JP5485810B2 - Injection method and equipment - Google Patents

Description

  The present invention relates to an injection method for injecting a grout material into a ground (including a rock) to lower the water permeability of the ground or increase the strength of the ground, and an apparatus used therefor.

  The injection method consists of drilling the target ground with a boring machine, boring rod, injection pipe, bit, etc., then inserting the injection pipe into the drilled hole and pumping the grout material with a pump etc. A grout material is injected into the target ground from the tip, and the water permeability of the target ground is reduced and the strength is increased by hardening of the grout material injected into the target ground.

  The injection tube may be inserted into the drilled hole at the same time as the drilling. However, depending on the target ground or the method of injection, the injection tube may be placed in a post-processed hole in a later step.

  In general, in the injection method, it is one of the important issues to sufficiently seal the periphery of the injection tube, that is, the gap between the boring hole and the injection tube. If this is insufficient, most of the grout material coming out from the tip of the injection pipe leaks to the ground through the periphery of the injection pipe without entering the target ground.

  The above-mentioned problem is dealt with by using a section packer in the injection method mainly for rock. That is, the section packer installed in the drilled borehole is inflated by a method such as compressed air, high-pressure gas, or mechanical tightening so as to adhere to the hole wall for injection.

  According to this method, the occurrence of the above phenomenon can be prevented by blocking the gap between the borehole and the injection tube with the injection packer, but the mechanism is complicated and expensive, and when the borehole wall collapses, the section packer is It may not be applicable depending on site conditions, such as installation may not be possible. FIG. 11 shows an example of use of the air packer 25 as an injection packer used in an injection method for a rock mass.

  The air packer 25 includes a packer rubber 24 and an air supply pipe 26 for sending compressed air or high-pressure gas to the packer rubber 24. The packer rubber 24 is inflated by compressed air or high-pressure gas and is brought into close contact with the hole wall. The grout material 27 is poured out from the tip of the injection tube to which the packer rubber 24 is attached.

Among the injection methods for reducing the permeability and increasing the strength of soft ground, there are a double pipe double packer method and a double pipe double phase strainer method. For example, Patent Document 1 below discloses a double pipe double packer method, and Patent Document 2 below discloses a double pipe double phase strainer method.
JP-A-8-311855 JP-A-6-212620

  In the double pipe double packer method, as shown in FIG. 12, a boring hole is drilled to an improved depth using a casing 28, and an injection pipe (outer pipe, sleeve pipe) 29 with a valve is inserted into the casing 28. A sealing material (cement bentonite) 30 is filled around the injection pipe 29 with a valve, the sealing material 30 is cured by pulling out the casing 28, and then an injection pipe (inner pipe) 31 with a double packer is connected to the injection pipe 29 with a valve. The grout material 34 is injected into each injection valve 32 by being inserted therein.

  On the other hand, the double-pipe double-phase strainer method is a method of injecting two types of grouting materials into the ground by using a double pipe. The grouting material is prevented from leaking to the ground surface, and osmotic injection with a slow-binding chemical solution 36 is performed as secondary injection. FIG. 13 shows a double-pipe multi-phase strainer method.

  In the double pipe double packer method, the sealing material seals the gap between the boring hole and the outer pipe, and the injection packer having the same mechanism as that used in the injection method for the rock is used for the outer pipe and the inner pipe. By sealing the gap between the pipes, it is possible to prevent the grout material from leaking to the ground surface, but the process is complicated and diverse, and the cost is high.

  The double-pipe double-phase strainer method is superior in that the gap between the boring hole and the outer pipe can be filled with fewer work procedures than the double-pipe double packer method, but the operation to use multiple grout materials is different. It is complicated and the planned amount cannot be injected depending on the target ground, and the planned effect may not be obtained.

  The object of the present invention is to eliminate the inconvenience of the conventional example, and even when the injection is for the ground where the hole wall collapses, the grout material is difficult to leak from the periphery of the injection tube to the ground surface, An object of the present invention is to provide an injection method and apparatus that can arbitrarily determine the length of the section, have fewer work procedures, and reduce costs.

  In order to achieve the above object, the present invention according to claim 1 is a hollow injection in which a plurality of slits are formed on the outer peripheral surface at appropriate intervals in the circumferential direction, and the slits are formed at intervals in the vertical direction. An inner pipe for injection having a packer part is inserted into the outer pipe, and the slit as an injection point of the injection outer pipe is pressed from the inside by the packer part to open the slit as a discharge port. By pressing the upper slit from the inside with the packer part, the outer pipe is expanded to form the outer pipe packer, and the grout material is injected from the tip of the inner pipe for injection into the target ground through the discharge port. This is the gist.

  According to the first aspect of the present invention, since the outer tube packer is formed by pressing the slit formed in the outer peripheral surface of the hollow injection outer tube from the inside and expanding the diameter, the structure is simple, the work procedure is small, the hole Leakage from the gap between the wall and the periphery of the outer injection tube can be prevented.

