JPH08134889A - Soil improvement method - Google Patents

Abstract

PURPOSE: To improve the working circumstances on the ground in sequential and continuous processes in which a soil improving device is inserted and drawn out and miniaturize a drive device rotating a plurality of rotary shafts and continuously improve the ground of a large diameter part. CONSTITUTION: Small diameter preparatory holes are cut by excavation of the ground without injection of a solidifying material 2 on inserting a plurality of rotary shafts 1 into the ground and the excavated soil generated by the cutting of preparatory holes is discharged onto the ground. Thereafter, when the soil improving device is pulled out, the solidifying agent is diagonally ejected downward for prior excavation, agitation, and mixing. Subsequently, a blade 9 is widened for further excavation, agitation and mixing. In this way, a plurality of large diameter parts are continuously improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention improves the ground by agitating and mixing the excavated earth and sand of the original ground and the solidifying material in the ground by using a plurality of rotary shafts to make a groundwater stop wall or a retaining wall. The present invention relates to a ground improvement method for forming walls and foundation piles or improving soft ground.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 57805/1992 has been known as a ground improvement method for stirring and mixing a solidifying material injected from a plurality of rotary shafts inserted into the ground and the soil of the original ground. . That is, in this conventional example, a stirring blade is provided at the lower ends of a plurality of rotating shafts, and a soil improvement device provided with a screw portion for soil removal along the entire length of the rotating shafts is used to solidify such as cement milk. Prior to stirring and mixing by injecting the binder, the amount of raw ground soil corresponding to the amount of the binder used is eliminated. In other words, when inserting multiple rotary shafts, the amount of soil that corresponds to the amount of solidifying material that has been determined by the design is determined by the screw part for soil removal, and the rotating shaft is rotated by the stirring blades when the rotating shaft rises. The solidification material sent through the inner space of the ground and the ground soil are agitated and mixed. In this case, the rotation trajectories of the stirring blades provided at the lower ends of the adjacent rotation shafts are partially overlapped in a plan view when inserting or pulling up the plurality of rotation shafts. In the step of inserting the rotary shaft, excavation with a substantially desired diameter is performed.

Further, Japanese Patent Publication No. 4-65165 is known as another ground improvement method for stirring and mixing the solidifying material injected from a plurality of rotary shafts inserted into the ground and the earth and sand of the original ground. . In this conventional example, three excavating shafts are arranged in parallel, each excavating shaft is provided with expandable / contractible stirring means, and spiral parts as stirring parts are provided only on both excavating shafts in the vertical direction of the excavating shaft. Partially provided in part, so that the rotation loci drawn by the stirring means of the adjacent excavating shafts partially overlap each other in a plan view in both cases where the stirring means are reduced in diameter and expanded in diameter. A plurality of excavating shafts are inserted in a reduced diameter state by using a device, and in the ground requiring improvement, the expanding / contracting blades are expanded and a consolidating material is ejected from the tip of the excavating shaft. And excavated earth and sand are mixed by stirring.

[0004]

However, the ground improvement method disclosed in Japanese Patent Publication No. 4-57805 has the same diameter as that of the target ground improvement portion, which is substantially the same as the target ground improvement portion in the step of inserting the rotary shaft when the ground is improved. The excavation hole is formed, part of the excavated soil generated by the formation of the excavation hole is discharged in the step of forming the excavation hole, and the remaining excavated earth and sand and the solidification material are injected while the solidification material is injected when the rotary shaft is pulled up. This is a method in which and are stirred and mixed by a stirring blade. In this way, since the excavation hole of the same diameter as the target ground improvement part is formed in the rotary shaft insertion process, when a large-diameter ground improvement part is to be formed, a large diameter is used in the rotary shaft insertion process. Has to be excavated.
In the case where the rotary shaft is inserted to the target depth without supplying a solidifying material such as cement milk as in the method for ground improvement described in Japanese Patent Publication, the excavated soil is not mudized by the cement milk during insertion. Since a hole with the same diameter as the target ground improvement section is to be excavated, a large amount of power is required to excavate while inserting multiple rotating shafts to a predetermined depth.In particular, rotating multiple rotating shafts is necessary. However, when performing a ground improvement such that a large-diameter columnar ground improvement portion partially overlaps in plan view, the drive device inevitably increases in size,
Not only is the weight heavy and the cost high, but the fact that the driving device that moves up and down along the reader on the ground becomes large and heavy in this way means that the driving device is located above the reader. The stability of the entire device is impaired and there is a risk of the device falling over.

In Japanese Patent Publication No. 4-65165, the expansion / contraction blades are reduced in diameter to form a pilot hole when a plurality of rotary shafts are inserted, and the expansion / contraction blades are expanded in diameter when pulled up to be larger than the pilot holes. It is possible to stir and mix the solidified material and the excavated earth and sand by forming a large-diameter hole, but in this thing, the large-diameter ground improvement section is formed only by the expanded and reduced blades to increase the excavated earth and sand. Since the injected solidification material is mixed with stirring, a large amount of power is required to form a large-diameter ground improvement section by forming the large-diameter hole by forming the large-diameter hole by rotating the rotating shaft and expanding the diameter. There is a problem that it is necessary. Especially when the rotary shaft is multi-axis, it is necessary to rotate a plurality of rotary shafts, so that the drive device becomes large and the weight of the drive device becomes heavy. As a result, even in this conventional example, only the cost becomes high. However, the fact that the driving device that moves up and down along the reader on the ground becomes large and heavy in this way impairs the stability of the entire device when the driving device is located above the reader, and There is a risk of falling.

