JPH08199556A - Soil improvement device - Google Patents

Abstract

PURPOSE: To make it possible to uniformly stir and mix excavated soil and hardener with simple change by extending stirring wings in the radial direction to the front part of a stirring rod, and mounting vertically shearing auxiliary wings extending along the roughly axial direction of the rod to one of the stirring wings. CONSTITUTION: Vertically shearing auxiliary wings 11 extending along the roughly axial direction of the rod 1 are mounted to at least one of stirring wings 3A-3C. Excavated soil and hardener are effectively stirred and mixed by shearing the excavated soil in the vertical direction by the vertically shearing stirring wings 11 in addition to the horizontal shear by the stirring wings 3A-3C. The end face is made as an edge-shape, clayey excavated soil is also easily cut off finely by using a planar orienting direction as a tangential direction. A stirring rod 1 is made as a rod body 1 of double pipe construction formed of an inside pipe 7 and an outside pipe 8, and by revolving the inside pipe 7 and outside pipe 8 in the direction opposed to each other, earth and sand are stirred and mixed in a sate to prevent common rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement device used in a mixing treatment method for forming a solidification improving body in the ground by stirring and mixing a solidifying material and earth and sand at the present position,
Particularly, it relates to the stirring rod structure.

[0002]

2. Description of the Related Art For example, ground improvement for landfills, roads,
For ground improvement in land reclamation work, a mixing treatment method that mainly adds lime or a cement-based chemical solidifying material to the soil and solidifies it by forcibly stirring and mixing to increase the ground strength is often used because of its usefulness. Has been adopted.

The above-mentioned mixing treatment method has relatively flexibility in the shape and strength of the improved ground, can be applied to various grounds under different water depth conditions, ground conditions, etc., and is economical, and cement added to the ground Since the amount of slurry is small and the amount of embankment accompanying it is small, it has little effect on existing structures, and since there is little vibration and noise during construction, it is a construction method suitable for ground improvement in urban areas. Have advantages.

The structure of the stirring blade of the ground improvement apparatus used in the mixing treatment method will be described with reference to FIG. The digging blade 2 has a structure in which the outer tube 8 is provided with stirring blades 3 and 3. The digging blade 2 is a tip digging blade 4 having a small rotation diameter and a rotation arranged at a predetermined distance above the tip digging blade 4. The excavating blade 5 also has a large diameter and is used as a stirring blade. The stirring and excavating blade 5 is also formed in a dragonfly shape including a left blade 5a and a right blade 5b. The stirring blade 3 provided on the outer tube 8 is also composed of two blades, a left blade 3a and a right blade 3b, like the stirring and excavating blade 5, and the plurality of stirring blades 3 and 3 are arranged in the vertical direction. It is general that they are separated by a predetermined distance, and are arranged in a plurality of stages with a 90-degree offset in plan view.

[0005]

As described above, by constructing the stirring rod as a double pipe structure consisting of an inner pipe and an outer pipe, and rotating the excavating blade and the stirring blade in opposite directions,
The co-rotation phenomenon can be suppressed, and the excavated soil and the solidified material can be mixed much more effectively than when the excavating blade and the stirring blade are rotated in the same direction.

However, in the case of the conventional stirring blade structure, the soil is stirred by the bar-shaped stirring blades extending in the radial direction (horizontal direction) provided at appropriate intervals in the vertical direction. The mechanism is to stir the improved soil by shearing it horizontally. Therefore, the excavated soil may remain in the form of a long block in the horizontal direction without being divided, and it cannot be said that sufficient stirring and mixing are still performed. This tendency is particularly remarkable when the target soil is cohesive soil.

On the other hand, in recent years, as shown in FIG. 8, a double ring structure has been adopted in which a small stirring blade body 31 is located inside the large stirring blade body 30 below the inner pipe 7 and the outer pipe 8. Stirring blades have been developed that rotate in opposite directions.

In this case, although it is desired to uniformly stir the stirred sand, the conventional general stirring blade is completely different from the blade structure, and it has to be manufactured completely.

Therefore, an object of the present invention is to make it possible to uniformly stir and mix the excavated soil and the solidifying material by simply making a simple change to the conventional stirring blade structure, and there is no variation in the consolidation strength. An object of the present invention is to provide a ground improvement device capable of forming a new improved body.

