JP2008169546A - Injection pipe and grouting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection pipe which dispenses with the repetition, for example, of the operation step of stepping up the injection pipe in each conventional injection step, by preventing the leakage of a chemical agent onto ground, when a fluid is injected into ground to be improved, and which can drastically shorten a construction time for fluid injection by enabling the fluid to be efficiently injected into the ground-to-be-improved in a short period of time in such a manner that the fluid is ejected in a planar state in all the directions of an outer periphery from any one of ejection ports, even if the plurality of ejection ports are arranged at arbitrary intervals in the longitudinal direction of the injection pipe, and a grouting method using the injection pipe. <P>SOLUTION: In this injection pipe, a first annular slit ejection port 5, which communicates with an outer-pipe channel and which is constituted without the use of an annular elastic body, and a plurality of second annular slit ejection ports 6, 6, 6, 6 and 6, which communicate with an inner-pipe channel and which are constituted without the use of an annular elastic body, are arranged at arbitrary longitudinal intervals on the outer peripheral surface of an outer pipe. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an injection pipe that can be used for ground improvement and soil improvement, and a grout injection method using the injection pipe.

  In Japan, there are many soft grounds with poor ground conditions, so there are many cases where construction work must be carried out even on soft grounds. In recent years, sandy ground liquefaction has been particularly important as a seismic measure. Prevention measures are regarded as important. In addition, the earthquake resistance standards were revised following the 1995 Great Hanshin-Awaji Earthquake, and measures to liquefy directly under and near existing structures are also urgent issues.

  As measures against liquefaction, for example, a. Sand compaction pile method, vibrating rod method, weight drop compaction method, etc. that increase the density of sand ground by compaction, b. Deep-mixing treatment method, quick lime pile method, injection solidification method, which is solidified by cement, chemicals, etc., c. A method for replacing crushed stone with another material that does not liquefy, d. Examples include a gravel drain construction method and various drain construction methods for dissipating the generated pore water pressure.

  Here, the injection solidification method is optimal as a countermeasure for liquefaction under construction conditions in which a large construction machine such as directly under or near an existing structure or in a place where there is a sky head restriction cannot be used.

  The agent (grouting agent) used in the injection solidification method is required to have a property of easily penetrating into the gaps (pore water) between the soil particles of the sandy soil layer because the target ground is sandy soil. Therefore, the drugs currently in use are firstly aqueous solutions, secondly low in viscosity and high in permeability, thirdly slow to extend the penetration range, and fourthly cured. When a drug is used, it has properties such as being ultrafine particles, and fifthly, the injected material is permanent without deterioration.

  As a method for solidifying the improvement target ground by infiltrating and injecting the agent having the above-described properties into the sandy soil as the improvement target ground, a) the double packer construction method disclosed in Patent Document 1, b) Examples thereof include a permeation solidification method, c) a super multi-point injection method disclosed in Patent Document 2, and d) a multi-stage multipacker method.

  B) Double packer construction method: (1) After drilling to a predetermined depth using a casing of around φ100mm, (2) Inserting the injection pipe and filling the seal grout into the hole, (3) Ringing into the hole Insert an outer pipe for injection having a discharge port covered with rubber, install the outer pipe, pull out the casing, and (4) insert an inner pipe with a heaper inside the outer pipe, then primary injection (CB liquid) (5) After completing the primary injection, expand the inner tube packer and perform osmotic injection (secondary injection: 5 to 10 liters per minute) from the inner tube through the outer tube. .

  B) The permeation solidification processing method is as follows: (1) After drilling to a predetermined depth using a casing of about φ100 mm, (2) An injection outer tube equipped with a special strainer and cloth sleeve packer is built in the hole, Pull out the casing, (3) After forming the sleep swell and packer made of cloth, insert an injection device with a discharge port fitted with a pipe double packer, and (4) Inject from the special strainer (5-15 liters per minute) To do.

  C) Super multi-point injection method: (1) After drilling to a predetermined depth using a casing of about φ100 mm, (2) Inserting an injection pipe, injecting a sealant into the hole, pulling out the casing, (3) Insert a thin multi-point injection hose (about 10) bundle with different injection depths into the hole, and (4) repeat the steps (1) to (3) above to repeat the multi-point injection hose bundle. (5) One unit of 32 consecutive points is injected simultaneously at an injection rate of 2 to 4 liters per minute per point.

