Injection device, soil improvement method, and excavation method

Abstract

To provide a jet device for improving construction efficiency in the ground, and a ground improvement method and an excavation method using the same.SOLUTION: The jet device 1 is used for soil improvement and ground excavation. The injection device 1 includes a rod 2 inserted into the ground, an arm 3 rotatably attached to the rod 2 in a vertical plane and turning in a horizontal plane, and an inward injection nozzle 4 and an outward injection nozzle 4 provided on the arm 3 and injecting the fluid. The inward injection nozzle 4 is provided at an intermediate portion of the arm 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an injection device and a ground improvement method and an excavation method using the same. [Background technology]

[0002] When improving ground that lacks bearing capacity, etc., to make it stronger, a method of mixing the original ground with cement milk in situ is often used. One such method is the jet mixing method. In the jet mixing method, cement milk is sprayed horizontally from the tip of a rotating rod together with compressed air, and the original ground soil and cement milk are mixed while being excavated, thereby creating a ground improvement body.

[0003] Patent Document 1 describes that by providing horizontal stirring blades on a rotating rod, placing inward-facing injection nozzles at the tips of the stirring blades, and placing outward-facing injection nozzles on the rod, the high-pressure jets from these injection nozzles collide with each other and disperse, thereby strongly stirring the ground. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-55955 Summary of the Invention [Problem to be solved by the invention]

[0005] When fluids such as cement milk are injected underground, the momentum of the jet is lost to the surrounding fluids (groundwater and fluids that remain after injection), and after a certain distance, the momentum rapidly decreases, resulting in a decrease in construction efficiency.

[0006] In response to this, by injecting a circular air jet of compressed air so as to cover the outside of the jet of cement milk, etc., it is possible to block contact between the cement milk and the surrounding fluid, placing the jet of cement milk, etc. in a state close to being in the air, and suppressing the attenuation of momentum. However, because the air jet suppresses the agitation and circulation of the surrounding fluid, there are cases in which sufficient agitation cannot be achieved depending on the ground conditions, and it is often necessary to carry out the method multiple times or set an excessive amount of injection.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an injection device that improves underground construction efficiency, and a ground improvement method, excavation method, etc. that use the same. [Means for solving the problem]

[0008] The first invention for solving the above problems is a fluid injection device for use underground, comprising: a rod to be inserted into the ground; an arm rotatably attached to the rod in a vertical plane and pivoting in a horizontal plane; and an inward-facing injection nozzle and an outward-facing injection nozzle provided on the arm for injecting the fluid, wherein the inward-facing injection nozzle is provided in the middle of the arm.

[0009] The injection device of the present invention provides an injection nozzle on an arm rotatably attached to a rod. The arm is positioned vertically to drill a hole in the ground vertically, and then the arm is rotated horizontally to inject a fluid, enabling underground construction work such as ground improvement and excavation. Furthermore, since multiple injection nozzles are provided, these nozzles compensate for the attenuation of the jet's momentum, thereby improving construction efficiency by limiting the construction area to a range where the jet's momentum does not decrease or decreases only slightly. As a result, it is possible to reduce the amount of sludge discharged by reducing the number of construction operations and the injection volume, lower the injection pressure, and shorten the construction period. In particular, the inward-facing injection nozzle is provided at the middle of the arm's extension direction rather than at the tip to ensure construction within the radially inner portion of the construction area. Furthermore, by arranging multiple injection nozzles facing inward and outward, the injection reaction force of one injection nozzle can be offset by the injection reaction force of the other injection nozzle, thereby reducing stress acting on the rod.

[0010] The jetting device may be used, for example, for ground improvement, the fluid may include cement, or the jetting device may be used for excavating ground. The injection device can be used for ground improvement by injecting a fluid containing cement, such as cement milk, or for excavating the ground by injecting a fluid such as water.

