JP6150387B2 - Ground injection device - Google Patents

Description

  The present invention relates to a technique for performing ground improvement by injecting a ground injection material (injection chemical liquid, cement milk, etc.) into the ground to be improved.

In this technology (ground injection method), a ground injection device is inserted into a borehole filled with a sealing material (for example, cement bentonite solution), and the ground injection material is injected from the ground injection device to the ground to be constructed. It was.
Cracks are formed in the solidified sealing material due to the pressure of the ground injection material sprayed from the ground injection device, and the ground injection material reaches the area outside the borehole in the radial direction via the crack. Injected into the ground to be done.
In addition, when replacing with a ground injection material and injecting water and generating a crack in a sealing material, the ground injection material is injected after crack generation.

In the ground injection method, it is desirable to continuously generate cracks in the longitudinal direction of the sealing material and continuously inject the ground injection material in the vertical direction of the ground to be improved.
However, in the prior art, it was difficult to continuously generate cracks in the longitudinal direction of the sealing material.
Therefore, in the prior art, it is necessary to form a large number of ground injection material injection ports intermittently (for example, at a pitch of 33 cm) in the longitudinal direction (vertical direction) of the tubular member of the ground injection device.

In the prior art, the ground injection material is not uniformly injected into the ground at 360 ° with respect to the horizontal section, and it may be difficult to form a crack in the solidified sealing material.
Therefore, in the prior art, the region where the ground injection material is injected into the ground is biased, and it is difficult to improve the quality of the ground improvement by the ground injection method.

As another conventional technique, there is a technique for injecting a non-alkaline silica solution to prevent deterioration of concrete and maintain water quality (see Patent Document 1).
However, the related art (Patent Document 1) does not intend to solve the above-described problems of the prior art.

JP 2011-241684 A

  The present invention has been proposed in view of the problems of the prior art described above, and in the region where the ground injection material is to be injected, a crack (split) is continuously formed in the seal material in the vertical direction, and the vertical direction. An object of the present invention is to provide a ground injection device capable of continuously injecting a ground injection material.

The ground injection device (10) of the present invention includes an injection pipe (vinyl chloride pipe 1), a pair of elastic mold members (rubber mold material 2) covering its outer peripheral part (1o), and a pair of elastic mold members (rubber). A heat-shrinkable member (heat-shrinkable tube 3) is provided on the outer periphery (2o) of the molding material 2), and a through-hole (1h: perforated hole: for example, longitudinal direction) is provided in the injection tube (vinyl chloride pipe 1). A pair of elastic molds (rubber mold 2) are fitted from both ends of the injection tube (1) and cover the through hole (1h), A groove (2c) extending in the longitudinal direction is formed in the outer peripheral portion (2o) of the pair of elastic mold members (2), and a slit (3s) is formed in the heat-shrinkable member (3). It is characterized by that.

In the present invention, the slit (3s) formed in the heat-shrinkable member (3) is preferably formed at a position corresponding to a location where a crack is formed in the solidified sealing material.
And it is preferable that the slit (3s) formed in the heat-shrinkable member (3) is intermittently formed in the longitudinal direction (vertical direction).

The ground injection device of the present invention preferably has a polygonal cross section (triangle to dodecagon).
Here, the term “polygon” in the present specification is a term that includes not only a regular polygon but also a polygon that is not a regular polygon.
The ground injection device of the present invention preferably has a circular or elliptical cross-sectional shape.

