JP2023072747A - Excavation and agitation device and deep mixing method - Google Patents

Abstract

To provide an excavation and agitation device which can diffuse a slurry to the whole of a column that is finally constructed and can effectively prevent a corotation phenomenon, and thereby can construct a column of high quality without variation in strength.SOLUTION: An excavation and agitation device includes: a cylindrical rotation shaft 10 where a slurry discharge hole is formed at the tip; an excavation blade 20 which is fixed to the tip of the rotation shaft 10 and is mounted with an excavation claw for excavating the ground; an agitation blade 30 which is fixed to a part other than the tip of the rotation shaft 10, and agitates the ground; a corotation prevention blade 40 which is fixed to a boss 41 rotatably mounted on the outside of a part other than the tip of the rotation shaft 10 and prevents rotation of the rotation shaft 10 from being transmitted by the boss 41; and a nozzle 60 which is mounted on the slurry discharge hole of the rotation shaft 10, has a flow channel of the slurry having a smaller diameter toward an outlet from an inlet provided therein, accelerates a flow of the slurry and jets the slurry into the ground.SELECTED DRAWING: Figure 1

Description

Application for Article 30, Paragraph 2 of the Patent Act has been filed (1) February 17, 2021 Published a publication titled "DG Column Construction Method - Slurry System Mechanical Stirring Deep Mixing Method - Quality and Construction Management Guidelines" (2) ) March 6, 2021 Published a publication titled "DG Column Method - Slurry Mechanical Stirring Deep Mixing Method - GBRC Performance Certification (No. 22-20)" (3) April 14, 2021 Website https://www. gbrc. or. jp/https://www. gbrc. or. jp/building_confirm/ https://www. gbrc. or. jp/building_confirm/gijyutu_ninsho/ https://www. gbrc. or. jp/search/gijyutu. php? go_search=true&display_order=agent&display_sort=desc&page=publish on 9

(4) July 30, 2021 "NEW TECHNOLOGY TO SUPPORT PEACE OF MIND DG Column construction method Slurry-based mechanical stirring type deep mixing processing construction method Construction technology performance certification / GBRC performance certification No. 20-22” (5) May 24, 2021 Website https://www. daiwalantec. jp/index. html https://www. daiwalantec. Published at jp/reinforcement/ (6) August 16, 2021 Website https://www. gbrc. or. jp/https://www. gbrc. or. jp/building_confirm/ https://www. gbrc. or. jp/building_confirm/gijyutu_ninsho/ https://www. gbrc. or. jp/search/gijyutu. php? go_search=true&display_order=agent&display_sort=desc&page=publish on 9

Application for application of Article 30, Paragraph 2 of the Patent Act has been filed (7) August 27, 2021 Publication titled “DG Hybrid Construction Method Explanatory Materials” (8) August 16, 2021 DG Hybrid Construction Method Performance Certification (9) October 25, 2021 “NEW TECHNOLOGY TO SUPPORT PEACE OF MIND DG Hybrid Method Checked Steel Plate Steelmaking” Pile-shaped ground reinforcement method construction technology performance certification / GBRC performance certification No. 21-06 using a soil improvement body with pipes” published

The present invention is the excavation for constructing a column in the ground by mechanically mixing and agitating the slurry and the soil while injecting the slurry (cement milk) in which the cement-based solidifying material is mixed with water into the ground. It relates to a stirring device and a deep mixing processing method.

Conventionally, a deep mixing method using an excavator and agitator has been practiced. The deep mixing method is a method for improving the ground of structures such as buildings, structures, and retaining walls. By mechanically mixing and stirring, a column (columnar improvement body) is constructed in the ground. Columns reinforce the ground and support the structure. In the present specification, the term "cement-based solidifying material" refers to a solidifying material and cement whose main component is cement for the purpose of solidifying soil, and is sometimes called a "solidifying material" in general. Further, the term "slurry" as used herein refers to a liquid obtained by mixing a cement-based solidifying material with water, and is generally called "cement milk".

For example, as disclosed in JP-A-2019-214911 (Patent Document 1), JP-A-2017-048616 (Patent Document 2), and Utility Model Registration No. 3215453 (Patent Document 3), conventional The excavating agitator has a configuration in which an excavating blade, a stirring blade and a co-rotation preventing blade are provided on a cylindrical rotary shaft. A conduit for supplying slurry is formed inside the cylindrical rotating shaft, and the slurry is discharged into the ground from a slurry discharge hole formed at the tip of the rotating shaft. The ground is excavated by the excavating blades, and the excavated soil and the slurry are mixed and stirred by the stirring blades. Further, when the excavation agitator excavates and mixes and agitates the ground, the anti-corotation blades abut against the wall surface of the excavation hole and maintain a stopped state. The co-rotation prevention blades in the stopped state prevent the co-rotation phenomenon of the soil and the slurry to be mixed and agitated.

