JP6710166B2 - Rotary nozzle, ground improvement apparatus and ground improvement method using the rotary nozzle - Google Patents

Description

The present invention relates to a rotary nozzle for injecting a fluid such as cement slurry into the ground at a high pressure, a ground improvement apparatus using the rotary nozzle, and a ground improvement method.

As a ground improvement device for injecting this kind of cement slurry into the ground to create an improved body, there is one shown in FIG. 17 (see, for example, Patent Document 1).

As shown in FIG. 17, this ground improvement device 1 is composed of a conventional backhoe and a power shovel, and is for excavating and improving soft ground, and a boom 3 attached to a main body 2 that can travel. And an arm 4 attached to the boom 3 and a bucket 5 attached to the tip of the arm 4. A first nozzle member 6 and a second nozzle member 7 are provided on the base end side inside the bucket 5.

Then, the bucket 5 is moved inside the ground 8 in a state of being submerged in the ground 8, and the pressurized gas and the solidifying material slurry are injected from the respective injection holes of the first nozzle member 6 and the second nozzle member 7. As a result, the lump of soil in the bucket 5 is finely pulverized by the injection of the pressurized gas while being agitated and kneaded with the solidifying material slurry for improvement.

JP, 2016-56588, A JP, 10-311024, A

However, in the conventional ground improvement device 1, the pressurized gas and the solidifying material slurry are respectively jetted in one direction from the nozzle members 6 and 7 provided in the bucket 5 attached to the tip of the arm 4. Only a certain range could be improved. In addition, since the bucket 5 has a limited range of submersion into the ground 8, for example, it was difficult to improve the ground immediately below the existing structure in the ground 8.

Therefore, the present invention has been made to solve the above-mentioned problems, and a rotary nozzle capable of easily and surely widening a drilling (unraveling) range and an improvement range of the ground and a ground improvement using the rotary nozzle. An object is to provide an apparatus and a ground improvement method.

The rotary nozzle used in the ground improvement device that performs high-pressure injection of the fluid from the injection nozzle into the ground of the present invention to improve the hole and the ground is a main fluid passage through which the fluid flows to the center of the projecting shaft portion. A holder as a fixed portion formed, a sub-fluid passage communicating with the main fluid passage is formed, and a rotating body as a rotating portion that is rotated about the shaft portion of the holder by a reaction force of the fluid ejection force. the provided, more to the rotating body, radially towards the the outer circumferential side of the injection hole communicating with the auxiliary fluid passage from the sub fluid passage by a predetermined angle inclined obliquely to the outside of a vertical plane against the main fluid passage The injection nozzle is attached to at least one of the tip openings of the plurality of injection holes, a blocking plug is attached to the tip openings of the other injection holes, and the tip of the shaft portion of the main fluid passage of the holder is formed first. An end opening is formed, an injection nozzle is attached to the tip opening, and the rotating body is rotated by the reaction force of the ejection force of the fluid ejected from the injection nozzle attached to the tip opening of the injection hole around the injection nozzle. The point is that you made it freely.

According to the rotary nozzle used in the ground improvement device of the present invention, the holder is provided with a holder as a fixed part, and a rotary body as a rotary part that rotates around the shaft part of the holder by the reaction force of the fluid ejection force. an injection nozzle attached to the tip opening of the main fluid passage extends to parts and the fluid from the injection nozzle attached to the tip opening of the inclined injection holes to the main flow fluid path of the rotating body so as to high-pressure injection by, it is possible to high-pressure injection fluid in a straight line from the injection nozzle at the tip of the shaft portion of the holder, to be high-pressure injection fluid in a spiral shape from the inclined injection Ino nozzle on the outer peripheral surface of the rotary body it can. As a result, drilling and improvement of the ground can be performed easily and reliably over a wide range.

