JP6990005B2 - Chemical injection method and equipment - Google Patents

Description

The present invention relates to an injection method for injecting an injection chemical solution (for example, cement milk) into the ground using an injection device.

In the injection method, a boring hole is excavated in the ground to be constructed and a chemical injection device is inserted.
As shown in FIG. 10, the drug solution injection device 100 includes an outer tube 11 and an injection inner tube 12, and a plurality of injection ports 11A are formed in the outer tube 11 at predetermined intervals in the longitudinal direction, and the outer tube 11 is formed in the longitudinal direction. An elastic member 11B having a function of a check valve is provided at each injection port forming position.
The outer pipe 11 is formed in a hollow tubular shape, and a chemical liquid injection pipe 12 (inner pipe with a packer) provided with a chemical liquid supply port 12A (discharge port) and a packer 12B is inserted into the hollow space of the outer pipe 11.

As shown by the dotted line (virtual line) in FIG. 10, when injecting the drug solution, the injection mechanism 12C is positioned in the region where the drug solution should be injected, and the inner tube 12 with a packer (the inner tube 12 with a packer) is located at the position corresponding to the injection port 11A of the outer tube 11. The chemical liquid supply port 12A of the chemical liquid injection pipe) is positioned, and the packer 12B is inflated. By expanding the packer 12B, the injected drug solution supplied from the drug solution supply port 12A to the hollow portion of the outer tube 11 is discharged only from the injection port 11A of the outer tube 11 in the region where the drug solution should be injected (arrow CP). When the chemical solution is discharged (arrow CP), the elastic member 11B (sleeve-shaped elastic member) having the function of a check valve is deformed from the state shown by the solid line to the state shown by the dotted line.
When the injection of the drug solution is completed, the packer 12B is contracted to pull up the inner tube 12 with the packer (move vertically upward), and the injection mechanism 12C is positioned in the next planned injection area (the area where the drug solution should be injected). Then, the packer 12B is inflated again in the next scheduled injection region to inject the drug solution. In this way, the drug solution is sequentially injected in the area where the drug solution should be injected.

However, since the elastic member 11B (sleeve-shaped elastic member) having the function of the check valve shown in FIG. 10 is used as a valve for preventing backflow, the thickness dimension (reference numeral δ) of the elastic member 11B is used. Only the outer tube 11 protrudes outward in the radial direction. In FIG. 10, the thickness dimension of the elastic member 11B is indicated by the reference numeral δ.
Since the elastic member 11B having the function of the check valve by the thickness dimension δ protrudes outward in the radial direction of the outer tube 11, as shown in FIG. 11, the function of the check valve is provided on the inner wall surface of the boring hole H. The lower end portion 11BE of the elastic member 11B having the elastic member 11B interferes with the boring hole H, which becomes a resistance when the chemical liquid injection device 100 is inserted into the boring hole H. In particular, as shown in FIG. 11, when the excavation device 13 is provided at the tip of the chemical solution injection device 100 and the chemical solution injection device 100 is inserted into the boring hole H while drilling the boring hole H, the boring hole H is formed. Since the inner diameter of H is equal to the outer diameter of the chemical liquid injection device 100, the resistance due to the lower end portion 11BE of the elastic member 11B having the function of the check valve interfering with the inner wall surface of the boring hole H becomes large. In FIG. 11, reference numeral 12 represents an inner tube with a packer (drug injection tube).
In addition, the lower end portion 11BE of the elastic member 11B may interfere with the inner wall surface of the boring hole H, so that the elastic member 11B having the function of a check valve may be worn or damaged and may not function as a valve. Also exists.

The applicant also has an outer tube and an inner tube for injection.
A groove extending in the circumferential direction is formed on the outer peripheral surface of the outer pipe.
Injection ports are formed in the groove at equal intervals in the circumferential direction.
Two annular elastic members (for example, O-rings) are fitted in the groove.
The radial inner region of the groove is composed of a curved surface.
We have previously proposed a chemical solution injection device in which the radial distance of the groove is set to a depth at which the annular elastic member fitted therein does not protrude from the outer peripheral surface of the outer tube (Japanese Patent Application No. 2016). -171665).
Subsequent studies have demonstrated that this drug infusion device is very effective in injecting grout solutions.
However, since a strong tensile force always acts on the annular elastic member (for example, O-ring), when injecting a grout material (for example, a cement suspension) in which particles are suspended, the grout is used. When the annular elastic member is slightly worn by the particles suspended in the material and a slight crack is generated, the strong tensile force acts on the crack and (the crack) rapidly develops, resulting in annular elasticity. There is a problem that the member breaks.

As another conventional technique, a technique capable of executing chemical injection even in a region directly under an existing structure has been proposed (see Patent Document 1).
However, the above-mentioned prior art (Patent Document 1) cannot solve various problems caused by the interference between the elastic member having the function of the check valve and the inner wall of the boring hole.

Japanese Unexamined Patent Publication No. 2014-125781

The present invention has been proposed in view of the above-mentioned problems of the prior art, and can reliably exhibit the function as a valve for injecting a chemical solution, does not interfere with the inner wall surface of the boring hole, and does not interfere with the inner wall surface of the boring hole for a long period of time. A chemical injection device that can function as a valve and does not damage the components of the valve even when injecting grout material in which particles are suspended, and such a device. It is intended to provide a method of injecting a drug solution using.

