JPH10311026A - Dual auger device for soil improvement of earth pressure reduction type - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate influence of the earth pressure upon the foundation of a building adjacent to the improved soil area or an existing underground structure of any sort, for example an underground tunnel, by restricting the movement of the excavation soil by a screw through adoption of partial screw, and reducing the rise of the earth pressure owing to the discharge amount of a coil improving material. SOLUTION: A screw rod 2 is equipped at the tip with an excavating/ agitating head 3 having excavation blades 6, excavation weights 7, and agitation blades. A pair of augers furnished with discharge holes for soil improving material capable of being changed over from the rod tip of the head 3 to the upper part above the agitation blades 6 are installed in line rotatably using coupling members 18 and 21 arranged over and under the head 3 so that a dual auger device is accomplished. Screws 28 of the two augers have a smaller diameter than the excavation blades 6 and are provided partially only in that part of the screw rod 2 mating with the applicable underground structure existing 30, and thereby only the excavation soil in the range corresponding to the length of the screw can be moved up ward by rotation thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground pressure reducing type ground improvement dual auger apparatus for reducing the influence of earth pressure upon improving ground such as soft ground by moving excavated soil with a screw. .

[0002]

2. Description of the Related Art As a means for reducing the influence of earth pressure on existing structures and the like caused by volume expansion of the improved ground due to the injection of the ground improving material during ground improvement by eliminating excavated soil, a method of ground improvement material has been proposed. A method has been already known in which the amount of excavated soil approximately corresponding to the injection amount is removed in advance, or at the same time as the ground improvement, the amount of excavated soil approximately equivalent to the injected amount is discharged to the ground with a screw and prevented. I have.

In addition, as a ground improvement device, a drilling and stirring head provided with a drilling blade and a stirring blade is connected to a tip of a screw rod having a double pipe structure having a screw over its entire length by a joint, and the excavation and stirring head is vertically moved. The outlets are provided, and these outlets are connected to separate supply paths that can be switched on the ground, excavated to a predetermined depth by rotating the screw rod, and then discharged from one of the upper and lower outlets. A single auger device with a structure in which the ground improvement material is mixed with the excavated soil by stirring blades to perform ground improvement, while the amount of excavated soil that almost matches the injection amount of the ground improvement material is discharged to the ground using a screw. Is adopted.

[0004]

In the above conventional apparatus, the excavated soil is removed by the screw extending over the entire length of the screw rod. Therefore, even if the screw outer diameter is formed smaller than the excavation blade, the excavated soil is removed. It is difficult to adjust the amount of excavated soil to an amount that is almost equivalent to the amount of ground improvement material injected. It depends on the work operation, such as the number, excavation or withdrawal speed, and it is very difficult to remove the amount of excavated soil corresponding to the injection amount. Excessive excavated soil can even cause land subsidence. In addition, since the excavation is performed underground by supporting the upper end of the screw rod on the ground, it is difficult to maintain the verticality to the deep part, and the excavation stirring head tilts due to the excavation resistance acting on the excavation tip, It is extremely difficult to penetrate deep inside vertically.

[0005] In addition, a screw rod having a double pipe structure is adopted to supply the ground improvement material to the discharge ports formed at the upper and lower portions of the excavating and stirring head. Since the discharge position of the material has been changed,
Either one of the supply paths is stopped while leaving the ground improvement material, so that the supply path tends to be narrowed by the residue, especially when drawing out, since the supply path of the lower discharge port is not used for a long time, the tendency is large, Unless the supply path is washed to remove the residue when it is pulled out to the ground, it cannot be used later.

The present invention has been conceived in order to solve the above-mentioned conventional problems, and an object of the present invention is to limit the movement of excavated soil by a screw by using a partial screw to improve the ground improvement material. Reduces the increase in earth pressure due to discharge rate, thereby eliminating the effect of earth pressure on existing structures such as foundations of buildings adjacent to the improved ground area, various underground tunnels, seawalls, etc. A new earth pressure reduction type that can be excavated vertically and penetrates deep into the ground even if the upper end of the screw rod is supported on the ground by using a double auger An object of the present invention is to provide a dual auger device for ground improvement.