According to the present invention having the above-described configuration, the injection material flowing in the injection pipe (vinyl chloride pipe 1) is formed in the through-holes formed therein (perforated holes 1h: for example, a plurality of locations in one cross section). From the outer peripheral surface (1o) of the injection tube (1) and the inner peripheral surface (2i) of the pair of elastic mold members (rubber mold members 2) in the longitudinal direction and the circumferential direction. The pair of elastic mold members (2) covered from both ends of the injection pipe (1) flows out radially outward from an annular gap (boundary B) formed at the ends facing each other.
The injection material (arrow F3) that flowed radially outward from the annular gap (boundary B) between the ends in the longitudinal direction of the pair of elastic mold members (2) in the circumferential direction is the elastic mold material (2). The groove (2c) flows in the longitudinal direction (vertical direction in FIG. 1), and from the groove (2c), the outer peripheral surface (2o) of the elastic mold member (2) and the inner peripheral surface (3i) of the heat-shrinkable member (3). In the circumferential direction (arrow F4). And it inject | pours in the ground (G) from the slit (3s) formed in the predetermined location of the heat-shrinkable member (3) (arrow F5).
According to the present invention, the injection material (injection chemical solution) flows through the groove (2c) formed in the outer peripheral portion (2o) of the pair of elastic mold materials (rubber mold material 2). Even if a large number of through-holes are not drilled in the longitudinal direction of 1), the injection material moves over a wide range in the vertical direction (longitudinal direction), and the injection material discharge section length (Lj: see FIG. 1) It is injected into the ground over the entire area.

According to the present invention, the heat-shrinkable member (3) has a location corresponding to a location where a crack (split) is to be formed in the solidified sealing material (20: for example, cement bentonite solution) in the borehole (H). Further, since the slit (3s) is formed, the injection material can apply injection pressure from the slit (3s) into the seal material (20). Therefore, stress concentration can be generated at a desired location, and cracks (splits) can be reliably formed continuously in the vertical direction.
Therefore, in the heat-shrinkable member (3), by appropriately adjusting the position where the slit (3s) is formed, it is possible to prevent the location where the crack (split) is formed from being biased.

According to the present invention, the injection material flows in the groove (2c) formed in the outer peripheral portion (2o) of the pair of elastic mold materials (rubber mold material 2), and has an injection material discharge section length (Lj: see FIG. 1). Since the injection is performed throughout, even when the injection material discharge section length (Lj: see FIG. 1) is changed, the pair of packer (30) intervals in the injection inner tube (40) of the injection device (10) There is no need to change. Therefore, even when the injection material discharge section length (Lj: see FIG. 1) is changed, it is not necessary to change the injection inner pipe (40).
Even if there are many types of injection material discharge section lengths (Lj: see FIG. 1), it is not necessary to prepare multiple types of injection inner pipes (40) in the present invention.

According to the present invention, since the elastic mold member (rubber mold member 2) itself has elasticity (elastic force acting in the direction of tightening the injection tube), the inner peripheral surface (3i) of the heat-shrinkable member (3). And a check valve against the flow of the injection material flowing between the outer peripheral surface (2o) of the elastic mold member (2). Similarly, it acts as a check valve against the flow of the injection material flowing between the outer peripheral surface (1o) of the injection pipe (1) and the inner peripheral surface (2i) of the elastic mold member (2).
Even if the injection material injected into the ground tries to flow backward and tries to expand the region between the heat-shrinkable member (3) and the elastic mold material (2), it is hindered by the elastic repulsion of the elastic mold material (2). It is difficult for the injection material to flow backward in the region between the heat-shrinkable member (3) and the elastic mold material (2).
Similarly, since the elastic mold member (2) exerts an elastic force in the direction in which the injection tube (1) is tightened (inward in the radial direction), the injection member is in contact with the outer peripheral surface (1o) of the injection tube (1) and the elastic mold member (2 In order to reversely flow between the inner peripheral surfaces (2i), the elastic force must be opposed to the inner peripheral surface (2i), and such a reverse flow is difficult.
Therefore, according to the present invention, it is difficult for the injection material injected into the ground to flow backward and reach the hole (1h) drilled in the injection pipe (1), and the backflow prevention performance of the injection material is improved. ing.

