JP2003096762A - Ground improvement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ground improvement method capable of uniformly injecting a ground improving liquid even into the ground directly under the existing structure by enlarging construction flexibility of a ground improving liquid injection pipe material, executing work even if there is a small work space around the existing structure and reducing part of useless excavation having possibility to cause the destruction of the ground or the destruction of the environment even if a large number of construction holes of the ground improving liquid injection pipe material. SOLUTION: A direction jetting an excavation liquid W is changed by the rotation of an excavation head 3(1) while monitoring positional information to change its boring direction into a straight line and a curved line to form construction holes Ha to Hh by combining the straight line with the curved line. The ground improving liquid is jetted at an objective ground improving area G1 . When the construction holes Ha to Hh are formed, they are shared until part of the way to form branch holes He to Hf from optional branch junctions D1 to D5. Accordingly, there is no need to start boring from a different spot of the ground, the work can be carried out even in the small work space, and the weakness of the ground as well as the diffusion of the polluted water by a backflow of the ground water can be controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement method, and more particularly, to a method suitable for ground improvement on an existing structure ground floor.

[0002]

2. Description of the Related Art Conventionally, it has been practiced to inject a chemical solution in order to improve underground soil conditions, that is, a stratum structure, artificial modification directly under an existing structure, residual foreign matters, cavities and the like. Further, in recent years, in order to recover soil contamination on the direct ground plate of a factory or the like, for example, a liquid containing a microorganism that uses a contaminant as an assimilation substance is permeated into the ground. In this specification, various liquid agents used for improving the ground are collectively referred to as a ground improving liquid.

As a ground improvement method for spraying such a ground improvement solution onto the ground, for example, as in the case widely used in the chemical injection method, the ground is drilled to form a strainer pipe (strainer method) for injecting the chemical solution, Several construction methods are known, such as laying a rod (rod construction method), and sending a chemical solution to this by pressure to eject it onto the ground.

[0004]

However, in the conventional ground improvement method, as shown in FIG. 11, the strainer pipes P ₁ , P ₂ and P ₃ which are rigid bodies are only laid straight down or obliquely downward. I can't. Therefore, with respect to the circumference of the strainer pipes P ₁ , P ₂ , and P ₃ ,
Improvement that allows the soil improvement liquid F to permeate, but most of it does not allow the soil improvement liquid to permeate immediately below the center of the existing structure B ₁ that is a building in the target soil improvement area G _1. It becomes an impossible area.
Therefore, in this conventional method, the strainer pipe P ₁ ,
Existing structure B due to restrictions on laying P ₂ and P ₃
The ground directly underneath ₁ could not be improved evenly.

The existing structure B which is a building₁Beside
Existing structure B like a fence_TwoIs built and the distance is D₁ But
If it is narrow, strainer pipe P₁ , P_Two, P_ThreeLaying work
It is even impossible to do the work. Therefore, without exhaustion
Existing structure B₁To improve the ground beneath, existing structure
Object B₁Shaft H outside₁After drilling horizontally
Side hole H_TwoA hole, and then the horizontal hole H_TwoGround improvement hydraulic pressure inside
Laying pipe material (not shown) for sending and injecting soil improvement liquid F
It is also possible to do it. However, with this, the horizontal hole H_Two
A work space for installing and working a drilling device
Very large vertical shaft H₁Do not dig
It has to be done, so a large-scale construction is required, which is a labor
Not only that, but the economic burden increases, which is not practical. And
If you could solve the problem of increased labor and financial burden
Even so, such a large shaft H₁ Can be excavated
Large site with existing structure B₁, B_TwoMust be secured around
It is important, but in urban areas where buildings and structures are overcrowded
Can't really secure such a large site
The fact is that the shaft H₁Is difficult to drill
It's difficult.