Another object of the present invention is to form a drilling and stirring head at the tip of a screw rod by using a rod and an outer tube fitted on the outer periphery of the rod so as to be movable up and down, thereby forming a discharge hole above and below the drilling and stirring head. It is an object of the present invention to provide a new soil augmentation ground improvement dual auger device which can reliably perform switching in accordance with the traveling direction of a screw rod by using a common outlet supply path.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a drilling / stirring head having a drilling blade, a drilling weight and a stirring blade at a tip of a screw rod. A pair of augers with a ground improvement material discharge port that can be switched between the two augers are rotatably juxtaposed by connecting members provided above and below the excavating and stirring head to form a double auger, and the screws of both augers are excavated. The diameter of the screw rod is smaller than that of the wing, and the screw rod is partially provided only at the corresponding place such as the existing structure underground, so that only the excavated soil within the screw length range can be moved upward by rotation,
That is.

The excavating and stirring head according to the present invention comprises a hollow rod connected to a screw rod, and an outer tube movably fitted on the outer periphery of the rod only in a vertical direction. And an excavating weight and a stirring blade, a supply path for ground improvement material communicating with the inside of the screw rod is provided in the rod, and a discharge port is opened above the tip of the rod and above the stirring blade. Are provided in the upper and lower portions of the outer tube alternately, and an operating rod for vertically moving the outer tube is connected to the upper portion of the outer tube from a drive unit on the ground.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawing, reference numeral 1 denotes a double auger device, which has a pair of hollow screw rods 2 provided with excavating and stirring heads 3 at the tips thereof.
Is installed. The excavating and stirring head 3 comprises a pair of rods 4 connected to each of the screw rods 2, and a steel outer pipe 5 of a required length fitted around the rod movably only in the vertical direction. The excavation wing 6 and the excavation weight 7 are provided at the tip of 5. A plurality of agitating blades 8, 8 are alternately mounted on the side of the outer tube 5 alternately at different vertical positions and in different protruding directions.

As shown in FIG. 2 and subsequent figures, a supply path 1 for a ground improvement material such as cement slurry communicated with the inside of the screw rod 2 through a connection end 9 therein.
0 is provided up to the tip, and the supply path 10 is connected to both a discharge port 11 formed in the side of the rod tip and a discharge port 12 formed in the side of the rod above the stirring blade 8. ing.

Discharge ports 11 and 12 are provided on the side of the outer pipe 5.
A lower opening 13 and an upper opening 14 are provided alternately, and one of the discharge ports 11 and 12 is opened by the movement of the opening accompanying the vertical movement (about 100 mm) of the outer tube 5, and the ground improvement material Is discharged from the supply channel 10 into the excavated soil. Valves 13a and 14a made of elastic pieces such as rubber which are opened by the discharge pressure are provided at each opening so that only one side thereof can be fastened and opened and closed.

The rod 4 and the outer tube 5 are engaged with each other by the rod 4
Key grooves 15 vertically arranged on the four sides of the center and top outside
A vertically long key 16 penetrating from the outside of the outer tube 5 to the side wall is fitted to the outer tube 5 so that the outer tube 5 can be moved up and down within the length range of the key groove 15. Thus, the rod 4 and the outer tube 5 are integrally formed in the circumferential direction so that the rotational force is transmitted to the outer tube 5 so that the outer tube 5 can be rotated for excavation and stirring.

Each of the keys 16 has a convex cross section in a plan view, and as shown in FIGS. 3 and 4, the head 16a extends outward from a long hole 5a formed in the side wall of the outer tube 5. As shown in FIG. A head 16a fitted in the key groove 15 and protruding from the outer tube side wall is provided by an annular key holder 17 attached around the outer tube so as not to fall off.