D) The multi-stage multi-packer method is as follows: (1) after drilling to a predetermined depth using a casing, (2) installing a special injection packer and a multi-stage injection hole with a strainer structure, pulling out the casing, (3) After injecting the packer injection, the packer injection penetrates from the outer fabric to the external ground and maintains the sealing effect. (4) Injection of 20 to 30 liters per minute using an ultrafine particle grout agent Attempt osmotic injection at speed.
Japanese Patent Laid-Open No. 9-111747 JP-A-7-300849

  However, at the time of injection into the ground to be improved, the drug is in a non-hardened state and easily escapes from the discharge port provided in the injection pipe and leaks to the ground. Various devices for preventing the medicine from leaking to the ground at the time of injection into the ground to be improved are required. That is, in any of the above-described methods, for example, before performing the work of injecting the chemical into the ground to be improved, which is the original purpose, after drilling with a casing pipe, a sealant (cement / bentonite is placed in the hole. In order to maintain the packer effect after inserting an injection tube or an injection hose fitted directly with a heaper in the hole, the work process will increase, so in the injection solidification method, It will take a lot of time and money.

  In any of the methods described above, since the shape of the discharge port provided in the injection tube is a fine hole or a fine hole of the strainer, several holes or a single injection tube in a direction perpendicular to the axial direction of the injection tube are used. Since the drug is discharged only in a specific direction (several points in the axial direction and the horizontal direction), the directivity of the drug due to the discharge pressure is limited, the area for receiving the discharged drug on the ground to be improved is reduced, and the penetration efficiency And requires a lot of time to inject the drug. Therefore, the drug acceptance resistance to the ground to be improved, that is, the penetration speed into the ground to be improved, is not only the nature of the drug and the soil conditions, but also the area for receiving the drug to the ground to be improved, and the injection pipe which is the injection means The structure and area of the discharge port provided in the are also important factors. In other words, the discharge ports of the injection tube used in the past are all in one specific direction, and since the area for receiving the drug on the ground to be improved existing in the vicinity of the discharge port is small, the permeation rate per one discharge port However, there is a problem that the time required for injecting the drug is inevitably increased.

  On the other hand, when a plurality of discharge ports of the injection tube are arranged at arbitrary intervals in the longitudinal direction of the injection tube, the pressure is not uniform between the upper discharge port and the lower discharge port. There is a considerable difference between the discharge amount of fluid (medicine, compressed air, etc.) and the discharge amount of fluid discharged from the lower discharge port. If the discharge port of the injection tube is made of an elastic body such as rubber, the force that pushes the elastic body when fluid is discharged from a single discharge port As a result, the pressure is released, and the pressure at the discharge port located below the discharge port from which the fluid has been discharged drops rapidly, which makes it impossible to discharge the fluid. Therefore, conventionally, it has been necessary to repeatedly perform an operation process for stepping up the injection tube every injection process or an injection process after forming the packer.

  The object of the present invention is to prevent leakage of chemicals to the ground when injecting fluid (chemicals, compressed air, etc.) into the ground to be improved, for example, saving time and cost in the injection solidification method. This eliminates the need to repeat the conventional process of stepping up the injection tube for each injection process or the process of injecting after the formation of the packer, and a plurality of discharge ports are arranged at arbitrary intervals in the longitudinal direction of the injection pipe. In this case, the fluid can be discharged from any discharge port in a planar state in all directions on the outer periphery, and the fluid can be efficiently injected into the ground to be improved in a short time. An object of the present invention is to provide an injection tube and a grouting method using the injection tube, which are drastically shortened.

  When the drug is injected into the ground to be improved from the discharge port of the injection tube, the discharge amount per unit time of the drug discharged from the discharge port of the injection tube is limited by the penetration rate of the drug into the ground to be improved However, the inventor of the present invention increases the permeation speed of the medicine into the ground to be improved by increasing the receiving area of the medicine into the ground to be improved, and the medicine discharged from the discharge port of the injection tube Focusing on the fact that the discharge amount per unit time is several times the conventional amount, the present invention has been completed.