[0011] In a cross section perpendicular to the extension direction of the arm, it is desirable that the positions of the inward-facing jet nozzle and the outward-facing jet nozzle be different. This makes it possible to prevent interference between jets from opposing jet nozzles, and also to prevent one jet nozzle from being damaged by the jet from the other jet nozzle.

[0012] It is desirable to further include a lifting jig for lifting the arm and rotating it upward. The lifting jig is, for example, a hook provided on the arm, and the wire rod lowered from the ground is attached to the hook. In the present invention, the arm can be pulled up and rotated reliably by using a lifting jig. By using the hook as the lifting jig, the structure of the jig can be simplified.

[0013] It is also desirable that the inward-facing jet nozzles and the outward-facing jet nozzles are arranged at the same position in the extension direction of the arms and spaced apart in the circumferential direction of a cross section perpendicular to the extension direction of the arms. This allows the jet to cover most of the area around the arm axis, ensuring reliable construction.

[0014] The second invention is a ground improvement method using the injection device of the first invention, characterized by comprising the steps of: inserting the rod into the ground while the arm is oriented vertically downward and injecting fluid downward from the outward-facing injection nozzle to drill a hole in the ground; rotating the arm upward to a horizontal position while injecting fluid from at least one of the inward-facing injection nozzle and the outward-facing injection nozzle; and rotating the arm in a horizontal plane while injecting fluid from both the inward-facing injection nozzle and the outward-facing injection nozzle, thereby stirring the ground and the fluid and improving the ground. The third invention is an excavation method using the injection device of the first invention, comprising the steps of inserting the rod into the ground while orienting the arm vertically downward and injecting fluid downward from the outward-facing injection nozzle to bore a hole in the ground, rotating the arm upward to a horizontal position while injecting fluid from at least one of the inward-facing injection nozzle and the outward-facing injection nozzle, and excavating the ground in a cylindrical shape by rotating the arm in a horizontal plane and raising and lowering the rod while injecting fluid from both the inward-facing injection nozzle and the outward-facing injection nozzle. The second and third inventions are a ground improvement method and an excavation method, respectively, that use the injection device of the first invention. [Effects of the Invention]

[0015] The present invention can provide an injection device that improves the efficiency of underground construction, and a ground improvement method, excavation method, etc. that use the same. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing an injection device 1. FIG. [Figure 2] 3 is a diagram for explaining the momentum of the jet from the injection nozzle 4. FIG. [Figure 3] FIG. 3 is a diagram showing the working range of the injection nozzle 4. [Figure 4] FIG. 3 is a diagram showing the position of the injection nozzle 4. [Figure 5] FIG. 1 is a diagram explaining a ground improvement method. [Figure 6] FIG. 2 is a diagram showing an injection device 1a. [Figure 7] FIG. 3 is a diagram showing the position of the injection nozzle 4. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0018] (1. Injection device 1) Figure 1 is a diagram showing the main parts of an injection device 1 according to an embodiment of the present invention. The injection device 1 performs ground improvement by injecting cement milk into the ground, and by stirring and mixing the soil and sand of the original ground with the cement milk while cutting the original ground, thereby constructing a cylindrical ground improvement body. Cement milk is a cement-based solidification material in the form of a slurry (fluid) containing cement.

[0019] The injection device 1 includes a rod 2, an arm 3, an injection nozzle 4, a hook 5, a wire 6, and the like.

[0020] The rod 2 is a cylindrical metal member that hangs down from a construction machine on the ground and is inserted into the ground. A flow path (not shown) for cement milk or the like is provided inside the rod 2. The rod 2 can be the same as that used in conventional jet mixing methods, but it is also possible to use a rod specifically designed for this device.

[0021] Arm 3 is an opening / closing / mixing blade that is connected to the lower end of rod 2 so as to be rotatable in a vertical plane around a rotation axis 31. A swivel, for example, is used for rotation axis 31, and the angle of arm 3 can be changed between the vertical position and horizontal position shown in Figure 1. The length of arm 3 is set to approximately the radius of the construction area of ​​the ground improvement body, so that when arm 3 is in a horizontal position, the tip of arm 3 can reach the outer edge of the construction area (see Figure 3 below). Arm 3 is a cylindrical metal member, and like rod 2, a flow path for cement milk or the like is provided inside it.

