JP5400083B2 - Ground improvement chemical injection pipe and ground improvement chemical injection method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a ground improvement chemical solution injection pipe and a ground improvement chemical solution injection method suitable for use in soil improvement work such as soil.

  If a large amount of spring water is generated during the construction, it will be impossible to excavate, or the outflow of sediment will be accelerated and the ground will collapse or the surrounding ground will sink. Moreover, when the strength of the ground is insufficient, the ground collapses due to the generation of earth pressure or water pressure, and construction cannot be performed.

  The chemical injection method is used for the purpose of “impermeable” and “strengthening” the ground in order to eliminate the above-mentioned problems.

  In addition, the chemical solution injection method is an indispensable method for improving the living environment and preventing natural disasters and for performing infrastructure maintenance work safely and economically.

  For example, in a construction that excavates underground in an urban area with a lot of buried objects, a continuous earth wall cannot be installed due to the buried objects, so if there is a defect in the retaining wall, the slope is excavated in steps or slopes. In addition, since the construction area is wide, infrastructure construction and maintenance of existing buried objects are difficult in urban areas. On the other hand, a chemical injection method that is small in size and excellent in versatility and easy to construct can facilitate the underground construction and shorten the construction period as an auxiliary construction method.

  Conventionally, a boring machine has been used for excavating the ground as a premise for injecting chemicals (Japanese Patent Laid-Open No. 2007-2555: Patent Document 1). In this boring machine, drilling is performed by rotating a boring rod directed vertically downward, and at that time, drilling water is fed from an injection hose connected to a swivel joint at the upper end to make a hole.

Regarding the medicine injection method, the double packer method is the most effective method. In this double packer system, a seal grout that is softly cured is filled into a hole that has been previously drilled by a casing rod having a large diameter (outer diameter of 100 mm or more). After that, a strainer tube is inserted and buried in this seal grout, and the casing rod is pulled out. When the filled seal grout is softened, an inner tube with a packer is inserted into the strainer tube and fresh water is sent to each strainer hole. Cracks are generated in the seal grout (this process is called cracking).
After that, a hose with a packer (a double packer that can be expanded and contracted by high-pressure gas above and below the strainer hole) is inserted to the lower end in the strainer tube, and the packer is used in the lower layer injection step for sealing The primary injection (coarse injection) is performed through the cracks while discharging the injection grout (chemical solution) from the strainer hole into the ground. After the completion of injection per step, the packer is loosened and pulled up to the next step, and then, as in the previous step, the packer, injection, packer loosening, and step-up are repeated until the uppermost step is injected. When the primary injection material is hardened, the injection tube with a double packer is again inserted up to the first step of the strainer tube and subjected to secondary injection (osmotic injection).
In this way, while gradually raising the injection tube step by step from the lower injection step to the upper injection step, sealing is performed using the packer at each step to discharge the injection grout (chemical solution) and through the crack to the surrounding ground inject.

However, in the double packer method described above, the procedure of drilling the injection hole by boring in advance and pulling out the casing rod and then setting the strainer pipe in addition to cracking, primary injection, and secondary injection are complicated. In addition, the strainer pipe of the PVC pipe cannot be pulled out and is left behind, which causes a problem in environmental conservation. Moreover, there is a problem that considerable labor and construction cost are required for the installation.
The double packer method also allows step-down injection, but in reality, the injection tube cannot be inserted into the deep part in sequence due to the weak rigidity of the hose, and in addition, every time the double packer is opened or closed, the chemical solution leaks. Has the disadvantage of making the work difficult.

  On the other hand, the strainer pipe is installed directly in the ground as a boring rod instead of the indirect installation method in which the strainer pipe is inserted and installed after casing drilling (boring). There is a step-down type injection method in which seal grout is performed immediately afterwards, and then the injection is performed while descending from the upper stage.

  JP-A-9-88056 (Patent Document 2) proposes a chemical solution injection method. However, in the method of Patent Document 2, since the problem of clogging is likely to occur in the surrounding discharge holes, the applicant has proposed a method for a new system to be described later.

  The strainer tube used in the construction method described in Patent Document 2 is tightly slidably fitted into the strainer tube by, for example, providing a sealing material on the outer periphery of the inner tube so as to close the peripheral surface discharge hole from the inside. Is. Then, drilling is performed while discharging drilling water through the tip discharge hole of the inner pipe and strainer pipe, and after installing the strainer pipe at a predetermined depth, the seal grout is pumped while pulling up the inner pipe and from the tip of the inner pipe to the tip of the strainer pipe And it inject | pours in a drilling clearance gap from a surrounding surface discharge hole. After the injection, the inner pipe is lowered stepwise from the upper part of the injection range of the strainer pipe, the injection grout (chemical solution) is pumped, the seal grout is broken, and step injection is performed on the surrounding ground.

  In this method, the inner pipe is moved up and down until the injection is completed, but the outer pipe (strainer pipe) in the ground is not moved up and down, so that the sealing effect between the ground and the outer pipe is not lost. In addition, since the ground itself injected to inject from the upper stage after the seal injection is a system that exhibits a packer effect, an injection effect higher than that of the double packer method can be obtained. That is, the chemical solution is injected horizontally and easily injected into a predetermined place.

  However, even with the technique of the above-mentioned Patent Document 2, since the injection tube (inner tube) is a single tube, the instantaneous linking liquid cannot be used when the injection range is deep. In other words, the chemical solution to be injected is mixed with the main agent and the curing agent at the construction site and injected, but if it takes a long time to cure, there will be no problem with the injection, but the instantaneous setting chemical solution that cures in a short time. In this case, the chemical solution is hardened for the first time before reaching the deep part of the injection tube, and the chemical solution cannot be injected into the ground at the target depth.

  Moreover, in the technique of patent document 2, the seal rubber is baked on the surface of the inner pipe, and the inner pipe is closely fitted in the outer pipe (strainer pipe). When fine sand enters, the sliding resistance of each other increases, so it is difficult to move the inner pipe up and down with respect to the outer pipe inserted into the ground by boring, resulting in reduced work efficiency. Can be considered.

JP 2007-2555 A JP-A-9-88056

In view of the above-described problems, the present invention can prevent the earth and sand in the ground from flowing into the outer tube, easily insert and remove the inner tube into and from the outer tube, and even if the injection range is deep, The present invention provides a ground improvement chemical solution injection tube and a ground improvement chemical solution injection method that can be injected into the ground.

The present invention relates to a ground improvement chemical injection pipe and a ground improvement chemical injection method .

The ground improvement chemical injection pipe of the present invention is provided with an outer tube body provided with a plurality of peripheral surface discharge holes in the periphery, and a side surface discharge hole at least in the lateral direction inserted into the outer tube body. In the ground improvement chemical injection pipe having an inner tube body,
The outer tube body is a joined body of outer tube members having a configuration in which an end portion of one outer tube member is inserted and joined into an end portion of the other outer tube member,
A strainer hole communicating from the inside of the outer tube body to the outside is formed at the corresponding portion at the end of one outer tube member and the end of the other outer tube member in the coupled state, and one and the other outer tube members A valve member that normally closes the strainer hole between the ends of the tube and opens the strainer hole when the internal pressure of the outer tube is higher than the external pressure,
Provided on the side surface of the distal end portion of the inner tube body are a plurality of seal members that are slidably in close contact with the inner surface of the outer tube body at a distance from each other. A side-facing side discharge hole that communicates with the side surface is provided,
When a pressurized chemical solution is introduced into the inner tube during the injection of the chemical solution, the drug solution is discharged from the side discharge holes to increase the internal pressure in the outer tube between the seal members, and the valve member of the strainer hole is opened. The chemical solution is injected from the strainer hole into the surrounding ground outside the outer tube body ,
At the tip of the outer tube body, a tip discharge hole that opens forward and a boring bit are provided,
The distal end portion of the inner tube body is provided with a second discharge hole that opens forward and a structure capable of closing the second discharge hole,
The outer tube and the inner tube are provided with a locking structure that is fixed in the rotational direction relatively when drilling,
The locking structure for fixing in the rotational direction relatively at the time of drilling is formed with a rotation stop projection on one side and a rotation stop groove on the other side at a position corresponding to the time of drilling the outer tube and the inner tube. It is a chemical solution injection pipe for ground improvement characterized by being a thing.

In the present invention, the outer tube body has a male screw formed on the outer peripheral surface of the end portion of one outer tube member, and a valve member made of an elastic material covering the strainer hole is provided on the outer peripheral surface. An internal thread is formed on the inner peripheral surface of the end of the outer tube member,
It is preferable that the male screw is screwed into the female screw to connect one and the other outer tube members to each other so that the valve member is sandwiched between the end portions of the one and the other outer tube members. is there.

  In the present invention, the inner tube has an inner / outer double tube structure in which a second inner tube is provided outside the first inner tube, and the first passage passes through the space in the first inner tube. The space between the first inner tube outer peripheral surface and the second inner tube outer peripheral surface is defined as a second passage, and liquid can be supplied to each of the first passage and the second passage. The front end portion of the inner tube is provided with a monitor for mixing and mixing the liquids sent through the first passage and the second passage in the internal space, and the monitor is spaced apart from each other. It is preferable to have a structure in which a side discharge hole in a lateral direction that communicates from the inside of the monitor to the outer side surface is provided at a position within the interval between the plurality of seal members provided.

In the present invention, the main agent is fed to one of the first passage and the second passage, and the curing agent is fed to the other,
In the monitor of the front end portion of the inner tube, the chemical solution composed of the main agent and the curing agent fed through the first passage and the second passage is mixed and mixed in the internal space, and a plurality of portions provided on the side of the monitor It is preferable that the mixed chemical solution is discharged from the side surface discharge hole at the position in the interval of the seal member toward the strainer hole of the outer tube body.
In the present invention, the structure capable of closing the second discharge hole is larger in diameter than the inner diameter of the second discharge hole, and falls down by the own weight in the inner tube body facing forward. It is preferable that the valve body is fitted into the discharge hole.

In the present invention, a boring bit is provided at the distal end portion of the outer tubular body, a second discharge hole is opened in the forward direction at the distal end portion of the monitor, and the first inner tubular body is moved forward and backward in the monitor. A movable valve capable of opening and closing the tip opening and the second discharge hole;
The movable valve is a hollow body whose front and rear surfaces are closed, the front side surface and the rear side surface are formed with communication holes into the hollow, and the peripheral surface is provided with a seal member for the inside of the monitor. The entire valve is spring-backed by an elastic body, and the second discharge hole can be opened and closed at the front end, and the front end opening of the first inner tube body can be opened and closed at the rear end. ,
When drilling with a boring bit by rotating the outer tube body, the drilling water is allowed to flow into the second passage while the movable valve closes the first passage, and the drilling water is passed through the rear portion of the movable valve. From the side communication hole through the hollow and further through the front side communication hole, the drilling water flows and is supplied to the boring bit,
On the other hand, when the chemical solution is injected, the movable valve is driven to open the first passage and the second passage by pressurizing and flowing the main agent and the curing agent of the chemical solution through the first passage and the second passage. It is preferable that the discharge hole is closed, the main agent and the curing agent are mixed in the monitor, and the chemical solution mixed from the side discharge hole facing the side is supplied into the ground via the strainer hole of the outer tube. It is.