  That is, the injection tube of the present invention is an injection tube comprising an injection member in which an outer tube and an inner tube are arranged concentrically, and an anhydrous drilling blade installed at the tip of the injection member, A first annular slit outlet that communicates with the outer pipe flow path formed from the inner side of the outer pipe and the outer side of the inner pipe and is configured without using an annular elastic body on the outer peripheral surface; A plurality of second annular slit outlets that communicate with the inner pipe flow path formed inside the inner pipe and that do not use an annular elastic body are provided in the longitudinal direction of the injection pipe. It is characterized by being arranged at intervals of.

  In the injection pipe of the present invention, the first annular slit discharge port is connected to the distal end of the outer pipe flow path, and a plurality of introduction pipes disposed below the distal end of the outer pipe flow path, The plurality of first connection passages connected to each of the introduction pipes and one first annular gap portion connected to all of the plurality of first connection passages communicate with the outer pipe flow path. A configuration can be employed.

  In the injection pipe of the present invention, the second annular slit outlet is connected to a plurality of second connection passages arranged on the outer peripheral surface of the inner pipe flow path, and all of the plurality of second connection passages. It is possible to adopt a configuration that communicates with the inner pipe flow path through one second annular gap.

  In the first grouting method of the present invention, the grouting agent is injected simultaneously from the plurality of second annular slit outlets after drilling to a predetermined depth in the ground to be improved in the anhydrous state using the injection tube. The discharge is performed in a planar state in all directions on the outer periphery of the tube.

  In addition, when the grout agent is allowed to penetrate into the improvement target ground with the discharge pressure, the grout injection method for replacing the pore water and the grout agent while extruding and removing the groundwater (pore water) in the improvement target ground with the grout agent. Then, when the grout agent is infiltrated between the soil particles in the ground to be improved, the acceptance resistance (permeation resistance) of the grout agent due to the groundwater (pore water between the soil particles) is generated. Although the rate of penetration of the agent into the ground to be improved is limited, the inventors of the present invention are aware that it is possible to eliminate pore water even if compressed air is used instead of the grout agent. After removing the pore water that causes the resistance of acceptance of grout agent from the ground to be improved using compressed air, the grout agent is injected into the ground to be improved. The acceptance resistance of the grouting agent in the ground is further reduced, and as a result, the penetration rate of the grouting agent into the ground to be improved is further increased, so that the grouting agent can be more efficiently infiltrated into the ground to be improved. The present inventors have found what can be done and have completed the present invention.

  That is, the second grout injection method of the present invention comprises an injection member in which an outer tube and an inner tube are arranged concentrically, and an anhydrous drilling blade installed at the tip of the injection member, and an outer peripheral surface of the outer tube. Includes a first annular slit discharge port that communicates with an outer pipe flow path formed from the inner side of the outer pipe and the outer side of the inner pipe, and is configured without using an annular elastic body. A plurality of second annular slit discharge ports configured to communicate with the inner tube flow path formed inside the tube and without using an annular elastic body are arranged at arbitrary intervals in the longitudinal direction. A grout injection method using an injection tube, wherein the injection pipe is used to form a water in an anhydrous state with a predetermined depth in the ground to be improved, and then the inner pipe flow is in a state where the injection member and the outer peripheral ground are in close contact with each other. Compressed air is fed into the passage, and compressed air is simultaneously discharged from the plurality of second annular slit outlets. Is discharged in a planar state in all directions on the outer periphery of the injection pipe, and the interstitial water in the ground to be improved is pushed out by the compressed air and discharged, and then the compressed air is sent into the outer pipe flow path. Compressed air is discharged from one annular slit discharge port in a planar state in all directions on the outer periphery of the injection tube, and a grouting agent is fed into the inner tube flow path, from the plurality of second annular slit discharge ports. At the same time, the grouting agent is discharged in a planar state in all directions on the outer periphery of the injection tube.

  Using the injection tube of the present invention, for example, compressed air is discharged from a first annular slit discharge port provided in the injection tube, and a drug is supplied from a plurality of second annular slit discharge ports provided in the injection tube. When infiltrating into the ground to be improved, an air curtain is formed in all directions on the outer periphery of the first annular slit outlet provided in the injection pipe, and a plurality of second annular rings provided in the injection pipe Advantage that medicine discharged from the slit outlet becomes difficult to discharge upward from the outer peripheral direction of the first annular slit outlet provided in the injection pipe, and leakage of the medicine to the ground can be effectively prevented. There is.