The chemical injection method of the present invention is (a drilling step of drilling a boring hole H).
An outer tube (1) and an injection inner tube (2) are provided, and a groove (1A) extending in the circumferential direction is formed on the outer peripheral surface (1D) of the outer tube (1), and the groove (1A) is formed. The injection ports (1B) are formed at equal intervals in the circumferential direction, and two hollow cylindrical elastic members (1C1 and 1C2) are fitted in the groove (1A) so as to be laminated in the radial direction. A step portion is not formed on the side surface of the groove (1A) (a wall surface extending in the radial direction of the outer tube 1 orthogonal to the bottom surface 1AA), and a hollow cylindrical elastic member arranged radially outward. (1C2) has an outer pipe (1) axial dimension larger than that of the hollow cylindrical elastic member (1C1) arranged inward in the radial direction, and the outer pipe (1) axial direction of the groove (1A) is set. The dimension (B) is set to be equal to the axial dimension of the outer tube (1) of the hollow cylindrical elastic member (1C2) arranged on the radial outer side of the laminated hollow cylindrical elastic member, and the dimension (B) is set to be equal to the axial dimension of the groove (1A). As for the depth (DH), when the injection liquid is not discharged (other than at the time of injection), the hollow cylindrical elastic member (1C1, 1C2) fitted in the groove (1A) is the outer peripheral surface of the outer tube (1). The depth is such that the outer tube (1) does not protrude outward from (1D) in the radial direction, and when the injection liquid is discharged, both ends in the axial direction of the hollow cylindrical elastic member (1C2) arranged on the outer side in the radial direction A chemical injection device (10) set to a depth at which a gap is formed between both ends of the outer tube (1) axially and the side surface of the groove (1A), which is rolled up outward in the radial direction (boring hole H). The process of arranging the chemical injection device (inside) and
The injection step includes an injection step of injecting a drug solution.
When the injected chemical solution is discharged (injected) from the injection port (1B) of the chemical solution injection device (10), the hollow cylindrical elastic member (1C1, 1C2) is deformed and the chemical solution is discharged outward in the radial direction. It is characterized by having a step of forming a flow path (s) (injected into the ground).

In the chemical solution injection method of the present invention, the chemical solution injection device (10) is provided with a drilling device (for example, a drilling bit, a high-pressure water injection mechanism, etc.) at the tip (tip in the drilling direction), and is used during the drilling step. It is preferable that the chemical injection device (10) is inserted into the boring hole (H) at the same time as the drilling of the boring hole (H), so that the drilling step and the chemical liquid injection device placement step can be executed at the same time. ..
Of course, the drilling step is executed by a drilling device prepared separately from the chemical injection device (10), and after the boring hole (H) is drilled in the drilling step, the chemical solution injection device (10) is used. The chemical liquid injection device arrangement step may be executed by inserting it into the boring hole (H). In this case, the drilling step and the chemical solution injection device placement step are not executed at the same time, and the chemical solution injection device placement step is executed after the drilling step.

Further, the chemical solution injection device (10) of the present invention is
Equipped with an outer tube (1) and an injection inner tube (2),
A groove (1A) extending in the circumferential direction is formed on the outer peripheral surface (1D) of the outer pipe (1).
Injection ports (1B) are formed in the groove (1A) at equal intervals in the circumferential direction.
Two hollow cylindrical elastic members (1C1 and 1C2) are fitted in the groove (1A) so as to be laminated in the radial direction.
No step portion is formed on the side surface of the groove (1A), and the step portion is not formed.
The hollow cylindrical elastic member (1C2) arranged radially outward has a larger outer tube (1) axial dimension than the hollow cylindrical elastic member (1C1) arranged radially inward.
The outer tube (1) axial dimension (B) of the groove (1A) is the outer tube (1) axis of the hollow cylindrical elastic member (1C2) arranged radially outside the laminated hollow cylindrical elastic member. Set equal to the directional dimension,
The depth (DH) of the groove (1A) is determined by the hollow cylindrical elastic member (1C1, 1C2) fitted in the groove (1A) when the injection liquid is not discharged (other than at the time of injection). A hollow cylindrical elastic member (1C2) having a depth that does not protrude outward from the outer tube (1) outer peripheral surface (1D) in the radial direction and is arranged radially outside when the injection liquid is discharged. ) Is rolled up outward in the radial direction, and the depth is set to the depth at which a gap is formed between both ends in the axial direction and the side surface of the groove (1A). It is characterized by being done.

According to the present invention having the above-mentioned configuration, a groove (1A) is formed in the outer tube (1) outer peripheral surface (1D) of the chemical solution injection device (10), and the injection port (1B) is formed in the groove (1A). And two hollow cylindrical elastic members (1C1, 1C2: for example, rubber ring) are fitted, so that the injection port (1B) formed in the groove (1A) is in a state where the injection work is not performed. ) Is closed by two hollow cylindrical elastic members (1C1, 1C2).
When injecting the chemical solution into the ground, when the packer (2A) is inflated and the chemical solution is discharged from the injection inner tube (2), the discharge pressure of the chemical solution (P1: chemical solution injection pressure) acts on the two. The hollow cylindrical elastic member (1C1, 1C2) is deformed to form a gap with the groove (1A), and the gap becomes a flow path (s) for the injection drug solution.
Then, the injected chemical solution is discharged outward in the radial direction (injected into the ground) through the gap (flow path s).