[0022] An attachment portion 32 for the jet nozzle 4 is provided at a base side (corresponding to the rod 2 side) in the extension direction of the arm 3. In this embodiment, an attachment portion 32 for the jet nozzle 4 is also provided at an intermediate portion between both end portions of the arm 3 in the extension direction.

[0023] The jet nozzle 4 is a nozzle that jets cement milk or the like along the extension direction of the arm 3. The jet nozzle 4 of this embodiment is configured to jet only the construction fluid such as cement milk or the like (single jet) without jetting compressed air. In this embodiment, by jetting only cement milk or the like, intense agitation occurs around the jet, achieving excellent construction efficiency.

[0024] In the case of a single jet, as mentioned above, a sudden drop in momentum of the jet occurs, but in this embodiment, the drop in momentum is compensated for by attaching the jet nozzles 4 to the above-mentioned multiple mounting portions 32 and arranging them in multiple stages in the extension direction of the arm 3.

[0025] Figure 2 shows an outline of the momentum of a jet of cement milk or the like sprayed from the spray nozzle 4. The momentum of the jet remains the same until it is a certain distance D away from the spray nozzle 4, but once it exceeds this distance D, it begins to decay and eventually becomes zero.

[0026] In this embodiment, taking into consideration this decrease in momentum, as shown in Figure 1, the jet nozzles 4 are attached to each of the above-mentioned attachment parts 32 so that their jet directions face each other. That is, the attachment part 32 at the base of the arm 3 has a jet nozzle 4 (4-1) attached to it facing outward toward the tip side in the extension direction of the arm 3 (corresponding to the opposite side of the rod 2), and the attachment part 32 at the middle part of the arm 3 has a jet nozzle 4 (4-2) attached to it facing inward toward the base side in the extension direction of the arm 3. The tips of these jet nozzles 4 are located at approximately the same position in the center of the extension direction of the arm 3.

[0027] As a result, as shown in FIG. 3, the arm 3 is placed in a horizontal position, and cement milk is sprayed from the outward spray nozzle 4 (4-1) in the range R corresponding to the section of the distance D in the outer radius part of the construction range R. 外 The ground is improved by injecting cement milk from the inward injection nozzle 4 (4-2) to the area R corresponding to the distance D in the radially inner part of the construction area R. 内 This allows the construction range R to be set within a range in which the momentum of the cement milk jet does not decrease.

[0028] FIG. 4 is a view of the arm 3 as seen from the tip end in the extension direction. As shown in FIG. 4, the above-mentioned jet nozzles 4 (4-1, 4-2) are provided at different positions in the circumferential direction of the arm 3 in a cross section perpendicular to the extension direction of the arm 3. This makes it possible to prevent interference between jets from opposing jet nozzles 4. It also makes it possible to prevent one jet nozzle 4 from being damaged by the jet from the other jet nozzle 4. There are no particular restrictions on the separation angle θ between the jet nozzles 4, but if the jet nozzles 4 are placed too far apart, there is a concern that the ground may not be stirred sufficiently, so the separation angle θ is preferably about 5° to 30°.

[0029] Returning to the explanation of Figure 1, hook 5 is a lifting jig attached to the base end of arm 3. The lower end of wire 6 hanging down from the ground is attached to hook 5. By pulling wire 6 upward from the ground, arm 3 can be rotated in a vertical plane and changed from the vertical position shown in Figure 1 to a horizontal position. When wire 6 is loosened, arm 3 returns from the horizontal position to the vertical position due to its own weight.