  For example, when a fluid is injected into the ground to be improved using the injection pipe of the present invention, the injection pipe is simultaneously supplied from a plurality of second annular slit outlets arranged at arbitrary intervals in the longitudinal direction of the injection pipe. The fluid can be discharged in a planar state in all directions on the outer periphery of the outer pipe of the outer pipe, and the discharged fluid extrudes pore water in the ground to be improved with the discharge pressure, while Because it spreads in a ripple shape in the direction and expands three-dimensionally not only in the axial direction and the vertical direction of the injection tube but also in the axial direction and horizontal direction of the injection tube, the injection tube within the same time that could not be realized in the past As a result of the increase in the fluid receiving area to the ground to be improved, the penetration rate into the ground to be improved will increase, and from the injection pipe that will be an important factor for the fluid injection construction time The fluid discharge rate per unit time Becomes several times the method, the fluid can be efficiently injected in a short time in an improved target the ground, there is an advantage that the injection construction time of the fluid is shortened dramatically. In addition, by using the injection tube of the present invention, even in the osmotic injection with a long gel time of the chemical solution injection method conventionally used for temporary installation, the injection time of the drug can be greatly shortened, which is more economical. There is also an advantage that construction is possible.

  Using the first grout injection method of the present invention, for example, only the grout agent is simultaneously injected from the plurality of second annular slit discharge ports provided in the injection pipe drilled to a predetermined depth in the ground to be improved. When the grouting agent is discharged in a planar state in all directions, the grouting agent replaces the interstitial water between the soil particles and discharges the interstitial water, and from the plurality of second annular slit outlets provided in the injection pipe. At the same time, because the grouting agent is discharged in a planar state in all directions on the outer periphery of the injection tube, the acceptance resistance of the grouting agent in the ground to be improved decreases, and as a result, the penetration rate of the grouting agent into the ground to be improved Compared with the conventional method of injecting into groundwater with conventional groundwater, the grout agent can be efficiently infiltrated and injected into the ground to be improved in a short time. Can be shortened There is an advantage.

  Further, by using the second grout injection method of the present invention, the entire outer periphery of the injection tube is simultaneously provided from a plurality of second annular slit discharge ports provided in the injection tube drilled to a predetermined depth in the ground to be improved. The compressed air discharged in a plane state in the direction is replaced with the interstitial water between the soil particles, and the interstitial water is discharged, and the acceptance resistance of the grout agent is reduced. Since the grouting agent is discharged from the annular slit outlet at the same time in a planar state in all directions on the outer periphery of the injection tube, the acceptance resistance of the grouting agent in the ground to be improved further decreases, and as a result, the ground into the ground to be improved Compared with the conventional method of injecting into the existing ground with groundwater, the grout agent can be infiltrated and injected more efficiently in the ground to be improved in a shorter time compared to the conventional method of injecting into the ground with groundwater. Injection There is an advantage that while it is further dramatically reduced.

  Embodiments of the present invention will be described with reference to the drawings. The injection tube 1 of the present invention includes an injection member 2 and an anhydrous drilling blade 7 installed at the tip of the injection member 2 (FIG. 1).

  The injection member 2 has a double tube structure in which the outer tube 3 and the inner tube 4 are concentrically arranged. The injection member 2 includes a first injection member 2a having a first annular slit discharge port 5 disposed on the outer peripheral surface, and a plurality of second annular slits on the outer peripheral surface, which are positioned below the first injection member 2a. It is comprised from the 2nd injection | pouring member 2b which has arrange | positioned the discharge outlet 6. FIG. The injection member 2 may be formed by screwing the first injection member 2a and the second injection member 2b (FIGS. 1 and 4), or may be formed integrally. Good. Further, the second injection member 2b may be formed by screwing two or more portions 2c of the second injection member in which one second annular slit discharge port 6 is disposed (FIG. 1). 4), a plurality of second annular slit outlets 6 may be formed on one member.

