JP2881481B2 - Deep mixing machine and pile cap method using the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deep mixing apparatus used in a deep mixing processing method, which is a kind of ground improvement method, and a pile cap method performed by the deep mixing processing method. .

2. Description of the Related Art As shown in FIG.
A stirring blade 3 is installed at the lower end of a rotating blade shaft 2 that is supported vertically and rotatably supported by an earth auger 1 on the ground, and the rotating blade shaft 2 uses a slurry 4 such as a ground stabilizer from the lower end thereof. It has a pipe structure capable of discharging, and is configured to mix the earth and sand and the slurry 4 which have been rotationally excavated by the stirring blade 3 at an original position.

Therefore, the improved soil pile 5 constructed by the above-described deep mixing machine was a uniform-diameter pile whose diameter did not change from the upper end to the lower end as shown in FIGS.

Problems to be Solved by the Present Invention I) Since the improved soil pile 5 constructed by the conventional deep mixing machine is a uniform diameter pile whose diameter does not change, its arrangement pitch is large and sparse (therefore, the ground improvement rate). When the embankment 6 is placed on the improved soil piles 5..., The embankment 6 gradually sinks between the piles as an effect of aging, and there is a drawback that uneven settlement occurs on the surface of the embankment 6. In the figure, reference numeral 7 indicates a support layer ground.

II) Conventionally, as a countermeasure to solve the disadvantage of the above-mentioned uneven settlement, as shown in Figs. 7A and 7B, for example, as shown in Figs. Alternatively, as shown in FIG. 8, many construction methods for horizontally laying so-called geotextiles 8 such as fibers, nets, sheets, etc., on the head of the improved soil pile 5 are being implemented. However, in the former construction method, the number of the improved soil piles 5 is increased and the improvement rate of the ground is drastically increased, so that the number of construction steps is increased, the construction period is prolonged, and the cost is increased. The latter construction method also has a drawback that the cost increases as much as the geotextile 8 is consumed and the laying process increases.

III) Conventionally, as a method of constructing road embankments with little settlement in areas where there are many high organic
Concrete pile and pine pile 9
Reinforced concrete floor slab as a head tie to the pile head
A method of constructing 10 and placing the embankment 6 thereon, or a method of constructing a concrete cap 11 on the head of a pine pile 9 and placing the embankment 6 thereon as shown in FIG. 10, or as shown in FIG. In many cases, a connection reinforcing bar 12 and a geotextile 8 are constructed on a pile head, and an embankment 6 is placed thereon.

Also, in the case of offshore construction using the above-mentioned conventional deep mixing machine (Fig. 5), if a continuous wall-shaped improved soil pile is required, two adjacent piles as shown in Figs. Pile cap 1 overlapping the head of improved soil pile 5,5
A construction method that implements 3 and expects the same effect as the pile cap method shown in Fig. 10 has also been implemented. However, in the case of this construction method, one improved soil pile 5 and two pile caps 13 on both sides constitute one set, and in other words, three steps are required, so much work is required for the construction. . Moreover, since the improved earth pile 5 and the pile cap 13 are joined, the reliability of the joint between them is not perfect.

The above problems are the problems to be solved by the present invention.

Means for Solving the Problems (First to Third Inventions) As means for solving the above-described problems of the prior art, a deep mixing machine according to the present invention is shown in FIGS.
As shown in FIGS. 3A and 3B, the lower stirring blade 3 is installed at the tip of the rotating blade shaft 2 having a pipe structure capable of discharging the slurry of the ground stabilizer, and the upper stirring blade is positioned near the ground surface. Wings 20 were installed. The lower stirring blade 3 has a length corresponding to the pile portion diameter d, and the upper stirring blade 20 has a length corresponding to the cap portion diameter D. At least the lower stirring blade 3 (if necessary, the upper stirring blade Two
A feature is that a downward or horizontal slurry discharge port is provided in the vicinity of (0) (FIG. 1).

Moreover, the upper stirring blades 20 of the deep mixing apparatus of the present invention are:
Its position is variable in the vertical direction along the rotary blade axis 2 (FIG. 2), and the upper stirring blade 20 refracts in a specific rotational direction but has one straight rod shape in the reverse direction. (A in FIG. 3, FIG. 3A)
B) and are also features.

Operation When the ground 24 is mixed by this deep mixing machine, the pile portion 25 and the cap portion 23 can be constructed in one step (FIGS. 1 and 4A and 4B).

At the time of the rotary excavation of the ground 24 by the large-diameter upper stirring blades 20, since the ground 24 has already been rotary-excavated and mixed by the small-diameter lower stirring blades 3 in a range corresponding to the pile diameter d, and in general, the soft ground In the surface layer portion, the strength of the ground is weak and the overburden pressure is small, so the excavation resistance torque does not become so large, smooth rotation excavation by the upper stirring blade 20 can be performed, and from the position of the upper stirring blade 20 Good mixing can be achieved without the need to discharge the stabilizer slurry.

The upper stirring blade 20 whose position is variable in the vertical direction along the rotary blade axis 2 can freely cope with the case where the improved depth H of the cap portion 23 varies depending on the location.