The present invention has been made in view of the above problems of the prior art, and the main object of the ground improvement method of the present invention is to provide a plurality of large-diameter columnar ground improvement portions in plan view. When performing ground improvement such that some of them overlap with each other, insert a plurality of rotary shafts with small power when inserting a plurality of rotary shafts, and drive a device that rotates multiple rotary shafts when pulling up multiple rotary shafts. A large-diameter ground improvement section can be continuously overlapped in a plan view even if it is not enlarged, and furthermore, stirring and mixing can be effectively performed in each part of the continuous large-diameter ground improvement section. In addition, when a large-diameter ground improvement part partially overlaps in plan view and continues to perform ground improvement, the mixture of excavated soil and solidification material does not overflow to the ground, or even if it overflows, it requires only a small amount of the surrounding environment. Not to worsen In addition, another object is to independently excavate the excavated soil generated at the time of forming each pilot hole by the screw part provided on each rotary shaft when inserting a plurality of rotary shafts to form the pilot hole. Can be continuously discharged to the ground, and multiple pilot holes can be equalized, and the amount of solidified material ejected during the formation of large-diameter ground improvement parts centered on each pilot hole during the lifting process can be controlled. It is to make it easier to equalize the large-diameter ground improvement parts, and another purpose is to easily and surely make the large-diameter ground improvement parts of the desired diameter. To form.

[0007]

In order to solve the problems of the above-mentioned conventional examples and achieve the object of the present invention, the ground improvement method of the present invention comprises a plurality of rotary shafts 1 arranged in parallel to form a ground improvement device. Then, the plurality of rotary shafts 1 of the ground improvement device are inserted into the ground without injecting the solidifying material 2 so that adjacent pilot holes 3 excavated by the adjacent rotary shafts 1 do not overlap in a plan view. After excavating the excavated earth and sand formed laterally apart and not containing the solidified material 2 generated by excavation of the pilot hole 3 to the ground, thus inserting the plurality of rotary shafts 1 to a desired depth,
When pulling up the plurality of rotary shafts 1, the obliquely consolidating material injection portion 8a provided on each rotating shaft 1 injects the consolidating material 2 obliquely downward to precede the ground surrounding each pilot hole 3. When excavating, the excavated soil and the solidifying material 2 are mixed by stirring, and the expansion / contraction blade 9 is continued.
To excavate the ground around each pilot hole 3 and agitate and mix the ground, whereby a plurality of large-diameter grounds in which the excavated soil and the solidifying material 2 are agitated and mixed in the lifting process of the rotary shaft 1. The improvement portions 5 are characterized in that adjacent ground improvement portions 5 are formed so as to partially overlap each other in a plan view.

Further, the lower hole excavating means 7 is provided at the lower end, the expandable and contractible blade 9 is provided on the upper portion of the lower hole excavating means 7, and the solidifying material 2 is jetted obliquely downward to the upper part of the expandable blade 9. A plurality of rotary shafts 1 each having a diagonal solidifying material spraying portion and a screw portion substantially in the upper part of the diagonal solidifying material spraying portion are arranged side by side to form a ground improvement apparatus, and the solidifying material is solidified from the diagonal solidifying material spraying portion. Binder 2
Without injecting water and with the expansion / contraction blades 9 having a reduced diameter, the small-diameter pilot holes 3 are formed while excavating the ground by the pilot hole excavating means 4 provided on the plurality of rotary shafts 1 of the ground improvement apparatus, and the rotary shaft 1 Is rotated in the direction in which the excavated earth and sand are discharged to the ground by the screw portion 6 and the excavated earth and sand generated by the excavation of the pilot hole 3 is discharged to the ground, and thus the rotary shafts 1 are brought to the target depth. After the insertion, when pulling up the plurality of rotary shafts 1, the obliquely solidified material injection portion 8a provided on each rotary shaft 1 injects the solidified material 2 obliquely downward to inject the ground around each pilot hole 3. And the solidified material 2 are agitated and mixed, and then the expansion / contraction blade 9 is expanded in diameter to excavate the ground around each pilot hole 3 and agitated and mixed. A plurality of excavated earth and sand and the solidifying material 2 are mixed by stirring in the pulling up process of 1. Soil improvement unit 5 between adjacent the ground improvement part 5 of larger diameter and is characterized in that formed to partially overlap in plan view.

Further, each rotary shaft 1 is provided with a lateral solidifying material spraying portion 8b for horizontally spraying the solidifying material 2 below an oblique solidifying material spraying portion 8a for spraying the solidifying material 2 obliquely downward, When the rotary shaft 1 is pulled up, the obliquely downwardly-directed solid material injection unit 8 injects the hardened material 2 obliquely downward and the laterally-directed solid material injection unit 8
The solidifying material 2 is jetted laterally from b, the solidifying material 2 jetted obliquely downward and the solidifying material 2 jetted laterally are collided, and the rotation of the collision positions between the solidifying materials 2 is drawn. It is preferable that the radius of the locus is substantially the same as the radius of the rotation locus drawn by the tip of the expansion / contraction blade 9 in the state where the expansion / contraction blade 9 is expanded.

