JPH01190818A - Columnar improved body for ground and construction method and construction device thereof - Google Patents

Abstract

PURPOSE:To construct a columnar body having less settlement by foldably providing a claw capable of projecting further outward than the outside diameter of an auger blade to a screw auger, and thereby excavating a hole having enlarged projected parts, and filling it with mixed soil in which a powder solidifying agent is added. CONSTITUTION:While a straight excavating hole C is formed by a screw auger 5, excavated soil P is discharged outside the hole, and then a recessed-part- forming claw 15 (not shown) having been rotatably provided near to the lower side of the auger shaft part is unfolded to form a recessed part D by turning the auger 5. After once the auger 5 has been drawn out from the excavated hole C, a powder solidifying agent Q is mixed with the excavated soil P, and then the auger 5 is again lowered, thereafter the auger 5 is turned in the reverse direction, so that the mixed soil is backfilled inside the excavated hole C. Thus, a columnar improved body having less settlement can be easily constructed.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a columnar improvement body constructed in shallow and intermediate ground using on-site and powder solidification shrines in order to improve and reinforce the ground. The present invention relates to an improved columnar body, a method for creating it, and an enlarging device for creating the same.

(Prior art) As a construction method for creating columnar improved bodies, there has been a so-called slurry construction method, but this construction method requires large construction machinery such as a solidification material supply plant, and also requires a large amount of water. There are problems such as the amount of solidifying material used increases and it overflows from the excavation hole, making it difficult to work.

In order to solve various problems with the slurry construction method, the applicant of the present application conducted excavation and compaction with a screw auger using a powdered solidified material and on-site soil (excavated soil) in Japanese Patent Application No. 60-203849, etc. A method for creating improved columnar bodies has already been proposed.

However, until now, only straight columnar improved bodies have been formed using this method.

(Object of the Invention) The object of the present invention is to provide an improved columnar body that can significantly reduce the amount of settlement of the improved columnar body constructed from on-site (excavated soil) and powder solidified material. That's true. Furthermore, it is another object of the present invention to provide a method for producing the above-mentioned improved columnar body with good work efficiency, and an apparatus used therein.

(Technical Means for Achieving the Object) In order to achieve the above object, the present invention provides a column-shaped improved body created in an excavation hole using a mixed soil of excavated soil and powder solidified material discharged from the excavation hole. , an enlarged overhang extending outward in the radial direction is integrally constructed from the above mixed soil.

It is effective to form the enlarged projecting portions at a plurality of locations spaced apart in the vertical direction, and it is even more effective to form them at the lowest end of the excavation hole.

The method for manufacturing the improved columnar body having the above-mentioned overhanging part is to excavate the ground by rotating a screw auger in the forward direction, discharge the excavated soil upward, and mix the excavated soil with a powdered assimilated material into the excavated hole. In the method for creating a columnar improvement body in which the mixed soil is compacted by backfilling and compacting the mixed soil by reversing the rotation of a screw auger, an enlarged recess for forming an overhang is formed in the excavation hole and expands outward from the diameter of the excavation hole, and the above-mentioned method is used. There is a method of creating it by backfilling the expanded depression with mixed soil.

A more specific method for forming a recess is to scrape the circumferential surface of the excavated hole using a recess forming pawl that rotates integrally with the screw auger. There is a method in which a press-type enlarging device separate from the auger is suspended by a crane or the like, and a plurality of concave-forming pressing pieces of the enlarging device are used to press and expand the peripheral surface of the excavation hole to form a concave portion.

Further, as a device used for the former method of forming a recess, a screw auger is provided with a recess forming pawl that protrudes outward beyond the outer diameter of the auger blade and is foldable.

In addition, as a device used for the latter recess formation method, a plurality of hydraulic cylinders that can be expanded and contracted radially outward are provided on the main body of the enlarging device, which can be freely suspended by a crane, etc., and a plurality of partially cylindrical cylinders are provided around the main body. The pressing pieces for forming a recess are arranged on the same circumference, each pressing piece is connected to each cylinder, and each pressing piece can be freely expanded radially outward by extension of the cylinder.

(Function) Since an overhang is formed that extends outward in the radial direction, the amount of settlement in response to so-called overload is reduced, making it more effective in improving the hardness of soft ground.

Since it uses on-site soil (excavated soil) and solidifies it with a powder solidifying agent, it is easier to work with and can save costs compared to the slurry method.