[0010]

In order to solve the above-mentioned problems, the present invention relates to a ground improvement apparatus having a stirring blade extending in a radial direction at a tip portion of a stirring rod, and at least one of the stirring blades. On the other hand, it is characterized in that a vertical shearing auxiliary blade extending substantially along the axial direction of the rod is attached.

In this case, it is desirable that the stirring blade to which the vertical shearing auxiliary blade is attached is a lowermost stirring blade or a combination including the lowermost stirring blade. Further, by making the end face of the vertical shearing auxiliary blade into a blade shape and further by making the planar orientation direction the tangential direction, it is possible to effectively reduce the shear resistance and to cut the soil mass in the vertical direction.

Further, the stirring rod is a rod body having a double pipe structure composed of an inner pipe and an outer pipe, and the inner pipe and the outer pipe are rotated in opposite directions to each other so that the earth and sand do not rotate together. Can be stirred and mixed.

Further, a digging blade is provided at the tip of the inner pipe, and a plurality of stirring blades are provided at the tip of the outer pipe located on the upper side of the digging blade so as to form a step in the rod axial direction. It is possible to configure the tip digging blade and the agitating digging blade located on the upper side of the tip digging blade, and provide the lowermost stirring blade with a plurality of vertical shearing auxiliary blades directed toward the tip side in the rod axial direction.

[0014]

In the present invention, a vertical shearing auxiliary blade extending substantially along the axial direction of the rod is attached to the stirring blade. In the case of the conventional stirring blade, the excavated soil and the solidified material are mainly stirred and mixed by the horizontal shearing, but in the case of the present invention, in addition to the horizontal shearing by the stirring blade, the vertical shearing Since the excavated soil is sheared in the vertical direction by the stirring blade, the excavated soil and the solidified material can be effectively stirred and mixed, and the obtained improved body is also a good improved body with no variation in strength. can do. In this case, the end face is blade-shaped,
By setting the planar orientation direction to be the tangential direction, it becomes possible to easily cut finely the clayey excavated soil, which could not be conventionally cut.

Further, in the case of the present invention, since it suffices to attach the stirring blade for vertical shearing to the stirring blade, the manufacturing cost is low and the change can be easily made without any trouble.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.
As shown in FIG. 1, the ground improvement device used in the mixed processing method is a power swivel that is movable along the leader 21 on a leader 21 fixed in an upright state with respect to a base machine 23. 20 is mounted and the stirring rod 1 is connected via a reduction gear.

The stirring rod 1 is a rod body having a double pipe structure composed of an inner pipe 7 and an outer pipe 8. One of the inner pipe 7 and the outer pipe 8 is right by the speed change mechanism of the speed reducer. The other is rotated counterclockwise such that the other rotates counterclockwise.

At the tip of the stirring rod 1, as shown in FIG. 2, the inner pipe 7 is formed so as to project slightly ahead of the tip of the outer pipe 8, and the tip of the inner pipe 7 is provided with a digging blade. Two are provided. The digging blade 2 is composed of a tip digging blade 4 fixed at the most distal end and a stirring and digging blade 5 fixed above the tip digging blade 4, and the tip digging blade 4 includes an inner pipe 7. It is composed of a pair of left and right digging blades 4a and 4b that are symmetrically provided about the center.
A plurality of excavating bits 10 are provided below the right excavating blades 4a and 4b. The left and right excavating blades 4a, 4b are each formed to be inclined at a predetermined angle, and the cutting edges of the excavating bits 10, 10 ... Are attached so as to enter the ground at a predetermined angle. In this case, the inclination angles of the left and right excavating blades 4a and 4b are preferably 80 to 95 °. A solidified material discharge port 9 is formed at the most distal end of the inner tube 7 so that a cement-based or lime-based powder or liquid solidified material is discharged.

Similarly, the agitating and excavating blade 5 also comprises a pair of a left agitating and excavating blade 5a and a right agitating and excavating blade 5b, which are symmetrically provided about the inner pipe 7. The agitating digging blades 5a, 5b are the digging blades 4a,
It is fixed at a position shifted by 90 ° in a plane with respect to the mounting position of 4b. Further, a plurality of excavation bits 10 are provided below both the agitating and excavating blades 5a and 5b, and the excavation diameter of the agitating and excavating blade 5 is substantially the same as that of the agitating blade 3A described later. Further, the left and right agitating excavating blades 5a, 5b are also formed to be inclined by a predetermined angle, as in the case of the tip excavating blade 4, and the tip of the tip excavating bits 10, 10 ... With respect to the ground. It is attached so that it can enter at a predetermined angle. In this case, the left / right stirring / excavating blades 5a, 5b have an inclination angle of 40-
It is desirable to set it to 50 °.