In the present invention, a boring bit is provided at the distal end of the outer tube body, a valve body that can be moved back and forth in the monitor to open and close the second discharge hole, and a spring that biases the valve body forward And
A valve seat is provided at a position ahead of the side discharge hole in the lateral direction on the inner peripheral surface of the monitor, and the valve body is brought into close contact with the valve seat by a biasing force of a spring when the valve body is positioned ahead in the monitor. The second discharge hole is closed, and at the same time, a contact portion is provided on the inner side of the check valve mounting portion at the distal end portion of the outer tube body, and the valve body contacts the contact portion (cross valve seat). When the valve body moves backward in the monitor against the biasing force of the spring, the valve body is separated from the valve seat and the close contact is released, whereby the second discharge hole is opened. West,
When drilling to rotate the boring bit in conjunction with the rotation of the outer tube, the inner tube is moved forward to position the monitor in the outer tube tip, and a plurality of sealing members and the outer Close the side discharge hole of the monitor in close contact with the inner peripheral surface of the distal end portion of the tube body, and bring the valve body in the monitor into contact with the abutting portion so that the valve body is rearward from the valve seat And the second discharge hole is opened to allow the drilling water to flow through the first passage and the second passage of the inner tube, and the drilling water is supplied to the valve body and the seating surface in the monitor. To the second discharge hole and supply to the boring bit,
On the other hand, when injecting a chemical solution, the inner tube body is moved backward in the outer tube body, and a strainer hole is positioned at an interval position between a plurality of seal members provided at intervals before and after the side surface discharge hole of the monitor. In the monitor, the valve body is brought into close contact with the valve seat by the urging force of the spring, and the main solution of the chemical and the curing agent are applied to the first passage and the second passage under pressure to flow. It is preferable that the main agent and the curing agent are mixed in the monitor, and the chemical solution mixed from the side discharge hole in the lateral direction is supplied into the ground via the strainer hole of the outer tube body.

The ground improvement chemical injection pipe of the present invention is provided with an outer tube body provided with a plurality of peripheral surface discharge holes in the periphery, and a side surface discharge hole at least in the lateral direction inserted into the outer tube body. In the ground improvement chemical injection pipe having an inner tube body,
The outer tube body is a joined body of outer tube members having a configuration in which an end portion of one outer tube member is inserted and joined into an end portion of the other outer tube member,
A strainer hole communicating from the inside of the outer tube body to the outside is formed at the corresponding portion at the end of one outer tube member and the end of the other outer tube member in the coupled state, and one and the other outer tube members A valve member that normally closes the strainer hole between the ends of the tube and opens the strainer hole when the internal pressure of the outer tube is higher than the external pressure,
Provided on the side surface of the distal end portion of the inner tube body are a plurality of seal members that are slidably in close contact with the inner surface of the outer tube body at a distance from each other. A side-facing side discharge hole that communicates with the side surface is provided,
When a pressurized chemical solution is introduced into the inner tube during the injection of the chemical solution, the drug solution is discharged from the side discharge holes to increase the internal pressure in the outer tube between the seal members, and the valve member of the strainer hole is opened. The chemical solution is injected from the strainer hole into the surrounding ground outside the outer tube body,
At the tip of the outer tube body, a tip discharge hole that opens forward and a boring bit are provided,
The distal end portion of the inner tube body is provided with a second discharge hole that opens forward and a structure capable of closing the second discharge hole,
The outer tube and the inner tube are provided with a locking structure that is fixed in the rotational direction relatively when drilling,
The tip discharge hole at the tip of the outer tube body is provided with a check valve that opens with the pressure of drilling water supplied when drilling with a boring bit and blocks the flow from the outside to the tip discharge hole. It is a chemical injection pipe for ground improvement.

In addition, the ground solution improvement chemical injection method of the present invention includes an outer tube body provided with a plurality of peripheral surface discharge holes, a side discharge hole inserted at least in a lateral direction at a distal end portion inserted into the outer tube body. In the ground improvement chemical solution injection pipe having an inner tube body provided with
The outer tube body is a joined body of outer tube members having a configuration in which an end portion of one outer tube member is inserted and joined into an end portion of the other outer tube member,
A strainer hole communicating from the inside of the outer tube body to the outside is formed at the corresponding portion at the end of one outer tube member and the end of the other outer tube member in the coupled state, and one and the other outer tube members A valve member that normally closes the strainer hole between the ends of the tube and opens the strainer hole when the internal pressure of the outer tube is higher than the external pressure,
At the same time, the front end portion of the outer tube body is provided with a front end discharge hole that opens forward, and a boring bit,
Provided on the side surface of the distal end portion of the inner tube body are a plurality of seal members that are slidably in close contact with the inner surface of the outer tube body at a distance from each other, and the inner position of the inner tube body from the inside of the inner tube body A side discharge hole in the lateral direction communicating with the outer side surface is provided, and at the same time, a second discharge hole that opens in the forward direction at the distal end portion of the inner tubular body, and a structure capable of closing the second discharge hole Provided,
The outer tube body and the inner tube body are provided with a locking structure that is relatively fixed in the rotational direction when drilling , and the locking structure that is relatively fixed in the rotational direction when drilling is provided with the outer tube body and the inner tube body. In the position corresponding to the drilling of the tubular body, a rotation stop projection is formed on one side and a rotation stop groove is formed on the other side ,
Drilling the ground with the boring bit by simultaneously rotating the outer tube and the inner tube while pumping drilling water from the second discharge hole to the boring bit through the inner tube;
Adding the outer tube and the inner tube until the ground drilling depth reaches a predetermined depth;
After the drilling depth reaches a predetermined depth, the pressurized chemical solution is introduced into the inner tubular body when the chemical solution is injected while the outer tube body is left in the drilled hole, and the chemical solution is supplied to the side surface discharge hole. A chemical solution step of injecting the chemical solution from the strainer hole into the ground around the outside of the outer tube body by opening the valve member of the strainer hole by increasing the internal pressure in the outer tube body between the seal members This is a ground solution improving chemical solution injection method.

[Principle of the present invention]
The principle of the present invention will be described.
In the chemical injection method, by injecting a solidified material such as voids or cavities between the soil particles in the sand ground, the soil particles are connected and integrated and strengthened. Prevent water. In addition, the caking agent breaks into the soft ground in a branch shape so as to drive a wedge, and the surrounding ground is consolidated and strengthened, and it is improved by a synergistic effect due to the strength expression of the caking agent, thereby improving the earth strength.

  However, the conventional chemical solution injection method is an unreliable method because its effect often depends on the ground conditions. The reason is that when the caking agent is released into the ground, it cannot be artificially controlled, and it is injected from a place with low resistance even if it is not subject to improvement, just like “string breakage”. Sometimes, it was not uniform. Moreover, while this factor was clear, the defect could not be improved for many years.

The type and characteristics of the chemical solution to be injected will be described.
[Form of medicinal solution]
As a form of the chemical solution, there are a “solution type” suitable for injection into a relatively large gap such as sandy soil, and a “suspension type” suitable for soil having a very small gap such as viscous soil. In the gravel layer having a larger gap, the “suspension type” may be pre-injected and then packed, and then the “solution type” may be injected to increase the water stoppage.

[Geltime]
In the chemical injection, the main agent and the curing agent are mixed, and gradually loses fluidity (muddy shape) while increasing in viscosity with the passage of time, and eventually solidifies. The elapsed time from this mixing until the fluidity is lost is called “gel time”.

The gel time is selected empirically depending on whether the chemical solution penetrates in a wide range within the ground gap or stops within a limited range. However, since the permeability varies depending on the size of the gap, the gel time is chosen depending on the ground conditions.
Instantaneous chemical solution: loses fluidity (solidification) within 60 seconds.
Medium binding solution: loses fluidity within 10 minutes.
Slow binding chemical (long setting): It takes 10 minutes or more to lose fluidity.

The inventor has improved the following points that could not be solved in the past.
(1) Improvement of sealing performance of inner tube In the chemical solution injection method described in Patent Document 2 above, since the chemical solution is injected from the upper stage of the ground after seal injection, the injected ground itself is a system that exhibits a packer effect, and is high An injection effect can be obtained. However, since the seal material baked on the outer surface of the inner pipe and the inner surface of the outer pipe (strainer pipe) are fitted to each other, if the fine soil flows into the pipe due to the groundwater pressure, the inner pipe is difficult to be inserted and removed. Therefore, the present invention has been developed to solve this problem.

(2) The entire gel time (from instant setting to slow setting material) can be used for ground improvement.
The inventor has developed the chemical solution in consideration of the fact that the chemical solution injection method has a great influence on the injection effect due to the form of the chemical solution and the gel time. This is a new chemical injection pipe for improvement. In other words, depending on the ground conditions, the inner tube body can be changed to a conventional single tube as a method to enable the use of “solution type chemical solution, suspension chemical solution” and the gel time of the whole chemical solution from “instantaneous to slow”. In addition, a double pipe has been developed, and it is easy to insert and remove without burning a sealing material to the inner pipe as in the technique described in Patent Document 2.

(3) Inflow prevention of earth and sand from the outer tube tip If the strainer tube tip is open, earth and sand will flow into the tube when the inner tube is moved up and down and attached / detached. In order to prevent this, it is preferable to provide a special check valve.

(4) Prevention of slipping out of the inner tube Since the inner tube fitted to the outer tube during boring or injection may be pulled out due to the injection pressure and hinder the work. Provide a swivel sub with an anti-fall-off bracket in between.

(5) Prevention of detachment due to reverse rotation of the inner tube Fine sand enters the boring because the outer tube and the inner tube are fitted together, but the screw on the inner tube rotates backward due to the rotation of the outer tube. It is preferable to add a device for preventing the phenomenon of falling out to the function of the swivel sub.

  According to the ground solution improving chemical injection pipe of the present invention, the outer tube member is joined by inserting the end portion of one outer tube member into the end portion of the other outer tube member and joining the outer tube member. A strainer hole that communicates from the inside of the outer tube body to the outside is formed at a corresponding location at the end of one outer tube member and the end of the other outer tube member that are joined, and one and the other Normally, the strainer hole is closed between the ends of the outer tube member, and a valve member that opens the strainer hole when the internal pressure of the outer tube body is higher than the external pressure is mounted. Provided with a plurality of seal members that are slidably in contact with the inner surface of the outer tube body at intervals before and after, and provided with discharge ports in the lateral direction that communicate from the inside of the inner tube body to the side surfaces at positions within the space. , By introducing a pressurized chemical solution into the inner tube from a pump or the like at the time of injecting the chemical solution, Discharge from the surface discharge hole to increase the internal pressure in the outer tube between the seal members and open the valve member of the strainer hole, whereby the chemical solution is injected from the strainer hole into the surrounding ground outside the outer tube body. I try to do it.