  Here, since the elastic mold member (2) exerts an elastic force inward in the radial direction, the elastic mold member (2) and the injection tube (1) are in close contact with each other. However, since the elastic mold member (2) has elasticity due to elasticity, the injection material that has flowed radially outward from the through hole (1h) drilled in the injection tube (1) is the outer peripheral surface of the injection tube (1). When trying to flow between (1o) and the inner peripheral surface (2i) of the elastic mold member (2), the elastic mold member (2) expands (moves) radially outward even if the pressure of the injection material is not high. To do. Therefore, even if the pressure of the injection material is not high, the injection material can surely flow between the outer peripheral surface (1o) of the injection tube (1) and the inner peripheral surface (2o) of the elastic mold member (2).

According to the present invention, since the elastic mold member (2) exerts an elastic force inward in the radial direction, when the heat-shrinkable member (3) is covered, the elastic mold member (2) and the injection tube (1) The correct position will not be shifted.
Therefore, the assemblability is also improved in the present invention.

It is a longitudinal section showing a 1st embodiment of the present invention. It is sectional drawing which shows the ground injection apparatus which concerns on 1st Embodiment. It is a figure which shows the assembly process of the ground injection apparatus which concerns on 1st Embodiment. It is XX arrow sectional drawing of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of this invention. It is a perspective view of the rubber-made mold material used in 2nd Embodiment of this invention. It is explanatory drawing which shows an example of the construction by 1st Embodiment and 2nd Embodiment. It is explanatory drawing different from FIG. 7 which shows a construction example.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, a first embodiment will be described with reference to FIGS.
In FIG. 1, the ground injection device 10 according to the first embodiment is disposed in a region (construction region) that is already filled with the sealing material 20 in a borehole H drilled in the ground G. Then, an injection solution (injection material, injection chemical solution) is discharged from the ground injection device 10 to the construction area 20.
As will be described later, in FIG. 1, the injected liquid to be discharged is displayed by a thick arrow F5, but only a part of the arrow F5 is displayed for simplification of illustration. The injected liquid is discharged at all locations indicated by the white arrow IF5 in FIG. Also in FIG. 4, in order to prevent the complication of illustration, only a part of the flow of the injection solution is illustrated.

In the injection tube 1 in the ground injection device 10, an injection inner tube 40 fitted with a pair of packers 30, 30 is inserted.
In FIG. 1, the axial dimension Lp indicates the distance between the centers of the pair of packers 30 and 30, and the symbol Lj indicates the injection material discharge section length.

Next, based on FIG. 2, the structure of the ground injection | pouring apparatus 10 is demonstrated with reference also to FIG.
In FIG. 2, the ground injection device 10 includes an injection tube 1 disposed radially inward, an elastic mold member 2 positioned radially outward of the injection tube 1, and a radially outward direction of the elastic member 2. A heat-shrinkable member 3 is provided.
For example, a vinyl chloride pipe is used as the injection tube 1. As shown in FIG. 2, through holes 1 h are formed at eight positions at equal intervals in the circumferential direction of the injection tube 1. Here, as shown in FIG. 3A, the through hole 1h is drilled in the circumferential direction at two locations near the center in the longitudinal direction of the injection tube 1 (vinyl chloride pipe).

The elastic mold member 2 is made of an elastic material, and is made of rubber in the illustrated embodiment. The elastic mold member 2 has a substantially hollow cylindrical shape, and six grooves 2c parallel to the longitudinal direction (axial direction) are formed on the outer periphery of the elastic mold member 2 at an equal pitch in the circumferential direction.
The diameter of the inner periphery 2 i of the elastic mold member 2 is slightly smaller than the diameter of the outer periphery 1 o of the injection tube 1.
As shown in FIG. 3B, a pair of elastic mold members 2 are provided, and the longitudinal direction (axial direction) length of the pair of (two) elastic mold members 2 is the longitudinal direction (axial axis) of the injection tube 1. The direction is set to a length sufficient to cover the through-hole 1h of the injection tube 1 with respect to the length (see FIG. 1).