When the injection (discharge) of the chemical solution is completed, the discharge pressure (P1) of the injected chemical solution acting on the hollow cylindrical elastic member (1C1, 1C2) disappears, so that the elasticity of the hollow cylindrical elastic member (1C1, 1C2) disappears. The repulsive force acts to return the hollow cylindrical elastic member (1C1, 1C2) to the state before the injection chemical discharge pressure (P1) acts, and close the discharge port (1B).
In other words, according to the present invention, the chemical liquid injection flow path (s) is opened only at the time of injection, as in the case of a valve composed of an elastic member (sleeve-shaped elastic member) having a function of a conventional check valve. However, when not injecting, the drug solution injection flow path (s) is closed.

Further, according to the present invention, the injection chemical solution is, for example, a suspension in which cement particles are suspended, and the hollow cylindrical elastic member (1C1, 1C2) is worn by the cement particles when the injection chemical solution is injected into the ground. In addition, the elastic repulsive force (T) at the axial center of the hollow cylindrical elastic member (1C2) located outward in the radial direction is applied to the worn portion of the hollow cylindrical elastic member (1C1) located inward in the radial direction. It acts inward in the radial direction, and the elastic repulsive force (T) of the elastic member (1C1) itself also acts on the central portion in the axial direction of the hollow cylindrical elastic member (1C1) located inward in the radial direction. Therefore, even if the inner side of the hollow cylindrical elastic member (1C1) is worn in the radial direction, the worn portion is crushed by the elastic repulsive force (T) at the central portion in the axial direction of the hollow cylindrical elastic member (1C1, 1C2). Therefore, a flow path through which the chemical liquid leaks is not formed between the hollow cylindrical elastic member (1C1) and the groove (1A). That is, at the time of non-injection, the state in which the hollow cylindrical elastic member (1C1) located inward in the radial direction is in close contact with and closed with the injection port (1B) of the injection liquid passage is always maintained.
Therefore, the present invention can be carried out even if the injectable drug solution is a suspension.

Further, according to the present invention, since the elastic repulsive force of the elastic member always acts inward in the radial direction on the hollow cylindrical elastic member (1C1, 1C2), the hollow cylindrical elastic member inward in the radial direction is elastic. Even if an attempt is made to maintain the deformed state in which both ends of the member (1C1) in the axial direction are rolled up outward in the radial direction, the other hollow cylindrical elastic member (1C2) located on the outer side in the radial direction is located in the central region in the axial direction. Due to the acting elastic repulsive force (T), both ends in the axial direction of the hollow cylindrical elastic member (1C1) inward in the radial direction cannot be maintained in a deformed state so as to be rolled up in the outward direction in the radial direction. It is pressed inward in the radial direction of (1A).
Therefore, the injection liquid is not discharged from the injection liquid passage, and even if the injection liquid flows backward from the ground side, the hollow cylindrical elastic member (1C1) inward in the radial direction is the radius of the groove (1A). It is completely sealed where it is pressed inward in the direction and is in close contact.

In addition, the hollow cylindrical elastic members (1C1, 1C2) are fitted in the groove (1A), and the radial distance (DH: groove depth) of the groove (1A) is fitted therein. Since the hollow cylindrical elastic member (1C1, 1C2) is set to a depth that does not protrude from the outer peripheral surface (1D) of the outer tube (1), the chemical liquid injection device (10) is placed in the boring hole (H). Upon insertion, the hollow cylindrical elastic member (1C1, 1C2) does not interfere with the inner wall surface of the boring hole (H) and does not act as a resistance to movement in the boring hole (H) of the chemical injection device (10). ..
Therefore, the hollow cylindrical elastic member (1C1, 1C2) is not worn or damaged by the friction caused by the interference between the hollow cylindrical elastic member (1C1, 1C2) and the inner wall surface of the boring hole (H), and the hollow cylindrical shape is formed. The elastic members (1C1, 1C2) can surely exert the function as a valve for a long period of time.

It is explanatory drawing which shows the embodiment of this invention. It is a partially enlarged cross-sectional view which shows the cross section of the part indicated by reference numeral A in FIG. FIG. 3 is a partially enlarged cross-sectional view illustrating the operation in the embodiment. FIG. 3 is a partially enlarged cross-sectional view showing an unsuitable configuration. It is explanatory drawing of the reason why the structure shown in FIG. 4 is inconvenient. It is a partially enlarged sectional view which is unsuitable structure and shows the structure different from the structure of FIG. It is explanatory drawing of various dimensions in FIG. It is an end view which shows the position of an inlet. It is a partially enlarged sectional view which shows the valve used in the chemical solution injection method which concerns on another Embodiment of this invention. FIG. 3 is a partial cross-sectional view showing a main part of a chemical injection device having a valve made of an elastic member having a function of a conventional check valve. It is explanatory drawing which shows the problem of the prior art of FIG.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 9.
FIG. 1 shows an outline of an embodiment of the present invention, in which a groove 1A extending in the circumferential direction is formed on the outer peripheral surface 1D of the outer tube 1 of the chemical solution injection device 10.
The outer tube 1 is configured as a hollow tubular having a hollow space, and the hollow space is provided with an injection inner tube 2 (indicated by a dotted line in FIG. 1). The injection inner tube 2 includes a packer 2A, and the configuration and operation / effect of the injection inner tube 2 are the same as those of the conventionally known inner tube 12 with a packer described with reference to FIG.
The grooves 1A of the outer tube 1 are formed at a plurality of locations where the chemical solution should be injected in the axial direction of the outer tube 1 (vertical direction in FIG. 1) (in FIG. 1, only one groove 1A in the axial direction is shown. ). Here, the plurality of places where the chemical solution should be injected are the locations where the chemical solution injection port is provided, which will be described later with reference to FIG. The injection inner tube 2 moves in the hollow space in the outer tube 1 and is held at a predetermined position corresponding to the plurality of locations where the chemical solution should be injected.
In FIGS. 1 to 7, for example, four chemical solution injection ports 1B are formed in the groove 1A at equal intervals in the circumferential direction. However, in FIG. 1, the injection port 1B at the center in the radial direction (left-right direction) is displayed, but the injection ports 1B at both ends in the radial direction indicate only the position by the sign and the leader line.