  The first annular slit outlet 5 is configured without using an annular elastic body. For example, when the diameter of the outer tube 3 is 40 mm, the slit width of the first annular slit outlet 5 is preferably 0.3 to 1 mm. The first annular slit outlet 5 is, for example, connected to the tip of the outer tube flow path 3 a, arranged in four directions at intervals of 90 degrees on the outer periphery of the inner tube 4, and extending in the longitudinal direction of the inner tube 4. Four first connection passages 12, 12, 12 projecting perpendicularly to the longitudinal direction from the vicinity of the lower end of each of the introduction pipes 11, 11, 11, 11 and the four introduction pipes 11, 11, 11, 11. , 12, one first annular gap 13 connected to all four first connection passages 12, 12, 12, 12, and the upper end 13 a of the first annular gap 13, and the outside It communicates with the pipe flow path 3a (FIGS. 2A and 2C).

  For example, when compressed air is pumped to the outer pipe flow path 3a of the injection member 2, the compressed air is transferred from the outer pipe flow path 3a to the four introduction pipes 11, 11, 11, 11, and the four first connection passages. 12, 12, 12, 12, sent to one first annular gap 13, and from the first annular slit outlet 5 connected to the upper end 13 a of the first annular gap 13. The air curtain 5a, which will be described later, is formed by discharging in a planar state in all directions on the outer periphery.

  In addition, since the first annular gap 13 is present, the fluid pumped to the outer pipe flow path 3a of the injection member 2 is in a planar state from the first annular slit outlet 5 to all directions on the outer periphery of the injection pipe 1. The liquid is discharged at 5a.

  The second annular slit outlet 6 is also configured without using an annular elastic body. The slit width of the second annular slit outlet 6 is preferably 0.3 to 1 mm, for example, when the diameter of the outer tube 3 is 40 mm. The second annular slit outlet 6 is connected to, for example, the inner tube 4, and is disposed on the outer peripheral surface of the inner tube 4 at an interval of 90 degrees, and extends in the direction perpendicular to the axial direction of the inner tube 4. The passages 21, 21, 21, 21, one second annular gap 22 connected to all four second connection passages 21, 21, 21, 21, and the lower end 22 a of the second annular gap 22 And communicates with the inner pipe flow path 4a (FIGS. 3A and 3C).

  When a fluid is pumped to the inner pipe flow path 4a of the injection member 2, the fluid passes through the four second connection passages 21, 21, 21, 21 from the inner pipe flow path 4a to form one second annular gap portion. 22 is discharged from the second annular slit discharge port 6 connected to the lower end 22a of the second annular gap portion 22 in a planar state 6a in all directions on the outer periphery of the injection tube 1.

  For example, since there are a plurality of second annular gaps 22, 22, 22, 22, and 22, the fluid pumped to the inner pipe flow path 4a of the injection member 2 has a plurality of second annular slits. Simultaneously from each of the discharge ports 6, 6, 6, 6, the discharge is performed in the planar state 6 a, 6 a, 6 a, 6 a, 6 a in all directions on the outer periphery of the injection tube 1.

  Although it does not specifically limit as a fluid inject | poured in the improvement object ground using the injection pipe 1, For example, a grout agent, a neutralizing agent, compressed air etc. are mentioned, A grout agent and compressed air are preferable.

  In order to inject the fluid into the ground to be improved using the injection tube 1, for example, as shown in FIG. 7, a boring machine 31, an injection management device 32, a grout mixer 33, a grout pump 34, an injection flow rate / A fluid injection system 30 including a pressure recorder 35, a compressor 36 and a generator 37 needs to be connected to the injection pipe 1.

  In the first grout injection method of the present invention, for example, a plurality of second annular slit discharge ports 6, 6, 6, are formed after drilling to a predetermined depth in the ground to be improved in an anhydrous state using the injection tube 1. 6, 6 and 6 are simultaneously discharged in the planar state 6a, 6a, 6a, 6a, 6a in all directions on the outer periphery of the injection tube 1.