It is a side view of the ground improvement device of a 1st embodiment of the present invention. It is sectional drawing of the expandable body attached to the movable part of the said soil improvement apparatus. It is sectional drawing of the rotary nozzle attached to the front-end|tip of the said expansion-contraction body. It is a front view of the said rotary nozzle. It is sectional drawing which follows the YY line in FIG. It is explanatory drawing which shows the rotation principle of the said rotary nozzle. It is explanatory drawing which shows the state during the ground improvement of the said ground improvement apparatus. It is a perspective view showing the important section of the above-mentioned ground improvement device in the state during ground improvement. It is sectional drawing of the other form of the said rotary nozzle. It is sectional drawing of another form of the said rotary nozzle. It is a front view of another form of the above-mentioned rotary nozzle. (A) It is sectional drawing of another form of the said rotary nozzle, (b) is a front view of the injection nozzle of the same rotary nozzle. It is sectional drawing which follows the XX line in FIG. 12 (a). It is sectional drawing which follows the ZZ line in Fig.12 (a). It is explanatory drawing which shows the state just before ground improvement of the ground improvement apparatus of 2nd Embodiment of this invention. It is explanatory drawing which shows the state during ground improvement of the ground improvement apparatus of the said 2nd Embodiment. It is a side view of the conventional ground improvement apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a side view of a ground improvement device according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of an expandable body attached to a movable part of the device, and FIG. 3 is a cross-section of a rotary nozzle attached to the tip of the expandable body. FIG. 4, FIG. 4 is a front view of the rotary nozzle, FIG. 5 is a cross-sectional view taken along the line YY in FIG. 3, FIG. 6 is an explanatory view showing the principle of rotation of the rotary nozzle, and FIG. 7 is a ground improvement of the device. FIG. 8 is a perspective view showing a main part of the apparatus in a state during ground improvement.

As shown in FIGS. 1 and 7, the ground improvement device 10 uses a pile driving machine or the like as a base machine to feed water or cement slurry (solidifying material slurry) from a rotary nozzle 40 provided in a lifting casing (movable part) 18 thereof. A fluid S such as is injected into the ground 8 at a high pressure for drilling and improving the ground 8, and a traveling machine 11 provided with a crawler and the like, and a turning machine mounted on the traveling machine 11 so as to be freely rotatable. 12 and 12. A leader 14 is pivotally supported by a swivel machine 12 via a leader support 13 so that a hoisting cylinder 15 can perform hoisting operation. A guide pipe (not shown) and a rack 16 are integrally formed on the front surface of the leader 14, and an auger machine 17 engages with the guide pipe and engages with the rack 16 to move up and down along the leader 14 by rotation of a pinion (not shown). It is supposed to do. The lower side of the elevating casing 18 that is moved up and down by the auger machine 17 is held by a lower guide 19 so as to maintain the vertical direction.

As shown in FIGS. 1 and 2, a telescopic body 20 that expands and contracts in the horizontal direction is attached to the lower end (tip) 18a of the elevating casing 18. The expandable body 20 has a large-diameter cylindrical body 21 closed at a base end opening 21a side with a lid body 22 and a center connected to a lower end 18a of the elevating casing 18, and slidable in the large-diameter cylindrical body 21. A medium-diameter cylindrical body 23 that is inserted and retained, and a small-diameter cylindrical body 24 that is closed at the tip opening 24b side with a lid 25 and is slidably inserted into the medium-diameter cylindrical body 23 and retained. It is composed of. Inside each of the cylinders 21, 23, 24 is a fluid passage 26 through which the fluid S flows. Further, a pipe 30 connected to a water tank and a plant for generating cement slurry (both not shown) is connected to a fluid supply port 21c formed in the center of the large-diameter cylindrical body 21, and each cylindrical body is connected. A fluid S such as water or cement slurry is switched and supplied into the insides of 21, 23 and 24. Then, due to the fluid pressure of the fluid S flowing through the fluid passages 26 of the respective cylindrical bodies 21, 23, 24, the medium diameter cylindrical body 23 and the small diameter cylindrical body 24 are extended with respect to the large diameter cylindrical body 21. ing. It should be noted that the water is supplied from the water tank or the plant to the pipe 30 while being pressurized to a high pressure (for example, a pressure of 60 kgf/cm ² ) by a pump (not shown).