In FIG. 2, the bottom surface 1AA of the groove 1A having the width direction (vertical direction in FIG. 2) dimension B is processed flat, and the injection port 1B is formed in the center of the groove 1A in the width direction (vertical direction in FIG. 2). There is.
Two hollow cylindrical elastic members 1C1 and 1C2 (rubber bands) made of elastic materials (for example, rubber) are fitted in the groove 1A so as to be laminated in the radial direction so as to close the injection port 1B. There is.
The rubber band 1C1 is arranged so as to close the chemical liquid injection port 1B, which is a radial outlet of the injection liquid passage. The rubber band 1C2 is arranged on the outer side in the radial direction (right side in FIG. 2) of the rubber band 1C1, and the rubber band 1C1 is suppressed inward in the radial direction by its elastic repulsive force (arrow T in FIG. 3).
As shown in FIG. 2, the depth DH (radial distance) of the groove 1A is such that when the rubber bands 1C1 and 1C2 are fitted into the groove 1A, the rubber bands 1C1 and 1C2 protrude from the outer peripheral surface 1D of the outer tube 1. It is set to a depth that does not.
Various dimensions of the groove 1A and the rubber bands 1C1 and 1C2 will be described later with reference to FIG. 7.

In FIG. 3, in a state where the chemical solution injection operation is not performed, the rubber bands 1C1 and 1C2 (hollow cylindrical elastic members) are housed in the groove 1A in the state shown by the solid line. The injection port 1B formed on the bottom surface 1AA of the groove 1A is closed by the rubber band 1C1 shown by the solid line.
In the state where the chemical solution injection operation is not performed in FIG. 3, the radial end portion (left end portion in FIG. 5) of the rubber band 1C2 does not protrude from the outer peripheral surface 1D of the outer tube 1.

When the chemical solution is discharged from the injection inner tube with a packer (not shown), the rubber bands 1C1 and 1C2 are deformed as shown by the dotted line (rolled outward in the radial direction) due to the discharge pressure P1 (chemical solution injection pressure) of the chemical solution, and the groove 1A. A gap is formed between the wall surface and the wall surface, and the chemical solution flows through the gap. In FIG. 3, the streamlines of the chemical solution flowing through the gap are indicated by a plurality of arrows s. In other words, the chemical solution is jetted (discharged) outward in the radial direction (left side in FIG. 3) along the flow paths indicated by the plurality of arrows s, and is injected into the ground.
Here, the elastic repulsive force (arrow T in FIG. 3) of the rubber (elastic member) as a material always acts on the rubber bands 1C1 and 1C2 inward in the radial direction. When the injection (discharge) of the chemical solution is completed, the discharge pressure P1 of the chemical solution acting on the rubber bands 1C1 and 1C2 disappears. , The deformed state (rolled up state) shown by the dotted line in FIG. 3 is restored to the state shown by the solid line. Then, the rubber band 1C1 closes the injection port 1B (discharge port) again, and the rubber bands 1C1 and 1C2 return to the state of being housed in the groove 1A.
As a result, according to the illustrated embodiment, the chemical solution injection flow indicated by the arrow s only when the chemical solution is injected, as in the case of a valve composed of an elastic member (sleeve-shaped elastic member) having the function of a conventional check valve. When the path is opened and the drug solution is not injected, the drug solution injection flow path indicated by the arrow s is closed.

Here, the injection chemical solution is, for example, a suspension in which cement particles are suspended, and even if the rubber bands 1C1 and 1C2 are worn by the cement particles when the injection chemical solution is injected into the ground, the rubber band 1C1 is worn at the worn portion. The elastic repulsive force T at the axial center portion of the rubber band 1C2 acts inward in the radial direction (left in FIGS. 2 and 3), and the elastic repulsive force T of the rubber band 1C1 itself also acts. Therefore, even if the inside of the rubber band 1C1 in the radial direction is worn, the worn portion is crushed by the elastic repulsive force T at the axial center portion of the rubber band 1C2 and the elastic repulsive force T of the rubber band 1C1 itself, and the groove 1A Since it is in close contact with the bottom surface 1AA of the rubber band 1C1, a flow path through which the chemical solution leaks is not formed between the rubber band 1C1 and the bottom surface 1AA of the groove 1A. That is, when the chemical solution is not injected (during non-injection), the state in which the rubber band 1C1 is in close contact with the groove 1A and the injection port 1B of the injection solution passage is closed is always maintained.
Therefore, even if the injectable drug solution is a suspension, it can be satisfactorily carried out in the illustrated embodiment.