  Therefore, the valve member is closed at the time of drilling that does not apply much pressure when bowling and inserting the ground with respect to the outer tube body and the inner tube body or before the injection of the drug, Since the valve function increases as the water pressure increases, earth and sand and muddy water do not enter the outer tube from the strainer hole due to the pressure in the ground, and this does not hinder the inner tube from moving up and down.

  Further, by applying pressure in the inner tube, the valve member of the strainer hole is opened, and the seal grout and the chemical solution can be sufficiently injected into the ground.

  When a drilling bit is provided at the tip of the outer tube and drilling water is fed when drilling by rotating the outer tube, the drilling water is mainly fed from the tip opening (second discharge hole) of the inner tube. The valve member of the strainer hole of the outer tubular body does not open and the drilling water does not come out from the strainer hole, and the drilling is not hindered.

In addition, a structure is provided in which a second discharge hole at the front end of the inner tube body is opened and the second discharge hole can be closed, and drilling water is discharged from the second discharge hole during drilling. With the boring bit, the hole is smoothly drilled. On the other hand, when the chemical solution is injected, the second discharge hole is closed to prevent the inflow of earth and sand into the pipe and the chemical solution can be reliably injected into the ground.
Further, the locking structure for fixing in the rotational direction relatively at the time of drilling has a rotation stop protrusion on one side and a rotation stop groove on the other side at a position corresponding to the time of drilling the outer tube and the inner tube. Can be formed.

  Further, the outer tube body has a male screw formed on the outer peripheral surface of the end portion of one outer tube member, and a valve member made of an elastic material covering the strainer hole is provided on the outer peripheral surface, and the other outer tube member is provided. Assuming that an internal thread is formed on the inner peripheral surface of the end portion of the first and second outer tube members, the male screw is screwed to the female screw, and one and the other outer tube members are connected to each other. The valve member is sandwiched between the end portions of the outer pipe member and protected by sandwiching the valve member between the end portions of the outer pipe member, and the soil and sand in the ground located at a predetermined depth can be protected. Since friction does not work between them, damage can be prevented. Further, if the outer tube members are removed, the valve member can be exposed and easily replaced, so that maintainability can be improved.

  Further, the structure capable of closing the second discharge hole is larger in diameter than the inner diameter of the second discharge hole, and falls in the inner tube body facing forward downward by its own weight, so that the second discharge hole A simple structure can be obtained by using a valve member that fits into the hole.

  In the present invention, the inner tubular body has an inner / outer double tube structure in which a second inner tubular body is provided outside the first inner tubular body, and the space in the first inner tubular body is the first. And a space between the outer peripheral surface of the first inner tube body and the outer peripheral surface of the second inner tube body as a second passage, and liquid is supplied to each of the first passage and the second passage. In addition, a monitor is provided at the tip of the inner tube so that the liquids fed through the first passage and the second passage are mixed and mixed in the internal space. With a structure that has a discharge port in the direction of the side that communicates from the inside of the monitor to the side surface at a position within the interval between the multiple seal members that are placed with the monitor in place so that the drug solution can be mixed regardless of the gel time The chemical solution can be selected and the appropriate chemical solution can be injected.

  The main agent is sent to one of the first passage and the second passage, and the curing agent is sent to the other, and the liquid is fed through the first passage and the second passage in the monitor of the tip of the inner tube. The chemical solution composed of the main agent and the curing agent is merged and mixed in the internal space, and is directed to the strainer hole of the outer tube from the discharge hole in the lateral direction of the interval between the plurality of seal members provided on the monitor side surface. The mixed chemical solution can be discharged.

  In addition, a boring bit is provided at the distal end of the outer tubular body, a second discharge hole is opened at the front end of the monitor, and a movable valve that can be moved back and forth in the monitor to close the second discharge hole. The movable valve is a hollow body whose front and rear surfaces are closed, the front side surface and the rear side surface are formed with communication holes into the hollow, and the peripheral surface is provided with a seal member for the inside of the monitor. The whole movable valve is elastically ejected rearward by an elastic body, the second discharge hole can be closed at the front end portion, and the front end opening of the first inner tube body can be closed at the rear end portion By being configured, the second discharge hole closing structure can be driven and controlled by the liquid injection pressure into the inner tube, and it is not necessary to mount a separate valve member, which is convenient.

  In the present invention, a boring bit is provided at the distal end of the outer tubular body, a second discharge hole is opened in the forward direction at the distal end of the monitor, and the first inner tubular body is moved forward and backward in the monitor. A movable valve capable of opening and closing the front end opening and the second discharge hole is provided, and the movable valve is a hollow body whose front surface and rear surface are closed, and communication holes into the hollow are formed on the front side surface and the rear side surface. And a seal member for the inside of the monitor is provided on the peripheral surface, the entire movable valve is elastically repelled rearward by an elastic body, the second discharge hole can be opened and closed at the front end portion, and the rear end The opening of the first inner tube body is configured to be openable and closable at the portion, and when the outer tube body is rotated and drilling with a boring bit, the movable valve closes the first passage, The drilling water is poured into the passage, and the drilling water communicates with the rear side surface of the movable valve. From the inside of the hollow and through the communication hole on the side surface of the front portion, the drilling water flows and is supplied to the boring. On the other hand, when the chemical solution is injected, the main agent of the chemical solution is placed in the first passage and the second passage. The movable valve is driven by applying pressure to flow the movable valve to open the first passage and the second discharge hole is closed, the main agent and the curing agent are mixed in the monitor, and the discharge is directed to the side. The chemical liquid mixed from the hole can be supplied into the ground via the strainer hole of the outer tube body, and the chemical liquid can be appropriately injected without requiring a complicated control device.

In the present invention, a boring bit is provided at the distal end portion of the outer tube body, a valve body that can move forward and backward in the monitor to open and close the second discharge hole, and a spring that biases the valve body forward A valve seat is provided on the inner peripheral surface of the monitor at a position ahead of the side discharge hole in the lateral direction, and when the valve body is positioned at the front of the monitor, the valve body is seated by a biasing force of a spring. The second discharge hole closes closely, and at the same time, a contact portion (cross valve seat) is provided on the inner side of the check valve mounting portion at the distal end portion of the outer tube body, and the valve body is in contact with the contact portion. When the valve body moves rearward in the monitor against the biasing force of the spring, the valve body is separated from the valve seat, and the close contact is released. The structure can be opened. At the same time, when drilling to rotate the boring bit in conjunction with the rotation of the outer tube, the inner tube is moved forward to position the monitor within the outer tube tip, and a plurality of seal members The valve body by closing the side surface discharge hole of the monitor in close contact with the inner peripheral surface of the distal end portion of the outer tube body and bringing the valve body in the monitor into contact with the contact portion The second discharge hole is opened by moving it backward from the seat, and the drilling water is allowed to flow through the first passage and the second passage of the inner tube body. From the space between the seating surface and the second discharge hole, the liquid is supplied to the boring bit. On the other hand, when injecting the chemical solution, the inner tube is moved backward in the outer tube to A plurality of seal members provided at intervals before and after are positioned at positions within the interval. Pressure is applied to the first and second passages with the chemical main agent and curing agent so that the rena holes are located and the valve body is in close contact with the valve seat by the biasing force of the spring in the monitor. The main agent and the curing agent are mixed in the monitor, and the mixed chemical solution is supplied to the ground via the strainer hole of the outer tube body.
This configuration improves the operability and malfunction during drilling / injection because the valve body can be reliably opened and closed by lowering and raising the inner pipe body (if it moves forward). It is easy to maintain and can be used to reduce the cost of monitor production.
Further, after the injection is completed, it is possible to return to the state of drilling simply by pushing down the inner tube body, and it is possible to execute the drilling, seal injection, and hardener injection reasonably repeatedly at any time.
It is also an important factor to enable this repetitive work in the injection work.

  Further, in the present invention, the check valve that opens the tip discharge hole at the tip of the outer tube body with the pressure of the drilling water supplied when drilling with the boring bit and blocks the inflow to the tip discharge hole from the outside. It is possible to prevent the earth and sand from flowing into the outer tube from the boring bit to prevent the workability from being lowered.

It is a whole lineblock diagram of injection plant equipment using a chemical solution injection pipe for ground improvement concerning an embodiment of the present invention. (A) is an assembly drawing of a chemical solution injection pipe for ground improvement according to the first embodiment (applied to the first construction form), and (b) is a cross-sectional view taken along line AA of (a). . It is decomposition | disassembly explanatory drawing of the chemical | medical solution injection tube for the ground improvement. It is explanatory drawing of the outer tube | pipe member which comprises the outer tube | pipe body in the chemical | medical solution injection tube for the ground improvement. It is an expanded sectional view which follows the BB line of FIG.2 (b), Comprising: It is explanatory drawing of the connection structure of the edge parts of the outer tubular body in the chemical | medical solution injection tube for the ground improvement. It is explanatory drawing of the swivel and swivel sub for suspension support of the chemical | medical solution injection tube for the ground improvement, Comprising: (a) is longitudinal explanatory drawing, (b) is the A direction expansion explanatory drawing of (a), (c) is. It is a cross-sectional view which follows the B direction of (a). It is explanatory drawing of the drilling procedure using the chemical | medical solution injection tube for the ground improvement. It is explanatory drawing of the sealing procedure (seal grout injection | pouring) using the chemical | medical solution injection tube for the ground improvement. FIG. 9 is an explanatory diagram of a state around a monitor and a boring bit during the sealing procedure of FIG. 8. It is explanatory drawing of the chemical | medical solution injection | pouring procedure using the chemical | medical solution injection tube for the ground improvement. (A)-(e) is each explanatory drawing of the addition procedure of the inner tube body at the time of drilling of the chemical | medical solution injection tube for ground improvement, and an outer tube body. It is explanatory drawing of the chemical | medical solution injection tube for ground improvement which applies to the 2nd Embodiment of this invention (it applies to the 2nd construction form), (a) is an assembly drawing, (b) is an exploded view of an outer tubular body, (C) is an exploded view of the inner tube. It is explanatory drawing at the time of drilling of the chemical | medical solution injection pipe for ground improvement, (a) is explanatory drawing of a drilling procedure, (b) It is explanatory drawing of the distribution route of drilling water. It is explanatory drawing of the sealing | blocking procedure of the chemical | medical solution injection tube for the ground improvement, and the distribution route of a main ingredient and a hardening | curing agent. It is explanatory drawing of the injection | pouring procedure of the chemical | medical solution for ground improvement by the chemical | medical solution injection pipe for ground improvement. It is an assembly drawing of the chemical | medical solution injection tube for ground improvement concerning the 3rd Embodiment of this invention (applied to the 3rd construction form), Comprising: It is explanatory drawing of the drilling procedure using the chemical | medical solution injection tube for ground improvement. . It is explanatory drawing of the sealing procedure (seal injection | pouring / hardening agent injection | pouring) using the chemical | medical solution injection tube for ground improvement of FIG. FIG. 17 is an assembly diagram of a monitor constituting the ground solution improvement chemical injection pipe of FIG. 16. It is an exploded view of the monitor. It is a monitor outer tube for housing the monitor and attaching a boring bit to the tip of the outer tube body, (a) is a longitudinal sectional view, and (b) is a sectional view taken along line AA ′ of (a). . It is explanatory drawing which cut through the check valve and the boring bit vertically, (a) shows the check valve operating state during drilling, (b) during injection, and (c) is an explanatory diagram of the boring bit.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is an explanatory diagram of an injection plant facility using a ground solution improvement chemical injection pipe according to an embodiment. As shown in FIG. 1, one set of injection equipment is provided on the transport vehicle 10.