  The outlet of the grout material presses and opens the slit as the injection point from the inside, so that the slit is kept closed until the injection starts, so that foreign matter can be prevented from entering the inside of the injection outer tube, and the hole wall Even in a ground that collapses, the discharge port can be reliably opened by pressing from the inside of the outer injection tube.

  Furthermore, since the outer tube packer portion and the discharge port can be set arbitrarily, the depth and section length per injection can also be set arbitrarily.

  The present invention according to claim 2 is characterized in that the portion forming the outer tube packer is hermetically sealed with a rubber or the like rich in elasticity.

  According to the second aspect of the present invention, the portion forming the outer tube packer seals the slit with rubber or the like rich in elasticity, so that the outer periphery of the outer tube packer formed by expanding the diameter by pressing from the inside Since the surface is made of rubber or the like rich in elasticity, it is possible to reliably prevent leakage from the gap between the hole wall and the periphery of the outer injection pipe even in the ground where the hole wall collapses.

  As described above, the present invention prevents the grout material from leaking to the ground surface through the periphery of the injection outer tube by blocking the gap between the boring hole and the injection outer tube with the outer tube packer. Further, by adjusting the positions of the outer tube packer and the discharge port, it is possible to easily match the section length per injection suitable for improving the target ground uniformly. Furthermore, since the outer tube packer and the discharge port can be easily formed only by the process of expanding the injection outer tube from the inside, there are few work procedures.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the injection device of the present invention will be described. As shown in FIG. 1, the injection device includes an injection outer tube 1, an inner tube 7 for boring, and an inner tube 8 for injection with a packer.

  The injection outer tube 1 shown in FIG. 1 is made of metal, but is not limited to metal, for example, synthetic resin, as long as it is rich in plastic deformation and is rigid enough to prevent damage even when drilled by an entrainment type. It is not limited to raw materials such as made of glass or glass fiber.

  A plurality of slits 2 having a length of, for example, about several centimeters to several meters and a width of several millimeters or less are provided in parallel in the circumferential direction on the outer peripheral side surface of the injection outer tube 1 depending on the field conditions, used tools, and the like.

  Further, a plurality of slits 2 arranged in parallel in the circumferential direction are formed at intervals in the vertical direction of the outer injection tube 1 to form a plurality of stages.

  The width of the slit 2 is preferably set to several millimeters or less as described above so as to be closed to the pressure from the inside of the subsequent process and not to leak, and to be opened and formed as a discharge hole after the pressure.

  Furthermore, the number of the slits 2 arranged in parallel can be determined as appropriate so that the injection outer tube 1 can be expanded in diameter by being pressed from the inside, and the grout material can be injected into the ground as a discharge hole by opening.

  By the way, when the injection pipe is installed inside the ground, a general method is to insert a casing having an inner diameter larger than the outer diameter of the injection pipe at the time of boring to hold the hole wall, and after drilling is completed. The injection pipe is inserted into the casing, and then the casing is pulled out for injection.

  Even in the present invention, it is possible to adopt this general method as a method of installing the injection outer tube 1, but problems such as an increase in the number of steps and collapse of the hole wall when the casing is pulled out are expected.

  Therefore, it was decided to be able to adopt an injection outer tube entrainment method during drilling. As a drilling method, a known method can be adopted, but an example will be described with reference to FIGS. The injection outer tube 1 and the boring inner tube 7 are integrated with each other, and also serves as excavation when the injection outer tube 1 is raised.

  As shown in FIG. 3, a tip shoe 4 having a ring bit 3 fitted to the tip of the injection outer tube 1 is screwed.

  The inner pipe 7 for boring is made by screwing the inner bit 5 to the tip of the boring rod 6, and the inner bit 5 can be accommodated in the ring bit 3.

  Therefore, the convex part 3a was formed in the ring bit 3, and the recessed part 5a with which this convex part 3a engages was formed in the peripheral surface part of the inner bit 5 as a thing of a collar structure.

  As shown in FIG. 3, the tip shoe 4 fitted with the ring bit 3 is first screwed into the tip of the injection outer tube 1, and then the boring rod 6 screwed with the inner bit 5 is inserted into the injection outer tube 1. Insert inside.

  Here, the concave portion 5a is formed on the peripheral surface portion of the inner bit 5, and the convex portion 3a is formed on the inner peripheral surface of the ring bit 3 at a position corresponding to the concave portion 5a of the inner bit 5, so that the boring rod 6 Is inserted into the outer tube 1, the side Yi of the inner bit 5 tip surface hits the convex portion 3 a on the inner peripheral surface of the ring bit 3 and cannot be inserted any more.