Further, in the conventional construction method, for example, in FIG.
As shown in the drawing, install water and sewer on the laying route such as strainer pipes.
Buried objects B such as pipes and power transmission pipes_ThreeBuried objects such as foundations of pillars and pillars
B_Four If present, avoid them and strainer
Horizontal holes for laying pipes, etc. cannot be laid. That is,
In the example of FIG. 12, the ground improvement area G_TwoAll over the land
In order to permeate the board improving liquid F, a total of 4 pieces, 2 pieces on the top and 2 pieces on the bottom
It is preferable to form the horizontal holes of the
Figurine B_ThreeCan interfere with the horizontal holes,
About one of the two, buried object B_FourBecomes an obstacle
Therefore, the horizontal hole cannot be drilled, and the horizontal hole H shown_ThreeShaving
Can't pierce. Therefore, in the conventional construction method,
Buried object B_Three, B_FourOn the laying route for strainer pipes, etc.
Ground improvement area G_TwoGround break
The good liquid F could not be sufficiently permeated. That
In this case, for example, the horizontal hole H_ThreeIs it the direction intersecting with
Another lateral hole (not shown), but do so
And ground improvement area G_TwoWider floor in all directions (horizontal direction)
Land is needed and implementation is limited especially in urban areas.
It was

Further, in the conventional method shown in FIGS. 11 and 12 as described above, a large number of lateral holes are formed in the ground for laying a strainer pipe or the like, but the ground is weakened due to the weakening of the ground. And the problem of environmental destruction such as groundwater containing pollutants diffusing due to backflow of groundwater through a large number of horizontal holes. In particular, in the example of FIG. 11, the hole portion of each of the lateral holes H ₂ up to the approach to the ground improvement areas G ₁ and G ₂ is a wasteful digging portion, which causes problems such as ground destruction and environmental destruction. From the viewpoint, it is preferable not to have it.

In the conventional method, when a plurality of horizontal holes are formed as in the example of FIGS. 11 and 12, one hole is formed by continuously performing the drilling step and the ground improvement liquid injection step. For example, the work is performed for each adjacent horizontal hole with a time lag such that the hole forming step and the injection step for the adjacent horizontal hole are performed after completing the operation. Therefore, the soil improvement liquid permeated from a certain lateral hole, for example, the ground that is solidifying due to the action of the ground strengthening chemical solution, may be destroyed during the drilling of the next lateral hole, and a sufficient improvement effect by the chemical solution. Can't expect

The present invention has been made against the background of the above conventional techniques, and the present invention has at least one of the following objects.

That is, the first object of the present invention is to improve the degree of freedom in laying a pipe material for injecting a soil improvement liquid, so that the soil improvement liquid can be evenly injected even in the ground directly under an existing structure. To provide.

A second object is to provide a ground improvement method which can be carried out even if there is a small working space around the existing structure.

A third object is to reduce wasteful dug portions that may cause problems such as ground destruction and environmental destruction even if a laying hole for laying a large number of ground improvement liquid injection pipes is formed. This is to provide a ground improvement method that can be done.

A fourth object of the present invention is to provide a ground improvement method which does not impair the consolidating action of the adjacent ground improvement liquid, especially the chemical liquid which acts to strengthen the ground.

[0014]

SUMMARY OF THE INVENTION Therefore, according to the present invention, a plurality of rods having at least two conduits for transporting a drilling fluid and a ground improvement fluid are connected to a front end of the rods along the longitudinal direction, and the respective conduits of the rods are provided. An excavation head having at least two flow channels communicating with each other, a plurality of ejection holes communicating with each flow channel for ejecting a drilling fluid or a ground improvement fluid, and a transmitting means for transmitting its own position information are connected. A ground improvement method using an excavator, which changes the jet direction of the drilling fluid by rotating the drilling head while monitoring the position information from the transmitting means to change the direction of excavation until the target ground improvement area. The laying hole of the rod is formed by ejecting the drilling fluid from the jetting hole while circulating the drilling fluid in the one channel of the rod and the one channel of the excavating head, and the ground improving solution is provided in the ground improving area. Other conduit of rod Providing ground improvement method is jetted from the jet holes while flowing in the other flow path of the drilling head.