  The injection facility has a power supply function (power generator 12 and switchboard 14) that generates power and supplies power, and a chemical preparation function (mixer and storage) that prevents primary storage and sedimentation by feeding and mixing materials and water to the mixer. (Liquid / water tank 16, water pump 18, gear pump) and pumping water during boring and main agent / hardener during injection, and liquid switching function (infusion pump 20, shunt, suction, delivery hose) And a flow meter 22 having a management function for digitally displaying the injection amount and the injection pressure from time to time and recording them on a chart paper as a graph. Water is conveyed from a water supply or water supply vehicle 24 and material is conveyed using a transport vehicle 26. The water supply vehicle 24 is used when tap water or river water cannot be used.

  As a boring function, a swivel 58, an injection pipe (consisting of an inner pipe body 30 and an outer pipe body 32), a monitor 34, and a boring bit (metal crown) 36, which will be described later, are mounted on the boring machine 28, and an infusion pump is used. Drilling and installing hydraulically to a predetermined depth while feeding water. At the time of injection, the inner tube 30, the outer tube 32, and the boring bit 36 can be stepped up or stepped down hydraulically after pressurizing a predetermined chemical solution.

[Roles of main equipment]
・ Mixer: The chemical solution requires a “main agent” and a “curing agent”, which are mixed with fresh water in separate mixers and used to maintain a liquid state without precipitation. The setting time (gel time) can be changed by changing the blending amount of the main agent and the curing agent. The consolidation time varies depending on the permeability of the ground.

Injection pump 20: Used to pump clear water (drilling water) when boring the ground, and to send out "main agent" and "hardener" when injecting chemicals.
The main agent and the curing agent are sent separately, mixed in the monitor 34 and consolidated in the ground.

  ・ Boring machine 28: After installing equipment such as an injection pipe, monitor 34, and metal crown (boring bit 36), while applying hydrostatic water to the rod while rotating the rod and applying penetration pressure (supply pressure) to the ground It is a machine that "bores" the ground by rotating excavation with a metal crown tip bit.

  Swivel (water swivel) 58: A swivel (water swivel) 58 is mounted between the rotating rod and the injection hose, and the hose is not twisted even if the rod rotates, and liquid is passed using a rotary joint.

  Rod: An injection tube having the following double tube structure (inner tube body 30 and outer tube body 32) is used for the rod. The rod is a pipe that pumps and discharges fresh water (drilling water) to the tip monitor 34 during boring, and is installed at a predetermined depth. Subsequently, the curing agent is used for pumping and discharging into the ground. That is, it is used for both drilling and injection.

Monitor 34: “Drilling water” or “seal solution” sent from the double pipe, and switching the flow path of “main agent” and “curing agent” or mixing “main agent” and “curing agent” uniformly Used to discharge into the ground after mixing and reacting.
Drilling water: When drilling, the gap is discharged to the ground to cool the rod and prevent wear.

  Below, the structure of the chemical | medical solution injection tube for ground improvement which concerns on embodiment is demonstrated.

  Explanatory views of the ground solution improvement chemical injection pipe according to the first embodiment of the present invention are shown in FIG. 2 to FIG. 11, and explanatory views of the ground improvement chemical liquid injection pipe according to the second embodiment are shown in FIG. Shown in

  As shown in FIG. 1, the ground improvement chemical injection pipe according to the first embodiment includes an outer tube body 32 provided with a plurality of peripheral surface discharge holes (strainer holes 40...) Around the outer tube body 32, and the outer tube body 32. And an inner tube body 30 provided with a side discharge hole 46 at least in the lateral direction at the distal end.

  In the chemical injection pipe for ground improvement, the outer pipe body 32 is an outer pipe having a configuration in which an end portion 38a of one outer pipe member 38 is inserted into and joined to an end portion 38a of the other outer pipe member 38. A joined body of the members 38, 38, and the end portion 38a of the one outer tube member 38 and the end portion 38a of the other outer tube member 38 are connected to the corresponding portions from the inside of the outer tube body 32 to the outside. The strainer hole 40 is formed, and the strainer hole 40 is normally closed between the ends of the one and the other outer tube members 38. When the internal pressure of the outer tube body 32 is higher than the external pressure, the strainer hole 40 is formed. An opening valve member 42 is mounted.

  Therefore, the outer tubular body 32 and the inner tubular body 30 are inserted into the ground by boring, and the valve member 42 is closed at the time of drilling where the pressure of the inner tubular body 30 is not applied so much or before the medicine is injected. Therefore, even if the pressure in the ground is high, earth and sand and muddy water do not enter the outer tube body 32 from the strainer hole 40, and there is no obstacle to moving the inner tube body 30 up and down.

  Further, by applying pressure in the inner tube body 30, the valve member 42 of the strainer hole 40 is opened, and the seal grout and the chemical solution can be sufficiently injected into the ground.

  A monitor 34 is provided at the tip of the inner tube 30. A plurality of seal members 44 are provided on the side surface of the monitor 34 so as to be slidably in close contact with the inner surface of the outer tube body 32 at a distance from each other. A side discharge hole 46 is provided in the side direction.

  A pressurized chemical solution is introduced into the inner tube body 30 when the chemical solution is injected, and the chemical solution is discharged from the side surface discharge hole 46 so that the internal pressure in the outer tube body 32 between the seal members (for example, O-rings) 44 and 44 is increased. And the valve member 42 of the strainer hole 40 is opened so that the chemical solution is injected from the strainer hole 40 into the ground around the outside of the outer tubular body 32.

  When the drilling bit 36 is provided at the distal end of the outer tubular body 32 and the drilling water is fed when drilling by rotating the outer tubular body 32, the distal end opening of the inner tubular body 30 (second discharge hole 50). The check valve 74 is opened from the discharge hole 48 of the outer tubular body 32, and the drilling water is mainly discharged from the discharge hole 48. With respect to the strainer hole 40, the valve member 42 is not opened and the drilling water is discharged from the strainer hole 40. Does not come out. Therefore, the drilling water is concentrated on the boring bit 36 to make a smooth drilling, and the drilling water is not wasted.

Each part will be described.
A distal end discharge hole 48 opening in the forward direction and a boring bit 36 having a distal end serving as a drilling edge are provided at the distal end portion of the outer tube body 32, and a function of a flow path for passing the drilled water is provided therein.

  In addition, the monitor 34 at the distal end portion of the inner tube body 30 is provided with a second discharge hole 50 opening forward and a valve body (for example, a steel ball) 52 having a structure capable of closing the second discharge hole 50. Provided.

  The outer tube body 32 and the inner tube body 30 are provided with a locking structure 54 in the swivel sub 56 that is relatively fixed in the rotational direction when drilling.

  Specifically, as shown in FIGS. 2 to 5, the outer tube body 32 has an outer periphery of an end portion 38 a of one outer tube member 38 having an undercut shape and a male screw 38 b formed on the outer peripheral surface thereof. And the valve member 42 which consists of an elastic material which covers the strainer hole 40 is provided in this outer peripheral surface. As the valve member 42, a band-shaped or belt-shaped elastic material valve member that surrounds the end 38 a of the outer tube member 38 and covers the strainer hole 40 may be used. The outer tube body 32 is used by adding a plurality of the same ones to a length corresponding to the drilling distance. FIG. 4 shows one of the outer tube bodies 32 to be connected, and FIG. 5 shows the details of the connected portions.

  A male screw 38b is formed by an external screw structure near the stepped portion of the outer peripheral surface having a small diameter of the end portion 38a, and an end surface side (front side) strainer hole 40 is further drilled. The valve member 42 is made of a band-like elastic material (made of rubber or elastomer) so as to be wrapped from the outside so as to be opened and closed.

  In addition, a strainer hole 40 is formed in the vicinity of the step portion where the inner periphery of the end portion 38a of the other outer pipe member 38 is expanded stepwise, and an inner screw is formed on the inner peripheral surface on the end surface side (rear side). Thus, a female screw 38c is formed (see FIG. 4).

  As shown in FIG. 5, in the structure of the outer tube body 32, a plurality of outer tube members 38, 38 are screwed together, and the male screw 38 b at the end 38 a of one outer tube member 38 is replaced with another outer tube member. The one and other outer tube members 38, 38 are connected to each other by screwing into the female screw 38c of the end portion 38a of 38, and the strainer holes 40 of these one and other outer tube members 38, 38 are formed. The valve member 42 is sandwiched between the end portions 38a and 38a. The valve member 42 is sandwiched between the end portions 38a, 38a of the outer tube members 38, 38 by protecting the valve member 42 between the ends of the one and the other outer tube members 38, 38. Therefore, the earth and sand in the ground located at a predetermined depth does not hit the valve member 42 and can be prevented from being damaged. Further, if the outer pipe members 38 are removed, the valve member 42 can be exposed and easily replaced, so that maintainability can be improved.

Further, as shown in FIG. 6, the outer tube body 32 and the inner tube body 30 are assembled at the time of work, are set up in the up-down direction so that the lower end is directed to the ground, and a swivel 58 is provided at the upper end and suspended.
The locking structure 54 for fixing in the rotational direction relatively at the time of drilling is a rotation stop groove on the inner side of one outer tube body 32 at a position corresponding to the time of drilling at the upper ends of the outer tube body 32 and the inner tube body 30. 54a is formed, and on the other side, a rotation stop projection 54b is formed outside the inner tube 30. In addition to the above, the locking structure 54 of the rotation stopper may be formed with a protrusion inside the outer tube 32 and a groove outside the inner tube 30.

