JP2011017160A - Injection pipe structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection pipe structure which enables a worker to inject a grout into the ground having collected injection pipes uniformly.SOLUTION: This injection pipe structure is composed of an outer injection pipe 1 buried into the ground and an inner injection pipe 2 provided in the outer injection pipe 1. The outer injection pipe 1 is composed of an outer injection pipe body 1a, a water permeable mat material 5 provided at the outer periphery of the outer injection pipe 1a, and a film 3 provided on the outer periphery of the water permeable mat material 5. A plurality of grout discharge ports 1b are formed on the outer injection pipe body 1a. Grout discharge slits 3a are formed at positions being different from the grout discharge ports 1b in a filter 3 to open simultaneously with the boosting of the injection pressure of the grout to be discharged into the water permeable mat material 5.

Description

  The present invention relates to a structure of an injection tube used in a ground improvement method by an injection method, and can uniformly inject an injection material from an injection material discharge slit provided in the injection tube and infiltrate and inject it uniformly into the ground.

  The injection method in the ground improvement method is a method to improve the ground by injecting cement-based solidifying material or water glass-based chemicals through the injection pipe installed in the ground, mainly improving the water-stopping property of the ground, It is carried out for the purpose of increasing the strength and filling the cavity. As one of the injection methods, a double packer method is known.

  The injection tube in this case includes, for example, an injection outer tube 1 installed in the ground, and an injection inner tube 2 installed in the injection outer tube 1 as shown in FIGS. In particular, the outer injection tube 1 is composed of an injection outer tube main body 1a and a film 3 such as a rubber seal installed on the outer periphery thereof.

  The injection outer tube main body 1a is formed with a plurality of injection material discharge ports 1b, and the film 3 is formed with a plurality of injection material discharge slits 3a at positions different from the injection material discharge ports 1b. In addition, packers 4 and 4 are attached to the tip of the injection inner tube 2 on both upper and lower sides of the injection material discharge port 2a and the injection material discharge port 2a.

  The film 3 covers a certain range (one stage) where the injection material discharge port 1b of the injection outer tube main body 1a is formed, and prevents the injection material in the ground from flowing back into the injection tube from the injection material discharge port 1b. It works.

  The packers 4 and 4 serve to prevent the injected material discharged into the injection outer tube 1 from being moved up and down in the injection outer tube 1 when the injection material is injected.

  In such a configuration, when the packers 4 and 4 are expanded to seal the upper and lower ends of the injection material discharge port 2a between the injection outer tube 1 and the injection inner tube 2, and the injection material is pumped into the injection inner tube 2, The injected material is discharged between the packers 4 and 4 in the outer injection tube 1 from the injected material discharge port 2a.

  From there, it is injected into the surrounding ground through the injection material discharge port 1a of the outer injection tube 1, and further through the injection material discharge slit 3a of the film 3. At that time, by changing the injection stage by moving the injection inner tube 2 up and down in the injection outer tube 1, optimal injection can be performed for each stage according to the properties of the formation.

JP 09-143976 A JP 09-143777 A Japanese Patent Laid-Open No. 09-111747

  However, in the injection tube structure as described above, an injection material flow path through which the injection material flows between the injection outer tube main body 1a and the film 3 is not particularly provided. The injection material discharged between the injection outer tube main body 1a and the film 3 is injected into the ground only from the slit 3a near the injection material discharge port 1b. For this reason, it has been extremely difficult to uniformly improve the entire ground by allowing the injection material to uniformly penetrate the entire ground.

  In addition, when the amount of injection material discharged is increased, the injection pressure increases, so that not only does the infiltration injection occur in a split injection state, but uniform injection cannot be performed, and there is a problem that the injection material is wasted and the cost is increased. there were.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an injection tube structure that can uniformly inject an injection material into the ground around the injection tube.

  The injection tube structure according to claim 1 is an injection tube structure comprising an injection outer tube installed in the ground and an injection inner tube installed in the injection outer tube. The injection outer tube includes an injection outer tube body and an injection outer tube. It is composed of a water permeable mat material installed on the outer periphery of the main body and a film installed on the outer periphery of the water permeable mat material, and a plurality of injection material discharge ports in the injection outer tube main body are different from the injection material discharge ports of the film. Each is provided with an injection material discharge slit.

  The present invention is such that the injection material is uniformly discharged from the injection material discharge slit provided in the film so that the injection material is uniformly permeated into the ground around the injection tube. For example, the injection material discharged to the water-permeable mat material rises to a predetermined injection pressure in the water-permeable mat material and is injected into the ground from each injection material discharge slit. Can be injected.