In this ground improvement method, while monitoring the position information from the transmitting means, the jetting direction of the drilling fluid is changed by the rotation of the drilling head to change the excavation direction,
Since the drilling fluid is ejected from the ejection holes to form the laying hole of the rod up to the target ground improvement area, the drilling fluid is ejected from the ejection holes while flowing the drilling fluid to the one channel of the rod and the one channel of the excavation head. It is possible to change the excavation direction according to the direction, and it is possible to form a straight line, a curved line, or an arbitrary laying hole in which these are combined. Therefore, the degree of freedom of the laying route is expanded, and it becomes possible to inject the ground improvement liquid evenly into the ground improvement area. And since the excavation head can be changed in the excavation direction by remote control while monitoring the position information from the transmission means, for example, even if the existing structure is not removed, it is possible to accurately lay it directly on the ground board. Holes can be formed. As a specific method of such remote operation, for example, a sensor for detecting the inclination angle with respect to the horizontal, the digging direction, the digging depth, etc. is built in the excavation head, and the detected position information is wired or wirelessly operated on the ground. Alternatively, the operation device may be operated based on the position information. However, if the number of devices incorporated in the excavation head increases, the diameter of the excavation head and the rod increases, which is disadvantageous in that the radius of curvature of the curved installation hole cannot be reduced. Therefore, in order to reduce the radius of curvature of the curved laying hole and make a small turn, for example, the excavation head is equipped with a small transmitter for enabling operation by electromagnetic induction, and the excavation head is installed from the ground. It is preferable to operate by electromagnetic induction. Further, in the ground improvement method, since the flow path of the drilling fluid and the flow path of the ground improving fluid have different configurations, the ground improving fluid can be jetted at any position while the digging proceeds, and It does not mix with the soil improvement solution.

Further, in the ground improvement method, after the ground improvement liquid is ejected, the excavation head is retracted to a predetermined position in the laying hole, and the direction of the digging liquid is changed by the rotation of the excavation head. To form a branch hole from
It is preferable to eject the ground improvement liquid in the target ground improvement area.

According to this, after the ground improvement liquid is ejected, the excavation head is retracted to a predetermined position of the laying hole and the ejection direction of the drilling liquid is changed by the rotation of the digging head so that the branch hole is formed from the middle of the laying hole. Since branch formation is performed and the ground improvement liquid is ejected in the target ground improvement area, even if it is necessary to form a large number of laying holes, it is possible to share up to the branch points of the branch holes. It is possible to reduce the wasteful dug area that may cause problems such as environmental damage and environmental damage. And
When forming a laying hole as a branch hole, it is not necessary to excavate the laying hole from different places on the ground, so it can be used even when there is little work space on the ground, and it can be implemented even in urban areas where existing structures are dense. .

Further, in the above-mentioned ground improvement method, it is preferable to leave the rod and the excavating head in the plurality of laying holes and simultaneously inject the ground improvement liquid from the ground-side rear end of each rod. .

According to this, since the ground improvement liquid is simultaneously injected into a plurality of laying holes, the predetermined action based on the ground improvement liquid is not destroyed when the other laying holes are drilled, and the ground improvement liquid is sufficient. You can expect a great improvement effect.

Further, in the above-mentioned various ground improvement methods, the excavation head opens one passage through which the drilling fluid flows when the drilling fluid is ejected and closes the other passage through which the ground improvement fluid flows. In addition, when the ground improvement liquid is ejected, it is further provided with an opening / closing means for closing the one flow path and opening the other flow path, and in the target ground improvement area, the other pipeline of the rod and the excavation are provided. By circulating the ground improvement liquid in the other flow path of the head, the opening and closing means closes the one flow path through which the drilling liquid flows and the other flow path is opened, and the ground improvement liquid flows from the ejection hole. Can be configured as an injector.

According to this, since the opening / closing means is opened / closed in accordance with the circulation of the drilling fluid and the ground improvement fluid, it is possible to make the device structure skillfully utilizing the flow forces of the drilling fluid and the ground improvement fluid.

The above-mentioned ground improvement method in the present invention is specifically a chemical solution injection method of injecting a chemical solution into the ground as a ground improvement solution, or a liquid containing microorganisms whose assimilation is a ground pollutant (soil pollution source). It can also be implemented as a ground pollution recovery construction method for infiltrating soil into the ground.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. In the following description, the chemical liquid injection method will be described as an example.

In the chemical injection method of this embodiment, a chemical injection device as shown in FIG. 1 is used. That is, this chemical injection device is provided with a head portion 1 and a rod portion 2, and a ground side terminal of the rod portion 2 is an operation device for controlling the excavation direction and the like of the head portion 1 according to a work process (Fig. (Not shown) and a hydraulic equipment M for excavation for imparting excavation force to the head portion 1 (see FIG. 6)
Is connected to a liquid feed pump (not shown) that feeds the drilling liquid or the chemical liquid under pressure.

Structure of Head Part 1 : The head part 1 as a "drilling head" is made of metal and is fastened to the excavating head 3 and the excavating head 3 in order from the tip of the excavating side, the tip having a pointed shape suitable for excavation. The transmission rod 4 and the ejection rod 5 that is fastened to the transmission rod 4 and ejects the chemical solution.

