JP5573235B2 - Jet agitator and ground improvement method - Google Patents

Description

  The present invention relates to a jet stirring device and a ground improvement method, and more particularly to a jet stirring device and a ground improvement method effective for improving the ground directly under a structure.

  In recent years, in order to improve the ground directly under existing structures such as LNG tanks built under the old earthquake resistance standard, to prevent liquefaction of the ground due to earthquakes and to prevent collapse of existing structures due to liquefaction, etc. A chemical solution is injected into the ground directly under the object to strengthen the ground directly below.

  For example, as shown in FIG. 24, a hole 43 penetrating the existing structure 40 is drilled from directly above the existing structure 40, and the ground 41 directly below the existing structure 40 using the drilled borehole 43. 25. A method for improving the ground by injecting a solidified material into the ground or agitating with high-pressure jet, etc., and as shown in FIG. 25, the ground 41 is drilled obliquely downward from the side of the existing structure 40, and the drilled borehole 43, a method for improving the ground by injecting solidified material into the ground directly under the existing structure 40 or by high-pressure jet stirring, as shown in FIG. 26, on the ground 41 on the side of the existing structure 40 A vertical shaft 44 is provided, the ground 41 is drilled horizontally from the vertical shaft 44, and solidified material is injected into the ground 41 directly below the existing structure 40 using the drilled bore hole 43 or high-pressure jet stirring is performed. The method of improving the ground by doing etc. is adopted .

  By the way, among the ground improvement methods as described above, the ground improvement method of FIG. 24 cuts roads and railways so as to avoid the holes 43 when the existing structure 40 is a road or railway. Later, it is necessary to improve the ground 41 directly under the existing structure 40. Further, when the existing structure 40 cannot be cut like an LNG tank or the like, the existing structure 30 is extracted after the contents of the LNG tank or the like are removed and the floor board is partially broken in order to cut the hole 43. It is necessary to improve the ground 41 immediately below.

  In the ground improvement method of FIG. 25, when the area of the existing structure 40 is large, the hole 43 cannot be drilled to the vicinity of the center immediately below the existing structure 40. Can not.

  Furthermore, the ground improvement method of FIG. 26 excavates the vertical shaft 44 along the existing structure 40 in the ground around the existing structure 40, and the ground improvement is performed from this vertical resistance 44. Is located at a deep position, the excavation work of the vertical shaft 44 becomes large-scale. In addition, it is difficult to improve the ground below the groundwater level.

In order to cope with the above problems, it is conceivable to employ the ground improvement method described in Patent Document 1.
The ground improvement method described in Patent Document 1 uses a flexible excavating rod, and by excavating the excavating rod from an excavator installed on the ground, the ground is drilled obliquely downward to a predetermined depth and excavated. Further drilling is performed while changing the direction of the rod toward the construction target region, and the tip of the excavation rod is made to reach a predetermined position.

  Then, a tubular casing is inserted into the drilled boring hole so as to surround the excavating rod, the tip of the casing reaches the face of the tip of the boring hole, the excavating rod is pulled out from the casing to the ground, Insert a monitor (solidifying material filling means) from the ground to make the tip reach the face.

  And while pulling out the casing to the ground side, the monitor is rotated (180 ° or 360 ° alternately rotated in the clockwise and counterclockwise directions and rotated in the reverse direction), and the cutting fluid is ejected from the tip of the monitor, and the solidified material By repeatedly injecting the solid material, high-pressure injection of the solidified material into the drilled borehole, creating a ground solid body having a horizontal part in the ground construction target area, and improving the ground in the construction target area It is to do.

  By using the ground improvement method described in Patent Document 1, the above-described problems in the ground improvement method described with reference to FIGS. 24 to 26 can be solved, and the ground directly under an existing structure can be improved. it can.

However, in the ground improvement method described in Patent Document 1, when the monitor 46 is inserted into the casing 45 from the ground as shown in FIG. 27, the monitor 46 first hits A ′ in FIG. 28, and then, along the shape of the casing 45 as shown in FIG. 28, finally hits the bent portions A and B in FIG. For this reason, it is difficult to make the center line of the casing 45 coincide with the center line of the monitor 46, and when the monitor 46 is rotated, the resistance of the contact portions A and B with the casing 45 of the monitor 46 increases. 46 cannot be smoothly rotated, and the solidified material cannot be uniformly injected onto the surrounding ground. Furthermore, since the contact portions A and B of the monitor 46 with the casing 45 are easily worn, the durability of the monitor 46 is lowered.
Furthermore, since many processes as described above are performed, it takes time, labor and cost to improve the ground directly under the existing structure.

Japanese Patent Laid-Open No. 2006-45847

  An object of the present invention is to provide a jet agitating apparatus and a ground improvement method capable of easily performing ground improvement directly under an existing structure in a short time without much expense.