[0010]

According to the above method, however, when the plurality of rotary shafts 1 of the ground improvement device are inserted into the ground, the ground is excavated without injecting the solidifying material 2 and they do not overlap each other in a plan view. The small-diameter pilot hole 3 is formed, and the excavated earth and sand generated by excavating the pilot hole 3 is discharged to the ground. As a result, when the plurality of rotary shafts 1 are inserted into the ground, the pilot holes 3 can be formed as small as possible and independently at the same time even if the solidifying material 2 is not jetted. The pilot holes 3 are made uniform and the excavated sand from each pilot hole 3 is discharged uniformly. After that, when pulling up the ground improvement device, the solidified material 2 is jetted obliquely downward from the diagonal solidified material jetting portion 8a provided on each rotary shaft 1 to excavate the ground around each pilot hole 3 in advance. At the same time, the excavated soil and the solidifying material 2 are stirred and mixed, and then the expansion / contraction blade 9 is expanded in diameter to excavate the ground around each prepared hole 3 and also stirred and mixed, whereby the rotary shaft 1 is pulled up. By forming a plurality of large-diameter ground improvement portions 5 in which the excavated soil and the solidifying material 2 are mixed by stirring so that adjacent ground improvement portions 5 partially overlap each other in plan view, they do not overlap each other. When excavating the ground around each pilot hole 3 to form a large-diameter ground improvement portion 5 in which adjacent ones overlap each other, the solidifying material 2 is jetted obliquely downward to lead the ground downward. Since the ground around the hole 3 is excavated,
It is not necessary to increase the rotational power of the rotary shaft 1 for excavation by the expanded blade 9 having a large diameter, and the ground improvement section 5 having a large diameter is used.
The drive device 11 for rotating the multi-axis rotary shaft 1 for improving the ground such that the two partially overlap each other in plan view does not have to be so large. When excavating the pilot hole 3, the excavated soil that does not contain the solidified material 2 generated by excavating the pilot hole 3 is discharged to the ground. Therefore, the excavated soil generated when the pilot hole 3 is formed is discharged. Only minutes
It is possible to reduce the amount of the mixture of the solidifying material 2 and the excavated soil overflowing the ground in the pulling up process, or to prevent the mixture from overflowing to the ground. Moreover, before the pulling up, the ground around the pilot hole 3 is removed. Since the solidifying material 2 for excavating is jetted obliquely downward, even if it is pulled up to the vicinity of the surface of the earth, it does not blow up the earth and sand near the surface of the earth to the ground by the injection, so that the surrounding environment is not deteriorated. . That is, in the present invention, the mixture of the excavated earth and the congealing liquid is prevented from overflowing to the ground as much as possible, and when the rotary shaft is pulled up to reduce the size of the drive unit, the consolidating material is sprayed to form a pilot hole. Despite the fact that the surrounding ground is to be excavated in advance, it prevents the soil on the surface ground from being ejected to the ground by the injection of the solidifying material, which is a means for excavating in advance. The working environment in can be improved. Further, since the solidifying material 2 is sprayed obliquely downward from above the expanding / contracting blade 9, the excavated soil and the solidifying material 2 can be effectively stirred and mixed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 shows an embodiment of the apparatus used in the present invention. A leader (not shown) is erected on a construction machine (not shown) installed on the ground, and the drive device 11 is hung vertically on the leader, and the drive device 11 is provided with a plurality of rotary shafts 1. It is attached via the device 12. For example, as shown in FIG. 1, a plurality of rotary shafts 1 are arranged side by side in a row in the lateral direction, and a bit forming a pilot hole excavating means 7 is provided at the lower end of each rotary shaft 1. A large diameter excavation means 4 is formed above the lower hole excavation means 7 of the rotary shaft 1. The large-diameter excavation means 4 is composed of expandable / contractible blades 9 and a cement injection 8 for injecting the cement 2 such as cement milk or cement milk as a main component. .

As shown in FIGS. 4 and 5, the expandable / reducible expansion / contraction blade 9 is provided with a mounting portion 13 on the rotary shaft 1, and the mounting portion 1
3, one end of the stirring member 14 is rotatably attached to the expansion / contraction blade 9. The mounting portion 13 is composed of vertical projections 13a and 13b facing each other in the vertical direction and a central column portion 13c formed between the vertical projections 13a and 13b by cutting the side surface into an L shape. The stirring member 14 is configured by rotatably supporting an inner member 16 and an outer member 17 with a shaft 18, and the inner member 16 is provided near a pair of diagonally opposed corners of the vertical protrusions 13a and 13b. The rear end of the pivot shaft 19
Is pivoted by. Here, the stopper protrusion 2 is provided on each of the side surfaces of the inner member 16 and the outer member 17, respectively.
0 and 21 are projected. At the tip of the outer member 17, a projection 23 is provided so as to project in at least one of the vertical direction, and in the embodiment, both upward and downward. A blade portion 24 is provided on the protrusion 23 as needed.

The expansion / contraction blade 9 in the state shown in FIG. 4 (a) is in a state in which the expansion / contraction blade 9 is expanded, and in the state in FIG. 4 (b) is in a state in which the expansion / contraction blade 9 is reduced in diameter. When the rotary shaft 1 is rotated in the direction of arrow a, one side surface 53 of the inner member 16 is a contact surface 25 which is one side surface portion of the L-shaped side surface of the central column portion 13c.
Then, the inner member 16 is kept in the expanded diameter state. In this case, the contact portion 20a of the stopper projection 20 of the inner member 16 further abuts the outer surface portion 27 of the central column 13c as shown in FIG. 4A, so that the expanded diameter state of the inner member 16 is further maintained. Become. Further, the outer member 17 and the inner member 16 are substantially in a straight line when the diameter is expanded, and in this state, the opposing end surfaces of the stopper projections 20 and 21 are in contact with each other as shown in FIG. Holding in this way,
The state in which the inner member 16 is expanded and the outer member 17 is expanded so that the inner member 16 and the outer member 17 are substantially in a straight line is a state in which the expansion blade 9 is expanded.