The heat-shrinkable member 3 is formed in a hollow cylindrical shape, and has a uniform pitch in the longitudinal direction (axial direction) and at equal intervals in the circumferential direction (in the illustrated embodiment, six locations in the circumferential direction). 3s) is formed.
The diameter of the inner periphery 3i of the heat-shrinkable member 3 before applying heat is set larger than the diameter of the outer periphery 2o of the elastic mold member 2 in a state where the elastic mold member 2 is attached (fitted) to the injection tube 1.
As will be described later, when the ground injection device 10 is assembled and the heat-shrinkable member 3 is heated, the heat-shrinkable member 3 contracts and the outer periphery 2o of the elastic mold member 2 is tightened.

Next, with reference to FIG. 3, the assembly method of the ground injection apparatus 10 which concerns on 1st Embodiment is demonstrated.
In the injection tube 1 shown in FIG. 3A, a pair of elastic molds 2 and 2 are fitted from both ends in the longitudinal direction (of the injection tube 1) in the step of FIG. 3B (see arrows S1 and S2). ).
Although not shown, it is preferable to chamfer the corners at both ends of the inner peripheral surface of the elastic mold member 2. This is because if such chamfering is performed, the elastic mold member 2 can be easily fitted into the injection tube 1 as indicated by arrows S1 and S2.

3 (C), the heat-shrinkable member 3 is fitted into the elastic mold member 2 after the step (B), and the heat-shrinkable member 3 is heated. The heat-shrinkable member 3 is heat-shrinked and is in close contact with the outer periphery 2o of the elastic mold member 2. 3 (C) and 3 (D) show the boundary B and the groove 2c. However, after the heat-shrinkable member 3 is covered, the boundary B and the groove 2c are not visible from the outside in the actual machine. I can't. In other words, the boundary B and the groove 2c are shown in FIGS. 3C and 3D for explanation.
When the ground injection device 10 is used, as shown in FIG. 3D, an injection inner tube 40 equipped with a pair of packers 30 and 30 is inserted into the injection tube 1. Here, the step (D) of FIG. 3 is performed at the time of construction, but can also be performed when the ground injection device 10 is manufactured.
In FIG. 3D, reference numeral 31 indicates a support member for the packer 30 on the tip side (in the case of construction), and reference numeral 32 indicates a support member for the ground-side packer 30. The injection inner tube 40 is formed with an injection material discharge hole 32h.

Next, with reference to FIG. 1 and FIG. 4, the ground improvement construction method using the ground injection apparatus 10 of 1st Embodiment is demonstrated.
As shown in FIG. 1, the ground injection device 10 is arranged in a region that is already filled with the sealing material 20 in the borehole H drilled in the ground G.

In the injection tube 1 in the ground injection device 10, an injection inner tube 40 fitted with a pair of packers 30, 30 is inserted. The pair of packers 30 and 30 expands when high-pressure air is supplied via an air pipe (an air pipe for expanding and contracting the packers 30 and 30) (not shown) provided in the injection inner pipe 40. And crimping to the inner peripheral surface 1i (see FIG. 2) of the injection tube 1. Therefore, the injection material discharged from the injection material discharge port 32h does not leak from the region E sandwiched between the packers 30 and 30, and is injected into the region below the packer 30 below the injection tube 1. It is possible to prevent the material from entering and the injection material from entering the region above the upper packer 30 of the injection tube 1.
The region E sandwiched between the packers 30 and 30 is filled with an injection material (injection chemical solution) discharged from the injection material discharge hole 32h of the injection inner tube 40, and a ground-side injection material supply system (for example, injection material) (not shown) The injection pressure is applied by a pump for use.