A drilling liquid W is fed to the drilling head 3 as shown in FIG.
As shown in (2), two nozzle holes 6 are formed which eject upward and obliquely forward (FIG. 2). The drilling liquid W ejected from each nozzle hole 6 is supplied to the rod portion 2 by a liquid feed pump on the ground.
Will be pumped through.

The inside of the transmission rod 4 serves as a flow path for allowing the excavation liquid W to flow through the excavation head 3, and is used for detecting the inclination angle of the excavation head 1 with respect to the horizontal, the excavation depth, the excavation direction, and the like. A transmitter unit 7 which has a sensor and wirelessly sends out the detected position information is also incorporated.

The general structure of the jet rod 5 is as shown in FIG. 3, and includes a connecting portion 8 connected to the rear end of the transmitting rod 4.
The circulating portion 9 for the drilling liquid W and the chemical liquid F (F1, F2) and the ejection portion 10 connected to the rear end of the circulating portion 9 are provided.

The connecting portion 8 has a cylindrical shape, and the partition wall 11 formed in the central portion in the longitudinal direction inside the connecting portion 8 has a through hole 1 formed therein.
2 are formed in plural, through which the drilling fluid W flows into the drilling head 3. A cylindrical protrusion 13 is formed on one side wall surface of the partition wall 11. A base end side of an operating spring 15 having a ball valve 14 made of a rubber-like elastic body fixed to the tip end side is held therein. There is.

Inside the flow section 9, a large diameter front side flow chamber 1 is provided.
6, a small diameter intermediate flow chamber 17 and a large diameter rear flow chamber 18 are formed.

Further, in the jet portion 10, a guide chamber 20 is formed along the axial direction of the jet chamber 10 for holding the movable piston 19 and guiding the advancing / retreating of the movable piston 19, and the rear end side of the guide chamber 20 is formed. A connecting member 21 is attached. Reference numerals 22 and 23 denote ejection holes for injecting the chemical liquid F (F1, F2) into the ground, and two ejection holes are provided in this embodiment. Separate chemical liquids F1 and F2 can be ejected from these ejection holes 22 and 23 as described later. And these ejection holes 22, 2
A plurality of circulation holes 24 for the drilling fluid W, which are arranged in a ring shape, are formed outside the guide chamber 20 except for the formation portion of 3.

The structure of the movable piston 19 will now be described. The movable piston 19 is formed with a central hole 25 extending in the axial direction and two through holes 26 and 27 orthogonal to the central hole 25. I am doing it. At the front end of the central hole 25, a conical valve 28 made of a rubber-like elastic material is attached. The front side of the movable piston 19 is inserted into the operating spring 29, and the elastic force of the operating spring 29 constantly urges the movable piston 19 toward the guide chamber 20.

Structure of Rod Part 2: The rod part 2 is made of metal and is connected to the rear end (spouting part 10) of the head part 1 (spouting rod 5) having the above structure. The rod portion 2 includes a joint 30, a sheath pipe 31, and an inner pipe 32,
The ejection part 10 and the sheath pipe 31 are connected via the joint 30, and the one sheath pipe 31 and the other sheath pipe 31 are also connected via the joint 30. In this way, the sheath tube 31 having a length required to reach the head portion 1 to the chemical liquid injection region is successively added by the joint 30.

The joint 30 has a cylindrical shape, and taper threads 30a are formed as male threads on the outer peripheral surfaces of both ends thereof (see FIG. 5). Further, the sheath pipe 31 is also cylindrical, and the inner peripheral surfaces of both ends thereof are formed with a taper screw 31a which is screwed with the taper screw 30a of the joint 30 as a female screw (see FIG. 5). And joint 3
Since 0 and the sheath pipe 31 are joined by screwing the taper screws 30a and 31a together, watertightness can be maintained. Further, the taper screw 30a of the joint 30 and the sheath tube 3
The horizontal planes 30 are provided on both sides of each taper screw 31a.
b and 31b are formed. That is, as will be described later, when the rod portion 2 is curved in an arc shape, the taper screw 30
The bending moment concentrated on a and 31a is applied to the horizontal planes 30b and 31b, so that the taper screw 3
The shape is such that no bending moment is applied to 0a and 31a. Therefore, the watertightness of the taper screws 30a and 31a can be maintained, and at the same time, the taper screw 30 by bending can be maintained.
It is possible to avoid stress concentration on a and 31a and protect them. Further, since the joint 30 is provided with an O-ring 30c, the O-ring 30c and the taper screw 30
Due to the watertightness of both a and 31a, the joint 30 and the sheath tube 3
High water tightness with 1 is secured.

