JP2008196249A - Ground reinforcing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ground reinforcing method for constructing a strong crushed stone pile by throwing crushed stones into an excavated hole formed in the ground, and tamping down the thrown crushed stones in each of a plurality of divided sections by using a drill and a hammer in collaboration. <P>SOLUTION: The excavated hole 30 is formed in the ground G by the normal rotation of the drill 12. The natural crushed stones 33 are compressed into the excavated hole 30 by the reverse rotation of the drill 12 while being thrown into the excavated hole 30. Next, the rotation of the drill 12 is stopped and an air hammer 13 is independently moved up and down to apply shocks to the thrown crushed stones 33 to tamp them down. The excavated hole 30 is filled with the tamped-down crushed stones 33 to form the crushed stone pile to the ground surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a ground reinforcement method for constructing a crushed stone pile on the ground, thereby changing the ground, particularly the soft ground, to a strong ground and firmly supporting a building or the like.

  Conventionally, as a means of improving soft ground to strong ground, columnar cement and steel pipe piles are buried in the ground, but cement and steel pipes deteriorate or rust in the ground. Hazardous substances are generated, causing environmental pollution, and it is difficult to build a solid ground for a long time.

Further, as another means for improving a soft ground to a strong ground, as disclosed in Patent Document 1 described later, pressurized water and compressed air are injected from the lower end of the double pipe to form a drilling hole, and the excavation is performed. A construction method is already known in which a crushed stone pile is constructed by filling crushed stones in a hole.
JP 2003-113607 A

  By the way, the thing disclosed in the above-mentioned patent document 1 needs to treat muddy water generated as a result of using pressurized water as industrial waste, and there is a secondary problem of environmental pollution. The use of air complicates the construction method of the crushed stone pile, and it is necessary to treat the muddy water.

  This invention is made | formed in view of this situation, and it aims at providing the novel ground reinforcement construction method which solved the said problem.

In order to achieve the above-mentioned object, the invention according to claim 1 is directed to a ground using a drill and a hammer supported at the lower end of the drill so as to be rotatable integrally with the drill and movable up and down. It is a ground reinforcement method to reinforce the ground by building a crushed stone pile,
The first step of drilling holes in the ground by repeatedly descending and ascending toward the ground while driving the drill and hammer forward together, and stopping the rotation of the drill and hammer, The second step of inserting into the drilling hole, the third step of pushing the drill and hammer reversely while pushing a predetermined amount of crushed stone into the drilling hole and pushing the input crushed stone into the drilling hole, and stopping the rotation of the drill The fourth step of impacting and crushing the input crushed stone by moving the hammer up and down independently, and then repeating the second to fourth methods to fill the crushed stone into the excavation hole It is characterized by building a crushed stone pile to the surface.

  In order to achieve the object, the invention described in claim 2 is characterized in that, in the object described in claim 1, the crushed stone is constituted by crushing natural stone.

  According to the invention described in each claim, a strong crushed stone pile can be constructed on the ground by a simple construction method by cooperation of rotation of a drill and hammering of a hammer connected to the drill.

  Moreover, according to the invention of Claim 2, soil pollution and environmental destruction do not occur by using natural crushed stone as crushed stone.

  Embodiments of the present invention will be specifically described below based on the embodiments of the present invention illustrated in the accompanying drawings.

  FIG. 1 is a perspective view showing a state in which a building is constructed on a plurality of crushed stone piles made on the ground by the ground reinforcement method of the present invention, an overall side view of the ground reinforcement device for carrying out the ground reinforcement method of the present invention, 3 is an enlarged cross-sectional view taken along the line 3-3 in FIG. 2, FIG. 4 is a view taken in the direction of arrow 4 in FIG. 3, and FIGS.

  First, the configuration of the ground reinforcement device will be described with reference to FIGS.

  In FIG. 2, a turntable 2 is mounted on a chassis 1 of a work vehicle V so as to be turnable around a vertical axis, and an extendable boom 3 is pivotally supported on the turntable 2 so as to be able to be lifted. A telescopic cylinder 5 is connected between the telescopic boom 3 and the swivel base 6, 7, and the telescopic boom 5 is driven up and down around four pivots by the telescopic operation of the telescopic cylinder 5.

  A drive shaft 9 is suspended and connected to the tip of the telescopic boom 3 via a rotary motor 8. The drive shaft 9 is configured by connecting a plurality of drive shaft units 9 a, 9 b, 9 c through joints 10, 10, and a drill 12 is integrally formed at the lower end of the drive shaft 9 through a joint 11. A hammer, in this embodiment an air hammer 13, is connected to the lower end of the drill 12 by a spline connection 14, and the air hammer 13 is independent of the drill 12 as shown by an arrow in FIG. 3. It can be raised and lowered and can rotate integrally with the drill 12. The drill 12 is provided with a screw 12s, and the air hammer 13 is provided with a screw 13s and a stirring claw 13m at an upper portion thereof and a hammer main body 13h at a lower portion thereof. The hammer 13 is formed in the shape of a truncated cone downward so that the crushed stone can be easily compacted, and a bit 15 is provided on the conical surface thereof.

