into the mixing chamber 28 and toward its center. At this time, as the spool pipe 18 moves, its tip fits into the middle cylinder 16 and closes it, so that after passing through the inside of the spool pipe 18, the liquid A passes through the communication hole 18c.
pass through. Then, as the spool pipe 18 moves, the communication hole 18c communicates with the inner channel liquid discharge port 16b, so that liquid A further enters the mixing chamber 28 through the discharge port 16b and heads toward the center.

In the mixing chamber 28, both the AB liquids meet in a countercurrent manner, come into contact with each other, and are mixed to form a homogeneous mixed liquid, which is injected into the surrounding ground from each injection port 5, 5, . . . .

Here, especially when injecting slow-setting grout, the mixed liquid that has already been combined in the Y-shaped pipe at the proximal end of the injection tube is mixed in the same manner as the flow of the drilling water W described above, without being discharged from the injection port 5. It may also be injected from the spout 3. In this way, slow-setting grout can be injected from the spout 3, and fast-setting grout can be injected from the injection port 5.

When selecting injection ports depending on the type of grout, there are protrusions between the injection ports, as shown by the imaginary lines in Figures 4 and 6 (the protrusions are numbered 2'). It is better to do this.

As described above, according to the present invention, despite the simple structure of just forming protrusions on the peripheral wall of the injection pipe, it is possible to mechanically consolidate the grout and at the same time secure the guided injection gap, resulting in an unexpectedly effective injection is possible.

[Brief explanation of drawings]

Figures 1 a to f are schematic diagrams sequentially showing the construction method of the pull-up type of the present invention, Figures 2 g to l are schematic diagrams of the advancing type, and Figures 3 to 5 are various inlet positions. Fig. 6 is a cross-sectional view showing only the tip of the injection tube that is most suitable for carrying out the method of the present invention and shows the state during drilling, and Fig. 7 shows the state during injection. The sectional view and FIG. 8 are schematic diagrams showing only the main steps of another example of the pull-up type. 1...Injection pipe, 2...Protrusion, 3...Spout port, 5
... Inlet, S1, S2 ... Instant setting grout, L
1, L2...Low setting grout, _H0 ...Guided injection void.

Claims (1)

[Scope of Claims] 1. A protrusion is integrally provided on the peripheral wall of the injection tube, and one or more injection ports are formed in the injection tube, and at least one of the injection ports is formed on the distal side of the protrusion, With this injection pipe inserted into the ground, grout is injected from either injection port, and then, while or after pulling the injection pipe up a predetermined length, grout of the same type or different type as the grout is injected at a low pressure of 50 kg/cm ² or less. A grout injection method characterized by injecting at least from an injection port on the tip side of the protrusion. 2. The grout injection method according to claim 1, wherein the injection pipe is a drilling rod, and the holes are drilled using the injection pipe. 3. The grout injection method according to claim 1, wherein the injection pipe is not rotated when the injection pipe is pulled up and when injection is performed from the injection port on the tip side of the protrusion. 4. The grout injection method according to claim 1, wherein the injection tube is rotated around its axis when the injection tube is pulled up and when the injection tube is poured from the injection port on the tip side of the protrusion. 5. The grout injection method according to claim 1, wherein grout with a short gel time is injected into the upper part of the protrusion in a step before pulling up the injection pipe. 6. The grout injection method according to claim 1, wherein permeable grout is injected into the void formed as the injection pipe is pulled up. 7. A protrusion is integrally provided on the peripheral wall of the injection pipe, and at least one injection port is formed on the tip side of the injection pipe, and the injection pipe is installed in the ground. Inject the first grout from either injection port with the grout inserted, then while or after pulling the injection tube up a specified length to the next step, apply a low pressure of 50 kg/cm ² or less to the injection port on the tip side of the protrusion. A second grout of the same type or a different type from the first grout is injected from the grout, and then the first grout is injected from either of the inlets in the next step or the step in which the injection tube is pulled up, and then in the step or the next step A grout injection method characterized by injecting a second grout at a pressure of 50 kg/cm ² or less from an injection port on the tip side of the protrusion during or after raising the protrusion to the step. 8. Inlet ports are formed on the distal and proximal sides of the protrusion, and the proximal inlet serves as the first grout inlet and the distal inlet serves as the second grout inlet. Grout injection method described in section. 9. The grout injection method according to claim 7 or 8, wherein the first grout is a grout with a short gel time, and the second grout is a permeable grout. 10 A protrusion is integrally provided on the peripheral wall of the injection pipe, one or more injection ports are formed in the injection pipe, and at least one of the injection ports is formed on the tip side of the protrusion, and this injection pipe is installed in the ground. Inject the first grout from either injection port in the inserted state, and then while or after pulling up the injection pipe a predetermined length,
Inject the second grout of the same type or different type as the first grout from the injection port on the tip side of the protrusion at a low pressure of 50Kg/cm ² or less, then move the injection tube forward from the initial position and then insert it into either injection port. After injecting the first grout, the injection pipe is pulled up a predetermined length to a position substantially below the already injected second grout zone, or after being pulled up, the injection tube is placed at a low pressure of 50 kg/cm ² or less on the tip side of the protrusion. A grout injection method characterized by injecting a second grout from an inlet. 11. A grout injection device characterized by having a consolidation protrusion integrally provided on the peripheral wall of the injection pipe to perform a consolidation action on the ground when the injection pipe is pulled up, and having an injection port on the tip side of the protrusion. 12. The grout injection device according to claim 11, which has an injection port on the distal end side and the base end side of the protrusion.