The inner pipe 32 is inserted into the joint 30 and the sheath pipe 31 which are fastened as described above. The inner pipe 32 is shown in FIG.
A male screw (not shown) is formed on the outer peripheral surface of the small diameter portion 33, and a female screw that is screwed with the male screw is formed on the inner peripheral surface on the opposite side. Therefore, when the inner pipes 32 are connected to each other, a member such as the joint 30 is not required and they can be directly connected. A flange member 34 having an outer shape corresponding to the inner peripheral surface shape of the sheath tube 31 is fixed to the outer peripheral surface of the inner tube 32. The collar member 34 is formed with a plurality of annularly arranged circulation holes 35. Therefore, assuming that the joint 30 and the sheath pipe 31 are “outer pipes”, one flow path To is formed between the “outer pipe” and the inner pipe 32 in the rod portion 2, and the inner pipe 32 is formed. Other channel Ti inside
Are formed, and the inner and outer double channels To and Ti are formed as a whole.

Description of Operation : Next, the operation of the chemical liquid injector having the above configuration will be described. First, the head portion 1 and the rod portion 2 are connected to each other, and the ground-side end of the rod portion 2 is connected to the excavation hydraulic device M and a liquid feed pump (not shown) for the drilling liquid W. At the start of drilling, the drilling fluid W is delivered through the flow path To formed between the inner peripheral surfaces of the joint 30 and the sheath tube 31, which are “outer tubes”, and the outer peripheral surface of the inner tube 32. It Then, when reaching the ejection rod 5 of the head portion 1, the drilling liquid W is fed to the ejection rod 5 as shown in FIG.
As shown in (a), the flow-through hole 24 of the jet portion 10 → the rear flow chamber 18 of the flow-through portion 9 and the through-hole 2 of the movable piston 19
6 and the central hole 25 → the middle flow chamber 17 of the flow section 9 → the front flow chamber 16 of the flow section 9 → flows into the transmission rod 4 through the flow hole 12 of the connection section 8 and through the flow path in the drilling head 3 It is jetted obliquely forward as shown in (a).

At this time, the movable piston 19 is constantly urged toward the guide chamber 20 by the operating spring 29.
Therefore, the conical valve 28 is separated from the boundary portion between the rear flow chamber 18 and the intermediate flow chamber 17, so that the drilling fluid W can flow. Further, the drilling fluid W also enters the central hole 25 of the movable piston 19, but since the two through holes 26 and 27 do not overlap any of the ejection holes 22 and 23, the drilling liquid W passes through the ejection holes 22 and 23. The drilling fluid W does not squirt. Further, the drilling fluid W presses the ball valve 14 which is always biased by the actuating spring 15 toward the intermediate flow chamber 17 by its flow force. Therefore, since the boundary portion between the intermediate flow chamber 17 and the front flow chamber 16 is not closed by the ball valve 14, the drilling fluid W can flow into the drilling head 3. The drilling fluid W
When the supply of the pressure is stopped, the ball valve 14 is urged by the actuating spring 15 and liquid-tightly closes the boundary portion. Therefore, the drilling liquid W remaining in the drilling head 3 does not flow backward after the supply of the drilling liquid W is stopped.

When the excavating liquid W is ejected in this manner, the ground located in the excavating direction is soaked in the excavating liquid W and becomes weak, so that the excavating head 3 receives the propulsive force of the excavating hydraulic equipment M on the ground. You will continue to drill. Then, during this drilling, the excavation head 3 can be propelled in any direction. That is, since the drilling fluid W is jetted obliquely forward from the drilling head 3, as shown in FIG. 2, if the drilling head 3 is rotated in the direction R around its axis, the drilling fluid W is jetted in all directions. It is possible to dig the ground in any direction. For example, when the excavation depth is further increased, the excavation head 3 shown in FIG. 2 is rotated until it is turned upside down. In this case, the drilling liquid W is ejected obliquely downward, so that deeper ground can be softened. Similarly, in order to dig to the right with respect to the digging direction, the digging head 3 is rotated so as to lie sideways to the right, and to dig to the left, the digging head 3 is rotated so as to lie sideways to the left. To In order to rotate the excavation head 3 around the axis in this way, the rod portion 2 may be rotated by the excavation hydraulic equipment M on the ground.
The (drilling head 3) rotates in the axial direction R in conjunction with the rotation of the rod portion 2. Note that, instead of such a method, for example, the excavation head 3 is provided inside the transmission rod 4.
You may make it incorporate the actuator which rotates in the direction R around an axis.