  Further, the swivel sub 56 is fixed to the outer tube body 32 at the upper end, and is engaged with the swivel 58. The swivel 58 is liquid-tightly attached to the upper end of the inner tube body 30, and a hose from the infusion pump 18 is connected thereto. The inner tube 30 can be pumped with static water at the time of drilling, a sealing material at the time of sealing, and a main agent / curing agent at the time of injection of the chemical solution.

  Specifically, the suspension fitting 56a is fixed to the outer surface of the swivel sub 56 by welding or the like so as to correspond to the portion where the rotation stopper groove 54a is formed on the inner surface of the outer tube member 38A at the upper end of the outer tube body 32. Has been. The upper end of the inner tube body 30 is connected to the swivel 58, but a receiving bar 60 is projected in the horizontal direction on the outer surface of the inner tube body 30 provided below the swivel 58 so that the rod body portion Then, it is engaged with the notch 56b of the hanging metal fitting 56a. As shown in FIG. 6 (b), the notch 56b is opened in the left rotation direction when viewed from above, and rotates the outer tubular body 32 counterclockwise by about 20 degrees (in top view) with respect to the inner tubular body 30. Then, the support bar 60 fits into the notch 56b, and conversely, if the outer tube 32 is rotated to the right by approximately 20 degrees or more (in top view) with respect to the inner tube 30, the support bar 60 is notched 56b. The inner tube 30 can be detached from the outer tube 32 by being detached from the outer tube 32.

The support bar 60 and the suspension fitting 56a have the following functions while improving workability by suspending the outer tubular body 32.
Since the inner tube 30 and the outer tube 32 move separately, the one-touch operation cannot be performed because the inner tube 30 and the outer tube 32 are moved separately, so that it takes time and effort to support the outer tube 32 both during attachment and detachment. Reduce.
As a method for improving this situation, the inner tube 30 on the side connected to the inner tube 30 already mounted on the boring machine 28 is placed and rotated to the right. At this time, the outer tube 32 on the connecting side is a hanging bracket. 56a and the suspension rod 60 can be rotated to the right, and the inner tube 30 is also integrated so that it can be rotated in the same direction and screwed into the inner tube 30 on the boring machine 28 side with one touch. become.
Subsequently, the suspension fitting 56a can be rotated 20 degrees counterclockwise from the receiving rod 60 to be removed from the receiving rod 60 and connected to the outer tubular body 32 on the boring machine 28 side.
When the inner tube body 30 and the outer tube body 32 are removed after the injection is completed, the inner tube body 30 can be easily removed in a state where the outer tube body 32 is detached and suspended from the receiving rod 60.

[Double pipe structure of inner tube 30]
Here, as shown in FIGS. 2 to 3, the inner tube body 30 of the chemical liquid injection tube according to the embodiment has an inner / outer duplex structure in which a second inner tube body 64 is provided outside the first inner tube body 62. It is a tube structure. In the inner tube 30, a space in the first inner tube 62 is defined as a first passage 66, and a space between the outer peripheral surface of the first inner tube 62 and the inner peripheral surface of the second inner tube 64. Is a second passage 68, and the liquid can be individually sent to the first passage 66 and the second passage 68 from the swivel 58. As will be described later, the main agent and the hardener flow into the swivel 58 via another hose. In the present invention, the inner tube 30 uses a single tube at the time of drilling or a long gel time chemical injection (single phase injection), and uses a different gel time chemical solution (multiphase injection). A heavy pipe may be used. The inner tube 30 may be a triple tube or a multiple tube other than a double tube.

[Monitor 34]
The tip of the inner tube 30 is provided with a monitor 34 for mixing and mixing the liquid sent through the first passage 66 and the second passage 68 in the internal space. Lateral side discharge holes 46 communicating from the inside of the monitor 34 to the side surface are provided at positions within the interval between a plurality of sealing members (a pair of spaced O-rings) 44, 44 provided at intervals later. It has a structure.

  The main agent is sent to one of the first passage 66 and the second passage 68, and the curing agent is sent to the other. The monitor 34 at the tip of the inner tube 30 has the first passage and the second passage 68. A side surface discharge hole in a lateral direction at a position within an interval between a plurality of seal members 44, 44 provided on the side surface of the monitor 34, where the chemical liquid composed of the main agent and the curing agent fed through the passage is merged and mixed in the internal space. The mixed chemical solution is discharged from 46 toward the strainer hole 40 of the outer tube body 32.

  The monitor 34 has a structure in which a side discharge hole 46 in a lateral direction communicating from the inside of the monitor 34 to the side surface is provided at a position within the interval between a plurality of seal members 44, 44 provided at intervals later. Therefore, since the chemical solution is sent to the tip of the injection tube by the monitor 34, it can be mixed, so there is a problem of gel time as in the conventional method of mixing before entering the inner tube 30 to be injected. It does not occur. Therefore, the chemical solution can be selected without considering the gel time at the time of mixing the chemical solution, and the most appropriate chemical solution can be selected and injected into the ground.

[Valve 52 of Second Discharge Hole 50]
In the monitor 34, the structure capable of closing the second discharge hole 50 is larger in diameter than the inner diameter of the second discharge hole 50 in the first embodiment (first construction mode), and is downward. A valve body 52, specifically, a steel ball, falls inside the inner tube body 30 facing the other end by its own weight and fits into the second discharge hole 50. When the valve body 52 is mounted, the swivel 58 is removed from the rear end of the inner tube body 30, the valve body 52 is dropped into the inner tube body 30 from the rear end opened upward, and the second discharge hole 50 is formed by a simple procedure. It can be closed (see the state in FIG. 9).

  In this way, the second discharge hole 50 at the front end of the inner tube body 30 is opened and the valve body 52 having a simple structure capable of closing the second discharge hole 50 is provided. The drilling water is discharged from the second discharge hole 50 and smoothly drilled by the boring bit 36. On the other hand, when the chemical solution is injected, the second discharge hole 50 is closed by the valve body 52 to ensure that the chemical solution is grounded. Can be injected. Further, since the valve body 52 is dropped by its own weight in the inner tube body 30 facing forward and fitted into the second discharge hole 50, the valve body 52 has a simple structure and is highly economical. Because it is a steel ball, it is robust and reusable and maintenance-free.

[Check valve 74 of outer tube 32]
Further, a check valve 74 is provided in the distal end discharge hole 48 of the outer tubular body 32 (see FIGS. 2 and 9). Drilling water is supplied at the time of drilling (during boring) in which a boring bit (metal crown) 36 rotated by rotating the outer tube 32 together with the inner tube 30 is pushed to the ground. At this time, the check valve 74 opens the tip discharge hole 48 with the pressure of the above-mentioned drilling water to supply the drilling water to the boring bit 36, while when the drilling water is not pumped, It has a function of blocking the permeated water in the ground from flowing into the outer tube body 32 and the inner tube body 30 from the tip discharge hole 48 by the pressure.

  Specifically, in the check valve 74, a resin or metal valve body 74a is urged by a spring member 74b from the front toward the rear with respect to the tip discharge hole 48 to be pressed by the tip discharge hole 48. The urging force of the spring member 74b of the check valve 74 is set so as to be opened by the water supply pressure of the drilling water during drilling.

  Therefore, a check valve 74 is opened at the tip discharge hole 48 at the tip of the outer tube 32 by the pressure of the drill water supplied when drilling by the boring bit 36, and shuts off the flow into the tip discharge hole from the outside. Since it is provided, earth and sand can be prevented from flowing into the outer tubular body 32 from the boring bit 36, and workability can be prevented from being lowered.

The procedure of the ground improvement construction method using the chemical injection pipe for ground improvement according to the first embodiment (first construction form) will be described.
As shown in FIG. 7, an outer tube monitor (a lower end for connection of the outer tube member 38) and a boring bit (metal crown) 36 are attached to the lower end of the outer tube body 32, and a monitor 34 is attached to the lower end of the inner tube body 30. The inner tube 30 is inserted into the outer tube 32.

  As shown in FIG. 2, the inner tube body 30 and the outer tube body 32 are attached to the boring machine 28, and the drilling water is fed by the injection pump 20 through the swivel 58 attached to the upper ends thereof.

  As shown in FIG. 7, the drilling water enters the inner tube 30 and the monitor 34 at the lower end of the inner tube 30 from the swivel 58, opens the check valve 74 with the pressure of the drilling water, and the check The valve 74 discharges through the boring bit 36 into the ground. At the same time, the boring machine 28 rotates the outer tube 32 and rotationally drives the boring bit 36, so that the ground is drilled. As shown in FIG. 7, the drilling water passes between the outer tubular body 32 and the ground hole and comes out to the ground surface 76 together with the gap.

  In this case, according to the drilling depth, the inner tube body 30 and the outer tube body 32 are added and drilled to a predetermined depth.

  The boring procedure of the inner tube body 30 and the outer tube body 32 will be described with reference to FIG.

  As shown in FIG. 11A, at the time of drilling preparation / starting drilling, the boring machine 28 is installed, the monitor 34, the inner tube body 30, the outer tube body 32, and the swivel 58 are mounted, and boring is started.

  When no further drilling is possible due to the length of the inner tube 30 and the outer tube 32 that are initially installed, the boring machine 28 is stopped, the swivel 58 is removed, and as shown in FIG. The swivel sub 56 is added (the suspension fitting 56a is engaged with the notch 56b and hung), and the connection portion of the inner tubular body 30 is added to the swivel sub 56. Then, as shown in FIG. 11C, the outer tube body 32 is added to the swivel sub 56. The outer tube body 32 extends by extending the outer tube member 38.

  Then, as shown in FIG. 11 (d), the inner tube 30 added to the swivel 58 is connected to the inner tube 30 on the boring machine 28 side.

  Next, as shown in FIG. 11 (e), the suspension fitting 56 a of the swivel sub 56 is removed from the notch 56 b, and the outer tube member 38 connected to the swivel sub 56 is connected to the outer tube body 32. In this connection, the strainer hole 40 is aligned. When the locking structure 54 (rotation prevention protrusion 54b, rotation prevention groove 54a) is engaged and the inner tube body 30 and the outer tube body 32 are rotated in the same rotation direction by the boring machine 28, both are simultaneously rotated. I try to bowl.