  Therefore, when the inner bit 5 is rotated until the convex portion 3a on the inner peripheral surface of the ring bit 3 reaches the side Xi (side of the concave portion 5a) of the inner end surface of the inner bit 5, the concave portion 5a on the peripheral surface portion of the inner bit 5 is obtained. The projection 3 a on the inner peripheral surface of the ring bit 3 is fitted to the inner end of the ring bit 3, and the inner bit 5 can be inserted until the front end surface projects forward from the front end of the ring bit 3.

  After inserting the boring rod 6 into the injection outer tube 1, the rotational force, propulsive force, etc. of a drilling machine (not shown) to which the boring rod 6 is joined are transmitted to the inner bit 5 at the tip of the boring rod 6, Drill the ground to be.

  At this time, by drilling while rotating the inner bit 5 in a direction in which the side Ao of the convex portion 3a on the inner peripheral surface of the ring bit 3 is in contact with the side Ai of the concave portion 5a on the peripheral surface portion of the inner bit 5, the ring The fitting of the convex portion 3 a on the inner peripheral surface of the bit 3 and the concave portion 5 a on the peripheral surface portion of the inner bit 5 is maintained, and the ring bit 3 is not detached from the inner bit 5.

  After the drilling of the target range is completed in this way, the boring rod 6 is pulled out in order to insert the inner pipe 8 for injection. As described above, the convex portion 3a on the inner peripheral surface of the ring bit 3 and the inner bit 5 Since the concave portion 5a of the peripheral surface portion is fitted, the boring rod 6 cannot be pulled out as it is.

  Therefore, first, the inner bit 5 is rotated in the opposite direction to the time of drilling. At this time, by slightly pushing the inner bit 5, the side Co of the convex portion 3 a on the inner peripheral surface of the ring bit 3 becomes the peripheral surface portion of the inner bit 5. The concave portion 5a moves along the side Ci, and the reverse rotation of the ring bit 3 causes the side Fo of the convex portion 3a on the inner peripheral surface of the ring bit 3 to abut on the side Fi of the concave portion 5a on the peripheral surface portion of the inner bit 3. It becomes possible.

  In this manner, the boring rod 6 and the inner bit 5 are collected after the drilling is completed, and the injection inner tube 8 with the packer portion 9 is inserted into the injection outer tube 1 instead.

  As shown in FIG. 6, the boring rod 6 is inserted into the inside of the outer injection tube 1 for excavation. As shown in FIG. 7, after the drilling is completed, the inner tube 8 for injection with the packer portion 9 is inserted into the outer tube. It is inserted until it reaches the slit portion G1 that matches the injection start location.

  As shown in the upper diagram of FIG. 2, the injection inner tube 8 with the packer portion 9 has a hollow injection tube 11 at the tip of the discharge port 12 and a packer portion 9 provided slightly above. The packer unit 9 can use an existing one, and expands it by applying fluid pressure such as air pressure, hydraulic pressure, water pressure or the like. In the figure, reference numeral 10 denotes the fluid pressure hose.

  The injection inner tube 8 with the packer portion 9 is inserted into the injection outer tube 1 and the packer portion 9 is expanded to expand the diameter of the injection outer tube 1 from the inside as shown in the lower diagram of FIG. The slit 2 of the tube 1 can be opened.

  When the packer portion 9 is enlarged as described above, as shown in the right diagram of FIG. 7, the slit portion G1 at the injection start location of the injection outer tube 1 is pressed from the inside to increase the diameter, and the slit 2 opens. .

  If the slit portion G1 at the injection start location of the injection outer tube 1 has sufficiently expanded, the packer portion 9 is reduced, and the inner tube 8 for injection with the packer portion 9 is inserted into the slit immediately above the injection start location. Pull up to part 2 G2.

  And the slit part of the injection | pouring outer tube | pipe 1 is expanded so that the grout material may not leak through the clearance gap between a hole wall and the injection | pouring outer tube | pipe 1 again by expanding the packer part 9 and expanding the slit part G2 of the injection | pouring outer tube | pipe 1. G2 is sufficiently expanded to complete this process.

  Next, the grout material is pumped to the injection inner tube 8 from the discharge port 12 at the tip of the injection inner tube 8 with the packer portion 9.

  Thus, since the inner tube 8 for injection with the packer portion 9 is hollow and the distal end portion is opened as the discharge port 12, the grout material pumped from an unillustrated injection device passes through the inside of the inner tube for injection. The grouting material is fed into the inside of the injection outer tube 1 from the opening.

  At this time, the slit part G1 suitable for the injection start location is opened, and the inside of the injection outer tube 1 of the slit part G2 directly above is blocked by the enlarged packer part 9, so that the grout material is the slit part G1. It is injected into the target ground through the opening.

  Further, since the diameter of the slit portion G2 is increased so that the grout material does not leak through the gap between the hole wall and the outer injection tube 1, the grout material is reliably injected into the target ground.