  In the first grout injection method of the present invention, after drilling directly to a predetermined depth in the ground to be improved using the boring machine 31 and installing the injection pipe 1 in the ground to be improved, for example, The grouting agent is pumped into the inner pipe flow path 4a, and the grouting agent is simultaneously injected into the injection tube 1 from each of the plurality of second annular slit discharge ports 6, 6, 6, 6 and 6 provided in the injection tube 1. It discharges in the planar state 6a, 6a, 6a, 6a, 6a to all directions of the outer periphery (FIG. 5). At this time, the grouting agent discharged from each of the plurality of second annular slit outlets 6, 6, 6, 6 and 6 is replaced by the grouting agent and the interstitial water while extruding the interstitial water in the ground to be improved. However, since the grouting agent is infiltrated and injected, the grouting agent can be infiltrated and injected into the ground to be improved more efficiently than the conventional method. At the same time, for example, compressed air is pumped to the outer pipe flow path 3 a of the injection pipe 1, and the compressed air is omnidirectional from the first annular slit outlet 5 provided in the injection pipe 1 to the outer circumference of the injection pipe 1. The liquid is discharged in the plane state 5a (FIG. 5). At this time, since the air curtain 5a is formed in all directions on the outer periphery of the injection tube 1 (FIG. 5), a plurality of second annular slit discharge ports 6, 6, 6, 6, below the air curtain 5a. Among the grouting agents discharged from each of the grouting agents 6, the grouting agents discharged exceeding the penetration speed into the ground to be improved are supplied from the plurality of second annular slit outlets 6, 6, 6, 6, 6. The grout agent escapes in the direction of the arrow 6b, and the escaped grout agent escapes upward from the outer circumferential direction of the first annular slit outlet 5 due to the air pressure of the air curtain 5a by the compressed air. Is blocked (FIG. 5), and leakage to the ground is effectively prevented.

  As the injection management device 32 connected to the injection pipe 1, for example, an integrated filter in which a compressed air filter, a pressure reducing valve control handle, and a pressure gauge are attached to a pipe portion connected to a compressed air flow path. Connect a regulator to one end of the filter regulator, and connect a controller that can control the discharge air volume per unit time of compressed air, and also sense the discharge air volume per unit time of compressed air on the discharge side of the controller Compressed air management device equipped with a digital amplifier that digitally displays the head, the numerical value of the discharge air volume per unit time of compressed air and the numerical value of the integrated discharge air volume, and a flow path switching valve on the upstream of the compressed air management device Attach the required number of flow path switching members with integrated cocks and switching handles, and connect the piping connected to the grout flow path. In this case, there is provided a flow path switching device that enables switching between compressed air to be pumped to the inner pipe flow path 4a of the injection pipe 1 and the grout agent by a handle operation. The discharge pressure to the discharge port 6 and the discharge amount per unit time of the fluid discharged from the annular slit discharge port 6 of the injection pipe 1 can be controlled, and the fluid to be pumped to the inner pipe flow path 4a of the injection pipe 1 can be controlled. There is no particular limitation as long as it can be switched.

  At the time of the grouting agent injection construction, for example, the grouting agent discharge pressure and the grouting agent discharge amount per unit time at each of the plurality of second annular slit discharge ports 6, 6, 6, 6 and 6 are injected. While checking with a flow rate pressure recorder, the injection management device 32 according to the discharge pressure of the grouting agent at each of the second annular slit outlets 6, 6, 6, 6 and 6 and the discharge amount of the grouting agent per unit time. The pressure control handle, the speed controller, and the like are operated to adjust the optimum discharge pressure of compressed air and the amount of compressed air discharged per unit time at the first annular slit outlet 5.

  Note that by operating the flow path switching handle of the flow path switching device, compressed air can also be pumped to the inner pipe flow path 4a of the injection pipe 1; It is also possible to simultaneously discharge compressed air from each of the second annular slit outlets 6, 6, 6, 6, 6 in the planar state 6a, 6a, 6a, 6a, 6a in all directions on the outer periphery of the injection tube 1. It is.

  In the second grout injection method of the present invention, for example, after the injection pipe 1 is drilled to a predetermined depth in the ground to be improved in an anhydrous state, the inner pipe flow is in a state where the injection member 2 and the outer peripheral ground are in close contact with each other. The compressed air is fed into the passage 4a, and the compressed air is simultaneously supplied from each of the plurality of second annular slit discharge ports 6, 6, 6, 6 and 6 to the outer circumference of the injection pipe 1 in the planar state 6a, 6a, 6a, 6a and 6a are discharged, the interstitial water in the ground to be improved is pushed out by compressed air and discharged, and then the compressed air is fed into the outer pipe flow path 3a and compressed air is discharged from the first annular slit outlet 5 Is discharged in all directions on the outer periphery of the injection tube 1 in the planar state 5a, and a grouting agent is fed into the inner tube flow path 4a, so that the plurality of second annular slit discharge ports 6, 6, 6, 6, 6 At the same time, grout agent is planar from all directions to the outer circumference of the injection tube 1 6a, 6a, 6a, 6a, is to discharge at 6a.