The tip digging blade 4 and the agitating digging blade 5 are spirally connected by a continuous blade 6 connecting them. As shown in FIG. 4, the continuous blade 6 has a left side continuous blade 6a for spirally connecting the upper end side of the left side excavating blade 4a and the lower end side of the left stirring and excavating blade 5a, and the right side excavating blade 4b. And a right-side continuous blade 6b that continuously connects the upper end side of the right-side stirring and lower-end side of the right-side stirring excavating blade 5b in a spiral shape. The portion which is agitated by the combined use excavating blade 5 and is located outside the excavating blade 4 is first excavated by the agitating and combined excavating blade 5. In this case, the inclination angle of the continuous blade 6 is preferably 20 to 30 °.

On the other hand, stirring blades 3A to 3C are provided in the vicinity of the tip of the outer tube 8 in a vertical arrangement in three stages in the illustrated example. Each of these stirring blades 3A to 3C is composed of a pair of stirring blades 3a and a pair of stirring blades 3b that are symmetrically provided around the outer tube 8. An excavation bit 10 is provided at an appropriate position above the stirring blades 3a and 3b of the stirring blades 3B and 3C, and is used for excavation when the stirring rod 1 is pulled down. Further, at least one of the stirring blades 3A to 3C, in the illustrated example, the stirring blade 3C is replaced with the other stirring blades 3A, 3C.
It is shorter than B. By doing so, it is possible to improve the stirring performance on the shaft center side and reduce the resistance when the stirring rod 1 is pulled up. Also,
The stirring blades 3a, 3b are formed to be inclined by a predetermined angle, and are attached so that the cutting edge of the excavating bit 10 enters the ground at a predetermined angle. in this case,
The inclination angles of the stirring blades 3a and 3b are 25 to 35.
It is desirable to set to °. In addition, the respective stirring blades 3A to 3C are
They are arranged so as to be shifted by 90 ° when viewed two-dimensionally. Although the stirring blades are arranged in three stages in this example, they may be arranged in one stage, or may be arranged in four or more stages. Also, the number of stirring blades formed in each stage may be, for example, 3 blades or 4 blades. The stirring blade 3
The drill bit 10 attached to a, 3b can be omitted.

In the present embodiment, in order to shear the excavated soil also in the vertical direction, a plurality of vertical shearing auxiliary blades 11 are provided vertically to the stirring blade 3A. This vertical shearing auxiliary blade 11
Is preferably formed as long as possible in a range where it does not come into contact with the lower stirring and excavating blade 5 so as to secure a large shearing surface. Generally, it is desirable that the length of the vertical shearing auxiliary blade 11 is at least 10 cm or more, preferably 20 cm or more. Further, as shown in FIG. 5, it is desirable that the end face 11a on the rotational direction side of the vertical shearing auxiliary blade 11 is formed into a blade shape to reduce shearing resistance. Further, as shown in FIG. 3, it is desirable that the longitudinal shearing auxiliary blades 11 are arranged in a plane with the orientation direction being the tangential direction. If it is arranged so as to be inclined with respect to the tangential direction, when shearing the excavated soil, a component force is applied to the stirring rod 1 in the centripetal direction or the centrifugal direction, which causes axial bending, so it is arranged in the tangential direction. As a result, the excavated soil can be effectively cut without receiving the component force.

In this embodiment, the vertical shearing auxiliary blade 11 is provided only for the lowermost stirring blade 3A, but it may be provided for the other stirring blades 3B, 3C. Further, it may be provided for a stirring blade arbitrarily selected from all the stirring blades 3A to 3C.

The double-tube type stirring blade structure in which the inner tube 7 and the outer tube 8 rotate in the forward and reverse directions respectively has been described above, but the present invention has described the single-tube rod type stirring without a forward-reverse rotation mechanism. The same can be applied to the wings.