On the other hand, when the rotary shaft 1 is rotated in the direction of arrow B in FIG. 4A, the stirring member 14 rotates in the direction of arrow C due to the resistance of the earth and sand, and the state of FIG. 4B (that is, the inner member 16).
The other side surface 28 contracts against the contact surface 25 of the central column portion 13c and stops), and the outer member 17 rotates with respect to the inner member 16 so that the projection 23 extends from the upper projection 13a to the lower projection. The inner member 16 and the outer member 17 hit the outer surface of 13b and are bent into a substantially V shape around the rotary shaft 1, and this state is the reduced diameter state of the expansion / contraction blade 9. In the reduced diameter state of the expansion / contraction blade 9, the outer member 17 and the rotary shaft 1
A space 29 for introducing earth and sand is formed between the outer surface and the outer surface (that is, the other side surface of the L-shaped notch of the central column 13c). Therefore, as shown in FIG. 4 (b), when the expansion / contraction blade 9 is bent in a V shape around the rotating shaft 1 and the diameter thereof is reduced, when the rotating shaft 1 is rotated in the direction of arrow a, the resistance of the soil first causes the outside to rotate. The member 17 rotates in the direction of arrow D, and the inner member 16 also rotates in accordance with the rotation of the outer member 17 in a state where the facing surfaces of the stopper protrusions 20 and 21 are in contact with each other, and the expansion / contraction blade 9
The diameter can be increased. In this way, when the rotary shaft 1 is rotated in the reverse direction to expand the expansion / contraction blade 9, the projection 23 is provided, so that not only the tip of the outer member 17 but also the projection 23 is soiled when expanding the diameter. The resistance of the soil is large and the outer member 17 is easily opened. Further, at this time, the earth and sand enter the space 29 for introducing sand and the outer member 17 is rotated by the resistance of the soil to be easily opened. Is. The diameter of the rotation locus drawn by the expansion / contraction blade 9 with the diameter of the expansion / contraction blade 9 reduced is equal to or smaller than the diameter of the rotation locus drawn by the pilot hole excavating means 7.

The rotary shaft 1 is provided with an oblique consolidation material injection portion 8a for injecting the consolidation material 2 obliquely downward above the expansion / contraction blade 9. Further, in the embodiment shown in FIG. 1, a horizontal binding material injection portion 8b for injecting the binding material 2 laterally between the oblique binding material injection portion 8a of the rotary shaft 1 and the expansion / contraction blade 9.
Is provided. The jet flow of the solidifying material 2 jetted obliquely downward from the diagonal solidifying material jetting part 8a and the jetting flow of the solidifying material 2 jetted laterally from the lateral solidifying material jetting part 8b directly intersect with each other. The injection direction from each solidifying material injection unit 2 is determined so as to collide with each other, and the diameter of the rotation locus drawn at this intersecting position is made substantially equal to the diameter of the rotation locus in the expanded state of the expansion / contraction blade 9. There is. In addition, in the embodiment, the embodiment is shown in which the horizontal direction solidifying material spraying unit 8b sprays the solidifying material 2 in a substantially horizontal direction. The fuel may be injected obliquely upward or obliquely downward at a gentle angle with the horizontal direction. In any case, it is set so that the jet flow of the solidifying material 2 jetted from the oblique solidifying material jetting portion 8a and the solidifying material 2 jetted from the lateral solidifying material jetting portion 8b directly intersect and collide with each other. As described above, in the present embodiment, the solidifying material ejecting portion 8 is composed of the obliquely solidifying material ejecting portion 8a and the laterally-directed solidifying material ejecting portion 8b.

Further, in this embodiment, the large-diameter excavating means 4 is constituted by the solid material injection portion 8 provided on the rotary shaft 1 and the expandable / contractible blade 9. On the rotary shaft 1, a screw portion 6 is provided in almost the entire upper portion of the large-diameter excavation means 4. That is, the screw portion 6 is provided in almost the entire region from a position immediately above the obliquely consolidating material injection portion 8a located at the uppermost position of the members forming the large-diameter excavating means 4 of the rotary shaft 1. The screw part 6 is provided on all of the plurality of juxtaposed rotary shafts 1, and the rotation loci of the screw parts 6 provided on the adjacent rotary shafts 1 are set so as not to overlap each other in plan view,
In the embodiment, the diameter of the rotation locus of the screw portion 6 is set to be equal to or smaller than the diameter of the rotation locus of the pilot hole excavating means 7.

The plurality of rotary shafts 1 are connected by a vertical plate-shaped connecting member 30 to prevent the intervals between the rotary shafts 1 from widening or narrowing. The connecting member 30 is rotatably attached to the rotary shaft 1 by a bearing 31 in the rotary shaft 1 portion, and a space between the bearing portions 31 has a vertical plate shape. The vertical plate portion 32 between the bearing portions 31 is provided with an injection portion 34 for injecting air or water 33 downward to facilitate the insertion of the connecting member 30. Reference numeral 35 in the figure denotes a hose connected to the injection unit 34 for supplying air and water.