Further, as shown in FIG. 2, a wire insertion hole 22a is formed at the center of the lid 22 of the large-diameter cylindrical body 21, and the tip 31a of the wire 31 inserted through the wire insertion hole 22a has a small diameter. It is connected to a swivel mechanism 32 attached to the inner surface of the lid 25 of the cylindrical body 24. This wire 31 is wound by an electric winch 36 attached to the elevating casing 18 via a bracket 35 via a turn sheave 34 attached to the outer surface of the lid 22 of the large-diameter cylindrical body 21 via a bracket 33. It is supposed to be taken. When the wire 31 is wound by the electric winch 36 in a state where the medium-diameter cylindrical body 23 and the small-diameter cylindrical body 24 are extended with respect to the large-diameter cylindrical body 21, the large-diameter cylindrical body 21 is wound. The medium diameter cylindrical body 23 and the small diameter cylindrical body 24 are contracted so that the medium diameter cylindrical body 23 and the small diameter cylindrical body 24 are accommodated in the large diameter cylindrical body 21. Further, as shown in FIG. 3, a screw hole 25a is formed at the center of the lid 25 of the small-diameter cylindrical body 24, and the outer surface of the lid 25 of the small-diameter cylindrical body 24 is formed through the screw hole 25a. A rotary nozzle 40 that rotates by the reaction force of the jetting force of the fluid S is attached.

As shown in FIGS. 3, 4, and 5, the rotary nozzle 40 includes a holder (fixed portion) 41 having a main fluid passage (fluid passage) 43 through which the fluid S flows and a shaft portion 42 protruding to the center. A sub-fluid passage (fluid passage) 53 communicating with the main fluid passage 43 is formed, and is configured by a rotating body (rotating portion) 51 that is rotated around the shaft portion 42 of the holder 41 by the reaction force of the jetting force of the fluid S. Has been done.

The holder 41 is formed in a large-diameter columnar shape, and a small-diameter columnar shaft portion 42 is integrally formed in the center of the front surface of the holder 41 so as to project therefrom. A rotating body 51 is rotatably supported on the shaft portion 42 via a ball bearing 45 and a pair of dry bearings 46, 46.

The main fluid passage 43 of the holder 41 is composed of a large diameter surface portion 43a having a screw hole formed on the inner peripheral surface from the bottom surface side of the holder 41, a conical surface portion 43b, and a small diameter surface portion 43c formed on the shaft portion 42 side. ing. A screw portion 47a formed on the front side of the outer peripheral surface of the cylindrical connecting cylinder body 47 is screwed into the screw hole of the large diameter surface portion 43a. Further, the screw portion 47 b formed on the rear side of the outer peripheral surface of the cylindrical connecting cylinder body 47 is screwed into the screw hole 25 a of the lid body 25 of the small-diameter cylinder body 24 of the expandable body 20. As a result, the fluid S of water or cement slurry is supplied from the fluid passage 26 in the expandable body 20 to the main fluid passage 43 of the holder 41.

Further, as shown in FIGS. 3 and 5, four communication passages 44 communicating with the auxiliary fluid passage 53 of the rotating body 51 are formed in a cross shape in the middle of the small diameter surface portion 43c of the main fluid passage 43. Further, as shown in FIG. 3, a tip end port 43d, which is a screw hole, is formed at the tip end of the main fluid passage 43 formed up to the shaft portion 42, and the injection nozzle 48 is attached to this tip end port 43d. Has been.

The rotating body 51 is formed in a columnar shape having the same diameter as the outer diameter of the holder 41, and a center hole 52 having a circular cross section through which the shaft portion 42 of the holder 41 is inserted is formed in the center thereof.

As shown in FIGS. 3 to 5, the sub-fluid passage 53 of the rotating body 51 includes an annular passage 53a that communicates with the main fluid passage 43 of the holder 41 through four communication passages 44, and an outer peripheral side of the annular passage 53a. And three branch passages 53b that are radially formed toward each other. As shown in FIG. 3, a pair of annular recesses 52a, 52a are formed in the center hole 52 of the rotating body 51 so as to sandwich the annular passage 53a of the sub-fluid passage 53. The fitted seal ring 54 prevents the fluid S from leaking from the annular passage 53a. Further, the tip end of each branch passage 53b is closed with a closing plug 55A.