Then, from the transmitting rod 4 of the head portion 1, the transmitter unit 7 sends the positional information about the inclination angle of the head portion 1 with respect to the horizontal, the excavation depth, the excavation direction, etc. in real time. This position information is received by a not-shown operating device on the ground, and based on the received position information, the excavation head 3 is rotated in the axial direction R in the above-described manner to change the direction.

As described above, when the head portion 1 and the rod portion 2 are laid while drilling to a predetermined position in the chemical liquid injection region,
Next, a liquid feed pump for the chemical liquid F (F1, F2) is connected to the ground side terminal of the laid rod portion 2 to perform the chemical liquid injection. When performing this chemical injection, the head portion 1 and the rod portion 2 of the present embodiment can simultaneously inject two different types of chemical fluid. That is, one liquid chemical F1 is supplied to the flow path To between the sheath pipe 31 and the inner pipe 32 and another liquid chemical F2 is supplied to the flow passage Ti in the inner pipe 32 using the liquid feed pump.
Then, as shown in FIG. 3B, the chemical liquid F2 supplied to the inner pipe 32 presses the rear end surface 19a of the movable piston 19 through the connecting member 21, and the conical valve 28 causes the rear flow chamber 18 and the intermediate flow chamber 17 to flow. The movable piston 19 moves forward until the boundary portion between and is closed. If you move to this point, the chemical liquid F2
Is vigorously ejected from the guide chamber 20 through the ejection holes 23. On the other hand, the chemical liquid F1 flows through the flow hole 24 of the ejection portion 10.
Through the through hole 26, then into the central hole 25 of the movable piston 19, and through the other through hole 27.
It is spouted vigorously from.

During this chemical injection, the chemical F2
The movable piston 19 is continuously pressed by the fluid pressure of. Therefore, the conical valve 28 is surely closed, the chemical liquid F1 does not flow into the front flow chamber 16, and the force of the chemical liquid F1 ejected from the ejection holes 22 is maintained to be strong, so that the chemical liquid F1 is widely spread in the ground. can do.

Further, since switching between excavation and injection of the chemical liquid is carried out by the movable piston 19 which uses the flow force of the chemical liquid F2 delivered to the inner pipe 32 as a drive source, no special electric system drive source is required and a failure occurs. It can be performed with a simple and small device configuration. Therefore, it has high durability and reliability.

Description of Construction Method : FIG. 6 shows an example of the chemical liquid injection construction method according to this embodiment. FIG. 6 shows the state after the chemical solution F is injected, and the installation hole Ha (Ha1 to Ha1 to
Ha3) ~Hh is in the remaining state ground improvement region _{G 1.} The working process will be described. The above-described head unit 1
Using the rod part 2 and the hydraulic equipment M for excavation on the ground,
We will continue to excavate the ground improvement area G ₁ . As a result,
The laying hole Ha1 shown in (a) is to be formed, and this time the head portion 1 is retracted to the branch point D1 while performing chemical solution injection. Next, at the branch point D1, the ejection direction of the excavation liquid W is changed by the rotation of the excavation head 3 to change the excavation direction, and the hole is drilled again. As a result, the laying hole Ha2 as a "branch hole" shown in FIG. 7B is formed, and the head portion 1 is retracted to the branch point D2 while similarly injecting the chemical solution. Then, when the excavation direction is changed again at the branch point D2 and the hole is drilled again, a laying hole Ha3 as a "branch hole" as shown in FIG. 6A is formed. Then, the head portion 1 is returned to the ground while injecting the chemical liquid F when retreating. This completes the chemical solution injection along the laying hole Ha.

Next, the chemical solution is injected along the laying holes Hb to Hh, but these operations may be performed in the same manner as the laying hole Ha. Although not shown, the laying holes Hb to H
Similarly to the laying hole Ha, a plurality of laying holes (branch holes) are formed to inject the chemical liquid along the line d. Then, when the injection of the chemical along the laying hole Hd is completed, the head portion 1 is retracted to the branch point D3 shown in FIG. 8B, and then the excavation direction is changed at the branch point D3 to proceed with the excavation again. Then, as shown in FIG. 9A, a laying hole He as a branch hole is formed and a chemical solution is injected. In the same manner as described above, the chemical solution is injected while sequentially forming the laying hole Hf as a branch hole from the branch point D4, the laying hole Hg as a branch hole from the branch point D5, and finally the laying hole Hh (Fig. 9 (b), FIG. 6 (b)).

