JPH018587Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a method for creating soil improvement pillars, etc., by digging holes in the ground, injecting hardening agents such as cement milk, quicklime, and slaked lime, soil stabilizers, etc. while stirring, and converting it into soil and sand. The present invention relates to a ground improvement method that mixes, stirs, and creates soil improvement pillars, walls, blocks, etc. in the ground using soil mortar, etc., and relates to a device used to create the soil improvement pillars, etc.

Conventionally, when constructing soil improvement pillars underground in the ground improvement method, a hole stirring device 1' such as an auger with stirring blades is used as shown in Figure 1, and this is carried out using a crawler crane or similar device. It is mounted on a construction machine, drills a hole in the ground, injects cement milk, etc. while stirring, and creates improved pillars such as soil mortar pillars underground. However, in this case, the improved pillars 20' to be constructed have a uniform diameter in the depth direction of the ground as shown in Figure 2, and therefore, for example, as shown in Figure 3, the stratum A in the ground that requires improvement is If it is located several meters below the ground surface, it is necessary to drill a hole in the upper stratum B, which does not require improvement, with the same cross-sectional area as stratum A, which requires improvement, and as shown in Figure 4, the ground must be improved. The degree of improvement and improved column diameter (improvement range) are determined depending on changes in the properties and strength of the soil that makes up the ground, such as the existence of strata A and strata A' and A' that require some degree of improvement.
Even when it is desired to change the column diameter, it can only be constructed with a uniform column diameter over the entire length in the depth direction, which is wasteful and disadvantageous.

In view of the above, the present invention is based on the soil quality depending on the depth.
It is designed to easily and reliably construct soil improvement pillars that can efficiently, economically, and uniformly improve soils with different strengths, etc.
Its feature is that the lower part of the auger shaft, whose inner hole serves as a pressure feed hole for hardening agents such as cement milk, and other injection agents, has an enlarged blade that opens and closes at right angles to the axial direction depending on the forward and reverse rotation of the auger shaft. A plurality of enlarged blade type stirring devices consisting of the above-mentioned auger shaft are provided at required intervals in the axial direction, and one or more types of stirring parts such as stirring blades and screw blades are installed at least above and below the auger shaft. It is found in equipment for creating soil improvement pillars etc. that protrudes between stirring equipment.

Next, embodiments of the present invention will be described based on the drawings.
In Figures 5 to 12, reference numeral 1 denotes an auger shaft whose inner hole serves as a pressure feed hole 2 for hardening agents such as cement milk and quicklime, soil stabilizers, and other injection agents, and is equipped with a drive motor and a speed reduction mechanism. upper drive part 3
The auger shaft 1 is connected to the auger shaft 1, and its inner hole is connected to a pump for supplying hardening agent, etc., and a discharge port 4 for the hardening agent, etc. and a drilling head 5 are provided at the tip (lower end) of the auger shaft 1. Reference numeral 6 denotes a plurality of expanding blade type stirring devices arranged at required intervals in the axial direction, that is, in the vertical direction, at least in the lower part of the auger shaft 1 near the excavation head 5, and each of these stirring devices 6 is shown in FIGS. As shown in an enlarged view in Fig. 8, the enlarged blade opens and closes by rotating around the support pin 7 when rotating in the forward or reverse direction. It is equipped with enlarged blades 8 having a diameter (dashed line in the figure) at 180 degrees opposite positions, 9 is a support part of the enlarged blade 8, 1
0 is a stopper when the expanding blade 8 is expanded. The expanding blade 8 is set so that its tip protrudes from the support base 9 for stirring even when the diameter is reduced, and the protrusion length when expanding and contracting depends on the size of the expanding blade 8. different. In addition, the expanding blade type stirring device 6 is arranged such that the directions of the expanding blades 8 of the vertically adjacent stirring devices 6, 6 are displaced by a required angle in the circumferential direction from each other. It is desirable for the effect, and the displacement angle is set to, for example, 90 degrees (angle) so that the enlarged blades 8, 8 of the vertically adjacent stirring devices 6, 6 are orthogonal in the expanded state, as shown in the figure. , 90° to 30° (angular), and can also be installed by sequentially displacing the stirring device 6 at an appropriate angle upward from the lowest stirring device 6 near the excavation head 5.