In order to solve the above problems, the present invention employs the following means.
That is, the present invention includes an outer tube formed of a material having a flexible material, is rotatably supported about the axis of the outer tube to the outer tube is formed from a material having a flexible material A drilling rod comprising an inner tube, a drilling head provided at the tip of the inner tube and rotatable integrally with the inner tube, and a drilling hole provided at the tip of the drilling head of the drilling rod A discharge hole for discharging the liquid; an injection hole for injecting a solidified material provided behind the discharge hole of the drilling head; a first supply path for supplying a drilling liquid to the discharge hole; and a second supply path for supplying the solidifying material in the hole, the inner tube extends concentrically over the inner side of the outer tube to the entire length, it characterized that you have is rotatably supported at a plurality of positions.

According to the jet stirring device of the present invention, drilling is performed while discharging the drilling liquid from the discharge hole, and at this time, the solidified material is jetted from the spray hole to stir and mix the surrounding ground and the solidified material. The solidification material can be injected into the ground of the area to be improved and strengthened.
Further, since the inner tube is supported inside the outer tube so as to be rotatable around the axis of the outer tube, the outer tube and the inner tube may interfere locally even when the drilling rod is curved. There is nothing, and it is possible to smoothly rotate the inner tube and the drilling head and to prevent the inner tube from being worn.

Further, in the present invention, the tip of the front Symbol drilling head tip bits inclined at a predetermined angle may be provided integrally to the axis of the inner tube.

According to the jet agitating device of the present invention, when the drilling rod is pushed into the ground with the rotation of the drilling head stopped, the tip bit receives resistance from the ground, and the drilling rod becomes the tip bit of the tip bit. By bending and deforming according to the inclination angle, the traveling direction of the drilling rod is changed, and by restarting the rotation of the drilling head, the drilling rod can be advanced in that direction.
Therefore, even if there are obstacles in the ground directly under the existing structure or when the area of the existing structure is large, the tip of the drilling rod reaches the area to be improved in the ground directly under the existing structure. It is possible to stir and mix the ground in the area to be improved and the solidified material, and inject the solidified material into the ground in the area to be improved to strengthen the area.

  Furthermore, in the present invention, the first supply path may be provided between the outer pipe and the inner pipe, and the second supply path may be provided inside the inner pipe.

  According to the jet stirring device of the present invention, the drilling liquid is supplied to the discharge hole via the first supply path between the outer pipe and the inner pipe, and the jet hole is supplied via the second supply path inside the inner pipe. Solidification material will be supplied to the.

  Furthermore, in the present invention, the inner tube is composed of a first inner tube and a second inner tube provided inside the first inner tube, and the first tube is disposed between the first inner tube and the outer tube. 1 supply path is provided, the second supply path for supplying the solidification material to the injection hole is provided inside the second inner pipe, and the first inner pipe and the second inner pipe are disposed between the first inner pipe and the second inner pipe. A third supply path for supplying a fluid to an auxiliary injection hole provided so as to surround the injection hole may be provided around the injection hole.

According to the jet agitating device of the present invention, the drilling liquid is supplied to the discharge hole via the first supply path between the first inner pipe and the outer pipe, and the second supply path inside the second inner pipe is passed through the first supply path. Thus, the solidifying material is supplied to the injection hole, and the fluid is supplied to the auxiliary injection hole via the third supply path between the first inner pipe and the second inner pipe.
Therefore, since the friction between the solidified material injected from the injection holes and the surrounding ground can be reduced, the solidified material is sprayed in a wider range, and the wide area of the ground in the improvement target area is stirred and mixed with the solidified material. Solidification material can be injected and strengthened in the ground in a wide area.

  Further, in the present invention, the drilling rod includes a single outer tube, a single inner tube rotatably supported through a bearing inside the single outer tube, and both ends of the single outer tube and the single inner tube. An extension unit comprising a connecting means provided in the section, a single outer pipe, a single inner pipe rotatably supported via a bearing inside the single outer pipe, the single outer pipe and the single inner pipe The drilling head provided at one end, and a head unit comprising the single outer tube and a connecting means provided at the other end of the single inner tube, the head unit including at least one extension unit. It is good also as connecting in series via the said connection means.

  According to the jet stirring device of the present invention, the drilling rod can be set to a length corresponding to the length of the hole to be drilled by connecting one or more extension units to the head unit. In this case, the extension unit may be connected to the head unit via the connecting means, and the extension units may be connected to each other via the connecting means, so that the length corresponding to the length of the hole for drilling the drilling rod can be easily obtained. Can be set to The single inner pipe of the extension unit is rotatably supported inside the single outer pipe via a bearing, and the single inner pipe of the head unit is rotatably supported inside the single outer pipe via a bearing. Therefore, the single outer pipe and the single inner pipe of the extension unit do not interfere with each other, and the single outer pipe and the single inner pipe of the head unit do not interfere with each other. The inner tube and the drilling head can be smoothly rotated.