A ground improvement section 5 is formed in the ground by using the apparatus having a structure in which a plurality of rotary shafts 1 are arranged side by side as described above. A construction example will be described below. First, as shown in FIG. 2A, each rotary shaft 1 is rotated in a state in which the solidifying material 2 is not jetted from the solidifying material jetting portion 8 and a plurality of expansion / contraction blades 9 provided above and below are reduced in diameter. While drilling means 7
A plurality of small-diameter pilot holes 3 that do not overlap with each other in plan view are formed by excavating with the excavating bit that constitutes the above-mentioned No. 1 to insert a plurality of rotary shafts 1 to a desired depth in the ground. When the rotary shaft 1 is inserted to a predetermined depth, the rotary shaft 1 is easily inserted while jetting air or water downward from the pilot hole excavating means 7, and the air or water 33 is jetted downward from the jetting part 34. It is also possible to facilitate the insertion of the connecting member 30 between the rotary shafts 1 while injecting toward. Of course, the plurality of rotary shafts 1 may be inserted to a predetermined depth by excavating the pilot hole excavating means 7 without jetting air or water.

By the way, in the present invention, when excavating the pilot hole 3 while excavating the ground by the pilot hole excavating means 7 while rotating the plurality of rotary shafts 1, above the pilot hole excavating means 7 of each rotary shaft 1. The excavated earth and sand containing no solidified material 2 excavated by the pilot hole excavation means 7 is discharged to the ground by the screw portion 6 formed in almost the entire position. In this case, the excavated earth and sand discharged to the ground are discharged only when excavating the pilot hole 3 while ejecting air, or when excavating without ejecting air or water, only the excavated earth and sand are ejected, When excavating the hole 3, excavated soil containing water is discharged to the ground. The excavated soil discharged to the ground is used as soil as it is or after it has been dried to remove water, and is then disposed of as soil. The excavated soil is a solidifying material such as cement milk. Since it is not mixed with 2, it can be reused and disposed of easily and at low cost.

By the way, according to the present invention, a plurality of small-diameter pilot holes 3 formed by inserting a plurality of rotary shafts 1 into the ground are such that adjacent pilot holes 3 are mutually adjacent as shown in FIG. 2 (d). The holes are formed so as not to overlap in a plan view, and have a narrow width formed between the adjacent pilot holes 3 of the small holes (that is, the width is much narrower than the diameter of the pilot hole 3). ) A narrow groove 36 is formed.

As described above, after inserting the plural rotary shafts 1 to a predetermined depth in the ground to form the pilot holes 3 having a small diameter in the ground, the plural rotary shafts 1 are formed as shown in FIG. 2 (b). The rotary shafts 1 are pulled up. When the plurality of rotary shafts 1 are pulled up, in the present invention, in the present invention, the obliquely consolidating material jetting portions 8a respectively provided on the respective rotary shafts 1 and the laterally consolidating portions located below them are provided. The solidified material 2 is injected from the material injection section 8b, and the expansion / contraction blades 9 provided on the plurality of rotary shafts 1 are expanded in diameter to rotate the rotary shaft 1 and pull it upward.

Then, as the rotary shaft 1 is pulled up, the ground around the pilot hole 3 is first excavated and agitated by the injection pressure of the solidifying material 2 injected from the upper oblique solidifying and spraying portion 8a. Then, the ground is excavated and stirred by the solidifying material 2 sprayed in a substantially horizontal direction from the lateral solidifying material spraying unit 8b, and subsequently,
The ground is excavated and agitated and mixed by the expansion / contraction blade 9 located below.

Here, the jet flow of the solidifying material 2 jetted obliquely downward from the diagonal solidifying material jetting portion 8a and the solidifying material 2 jetted substantially horizontally from the lateral solidifying material jetting portion 8b. The direct collision with the jet flow causes the jetting energy to be attenuated. As a result, the solidified jets from the upper and lower solidifying material jet parts 8a and 8b about the rotary shaft 1 are centered. The prototype of the columnar ground improvement body 5 having a large diameter whose radius is the distance to the collision portion of the binder 2 is formed in advance. By the way, at this time, following the excavation by the consolidating material 2 injected from the oblique consolidating material injecting portion 8a, stirring and mixing, the excavation by the consolidating material 2 injected from the lateral consolidating material injecting portion 8b, and stirring and mixing, The expanded blades 9 having an expanded diameter are used for excavation and stirring and mixing. At this time, the jet flow of the solidifying material 2 jetted obliquely downward from the diagonal solidifying material jetting section 8a and the lateral solidifying material jetting section 8b. Since the diameter of the rotation locus drawn at the intersecting position where the jet flow of the solidifying material 2 directly jetted from the horizontal direction is approximately equal to the diameter of the rotation locus in the expanded state of the expansion / contraction blade 9, When excavating and stirring and mixing by the expansion and contraction blades 9 provided on the rotary shaft 1, the excavation of the ground around the prepared hole 3 by the expansion and contraction blades 9 injects obliquely downward to inject the solidified material.
Due to the preceding excavation, the unexcavated portion is to be excavated, and the plurality of rotary shafts 1 are rotated even though the expansion / contraction blades 9 provided on the plurality of rotary shafts 1 are expanded to excavate a large diameter. It is not necessary to increase the size of the driving device 11 for downsizing, and the driving device 11 can be downsized. As a result, the weight of the driving device 11 is reduced, and even when the driving device 11 for moving the reader up and down on the ground is located above the reader, It eliminates the risk of falling. This series of excavation and stirring / mixing is shown in a schematic diagram as shown in FIG. 3. By raising the rotary shaft 1, a large-diameter columnar ground having a desired diameter can be easily and accurately improved. The part 5 can be formed.