1 and 4, the injection material in the region E is formed from two rows of through holes 1h formed in the vicinity of the center of the injection tube 1 in the axial direction (vertical direction in FIG. 1; a direction perpendicular to the paper surface in FIG. 4). The injection material is discharged.
In order to prevent complication of illustration, in FIG. 4, the injection material is discharged from only the four through holes 1 h of the injection tube 1, but actually, the injection material is discharged from all the through holes 1 h. .
The injection material discharged from the through-hole 1h is not clearly shown because the gap (the gap is very thin) formed between the outer peripheral surface 1o of the injection tube 1 and the inner peripheral surface 2i of the rubber mold 2 (elastic mold). ) (Flow indicated by arrow F1).

Then, as indicated by an arrow F2 in FIG. 4, the gap flows between the outer peripheral surface 1o of the injection tube 1 and the inner peripheral surface 2i of the rubber mold 2 in the circumferential direction.
In order to prevent the complication of illustration, an arrow F2 in FIG. 4 shows a state in which only the counterclockwise direction flows from the through hole 1h. However, it also flows clockwise.
In addition, the injection material flowing through the gap between the outer peripheral surface 1o of the injection tube 1 and the inner peripheral surface 2i of the rubber mold 2 is not only in the circumferential direction of the injection tube 1, but also as shown in FIG. Mainly flows in the longitudinal direction (vertical direction in FIG. 1), particularly in the direction toward the boundary B (see FIG. 3).

In FIG. 4, the injection material (arrow F <b> 2) flowing in the circumferential direction through the gap between the outer peripheral surface 1 o of the injection tube 1 and the inner peripheral surface 2 i of the rubber mold member 2 is the length of the pair of rubber mold members 2, 2. From the boundary in the direction (“boundary B” in FIGS. 1 and 3), it flows outward in the radial direction over the entire circumferential direction (arrow F3). Here, the boundary B in FIG. 1 means the boundary between the pair of elastic mold members 2 and 2 in FIG.
FIG. 4 shows an injection material (arrow F3) that has flowed radially outward from the longitudinal boundary (“boundary” B in FIG. 1) between the pair of rubber molds 2 and 2 over the entire circumferential direction. As described above, it flows in the longitudinal direction (vertical direction in FIG. 1) in the groove 2c (not shown in FIG. 1; see FIGS. 2 and 3) formed in the rubber mold 2.
In order to prevent the complication of illustration, in FIG. 4, an arrow F <b> 3 indicating the flow of the injecting material radially outwards along the boundary B (see FIGS. 1 and 3) of the rubber mold material 2 is indicated by the rubber mold material 2. It is shown only in a part of the cross section (four places in FIG. 4). However, as described above, the injection material actually flows outward in the radial direction over the entire circumferential direction of the cross section of the rubber mold 2.

For simplification of illustration, in FIG. 1 and FIG. 4, the flow of the injected material is not shown in the groove 2c, but as described above, outward in the radial direction over the entire circumferential direction of the boundary B. The poured injection material flows in the groove 2c and moves in the longitudinal direction (vertical direction in FIG. 1) over a wide range.
1 and 4, the injected material that has flowed in the longitudinal direction (vertical direction in FIG. 1) in the groove 2c (not shown in FIG. 1; see FIG. 2) is the outer peripheral surface 2o of the rubber mold 2 from the groove 2c. And the inner circumferential surface 3i of the heat-shrinkable tube 3 flow in the circumferential direction (arrow F4: see FIG. 4), and from the slit 3s formed at a predetermined position of the heat-shrinkable tube 3 into the ground G Injected (arrow F5).
In order to prevent complication of illustration, the arrow F4 in FIG. 4 is displayed only on a part between the outer peripheral surface 2o of the rubber mold 2 and the inner peripheral surface 3i of the heat-shrinkable tube 3. However, in reality, the injection material is also present in the region between the outer peripheral surface 2o of the rubber mold 2 and the inner peripheral surface 3i of the heat-shrinkable tube 3 except for the arrow F4 shown in FIG. Flowing.
In FIG. 4, since the injection pressure when the injection material is injected into the ground G from the slit 3 s acts, a crack C (crack) is formed in the solidified sealing material 20. Since the slits 3s are intermittently formed in the longitudinal direction (vertical direction in FIG. 1) at regular intervals, cracks C (cracks) are continuously formed in the solidified sealing material 20 in the vertical direction.