(Example) Fig. 1 is a longitudinal cross-sectional view of a column-shaped improved body, in which a column part A is constructed of a mixed soil of excavated soil (on-site) and powdered solidified material, and there are spaces in the column part in the vertical direction. Two enlarged protruding parts B are integrally formed with the same mixed soil as the pillar part. The powder solidifying material is a cement-based solidifying material whose main materials are plaster, blast furnace slag, and ordinary Portland cement, to which a halogen compound or sulfate is added as a hardening accelerator, if necessary, and mixed well.

That is, this solidifying material has a mixing ratio of the main materials, plaster, blast furnace slag, and ordinary Portland cement, of 15 to 60 (by weight) plaster, 20 to 60 (by weight) blast furnace slag, and 15 to 50 ordinary portland cement. (weight%)
It is made by pulverizing them so that the specific surface area is 4500c//g or less, or by adding 5 (wt%) or less of a hardening accelerator to them and pulverizing and blending them. and has hydraulic properties.

Figures 2 to 7 show the method of creating the columnar improved body of Figure 1 in order of process, Figure 14 shows the screw auger device used in the above creation method, and Figure 15 shows the entire creation device. . First, the entire construction apparatus will be explained with reference to FIG. 15. A rotary drive device 3 is supported by the leader 2 of the traveling work vehicle 1 so as to be movable in the vertical direction, and the upper end 6a of the shaft portion 6 of the screw auger 5 is attached to the drive device 3. The screw auger 5 is rotationally driven by the drive device 3. A swivel portion 7 for oil pressure supply is fitted into the shaft portion 6.
The branch 7a portion thereof abuts against, for example, the leader 2 portion, thereby preventing rotation.

A hydraulic hose 10 is connected to the swivel portion 7, and although not shown, the hydraulic hose 10 is connected to a hydraulic system of the traveling work vehicle 1.

In FIG. 14, a claw attachment cylindrical shaft portion 11 is detachably connected to the middle of the lower side of the auger shaft portion 6.
The cylindrical shaft portion 11 is provided with a recess forming pawl 15 and a double-acting hydraulic cylinder 17 for moving the pawl 15. The pawl 15 is formed in the shape of a "<", and its central portion is rotatably supported by the cylindrical shaft portion 11 by a pin 16, and can be freely changed between the use position shown by the solid line and the storage position shown by the imaginary line. It becomes. In the use position indicated by the solid line, the pawl 15 is perpendicular to the cylinder shaft portion 11 and protrudes radially outward beyond the outer diameter of the auger blade 19. On the other hand, at the storage position indicated by the imaginary line, it is folded in a posture parallel to the cylinder shaft portion 11 and is housed inside the outer diameter of the auger blade.

The end of the claw 15 inside the cylindrical shaft is pivotally connected to the rod of the hydraulic cylinder 17, and can be switched between a use position and a storage position by the expansion and contraction of the hydraulic cylinder 17. For example, when the hydraulic cylinder 17 is extended, it is switched to the use position, and when it is contracted, it is switched to the storage position. The hydraulic cylinder 17 is connected to the hydraulic hose 10 via a hydraulic hose (not shown) within the shaft portion 6 and the swivel portion 7 .

Using a screw auger device having claws 15 as described above, a columnar improved body is constructed as shown in FIGS. 2 to 7. That is: (1) By rotating the auger 5 forward in the Xi force direction with the claw 15 in the storage position as shown in FIG. 2, a straight excavation hole C is formed and the excavated soil P is discharged.

(2) As shown in FIG. 3, the claws 15 are expanded to the use position, and the auger 5 is rotated forward in the X1 direction while appropriately moving up and down to form a recess.

(4> In FIG. 4, when the recess is formed, the claw 15 is stored in the storage position and the auger 5 is raised.

(5) As shown in FIG. 5, spread the claw 15 again to the use position at an appropriate position, rotate it forward in the X1 direction and move it up and down to form a recess, close the claw 15, and open the auger 5. Remove it once.

(6) As shown in Fig. 6, mix the powder fixing material Q with the excavated soil (discharged soil) P, lower the auger 5 again, and reverse it in the X2 direction to fill the mixed soil back into the excavated hole C. .

(7) As shown in Fig. 7, the auger 5 is rotated in the opposite direction to gradually raise the mixed soil while compacting it, thereby creating an improved body of mixed soil upward.