In the above-mentioned excavation, the projection 23 is projected upward at the tip of the expansion / contraction blade 9, and the blade 24 is provided on the projection 23 projected upward. The ground is excavated by the blade portions 24 of the projections 23 prior to the expansion / contraction blade 9 during the pulling up, and the excavation becomes easier. In addition, by providing the protrusion 23 upward or downward at the tip of the expansion / contraction blade 9, stirring,
Good mixing can be achieved.

As described above, a plurality of large-diameter ground improvement portions 5 filled with a mixture of excavated soil and solidifying material 2 are continuously formed while pulling up the plurality of rotary shafts 1.
Here, when forming the large-diameter ground improvement portion 5 while rotating the rotary shaft 1 and pulling it up, even if the solidifying material spraying portion 8 is pulled up to near the ground surface, the upper and lower solidifying material spraying portions 8 By causing the jets of the solidifying material 2 jetted from the jets to join together after the collision so that the jetting direction is directed obliquely downward (in the embodiment shown in the accompanying drawings, obliquely downward from the oblique solidifying material jetting portion 8a). When the solidified material 2 sprayed on the surface and the solidified material 2 sprayed from the lateral solidified material spraying portion 8b merge after the collision, the direction after the merge is diagonally downward), and the ground near the ground surface is upward. There is no risk of swelling or the solidifying material 2 or the earth and sand ejecting to the ground, causing the solidifying material 2 or the earth and sand to collide with an operator on the ground and injuring, or the solidifying material 2 or the earth and sand around the ground. Will not scatter and damage the surrounding environment. Further, when the solidifying material injection unit 8 is pulled up to the ground, the solidifying material 2
Even if the solidified material 2 is being sprayed, the sprayed area after the merger is directed obliquely downward, so the spraying area is narrow, and the solidifying material 2 collides with the workers in the surrounding area, or the solidifying material 2 scatters around. It is supposed not to. Of course, in the present invention, the ground improvement portion 5 can be formed only in a portion of an arbitrary depth underground in the step of pulling up the plurality of rotary shafts 1.

In the present invention, since the excavated earth and sand containing no solidifying material 2 generated by excavating the pilot hole 3 is discharged to the ground by the screw portion 6 when the pilot hole 3 is formed, the pilot hole 3 is formed. The amount of excavated earth and sand generated during the excavation (a large part of the excavated earth and sand generated during excavation of the pilot hole 3 or a part of the excavated earth and sand is excavated), and the solidifying material 2 in the pulling process It is possible to reduce the amount of the mixture of slag and excavated soil that overflows to the ground or prevent it from overflowing to the ground. Therefore, it is possible to reduce the amount of the mixture of the solidifying material 2 and the excavated earth and sand overflowing on the ground or prevent the mixture from overflowing to the ground, so that the working environment is not deteriorated, and the solidifying material 2 and the excavation material are excavated. Even if the mixture with earth and sand sometimes overflows on the ground, it is a small amount, so that it can be easily disposed of as industrial waste and the cost required for disposal can be reduced.

As described above, the mixture of the excavated soil and the congealing liquid is prevented from overflowing to the ground as much as possible, and the consolidating material 2 is removed when the rotary shaft 1 is pulled up in order to downsize the drive unit 11. Despite the fact that the ground around the pilot hole 3 is previously excavated by jetting, the injection of the solidifying material, which is a means for excavating first, prevents the earth and sand of the ground surface from being jetted to the ground, By these things,
It improves the working environment on the ground.

As described above, the large-diameter columnar ground improvement portion 5 filled with the mixture of the excavated soil and the solidifying material 2 is formed while pulling up the rotary shaft 1. After the rotary shaft 1 is completely pulled out, similarly, large-diameter columnar ground improvement portions 5 are successively formed. In this case, the ground improvement part 5 is formed continuously (may be partially overlapped) to form a water blocking wall or a mountain retaining wall. Of course, by forming the ground improvement section 5 to form a foundation pile,
You may improve soft ground.

By the way, in the present invention, as described above, the adjacent pilot holes 3 excavated by the adjacent rotary shafts 1 are formed laterally apart from each other so that they do not overlap each other in plan view,
A plurality of large-diameter ground improvement portions 5 formed around each pilot hole 3
Since the adjacent ground improvement portions 5 are formed so as to partially overlap each other in a plan view, the diameter of the large diameter ground improvement portion 5 can be set large without being restricted by the diameter of the pilot hole 3. The diameter of the pilot hole 3 can also be set as small as possible. Therefore, even when the pilot hole 3 is formed, a small amount of power is required, and in particular, when the pilot hole 3 is formed, the consolidation material 1 is not sprayed, and the pilot hole excavating means 7 is not sprayed with air or water. In the case of forming the pilot hole 3 only with a certain drill bit, this can be easily done with a small power, and the cost for forming the pilot hole 3 can be reduced.