The key ring 17 has the head 1 inside.
A pair of semicircular members 17a each having a fitting groove 17b of 6a and integrally formed with ear pieces 17c at both ends, and a pair of the semicircular members 17a are put together around the outer tube and then inserted into the ear pieces 17c. And is fastened around the outer tube by the bolt 17d.
In such a mounting structure of the key 16, the key ring 17
, The key 16 can be removed from the outer tube 5, thereby releasing the connection between the rod 4 and the outer tube 5 by fitting the key groove 15 and the key 16 and removing the key from the rod 4. The tube 5 can be withdrawn as needed.

Reference numeral 18 denotes a connecting member extending between the upper end and the lower portion of the outer tube 5. The connecting member 18 is fitted over an outer tube 5 by fitting an annular mounting member 20 between upper and lower flanges 19 provided on the outer tube 5. At both ends, protruding pieces for steadying are provided. The outer tubes 5 are supported by each other by the connecting member 18 and are rotatably connected to each other.

Reference numeral 21 denotes a connecting member provided over the distal end portions of the pair of screw rods 2, and is mounted by fitting an annular mounting member 23 between upper and lower flanges 22 provided on the screw rod 2 similarly to the connecting member 18. Stabilizers 24 are provided on the four sides at both ends.

Reference numeral 25 denotes an operating rod for the outer tube 5, which is provided vertically across a piston 27 of a hydraulic operating device (not shown) on the side of the drive device 26 and the connecting member 18 on the upper portion of the excavating and stirring head.
By operating the outer tube 5 with the operating rod 25, the discharge port 1
1 and 12 are alternately opened. Further, by adopting a hollow tube as the operating rod 25 and providing a sensor capable of electrically measuring the inclination value in the center thereof, the operating rod 25 can be used also as an inclination measuring member.

Reference numeral 28 denotes a screw for excavated soil movement provided on the screw rod 2, which is partially provided at a position corresponding to the existing underground structure 30. The outside diameter of the screw 28 is smaller than the outside diameter of the excavating wing 6, and is formed so that only the excavated soil within the screw length range can be moved upward by rotation. Due to the movement of the excavated soil at the screw position, a predetermined amount of excavated soil corresponding to the movement is eventually discharged to the ground. The partial movement of the excavated soil by the screw 28 is performed by the excavation and stirring head 3 by the rotation of the screw rod 2.
This is done simultaneously with the mixing of the soil improvement material at the same time, so even if the volume increases due to the discharge amount of the soil improvement material, most of the increase is offset by the movement amount of the excavated soil, and the earth pressure Is suppressed.

In the double auger apparatus 1 having the above-described configuration, the excavation underground is performed while rotating the pair of excavating and stirring heads 3 while changing their directions to the right and left. The pair of excavating and stirring heads 3 are integrated by connecting members 18 and 21, and the stabilizers 24 are provided on both sides on both sides to support the upper ends of the pair of screw rods 2 on the ground and excavate to a deep part in the ground. Even when the drilling is performed, the verticality is maintained, and even if the drilling resistance exerts a large force on the tip of the drilling, the drilling and stirring head 3 hardly tilts, and drills vertically into the ground to penetrate.

The discharge port 11 by moving the outer tube 5 up and down,
Twelve switching operations are performed after the penetration reaches a predetermined excavation depth. For example, when a case where the excavation depth is 15 m is described, only excavation is performed until the penetration reaches 12 m. From the remaining 3m to the fixing depth, the operating rod 25
As a result, the outer pipe 5 is moved upward to open the discharge port 11 at the tip, and excavation is performed while discharging the ground improvement material of cement slurry, which has been fed into the supply path 10 through the inside of the screw rod 2, into the excavated soil. The discharged cement slurry and excavated soil are agitated and mixed by the rotation of the agitating blade 8 to be improved. However, as a tip treatment, the excavated and agitated head 3 is pulled up by about 1 m from the fixing depth to perform re-penetration. At this time, the injection of the cement slurry is stopped and only stirring is performed.

When the above-mentioned front end processing is completed, the process shifts to lifting up and stirring. In this case, since the discharge port 11 at the tip is located below the stirring blade 8, it is not possible to mix the excavated soil with the stirring blade 8 while stirring the slurry from the discharge port 11. Switch to 12. This switching is performed by moving the outer tube 5 downward by the operating rod 25, displacing the opening 13 from the discharge port 11 to the lower side, and overlapping the opening 14 with the upper discharge port 12.