Further, as shown in FIGS. 3 and 4, in the rotating body 51, injection holes (fluid passages) 56 communicating with the respective branch passages 53 b of the sub fluid passage 53 are three-dimensionally predetermined with respect to the main fluid passage 43. Three sub-fluid passages 53 are radially formed from each branch passage 53b of the sub-fluid passage 53 inclining at an angle θ. As shown in FIG. 5, the base end port 56b of the injection hole 56 is connected to the branch passage 53b.

Further, as shown in FIGS. 3 and 4, the rotating body 51, a vertical surface injection holes (fluid passage) 56 communicating with the branch passages 53b of the auxiliary fluid passage 53 against the main fluid passage 43 is horizontal Three sub-fluid passages 53 are radially formed from the respective branch passages 53b of the sub-fluid passage 53 toward the outer peripheral side in a three-dimensional inclined manner by a predetermined angle θ. As shown in FIG. 5, the base end port 56b of the injection hole 56 is connected to the branch passage 53b.

Further, as shown in FIGS. 3 and 4, each of the three injection holes 56 of the rotating body 51 has a tip end port 56a formed as a screw hole, and the one end port 56a is provided with an injection nozzle 58. A closing plug 55B is attached to the tip end port 56a of the remaining other injection hole 56.

Further, as shown in FIG. 3, on the front surface 41a side of the holder 41 and on the rear surface 51b side of the rotating body 51 opposed to the front surface 41a, a rotation sensor 60 for detecting the rotation state of the rotating body 51 is provided. The rotation sensor 60 includes a proximity switch 61 formed of a semiconductor MR element or the like mounted on the rear surface 51b side of the rotating body 51, and a plurality of sheet-shaped magnets (permanent magnets) mounted on the front surface 41a side of the holder 41 at equal intervals. ) 62 and. The rotation sensor 60 detects whether the rotating body 51 is rotating or is stopped, so that the rotating state of the rotating body 51 during ground improvement can be easily and surely confirmed.

As shown in FIG. 2, the end 21b of the distal end opening of the large-diameter cylindrical body 21 of the expandable body 20 is bent inward, and the end 23a of the proximal end opening of the medium-diameter cylindrical body 23 is outwardly bent. The end portion 23b of the tip opening of the medium-diameter cylindrical body 23 is bent inward, and the end portion 24a of the base end opening of the small-diameter cylindrical body 24 is bent outward to prevent coming off. Has been done. Further, a seal (not shown) is provided between the wire insertion hole 22a of the lid 22 of the large-diameter cylindrical body 21 of the telescopic body 20 and the wire 31, and between the respective ends of the three cylindrical bodies 21, 23, 24 that are prevented from coming off. It is sealed by a member or the like so that the fluid S does not leak outside.

According to the ground improvement device 10 of the first embodiment described above, as shown in FIG. 1, the expandable body 20 attached to the lower end 18a of the elevating casing 18 is inserted into the hole 8a formed in the ground 8 to a predetermined depth. The water S as a fluid is supplied from the pipe 30. Due to the water pressure at the time of discharging the water S from the pipe 30 into the expandable body 20, as shown in FIG. 7, the medium-diameter cylindrical body 23 and the small-diameter cylindrical body 23 with respect to the large-diameter cylindrical body 21 of the expandable body 20. 24 is drilled while extending horizontally. At this time, water S is jetted at high pressure (jet) while the jet nozzles 48 and 58 of the rotary nozzle 40 attached to the tip opening 24b of the small-diameter cylindrical body 24 rotate.