FIGS. 8 to 13 show another manufacturing method using the apparatus shown in FIG. 14, in which the entire process is performed without removing the screw auger 5. That is: (1) By rotating the auger 5 forward in the X1 direction with the claw 15 housed as shown in FIG. 8, a straight excavated hole C is formed and the excavated soil P is discharged.

(2) Expand the claws 15 to the use position as shown in Figure 9, and
A concave portion is formed by appropriately moving it up and down while rotating it in the normal direction.

(4) In Fig. 10, store the claw 15 with the auger 5 inserted, mix the powder solidification material Q with the excavated soil P, and pour the mixed soil into the excavated hole C while rotating the auger 5 in the opposite direction in the X2 direction. backfill.

(5> As shown in Fig. 11, the auger 5 is reversely rotated in the X2 direction to gradually raise the mixed soil while compacting it, thereby creating an improved body of mixed soil from the lower recess to the upper part.

(6) As shown in FIG. 12, the claw 15 is opened again to the use position and the auger 5 is rotated forward in the X1 direction to form the upper recess.

(7) After forming the upper concave part, re-open the claw 1 as shown in Figure 13.
5 is housed, the X2 is rotated in reverse, and the mixed surface is backfilled and compacted.

(Another Example) FIG. 16 shows another example of the improved columnar body, and is an example in which a projecting portion B is formed at the lowermost end.

FIG. 23 shows a construction apparatus suitable for constructing the improved body of FIG. 16. In this FIG. 23, the screw auger 5 is a crane 2 of a small truck auger vehicle 20.
A press-type enlarging device 23, which is separate from the auger 5, is suspended from the crane section 21 so as to be movable in the vertical direction. The screw auger 5 is rotated by receiving rotational power from the auger wheel 20, and is also moved in the vertical direction by the vertical swinging and expansion/contraction operations of the crane 21.

FIG. 24 shows a horizontal sectional view of the press-type enlarging device 23 in FIG. 23, and in this FIG.
5, a partially cylindrical (quadrant) pressing piece 26 is positioned on the same circumference, and the blade body 25 is equipped with four hydraulic cylinders 29 facing outward in the radial direction. There is. The four hydraulic cylinders 29 are divided into two upper and lower stages, and are arranged facing in all directions so as to face the respective pressing pieces 26, and the rod portions 29a are connected to the corresponding pressing pieces 26, respectively. There is. That is, each cylinder 2
9 is expanded, each pressing piece 26 is moved radially outward as shown by the imaginary line in FIG.

In FIG. 25, auxiliary guide rods 30 are fixed to the upper and lower ends of each pressing piece 26, and each auxiliary guide rod 30 is guided by a guide boss 31. Each cylinder 29 is connected to the hydraulic system of the auger wheel 20 via a hydraulic hose 33, as shown in FIG.

17 to 22 show a creation method using the creation device and enlarging device 23 shown in FIG. 23.

That is: (1) As shown in FIG. 17, the screw auger 5 is rotated forward in the X1 direction to form a straight excavation hole C, the excavated soil P is discharged, and the auger 5 is pulled out.

(2) Insert the expanding device 23 in a contracted state to the bottom of the excavation hole C as shown in Fig. 18, and expand the pressing piece 26 radially outward by supplying hydraulic pressure as shown in Fig. 19. (move), thereby forming a recess. By pressurizing the side of the drill hole C, a recess is formed.
The strength of the side wall surface can be increased. Further, when there are soft parts and hard parts on the surrounding surface of the excavation hole C, the expanding device 23 expands to be biased towards the soft part, so that a recess adapted to the softness of the ground can be formed.

(3) As shown in FIGS. 20 and 21, a recess is formed on the upper side in the same manner as described above, and the enlarging device 23 is pulled up.

(4) Then, as shown in FIG. 22, the auger 5 is inserted again and rotated in the opposite direction in the X2 direction to backfill and compact the mixed soil of excavated soil and powdered solidified oil.

After forming the borehole C in Fig. 17 and before inserting the enlarging device 23 in Fig. 18, a small amount of powder solidified material is put into the borehole to prevent the circumferential surface of the borehole C from collapsing due to the rotation of the auger. You can also harden it like this.

Further, in FIG. 23, each hydraulic cylinder of the enlarging device 23 can be connected to the hydraulic system of the track auger vehicle 20 via a pressure intensifier 35.

(Effects of the Invention) Since the present invention is configured as described above, it has the following advantages.