JP 2019-214911 A JP 2017-048616 A Utility Model Registration No. 3215453

In the conventional excavating agitator described above, when the ground is excavated and mixed and agitated, the slurry is discharged into the ground only by the pressure of the force pump. For this reason, the slurry is not spread over the entire column that is finally constructed, and the column is mixed with unsolidified lumps of soil, resulting in variations in the strength of the column.

Further, although the conventional excavator and agitator was provided with co-rotation prevention blades, it was not possible to remove the soil clumps adhering to the agitator blades. That is, as the ground is excavated and mixed and agitated by the excavator and agitator, the soil adheres to the agitating blades over time and becomes a lump, causing a co-rotation phenomenon in which the agitating blade and the lump of soil rotate together. Due to this co-rotating phenomenon, the mixing and stirring of the slurry and the soil by the stirring blades becomes insufficient, and the strength of the finally constructed column becomes insufficient.

Furthermore, in the conventional excavator agitator, the problem of insufficient diffusion of the slurry and the co-rotation phenomenon sometimes occur simultaneously, and it is always difficult to construct a column with a predetermined quality.

The present invention has been made in view of the above problems, and is capable of diffusing slurry throughout the column that is finally constructed and effectively preventing the co-rotation phenomenon. It is an object of the present invention to provide an excavation stirrer and a deep mixing treatment method capable of constructing a high-quality column with uniform strength.

(1) In order to achieve the above objects, the excavation agitator of the present invention mechanically mixes and agitates the slurry and the soil while injecting the slurry obtained by mixing the cement-based solidifying material with water into the ground. is an excavator and agitator for constructing a column in the ground, which has therein a conducting path for supplying the slurry into the ground, and a slurry discharge hole communicating with the conducting path is provided at the tip portion. a cylindrical rotating shaft formed in a pillar, an excavating wing fixed to the tip of the rotating shaft and having an excavating claw for digging the ground, and a portion other than the tip of the rotating shaft , a stirring blade for stirring the ground, and a co-rotation prevention blade fixed to a boss rotatably attached to the outside of the portion other than the tip of the rotating shaft, and preventing the rotation of the rotating shaft from being transmitted by the boss. and a nozzle that is attached to the slurry discharge hole of the rotary shaft, has therein a flow path for the slurry that decreases in diameter from the inlet to the outlet, and accelerates the flow of the slurry to be sprayed into the ground. , provided.

(2) Preferably, in the excavator and agitator of (1) above, two or more of the slurry discharge holes are formed at the tip of the rotary shaft, and the nozzles are provided in each of the two or more slurry discharge holes. It is attached.

(3) Preferably, in the excavator and agitator of (1) or (2), the diameter of the outlet of the nozzle is 5 mm to 25 mm, and the nozzle is detachably attached to the slurry discharge hole.

(4) Preferably, in the excavating agitator according to any one of the above (1) to (3), when the rotating shaft is rotated in one direction, the soil of the ground is prevented from covering the nozzle. A nozzle cover is provided at the tip of the rotary shaft.

(5) Preferably, in the excavation stirrer according to any one of the above (1) to (4), three or four sets of the stirring blades, each set consisting of two blades, are provided, and each set of the stirring blades is connected to the rotating It is fixed in symmetrical positions on different parts other than the tip of the shaft.

(6) Preferably, in the excavating agitator according to any one of the above (1) to (5), a vertically extending earth removal plate is fixed to the boss to which the anti-corotation blade is fixed.

(7) Preferably, in the excavator and agitator of (6) above, the co-rotation prevention blades are substantially U-shaped or approximately U-shaped, and two or three ends of the co-rotation prevention blades are fixed. and the blade plate is fixed to at least one of the bosses.

(8) In order to achieve the above object, the deep mixing method of the present invention uses the excavation agitator according to any one of the above (1) to (7) to prepare slurry in which a cement-based solidification material is mixed with water. is injected into the ground, and the slurry and soil are mechanically mixed and stirred to build a column in the ground, wherein the excavation stirrer is rotated in one direction, The ground is excavated from the position where the head of the column is formed to the position where the tip of the column is formed by propelling the slurry through the ground while spraying the slurry from the nozzle. and a step of mixing and stirring the slurry and the soil, and stopping the spraying of the slurry from the nozzle and moving the excavation stirrer to a position where the tip of the column is formed until a predetermined time elapses. After the predetermined time has passed, the step of retreating by approximately the height of the excavation agitator while rotating the excavation agitator in the opposite direction, and rotating the excavation agitation device in one direction while advancing to a position where the tip of the column is formed, and a step of retreating to the position where the head of the column is formed while rotating the excavator and agitator in the opposite direction.