More specifically, the linear high-pressure jet water S1 is jet-jetted from the jet nozzle 48 of the shaft portion 42 of the holder 41 of the rotary nozzle 40, and the rotary body of the rotary nozzle 40 is centered on the linear high-pressure jet water S1. When the spiral (spiral) high-pressure jet water S2 is jet-jetted from the jet nozzle 58 inclined to the outer peripheral side of 51, the tip of the linear high-pressure jet water S1 becomes like the tip of the blade tip of a so-called twist drill. In addition to functioning, the spiral high-pressure jet water S2 functions like a spiral cutting edge of a so-called twist drill, so that the cavity directly below the existing structure 9 in the ground 8 from the side wall of the hole 8a of the ground 8. Up to 8b, it is possible to easily and reliably make a circular hole in a horizontal straight line. In addition, since the high-pressure jet water S1 is jetted in a spiral shape while the inclined jet nozzle 58 is rotated, the drilling (unraveling) range of the ground 8 is widened. Further, the widening of the hole-drilling range can contribute to the reduction of the tip resistance of the expandable body 20 even when the expandable body 20 expands and contracts in the horizontal direction, and also contributes to the rotation assist of the rotary nozzle 40. ..

Then, after the horizontal drilling of the side wall of the hole 8a of the ground 8, the cement slurry S as a fluid is switched and supplied from the pipe 30. Also in this case, the linear high-pressure injection cement slurry S1 is jet-injected from the injection nozzle 48 in the center of the rotary nozzle 40, and is inclined toward the outer peripheral side of the rotary nozzle 40 with the linear high-pressure injection cement slurry S1 as the center. Since the spiral high-pressure injection cement slurry S2 is jet-injected from the injection nozzle 58, the cement slurry S can be easily and reliably jet-injected into the cavity 8b directly below the existing structure 9 in the ground 8. The improved body K and the bottom surface of the existing structure 9 can be easily adhered by jetting the slurry S.

After the ground improvement immediately below the existing structure 9 in the ground 8, the wire 31 is wound by the electric winch 36 while the fluid S of the cement slurry is being drawn out from the stretched expandable body 20, thereby increasing the diameter of the expandable body 20. The medium-diameter cylindrical body 23 and the small-diameter cylindrical body 24 are retracted with respect to the cylindrical body 21, and the medium-diameter cylindrical body 23 and the small-diameter cylindrical body 24 are accommodated in the large-diameter cylindrical body 21. Next, the telescopic body 20 attached to the lower end 18a of the elevating casing 18 is pulled up from the hole 8a of the ground 8 to complete the lower (lower) ground improvement work. Then, by repeating this ground improvement work sequentially upward (upper side), as shown in FIG. 8, the improved body K is formed in a horizontally long dumpling shape up to immediately below the existing structure 9 in the ground 8 and directly below the existing structure 9. To improve the ground.

As described above, the expandable/contractible body 20 having the fluid passage 26 in which the fluid S of water or cement slurry flows therein is attached to the lower end 18a of the elevating casing 18 of the ground improvement apparatus 10 to expand and contract in the horizontal direction. A rotary nozzle 40 that rotates by the reaction force F′ of the jetting force F of the fluid S is attached to the tip of a small-diameter cylindrical body 24 of 20, and the expandable body 20 is jetted with high pressure from the jet nozzles 48 and 58 of the rotary nozzle 40. As shown in FIG. 1 and FIG. 7, when the hollow portion 8b is located directly below the existing structure 9 in the ground 8, the hollow portion immediately below the existing structure 9 can be expanded by the fluid pressure of It is possible to drill holes and improve the ground in a short time while extending the elastic body 20 horizontally up to 8b. Thereby, the drilling range and the improvement range of the ground 8 can be further widened.

Further, by utilizing the fluid pressure of the fluid S flowing through the fluid passage 26 in the elastic body 20, the medium-diameter cylindrical body 23 and the small-diameter cylindrical body 24 are horizontally arranged with respect to the large-diameter cylindrical body 21 of the elastic body 20. Since the drive source for extending the expandable/contractible body 20 is not required, the cost can be reduced accordingly.

Furthermore, the wire 31 having the tip 31a connected to the lid 25 of the small-diameter cylindrical body 24 of the expandable body 20 is wound by the electric winch 36, whereby the medium-diameter cylindrical body 23 of the expandable body 20 is wound. Therefore, the small-diameter cylindrical body 24 can be easily and surely retracted with respect to the large-diameter cylindrical body 21.