  Furthermore, in the present invention, the connecting means may be a combination of a screw portion provided at an end portion of the single outer tube and a fitting portion provided at an end portion of the single inner tube.

  According to the jet agitating apparatus of the present invention, the screw portion provided at the end of the single outer tube of the head unit, the fitting portion provided at the end of the single inner tube, and the end of the single outer tube of the extension unit are provided. The head unit and the extension unit are connected to each other by connecting the threaded portion and the fitting portion provided at the end of the single inner tube to each other. Also, a screw portion provided at the end of the single outer tube of one extension unit, a fitting portion provided at the end of the single inner tube, and a screw provided at the end of the single outer tube of the other extension unit The two extension units are connected to each other by connecting the fitting portion and the fitting portion provided at the end of the single inner tube.

  Furthermore, the present invention is a ground improvement method for improving the ground directly under the existing structure using the jet agitating device according to any one of claims 1 to 6, and from the ground on the side of the existing structure, The ground is drilled obliquely downward with the drilling rod, the tip of the drilling rod is made to reach a depth corresponding to the improvement target area of the ground directly under the existing structure, and the orientation of the drilling rod is While changing toward the improvement target region, a drilling step for reaching the tip of the drilling rod through the improvement target region, and while pulling out the drilling rod, the solidification material is injected from the injection hole, A solidifying material injecting step of injecting a solidifying material into the area to be improved by injecting a fluid from the auxiliary injection holes as necessary is provided.

  Furthermore, the present invention is a ground improvement method for improving the ground directly under the existing structure using the jet agitating device according to any one of claims 1 to 6, and from the ground on the side of the existing structure, The ground is drilled obliquely downward with the drilling rod, the tip of the drilling rod is made to reach a depth corresponding to the improvement target area of the ground directly under the existing structure, and the orientation of the drilling rod is While changing toward the improvement target region, a drilling step for causing the tip of the drilling rod to reach the improvement target region, and discharging the drilling liquid from the discharge hole, and injecting the solidified material from the injection hole, A solidifying material injecting step of injecting a solidifying material into the region to be improved by further advancing the drilling rod while injecting a fluid from the auxiliary injection holes as necessary.

  Furthermore, the present invention is a ground improvement method for improving the ground directly under the existing structure using the jet agitating device according to any one of claims 1 to 6, and from the ground on the side of the existing structure, The ground is drilled obliquely downward with the drilling rod, the tip of the drilling rod is made to reach a depth corresponding to the improvement target area of the ground directly under the existing structure, and the orientation of the drilling rod is While changing toward the improvement target region, the tip of the drilling rod reaches the position penetrating the improvement target region, and while changing the direction of the drilling rod diagonally upward, the tip of the drilling rod is changed. A drilling step for reaching the ground, and solidifying the region to be improved by injecting solidified material from the injection hole while pulling out the drilling rod and, if necessary, injecting fluid from the auxiliary injection hole. Solidification by jetting material Characterized in that it comprises a jetting step.

  As described above, according to the jet agitating apparatus and the ground improvement method of the present invention, the ground directly under the existing structure can be easily improved in a short time without spending a great deal of cost. it can. Moreover, even when an obstacle exists in the ground directly under the existing structure, the ground on the back side of the obstacle can be improved while avoiding the obstacle. Furthermore, even if the drilling rod is bent, the inner tube is supported inside the outer tube so as to be rotatable about the axis of the outer tube, so that the inner tube and the outer tube do not interfere with each other. The inner tube and the drilling head can be smoothly rotated.

It is the schematic of the drilling rod of 1st Embodiment of the jet stirring apparatus by this invention. It is an expanded sectional view of the extension unit of a 1st embodiment. It is CC sectional view taken on the line of FIG.2 and FIG.7. It is the DD sectional view taken on the line of FIG.2 and FIG.7. It is the EE sectional view taken on the line of FIG. It is an expanded sectional view of the connection state of extension units of a 1st embodiment, and the connection state of a head unit and an extension unit. It is an expanded sectional view of the head unit of a 1st embodiment. It is the FF sectional view taken on the line of FIG. It is the GG sectional view taken on the line of FIG. It is the HH sectional view taken on the line of FIG. It is an expanded sectional view of the extension unit of the drilling rod of 2nd Embodiment of the jet stirring apparatus by this invention. It is the II sectional view taken on the line of FIG.11 and FIG.16. It is the JJ sectional view taken on the line of FIG.11 and FIG.16. It is the KK sectional view taken on the line of FIG. It is an expanded sectional view of the connection state of extension units of a 2nd embodiment, and the connection state of a head unit and an extension unit. It is an expanded sectional view of the head unit of a 2nd embodiment. It is the LL sectional view taken on the line of FIG. It is the MM sectional view taken on the line of FIG. It is the NN sectional view taken on the line of FIG. It is explanatory drawing which showed the procedure of the ground improvement method by this invention. It is explanatory drawing which showed the curve direction of the drill rod. It is explanatory drawing which showed the other procedure of the ground improvement method by this invention. It is explanatory drawing which showed the other procedure of the ground improvement method by this invention. It is the schematic which showed an example of the conventional ground improvement method. It is the schematic which showed the other example of the conventional ground improvement method. It is the schematic which showed the other example of the conventional ground improvement method. It is the schematic which showed the other example of the conventional ground improvement method, Comprising: It is explanatory drawing which showed the relationship between a casing and a monitor, Comprising: It is explanatory drawing which showed the initial state of insertion of a monitor. It is explanatory drawing which showed the state of the latter period of insertion of the monitor of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 10 show a first embodiment of a jet stirring apparatus according to the present invention. As shown in FIGS. 20, 22, and 23, the jet agitating apparatus 1 according to the present embodiment is effective for improving the ground 41 directly under the existing structure 40.