(9) In order to achieve the above object, the deep mixing method of the present invention uses the excavation stirring device according to any one of the above (1) to (7) to create a slurry in which a cement-based solidification material is mixed with water. is injected into the ground, and the slurry and soil are mechanically mixed and stirred to build a column in the ground, wherein the excavation stirrer is rotated in one direction excavating the ground to an arbitrary position between the position where the head of the column is formed and the position where the tip of the column is formed by advancing the ground through the ground; While rotating the excavation agitator in one direction and spraying the slurry from the nozzle, it is advanced through the ground, from the arbitrary position to the position where the tip of the column is formed. a step of excavating the ground and mixing and stirring the slurry and the soil; holding the formed position, after the predetermined time has elapsed, retracting the excavation agitator by approximately the height of the excavation agitator while rotating it in the opposite direction; Rotating in one direction, the step of advancing to the position where the tip of the column is formed; and rotating the excavator and stirring device in the opposite direction, retreating the device to the position where the head of the column is formed. , from the position where the head of the column is formed to the arbitrary position by rotating the excavation stirring device in one direction and advancing in the ground while spraying the slurry from the nozzle; a step of mixing and agitating the slurry and the soil; stopping injection of the slurry from the nozzle and rotating the excavation agitating device in the opposite direction from the arbitrary position to the position where the head of the column is formed; and a step of retracting.

(10) Preferably, in the deep mixing method of (8) or (9), the slurry and soil are mixed from the position where the head of the column is formed to the position where the tip of the column is formed. are mixed and agitated, and the excavator agitator is pulled up from the ground, and then a checkered steel pipe is inserted into the mixed and agitated slurry and soil, thereby forming the column integrated with the checkered steel pipe as described above. Build in the ground.

In the excavation stirrer and the deep mixing method of the present invention, the slurry is sprayed into the ground at a pressure higher than usual from the nozzle attached to the slurry discharge hole. This allows the slurry to spread throughout the final built column. In addition, the clump of soil adhering to the agitating blade can be removed by the earth removal plate fixed to the boss of the co-rotation prevention blade, and the co-rotation phenomenon can be effectively prevented. These synergistic effects make it possible to construct high-quality columns with uniform strength.

BRIEF DESCRIPTION OF THE DRAWINGS It is a front view which shows the excavation stirrer based on 1st Embodiment of this invention. It is a right view which shows the excavation stirrer based on said 1st Embodiment. FIG. 3(a) is an enlarged view of the tip of the excavator and stirrer of FIG. FIG. 3(b) is a sectional view taken along line AA of FIG. 3(a). FIG. 3(c) is a front view showing a nozzle provided at the tip of the excavator agitating device. FIG. 3(d) is a right side view showing the nozzle. FIG. 3(e) is a sectional view showing the nozzle. It is a front view which shows the excavation stirrer based on 2nd Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows the deep mixing processing construction method which concerns on 1st Embodiment of this invention. It is the schematic which shows the first half of the deep mixing processing construction method which concerns on 2nd Embodiment of this invention. It is the schematic which shows the latter half of the deep-layer mixing processing construction method which concerns on said 2nd Embodiment. It is a schematic diagram showing a deep mixing processing method according to a third embodiment of the present invention. It is a schematic diagram showing the main part of the modification of the excavation stirrer of the present invention.

1. 1. Drilling Stirrer According to First Embodiment A drilling stirrer according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG.

As shown in FIGS. 1 and 2 , the excavation stirring device 1 is mainly composed of a rotating shaft 10 , an excavating blade 20 , a stirring blade 30 , a co-rotation prevention blade 40 and an earth removal plate 50 .

1.1 Rotating Shaft As shown in FIGS. 1, 2 and 3(b), the rotating shaft 10 is a cylindrical member and has a conduction path 10a inside. A slurry 100 (see FIGS. 5 to 7) in which a cement-based solidifying material is mixed with water is supplied to the conduit 10a. A grout pump (not shown) is used to supply the slurry 100 . For example, the rotating shaft 10 has a diameter of 139 mm and a total length of 883 mm.

Two slurry discharge holes 10b are formed at the tip of the rotary shaft 10 and communicate with the conduit 10a. The two slurry discharge holes 10b are arranged at symmetrical positions at the tip of the rotary shaft 10. As shown in FIG. The slurry discharge hole 10b is circular, and a female screw portion is formed on the inner peripheral surface. For example, the inner diameter of the slurry discharge hole 10b is 36 mm. Nozzles 60, which will be described later, are replaceably attached to the two slurry discharge holes 10b by screws.