  After completion of the injection into the slit part G1, the packer part expanding inside the slit part G2 is reduced, and the inner tube for injection with packer is moved to the next injection part. In FIG. 7, injection is performed from the slit portion G2 next to the slit portion G1, and since the slit portion G2 has already sufficiently expanded in diameter, the packer portion is moved to the inside of the slit portion G3 to be expanded. Thereafter, the grout material is injected into the target range by repeating the above-described injection operation, and the operation is completed.

  FIG. 8 shows a second embodiment of the present invention. A packer rubber 14 is wound around the surface of the slit 2 of the injection outer tube 1 of the present invention in a cylindrical shape, and both ends thereof are caulked, and the packer portion of the injection outer tube 1 is shown. 15 is formed.

  This packer rubber 14 uses rubber or the like rich in elasticity as a material, expands following the deformation of the injection outer tube 1 and adheres to the gap with the hole wall on the outer peripheral surface of the injection outer tube 1, and the grout material is Leakage from the gap between the hole wall and the outer injection tube through the slit 2 and the traffic inside and outside the injection outer tube are prevented.

  In FIG. 8A, the packer rubber is not installed in the slit 2 serving as the outlet for grout material, but the packer rubber 14 is installed only in the slit serving as the packer portion 15 of the outer injection tube 1.

  In FIG. 8B, the backflow prevention cover 16 is attached to the slit for the discharge port. This backflow prevention cover 16 is such that it easily breaks and opens due to the expansion of the diameter of the injection outer tube 1 due to the expansion of the packer portion 9 of the injection inner tube 8 with the packer portion 9 described above in the first embodiment. As the material, a material having low strength and poor plastic deformability (a material that easily breaks when deformed), for example, hard plastic or non-woven fabric is used.

  Although the method of installing the outer injection pipe of the second embodiment of the present invention thus manufactured on the target ground and injecting the grout material is the same as that of the first embodiment, the description is avoided, but the second embodiment Since the injection outer tube 1 is provided with the packer portion 15 of the injection outer tube in which the packer rubber 14 is wound in a cylindrical shape, for example, as shown in FIGS. 9 and 10, the packer portion 15 of the injection outer tube 1 is previously provided. It is also possible to expand all the diameters and sequentially feed the grout material to the injection site as a separate process.

  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.

It is a front view of this invention apparatus used with the injection method of this invention. It is an image figure with which the injection | pouring outer tube was expanded and the slit was opened by expansion | swelling of the packer part of the injection | pouring inner tube with a packer part of the apparatus of this invention used by the injection | pouring method of this invention. It is a vertical side view which shows the engagement state of the ring bit of this invention apparatus, and an inner bit. It is a perspective view of the ring bit of the device of the present invention. It is a perspective view of the inner bit of the device of the present invention. It is explanatory drawing which shows the drilling condition of the injection method of this invention. It is explanatory drawing which shows the injection | pouring condition of the injection method of this invention. It is a front view of the injection outer tube used in the second embodiment of the injection method of the present invention. It is explanatory drawing of the front | former stage process which shows 2nd Embodiment of the injection method of this invention. It is explanatory drawing of the back | latter stage process which shows 2nd Embodiment of the injection method of this invention. It is explanatory drawing which shows the structure of an air packer. It is process drawing of a double pipe double packer construction method. It is process drawing of a double pipe double phase type strainer construction method.

1 Injection outer tube 2 Slit 3 Ring bit 3a Convex part
4 Tip shoe 5 Inner bit 5a Recess 6 Boring rod
7 Inner pipe for boring 8 Inner pipe 9 for injection 10 Packer part 10 Hose for packer 11 Hollow injection pipe 12 Discharge port 14 Packer rubber 15 Packer part 16 Backflow prevention cover

Claims (3)

  A plurality of slits are formed on the outer peripheral surface at appropriate intervals in the circumferential direction, and an injection inner tube having a packer portion is inserted into a hollow injection outer tube formed with the slits spaced apart in the vertical direction, The slit as the injection location of the outer injection tube is pressed from the inside by the packer portion to open the slit, and the discharge port is formed by pressing the upper slit of the discharge port from the inside by the packer portion. An injection method characterized in that a pipe is expanded to form an outer pipe packer, and a grout material is injected from the tip of the inner pipe for injection through the discharge port into the target ground.   2. The injection method according to claim 1, wherein the outer tube packer is formed by sealing the outer periphery of the slit with rubber having a high elasticity.   It is an apparatus used for the injection method of claim 1, a hollow injection outer tube in which a plurality of slits are formed on the outer peripheral surface at appropriate intervals in the circumferential direction, and the slits are formed at intervals in the vertical direction; . An injection device comprising an injection inner tube with a packer portion that pumps grout material from the tip into the injection outer tube.

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