  That is, as shown in FIGS. 1 to 10, the jet agitating apparatus 1 according to the present embodiment is an inner tube 15 and an inner tube that is rotatably inserted around the axis of the outer tube 15 inside the outer tube 15. A drilling rod 2 comprising a pipe 20 and a drilling head 5 that is integrally provided at the tip of the inner pipe 20 and is rotatable integrally with the inner pipe 20 is provided, and the drilling liquid is discharged to the drilling head 5. Discharge holes 12 and injection holes 13 for injecting the solidified material at a high pressure are provided.

  As shown in FIG. 1, the drilling rod 2 is composed of a head unit 3 having a drilling head 5 at the tip and at least one extension unit 4 removably connected to the rear end of the head unit 3. One or more extension units 4 are connected to the rear end of the head unit 3 according to the length of the hole drilled in the ground 41.

  As shown in FIGS. 2 to 6, the extension unit 4 has a single outer tube 16 formed of a flexible material, and a flexibility that is rotatably inserted inside the single outer tube 16. The single inner tube 21 made of a material and a pair of bearings 35 and 35 that support the single inner tube 21 rotatably about the axis of the single outer tube 16 are configured. Various rolling bearings can be used for the bearing 35. In the present embodiment, a ball bearing is used for the bearing 35.

  As shown in FIGS. 2 and 3, bearing support portions 19 that project annularly inward in the radial direction are integrally provided on the inner surfaces of both ends in the axial direction of the single outer tube 16. Bearing support portions 25 projecting radially outward in an annular shape are integrally provided on the outer surface sides of both ends in the direction, and the single inner tube 21 is rotatable between the bearing support portion 19 and the bearing support portion 25. The bearing 35 which supports is interposed.

  As shown in FIGS. 2 and 3, the bearing support portion 25 of the single inner tube 21 is provided with four fan-shaped openings 26 penetrating the bearing support portion 25 in the axial direction. A cylindrical space 30 formed between the inner peripheral surface of the single outer tube 16 and the outer peripheral surface of the single inner tube 21 penetrates in the axial direction of the extension unit 4. The space 30 of the extension unit 4 and the space 30 and space 7 of the head unit 3 described later constitute a first supply path 32 described later.

  As shown in FIGS. 2 to 6, a cylindrical space 22 that penetrates the extension unit 4 in the axial direction is provided on the inner peripheral surface side of the single inner tube 21, and this space 22 and a head unit 3 described later are provided. The space 22 constitutes a second supply path 33 described later.

  As shown in FIGS. 2, 4, and 5, the outer peripheral surface of the portion outside the bearing support portion 19 at one end in the axial direction of the single outer tube 16 is formed in a predetermined male screw portion 17, and the bearing at the other end The inner peripheral surface of the portion outside the support portion 19 is formed in a predetermined female thread portion 18, and the outer peripheral portion of the single inner tube 21 at one end in the axial direction of the single inner tube 21 is hexagonal in cross section. Formed in the tapered cylindrical concave fitting portion 23, and the outer portion of the other end of the bearing support portion 25 is formed in the tapered cylindrical convex fitting portion 24 having a hexagonal cross section. Yes.

  As shown in FIG. 6, the two extension units 4, 4 are opposed to each other with their axes aligned, and the female thread portion 18 of the single outer tube 16 of one extension unit 4 and the single outer tube 16 of the other extension unit 4. By screwing the male thread portion 17 together, the convex fitting portion 24 of the single inner tube 21 of one extension unit 4 and the concave fitting portion 23 of the single inner tube 21 of the other extension unit 4 are mutually connected. The two extension units 4 and 4 are connected to each other, the space 30 and the space 30 of the extension units 4 and 4 communicate with each other, and the space 22 and the space 22 communicate with each other.