  That is, the injection material can be uniformly discharged over the entire area of the injection outer tube body covered with the water-permeable mat material, and the injection speed per stage as a whole, although the injection speed per discharge port is small. Can be increased.

  In addition, the water-permeable mat material installed on the inside of the film allows low-pressure osmotic injection even if the injection pressure is increased to increase the discharge amount of the injection material. The injection length of one stage that was 0.3 to 0.5 m can be increased to about 1 to 2 m, which is twice or more, so that the injection of the injection material can be performed extremely efficiently and economically. .

  The injection tube structure according to claim 2 is the injection tube structure according to claim 1, wherein the injection material discharge slit opens with an increase in injection pressure of the injection material discharged into the water-permeable mat material, and the injection material It is formed so as to be closed when injection is completed.

  According to the present invention, the injection material discharged into the water-permeable mat material is filled in the entire water-permeable mat material, and the injection pressure in the water-permeable mat material rises to a predetermined pressure, so that the injection material discharge slit By opening, the injection material can be uniformly discharged from all the injection material discharge slits, and thus the injection material can be uniformly permeated into the surrounding ground.

  In addition, since the injection material discharge slit opens simultaneously with the end of the injection, the inflow of the injection material from the adjacent injection tube can be prevented. In addition, it is possible to prevent the injection material from flowing even when the injection is injected into the upper or lower part of the same injection tube.

  In addition, when the injection outer tube is installed in the ground by standing in the drilled hole, or when the sealing material is filled around the injection outer tube set in the drilled hole, earth and sand are discharged from the injection material. It is possible to prevent entry into the injection tube through the slit. In this case, if the film is formed of an elastic material such as rubber, the function as described above can be imparted to the injection material discharge slit.

  The injection tube structure according to claim 3 is the injection tube structure according to claim 1 or 2, wherein the injection material discharge slit is formed long in the longitudinal direction or the circumferential direction of the injection outer tube main body, and the length of each slit is It is characterized by being different.

  In the injection outer tube main body covered with a film, the injection form (shape) of the injection material can be changed by changing the aperture ratio of the injection material discharge slit. The aperture ratio of the injection material discharge slit can be freely changed by appropriately setting the length of each injection material discharge slit.

  For example, as shown in FIG. 2 (a), if the lengths of the injection material discharge slits are all the same, the discharge amount of the injection material is all uniform, so that the ground around the injection tube is improved to a columnar shape. be able to.

  Further, as shown in FIG. 2B, when the length of the injection material discharge slit is the longest at the center portion of the stage and gradually shortened upward and downward from the center portion, the discharge amount of the injection material becomes the stage. Since it is the most at the center and gradually decreases upward and downward from the center, the ground around the injection tube can be improved to a spherical shape. Further, as shown in FIGS. 3A and 3B, the injection material discharge slit may be formed long in the circumferential direction of the tube body.

  According to the present invention, the injection material discharged to the water-permeable mat material is injected into the ground from each injection material discharge slit due to an increase in injection pressure in the water-permeable mat material. It has the effect of being able to infiltrate uniformly.

  In addition, the permeable mat material installed on the inner side of the film allows osmotic injection even if the injection pressure is increased to increase the discharge amount of the injection material. Therefore, the injection length of the injection material can be increased very efficiently and economically.

1 shows an embodiment of an injection tube structure of the present invention, in which (a) is a partial longitudinal sectional view thereof, and (b) is a sectional view taken along the line II in (a). An arrangement example of injection material discharge slits provided long in the axial direction of the tube main body in the film is shown, (a) is a partial front view of an injection outer tube in which injection material discharge slits of the same length are provided at predetermined intervals, (B) is a partial front view of an injection outer tube in which injection material discharge slits having different lengths are provided at predetermined intervals. An arrangement example of injection material discharge slits provided long in the circumferential direction of the tube body in the film is shown, (a) is a partial front view of an injection outer tube in which injection material discharge slits of the same length are provided at predetermined intervals, (B) is a partial front view of an injection outer tube in which injection material discharge slits having different lengths are provided at predetermined intervals. An example of the conventional injection | pouring pipe | tube structure is shown, (a) is the one part longitudinal cross-sectional view, (b) is a roll line | wire sectional view in (a).

  1A and 1B show an embodiment of the present invention. In the figure, an injection outer tube 1 is installed in the ground, and an injection inner tube 2 is installed in the injection outer tube 1. The injection outer tube 1 includes an injection outer tube main body 1a, a water-permeable mat member 5 installed on the outer periphery of the injection outer tube main body 1a, and a film 3 installed on the outer periphery of the water-permeable mat member 5.