4 and 5 show an example unsuitable for the embodiment of the present invention, in which only one rubber band 1CS (hollow cylindrical elastic member) is fitted in the groove 1E of the outer tube 1. .. Hereinafter, the reason why the structure shown in FIG. 4 is inconvenient will be described.
In the embodiments of FIGS. 1 to 3, as shown in detail in FIGS. 2 and 3, two rubber bands 1C1 and 1C2 are housed in the groove 1A, and are radially outward from the injection port 1B of the groove 1A. When the chemical discharge pressure P1 (chemical liquid injection pressure) acts on the two rubber bands 1C1 and 1C2, the two rubber bands 1C1 and 1C2 are deformed so as to roll up outward in the radial direction to form a gap between the two rubber bands 1C1 and the wall surface of the groove 1A. Consists of the flow path indicated by the arrow s (see FIG. 3).
Even with the configuration of FIG. 4, a single rubber band 1CS arranged so as to close the chemical solution injection port 1B at the time of chemical solution injection is provided at both ends in the axial direction of the single rubber band 1CS due to the chemical solution discharge pressure P1. In FIG. 4, both ends in the vertical direction are deformed so as to be rolled up outward in the radial direction (to the right in FIG. 4) (in FIG. 4, both upper and lower ends of the rubber band 1CS are deformed from the positions shown by solid lines to those shown by dotted lines). , The flow path s4 is configured between the groove 1E and the wall surface. In FIG. 4, reference numerals 2 and 2C indicate a chemical solution injection tube and a chemical solution injection mechanism, respectively. Further, in FIG. 4, the display of the single rubber band 1CS, the flow path s4, and the like on the other side in the radial direction (left side in FIG. 4) is omitted.

However, in the configuration of FIG. 4, a single rubber band 1CS is deformed, and both ends in the axial direction (both ends in the vertical direction in FIG. 4) are rolled up outward in the radial direction (to the right in FIG. 4). In the case of (the state shown by the dotted line in FIG. 4), even if the injection of the chemical solution is completed and the discharge pressure P1 of the injected chemical solution disappears, the state shown by the solid line in FIG. 4 cannot be restored due to deterioration or hardening of the rubber band 1CS, for example. There is a possibility.
Using the chemical injection device shown in FIG. 4, reference numeral No. 5 in FIG. After injecting the drug solution at the position No. 1, No. 1 is used. In the case of injecting the chemical solution at the position of 2, reference numeral No. 2. When the rubber band 1CS of No. 1 remains in the state of the dotted line in FIG. 4 due to aged deterioration or curing, the reference numeral No. 1 is used. After the injection of the chemical solution in No. 1 is completed, the reference numeral No. 1 is used. When the chemical solution injection is started by applying the injection chemical solution discharge pressure P1 at the two points, the reference numeral No. A part of the chemical solution discharged from No. 2 has a reference numeral No. 2 via, for example, the path RO. There is a risk that the rubber band 1CS at location 1 will pass through the location where it is deformed and rolled up (the state indicated by the dotted line in FIG. 4) and invade (backflow) into the injection inner tube 2 of the drug solution injection device 10. be.
The display of the single rubber band 1CS and the path RO of the chemical solution intrusion (backflow) on the left side of FIG. 5 is omitted.

In the illustrated embodiment with respect to the examples of FIGS. 4 and 5, as shown in FIG. 3, the two rubber bands 1C1 and 1C2 always have an elastic repulsive force acting inward in the radial direction. Even if both ends of the rubber band 1C1 in the axial direction (vertical direction in FIG. 3) are to be kept deformed so as to be rolled up in the radial direction outward (right side in FIG. 3), the other rubber located on the outer side in the radial direction. Due to the elastic repulsive force T acting on the central region of the band 1C2 in the axial direction (vertical direction in FIG. 3), both ends of the rubber band 1C1 in the axial direction (vertical direction in FIG. 3) are radially outward (right in FIG. 3). It is not possible to maintain the deformed state so that it rolls up, but it is pressed inward in the radial direction of the groove 1A and comes into close contact with the bottom surface 1AA.
Therefore, the injection liquid is not discharged from the injection liquid passage, and even if the injection liquid flows backward from the ground side, the rubber band 1C1 is completely pressed inward in the radial direction of the groove 1A. Is sealed to.

Even if both ends of the rubber band 1C2 located in the radial direction (right side in FIG. 3) are rolled up in the radial direction (right side in FIG. 3) in the axial direction (vertical direction in FIG. 3). It is the elastic repulsive force in the axial center region of the rubber band 1C2 that presses the rubber band 1C1 inward in the radial direction of the groove 1A, and even if both ends of the rubber band 1C2 in the axial direction are deformed, the rubber band 1C1 is pressed into the groove 1A. The action of pressing inward in the radial direction of is unchanged.