  As shown in FIGS. 7 to 10, the head unit 3 has a cylindrical portion formed of a steel pipe or the like whose front end is obliquely cut at a predetermined angle and whose rear end is closed by a disk-shaped base 9. 6 and a drilling head 5 consisting of an elliptical plate-shaped tip bit 8 that closes the tip of the cylindrical part 6 that is cut obliquely, and a rear end side of the base 9 of the cylindrical part 6 of the drilling head 5 A single inner tube 21 that is integrally connected with the center line aligned with the axis, a single outer tube 16 that is provided on the outer peripheral side of the single inner tube 21 so as to surround the single inner tube 21, and a single inner tube 21 Is formed of a pair of bearings 35 and 35 that rotatably support the axis of the single outer tube 16, and a discharge hole 12 is provided on the distal end side of the cylindrical portion 6 of the drilling head 5. An injection hole 13 is provided in the base 9 on the rear end side.

  The single outer tube 16 and the single inner tube 21 of the head unit 3 are formed of a flexible material, like the single outer tube 16 and the single inner tube 21 of the extension unit 4.

  As shown in FIG. 7 and FIG. 9, a bearing support portion 10 that protrudes annularly toward the rear side in the axial direction is integrally provided at the rear end of the base portion 9 of the cylindrical portion 6 of the drilling head 5 of the head unit 3. At the tip of the single outer tube 16, a bearing support portion 19 ′ that protrudes annularly toward the front side in the axial direction and whose outer peripheral surface faces the inner peripheral surface of the bearing support portion 10 of the base 9 is integrally provided. A bearing 35 is interposed between the inner peripheral surface of the bearing support 10 and the outer peripheral surface of the bearing support 19 ′. The single outer tube 16 and the single inner tube on the rear end side of the bearing 35 and the head unit 3. The single inner tube 21 is supported by the bearing 35 interposed between the first outer tube 21 and the single outer tube 16 so as to be rotatable about the axis of the single outer tube 16.

  As shown in FIG. 7, the bearing support portion 19 on the rear end side of the single outer tube 16 of the head unit 3, the bearing support portion 25 on the rear end side of the single inner tube 21, and the both bearing support portions 19, 25 are interposed. The bearing 35, the female thread portion 18 on the rear end side of the single outer tube 16, and the convex fitting portion 24 on the rear end side of the single inner tube 21 are configured in the same manner as those of the extension unit 4.

  As shown in FIGS. 7 and 8, the base 9 of the head unit 3 is provided with two semicircular openings 11 and 11 that pass through the base 9 in the axial direction symmetrically about an injection hole 13 to be described later. The space 7 inside the cylindrical portion 6 of the head unit 3 and the space 30 between the single outer tube 16 and the single inner tube 21 communicate with each other through the openings 11 and 11. The space 30 and the space 30 of the extension unit 4 described above constitute a first supply path 32 that supplies a drilling liquid such as bentonite solution to the discharge holes 12 of the head unit 3.

  As shown in FIGS. 7 and 8, an injection hole 13 that penetrates the base 9 in a direction perpendicular to the axis is provided in the base 9 of the head unit 3, and the inside of the single inner tube 21 is formed in the injection hole 13. A second supply path for supplying a solidified material such as grout or cement milk to the injection hole 13 of the head unit 3 through the space 22 of the head unit 3 and the space 22 of the extension unit 4 described above. 33 is configured.

  As shown in FIG. 6, the extension unit 4 is opposed to the rear end side of the head unit 3 in a state where the axes coincide with each other, and the female thread portion 18 of the single outer tube 16 on the rear end side of the head unit 3 and the front end of the extension unit. The single outer tube 16 male threaded portion 17 on the side is screwed together, so that the convex fitting portion 24 of the single inner tube 21 on the head unit 3 side and the concave fitting portion of the single inner tube 21 on the extension unit 4 side are provided. 23, the extension unit 4 is connected to the rear end side of the head unit 3, the space 30 of the extension unit 4 and the space 30 of the head unit 3 communicate with each other, and the space 22 of the extension unit 4 is connected. And the space 22 of the head unit 3 communicate with each other, and a series of first supply paths 32 that communicate with the ejection holes 12 of the head unit 3 and a series of second supply paths 33 that communicate with the ejection holes 13 are configured.

  By extending the drilling rod 2 having the above configuration toward the ground 41 and discharging the drilling liquid from the discharge hole 12 of the drilling head 5, the drilling head 5 is rotated and pushed into the ground 41, The ground 41 can be drilled linearly. Further, in the middle of the drilling, the rotation of the drilling head 5 is stopped, and the drilling rod 2 is pushed into the ground 41, so that the drilling head 5 is moved as shown in FIG. 1, FIG. 7, and FIG. Since the tip bit 8 at the tip is inclined, a resistance force acts on the tip bit 8 from the ground 41 from the direction of the arrow in FIG. 21, and the traveling direction of the drill rod 2 in the direction A in FIG. Be changed. Accordingly, the rotation of the drilling head 5 is stopped, the drilling rod 2 is pushed into the ground 41, the direction of the tip bit 8 is adjusted, and the rotation of the drilling head 5 is restarted to adjust the direction of the hole 43. And the traveling direction of the drilling rod 2 can be adjusted.