According to such a chemical injection method, it is not necessary to start excavation from different places on the ground in order to form the laying holes Ha2, Ha3, He, Hf, Hg.
Since the branch points D1 to D5 can be shared from the open end on the ground side, it is possible to significantly reduce the wasteful dug portion that may cause problems such as ground destruction and environmental destruction. Also,
Since it is not necessary to start excavation from different places on the ground, it does not require a large work space on the ground and can be carried out even in an urban area where existing structures are densely packed if there is some space.

FIG. 10 shows an example of another construction method. In the conventional method, as shown in FIG. 12, since existing structures B3 and B4 exist in such a scene, even if a large vertical shaft is excavated, a laying hole is formed so as to cover the entire ground improvement area G _2. Although it could not be formed, according to this construction method, four laying holes Hi, H bypassing the existing structures B3, B4.
Since j and Hk (the remaining one does not appear in the figure) can be formed, the chemical liquid F can be uniformly injected into the ground improvement area G ₂ .

Finally, a modified example of the above embodiment will be described. In the above embodiment, the chemical liquid is injected into each of the laying holes Ha to Hk, but the head portion 1 and the rod portion 2 are left in each of the plurality of laying holes, and each of the rod portions 2 is left. You may make it inject a chemical | medical solution simultaneously from the ground side rear end part of this. According to this, since the chemical solution is simultaneously injected into the plurality of laying holes, the consolidating action of the chemical solution that acts to strengthen the ground is not impaired when the adjacent laying holes are drilled.

In the above embodiment, the chemical solution F is injected when the laying holes Ha to Hk are formed and the head portion 1 is retracted, but the chemical solution F may be injected while drilling holes. Even in this case, since the excavation liquid W and the chemical liquid F can be switched reliably and easily, the workability is not significantly lowered, and the excavation liquid W and the chemical liquid F are not mixed.

Further, in the above embodiment, the rod portion 2
A concentric pipe line is formed in the inner and outer double layers of the sheath pipe 31.
Two pipe lines may be provided in parallel inside the.

[0050]

According to the ground improvement method of the present invention, while monitoring the position information from the transmitting means, the direction of jetting of the drilling fluid is changed by the rotation of the drilling head to change the direction of excavation, thereby improving the target ground. The laying hole for the rod is formed by causing the drilling liquid to be jetted from the jet hole while flowing the drilling liquid through the one pipe path of the rod and the one flow path of the drilling head to the region. Therefore, it is possible to change the excavation direction according to the jet direction of the drilling fluid, and it is possible to form a straight line, a curved line, or an arbitrary laying hole in which these are combined. Therefore, the degree of freedom of the laying route is expanded, and it becomes possible to inject the ground improvement liquid evenly into the ground improvement area.

Further, in the ground improvement method of the present invention, after the ground improvement liquid is jetted, the excavation head is retracted to a predetermined position of the laying hole, and the direction of jetting of the drilling liquid is changed by the rotation of the digging head to change the digging hole. Branch holes are diverged from the middle, and the ground improvement liquid is ejected in the target ground improvement area. Therefore, even when it is necessary to form a large number of laying holes, the branch point of the branch hole can be shared, and the wasteful dug portion that may cause problems such as ground destruction and environmental destruction can be reduced. it can. When the laying hole is formed as a branch hole, it is not necessary to excavate the laying hole from different places on the ground. It can be implemented even in urban areas where it is difficult to secure.

Further, according to the present invention in which the ground improvement liquid is simultaneously injected into a plurality of laying holes in the above-mentioned each ground improvement method, a predetermined action based on the ground improvement liquid is impaired by drilling work of other laying holes. Never.

[Brief description of drawings]

1A and 1B are external views of a chemical liquid injector including a head portion and a rod portion according to an embodiment, where FIG. 1A is a front view and FIG. 1B is a plan view.

FIG. 2 is an enlarged operation explanatory view seen from the direction of the SD line shown in FIG.