  In the second grout injection method of the present invention, first, the boring machine 31 is used to directly drill holes to a predetermined depth in the ground to be improved, and after the injection pipe 1 is installed in the ground to be improved, the injection member 2 and An operation of switching the handle of the flow path switching device provided in the above-described injection management device 32 connected to the injection pipe 1 is performed in a state where the outer peripheral ground is in close contact, for example, compression to the inner pipe flow path 4a of the injection pipe 1 Air is pumped, and compressed air is planarized from all of the plurality of second annular slit discharge ports 6, 6, 6, 6, 6 provided in the injection tube 1 in all directions on the outer periphery of the injection tube 1. It discharges in state 6a, 6a, 6a, 6a, 6a (Fig.6 (a)). At this time, the compressed air simultaneously discharged from each of the plurality of second annular slit discharge ports 6, 6, 6, 6, 6 provided in the injection pipe 1 pushes out the pore water in the ground to be improved. Since it is discharged, the pore water in the ground to be improved is reduced and the acceptance resistance of the grout agent is reduced (FIG. 6 (b)).

  Then, after closing the air supply valve of the compressed air to the inner pipe flow path 4a, the operation of switching the handle of the flow path switching device is performed, for example, the grouting agent is fed to the inner pipe flow path 4a of the injection pipe 1 The grouting agent is simultaneously discharged from each of the plurality of second annular slit discharge ports 6, 6, 6, 6, 6 in the planar state 6a, 6a, 6a, 6a, 6a in all directions on the outer periphery of the injection tube. (FIG. 6C). As a result, the grouting agent is injected into the ground to be improved where the acceptance resistance of the grouting agent is reduced, so that the infiltration rate is increased, and the grouting agent is further added to the conventional method of injecting into the ground with the groundwater. It is possible to efficiently infiltrate into the ground to be improved.

  At the same time, for example, compressed air is pumped to the outer pipe flow path 3a of the injection pipe 1, and the compressed air is discharged from the first annular slit outlet 5 in all directions on the outer periphery of the injection pipe 1 in a planar state 5a. (FIG. 6C). Thus, the compressed air discharged from the first annular slit outlet 5 forms an air curtain 5a (FIG. 6C), and therefore a plurality of second annular slit outlets below the air curtain 5a. Among the grouting agents discharged from each of 6, 6, 6, 6 and 6, the grouting agent discharged exceeding the penetration speed into the ground to be improved is a plurality of second annular slit outlets 6, The grout agent escapes from 6, 6, 6, 6 in the direction of the arrow 6b. The escape grout agent is generated by the first annular slit outlet 5 due to the air pressure of the air curtain 5a by the compressed air. The upward escape from the outer circumferential direction is blocked (FIG. 6C), and it is difficult to escape upward from the first annular slit discharge port 5, and leakage to the ground is effectively prevented.

  The injection pipe of the present invention and the grouting method using this injection pipe require, for example, measures to prevent liquefaction of sandy ground as a seismic measure, improvement of contaminated soil as a measure against pollution, and durability and high strength. It is useful for improvement of foundation ground directly under or near existing structures, improvement of foundation ground such as existing revetment / quayside cargo handling facilities / retaining walls, and improvement of ground where large construction machines cannot be used. .