[0030] (2. Ground improvement method) Figure 5 is a diagram illustrating a ground improvement method using an injection device 1. In this embodiment, as shown in Figure 5(a), the injection device 1 is attached to a construction machine 8 placed on the ground, and a drilling fluid (water or cement milk) is pumped from an external pump (not shown) and supplied to the injection device 1. The construction machine 8 can be a construction machine used in conventional jet mixing methods, but it can also be a construction machine 8 dedicated to this device.

[0031] The arm 3 is in a vertical position and faces vertically downward. The fluid passes through the rod 2 and arm 3 and is sprayed downward from the outward-facing spray nozzle 4 (4-1). This fluid is used to drill a hole in the ground, and the rod 2 is inserted into the ground as shown in Figure 5(b). Multiple rods 2 are used, one after the other, depending on the drilling depth. The fluid is also sprayed upward from the inward-facing spray nozzle 4 (4-2). This also stirs the ground around the hook 5 and wire 6, making it easier to perform the arm 3 lifting process described below.

[0032] Then, the fluid is sprayed from both the outward-facing spray nozzle 4 (4-1) and the inward-facing spray nozzle 4 (4-2) to agitate the ground around the arm 3, while pulling the wire 6 upward, thereby pulling the arm 3 as shown by arrow a in Figure 5 (c), and rotating the arm 3 upward in the vertical plane until it assumes a horizontal position.

[0033] After the arm 3 is thus placed in a horizontal position, cement milk is supplied to the sprayer 1, and while the cement milk is sprayed from both the outward-facing spray nozzle 4 (4-1) and the inward-facing spray nozzle 4 (4-2), the construction machine 8 on the ground rotates the rod 2 around its axis, and the arm 3 is rotated in a horizontal plane around the rod 2. This cuts the ground, stirring and mixing the soil and cement milk. By raising and lowering the rod 2 while spraying the cement milk and rotating the arm 3, a cylindrical ground improvement body is created as shown in Figure 5(d).

[0034] Here, if there is an area where the ground is not sufficiently mixed when the arm 3 rotates, the arm 3 will get caught on the ground and will not be able to rotate in a horizontal plane. In other words, if the arm 3 can rotate, it can be determined that the ground has been mixed in that area. As mentioned above, the length of the arm 3 corresponds to the radius of the construction area, so if the arm 3 can rotate 360°, it means that the ground improvement diameter can be guaranteed.

[0035] Furthermore, in the injection device 1, an injection nozzle 4 is attached to an arm 3 rotatably attached to a rod 2, and by positioning the arm 3 vertically to drill holes in the ground vertically, and then rotating the arm 3 horizontally to inject cement milk, it is possible to create a cylindrical ground improvement body. This eliminates the need to change jigs and equipment when drilling and improving the ground, simplifying the construction procedure and shortening the construction period.

[0036] As described above, in this embodiment, multiple jet nozzles 4 are provided on the arm 3. These jet nozzles 4 compensate for the attenuation of the jet momentum, and the construction area is defined as an area where the momentum of the jet does not decrease or decreases only slightly, thereby improving construction efficiency. As a result, it is possible to reduce the amount of sludge discharged by reducing the number of constructions and the amount of injection, lower the injection pressure, shorten the construction period, and reduce the variation in the strength of the improved structure. In particular, the inward-facing jet nozzle 4 is provided not at the tip of the arm 3 but at the middle of the extension direction of the arm 3 to ensure construction within the radially inner portion of the construction area. Furthermore, by arranging multiple jet nozzles 4 facing inward and outward, the jet reaction force of one jet nozzle 4 can be offset by the jet reaction force of the other jet nozzle 4, thereby reducing the stress acting on the rod 2.

[0037] In this embodiment, the outward jet nozzle 4 (4-1) and the inward jet nozzle 4 (4-2) are positioned differently in a cross section perpendicular to the extension direction of the arm 3, which prevents interference between jets from opposing jet nozzles 4. It also prevents one jet nozzle 4 from being damaged by the jet from the other jet nozzle 4.