FIG. 6 is also an inappropriate example as an embodiment of the present invention, and shows another example from FIG. In FIG. 6, another groove F2 is formed in the center of the groove F1 in the axial direction (vertical direction in FIG. 6), and the groove F2 has two O-rings 1o and 1o (annular elastic members). A single rubber band 1CS (hollow cylindrical elastic member) is fitted in the groove F1.
Similar to the configuration shown in FIG. 4, in the example of FIG. 6, the chemical discharge pressure (drug injection pressure) acts from the injection port 1B (via the two deformed O-rings 1o) at the time of chemical injection, and a single chemical solution is injected. When both ends of the rubber band 1CS in the axial direction (vertical direction in FIG. 6) are deformed so as to be rolled up and the deformation is maintained due to aging deterioration, hardening, etc., the chemical solution is injected into the chemical solution as shown in FIG. There is a risk of invading (backflow) into the injection inner tube 2 (see FIG. 1) of 10.
Further, when a suspension in which particles such as cement are suspended is used as the injection liquid, the O-rings 1o and 1o are worn and cracks are generated, and the O-rings 1o and 1o themselves are cracked in the cracks. The elastic repulsive force acts to advance and break.
Further, in addition to the groove F1 (depth dimension D1), it is necessary to machine the groove F2 (depth dimension D2), and the outer pipe 1 (see FIG. 1) is formed (in the radial direction) only by the radial dimension “D1 + D2”. Since it must be cut, there is a problem that the strength of the outer pipe 1 is lowered.
The embodiments of FIGS. 1 to 3 do not cause the above-mentioned problems in the example of FIG.

Next, with reference to FIG. 7, the dimensions of the groove 1A and the rubber bands 1C1 and 1C2 (hollow cylindrical elastic member) shown in FIGS. 2 and 3 will be described.
Assuming that the axial dimension of the rubber band 1C1 (vertical dimension in FIG. 7) is L1 (length L1 = axial length of 1C1), the length L11, the diameter φ of the injection liquid passage leading to the injection port 1B, and the reference numeral. The relationship with the distance indicated by Rα can be expressed by the following equation.
L1 = Rα × 2 + φ,
∴Rα = (L1-φ) / 2
Here, the distance Rα corresponds to the length of the flow path of the injection liquid (the whole is indicated by the reference numeral s) formed between the rubber band 1C1 and the groove 1A.
On the other hand, the distance Rβ is equal to the thickness t2 of the rubber band 1C2. That is, Rβ = t2. Further, the distance Rβ corresponds to the length of the flow path of the injection liquid formed between the rubber band 1C2 and the groove 1A.

As described above, the distance Rα and the distance Rβ form a part of the flow path s of the injection liquid formed between the rubber bands 1C1 and 1C2 and the groove 1A, and the flow path resistance is increased in the flow path s. It's a big part.
Therefore, when setting the chemical solution injection device according to the illustrated embodiment, the flow path resistance of the flow path s, particularly the distance Rα and the distance Rβ, is such that the injection chemical solution (grout material) is injected by a pump having a normal discharge pressure within a predetermined time. Set as much as possible. Based on this, the axial length L1 of the rubber band 1C1, the diameter φ of the injection liquid passage, and the thickness t2 of the rubber band 1C2 are determined.
In other words, the distance Rα and the distance Rβ (that is, the axial length L1 of the rubber band 1C1, the diameter φ of the injection liquid passage, the thickness t2 of the rubber band 1C2) depend on the construction conditions, the pump discharge pressure used, and the like. , Determined on a case-by-case basis.

In FIG. 7, the axial length L2 (vertical length in FIG. 7) of the rubber band 1C2 is substantially equal to the axial length of the groove 1A.
In the embodiment, the elastic repulsive force of the rubber band 1C2 is suppressed so that the state in which both ends of the rubber band 1C1 in the axial direction (vertical direction in FIG. 7) are rolled up is not maintained when the chemical solution is injected. The elastic repulsive force of the rubber band 1C2 is determined based on the axial length L2 of the rubber band 1C2 and the thickness t2 of the rubber band 1C2. In determining the axial length L2 of the rubber band 1C2, the ratio of the rubber band 1C1 to the length L1 has a great influence.
When setting the chemical solution injection device in the illustrated embodiment, regarding the axial length L2 of the rubber band 1C2 and the thickness t2 of the rubber band 1C2, as described above, the rubber band 1C1 is due to the elastic repulsive force of the rubber band 1C2. It is set so that both ends of the rubber band can be suppressed.

Here, the construction conditions of the injection method, which is considered to be "general", are, for example,
The flow rate Q of the infusion solution is Q = 20 liters / minute,
The diameter φ of the injection liquid passage is φ = 7 mm,
Pump discharge pressure Pe is 0.2MPa ≤ Pe ≤ 0.5MPa
If so, each dimensional value in FIG. 7 is, for example,
t1 = 1mm,
t2 = 2mm,
L1 = 30 mm (Lα = 10 mm),
L2 = 50mm
Is.
However, according to the inventor's experiment, the fluctuation of ± 20% was acceptable for the above t1, t2, L1 and L2.

With reference to FIG. 8, the circumferential position of the injection port 1B in the outer tube 1 will be described.
8 (A) is the case of the embodiment described with reference to FIGS. 1 to 7, and the injection ports 1B are provided at four points in the circumferential direction at equal intervals. In FIG. 8, the groove 1A formed in the outer tube 1 is not shown.
The number of inlets 1B is not limited to four in the circumferential direction, and as shown in FIGS. 8 (B) and 8 (C), the injection port 1B is provided at three locations in the circumferential direction and two in the circumferential direction. It can also be provided at equal intervals at each location.
Although not shown, it is possible to form only one injection port 1B in the circumferential direction, and it is also possible to form five or more injection ports 1B in the circumferential direction.