According to the illustrated first embodiment, the injection material (injection chemical solution) flows through the groove 2c and moves over a wide range in the longitudinal direction, so that the injection material is applied to the ground G over a wide range in the longitudinal direction. Injected. Thereby, the injection material can be injected into the ground over the entire injection material discharge section length Lj (FIG. 1).
In FIG. 1, in order to prevent the complication of illustration, a solid black arrow F5 indicating the flow of the injection material (in FIG. 1, the flow of the injection material going radially outward) Only two locations in the center of the direction are shown. However, in actuality, the injection material flows in the groove 2c, so that it moves to a wide range in the longitudinal direction and is discharged from the slit 3s (not shown in FIG. 1). And about the part shown with the white arrow IF5 currently displayed in multiple numbers by the longitudinal direction of FIG. 1, an injection material is discharged.
In other words, the white arrow IF5 represents the injection material discharged from the slit 3s and indicates that the injection material is discharged from the slit 3s provided in the heat-shrinkable tube 3.

In the heat-shrinkable tube 3, slits 3s (see FIG. 2) are formed at vertical positions corresponding to the white arrow IF5. As shown in FIG. 4, six slits 3s are formed in the circumferential direction, for example.
The slits 3s may be appropriately formed (axial pitch, number) at positions where cracks should be generated.

The injection pressure (flow of F5) of the injection material acts on the solidified sealing material 20 from the slit 3s.
When the injection pressure of the injection material acts, stress concentration occurs in the solidified sealing material 20, and cracks C are continuously formed in the vertical direction. The injection material flows in the crack C and reaches the ground to be injected.

In the illustrated first embodiment, the through-hole 1h of the injection tube 1 is formed at a plurality of locations (see FIG. 2). However, even if there is only one through-hole 1h, the injection material flows through the groove 2c and is injected. Injection is performed over the entire material discharge section length Lj (see FIG. 1).
Compared to the prior art in which the injection tube had to be perforated over the entire length of the injection material discharge section, in the illustrated first embodiment, the position of the through hole 1h is limited to the central portion of the injection tube 1. can do. Therefore, the man-hour of the process (drilling) that precedes the injection tube 1 with the through hole 1h can be greatly reduced.

And according to 1st Embodiment of illustration, even when the injection material discharge area length Lj is changed, it is not necessary to change the space | interval of the packers 30 and 30 in the injection | pouring inner pipe 40. FIG. This is because the injection material flows through the groove 2c formed on the outer periphery 2o of the rubber mold member 2 and is injected over the entire injection material discharge section length Lj.
Therefore, according to the illustrated first embodiment, even if the injection material discharge section length Lj is changed, it is not necessary to change the injection inner tube 40.
In the prior art, when the injection material discharge section length Lj is changed, the injection inner tube itself has to be changed by changing the interval between the packers of the injection inner tube. The injection material discharge section length Lj is changed in steps of 10 cm depending on the site. Therefore, in the prior art, many types of injection inner pipes are required.
On the other hand, in the present invention, it is not necessary to prepare various types of injection inner pipes 40, and the construction cost can be reduced accordingly.

In the illustrated first embodiment, for example, a rubber mold member 2 is used without using a member such as an R-plane. Since the rubber mold 2 is used, it is only necessary to create a “mold” of the mold, and a large number can be freely manufactured in a short time.
Moreover, it can act as a check valve by the elasticity of the rubber itself of the rubber mold member 2 (elastic force acting in the direction of tightening the vinyl chloride pipe). Here, the check valve is a check valve for the flow of the injection material flowing between the outer peripheral surface 1o of the injection tube 1 and the inner peripheral surface 2i of the rubber mold material 2, and the heat shrink tube 3 and the rubber mold material 2. It means both check valves for the flow of injectate between them.