Since the one-piece type enlarged blade piece 22 has a configuration in which the substantial length of the upper stirring blade 20 is different between forward rotation and reverse rotation, management can be made compact by folding the expanded blade piece 22 when storing on the ground.

(Fourth invention) The pile cap method using the deep mixing machine according to the fourth invention is a rotating blade having a pipe structure capable of discharging a ground stabilizer slurry, as shown in the embodiment in Figs. 4A and 4B. The lower stirring blade 3 is installed at the tip of the shaft 2 and the upper stirring blade 20 is installed at a position near the ground surface. The lower stirring blade 3 has a length corresponding to the pile diameter d. Has a length corresponding to the diameter D of the cap portion, and a depth mixing machine in which a slurry discharge port is provided at least in the vicinity of the lower stirring blade 3 (the upper stirring blade 20 if necessary) to pierce the ground 24 with a depth. Drill in the direction. First, the ground 24 is excavated by the lower stirring blade 3 and mixed with the ground stabilizer slurry 4 discharged downward or sideways from the tip of the rotary blade shaft 2 to form a pile portion 25; At the stage when the pile portion 25 is formed to a predetermined depth in the ground, the upper stirring blade 20 is used to excavate the ground surface portion of the ground 24 to a predetermined depth and, if necessary (3.
In the case where the amount of the slurry is insufficient, the step of discharging the ground stabilizer slurry 21 and performing the mixing process to form the upper cap portion 23 is performed.

Operation The lower stirring blade 3 first performs rotary excavation, and the subsequent upper stirring blade 20 again performs rotary excavation on the ground surface portion of the ground 24 mixed with the slurry 4 and discharges the slurry 21 as necessary. Since the mixing process is performed to form the cap portion 23, the pile portion 25 and the cap portion 23 become an integrally improved soil structure, and complete reliability is obtained at the joint.

It has the same effect as increasing the improvement rate of the ground by the large-diameter cap portion 23, and by setting the adjacent cap portion 23 in an insulating relationship (Fig. 4A, B), uneven settlement occurs with a small number of man-hours. Can build no embankment.

Embodiment Next, an embodiment of the present invention shown in FIGS. 1 to 4A and 4B will be described.

The deep mixing processor shown in FIG. 1 is supported vertically downward by an earth auger 1 on the ground, is driven to rotate, and is provided with a lower portion at the tip of a rotary blade shaft 2 having a pipe structure capable of discharging a slurry of a ground stabilizer. The stirring blade 3 is installed, and the ground surface (G
-The upper stirring blade 20 is installed in the vicinity of (L).
The lower stirring blade 3 has a length corresponding to the diameter d of the small diameter pile portion 25 (d is usually about 100 cm to 150 cm), and the upper stirring blade 20 has a diameter D (D is usually 200 cm) of the large diameter cap portion 23.
~ 300cm). A discharge port for the slurry 4 is provided downward from the tip (lower end) of the rotary blade shaft 2 (or laterally from a position substantially at the same level as the lower stirring blade 3). If necessary, the horizontal slurry can be placed at almost the same level as the upper stirring blade 20.
21 outlets may be provided. In this case, supply and stop of the slurries 4 and 21 are controlled by separate systems to the two slurry discharge ports.

The upper stirring blade 20 rotates in the same manner as the rotary blade shaft 2 using, for example, a sliding key as shown in FIG. 2 in addition to fixing the mounting position with respect to the rotary blade shaft 2. The installation position is made variable in the vertical direction along the axis 2, so that the improved depth H of the cap portion 23 (first
It is convenient to carry out the configuration in such a manner that it can cope with the case where the figure differs depending on the place. And also, the upper stirring blade 20
As shown in FIGS. 3A and 3B, it is also convenient to configure and implement a half-folded enlarged blade piece 22 that is rotatably connected by a pin 26 at about a half of the distal end. It is.
Moreover, the connecting portion of the enlarged blade piece 22 by the pin 26 includes:
As shown in FIG. 3B, when the upper stirring blade 20 rotates counterclockwise, a stopper 27 for stopping the enlarged blade piece 22 at one straight rod-like position is provided, and in this state, the large-diameter cap portion 23 is removed. It is configured to be capable of rotating excavation and mixing with the slurry 21. Conversely, as shown in FIG. 3A, when the upper stirring blade 20 rotates clockwise or when the rotation is stopped, the expanded blade piece 22 bends at the position of the pin 26, and the storage is performed in a compact form. It is preferable to implement the configuration in a space-saving manner.