Further, the auger shaft 1 is provided with one or more types of stirring parts such as stirring blades 11, 12 and screw blades 13 other than the enlarged blade type stirring device 6, at least the upper and lower stirring devices 6, 6. 5 (Fig. 6) and 9.
As shown in FIGS. 11 to 11, it is preferable to arrange the above-mentioned stirring parts both between the upper and lower stirring devices 6 and 6 and above the group of stirring devices. As the stirring part, one or more kinds of rod-shaped stirring blades 11, arc-shaped stirring blades 12, screw blades 13, etc. can be appropriately combined. FIG. 10 shows the case where only the rod-shaped stirring blades 11 are installed, and FIG. 11 shows the case where the rod-shaped stirring blades 11 and the arc-shaped stirring blades 12 are installed. . In any of these cases, it is preferable that the rotational diameter of the stirring piece is set to be approximately the same as when the expanding blade 8 of the stirring device 6 is closed and the diameter is reduced.

The device of the present invention is configured as described above,
To explain the construction of soil improvement pillars in the ground as shown in FIG. 3 using this device, first, as shown in FIG. A hole is drilled in the stratum B that does not require improvement while reducing the diameter of the hole. When the part of the stirring device 6 reaches the stratum A that requires improvement, the auger shaft 1 is rotated in the opposite direction to the above, and the enlarged blade 8 of the stirring device 6 is expanded as shown in FIG. While expanding the diameter,
Cement milk, hardening agents such as slaked lime, soil stabilizers, and other injection agents are pumped through the auger shaft 1 and are discharged from the tip, and the excavation is carried out while mixing and stirring these with the ground soil. When the drilling of a predetermined length (depth) and mixing and stirring are completed, the apparatus of the present invention is pulled up. In addition, in stratum B that does not require improvement, the stirring device 6 can be reduced in diameter and pulled up. The first layer has a small diameter in stratum B, which has a large area and does not require improvement.
A ground improvement pillar 20 such as a soil mortar pillar as shown in FIG. 2 or 13 will be constructed. Further, depending on the spacing between the stirring devices, it is also possible to create an improved column having enlarged diameter portions and small diameter portions alternately, as shown in FIG. 13, without moving the auger shaft up and down that much. Note that the auger shaft 1 is equipped with stirring blades 11 and 12 that are separate from the stirring device 6, and screw blades 1.
Since the stirring member No. 3 is provided, the above-mentioned mixing and stirring is further assisted and carried out effectively.

In the above, while the enlarged blade type stirring device 6 is kept in the reduced diameter state, a hole is dug to a predetermined depth in the stratum A that requires improvement, and when the device of the present invention is pulled up, the agitation is carried out in the portion of the stratum A that requires improvement. Mixing and agitation may be carried out while enlarging the hole diameter by setting the device 6 in an expanded state, thereby making it possible to create a ground improvement column similar to that described above.

In addition, when construction is carried out on the ground that includes stratum A' that requires improvement to some extent and stratum A that requires improvement, as shown in Fig. 4, in the stratum A that requires improvement, the expanding blade 8 of the expanding blade stirring device 6 is expanded in the same way as above. For strata that require improvement to some extent, the diameter of the stirring device 6 may be reduced to perform mixing and agitation, and as shown in FIG. In the stratum A' which requires some degree of improvement, a soil improvement pillar 20 made of soil mortar or the like having a diameter slightly smaller than that described above can be constructed. The degree of change in the column diameter due to the diameter reduction of the expanding blade 8 is easily determined by the degree of diameter reduction due to the size of the expanding blade 8 of the stirring device 6, that is, the protruding length of the expanding blade 8 of the stirring device 6 when the diameter is contracted. In particular, the protruding lengths of the enlarged blades 8 of the vertically adjacent stirring devices 6 at the time of diameter reduction can also be set to be different. The soil improvement pillars constructed in this way have a large diameter in the stratum A that requires improvement, and have a slightly smaller diameter in the stratum A' that requires some improvement.

Once one unit of soil improvement pillars 20 has been constructed as described above, the next one unit of soil improvement pillars is constructed in the same manner as above, but in this case, each soil improvement pillar is separated in a scattered manner. In addition to construction, they can be constructed in parallel at slight intervals as shown in Figure 12, or they can be partially wrapped, and in this way, ground improvement pillars, walls, blocks, etc. can be created as desired. can.