Here, the excavation stirring device 1 of the present embodiment selects either two or one as the number of slurry discharge holes 10b for discharging the slurry 100 according to the discharge amount of the slurry necessary for soil improvement. is possible. When using two slurry ejection holes 10b, a nozzle 60 is attached to each of the two slurry ejection holes 10b. On the other hand, when one slurry ejection hole 10b is used, a nozzle 60 is attached to one slurry ejection hole 10b, and a bolt (not shown) is screwed to the other slurry ejection hole 10b to open the other slurry ejection hole 10b. to close.

A joint 11 shown in FIGS. 1 and 2 is fixed to the rear end of the rotating shaft 10 . A conduction path (not shown) is formed inside the joint 11 , and the slurry 100 is supplied to the conduction path 10 a of the rotating shaft 10 from this conduction path. The rotary shaft 10 is connected via a joint 11 to a rod 80 (see FIGS. 5 to 7) of a construction machine (not shown). For example, the maximum diameter of the rod 80 is substantially the same as that of the rotating shaft 10, and the total length is 3-6 m.

1.2 Excavation Blades As shown in FIG. 2 , the excavation stirrer 1 includes two excavation blades 20 . The two digging blades 20 are fixed at symmetrical positions on the tip of the rotating shaft 10 . Two first digging claws 21 are attached to the inner side of each digging blade 20 in the longitudinal direction. In addition, one cutting claw 23 is attached to the outer side of each digging blade 20 in the longitudinal direction. Furthermore, two second digging claws 22 are vertically fixed to the tip surface of the rotating shaft 10 . For example, the total length of one digging blade 20 is 330 mm. The total diameter of the two digging blades 20 and the diameter of the rotating shaft 10 forms a digging hole with a diameter of about 800 mm in the ground.

1.3 Stirrer Blades As shown in FIGS. 2 and 3 , the excavator stirrer 1 includes three sets of two stirrer blades 30 , for a total of six stirrer blades 30 . The six stirring blades 30 are all fixed to the rear end side of the rotary shaft 10 relative to the excavating blades 20 . A set of two stirring blades 30 are arranged at mutually symmetrical positions on the rotating shaft 10 . Of the three sets of stirring blades 30 arranged at the upper, middle and lower positions of the rotating shaft 10, the middle set of stirring blades 30 is shifted by 90° with respect to the upper and lower two sets of stirring blades 30. are placed. A set of stirring blades 30 arranged on the rotating shaft 10 is attached with one lifting claw 31, respectively. The lifting claws 31 are arranged outside the stirring blades 30 in the longitudinal direction. For example, the total length of one stirring impeller 30 is 330 mm, which is the same as that of the excavating impeller 20 .

1.4 Co-rotation Prevention Wings As shown in FIG. 1 , the excavator 1 includes a set of two co-rotation prevention wings (free wings) 40 . A single anti-rotation wing 40 has a substantially U-shape in which two horizontal portions are connected to one vertical portion. The ends of the two horizontal portions of the anti-co-rotation wing 40 are fixed to two bosses 41 respectively. Each of the two bosses 41 is rotatably attached to two collars 42 mounted on the outside of the rotating shaft 10 . The boss 41 is configured to be freely rotatable while contacting the outer peripheral surface of the collar 42 . As a result, the rotation of the rotary shaft 10 and the collar 42 is not transmitted to the co-rotation prevention wings 40 . By forming the collar 42 from a wear-resistant steel plate, wear due to contact with the anti-co-rotation blade 40 is reduced.

A single co-rotation prevention wing 40 is composed of two horizontal parts extending in the horizontal direction, upper and lower parts, and one vertical part continuous with these two horizontal parts. For example, for one anti-rotation impeller 40 , the horizontal projection length from the rotating shaft 10 to the vertical portion is 430 mm, which exceeds the total length of the excavation impeller 20 and the stirring impeller 30 . The vertical portion of the anti-corotation blade 40 contacts the wall surface of the excavation hole when the excavation agitation device 1 excavates and mixes and agitates the ground. As a result, the co-rotation prevention blade 40 is kept in a stopped state. When the soil and slurry 100 mixed and stirred by the stirring blade 30 come into contact with the horizontal portion of the co-rotation prevention blade 40 in the stopped state, co-rotation of the soil and the slurry 100 is prevented.

1.5 Unloading Plate As shown in FIG. The two blades 50 are fixed respectively to the two bosses 41 to which the co-rotation prevention wings 40 are attached. The earth removal plate 50 has a plate surface extending in the vertical direction, and the plate surface can be brought into contact with the earth lump adhering to the stirring blade 30 to remove it.