[0038] Furthermore, conventional jet mixing methods have the problem that no quality control method has been established to ensure the shape of the ground improvement body, and it is necessary to confirm after construction that the required quality is met. Currently, sensors such as thermocouples are installed in advance at positions corresponding to the outer edges of the construction area, and the improved diameter is confirmed by measuring the temperature change after cement milk is injected, but in this embodiment, by using an arm 3 with the same length as the radius of the construction area, the improved diameter can be guaranteed as described above, and confirmation of the improved diameter using a thermocouple or the like is no longer necessary. However, to be sure, it is possible to confirm the improved diameter by conducting a separate inspection using a thermocouple or the like.

[0039] In addition, in this embodiment, when the arm 3 is pulled up and rotated, a fluid is sprayed from the spray nozzle 4 to agitate the ground around the arm 3, thereby reducing friction between the arm 3 and the ground and allowing the arm 3 to be pulled up easily.

[0040] In this embodiment, the arm 3 can be pulled up and rotated reliably by using a pulling-up jig. The pulling-up jig is the hook 5, and the arm 3 is pulled up using the wire 6, which simplifies the jig configuration and does not require major modifications to the conventional rod 2.

[0041] However, the present invention is not limited to the above embodiment. For example, in this embodiment, the hook 5 and the wire 6 are used as a lifting jig for lifting and rotating the arm 3, but the lifting jig is not limited to this. For example, a hydraulic or pneumatic actuator may be used.

[0042] The nozzle diameter of the jet nozzle 4 at each position in the extension direction of the arm 3 is determined based on the area covered by each jet nozzle 4 (for example, the area R 内 , R 外 The nozzle diameter of the jet nozzle 4 can be adjusted according to differences in the area of ​​the arm 3, thereby preventing excessive spray flow. For example, if the treatment area is small, the nozzle diameter of the jet nozzle 4 can be made smaller. Alternatively, the position of the jet nozzle 4 in the extension direction of the arm 3 can be adjusted to make the treatment area covered by the jet nozzle 4 at each point in the extension direction of the arm 3 equal. In this case, the nozzle diameter of the jet nozzle 4 can be made the same at each point in the extension direction of the arm 3. Therefore, there is no need to prepare parts with different nozzle diameters, and there is no risk of incorrectly attaching the nozzle.

[0043] Furthermore, in this embodiment, the jet nozzles 4 are provided at two locations in the extension direction of the arm 3, and there is one jet nozzle 4 per location in the extension direction, but the arrangement of the jet nozzles 4 is not limited to this. The jet device 1a in FIG. 6 is an example, and by providing jet nozzles 4 at four locations in the extension direction of the arm 3, it is possible to accommodate larger areas of construction. Furthermore, the jet nozzles 4 (4-1 to 4-4) provided at each location in the extension direction of the arm 3 are oriented outward, inward, outward, and inward, in that order, from the base side to the tip side of the arm 3. This allows the jet reaction force of the inward-facing jet nozzle 4 to be offset by the jet reaction force of the outward-facing jet nozzle 4, and also reduces the stress acting on the rod 2.

[0044] Figure 7 is a view of the arm 3 in Figure 6 as seen from the tip end in its extension direction. As shown in Figure 7, of the above-mentioned jet nozzles 4, two jet nozzles 4 (4-3, 4-4) at the tip end of the arm 3 are arranged at intervals around the arm 3 in a cross section perpendicular to the extension direction of the arm 3 (three in the example of Figure 7). This allows a structure in which the jet flow covers most of the area around the axis of the arm 3, ensuring reliable ground improvement. Furthermore, in a cross section perpendicular to the extension direction of the arm 3, the outward-facing jet nozzle 4 (4-3) and the inward-facing jet nozzle 4 (4-4) are positioned at different circumferential positions around the arm 3. Therefore, the jet nozzles 4-3 and 4-4 do not face each other, reducing interference between the jets.