(1) Since the overhanging part B that extends outward in the radial direction is built integrally with the columnar improved body using a mixture of excavated soil and powdered solidified material, the overhanging portion B that extends outward in the radial direction The amount of settlement due to load is reduced.

Furthermore, by creating a columnar improved body using on-site (excavated soil) and a powder solidification shrine, it is possible to prevent an increase in materials compared to slurry construction methods, etc., and there is no need to dispose of leftover soil.

(2) According to the construction method according to claim 2, excavation, backfilling, and compaction can be performed by changing the forward rotation and reverse rotation of one screw auger 5, thereby improving work efficiency.

(3) According to the manufacturing method of claim 3 and the device of claim 4, the single screw auger 5 can further form a concave portion for forming an overhang, and the work of creating the columnar improved body according to claim 1 can be performed. Efficiency is further improved.

(4) According to the manufacturing method of claim 5 and the press-type enlarging device of claim 6, since the screw auger 5 and the enlarging device 23 are separate, even a small truck auger vehicle can use the hydraulic system to 5 and the enlarging device 23 can be fully utilized.

(5) Furthermore, since the enlarging device of claim 6 forms the concave portion by expanding the excavated hole, the peripheral surface of the excavated hole is strengthened. Moreover, since it is suspended and expanded, it expands biased toward the soft part of the borehole, and can be compacted depending on the softness or hardness of the circumferential surface of the borehole. ,

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a columnar improved body to which the present invention is applied;
7 to 7 are longitudinal cross-sectional views showing the method according to claim 3 in order of steps, FIGS. 8 to 13 are longitudinal cross-sectional views showing another example of the method according to claim 3 in order of steps, and FIG. The figure is a partially cross-sectional side view of a screw auger to which claim 4 is applied, No. 15
The figure is a side view of the entire construction apparatus equipped with the screw auger shown in FIG. 14, FIG. 16 is a longitudinal sectional view showing a modified example of the improved columnar body, and FIGS. 17 to 22 show the construction method according to claim 5. 23 is a perspective view of the entire creation apparatus having the press-type enlarging device according to claim 6, FIG. 24 is a horizontal sectional view of the press-type enlarging device, and FIG. 25 is the same as that of FIG. 24. x
It is a sectional view taken along xv-xxv. A...Column part, B...
Overhanging part, C...Drilling hole, D...Enlarged recess for forming an overhanging part, 5...Screw auger, 6...Shaft part, 15.
...Claw for forming recess, 19...Auger blade, 23...
・Press type enlarging device, 26...Press piece, 29...Hydraulic cylinder Patent applicant Shinsei Basic Industry Co., Ltd.

Claims (6)

[Claims] (1) In a column-shaped improved body created inside an excavation hole using a mixed soil of excavated soil and powdered solidified material discharged from the excavation hole,
A column-shaped improvement body of the ground in which an enlarged overhang extending outward in the radial direction is integrally constructed with the above mixed soil. (2) Excavate the ground by forward rotation of the screw auger and discharge the excavated soil, backfill the excavated soil with mixed soil mixed with powdered solidification material into the excavated hole, and rotate the screw auger in reverse to fill the mixed soil. In the method for constructing a columnar improvement body of ground for compacting, the method according to claim 1, wherein a recess for forming an overhang is formed in the excavation hole and expands outward from the diameter of the excavation hole, and the mixed soil is also backfilled into the recess. A method for forming an improved columnar body for forming the improved columnar body described above. (3) A recess forming claw capable of protruding outward beyond the outer diameter of the auger blade is rotated integrally with the auger to scrape the circumferential surface of the excavation hole to form the overhang forming recess. A method for creating improved columnar bodies. (4) A device for creating a columnar improved body in which a screw auger is provided with a recess-forming pawl that protrudes outward beyond the outer diameter of the auger blade so as to be foldable. (5) A press-type enlarging device separate from the screw auger is suspended by a crane or the like, and a plurality of concave-forming press pieces of the enlarging device press and expand the peripheral surface of the excavation hole to form the concave portion. A method for creating improved columnar bodies. (6) A plurality of hydraulic cylinders that can expand and contract outward in the radial direction are provided on the main body of the enlarging device, which can be freely suspended by a crane, etc., and a plurality of partially cylindrical depression forming press pieces are arranged around the main body in the same circle. A device for creating a columnar improved body arranged on the circumference, each pressing piece being connected to each cylinder, and each pressing piece being able to expand radially outward as the cylinder expands.