1.6 Nozzle As shown in FIGS. 3(a) and 3(b), nozzles 60 are replaceably attached to two slurry discharge holes 10b provided at the tip of the rotating shaft 10, respectively. The present invention is based on the conventional mechanical stirring type deep mixing processing method using the slurry 100 of the cement-based solidifying material, and the nozzle 60 attached to the slurry discharge port 10b applies a higher pressure than usual. It is characterized in that the slurry 100 is jetted. Injecting the slurry 100 from the nozzle 60 promotes mixing and agitation of the soil and the slurry 100 so that the slurry 100 is sufficiently spread throughout the finally constructed column. As a result, it is possible to construct high-quality columns with little variation in strength.

As shown in FIGS. 3(c) to 3(e), the nozzle 60 in this embodiment includes a hexagonal head portion 61, a male thread portion 62 for screwing into the female thread portion of the slurry discharge port 10b, and the slurry 100. and a tapered flow path 63 that accelerates the flow of Outlet 63b of nozzle 60 has a smaller diameter than inlet 63a.

The diameter of the outlet 63b of the nozzle 60 is determined by the number of nozzles 60 used and the discharge amount of the slurry 100 per unit time, and is, for example, within the range of 5 mm to 25 mm. Table 1 below shows specific examples of the diameter of the outlet 63b of the nozzle 60, the number of nozzles 60, and the diameter of the excavating agitating blade when discharging 50 to 500 liters of slurry 100 per minute. The diameter of the excavating impeller is the sum of the total length of one set of excavating impellers 20 or agitating impellers 30 and the diameter of the rotating shaft 10 . For example, the diameter of the excavating stirring blade in this embodiment is 330 mm+330 mm+139 mm≈800 mm.

As shown in FIGS. 3A and 3B, nozzle covers 70 corresponding to the two nozzles 60 are provided at the tip of the rotating shaft 10 . The nozzle cover 70 is a semicircular wall having a diameter that covers the nozzle 60, and is arranged in the forward rotation direction of the rotating shaft 10 shown in FIG. 3(b). To prevent soil from covering a nozzle 60 when ground is excavated and mixed and agitated by forward rotation of a rotating shaft 10.例文帳に追加Such a nozzle cover 70 prevents the nozzle 60 from being damaged and soil from flowing back into the rotating shaft 10, thereby maintaining smooth injection of the slurry 100. FIG.

2. The excavation stirring device of the second embodiment The excavation stirring device 1 of the first embodiment described above has a configuration in which three sets of six stirring blades 30 are provided on the rotating shaft 10, but the number of stirring blades 30 is six. It is not limited to one sheet. As in the excavation stirring device 2 of the second embodiment shown in FIG. In this case, it is preferable that the co-rotation prevention wing 40 has a substantially Y-shape in which three horizontal portions are connected to one vertical portion. Such a substantially Y-shaped anti-corotation wing 40 is fixed to three bosses 41 . Each of the three bosses 41 is rotatably attached to three collars 42 mounted at upper, middle and lower positions of the rotating shaft 10 . A removal plate 50 is fixed to each of the three bosses 41 . The intermediate blade 50 is positioned 180° opposite to the upper and lower blades 50 and is not shown in FIG.

3. Deep Mixing Processing Method of First Embodiment A deep mixing processing method of the first embodiment of the present invention will be described with reference to FIG. 5 .

As shown in FIG. 5, the deep mixing treatment method of the first embodiment uses the excavation stirring device 1 of the first embodiment described above to inject the slurry 100 into the ground while mixing the slurry 100 and the soil. A column is constructed in the ground by mechanically mixing and stirring. In the deep layer mixing method of the first embodiment, one column is built in the ground by reciprocating the excavator 1 once (one cycle).

Symbols “A” to “F” in FIG. 5 indicate a plurality of steps included in the deep mixing treatment method of the first embodiment. The excavation stirrer 1 is connected to a rod 80 of a construction machine (not shown), and advances or retreats through the ground while rotating forward or backward. "Forward rotation" means the clockwise direction shown in FIG. 3(b), and "reverse rotation" means the counterclockwise direction shown in FIG. 3(b). In the deep layer mixing method of the first embodiment, various construction machines such as crawler three-point support machines, backhoes, small crawler types, rough terrain crane types, and pole erection vehicles are used, depending on the site and construction conditions. Is possible. The excavation agitator 1 of the first embodiment is merely an example, and the excavation agitator 2 of the second embodiment may be used.