  In order to improve the ground 41 directly under the existing structure 40 using the jet stirring device 1 of the present embodiment configured as described above, for example, as shown in FIG. The ground machine 1a is installed on the ground, the drilling rod 2 is connected to the ground machine 1a, the drilling rod 2 is fed out from the ground machine 1a, and the drilling hole 12 is drilled from the ground machine 1a through the first supply path 32. While the liquid is supplied and the drilling liquid is discharged from the discharge hole 12, the drilling head 5 is rotated and pushed into the ground 41, so that the ground 41 is linearly drilled obliquely downward, and the drill rod 2 The tip is made to reach a depth corresponding to the improvement target region 42 immediately below the existing structure 40.

  In this case, the extension unit 4 is sequentially connected to the rear end of the head unit 3 of the drilling rod 2, while the length of the drilling rod 2 is successively extended and pushed into the ground 41, whereby the tip of the drilling rod 2 is moved. A depth corresponding to the improvement target region 42 immediately below the existing structure 40 is reached.

  Then, the rotation of the drilling head 5 is temporarily stopped, and if necessary, the drilling rod 2 is further pushed in while connecting the extension unit 4, and the resistance force from the ground 41 by the tip bit 8 at the tip of the drilling head 5. Accordingly, as shown in FIG. 20, the direction of the drill rod 2 is gradually changed toward the improvement target region 42. Then, by resuming the rotation of the drilling head 5, the tip of the drilling rod 2 reaches the improvement target region 42, and by further pushing the drilling rod 2, the tip of the drilling rod 2 is improved. To reach a position penetrating through.

  Then, the drilling head 5 is rotated while pulling out the drilling rod 2 from the position penetrating the improvement target region 42, and the solidification material is supplied to the injection hole 13 through the second supply path 33, and the surroundings are formed from the injection hole 13 The ground 41 in the improvement target region 42 and the solidified material are agitated and mixed by injecting the solidification material toward the ground 41 at a high pressure, and the solidification material is injected into the ground 41 in the improvement target region 42.

In this way, the improvement target region 42 of the ground 41 directly below the existing structure 40 can be improved by injecting the solidified material by high-pressure injection into the entire ground 41 of the improvement target region 42.
At this time, surplus mud produced by drilling the ground 41 is discharged to the ground on the starting side through the gap between the drilled hole 43 and the drilling rod 2.

  In addition to the above procedure, as shown in FIG. 22, the drilling rod 2 is pushed to a position where the tip reaches the improvement target region 42, and the drilling head 5 is rotated at that position while discharging the holes 12. Then, the drilling liquid is discharged from the injection hole 13 and the solidification material is injected from the injection hole 13 at a high pressure to push the drilling rod 2 in a direction penetrating the improvement target region 42, and the ground 41 and the solidification material around the drilling rod 2 are moved. The improvement target region 42 may be ground improved by stirring and mixing and injecting a solidifying material into the ground 41 of the improvement target region 42.

  Further, as shown in FIG. 23, the drilling rod 2 is pushed to a position penetrating the improvement target region 42, and the direction of the drilling rod 2 is changed obliquely upward from that position to penetrate the ground, and the drilling is performed from that position. The hole rod 2 is pulled out until the tip reaches the tip of the improvement target region 42 (the right end in FIG. 23), and the drilling rod 5 is further rotated from the position, and the drilling head 5 is rotated to remove the solidified material from the injection hole 13. The solidified material is injected into the surrounding ground 41 while agitating and mixing the ground 41 and the solidified material around the drilling rod 2 with high pressure injection, and the drilled rod 2 is further pulled out to end the improvement target region 42 (FIG. 23). The left solid end of the improvement target region 42 may be injected into the ground 41 of the improvement target region 42 to improve the improvement target region 42.

  In this case, the excess mud produced by drilling the ground 41 is discharged to the ground on the arrival side through the hole 43 that has been drilled, so that the excess mud can be easily discharged.

  In the jet agitating apparatus 1 of the present embodiment configured as described above, the outer tube 15 and the inner tube 20 of the drilling rod 2 are formed of a flexible material. As shown in the figure, when the existing structure 40 such as a road or a railway that needs to be turned around or the ground 41 directly under the existing structure 40 such as an LNG tank that cannot be turned around is improved, turning is necessary. Without the need to destroy the existing structure 40, the tip of the drilling rod 2 reaches the area 42 to be improved directly under the existing structure 40, and a solidified material is injected into that portion to improve the ground. can do.