As mentioned above, since the production device of the present invention is formed by disposing a plurality of enlarged blade type stirring devices vertically at the required intervals below the auger shaft,
The diameter of the soil improvement column, that is, the improvement range, can be changed in the depth direction in accordance with the strata structure such as the properties and strength of the soil constituting the ground, making it easy to create an improved column with an optimal shape. In particular, the expanded blade type stirring device is provided in multiple stages and can simultaneously stir a wide area, and not only does the expanded blade have an excellent stirring effect, but it also has stirring parts such as stirring blades and screw blades that are separate from the stirring device. Since one or more of these are provided at least at the locations between the stirring devices, the stirring effect is further enhanced, and the hardening agent, soil stabilizer, and ground soil can be uniformly mixed evenly, resulting in a high-quality product. It is possible to obtain a soil improvement pillar made of soil mortar or the like, and together with the shape according to the above-mentioned strata, it is possible to exhibit an extremely excellent ground improvement effect. In addition, it is economical and efficient because the strata that require improvement can be improved to a greater extent than others by drilling and stirring in one step, and even when multiple soil improvement pillars are created by wrapping, etc. is large, and the construction period can be significantly shortened.
In addition, in geological formations that do not require improvement, the enlarged blade type stirring device is reduced in diameter to dig holes and stir, so there is no waste in the digging holes and stirring action, and construction workability can be improved.

In particular, when a plurality of enlarged blade type stirring devices are arranged at intervals in the axial direction, when the diameter of the enlarged blades is reduced and the digging blade is provided at the lower end of the auger shaft,
Since the stirring action of the compacted stirring device is lower than that when the diameter is expanded, it becomes a resistance to the digging action and makes it difficult to dig, but in the case of the present invention, the stirring device placed between multiple stirring devices Due to the stirring action of one to several kinds of stirring pieces, the hole digging action by reducing the diameter of the enlarged blade is also improved despite the provision of a plurality of stirring devices.

Furthermore, depending on the size of the enlarged blade, stirring can be performed even when the diameter of the stirring device is reduced, so it is possible to obtain improved columns with two different diameters when the diameter is expanded and when the diameter is reduced.
Further, the diameter of the stirring device can be easily expanded or decreased by rotating the auger shaft in the forward or reverse direction, so the mechanism is simple and the operation is easy.

[Brief explanation of the drawing]

Fig. 1 is a front view illustrating a conventional device, Fig. 2 is a cross-sectional view showing a soil improvement pillar created by the conventional device, Figs. 3 and 4 are cross-sectional views illustrating the stratum structure of the ground, and Fig. 5 Figures 5 to 12 show examples of the present invention, and Figures 5 and 6 are front views of the enlarged blade type stirring device during construction with its diameter reduced and expanded;
Fig. 7 is an enlarged front view of the enlarged blade type stirring device portion, Fig. 8 is a sectional view taken along the line from the front figure, Figs. 9 to 11 are front views showing other embodiments, and Figs. 12 to 11.
FIG. 14 is a cross-sectional view showing soil improvement columns constructed by the apparatus of the present invention. 1... Auger shaft, 2... Pressure hole, 6... Expanded blade type stirring device, 8... Expanded blade, 11, 12... Stirring blade, 13... Screw blade, A... Geological stratum requiring improvement, A'... Geological strata that require some degree of improvement.
B...Soil layer that does not require improvement, 20...Soil improvement pillar.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. An enlarged blade that opens and closes at right angles to the shaft direction by rotating forward and backward, at the bottom of the auger shaft whose inner hole serves as a pressure feed hole for hardening agents such as cement milk and other injection agents. A plurality of enlarged blade type stirring devices equipped with the above-mentioned auger shaft are provided at required intervals in the axial direction, and one or more types of stirring parts such as stirring blades and screw blades are installed at least above and below the auger shaft. A device for creating soil improvement columns, etc., which is protruded between stirring devices. 2. The plurality of expanding blade type stirring devices are provided in such a manner that the expanding directions of the expanding blades of the vertically adjacent stirring devices are displaced by a required angle in the circumferential direction from each other. Equipment for creating soil improvement pillars, etc. as described in Section 1.