When constructing the illustrated embodiment, first, a drilling step of drilling a boring hole H (see FIG. 11 showing the prior art) is performed by a conventionally known method.
Next, the chemical solution injection device 10 according to the embodiment of the present invention described with reference to FIGS. 1 to 7 is arranged in the drilled borehole H.
Then, the injection step of injecting the chemical solution into the ground from the chemical solution injection device 10 is executed. In the injection step, the drug solution is discharged after the packer of the injection inner tube 2 with a packer (FIG. 1) is expanded, and the injection drug solution is discharged (injected) from the injection port 1B of the drug solution injection device 10. When injecting a chemical solution, the rubber bands 1C1 and 1C2 (hollow cylindrical elastic member) are deformed by the discharge pressure P1 (chemical solution injection pressure), and the chemical solution is discharged outward in the radial direction (injected into the ground). The flow path s is formed.

In the chemical solution injection step, if the grooves 1A are formed at a plurality of locations in the outer tube 1 to be injected with the chemical solution, the injection inner tube 2 is sequentially moved according to the positions of the injection ports 1B of the plurality of grooves 1A. While arranging, the chemical injection into the ground is performed, for example, from the lower region to the upper region.
However, if an injection inner tube having a plurality of injection nozzles and a plurality of packers is used corresponding to the positions of the plurality of grooves 1A (injection ports 1B) in the outer tube 1, the ground can be simultaneously reached from the injection ports 1B of the plurality of grooves 1A. It is also possible to inject a chemical solution into it.

In the illustrated embodiment, if a drilling device (for example, a drilling bit, a high-pressure water injection mechanism, etc., reference numeral 13 in FIG. 11 showing the prior art) is installed at the tip (tip in the drilling direction) of the chemical injection device 10, the above. Since the chemical injection device 10 is arranged in the boring hole H at the same time as the drilling of the boring hole H at the time of drilling the boring hole H, the drilling of the boring hole H and the arrangement (insertion) of the chemical liquid injection device are performed at the same time. Can be executed.
Of course, the boring hole H may be drilled by a drilling device prepared separately from the chemical liquid injection device 10, and after the boring hole H is drilled, the chemical liquid injection device 10 may be inserted into the boring hole H. In this case, the drilling of the boring hole H and the insertion (arrangement) of the chemical liquid injection device 10 into the boring hole H are not executed at the same time, and the chemical liquid injection device 10 is inserted after the drilling of the boring hole H (the chemical liquid injection device 10 is inserted (arranged). Placed).

According to the illustrated embodiment, the chemical liquid injection flow path s is configured only at the time of injection, and the chemical liquid injection flow path is formed at the time of non-injection, as in the prior art using a valve composed of an elastic member having a check valve function. s is not configured.
Here, in the illustrated embodiment, the rubber bands 1C1 and 1C2 are fitted in the groove 1A, and the radial distance (DH: groove depth, see FIG. 2) of the groove 1A is fitted therein. Since the rubber bands 1C1 and 1C2 are set to a depth that does not protrude from the outer peripheral surface 1D of the outer tube 1, when the chemical liquid injection device 10 is inserted into the boring hole H, the rubber bands 1C1 and 1C2 are formed in the boring hole H. It does not interfere with the inner wall surface and does not act as a resistance to movement in the boring hole H of the chemical injection device 10.
Therefore, the rubber bands 1C1 and 1C2 are not worn or damaged by the friction caused by the interference between the rubber bands 1C1 and 1C2 and the inner wall surface of the boring hole H, and the rubber bands 1C1 and 1C2 function as valves for a long period of time. It can be surely demonstrated.

Since the two rubber bands 1C1 and 1C2 always have an elastic repulsive force inward in the radial direction, both ends of the rubber band 1C1 located inward in the radial direction are outward in the radial direction. Even if it is deformed so as to be rolled up, both ends in the axial direction of the rubber band 1C1 are rolled up outward due to the elastic repulsive force T acting on the axially central region of the other rubber band 1C2 located on the outer side in the radial direction. It is pressed inward in the radial direction of the groove 1A without being deformed in the same manner.
Therefore, the injection liquid is not discharged from the injection liquid passage, and even if the injection liquid flows backward from the ground side, the rubber band 1C1 is completely pressed inward in the radial direction of the groove 1A. Is sealed to.
In addition, in the embodiment shown in FIGS. 1 to 7, the injection liquid is, for example, a suspension in which cement particles are suspended, and the rubber bands 1C1 and 1C2 are the cement particles when the injection liquid is injected into the ground. Since the worn part of the rubber band 1C1 located inward in the radial direction is crushed inward in the radial direction by the elastic repulsive force T of the rubber band 1C2, the rubber band 1C1 and the groove 1A are in close contact with each other. A flow path through which the chemical liquid leaks is not formed. Therefore, the state in which the rubber band 1C1 closes the injection port 1B of the injection liquid passage during non-injection is always maintained. That is, even if the injectable drug solution is a suspension, it can be satisfactorily carried out in the illustrated embodiment.