3.1 Excavation, Mixing and Stirring, and Slurry Discharge First, as shown in A to C in FIG. By excavating the ground from the position where the head of the column is formed to the position where the tip of the column is formed, the soil and the slurry 100 are mixed and stirred.

3.2 Column Tip Treatment Next, as shown in C and D in FIG. is formed. Next, as shown by E in FIG. 5, after a predetermined time has passed, the excavation agitator 1 is reversed and retreated by approximately the height of the excavation agitation device 1 . Next, as indicated by F in FIG. 5, while rotating the excavator agitating device 1 forward, it is advanced to a position where the tip of the column is formed. Through the above steps, the soil at the tip of the column and the slurry 100 are sufficiently stirred and mixed.

3.3 Pulling Up and Stirring the Excavation Stirrer After that, as indicated by F, G, and H in FIG. The drilling stirrer 1 is retracted from the position where the head of the column is formed. The deep mixing processing method of the first embodiment is completed by the above steps.

4. Deep Mixing Processing Method of Second Embodiment A deep mixing processing method of a second embodiment of the present invention will be described with reference to FIGS. 6 and 7. FIG.

As shown in FIGS. 6 and 7, the deep mixing method of the second embodiment divides the position from the position where the tip of the column is formed to the position where the head of the column is formed into an upper section and a lower section. Then, one column is constructed in the ground by constructing the lower section of the column first and constructing the upper section of the column later.

The deep mixing method of the second embodiment described below is effective when the total length of the column (improvement length of the ground) is long and it is difficult to pull up the excavation stirring device 1 . Also, the soil and slurry 100 of the lower column section applied earlier receives the weight of the soil of the upper section applied later. As a result, it is possible to prevent the soil and slurry 100 in the previously constructed column lower section from overflowing into the later constructed column upper section.

Symbols "A" to "N" in FIGS. 6 and 7 indicate a plurality of steps included in the deep mixing method of the second embodiment. As in the deep mixing method of the first embodiment described above, the excavation stirrer 1 is connected to a rod 80 of a construction machine (not shown) and advances or retreats through the ground while rotating forward or reverse. The deep layer mixing method of the second embodiment can also use various construction machines depending on the site and construction conditions. The excavation agitator 1 of the first embodiment is merely an example, and the excavation agitator 2 of the second embodiment may be used.

4.1 Construction of Column Lower Section First, as shown in A and B in FIG. Excavate the ground to approximately halfway to the position where the In other words, the ground is dry-drilled without discharging the slurry 100 from the head of the column to the intermediate position.

Next, as shown in C and D in FIG. 6, while the excavation stirring device 1 is rotated forward and the slurry 100 is jetted from the nozzle 60, it is advanced through the ground, thereby moving from the middle position to the tip of the column. The ground is excavated up to the position where the part is formed, and the soil and the slurry 100 are mixed and stirred.

Next, as indicated by D and E in FIG. 6, the injection of the slurry from the nozzle 60 is stopped, and the excavation stirrer 1 is held at the position where the tip of the column is formed until a predetermined time elapses. . Next, as shown by F in FIG. 6, after a predetermined time has passed, the excavation agitator 1 is reversed and retreated by approximately the height of the excavation agitation device 1 . Next, as indicated by G in FIG. 6, while rotating the excavator agitator 1 forward, it is advanced to a position where the tip of the column is formed. Through the above steps, the soil at the tip of the column and the slurry 100 are sufficiently stirred and mixed.

After that, as indicated by G and H in FIG. 6, the excavator agitator 1 is rotated in the opposite direction and retreated to the position where the head of the column is formed. By the above steps, the construction of the column lower section in the deep mixing method of the second embodiment is completed.

4.2 Construction of Column Upper Section Next, as indicated by I, J, and K in FIG. The soil and the slurry 100 are mixed and stirred from the position where the head of the column is formed to the intermediate position.

Next, the injection of the slurry from the nozzle is stopped, and as indicated by L in FIG. After that, as indicated by M and N in FIG. 7, the excavator agitator 1 is rotated in the opposite direction and retracted from the middle position of the column to the position where the head is formed. The above steps complete the construction of the column upper section. This completes the deep mixing method of the second embodiment, and one column is constructed in the ground.

5. Deep Mixing Processing Method of Third Embodiment A deep mixing processing method of the third embodiment of the present invention will be described with reference to FIG.

The checkered steel pipe 90 shown in FIG. 8 may be integrated with the column formed in the ground by the deep mixing method of the first and second embodiments described above. That is, as indicated by H in FIG. 5 and N in FIG. 7, the slurry 100 and the soil are mixed and stirred from the position where the head of the column is formed to the position where the tip of the column is formed, After pulling up the excavating agitator 1 from the ground, the checkered steel pipe 90 is inserted into the mixed and agitated slurry 100 and soil. As a result, a composite column in which the checkered steel pipes 90 are integrated can be constructed in the ground.