[Injection of sealant]
The seal injection can be started by switching the injection pump 20 from the drilling water to the sealing chemical while the drilling is completed, and can be injected from the strainer hole 40 in accordance with the sealing situation.
Then, as shown in FIG. 9, the valve body 52 is dropped to close the second discharge hole 50, and the main agent of the sealing chemical solution is transferred from the first passage 66 and the second passage 68 in the inner tube body 30. A curing agent is injected (if the same liquid is acceptable, the same liquid is injected into the passages 66 and 68), and discharged from the side discharge hole 46 between the seal members 44, 44 into the outer tube body 32.
At this time, the pressure is applied to the check valve 74 at the tip of the outer tube body 32 from the second discharge hole 50 only slightly, so that the check valve 74 is closed, and the sealing agent discharged from the side surface discharge hole 46 into the outer tube body 32 is blocked. Since the pressure is strong, the valve member 42 of the strainer hole 40 of the outer tubular body 32 is opened, and the seal chemical can be injected into the ground. The position of the side surface discharge hole 46 of the inner tube body 30 is sequentially adjusted to the strainer hole 40 from below, and the inner tube body 30 is pulled out, the valve member 42 of each strainer hole 40 is opened sequentially, and the sealant is put into the ground. inject.
Seal injection starts from the lowest end, and is injected while pulling the inner tube 30 to the upper end of the improved range, and fills the space outside the outer tube 32.

  Further, in the embodiment, the outer tube members 38 constituting the outer tube body 32 have an outer diameter of 40.5 mm and are each formed with a length of 50 cm. Therefore, the distance between the strainer holes 40 is 50 cm (the lengths of the end portions 38 a overlap), and the injection of the sealant into the ground is 50 cm. The length of the outer tubular body 32 is an example, and the length can be set according to the construction.

The injection range is a range indicated by a broken line in FIG.
[Chemical solution injection procedure]
As shown in FIG. 10, in the state where the valve body 52 is dropped and the second discharge hole 50 is closed, the ground improver chemical solution is placed in each of the first passage 66 and the second passage 68 in the inner tube body 30. The main agent and the curing agent are injected (if the same solution is acceptable, the same solution is injected into the passages 66 and 68), and mixed in the monitor 34, and then the outer tube body from the side discharge hole 46 between the seal members 44, 44. 32 is discharged.

  At this time, since the pressure is applied only minutely from the second discharge hole 50 to the check valve 74 at the tip of the outer tube body 32, the pressure is applied to the check valve 74, so that the improvement material chemical solution is discharged into the outer tube body 32 from the side surface discharge hole 46. Therefore, the valve member 42 of the strainer hole 40 of the outer tube 32 is opened, so that the chemical solution of the ground improvement agent can be injected into the ground.

  The inner tube body 30 is gradually lowered from the uppermost stage of the improved range, close to the ground surface 76, and the position of the side discharge hole 46 is sequentially adjusted to the strainer hole 40, and the inner tube body 30 is gradually lowered to the lowermost stage. The valve member 42 of the strainer hole 40 is opened, and the chemical liquid of the ground improvement material is injected into the ground.

  In the embodiment, the outer tube members 38 constituting the outer tube body 32 are each formed with a length of 50 cm. Therefore, the space | interval of the strainer hole 40 is about 50 cm space | interval, and injection | pouring of a ground improvement agent chemical | medical solution in the ground is 50 cm space | interval.

  Next, the chemical solution injection tube according to the second embodiment (second construction mode) will be described.

  As shown in FIG. 12, the chemical injection pipe is provided with a boring bit 36 at the distal end portion of the outer tube body 32 and has a second discharge hole 50 opened in the forward direction at the distal end portion of the monitor 34. As in the first embodiment, the front end of the first inner tube 62 is moved into the monitor 34 instead of the valve body 52 in the monitor 34, and the second end of the monitor 34 is moved. A movable valve 78 capable of opening and closing the discharge hole 50 is provided. (A) is an assembly view in which the movable valve 78 in the drilled state is retracted, and (c) is an exploded view in which the movable valve 78 in the injection state is advanced.

  The movable valve 78 is a hollow body whose front surface and rear surface are closed, a communication hole 78a is formed in the front side surface and the rear side surface, and a seal member 78b that is in sliding contact with the inside of the monitor 34 is formed on the peripheral surface. Provided, the entire movable valve is repelled rearward by an elastic body (not shown) such as a spring. Further, the movable valve 78 can open and close the second discharge hole 50 at its front end, and comes into contact with and disengages from the front end opening of the first inner tube body 62 at the rear end. 66 can be closed and opened.

Similar to the first embodiment, the inner tube 30 has a double tube structure including a first inner tube 62 and a second inner tube 64. The monitor 34 is attached to the tip of the second inner tube body 64, has a side discharge hole 46, and a seal member 44 is provided before and after the side discharge hole 46.
Further, the seal members 78b to 78b on the side surface of the movable valve 78 are provided at three locations, that is, the rear portion, the center portion, and the tip portion, and the rear seal member 78b is provided at a front position close to the rear communication hole 78a. In addition, a central seal member 78b and a front end seal member 78b are provided at intervals before and after the front communication hole 78a. The outer periphery of the seal members 78b and 78b at the rear and center is sealed to the inner surface of the monitor 34, and the seal member 78b at the tip is formed with an outer diameter that can seal the second discharge hole 50.

As shown in FIG. 13, when the outer tube 32 is rotated and the boring bit 36 is drilled, the monitor 34 urges the movable valve 78 backward by an elastic body (not shown) to urge the inner tube body. The first passage 66 in 62 is closed. As described above, in the state where the first passage 66 is closed by the movable valve 78, the drilling water is caused to flow into the second passage 68 in the inner tube 30 at a predetermined pressure. Although the hydraulic pressure is applied to the second passage 68, no hydraulic pressure is applied to the first passage 66. That is, no forward pressure is applied to the movable valve 78, and the first passage 66 is closed. maintain. Thus, the movable valve 78 remains at the initial position.
At this time, the rear part and the central part of the seal members 78b to 78b on the side surface of the movable valve 78 are located between the second passage 68 and the side discharge hole 46 and block communication therebetween. A second passage 68 communicates with the rear communication hole 78a from the rear of the seal member 78b, and the drilling fluid passes from the front communication hole 78a through the hollow inside of the movable valve 78 to the outer periphery of the seal member 78b at the front end. And the inner surface of the monitor 34, and is supplied from the second discharge hole 50 toward the boring bit 36. Drilling water around the boring bit 36 passes between the outer tube 32 and the ground hole and is discharged to the ground surface 76.

  As shown in FIG. 14, at the time of injection of the sealing agent, the main force and the curing agent of the sealing chemical solution are applied to the first passage 66 and the second passage 68 while applying pressure to the elastic force of the projectile. The movable valve 78 is driven and pushed down. As a result, the first passage 66 is opened and the second discharge hole 50 is closed. Since the first passage 66 and the second passage 68 communicate with each other behind the movable valve 78, the main agent and the curing agent are mixed in the monitor 34 (at this time, the hollow of the movable valve 78 and the communication hole 78a are in the monitor). 34 is closed by a sealing member 78b). The sealing chemical liquid mixed from the side-facing side discharge hole 46 is supplied to the space between the hole wall and the outer periphery of the outer tube 32 and the cavity in the ground via the strainer hole 40 of the outer tube 32. The inner tube body 30 is pulled up sequentially from below, and a sealant is injected into a cavity or the like in the ground at each step.

  After injection of the sealing agent, as shown in FIG. 15, the ground improvement chemical solution is injected. The movable valve 78 is driven to open the first passage 66 and the second discharge hole by causing the chemical main agent and the curing agent to flow through the first passage 66 and the second passage 68 under pressure. 50 is closed, the main agent and the curing agent are mixed in the monitor 34, and the chemical solution mixed from the side discharge hole 46 facing the side is supplied into the ground via the strainer hole 40 of the outer tube body 32. The inner tube body 30 is sequentially lowered from the top in a stepwise manner, and injection is performed for each step.

  According to the second embodiment, the entire movable valve 78 is elastically ejected rearward by the elastic body, the second discharge hole 50 can be closed at the front end portion, and the first at the rear end portion. By being configured to be able to close the distal end opening of the inner tube body 62, the closing structure of the second discharge hole 50 can be controlled by the liquid injection pressure into the inner tube, and a separate valve member is mounted. Because it is not necessary, it is easy to use. Moreover, the injection of the chemical solution can be appropriately performed without requiring a complicated control device.

Next, a third embodiment (third construction mode) of the present invention will be described.
FIG. 16 is an assembly diagram of the ground improvement chemical injection pipe according to the third embodiment, and is an explanatory view of a drilling procedure using the ground improvement chemical injection pipe. Moreover, FIG. 17 is explanatory drawing of the sealing procedure (seal injection | pouring / hardening agent injection | pouring) using the chemical | medical solution injection tube for the ground improvement. FIG. 18 is an assembly diagram of a monitor constituting the chemical solution injection pipe for ground improvement. FIG. 19 is an exploded view of the monitor. FIGS. 20A and 20B are explanatory views of the monitor outer tube, in which FIG. 20A is a longitudinal sectional view and FIG. 20B is a sectional view taken along line AA ′ in FIG. FIG. 21 is a longitudinal sectional view of the check valve and the boring bit. (A) shows the check valve operating state during drilling, (b) during injection, and (c) shows the boring bit. It is explanatory drawing.

  As shown in FIG. 16, the ground improvement chemical liquid injection tube according to the third embodiment is provided with a boring bit 36 at the distal end portion of the outer tubular body 32, and moves forward and backward in the monitor 34 to perform the second discharge. A valve body 52 that can open and close the hole and a spring 84 that biases the valve body 52 forward are provided.

The structure of the monitor 34 will be described.
As shown in FIG. 18, the monitor 34 includes a monitor inner tube 34 b connected to the tip of the inner tube 30 of the injection tube and a monitor outer tube 34 a connected to the tip of the outer tube 32. . A cross valve seat 34e is built in the tip (lower end) of the monitor outer tube 34a, and the inner tube 34b is a valve in the monitor inner tube 34d in addition to the monitor inner / outer tube 34c and the monitor inner tube 34d. A body 52 and a spring 84 that moves the valve body 52 up and down are loaded.

  A sealant and a curing agent are guided to the strainer hole 40 of the outer tube body 32 on the outer surface of the monitor inner outer tube 34 c, and a drilling water sealant and a curing agent are placed in the gap between the outer tube body 32 and the inner tube body 30. A sealing member 44 made of an O (O) ring that prevents leakage is mounted in two stages above and below the side surface discharge hole 46.

Further, on the inner surface of the monitor inner outer tube 34c, a spring receiver 80 for receiving the rear end of the spring 84 is disposed and fixed behind the side discharge hole 46 in the lateral direction, and the spring 84 received by the spring receiver 80 is provided. The valve body 52 is urged forward. Further, a ring valve seat 82 is disposed and fixed at a position ahead of the inner surface side discharge hole 46 of the monitor inner outer tube 34c, and a seal made of an O (O) ring for leak-sealing the rear surface of the ring valve seat 82. The body 44a is mounted, and the second discharge hole 50 is configured to be in close contact with the ring valve seat 82 by the biasing force of the spring 84 when the valve body 52 is positioned forward in the monitor inner / outer pipe 34c. Has been.
As shown in FIGS. 18 and 20, the monitor outer tube 34 a has a strainer hole 40 formed in the female screw portion at the rear thereof, and is screwed into the male screw at the distal end portion of the outer tube body 32, so that the strainer holes 40 are connected to each other. To match. The monitor outer tube 34a is fixed to the outer tube body 32, and a female screw is formed at the front end portion of the monitor outer tube 34a at the tip of the cross valve seat 34e. The cross valve seat 34e is a receiving valve seat in which a plurality of arm portions spaced from each other from the inner wall of the monitor outer tube 34a extend to the center of the shaft. Even when the valve body 52 hits, the cross valve seat 34e is between the valve seat 52e and the valve seat 34e. The liquid can be passed through.