Further, the sub-fluid passage 53 of the rotating body 51 of the rotary nozzle 40 is connected to the main fluid passage 43 of the holder 41 by four communication passages 44, and an annular passage 53a is formed radially from the annular passage 53a toward the outer peripheral side. By forming three branch passages 53b formed in the holder 41 and connecting the base end port 56b of the injection hole 56 to each branch passage 53b, the fluid S of water or cement slurry is rotated from the main fluid passage 43 of the holder 41. The fluid S of water or cement slurry can be easily and reliably jetted from the jet nozzle 58 to the tip opening 56a of the jet hole 56 of the body 51 at a high speed.

FIG. 9 is a sectional view of another form of the rotary nozzle.

The rotary nozzle 40A of another form is formed so that the inclination angles θ and θ′ of the three injection holes 56 of the rotary body 51 with respect to the main fluid passage 43 of the holder 41 are different (θ<θ′). Accordingly, the fluid S of water or cement slurry can be jetted at high pressure from the jet nozzles 58 attached to the tip openings 56a of the jet holes 56 having different inclination angles θ and θ′. The area and improved area can be widened. Further, it is possible to widen the range of the improved body by jet injection of the cement slurry S which can be made once.

FIG. 10 is a sectional view of another form of the rotary nozzle, and FIG. 11 is a front view of the rotary nozzle.

In the rotating nozzle 40B of this another form, three injection holes 56 formed in the inner row on the same circumference of the rotating body 51 are arranged on the circumference of the rotating body 51 with a predetermined distance from the center of the rotating body 51 toward the outer peripheral side. Three more are formed in the outer row. As a result, the fluid S of water or cement slurry can be jetted at high pressure from the jet nozzles 58 attached to the tip openings 56a of the jet holes 56 located in two rows, the inner side and the outer side. The pore area and the improved area can be further widened. Moreover, the range of the improved body by jet injection of the cement slurry S that can be made once can be further widened.

FIG. 12A is a cross-sectional view of still another form of the rotary nozzle, FIG. 12B is a front view of an injection nozzle of the rotary nozzle of the other form, and FIG. 13 is a XX line in FIG. 12A. 14 is a sectional view taken along line ZZ in FIG. 12(a).

This rotary nozzle 40C of still another form has holes for the washers of the respective injection nozzles 48, 58 attached to the front end opening 43d of the main fluid passage 43 of the holder 41 and the front end opening 56a of the injection hole 56 of the rotating body 51. Air passages 48b and 58b for supplying the auxiliary air A are provided, and tip ends 48c and 58c of the air passages 48b and 58b are annular (rings) so as to surround the nozzle holes 48a and 58a of the injection nozzles 48 and 58. Shaped). Further, the air passages 48b and 58b communicate with the air supply passages 59 and 49 formed in the rotating body 51 and the holder 41, respectively. The tip end of each branch passage 53b of the sub-fluid passage 53 of the rotating body 51 is closed by a ring-shaped block-shaped closing body 55C, and the injection hole (communicating with each branch passage 53b of the sub-fluid passage 53 ( The fluid passage) 56 and the tip end port 56a are formed in the closing body 55C, and since other configurations are substantially the same as the configuration of the rotary nozzle 40 shown in FIG. 3, the same reference numerals are given and detailed description is omitted. To do.

Then, when the fluid S of water or cement slurry is high-pressure jetted into the ground 8 from the jet nozzles 48, 58 of the rotating body 51 to drill the ground 8, the jet holes 48a, 58a of the jet nozzles 48, 58 are formed. Air A can be injected at high pressure from the tip openings 48c and 58c around the. As a result, when the expandable body 20 is extended in the horizontal direction to drill the ground directly below the existing structure 9 in the ground 8, the tip openings around the nozzle holes 48a, 58a of the injection nozzles 48, 58 are formed. Since the air A can be jetted at high pressure from the 48c and 58c, the ground drilling can be performed easily and surely and smoothly.