As shown in FIG. 8, the total length of the checkered steel pipe 90 is preferably the length obtained by subtracting the column diameter D from the total length L of the column. In this case, the checkered steel pipe 90 has a length that does not reach the tip improved portion of the column having the same height as the column diameter D. The total length of the checkered steel pipe 90 may be the same as the total length L of the column. That is, the total length of the checkered steel pipe 90 is preferably the length obtained by subtracting a value of 0 or more and D or less from the total column length L.

According to the deep mixing treatment method of the third embodiment shown in FIG. 8, the checkered steel pipe 90 having a large number of irregularities on the surface has a large adhesive force with the central portion of the column. By embedding and integrating such a checkered steel pipe 90 in the column, the durability of the column can be increased, and the bearing capacity of the ground can be effectively exhibited.

6. Effect In the excavation agitator 1 and 2 of the present embodiment described above and the deep mixing treatment method using these, slurry is injected into the ground at a pressure higher than usual by the nozzle 60 attached to the slurry discharge hole 10b. be. This allows the slurry 100 to spread throughout the column that will eventually be built. Also, the soil removal plate 50 fixed to the boss 41 of the co-rotation prevention blade 40 can remove the lump of soil adhering to the stirring blade 30, thereby effectively preventing the co-rotation phenomenon. These synergistic effects make it possible to construct high-quality columns with uniform strength.

Furthermore, when a column integrated with the checkered steel pipe 90 is built in the ground, the checkered steel pipe 90, which has a large adhesive force, is embedded in the column and integrated into the column, thereby increasing the resistance of the column and increasing the strength of the ground. It is possible to effectively demonstrate the bearing capacity of

7. Others The excavation agitator of the present invention and the deep mixing treatment method using these are not limited to the configuration and process of each embodiment described above. For example, the following changes are possible.

The outer shape of the nozzle 60 shown in FIGS. 3(c) and 3(d) is not limited to a hexagon. The outer shape of the nozzle 60 can be various shapes such as, for example, triangular, square, and circular. Also, the number of nozzles 60 is not limited to two, and the number of nozzles 60 may not be exchangeably attached to the rotating shaft 10 . For example, the number of nozzles 60 may be one or three or more. When the diameter of the excavating stirring blade is as small as 300 to 600 mm, one nozzle 60 may be welded to one discharge hole 10b of the rotating shaft 10 as shown in FIG. Furthermore, the external shape of the nozzle cover 70 shown in FIGS. 3(a) and 3(b) is not limited to a semicircular shape. As shown in FIG. 9, the outer shape of the nozzle cover 70 may be, for example, a circle that covers the nozzle 60 from 360°.

In FIG. 2, the two second digging claws 22 provided at the tip of the rotary shaft 10 may be, for example, one fishtail type as shown in FIG. Further, the excavating blade 20 shown in FIG. 2 has a configuration in which a small first excavating claw 21 and a large cutting claw 23 are provided. This is because the outer claws of the excavating blade 20 are worn more severely, so the outer claws are made large cutting claws 23 . However, as shown in FIG. 9, all the claws provided on the excavating blade 20 may be the first digging claws 21 of the same size. Furthermore, when the diameter of the excavating stirring blade is as small as 300 to 600 mm, the lifting claw 31 shown in FIG. 2 may be omitted.

In the deep mixing processing method of the second embodiment, the slurry discharge start position at B in FIG. 6 is set at an approximately intermediate position from the head of the column to the position where the tip is formed. However, the slurry discharge start position is not limited to the intermediate position, and can be any position between the position where the head of the column is formed and the position where the tip of the column is formed. .

Reference Signs List 1, 2 excavation stirrer 10 rotary shaft 10a conduit 10b slurry discharge hole 11 joint 20 excavation blade 21 first digging claw 22 second digging claw 23 cutting claw 30 stirring blade 31 lifting claw 40 co-rotation prevention blade (free blade)
41 boss 42 collar 50 blade plate 60 nozzle 61 head 62 male screw part 63 channel 63a inlet 63b outlet 70 nozzle cover 80 rod 90 checkered steel pipe 100 slurry

Claims (10)