  As shown in FIG. 21, the check valve 74 is provided with a valve body 74a and a spring member 74b in a portion where the rear portion of the outer peripheral main body has a small diameter, and a male screw is formed on the outer peripheral surface. A male screw is screwed and fixed to a female screw at the tip of the monitor outer tube 34a. A male screw at the rear part of the boring bit 36 is screwed and fixed to a female screw at the inner periphery of the outer end of the outer peripheral body of the check valve 74.

As shown in FIG. 19 , the valve body 52 is provided with a top plate 52a and a lower plate 52b on the front side with the valve rod 52c interposed therebetween, and the front surface (lower surface) of the top plate 52a is in close contact with the ring valve seat 82. The water tightness can be maintained. As shown in FIG. 19 , the spring 84 is preferably a spiral metal spring. Further, the inner and outer tubes 34c of the monitor inner tube 34b are fixed to the distal end of the second inner tube body 64 outside the inner tube body 30 of the monitor by screwing, welding or the like. Further, the inner inner tube 34d of the inner tube 34b is connected to the tip of the first inner tube 62 inside the inner tube 30 to ensure the flow of the liquid into the monitor 34 and the mixing of the liquids. However, it is not necessary.

  As described above, when the ring valve seat 82 is provided on the inner peripheral surface of the monitor inner outer tube 34c at a position ahead of the side discharge hole 46 in the lateral direction, and the valve body 52 is positioned on the front side in the monitor 34. Due to the urging force of the spring 84, the valve body 52 comes into close contact with the ring valve seat 82 and the second discharge hole 50 is closed, and at the same time, a boring bit mounting portion (monitor outer tube 34a) at the tip of the outer tube body 32. A cross valve seat (contact portion) 34e is provided on the inner side of the main body of the check valve 74, and the valve body 52 contacts the cross valve seat 34e and resists the urging force of the spring 84. When the valve 52 is moved rearward in the monitor 34, the valve body 52 is separated from the ring valve seat 82 and the close contact is released, whereby the second discharge hole 50 is opened.

  As shown in FIG. 16, the outer tube 32 and the inner tube are arranged upstream of the monitor 34 (the monitor outer tube 34a and the monitor inner tube 34b) during the operation using the ground improvement chemical injection pipe according to the third embodiment. The body 30 is connected, and the swivel 58 and swivel sub 56 shown in FIG. 6 and the injection equipment shown in FIG. 1 are connected to the end of the body 30, and a check valve 74 and a boring bit 36 are attached to the lower part of the monitor 34. It is configured to be capable of drilling.

(1) The operation will be described.
The case of injecting the seal from the drilling hole will be described with reference to FIGS.

[A] At the time of drilling At the time of drilling, as shown in FIG. 16, the inner tube body 30 is moved forward (downward), and the monitor tube 34a provided at the distal end portion of the outer tube body 32 is placed in the monitor. Tube 34b is positioned. The side surface discharge hole 46 is closed in close contact with a plurality of seal members 44 and the inner peripheral surface of the monitor outer tube 34a, and the valve body 52 in the monitor 34 is connected to the cross valve seat (contact portion) 34e. Make contact. Thus, the valve body 52 is pushed up and moved rearward from the ring valve seat 82 to open the second discharge hole 50.
Drilling water is pumped to the first passage 66 and the second passage 68 of the inner tube 30. The drilling water flowing down the passages 66 and 68 can reach the second discharge hole 50 of the monitor 34 and the cross valve seat 34e. Further, when the pressure of the drilling water increases, the check valve 74 is pushed down, and it is in a state where it can flow down in the boring bit 36 and be discharged into the ground. That is, it is in a state where drilling is possible.
At this time, since the tip of the side discharge hole 46 is closed by the inner wall of the monitor outer tube 34a and the seal members 44, 44, the drilling water does not leak in the direction of the strainer hole 40.

[B] Seal injection state The drilling completion state is a state in which seal injection is possible from the tip of the boring bit 36 at the same time as the drilling is completed.
When it is necessary to inject seal injection from an arbitrary strainer hole 40, as shown in FIG. 17, the inner tube body 30 is pulled up, the side discharge hole 46 of the monitor 34 is aligned with the strainer hole 40, and then the seal injection is continued. Is ready to continue. In this case, the valve body 52 is brought into close contact with the ring valve seat 82 by the biasing force of the spring 84 in the monitor 34, and the main agent of the chemical solution and the curing are set in the first passage 66 and the second passage 68 of the inner tube 30. The main agent and the curing agent are mixed in the monitor 34 by flowing the agent under pressure, and the chemical solution mixed from the side discharge hole 46 in the lateral direction is passed through the strainer hole 40 of the outer tube body 32 into the ground. Enable supply.

Since the above operation is possible, the operability and malfunction during drilling / injection are improved, maintenance is easy, and it can be used to reduce the cost of monitor production.
Further, after the injection is completed, it is possible to return to the state of drilling simply by pushing down the inner tube body 30, and it is possible to execute drilling, seal injection, and curing agent injection at any time reasonably and repeatedly.
It is also an important factor to enable this repetitive work in the injection work.

  (2) The drilling liquid injection procedure [A] to [D] will be described.

[A] Drilling The chemical injection pipe is set in the boring machine 28 in the state of drilling in FIG. 16, the piping to the injection facility in FIG. 1 is completed, and the injection pump 20 is operated.
At this time, since the valve body 52 is pushed down, the drilling water pushed out from the infusion pump 20 flows down to the check valve 74 and further feeds the drilling water to increase the water pressure, thereby increasing the check valve 74. Is opened, water is supplied to the tip of the boring bit 36, and the boring machine 28 is rotated and supplied with pressure to start boring.
Further, the boring is continued while the drilling water is supplied, and the strainer pipe (the outer pipe body 32, and the inner pipe body 30 if necessary) is drilled to a predetermined depth while being sequentially connected.

[B] Seal injection (drilled state)
Seal injection starts injection by switching the drilling water to a sealant when the drilling is completed.
When the seal injection is performed from the strainer hole 40 of an arbitrary outer tube 32 as necessary, the inner tube 30 and the monitor 34 are pulled up, and the side discharge holes 46 of the monitor 34 are continuously aligned with the position of the strainer hole 40. Then, seal injection is performed.
It is completed after confirming that the sealant has flowed out to the ground and the borehole has been filled with the sealant.

[C] Curing Agent Injection After confirming whether the side discharge hole 46 of the monitor 34 is aligned with the strainer hole 40 at the upper end of the injection range, the injection pump 20 is switched from the sealing agent to the curing agent, and injection is started.
Each time the injection for each step is completed, the side discharge hole 46 of the monitor 34 is stepped down to the strainer hole 40 immediately below, and the injection is continuously repeated to complete the injection in the lowermost injection range.

[D] Pull out strainer tube (outer tube body 32 and inner tube body 30) and inject hole filling After completion of the lowermost injection, push down the inner tube body 30 and press the monitor 34 against the cross valve seat 34e for drilling. Return to the state.

Subsequently, the injection pump 20 is switched from the curing agent to the hole filling agent, and the outer tube body 32 and the inner tube body 30 are pulled out while filling and filling the hole from the tip of the boring bit 36 to complete the entire process per injection hole.

  According to the ground improvement chemical injection pipe of the third embodiment, after completion of the injection pipe, the monitor 34 is pushed into the upper surface of the cross valve seat 34e to push up the valve body 52 to return to the state of drilling (FIG. 16). Then, the outer tube body 32, which is a strainer tube, is gradually pulled out and continuously returned to the state before the start of boring while continuously filling and injecting the hole.

Note that the conventional monitor described above is inefficient because the valve body remains, and therefore the hole filling material cannot be continuously discharged in the direction of the boring bit at the lower end. The present invention solves such problems.
That is, according to the present invention, in addition to facilitating the switching from the completion of boring to the seal injection, the switching from the completion of injection to the filling filling with holes is easy, and the merit of shortening the time is great.

  Conventionally, the monitor needs to be cleaned every time the injection per hole is completed. However, after the hole 20 is injected, the clean water is simply supplied from the pump 20 and no cleaning is required, thereby eliminating time loss.

The chemical injection pipe for ground improvement of the present invention can be used for various ground improvements such as flat land, hilly land, wet land and the like.
Further, not only the vertically downward direction but also 360 ° boring and chemical injection can be performed.

28 Boring machine 30 Inner tube 32 Outer tube 34 Monitor 34a Monitor outer tube (applicable to the third construction mode)
34b Monitor inner pipe (applicable to the third construction mode)
34c Monitor inner and outer pipes (applicable to the third construction mode)
34d Internal pipe of the monitor (applicable to the third construction mode)
34e Cross valve seat (applicable to the third construction mode)
36 Boring bit 38 Outer tube member 38a Upper and lower end portions 38b of outer tube member Male screw 38c of outer tube member Female screw 38A Outer tube member (outer tube of swivel sub)
40 Strainer hole 42 Valve member 44 Seal member (located on the side of the monitor)
44a Seal body 46 Side discharge hole (formed on the monitor side wall)
48 Discharge hole 50 at outer tube end Second discharge hole (monitor end)
52 Valve body (for closing the monitor tip: applied to the first construction mode)
52a Top plate of valve body (applicable to the third construction mode)
52b Bottom plate of valve body (applied to the third construction mode)
52c Valve body valve stem (applied to the third construction mode)
54 Locking structure 54a Locking structure groove 54b Locking structure protrusion 56 Swivel sub 56a Suspension bracket 56b Notch 58 Swivel 60 Retaining bar 62 First inner tube (inner side)
64 Second inner tube (outside)
66 First passage 68 Second passage 74 Check valve 74a Check valve body 74b Spring member 76 of check valve Ground surface 78 Movable valve (applied to the second construction mode)
78a Movable valve communication hole (applicable to the second construction mode)
78b Movable valve seal member (applicable to the second construction mode)
82 Ring valve seat (applicable to the third construction mode)
84 Spring (Applicable to the third construction mode)

Claims (9)