FIG. 15 is an explanatory view showing a state immediately before ground improvement of the ground improvement apparatus of the second embodiment of the present invention, and FIG. 16 is an explanatory view showing a state during ground improvement of the ground improvement apparatus.

As shown in FIG. 15 and FIG. 16, the ground improvement device 70 uses a small boring machine as a base machine to extract water or cement from a rotary nozzle 40 provided on a rod (movable part) 78 for excavation (for boring). A fluid S such as a slurry (solidifying material slurry) is injected into the ground 8 at a high pressure to perform drilling and improvement of the ground 8. A base 71, an apparatus main body 72 provided on the base 71, and A swivel head 74 is attached to the apparatus main body 72 so as to be movable up and down via a movable plate 73 whose drive source is a hydraulic cylinder (not shown). The swivel head 74 includes a spindle 75 through which a rod 78 is inserted and a rod chuck 76 that is provided at the lower end of the spindle 75 and holds the rod 78. The manual lever 77 is operated to vertically move the rod 78. You can do it.

Further, the rotary nozzle 40 shown in FIG. 3 is attached to the lower end (tip) 78a of the rod 78. A fluid S such as water for excavation or cement slurry for improvement is switched and supplied to the main fluid passage 43 of the rotary nozzle 40 from a pipe 79 inserted in a cylindrical rod 78. The rotary nozzle 40 is adapted to rotate by the reaction force of the jetting force of the fluid S. The rod 78 can be made long by adding a plurality of rods.

Next, the drilling and improvement of the ground 8 using the ground improving device 70 will be described.

First, as shown in FIG. 15, a rod 78 having a lower end 78a provided with a rotary nozzle 40 that rotates by a reaction force of the jetting force of the fluid S is attached to a swivel head 74 of a ground improvement device 70, and a manual lever 77 is operated. The rod 78 is lowered vertically (vertically). At this time, the fluid S for excavation is jetted from the jet nozzles 48 and 58 of the rotary nozzle 40 into the ground 8 to loosen the ground 8 and penetrate the rod 78.

Next, as shown in FIG. 16, after the rod 78 is penetrated to a predetermined depth, the rod 78 is pulled out while injecting the improving fluid S from the injection nozzles 48 and 58 of the rotary nozzle 40 to circle the ground 8. A columnar improved body K is formed.

According to the ground improvement method using the ground improvement device 70, the fluid S for excavation is injected from the injection nozzles 48 and 58 of the rotary nozzle 40 into the ground 8 to loosen the ground 8 and penetrate the rod 78, After injecting 78 to a predetermined depth, the rod 78 is pulled out while injecting the improving fluid S from the injection nozzles 48 and 58 of the rotary nozzle 40 to form the cylindrical improved body K in the ground 8, so that the manual operation is manually performed. By the small ground improvement device 70 that moves the rod 78 up and down by operating the lever 77, the ground can be improved easily and reliably in a wide range in a short time. Further, by using the rotary nozzle 40 with the injection nozzle attached also on the outer peripheral surface side, it becomes possible to form an improved body having a larger diameter.

According to the first embodiment, the injection nozzle is attached to at least one of the three injection holes, but the injection nozzle is attached to two of the three injection holes, or all three injection holes are attached. The injection nozzle may be attached to the hole, and the combination of the injection nozzle attachments may be changed according to the application. Further, the number of injection holes formed on the same circumference of the rotating body may be two or less or four or more. Furthermore, although the magnetic sensor is used as the rotation sensor, an optical system may be used.

Further, according to the first embodiment, the expandable body attached to the lower end of the movable part of the ground improvement device is composed of a plurality of large, medium and small cylindrical bodies, but the expandable body has a plurality of square shapes such as large, medium and small. You may make it comprised with a cylinder. In addition, the movable part of the pile driver is equipped with an expandable body equipped with a rotary nozzle at its tip, but the extension mast (movable part) has a expandable body equipped with a rotary nozzle at its tip as a base machine such as a backhoe or power shovel. May be attached. Further, although the ground is improved just below the existing structure in the ground such as the common groove, the ground may be improved directly below the existing structure on the ground.