Even if the injection material injected into the ground flows backward in the region between the heat shrinkable tube 3 and the rubber mold member 2, the region between the heat shrinkable tube 3 and the rubber mold member 2 is expanded. Therefore, it is difficult for the injection material to flow backward in the region between the heat-shrinkable tube 3 and the rubber mold material 2.
In addition, since the rubber mold 2 exerts an elastic force in the direction of tightening the injection tube 1, in order for the injection material to flow between the outer peripheral surface 1o of the injection tube 1 and the inner peripheral surface 2i of the rubber mold 2, It must face the elastic force. Therefore, it is difficult to reversely flow the outer peripheral surface 1o of the injection tube 1 and the inner peripheral surface 2i of the rubber mold 2.
Therefore, the injected material injected into the ground flows back through the region between the heat-shrinkable tube 3 and the rubber mold 2 and the region between the outer peripheral surface 1o of the injection tube 1 and the inner peripheral surface 2i of the rubber mold 2. Thus, it is extremely difficult to reach the through hole 1h drilled in the injection tube 1, and the injection material is prevented from flowing back into the injection tube 1.
Therefore, in the illustrated first embodiment, the backflow prevention performance of the injection material is improved as compared with the prior art.

In addition, since the rubber mold material 2 exerts an elastic force in the direction in which the injection tube 1 is tightened, even if the heat shrinkable tube 3 is covered, the relative position between the rubber mold material 2 and the injection tube 1 is shifted. Absent.
Therefore, the illustrated first embodiment has improved assemblability (reduction in assembly time and improvement in assembly accuracy) as compared with the prior art.

Here, since the rubber mold 2 exerts an elastic force in the direction in which the injection tube 1 is tightened, the rubber mold 2 and the injection tube 1 are in close contact with each other. However, the rubber mold 2 is elastic due to elasticity. The injection material that has flowed radially outward from the through-hole 1h drilled in the injection tube 1 flows between the outer peripheral surface 1o of the injection tube 1 and the inner peripheral surface 2i of the rubber mold 2 (in the longitudinal direction and the circumferential direction). When trying to (flow of F2), even if the pressure of the injection material is not high, the rubber mold member 2 expands (moves) radially outward.
Therefore, even if the pressure of the injection material is not high, the injection material can flow as shown by the arrow F2 (FIGS. 1 and 4).

  Similarly, even if the rubber mold 2 and the heat-shrinkable tube 3 are in close contact with each other, even if the pressure of the injection material is not high because the rubber mold material 2 is elastically deformed, the injection material is indicated by arrows F4 and F5 (FIG. 1 and flows as shown in FIG. 4) and reliably injected into the ground G.

Next, a second embodiment will be described with reference to FIGS. The ground injection device according to the second embodiment is generally indicated by reference numeral 10A.
FIG. 5 shows a cross-sectional shape of the ground injection device 10A according to the second embodiment, and FIG. 6 shows a state in which the rubber mold (elastic material) 2A, which is a component of the ground injection device 10A, is viewed obliquely. Yes.
In 1st Embodiment of FIGS. 1-4, the cross-sectional shape (outer shape) cut by the surface orthogonal to the axial direction of the rubber-made mold material 2 is circular.
On the other hand, in 2nd Embodiment of FIG. 5, FIG. 6, the cross-sectional shape (outer shape) cut by the surface orthogonal to the axial direction of 2A of rubber-made mold materials is a regular hexagon.

  In FIG. 5, a groove 2Ac having a rectangular cross section is formed over the entire length in the longitudinal direction along the axis center at the center of the six sides of the regular hexagon of the rubber mold 2A. Note that the cross-sectional shape of the hollow portion of the rubber mold 2A is circular as in the first embodiment.