3A and 3B are explanatory views showing the internal structure of the ejection rod of the head portion of FIG. 1, where FIG. 3A is an operation explanatory view during excavation, and FIG.

4 is a cross-sectional view showing the internal structure of the rod portion of FIG.

5 is an enlarged sectional view taken along the line SE of FIG.

6A and 6B are explanatory views of a chemical liquid injecting method according to one embodiment, where FIG. 6A is a partial cross-sectional view taken along the line SG-SG shown in FIG. 6B, and FIG. ) Arrow SF-SF sectional view taken on the line.

7 is a process explanatory view of the chemical liquid injection method shown in FIG.

FIG. 8 is a process explanatory diagram of the chemical liquid injection method shown in FIG.

9 is a process explanatory view of the chemical liquid injection method shown in FIG.

10A and 10B are explanatory views of a chemical liquid injecting method according to another embodiment, wherein the sectional view (a) is a sectional view taken along the line SI-SI of the sectional view (b) and the sectional view (b) is the sectional view (a). SH-SH sectional view taken on the line of an arrow.

11A and 11B are schematic views for explaining the implementation of a ground improvement method according to a conventional example, in which a sectional view (a) is an explanatory view in which the ground portion is cross-sectional, and a sectional view (b) is an arrow SA-SA line in the sectional view (a) FIG.

FIG. 12 is an explanatory view of the outline of the ground improvement method according to another conventional example, in which the partial diagram (a) is a partial sectional view of the ground taken along the line SC-SC of the partial diagram (b). FIG. 2B) is a plan sectional view taken along the line SB-SB indicated by the arrow in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Head part 2 Rod part 3 Excavation head 4 Sending rod 5 Jetting rod 6 Nozzle hole 7 Transmitter unit 8 Connecting part 9 Flowing part 10 Jetting part 11 Partition wall 12 Flowing hole 13 Projecting part 14 Ball valve 15 Actuating spring 16 Front flow chamber 17 Intermediate flow chamber 18 Rear flow chamber 19 Movable piston 20 Guide chamber 21 Connecting members 22, 23 Injection hole 24 Flow hole 25 Central hole 26, 27 Through hole 28 Conical valve 29 Actuating spring 30 Joint 31 Sheath pipe 32 Inner pipe 33 Small diameter part 34 collar 35 flow hole _G 1, _{G 2} ground improvement zone Ha~Hk laying hole

Claims (4)

[Claims] 1. A front end connecting a plurality of rods having at least two ducts for conveying a drilling fluid and a ground improvement fluid along a longitudinal direction, and at least two flow passages communicating with the respective ducts of the rods. A ground improvement method using a drilling device that connects a drilling head having a plurality of ejection holes communicating with each flow path and ejecting a drilling liquid or a ground improving liquid, and a transmitting means for sending out position information of the own. Then, while monitoring the position information from the transmitting means, the direction of the excavation liquid is changed by the rotation of the excavation head to change the direction of excavation, and the one duct of the rod and the excavation to the target ground improvement area. The digging fluid is circulated through one flow path of the head to be ejected from the ejection hole to form the laying hole of the rod, and the ground improvement fluid is provided in the ground improvement area with the other pipeline of the rod and the digging head. Flow to other channels Ground improvement method is jetted from the jet holes while. 2. After the ground improvement liquid is ejected, the excavation head is retracted to a predetermined position in the laying hole, and the direction of blast of the drilling liquid is changed by the rotation of the excavation head to change from the middle of the laying hole to another ground improvement area. 2. The ground improvement method according to claim 1, wherein the branch holes extending therethrough are formed in a branched manner, and the ground improvement liquid is ejected in the ground region. 3. The ground according to claim 1 or 2, wherein the rod and the excavation head are respectively left in the plurality of laid holes, and the ground improvement liquid is simultaneously injected from the ground-side rear end of each rod. Improved construction method. 4. The excavation head opens one passage through which the drilling fluid flows when the drilling fluid is ejected and closes another passage through which the ground improvement fluid flows, while the one when the ground improvement fluid is ejected. In addition to the opening and closing means for closing the flow path of and opening the other flow path, in the target ground improvement area,
By circulating the ground improvement liquid through the other pipeline of the rod and the other flow passage of the excavation head, the opening and closing means closes the one flow passage through which the drilling fluid flows and the other flow passage is closed. The ground improvement method according to any one of claims 1 to 3, wherein the ground improvement solution is opened and the ground improvement liquid is injected from the ejection holes.