In the construction of the pile cap method carried out by the deep mixing machine having the above-described configuration, as shown in FIG. 1, the earth auger 1 is first installed at a predetermined position on the ground 24, and the ground 24 is Drill vertically downward. At the same time, the slurry 4 of the ground stabilizer is discharged from the tip of the rotating blade shaft 2 and mixed with excavated soil to form a pile portion 25 having a diameter d of improved soil. Thus, the construction of the pile portion 25 by the lower stirring blade 3 is advanced in the depth direction of the ground 24, and when reaching a predetermined depth (for example, the position of the support layer ground 7), the subsequent upper stirring blade 20 reaches the ground surface GL. Then, the ground surface portion of the ground 24 is excavated by rotation in the depth direction, and the mixing process is performed using the slurry 4 discharged from the position of the preceding lower stirring blade 3. However, if the amount of the slurry 4 is insufficient, the slurry 21 is discharged laterally from a position substantially at the same level as the upper stirring blades 20 to sufficiently mix the excavated soil with the slurry 4. The cap portion 23 is formed. The formation of the upper cap portion 23 is performed by first passing through the lower stirring blades 3 and mixing and improving the soil portion by rotary excavation again and mixing with the slurry 21. As a result, the pile portion 25 and the upper cap portion 23 are eventually formed.
Is formed as an improved soil structure that is completely integrated. The pipe portion 25 has a diameter d of 100c according to the length of the lower stirring blade 3.
The depth is about m to 150 cm, and is usually formed as a deep mixing process from the ground surface G / L to a depth reaching the support layer ground 7.
The upper cap portion 23 on the ground surface has a diameter D of about 200 cm to 300 cm and a depth H depending on the length of the upper stirring blade 20.
Is formed as about 2m.

In particular, the construction of this pile cap method is shown in Figs.
As shown in the example, the pile portion 25 is formed so that the upper caps 23 are in contact with or close to each other, and the embankment 6 is placed on the upper cap portion 23 to build a residential land or construct a road.

According to the deep mixing machine and the pile cap method according to the present invention, the formation of the pile portion 25 and the formation of the upper cap portion 23 by the improved soil are performed in one process, so The efficiency of sex is very good. In addition, since the pile portion 25 and the upper cap portion 23 are formed of a completely integrated improved soil, the reliability of the joint is complete and a high quality product can be formed.

In addition, since a large diameter upper cap portion 23 can provide the same support effect as the substantial improvement rate is increased, there is no fear of uneven settlement of the embankment 6 placed thereon, and there is no worry of settlement, and a highly stable residential land. Construction sites and roads can be constructed with high quality and at low cost.

[Brief description of the drawings]

FIG. 1 is an elevational view showing a form of a deep mixing machine according to the present invention and an improved soil constructed by the same, FIG. 2 is a perspective view showing an example of a configuration of an upper stirring blade, and FIG. , B are plan views showing different embodiments of the upper stirring blade, FIGS. 4A and 4B are elevation and plan views partially showing the construction state of the pile cap method, and FIG. 5 is a conventional deep mixing Elevation view showing the processing machine, FIG. 6 is an elevation view showing a construction example of the deep mixing processing machine,
7A and 7B are elevation views and plan views showing different construction examples, FIG. 8 is an elevation view showing still another construction example, FIGS.
Fig. 11 is an elevation view showing an example of construction of a conventional road embankment, etc.
12A and 12B are an elevation view and a plan view showing an example of construction of a continuous wall-shaped improved soil pile by a conventional deep mixing machine. 4,21 Slurry 2, Rotating blade shaft 20 Upper blade shaft 22, Expanded blade piece 24 Ground, 23 Upper cap part 25 Pile part

──────────────────────────────────────────────────続 き Continued on the front page (72) Yoshio Suzuki, Inventor 2-5-1-14 Minamisuna, Koto-ku, Tokyo Inside the Technical Research Institute, Takenaka Corporation (72) Katsumi Shirai 8-2-1-1, Ginza, Chuo-ku, Tokyo No. Takenaka Civil Engineering Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) E02D 3/12 102

Claims (4)

(57) [Claims] 1. A lower stirring blade is installed at the tip of a rotating blade shaft having a pipe structure capable of discharging a slurry of a ground stabilizer, an upper stirring blade is installed at a position near the ground surface, and the lower stirring blade is A depth corresponding to the diameter of the pile portion, the upper stirring blade having a length corresponding to the diameter of the cap portion, and a slurry discharge port provided at least in the vicinity of the lower stirring blade. Mixing machine. 2. The deep mixing processor according to claim 1, wherein the position of the upper stirring blade is variable in the vertical direction along the rotating blade axis. 3. An upper stirring blade is characterized in that the tip of the blade is formed by a single-fold type enlarged blade piece which is bent in a specific rotation direction but becomes one straight bar in the reverse rotation direction. The deep mixing machine according to claim 1 or 2, wherein: 4. A lower stirring blade is installed at the tip of a rotating blade shaft having a tube structure capable of discharging a ground stabilizer slurry, and an upper stirring blade is installed near the ground surface. The blade has a length corresponding to the pile diameter,
The upper stirring blade has a length corresponding to the cap diameter,
The ground is excavated in the depth direction with a deep mixing machine provided with a slurry discharge port at least in the vicinity of the lower stirring blade. B) First, the ground is rotatably excavated with the lower stirring blade and downward from the tip of the rotating blade shaft. Or a step of forming a pile portion by mixing with a slurry of the ground stabilizer discharged laterally; c) forming the pile portion to a predetermined depth in the ground, and using the upper stirring blades to cut the ground surface of the ground. Forming a top cap portion by rotating and excavating to a predetermined depth and discharging a ground stabilizer slurry as required to form an upper cap portion. A pile cap method using a deep mixing machine.