[0045] The above configuration also applies to the two jet nozzles 4 (4-1, 4-2) at the base side of the arm 3. The angle θ between the jet nozzles 4 is not particularly limited, but it is preferable that the angle θ is about 45°.

[0046] In this embodiment, the arm 3 is rotated upward in a vertical plane to a horizontal position while fluid is sprayed from both the outward-facing spray nozzle 4 and the inward-facing spray nozzle 4, but depending on the configuration of the spray device, the arm 3 may be rotated while fluid is sprayed from either the outward-facing spray nozzle 4 or the inward-facing spray nozzle 4.

[0047] The injection device 1 can also be used to excavate the ground in a cylindrical shape. In this case, the fluid injected from the injection nozzle 4 is water or the like, and the process described in Fig. 5 is carried out, and the fluid mixed with soil and sand is discharged from the excavation hole.

[0048] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications or alterations within the scope of the technical ideas disclosed herein, and it is understood that these modifications also fall within the technical scope of the present invention.

[0049] For example, in the present embodiment, examples have been shown in which water or cement milk is used as the fluid, but this is not limitative. Cement-free ground improvement materials, concrete, or viscous fluids containing thickeners may also be used as the fluid. [Explanation of symbols]

[0050] 1, 1a; Injection device 2: Rod 3: Arm 4, 4-1, 4-2, 4-3, 4-4: Injection nozzle 5: Hook 6: Wire rod

Claims

1. 1. A fluid injection device for use underground, comprising: a rod inserted into the ground; an arm rotatably attached to the rod in a vertical plane and pivoting in a horizontal plane; an inward-facing injection nozzle and an outward-facing injection nozzle provided on the arm for injecting the fluid; Equipped with An injection device characterized in that the inward-facing injection nozzle is provided at an intermediate portion of the arm.

2. 2. The injection device according to claim 1, wherein the injection device is used for ground improvement.

3. The injection device is used for ground improvement, 3. The injector of claim 2, wherein the fluid comprises cement.

4. 2. The injection device according to claim 1, wherein the injection device is used for excavating the ground.

5. 2. The injection device according to claim 1, wherein the positions of the inward-facing injection nozzle and the outward-facing injection nozzle are different in a cross section perpendicular to the extension direction of the arm.

6. 2. The injection device according to claim 1, further comprising a lifting tool for lifting and rotating the arm upward.

7. the lifting jig is a hook provided on the arm, 7. The injection device according to claim 6, wherein a wire rod lowered from the ground is attached to said hook.

8. 2. The injection device according to claim 1, wherein a plurality of the inward-facing injection nozzles and a plurality of the outward-facing injection nozzles are arranged at the same position in the extension direction of the arms and spaced apart in the circumferential direction of a cross section perpendicular to the extension direction of the arms.

9. A ground improvement method using the injection device according to claim 1, a step of inserting the rod into the ground while boring a hole in the ground by jetting fluid downward from the jet nozzle facing outward with the arm oriented vertically downward; a step of rotating the arm upward to a horizontal position while jetting fluid from at least one of the inward jet nozzle and the outward jet nozzle; a step of stirring the ground and the fluid to improve the ground by rotating the arm in a horizontal plane and raising and lowering the rod while injecting fluid from both the inward-facing injection nozzle and the outward-facing injection nozzle; A ground improvement method comprising the steps of:

10. 2. A drilling method using the injection device according to claim 1, a step of inserting the rod into the ground while boring a hole in the ground by jetting fluid downward from the jet nozzle facing outward with the arm oriented vertically downward; a step of rotating the arm upward to a horizontal position while jetting fluid from at least one of the inward jet nozzle and the outward jet nozzle; a step of excavating the ground in a cylindrical shape by rotating the arm in a horizontal plane and raising and lowering the rod while spraying fluid from both the inward-facing spray nozzle and the outward-facing spray nozzle; A drilling method comprising:

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