An excavating agitator for constructing a column in the ground by mechanically mixing and agitating the slurry and the soil while injecting the slurry obtained by mixing the cement-based solidifying material with water into the ground,
a cylindrical rotating shaft having therein a conducting path for supplying the slurry into the ground, and having a slurry discharge hole formed at the tip end portion communicating with the conducting path;
an excavating wing fixed to the tip of the rotating shaft and having an excavating claw for excavating the ground;
a stirring blade fixed to a portion other than the tip of the rotating shaft for stirring the ground;
a co-rotation prevention wing fixed to a boss rotatably attached to the outside of the portion other than the tip of the rotating shaft, and preventing rotation of the rotating shaft from being transmitted by the boss;
a nozzle attached to the slurry discharge hole of the rotating shaft, provided therein with a flow path for the slurry, the diameter of which decreases from the inlet to the outlet, and for accelerating the flow of the slurry and injecting it into the ground;
A drilling agitator characterized by comprising: 2. The excavating agitator according to claim 1, wherein two or more of said slurry discharge holes are formed at the tip of said rotating shaft, and said nozzles are attached to each of said two or more of said slurry discharge holes. 3. The excavating agitator according to claim 1, wherein the nozzle has an outlet diameter of 5 mm to 25 mm, and the nozzle is detachably attached to the slurry discharge hole. 4. Any one of claims 1 to 3, wherein a nozzle cover for preventing the soil of the ground from covering the nozzle when the rotating shaft is rotated in one direction is provided at the tip of the rotating shaft. A drilling agitator according to any one of the preceding paragraphs. 3 sets or 4 sets of said stirring blades, each set consisting of two blades, are provided, and each set of said stirring blades is fixed at a symmetrical position in a different part other than the tip of said rotating shaft. A drilling agitator according to any one of the preceding claims. The excavation agitator according to any one of claims 1 to 5, wherein a vertically extending earth removal plate is fixed to the boss to which the co-rotation prevention blade is fixed. The co-rotation prevention wing is substantially U-shaped or substantially U-shaped, and has two or three bosses for respectively fixing two or three ends of the co-rotation prevention wing, and at least one boss 7. The excavation agitator according to claim 6, wherein the blade is fixed to the. Using the excavation blade agitating device according to any one of claims 1 to 7, the slurry and soil are mechanically mixed while injecting the slurry obtained by mixing the cement-based solidification material with water into the ground. A deep mixing method for building a column in the ground by stirring,
The tip of the column is formed from the position where the head of the column is formed by rotating the excavating agitator in one direction and advancing it through the ground while spraying the slurry from the nozzle. a step of excavating the ground to a position where the slurry and soil are mixed and stirred;
a step of stopping injection of the slurry from the nozzle and holding the excavator and agitator at a position where the tip of the column is formed until a predetermined time elapses;
After the predetermined time has elapsed, a step of retreating by approximately the height of the excavation agitator while rotating the excavation agitation device in the opposite direction;
a step of rotating the excavation agitator in one direction and advancing it to a position where the tip of the column is formed;
a step of retracting the excavation agitator to a position where the head of the column is formed while rotating in the opposite direction;
A deep mixing treatment method comprising: Using the excavation blade agitating device according to any one of claims 1 to 7, the slurry and soil are mechanically mixed while injecting the slurry obtained by mixing the cement-based solidification material with water into the ground. A deep mixing method for building a column in the ground by stirring,
By advancing through the ground while rotating the excavation stirring device in one direction, it reaches an arbitrary position between the position where the head of the column is formed and the position where the tip of the column is formed. excavating the ground to
While rotating the excavation stirring device in one direction and spraying the slurry from the nozzle, it is advanced through the ground from the arbitrary position to the position where the tip of the column is formed. excavating the ground of and mixing and stirring the slurry and soil;
a step of stopping injection of the slurry from the nozzle and holding the excavator and agitator at a position where the tip of the column is formed until a predetermined time elapses;
After the predetermined time has elapsed, a step of retreating by approximately the height of the excavation agitator while rotating the excavation agitation device in the opposite direction;
a step of rotating the excavation agitator in one direction and advancing it to a position where the tip of the column is formed;
a step of retracting the excavation agitator to a position where the head of the column is formed while rotating in the opposite direction;
By rotating the excavation agitator in one direction and advancing it through the ground while spraying the slurry from the nozzle, the above-mentioned A step of mixing and stirring the slurry and the soil;
a step of stopping the jetting of the slurry from the nozzle and retracting the excavator and agitator from the arbitrary position to a position where the head of the column is formed while rotating in the opposite direction;
A deep mixing treatment method comprising: The slurry and soil are mixed and agitated from the position where the column head is formed to the position where the column tip is formed, and the excavator and agitator are pulled up from the ground and mixed and agitated. 10. The deep mixing treatment method according to claim 8 or 9, wherein the column integrated with the checkered steel pipe is constructed in the ground by inserting the checkered steel pipe into the slurry and the soil.

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