Next, the improvement procedure by the above-mentioned ground improvement device will be described with reference to FIG. 6. As shown in FIG. 6 (A), after setting the excavating blade 2 at the tip of the stirring rod 1 at a predetermined position, the power swivel is set. The stirring rod 1 is penetrated by driving 20 and, as shown in FIG. 6 (B), it is dug up to the start position of the improvement section. In addition, the penetration up to this point is performed without discharging the solidified material from the solidified material discharge port 9 at the tip.

Next, while the cement-based or lime-based liquid or powder solidification material is being discharged from the improvement start position through the discharge port 9 of the inner pipe 7, the ground excavation blade 2 is used to excavate the ground and also serves as a stirrer. The excavated soil and the solidified material are stirred and mixed by the excavating blade 5 and the stirring blades 3A to 3C. In this case, the descending speed of the stirring rod 1 is 0.3 to 1.0 m / min.
It is good to make it moderate and penetrate slowly.

When the stirring rod 1 reaches the supporting ground,
After reversing the rotation directions of the inner pipe 7 and the outer pipe 8, the stirring rod 1 is pulled upward. Also when pulling up, the excavating soil 5 and the stirring blade 3 are used to slowly pull up while stirring and mixing the excavated soil and the solidified material. The number of revolutions of the stirring blade 3 and the excavating blade 2 varies depending on the soil condition of the soil to be improved, but the number of blade cutting per 1 m is 300 to 60.
It is desirable to set it to 0 times. Here, the number of blade cutting is the number of revolutions per 1 m of the improved portion of the stirring blade 3 and the excavating blade 2, and is a value obtained by summing all the rotational speeds of the stirring blade 3 and the excavating blade 2 when descending and ascending. Say.

[0028]

As described above in detail, according to the present invention, the stirring blade structure capable of uniformly stirring and mixing the excavated soil and the solidifying material can be provided by simply changing the conventional stirring blade structure. As a result, it becomes possible to produce a good improved product with no variation in the consolidation strength.

[Brief description of drawings]

FIG. 1 is an overall side view of a ground improvement device.

FIG. 2 is an enlarged view of a tip portion of a stirring rod.

FIG. 3 is a view taken along line III-III in FIG. 2;

4 is a view taken along the line IV-IV of FIG.

FIG. 5 is a partial perspective view showing another example of a stirring blade for vertical shearing.

FIG. 6 is a process sequence diagram showing a ground improvement procedure.

FIG. 7 is a schematic view of a conventional stirring blade structure.

FIG. 8 is a schematic view of a conventional stirring blade structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rod, 2 ... Drilling blade, 3 ... Stirring blade, 4 ... Tip drilling blade, 5 ... Stirring blade, 6 ... Continuous blade, 7 ... Inner pipe, 8 ...
Outer pipe, 9 ... Solidifying material discharge port, 10 ... Drilling bit, 11 ... Auxiliary blade for vertical shearing

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norihiro Kojo 4-35-3, 9dan-kita, Chiyoda-ku, Tokyo Inside LITE Industry Co., Ltd. (72) 4--2-9, 9dan, Mita Naito, Chiyoda-ku, Tokyo No. 35 Light Industry Co., Ltd.

Claims (6)

[Claims] 1. A ground improvement apparatus comprising a stirring blade extending radially in a forward portion of a stirring rod, wherein at least one of the stirring blades has a vertical shearing auxiliary extending substantially along the axial direction of the rod. Ground improvement device characterized by having wings attached. 2. A stirring blade to which the vertical shearing auxiliary blade is attached,
The ground improvement device according to claim 1, which is a lowermost stirring blade or a combination including the lowermost stirring blade. 3. The ground improvement device according to claim 1, wherein the end face of the vertical shearing auxiliary blade has a blade shape. 4. The ground improvement device according to claim 1, wherein a planar orientation direction of the vertical shearing auxiliary blade is a tangential direction. 5. The ground improvement device according to claim 1, wherein the stirring rod is a rod body having a double pipe structure composed of an inner pipe and an outer pipe, and the inner pipe and the outer pipe are rotated in directions opposite to each other. 6. A digging blade is provided at the tip of the inner pipe, a plurality of stirring blades are provided at the tip of the outer pipe located on the upper side of the digging blade in a step in the rod axial direction, and the digging blade is provided. The ground according to claim 5, comprising a tip drilling blade and a stirring and combined drilling blade located on the upper side thereof, and a plurality of vertical shearing auxiliary blades directed toward the tip end side in the rod axial direction are provided on the lowermost stirring blade. Improved device.