  Further, even when an obstacle such as a foundation or a pile exists in the ground 41 directly under the existing structure 40, the tip of the drilling rod 2 reaches the back side of the obstacle and is solidified on the back side of the obstacle. The material can be injected and the ground can be improved.

  Furthermore, as shown in FIG. 26, since it is not necessary to drill a vertical shaft along the existing structure 40, even if the improvement target region 42 for ground improvement is located at a deep position, a large vertical shaft is required. It is not necessary to drill a pit, and the ground improvement can be easily performed in a short time without much cost.

  Further, since the drilling rod 2 is constituted by the head unit 3 and at least one extension unit 4 detachably connected to the rear end of the head unit 3, the length of the drilling rod 2 is cut into the ground 41. It can be easily set to a length corresponding to the length of the hole.

  Further, since the head unit 3 and the extension unit 4 constituting the drilling rod 2 support the single inner tube 21 rotatably with bearings 35 inside the single outer tube 16, the drilling rod 2 is attached to the ground 41. Even if the single outer tube 16 of the head unit 3 and the extension unit 4 is bent during the pushing-in process, the single inner tube 21 does not interfere inside the single outer tube 16, and the rotation of the single inner tube 21 is obstructed. The hole drilling head 5 of the head unit 3 can be smoothly rotated, and the hole 43 toward the improvement target region 42 can be easily and reliably drilled in the ground 41.

  Furthermore, since many processes like the ground improvement method of patent document 1 are not required, ground improvement can be performed easily in a short time without spending a great expense.

  Further, the head unit 3 of the drilling rod 2 has a simple configuration in which a rear end of the drilling head 5 is connected to a single inner tube 21 that is rotatably supported by a bearing 35 inside the single outer tube 16. In addition, the extension unit 4 has a simple configuration in which the single inner tube 21 is rotatably supported by the bearing 35 inside the single outer tube 16, so that the entire configuration can be simplified.

  Further, the head unit 3 and the extension unit 4 are connected by screwing the male screw portion 17 of the single outer tube 16 of the extension unit 4 into the female screw portion 18 of the single outer tube 16 of the head unit 3. The convex fitting part 24 of the inner pipe 21 and the concave fitting part 23 of the extension unit 4 may be fitted together, and the extension units 4 are connected to each other by the single outer pipe 16 of one extension unit 4. The male screw portion 17 of the single outer tube 16 of the other extension unit 4 is screwed into the female screw portion 18 so that the convex fitting portion 24 of the single inner tube 21 of one extension unit 4 and the single inner portion of the other extension unit 4 are combined. Since the concave fitting portion 23 of the tube 21 may be fitted, the length of the drilling rod 2 can be easily adjusted, and the drilling operation can be performed efficiently.

11 to 18 show a second embodiment of the jet stirring apparatus according to the present invention.
In the jet agitating apparatus 1 of the present embodiment, the single inner pipe 21 of the head unit 3 and the extension unit 4 is provided with a first single inner pipe 27 and a second single inner pipe 28 provided inside the first single inner pipe 27. And a third supply path 34 is formed by a circular space 31 between the first single inner pipe 27 and the second single inner pipe 28, and the base 9 of the head unit 3 As shown in FIG. 16, a cylindrical auxiliary injection hole 14 is provided around the injection hole 13 so as to surround the injection hole 13, and a third supply path 34 is communicated with the auxiliary injection hole 14 to provide a third supply. A fluid (a gas such as air or a liquid such as water) is supplied to the reinforcing injection hole 14 via a passage 34, and the other configurations are the same as those described in the above embodiment.

  And even if it exists in the jet stirring apparatus 1 of this Embodiment, there exists an effect similar to what is shown in the said embodiment, and when the solidification material is injected from the injection hole 13 at high pressure, the circumference | surroundings of the injection hole 13 are demonstrated. By injecting the fluid from the auxiliary injection holes 14, the friction between the solidified material injected at a high pressure from the injection holes 13 and the surrounding ground 41 can be reduced. A wide area of the ground 41 in the region 42 can be agitated and mixed with the solidified material, and the solidified material can be injected and strengthened in a wide area of the ground in the improved region 42.