Since the cross-sectional shape of the rubber mold 2A is a regular hexagon, the heat-shrinkable tube 3A having a cylindrical shape before heating also becomes a regular hexagon when heated and contracted after being covered with the rubber mold 2A. And the slit 3As is formed in the corner | angular part of the regular hexagon of the heat shrinkable tube 3A which became a regular hexagon by heat contraction.
By forming the slits 3As at the corners of the regular hexagon, stress concentration easily occurs in the sealing material due to the discharge pressure of the injection material, and cracks are easily formed.
Configurations and operational effects other than those described above in the second embodiment are the same as those in the first embodiment shown in FIGS.

In FIG. 7 illustrating the state of performing the ground injection method using the illustrated first and second embodiments, the injection target section Ls is set across the non-injection section Ln from the ground surface Gf. . In FIG. 7, since the vertical distance of the injection target section Ls is much longer than the longitudinal dimension (vertical dimension) of the ground injection devices 10 and 10A, a plurality of ground injection devices 10 (10A) are arranged in the vertical direction. It is connected. For example, in the construction example of FIG. 7, the same three ground injection devices 10 (10A) are connected, and in the construction example of FIG. 8, the same three ground injection devices 10 (10A) and the ground shorter than that The injection device 10B is connected.
At the time of injection, as shown by (1) to (3) in FIG. 8, each injection tube 10 (10A, 10B) is provided with an injection inner tube 40 provided with packers 30, 30 (in FIG. Insert only 30). The injection material is injected into the ground for each injection tube 10 (10A, 10B) in which the injection inner tube 40 (only the packers 30 and 30 are shown in FIG. 8) provided with the packers 30 and 30 is inserted. (Arrow F5).

Here, as shown in FIG. 8, the same injection inner tube 40 (only the packers 30 and 30 are shown in FIG. 8) also for the ground injection device 10 (10A) and the ground injection device 10B having different lengths in the longitudinal direction. Can be used.
In FIG. 8, the code | symbol BD has shown the area | region where the injection material was inject | poured.
The ground injection devices 10, 10A, and 10B are not limited to connecting three as shown in FIG. 7, but four or more if four can be connected as shown in FIG. May be connected. Alternatively, two or less ground injection devices 10, 10 </ b> A, and 10 </ b> B can be connected and used (including a case where only a single ground injection device 10, 10 </ b> A, and 10 </ b> B is used).

It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.
For example, in the illustrated embodiment, the cross-sectional shapes of the rubber mold members (elastic mold members) 2 and 2A are a circle and a regular hexagon, respectively, but may be other shapes such as a triangle to a dodecagon. Or an elliptical shape may be sufficient.
Note that the cross-sectional shape of the triangle to dodecagon does not necessarily have to be a regular triangle to a regular dodecagon. It may have a cross-sectional shape of an unequal side triangle to an unequal side dodecagon.

DESCRIPTION OF SYMBOLS 1 ... Injection pipe 2 ... Rubber mold material 3 ... Heat-shrinkable tube 10, 10A, 10B ... Ground injection apparatus 20 ... Area | region / construction area | region 30 with which sealing material is filled 30 ... Packer 40 ... Inner pipe

Claims (3)

An injection tube, an elastic type material covering the outer peripheral portion, with a heat-shrinkable member covering the outer periphery of the elastic type material, the injection tube is formed with a through-hole, a pair of elastic-type material injection tube Are fitted from both ends and cover the through-hole, and a groove extending in the longitudinal direction is formed in the outer peripheral portion of the pair of elastic mold members, and a slit is formed in the heat-shrinkable member. A ground injection device characterized by being made.   The ground injection device according to claim 1, wherein the slit formed in the heat-shrinkable member is formed at a position corresponding to a location where a crack is formed in the solidified sealing material. The ground injection device according to claim 1, wherein the slit formed in the heat-shrinkable member is formed intermittently in the longitudinal direction.

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