In the chemical solution injection method according to the embodiment different from the above-described embodiments of FIGS. 1 to 7, two rubber bands 1C1 and 1C2 (hollow cylindrical elastic members) are fitted into the groove 1A of the outer pipe 1. Instead, as shown in FIG. 9, two O-rings 1o1 are fitted in the curved groove 1G in the outer tube 1.
That is, in the bottom surface 1GA of the groove 1G, two O-rings 1o1 which are annular elastic members made of an elastic material (for example, rubber) are closed so as to close the central injection port 1B in the width direction (vertical direction in FIG. 9). It is fitted. At that time, the two O-rings 1o1 are evenly arranged in the width direction of the groove 1G, and the central axis 1BC of the injection port 1B defines the boundary between the two O-rings 1o1.
As shown in FIG. 9, the depth DH (radial distance) of the groove 1G is set to a depth at which the O-ring 1o1 does not protrude from the outer peripheral surface 1D of the outer tube 1 when the O-ring 1o1 is fitted into the groove 1G. Will be done.
Here, in FIG. 9, the bottom surface 1GA of the groove 1G formed on the outer peripheral surface 1D of the outer tube 1 is formed on a curved surface having a predetermined radius of curvature.

When the discharge pressure of the chemical solution is received from the injection port 1B at the time of injecting the chemical solution, the two O-rings 1o1 are properly deformed, a chemical solution flow path is formed between the two O-rings 1o1, and the chemical solution is the outer tube 1. Is discharged outward in the radial direction (injected into the ground).
Other configurations and operational effects in the embodiment using the valve shown in FIG. 9 are the same as those in the embodiments shown in FIGS. 1 to 7.

It should be added that the illustrated embodiment is merely an example and is not a description to the effect of limiting the technical scope of the present invention.
For example, as the annular elastic member, a rubber O-ring is exemplified in the embodiment, but other materials may be used, and the cross-sectional shape of the annular elastic member may not be circular.

1 ... Outer tube 1A ... Groove 1B ... Injection port 1C1, 1C2 ... Rubber band (hollow cylindrical elastic member)
1D ... Outer peripheral surface 2 ... Injection inner tube 10 ... Chemical injection device H ... Boring hole s ... Flow path

Claims (2)

An outer tube (1) and an injection inner tube (2) are provided, and a groove (1A) extending in the circumferential direction is formed on the outer peripheral surface (1D) of the outer tube (1), and the groove (1A) is formed. The injection ports (1B) are formed at equal intervals in the circumferential direction, and two hollow cylindrical elastic members (1C1 and 1C2) are fitted in the groove (1A) so as to be laminated in the radial direction. No step is formed on the side surface of the groove (1A), and the hollow cylindrical elastic member (1C2) arranged radially outward is the hollow cylindrical elastic member (1C1) arranged radially inward. The outer pipe (1) axial dimension is set larger than that of), and the outer pipe (1) axial dimension (B) of the groove (1A) is located on the radial outer side of the laminated hollow cylindrical elastic member. The depth (DH) of the groove (1A) is set to be equal to the axial dimension of the outer tube (1) of the arranged hollow cylindrical elastic member (1C2), and the depth (DH) of the groove (1A) is the groove (1A) when the injection liquid is not discharged. ), The hollow cylindrical elastic member (1C1, 1C2) has a depth that does not protrude outward from the outer tube (1) outer peripheral surface (1D) in the radial direction, and the injection drug solution is discharged. When this is done, both ends in the radial direction of the hollow cylindrical elastic member (1C2) arranged on the outer side in the radial direction are rolled up outward in the radial direction, and the outer tube (1) both ends in the axial direction and the side surface of the groove (1A). A chemical injection device placement step for arranging the chemical injection device (10) set to a depth at which a gap is formed, and a chemical solution injection device placement step.
The injection step includes an injection step of injecting a drug solution.
When the injected chemical solution is discharged from the injection port (1B) of the chemical solution injection device (10), the hollow cylindrical elastic member (1C1, 1C2) is deformed and the chemical solution is discharged outward in the radial direction. A chemical injection method characterized by having a step of forming s). Equipped with an outer tube and an inner tube for injection,
A groove extending in the circumferential direction is formed on the outer peripheral surface of the outer pipe.
Injection ports are formed in the groove at equal intervals in the circumferential direction.
Two hollow cylindrical elastic members are fitted in the groove so as to be laminated in the radial direction.
No step portion is formed on the side surface of the groove (1A), and the step portion is not formed.
The hollow cylindrical elastic member (1C2) arranged radially outward has a larger outer tube (1) axial dimension than the hollow cylindrical elastic member (1C1) arranged radially inward.
The outer tube (1) axial dimension (B) of the groove (1A) is the outer tube (1) axis of the hollow cylindrical elastic member (1C2) arranged radially outside the laminated hollow cylindrical elastic member. Set equal to the directional dimension,
The depth (DH) of the groove (1A) is a hollow cylindrical elastic member (1C1, 1C2) fitted in the groove (1A) except when the injection liquid is not discharged (other than injection). Is a depth that does not protrude outward from the outer tube (1) outer peripheral surface (1D) in the radial direction, and is a hollow cylindrical elastic member arranged radially outside when the injection liquid is discharged. 1C2) is characterized in that both ends in the axial direction are rolled up outward in the radial direction and the depth is set so that a gap is formed between both ends in the axial direction of the outer tube (1) and the side surface of the groove (1A). Chemical injection device.

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