8 Ground 10 Ground Improvement Device 18 Lifting Casing (Movable Part)
20 telescopic body 26 fluid passage 31 wire 36 electric winch (winch)
40, 40A, 40B, 40C rotating nozzle 41 holder (fixed part)
41a Front surface (opposite surfaces)
42 Shaft 43 Main fluid passage (fluid passage)
43d Tip opening 44 Communication passage 48 Injection nozzle 48a Nozzle hole 48b Air passage 48c Tip opening 49 Air supply passage 51 Rotating body (rotating part)
51b Rear surface (opposite surface)
53 Secondary fluid passage (fluid passage)
53a circular passage (annular passage)
53b Branch passage 55B Blocking plug 56 Injection hole (fluid passage)
56a Tip opening 56b Base end opening 58 Injection nozzle 58a Nozzle hole 58b Air passage 58c Tip opening 59 Air supply passage 60 Rotation sensor 78 Rod (movable part)
78a Lower end (tip)
S Water or cement slurry (fluid)
A Air for assisting drilling K Improved body F Injection force F'Reaction force θ, θ'Inclination angle

Claims (7)

Used in a ground improvement device that performs high-pressure injection of a fluid from an injection nozzle into the ground to perform drilling and improvement of the ground, in a rotary nozzle that rotates by a reaction force of the injection force of the fluid,
A rotating portion is rotatably provided around a shaft portion of a fixed portion in which a fluid passage through which the fluid flows is formed, in which a fluid passage communicating with the fluid passage is formed,
Is inclined portion of the tip in an oblique direction of the front Symbol fixing portion fluid passage of the rotating part to the outside of the vertical plane against the fluid passage around the shaft portion of the formed toward the outer circumferential side,
The portion of the tip of the inclined fluid passage provided tip opening, Installing an injection nozzle to the tip opening,
Further, a tip port is formed at the tip of the shaft part of the fluid passage of the fixed part, an injection nozzle is attached to this tip port, and the tip is attached to the tip port of the tip of the fluid passage inclined about the injection nozzle. rotary nozzle, characterized in that the reaction force of the jet force of the fluid injected from the injection nozzle and the freely rotating the rotary unit about said shaft portion. The rotary nozzle according to claim 1, wherein
A holder as the fixing portion, wherein a main fluid passage through which the fluid flows is formed up to a shaft portion protruding in the center,
A sub-fluid passage communicating with the main fluid passage is formed, and a rotating body as the rotating portion that rotates about the shaft portion of the holder is provided,
Wherein the rotating body, a plurality of radially formed toward the outer circumferential side from the sub fluid passage by a predetermined angle inclined obliquely injection holes communicating with the auxiliary fluid passage in a vertical plane outside against the main fluid passage,
Rotary nozzle, characterized in that the Install the embolization at the tip opening of the other injection hole is attached to at least one injection nozzle tip port of the plurality of injection holes. The rotary nozzle according to claim 2, wherein
The sub-fluid passage of the rotating body is formed by an annular passage that communicates with the main fluid passage of the holder by a plurality of communication passages, and a plurality of branch passages radially formed from the annular passage toward the outer peripheral side. A rotary nozzle, wherein a base end of the injection hole is connected to a branch passage. The rotary nozzle according to claim 2, wherein
Rotary nozzle, characterized in that formed at different angles inclined obliquely to a vertical plane outside against the main fluid path of the plurality of injection holes. The rotary nozzle according to claim 2, wherein
A rotary nozzle characterized in that a plurality of the plurality of injection holes are formed at a predetermined distance from the center of the rotating body toward the outer peripheral side. The rotary nozzle according to claim 2, wherein
A rotary nozzle, wherein a rotation sensor for detecting a rotation state of the rotating body is provided on opposite surface sides of the holder and the rotating body. The rotary nozzle according to claim 2, wherein
A tip end of an air passage for supplying air for assisting drilling to each of the injection nozzles attached to the tip of the main fluid passage and the tip of the injection hole is provided in parallel with the nozzle hole of each of the injection nozzles. A rotary nozzle characterized in that an air passage is communicated with each air supply passage formed in the holder and the rotating body.

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