  The outer injection pipe body 1a has a plurality of injection material discharge ports 1b on the outer peripheral portion, and is formed of, for example, a perforated PVC pipe or a perforated steel pipe. The water-permeable mat member 5 holds the injection material discharged from the injection material discharge port 1b between the injection outer tube main body 1a and the film 3, and also in the injection material in the vertical direction and the circumferential direction of the injection outer tube main body 1a. It functions to impart a smooth flow, and is formed of a highly permeable material such as woven fabric, non-woven fabric, geonit, geonet, geogrid, or a composite product thereof.

  The film 3 has a plurality of injection material discharge slits 3a that are long in the tube axis direction or the circumferential direction of the injection outer tube main body 1a, and is made of, for example, rubber or polyethylene.

  The injection inner tube 2 is substantially the same as the conventional example described in FIGS. 4A and 4B, and the injection material discharge port 2a and the injection material discharge port 2a are sandwiched between the tips of the injection inner tube 2. Packers 4 and 4 are provided on both upper and lower sides.

  In such a configuration, the packers 4 and 4 of the injection inner tube 2 are expanded to seal both the upper and lower sides of the injection material discharge port 2 a between the injection outer tube 1 and the injection inner tube 2, and the injection material is injected into the injection inner tube 2. , The injection material is discharged from the injection material discharge port 2a between the packers 4 and 4 in the injection outer tube 1 and from there through the injection material discharge port 1b of the injection outer tube 1 into the permeable mat material 5. Discharged. And it inject | pours in the surrounding ground from the water-permeable mat material 5 through each injection material discharge slit 3a of the film 3 further.

  At that time, the injection material is held between the injection outer tube main body 1a and the film 3 by the water-permeable mat member 5, and a space is secured so that the injection material flows in the circumferential direction and the vertical direction of the injection outer tube main body 1a. Therefore, the injection material in the water-permeable mat member 5 can be uniformly permeated into the surrounding ground through the injection material discharge slit 3a from the entire length of the stage.

  Further, by changing the injection stage by moving the injection inner tube 2 up and down in the injection outer tube 1, it is possible to perform optimal injection according to the properties of the formation in each stage.

  2A and 2B show another embodiment of the present invention. In the injection outer tube main body 1a covered with the film 3, the opening ratio of the injection material discharge slit 3a is changed to change the injection material. The injection form (shape) can be changed. The aperture ratio of the injection material discharge slit 3a can be freely changed by appropriately setting the length of each injection material discharge slit 3a.

  For example, as shown in FIG. 2 (a), if the lengths of the injection material discharge slits 3a are all the same, since the discharge amount of the injection material is all uniform, the ground around the injection tube is improved to a columnar shape. can do.

  Further, as shown in FIG. 2B, when the length of the injection material discharge slit 3a is the longest at the center of the stage and gradually shortened upward and downward from the center, the injection amount of the injection is Since it is the largest at the center of the stage and gradually decreases upward and downward from the central part, the ground around the injection tube can be improved to a spherical shape.

  FIGS. 3A and 3B show the injection material discharge slit 3a formed long in the circumferential direction of the pipe body.

  According to the present invention, the injection material can be uniformly permeated and injected into the ground around the injection tube.

DESCRIPTION OF SYMBOLS 1 Injection outer tube 1a Injection outer tube main body 1b Injection material discharge port 2 Injection inner tube 2a Injection material discharge port 3 Film 3a Injection material discharge slit 4 Packer 5 Water-permeable mat material

Claims (3)

  In an injection tube structure comprising an injection outer tube installed in the ground and an injection inner tube installed in the injection outer tube, the injection outer tube is a water permeable mat installed on the outer periphery of the injection outer tube main body and the injection outer tube main body. And a film installed on the outer periphery of the water-permeable mat material, the injection outer tube main body is provided with a plurality of injection material discharge ports, and an injection material discharge slit is provided at a position different from the injection material discharge port of the film. An injection tube structure characterized by comprising:   The injection material discharge slit is formed so as to open as the injection pressure of the injection material discharged into the water-permeable mat material increases, and to close when the injection of the injection material is completed. The injection tube structure according to Item 1.   The injection tube structure according to claim 1 or 2, wherein the injection material discharge slit is formed long in a major axis direction or a circumferential direction of the injection outer tube main body, and each slit has a different length.

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