A ground improvement chemical solution having an outer tube body provided with a plurality of peripheral surface discharge holes in the periphery, and an inner tube body inserted into the outer tube body and provided with a side discharge hole at least in the lateral direction at the tip. In the injection tube,
The outer tube body is a joined body of outer tube members having a configuration in which an end portion of one outer tube member is inserted and joined into an end portion of the other outer tube member,
A strainer hole communicating from the inside of the outer tube body to the outside is formed at the corresponding portion at the end of one outer tube member and the end of the other outer tube member in the coupled state, and one and the other outer tube members A valve member that normally closes the strainer hole between the ends of the tube and opens the strainer hole when the internal pressure of the outer tube is higher than the external pressure,
Provided on the side surface of the distal end portion of the inner tube body are a plurality of seal members that are slidably in close contact with the inner surface of the outer tube body at a distance from each other. A side-facing side discharge hole that communicates with the side surface is provided,
When a pressurized chemical solution is introduced into the inner tube during the injection of the chemical solution, the drug solution is discharged from the side discharge holes to increase the internal pressure in the outer tube between the seal members, and the valve member of the strainer hole is opened. The chemical solution is injected from the strainer hole into the surrounding ground outside the outer tube body ,
At the tip of the outer tube body, a tip discharge hole that opens forward and a boring bit are provided,
The distal end portion of the inner tube body is provided with a second discharge hole that opens forward and a structure capable of closing the second discharge hole,
The outer tube and the inner tube are provided with a locking structure that is fixed in the rotational direction relatively when drilling,
The locking structure for fixing in the rotational direction relatively at the time of drilling is formed with a rotation stop projection on one side and a rotation stop groove on the other side at a position corresponding to the time of drilling the outer tube and the inner tube. A chemical solution injection pipe for ground improvement characterized by being a thing. The outer tube body has a male screw formed on the outer peripheral surface of the end portion of one outer tube member, and a valve member made of an elastic material covering the strainer hole is provided on the outer peripheral surface, and the end of the other outer tube member is provided. A female screw is formed on the inner peripheral surface of the part,
The male screw is screwed into the female screw to connect one and the other outer tube members, and the valve member is sandwiched between the ends of the one and the other outer tube members. The chemical | medical solution injection tube for ground improvement of Claim 1 to do. The inner tube has an inner / outer double tube structure in which a second inner tube is provided outside the first inner tube, and a space in the first inner tube is used as a first passage. The space between the outer peripheral surface of the inner tube body and the second inner tube body peripheral surface is used as a second passage, and liquid can be fed to each of the first passage and the second passage,
The tip of the inner tube is provided with a monitor for mixing and mixing the liquid sent through the first passage and the second passage in the internal space, and this monitor is spaced apart from the previous one. 3. The ground improvement material according to claim 1, wherein a side discharge hole in a lateral direction communicating from the inside of the monitor to the outer surface is provided at a position within the interval between the plurality of seal members provided. Chemical injection tube. The main agent is sent to one of the first passage and the second passage, and the curing agent is sent to the other,
In the monitor of the front end portion of the inner tube, the chemical solution composed of the main agent and the curing agent fed through the first passage and the second passage is mixed and mixed in the internal space, and a plurality of portions provided on the side of the monitor 4. The chemical solution injection for ground improvement according to claim 3 , wherein the mixed chemical solution is discharged toward the strainer hole of the outer tubular body from the lateral side discharge hole at a position within the interval of the seal member. tube. The structure capable of closing the second discharge hole is larger in diameter than the inner diameter of the second discharge hole, and falls into the second discharge hole by falling by its own weight in the inner tube facing downward. It is a valve body to fit , The chemical | medical solution injection tube for ground improvement of any one of Claim 1 to 4 characterized by the above-mentioned. A boring bit is provided at the distal end portion of the outer tube body, a second discharge hole is opened in the forward direction of the monitor distal end portion, and the distal end of the first inner tube body is moved forward and backward in the monitor. A movable valve capable of opening and closing the two discharge holes,
The movable valve is a hollow body whose front and rear surfaces are closed, the front side surface and the rear side surface are formed with communication holes into the hollow, and the peripheral surface is provided with a seal member for the inside of the monitor. The entire valve is spring-backed by an elastic body, and the second discharge hole can be opened and closed at the front end, and the front end opening of the first inner tube body can be opened and closed at the rear end. ,
When drilling with a boring bit by rotating the outer tube body, the drilling water is allowed to flow into the second passage while the movable valve closes the first passage, and the drilling water is passed through the rear portion of the movable valve. From the side communication hole through the hollow and further through the front side communication hole, the drilling water flows and is supplied to the boring bit,
On the other hand, at the time of injecting the chemical solution, the movable valve is driven by opening the first passage and the first passage through the first passage and the second passage by applying the chemical main agent and the curing agent to the first passage and the second passage under pressure. The discharge hole of 2 was closed, the main agent and the curing agent were mixed in the monitor, and the chemical solution mixed from the side discharge hole facing the side was supplied to the ground via the strainer hole of the outer tube. The chemical | medical solution injection tube for ground improvement of Claim 3 characterized by these. A boring bit is provided at the distal end portion of the outer tube body, a valve body that can move forward and backward in the monitor to open and close the second discharge hole, and a spring that biases the valve body forward,
A valve seat is provided at a position ahead of the side discharge hole in the lateral direction on the inner peripheral surface of the monitor, and the valve body is brought into close contact with the valve seat by a biasing force of a spring when the valve body is positioned ahead in the monitor. The second discharge hole is closed, and at the same time, a contact portion is provided on the inner side of the boring bit mounting portion at the distal end portion of the outer tube body, and the valve body comes into contact with the contact portion to bias the spring. When the valve body moves backward in the monitor, the valve body is separated from the valve seat and the close contact is released, whereby the second discharge hole is opened,
When drilling to rotate the boring bit in conjunction with the rotation of the outer tube, the inner tube is moved forward to position the monitor in the outer tube tip, and a plurality of sealing members and the outer Close the side discharge hole of the monitor in close contact with the inner peripheral surface of the distal end portion of the tube body, and bring the valve body in the monitor into contact with the abutting portion so that the valve body is rearward from the valve seat And the second discharge hole is opened to allow the drilling water to flow through the first passage and the second passage of the inner tube, and the drilling water is supplied to the valve body and the seating surface in the monitor. To the second discharge hole and supply to the boring bit,
On the other hand, when injecting a chemical solution, the inner tube body is moved backward in the outer tube body, and a strainer hole is positioned at an interval position between a plurality of seal members provided at intervals before and after the side surface discharge hole of the monitor. In the monitor, the valve body is brought into close contact with the valve seat by the urging force of the spring, and the main solution of the chemical and the curing agent are applied to the first passage and the second passage under pressure to flow. were mixed in monitoring the base and curing agent, claims, characterized in that as a chemical solution mixed from the side discharge hole of the lateral direction via the strainer holes of the outer tube is fed into the ground 3 The chemical solution injection pipe for ground improvement described in 1. A ground improvement chemical solution having an outer tube body provided with a plurality of peripheral surface discharge holes in the periphery, and an inner tube body inserted into the outer tube body and provided with a side discharge hole at least in the lateral direction at the tip. In the injection tube,
The outer tube body is a joined body of outer tube members having a configuration in which an end portion of one outer tube member is inserted and joined into an end portion of the other outer tube member,
A strainer hole communicating from the inside of the outer tube body to the outside is formed at the corresponding portion at the end of one outer tube member and the end of the other outer tube member in the coupled state, and one and the other outer tube members A valve member that normally closes the strainer hole between the ends of the tube and opens the strainer hole when the internal pressure of the outer tube is higher than the external pressure,
Provided on the side surface of the distal end portion of the inner tube body are a plurality of seal members that are slidably in close contact with the inner surface of the outer tube body at a distance from each other. A side-facing side discharge hole that communicates with the side surface is provided,
When a pressurized chemical solution is introduced into the inner tube during the injection of the chemical solution, the drug solution is discharged from the side discharge holes to increase the internal pressure in the outer tube between the seal members, and the valve member of the strainer hole is opened. The chemical solution is injected from the strainer hole into the surrounding ground outside the outer tube body,
At the tip of the outer tube body, a tip discharge hole that opens forward and a boring bit are provided,
The distal end portion of the inner tube body is provided with a second discharge hole that opens forward and a structure capable of closing the second discharge hole,
The outer tube and the inner tube are provided with a locking structure that is fixed in the rotational direction relatively when drilling,
The tip discharge hole at the tip of the outer tube body is provided with a check valve that opens with the pressure of drilling water supplied when drilling with a boring bit and blocks the flow from the outside to the tip discharge hole. Chemical solution injection tube for ground improvement. A ground improvement chemical solution having an outer tube body provided with a plurality of peripheral surface discharge holes in the periphery, and an inner tube body inserted into the outer tube body and provided with a side discharge hole at least in the lateral direction at the tip. In the injection tube,
The outer tube body is a joined body of outer tube members having a configuration in which an end portion of one outer tube member is inserted and joined into an end portion of the other outer tube member,
A strainer hole communicating from the inside of the outer tube body to the outside is formed at the corresponding portion at the end of one outer tube member and the end of the other outer tube member in the coupled state, and one and the other outer tube members A valve member that normally closes the strainer hole between the ends of the tube and opens the strainer hole when the internal pressure of the outer tube is higher than the external pressure,
At the same time, the front end portion of the outer tube body is provided with a front end discharge hole that opens forward, and a boring bit,
Provided on the side surface of the distal end portion of the inner tube body are a plurality of seal members that are slidably in close contact with the inner surface of the outer tube body at a distance from each other, and the inner position of the inner tube body from the inside of the inner tube body A side discharge hole in the lateral direction communicating with the outer side surface is provided, and at the same time, a second discharge hole that opens in the forward direction at the distal end portion of the inner tubular body, and a structure capable of closing the second discharge hole Provided,
The outer tube body and the inner tube body are provided with a locking structure that is relatively fixed in the rotational direction when drilling , and the locking structure that is relatively fixed in the rotational direction when drilling is provided with the outer tube body and the inner tube body. In the position corresponding to the drilling of the tubular body, a rotation stop projection is formed on one side and a rotation stop groove is formed on the other side ,
Drilling the ground with the boring bit by simultaneously rotating the outer tube and the inner tube while pumping drilling water from the second discharge hole to the boring bit through the inner tube;
Adding the outer tube and the inner tube until the ground drilling depth reaches a predetermined depth;
After the drilling depth reaches a predetermined depth, the pressurized chemical solution is introduced into the inner tubular body when the chemical solution is injected while the outer tube body is left in the drilled hole, and the chemical solution is supplied to the side surface discharge hole. A chemical solution step of injecting the chemical solution from the strainer hole into the ground around the outside of the outer tube body by opening the valve member of the strainer hole by increasing the internal pressure in the outer tube body between the seal members A chemical solution injection method for ground improvement characterized by this.

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