After the switching, the supply of the cement slurry is started, and when the drilling and stirring head 3 is pulled up while rotating together with the screw rod 2, the cement slurry from the discharge port 12 is stirred and mixed with the excavated soil by the stirring blade 8. The ground is being improved.

On the screw rod side, the excavated soil of the screw 28 is
That is, only the excavated soil corresponding to the existing underground structure 30 moves upward by the rotation of the screw 28. The movement of the excavated soil is limited to the length of the screw 28, and the amount of movement is limited because the screw 28 has a small diameter. Therefore, the excavated soil does not move over a wide area. Only the allowable range 29 that does not affect the earth pressure is
It is performed to the extent that the density of excavated soil becomes coarse.

Even if the volume of the improved ground increases due to the movement of the cement slurry due to this movement, the increase is not
8 will be offset by the amount of excavated soil moved,
The rise in earth pressure is extremely small. The movement of the excavated soil by the screw 28 is partial, and the excavated soil at the position without the screw 28 is pushed up by the excavated soil moved upward from the screw position, and furthermore, to some extent depending on the density state of the excavated soil. However, the excavated soil corresponding to the increased volume is eventually discharged to the ground. In addition, since the excavated soil is not moved in a portion where the screw 28 is not provided, unnecessary excavated soil is prevented from being discharged.

Also, when the excavating and stirring head is double-structured inside and outside, it is only necessary to fit the outer tube using a key or the like on the outer periphery of the hollow rod, so that the discharge port can be switched easily. It can be easily operated because no special operation is required just by moving up and down, and the ground improvement material supply path can be shared and used at all times. Supply failure due to solidification of the residual ground improvement material, which is likely to occur when changing, can be prevented, and the supply path can be easily cleaned when pulled out to the ground, making maintenance and management of the equipment easy and operating with earth pressure Since there are no difficult points, it can be used for deep ground improvement.

[Brief description of the drawings]

FIG. 1 is an elevational view of a main part of an earth pressure reducing type ground improvement dual auger apparatus according to the present invention.

FIG. 2 is a partially vertical elevation view of a portion of a digging and stirring head.

FIG. 3 is a partial vertical sectional side view showing a mounting state of a key.

FIG. 4 is a plan sectional view of the same.

FIG. 5 is a plan sectional view (A) taken along the line AA in FIG.
It is a plane sectional view (B) in the B line.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 double auger device 2 screw rod 3 excavating and stirring head 4 rod 5 outer tube 6 excavating blade 7 excavating weight 8 agitating blade 9 connecting end 10 supply path 11 tip outlet 12 upper outlet 13 lower opening 14 upper opening 15 key Groove 16 Key 17 Key holder 18 Connecting member 25 Operating rod of outer tube 28 Screw 29 Allowable range 30 Underground existing structure

Claims (2)

[Claims] An excavating and stirring head having an excavating blade, an excavating weight and a stirring blade at a tip of a screw rod, and a discharge port of a ground improvement material switchable between the rod end of the excavating and stirring head and an upper portion of the stirring blade. A pair of augers are opened, and are rotatably juxtaposed by connecting members provided above and below the excavating and stirring head to form a double auger. An earth pressure reduction type ground improvement method characterized in that the excavated soil within the screw length range is configured to be able to move upward by rotation only partially at a corresponding location such as a middle existing structure. Ream auger device. 2. The excavating and stirring head comprises a hollow rod connected to a screw rod, and an outer tube fitted movably only in the vertical direction on the outer periphery of the rod. And a stirring blade are provided, and a supply path for the ground improvement material communicating with the inside of the screw rod is provided in the rod, and a discharge port is opened above the tip of the rod and above the stirring blade, and the discharge ports are alternately formed. 2. An earth pressure reducing type ground improvement according to claim 1, wherein openings for opening and closing are provided at an upper portion and a lower portion of the outer tube, and an operating rod for moving the outer tube up and down is connected to the upper portion of the outer tube from a driving device on the ground. Double auger device.