Although an example of three axes is shown in FIG. 1 as a multi-axis embodiment, the number of axes is not limited to three and may be two or four or more. The point is that it is multi-axis. In the embodiment shown in the accompanying drawings, all of the plurality of expandable / contractible expansion / contraction blades 9 are reduced in diameter by the rotation of the rotary shaft 1 in one direction (forward direction) and in the other direction (reverse direction) of the rotary shaft 1. Although an example of a structure in which the diameter is expanded by rotation is shown, the expansion / contraction may be performed by a hydraulic cylinder or other expansion / contraction drive device (not shown).

In the above embodiment, the stirring member 14 as the expansion / contraction blade 9 is an example in which the inner member 16 and the outer member 17 are rotatably supported by the shaft 18, but by doing so, The diameter when the diameter is reduced can be made smaller, and the diameter when the diameter is enlarged can be made larger. In addition, the stirring member 14 has the inner member 16 and the outer member 17 as in the embodiment.
The inner member 16 is not limited to the one that is pivotally supported.
Of course, the outer member 17 and the outer member 17 may be integrated.

Further, in the above-mentioned embodiment, an example in which the lateral solidifying material spraying portion 8b is provided below the oblique solidifying material spraying portion 8a has been shown, but the horizontal solidifying material spraying portion 8b may not be provided.
In any of the embodiments of the present invention, the solidified material 2 to be jetted may be jetted into the ground with fibers such as steel fibers and synthetic resin fibers mixed therein. In this case, if the fibers used are steel fibers, the length is several centimeters (for example, 3
.About.6 cm) and a diameter of about 0.3 to 1.5 mm is used, and if necessary, the ends of the fibers are bent to form bent portions. Of course, the length, diameter and shape are not limited to those described above. Thus, in the case of injecting the consolidation material 2 in which fibers are mixed, the fibers are mixed in the ground improvement body to be formed, so that the ground improvement body having higher strength can be formed. In this case, in particular, since the fibers are mixed in the solidified material 2 ejected at the time of pulling up, compared to the case where the solidified material containing fibers is ejected at the time of insertion, the fibers are only below the vicinity of the lower end of the rotating shaft being pulled up. Since the fibers are not located, the influence of the fibers as a resistance for pulling up the rotary shaft 1 can be reduced, and the workability is improved.

[0033]

According to the first aspect of the present invention, as described above, the plurality of rotary shafts of the ground improvement device are inserted into the ground without injecting the solidifying material and the adjacent rotary shafts are rotated. Adjacent holes to be excavated by the shaft are formed so as to be separated laterally so that they do not overlap in plan view, and excavated earth and sand containing no consolidation material generated by the excavation of holes is discharged to the ground. After inserting multiple rotary shafts to the target depth,
When pulling up a plurality of rotary shafts, the obliquely downwardly consolidating material is injected from the obliquely consolidating material spraying unit provided on each rotating shaft to diagonally downwardly excavate the ground around each pilot hole and excavate earth and sand. And the stirrer are mixed by agitation, and then the expansion and contraction blades are expanded in diameter to excavate the ground around each pilot hole and stir and mix. Since a plurality of large-diameter ground improvement portions mixed by stirring are formed so that adjacent ground improvement portions partially overlap with each other in plan view, the pilot holes can be formed as small as possible and can be formed independently at the same time. The pilot holes are equalized and the excavated soil from each pilot hole is discharged uniformly. As a result, the large-diameter columnar ground improvement part formed around the pilot holes is partially seen in plan view. When performing ground improvement that overlaps, from each axis in the post process Managing Katayuizai injection are those that can be formed continuously ground improvement of easy and uniform diameter.
Moreover, when excavating the ground around each pilot hole that does not overlap with each other to form a large-diameter ground improvement part in which adjacent ones overlap each other, a consolidating material is sprayed diagonally downward. Since the ground around the pilot hole is excavated ahead of time, when excavating, the consolidating material that is injected diagonally downward does not leave the unexcavated portion when excavating with a large-diameter expanding / contracting blade, which was performed prior to large-diameter excavation. It suffices to excavate, and it is not necessary to increase the rotational power of the rotating shaft in the state where the expansion / contraction blade is expanded,
The large-diameter ground improvement portion does not have to be so large as a drive device for rotating a multi-axis rotary shaft for ground improvement such that the ground improvement portions partially overlap each other in plan view, and as a result, Even if the drive device for raising and lowering the reader is located above the reader, the stability of the device is not impaired, and the risk of the device tipping over on the ground can be prevented. In addition, when excavating the pilot hole, excavated earth and sand that does not contain solidification material generated by excavation of the pilot hole is discharged to the ground.Therefore, only the amount of the excavated earth and sand generated during the formation of this pilot hole is lifted. It is possible to reduce the amount of the mixture of the solidifying material and the excavated soil overflowing to the ground or to prevent it from overflowing to the ground, and to excavate the ground around the pilot hole before pulling up. Since the solidifying material is sprayed obliquely downward, even if it is pulled up to near the surface of the earth, it does not blow up the earth and sand near the surface of the earth to the ground. As a result, according to the method of the present invention, the mixture of the excavated earth and the congealing liquid is prevented from overflowing to the ground as much as possible, and by the injection of the consolidating material at the time of pulling up the rotary shaft for downsizing the drive unit. Despite the fact that the ground around the pilot hole is to be excavated in advance, it prevents the earth and sand from being ejected to the ground by the injection of the solidifying material, which is a means for excavating in advance. As a result, the working environment on the ground can be improved. Further, in the present invention, since the solidifying material is injected obliquely downward from above the expanding / contracting blade, the excavated earth and sand and the solidifying material are injected by the composite stirring and mixing action of the solidifying material injection and the expanding / expanding blade having the increased diameter. The stirring and mixing can be effectively performed.