DESCRIPTION OF SYMBOLS 1 Injection stirrer 1a Ground machine 2 Drilling rod 3 Head unit 4 Extension unit 5 Drilling head 6 Cylindrical part 7 Space 8 Tip bit 9 Base 10 Bearing support part 11 Opening 12 Discharge hole 13 Injection hole 14 Auxiliary injection hole 15 Out Pipe 16 Single outer pipe 17 Male thread part 18 Female thread part 19 Bearing support part 19 'Bearing support part 20 Inner pipe 21 Single inner pipe 22 Space (inside of inner pipe)
23 concave fitting portion 24 convex fitting portion 25 bearing support portion 26 opening 27 first single inner tube 28 second single inner tube 30 space (between outer tube and inner tube)
31 space (between the first inner pipe and the second inner pipe)
32 First supply path 33 Second supply path 34 Third supply path 35 Bearing 40 Existing structure 41 Ground 42 Area to be improved 43 Hole 45 Casing 46 Monitor

Claims (9)

An outer tube formed of a material having a flexible material; and an inner tube formed of a material having a flexible material that is rotatably supported around the axis of the outer tube in the outer tube; A drilling rod that is provided at the tip of the inner tube and is rotatable integrally with the inner tube, and a discharge hole for discharging a drilling liquid provided at the tip of the drilling head of the drilling rod An injection hole for injecting a solidified material provided behind the discharge hole of the drilling head, a first supply path for supplying a drilling liquid to the discharge hole, and supplying the solidification material to the injection hole and a second supply passage for,
It said inner tube extends concentrically over the inner side of the outer tube to the entire length, injection stirring apparatus characterized that you have is rotatably supported at a plurality of positions. The distal end of the prior SL drilling head, ejecting stirrer according to claim 1, the distal end bit inclined at a predetermined angle relative to the axis of the inner tube and being provided integrally.   The injection according to claim 1, wherein the first supply path is provided between the outer pipe and the inner pipe, and the second supply path is provided inside the inner pipe. Stirring device.   The inner pipe includes a first inner pipe and a second inner pipe provided inside the first inner pipe, and the first supply path is provided between the first inner pipe and the outer pipe. The second supply path for supplying the solidification material to the injection hole is provided inside the second inner pipe, and the periphery of the injection hole is between the first inner pipe and the second inner pipe. The jet stirring device according to claim 3, wherein a third supply path for supplying fluid to an auxiliary jet hole provided so as to surround the jet hole is provided. The drilling rod includes a single outer tube, a single inner tube rotatably supported inside the single outer tube via a bearing, and connecting means provided at both ends of the single outer tube and the single inner tube. An extension unit consisting of
A single outer pipe, a single inner pipe rotatably supported inside the single outer pipe via a bearing, the single outer pipe and the drilling head provided at one end of the single inner pipe, and the single outer pipe. A head unit comprising an outer tube and a connecting means provided at the other end of the single inner tube,
The jet agitating device according to any one of claims 1 to 4, wherein at least one extension unit is connected to the head unit in series via the connecting means.   The jet agitation according to claim 5, wherein the connecting means comprises a combination of a screw portion provided at an end portion of the single inner tube and a fitting portion provided at an end portion of the single inner tube. apparatus. A ground improvement method for improving the ground directly under an existing structure using the jet agitating device according to any one of claims 1 to 6,
From the ground on the side of the existing structure, the ground is drilled diagonally downward with the drilling rod, and the tip of the drilling rod reaches the depth corresponding to the improvement target area of the ground directly under the existing structure. Drilling step for reaching the position penetrating the improvement target region while changing the direction of the drilling rod toward the improvement target region,
A solidifying material injecting step of injecting the solidifying material into the improvement target region by injecting a solidifying material from the injection hole while pulling out the drilling rod and, if necessary, injecting a fluid from the auxiliary injection hole; A ground improvement method characterized by comprising: A ground improvement method for improving the ground directly under an existing structure using the jet agitating device according to any one of claims 1 to 6,
From the ground on the side of the existing structure, the ground is drilled diagonally downward with the drilling rod, and the tip of the drilling rod reaches the depth corresponding to the improvement target area of the ground directly under the existing structure. A drilling step of causing the tip of the drilling rod to reach the improvement target region while changing the direction of the drilling rod toward the improvement target region;
The hole drilling liquid is discharged from the discharge hole, the solidified material is sprayed from the injection hole, and the drilling rod is further advanced while the fluid is sprayed from the auxiliary injection hole as necessary, and the improvement object A ground improvement method comprising: a solidifying material injecting step for injecting a solidifying material into the region. A ground improvement method for improving the ground directly under an existing structure using the jet agitating device according to any one of claims 1 to 6,
From the ground on the side of the existing structure, the ground is drilled diagonally downward with the drilling rod, and the tip of the drilling rod reaches the depth corresponding to the improvement target area of the ground directly under the existing structure. While changing the direction of the drilling rod toward the improvement target region, the tip of the drilling rod reaches a position penetrating the improvement target region, and the direction of the drilling rod is directed obliquely upward Drilling step of changing the tip of the drilling rod to the ground while changing,
A solidifying material injecting step of injecting the solidifying material into the improvement target region by injecting a solidifying material from the injection hole while pulling out the drilling rod and, if necessary, injecting a fluid from the auxiliary injection hole; A ground improvement method characterized by comprising:

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