It is a perspective view which shows the outline of one Embodiment of the injection tube of this invention. (A) The perspective view which shows the outline of an example of the 1st injection | pouring member used for the injection | pouring pipe | tube of this invention, (b) Sectional drawing of the AA surface of the said 1st injection | pouring member, (c) The 1st injection | pouring It is sectional drawing of the BB surface of a member. (A) The perspective view which shows the outline of an example of the 2nd injection member used for the injection tube of this invention, (b) Sectional drawing of CC plane of the 2nd injection member, (c) The 2nd injection It is sectional drawing of the DD surface of a member. It is a perspective view which shows a mode that a part of other one Embodiment of the injection tube of this invention was decomposed | disassembled. It is a figure explaining one aspect | mode of the form of injection | pouring in the case of implementing the 1st grout injection | pouring method of this invention. In the case where the second grout injection method of the present invention is carried out, (a) a schematic diagram for explaining one mode of a form at the time of simultaneously discharging compressed air from a second annular slit outlet, (b) a second Schematic explaining one aspect of the form at the time when the compressed air is completely discharged from the annular slit outlet, (c) One aspect of the form at the time of simultaneously discharging the grout agent from the second annular slit outlet FIG. It is a block diagram which shows an example of the injection | pouring operation system connected to the injection pipe of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection pipe 2 Injection member 2a First injection member 2b A plurality of second injection members 2c A part of the second injection member 3 Outer pipe 3a Outer pipe flow path 4 Inner pipe 4a Inner pipe flow path 5 First annular Slit outlet 5a Air curtain (planar state)
6 Second annular slit outlet 6a Planar state 7 Excavation blade 11 for water removal Introducing pipe 12 First connection passage 13 First annular gap 13a Upper end 21 of first annular gap Second connection passage 22 Second annular gap 22a Lower end 30 of second annular gap 30 Fluid injection system 31 Boring machine 32 Injection management device 33 Grout mixer 34 Grout pump 35 Injection flow rate / pressure recorder 36 Compressor 37 Generator

Claims (5)

An injection tube comprising an injection member in which an outer tube and an inner tube are arranged concentrically, and an anhydrous drilling blade installed at the tip of the injection member,
A first annular slit is formed on the outer peripheral surface of the outer tube, and communicates with an outer tube flow path formed from the inner side of the outer tube and the outer side of the inner tube, and without using an annular elastic body. A plurality of second annular slit discharge ports that communicate with an inner tube flow path formed inside the inner tube and that do not use an annular elastic body are provided on the injection tube. An injection tube characterized by being arranged at arbitrary intervals in the longitudinal direction. The first annular slit discharge port is connected to a tip of the outer pipe flow path, and is connected to a plurality of introduction pipes disposed below the tip of the outer pipe flow path, and each of the plurality of introduction pipes. The plurality of first connection passages and one outer annular gap connected to all of the plurality of first connection passages communicate with the outer pipe flow path. The injection tube according to 1. The second annular slit outlet has a plurality of second connection passages arranged on the outer peripheral surface of the inner pipe flow path, and one second annular passage connected to all of the plurality of second connection passages. The injection pipe according to claim 1 or 2, wherein the injection pipe communicates with the inner pipe flow path through a gap. After drilling to a predetermined depth in the ground to be improved in an anhydrous state using the injection tube according to any one of claims 1 to 3, the grouting agent is simultaneously supplied from the plurality of second annular slit outlets. A grout injection method characterized by discharging in a planar state in all directions on the outer periphery of the injection tube. An injection member in which an outer tube and an inner tube are arranged concentrically, and an anhydrous excavation blade installed at the tip of the injection member, and an outer peripheral surface of the outer tube includes an inner side of the outer tube and an inner tube of the inner tube A first annular slit outlet configured to communicate with an outer pipe flow path formed from the outside and without using an annular elastic body, and to an inner pipe flow path formed inside the inner pipe And a grout injection method using an injection tube in which a plurality of second annular slit discharge ports, which are configured without using an annular elastic body, are arranged at arbitrary intervals in the longitudinal direction,
After drilling to a predetermined depth in the ground to be improved using the injection pipe in a dry state, compressed air is fed into the inner pipe flow path in a state where the injection member and the outer peripheral ground are in close contact with each other, Compressed air is simultaneously discharged from the two annular slit outlets in a planar state in all directions of the outer periphery of the injection pipe, and the pore water in the ground to be improved is pushed out by the compressed air and discharged.
Thereafter, compressed air is fed into the outer pipe flow path, and the compressed air is discharged from the first annular slit outlet in a planar state in all directions on the outer periphery of the injection pipe, and a grout agent is supplied to the inner pipe flow path. And a grouting agent is discharged from the plurality of second annular slit discharge ports simultaneously in a planar state in all directions on the outer periphery of the injection tube.

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