Further, in the invention described in claim 2 of the present invention, in addition to the effect described in claim 1, further, when a plurality of rotary shafts are inserted to form the pilot hole, each rotary shaft is attached to each rotary shaft. Excavated earth and sand generated at the time of forming each pilot hole can be independently discharged continuously to the ground by the provided screw part, and a plurality of pilot holes are equalized, and each pilot hole in the pulling process is centered. When forming a large-diameter ground improvement portion, the amount of the solidified material ejected can be easily controlled, and the large-diameter ground improvement portions can be equalized.

Further, in the invention according to claim 3 of the present invention, in addition to the effect of the invention according to claim 2 or claim 3, a consolidating material is jetted obliquely downward to each rotary shaft. Provided below the diagonal solidifying material jetting section is a horizontal solidifying material jetting section for jetting the solidifying material laterally, and jetting the solidifying material diagonally downward from the diagonal solidifying material jetting section when the rotary shaft is pulled up. Along with this, the horizontal solidifying agent is sprayed laterally from the horizontal solidifying material jetting unit, and the solidifying material jetted obliquely downward and the laterally jetted solidifying material are collided with each other. The radius of the drawn rotation trajectory is made almost the same as the radius of the rotation trajectory drawn by the tip of the expansion / contraction blade when the expansion / contraction blade is expanded. Is something that can be done.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of an embodiment of an apparatus used in the present invention.

2 (a), (b) and (c) are explanatory views showing a construction order of the present invention, and (d) is a sectional view in the case of (a),
(E) is sectional drawing in the case of (b).

FIG. 3 is a diagram for explaining the operation of the same.

4 (a) and 4 (b) are cross-sectional views showing a diameter-expanded state and a diameter-reduced state of the same expansion / contraction blade, respectively.

FIG. 5 is a diameter expansion front view of the expansion / contraction blade.

[Explanation of symbols]

 1 rotating shaft 2 solidifying material 3 lower hole 4 large diameter excavating means 5 ground improvement section 6 screw section 7 lower hole excavating means 8 solidifying material injection section 9 expansion / contraction blade

Claims (3)

[Claims] 1. A ground improvement device is constructed by arranging a plurality of rotation shafts in parallel, and the plurality of rotation shafts of the ground improvement device are inserted into the ground without injecting a solidifying material and excavated by adjacent rotation shafts. The adjacent pilot holes are formed laterally apart from each other so that they do not overlap in plan view, and the excavated earth and sand that does not contain solidification material generated by the pilot hole excavation is discharged to the ground. After inserting the shafts to the target depth, when pulling up multiple rotating shafts, the obliquely downward direction of the solidified material is injected from the obliquely solidified material injection unit provided on each of the rotating shafts, and the circumference of each pilot hole Of the ground is first excavated, and the excavated soil and the solidifying material are agitated and mixed, and then the expansion and contraction blades are expanded in diameter to excavate the soil around each pilot hole and agitated and mixed. Multiple large-diameter grounds in which excavated soil and solidifying materials were mixed by stirring in the lifting process A ground improvement method, characterized in that adjacent ground improvement portions are formed so as to partially overlap each other in a plan view. 2. An oblique consolidation material injection in which a lower hole excavating means is provided at a lower end, an expandable / contractible expansion blade is provided on an upper part of the lower hole excavating means, and a consolidating material is injected obliquely downward to the upper part of the expanding / contracting blade. A ground improvement device is constructed by arranging a plurality of rotary shafts provided with a screw portion in substantially the entire upper portion of the diagonal solidifying material injection unit, and injecting the solidifying material from the diagonal solidifying material injection unit. With the diameter of the expansion and contraction blades reduced, a small-diameter pilot hole is formed while excavating the ground by the pilot hole excavating means provided on the rotary shafts of the ground improvement device, and the rotary shaft is excavated by the screw part on the ground. When excavating the excavated earth and sand generated by excavating the pilot hole by rotating in the direction of earth removal and inserting a plurality of rotating shafts to the target depth in this way, when pulling up a plurality of rotating shafts , The slanted solidified material is obliquely injected from the slanted solidified material injection part provided on each rotary shaft. Injecting downward to excavate the ground around each pilot hole in advance, agitate and mix the excavated soil and solidifying material, and subsequently expand the expansion / contraction blade to excavate the ground around each pilot hole. And agitating and mixing, whereby a plurality of large-diameter ground improving portions in which the excavated soil and the solidifying material are agitated and mixed in the pulling-up process of the rotating shaft are partially overlapped in adjacent ground improving portions. A method for improving the ground, which is characterized in that 3. A horizontal consolidating material spraying unit for laterally spraying the solidifying material is provided below each diagonal solidifying material spraying unit for spraying the solidifying material obliquely downward on each rotary shaft, and when the rotary shaft is pulled up. The obliquely consolidating material spraying unit ejects the consolidating material obliquely downward and the sideways consolidating material ejecting unit ejects the consolidating material sideways, and the obliquely downward consolidating material is ejected sideways. It is characterized in that the radius of the rotation trajectory drawn by the collision position of these solidification materials is made almost the same as the radius of the rotation trajectory drawn by the tip of the expansion blade when the expansion blade is expanded. The ground improvement method according to claim 1 or 2.