  As shown in FIG. 2, the rotary shaft 9 is connected with a compressed air supply means A for driving the air hammer 13 in a vertical direction. The compressed air supply means A includes a compressor 20 installed on the ground and an air tank 22 connected to an outlet of the compressor 20 via an air hose 21, and an outlet of the air tank 22 is connected via another air hose 23. The swivel joint 24 provided on the rotary shaft 9 is connected. The compressed air from the compressor 20 is stored in the air tank 22 and then guided into the drill 12 through the swivel joint 24 and the drive shaft 9, and the free piston 25 provided in the drill 12 is operated to cause the air hammer 13 to move. Reciprocates vertically.

  Since the operation of the air hammer 13 using compressed air employs a conventionally known structure, a detailed description thereof will be omitted.

  Next, a procedure for constructing the crushed stone pile P on the ground G by the cooperation of the drill 12 and the hammer 13 will be described with reference to FIGS.

(1) Excavation work of the excavation hole As shown in FIG. 5 (A), the tip of the air hammer 13 is applied to a position to be excavated on the ground G, the drill 12 is rotated forward (right rotation), and lowered to lower the position shown in FIG. As shown in (1), the ground G is drilled to a predetermined depth. Next, as shown in FIG. 5C, the drill 12 stops its forward rotation and pulls it up to the ground. Here, the excavated soil adhering to the drill 12 and the air hammer 13 is placed on the screws 12s and 13s and discharged.

  By repeating the excavation work shown in FIGS. 5B and 5C, as shown in FIG. 5D, an excavation hole 30 having a predetermined depth is drilled in the ground G, and the excavation work is completed.

  When the excavation work is finished, as shown in FIG. 5E, the drill 12 stops its rotation and is pulled up from the excavation hole 30 to the ground, and finally the excavated soil attached to the drill 12 and the air hammer 13 is finally removed. remove.

(2) Inserting crushed stone and compacting operation As shown in FIG. 6 (F), in the excavation hole 30 where excavation has been completed, the drill 12 that has stopped rotating is placed with the lower end of the air hammer 13 at the bottom of the excavation hole 30. Insert until it reaches. Next, as shown in FIG. 6 (G), the drill 12 is reversely rotated (turned to the left) while a predetermined amount (first time portion) of crushed stone 33 crushed from natural stone is gradually put into the digging hole 30. Due to the reverse rotation of the drill 12, the crushed stone 33 introduced into the excavation hole 30 is sequentially pushed toward the bottom of the excavation hole 30 by the screw 12 s of the drill 12.

  Next, as shown in FIG. 6 (H), after the reverse rotation of the drill 12 is stopped, the drill 12 is slightly lifted to form a slight gap between the upper surface of the input crushed stone 33 and the air hammer 13, and then the compression is performed. With the operation of the air supply means A, the air hammer 13 is moved up and down, hammering is applied to the input crushed stone 33, and the input crushed stone 33 is compacted.

  Next, as shown in FIG. 7 (I), the drill 12 is reversed while a predetermined amount (second time) of crushed stone 33 is gradually put into the drilling hole 30 as in the step shown in FIG. 6 (G). Turn counterclockwise. Thereby, the input crushed stone 33 is sequentially pushed onto the crushed stone 33 (for the first time) that has already been compacted.

  Next, as shown in FIG. 7 (J), after the reverse rotation of the drill 12 is stopped, the drill 12 is pulled up to form a slight gap between the upper surface of the crushed stone 33 and the air hammer 13, and then the compressed air supply is performed. By the operation of the means A, the air hammer 12 is moved up and down to hammer the input crushed stone 33, and the input crushed stone (second time) is compacted on the already crushed crushed stone 33.

  As described above, by repeating the operations shown in FIGS. 6 (G) to 7 (J), natural crushed stones that have been divided and solidified over the entire area of the excavation hole 30 as shown in FIG. 7 (K). By 33, the crushed stone pile P can be constructed to the ground surface.

  As described above, according to this ground reinforcement method, the crushed stone 33 introduced into the excavation hole 30 is divided into a plurality of pieces and crushed by hammering, so that the crushed stone 33 can be efficiently crushed and solidified. A strong crushed stone pile P can be quickly constructed.

  And by building the crushed stone pile P by this ground reinforcement construction method, the soft ground can be changed to a strong ground, and this ground can be protected from the impact and liquefaction at the time of earthquake. As shown in FIG. By constructing the building B on the ground reinforced with piles, the building B can be firmly and stably supported over a long period of time.

  Moreover, since the natural crushed stone 33 is used, the problem of soil contamination or environmental destruction does not occur, it is not necessary to take measures against it, and a significant cost reduction can be achieved.

  As mentioned above, although the Example of this invention was described, this invention is not limited to the Example, A various Example is possible within the scope of the present invention.

  For example, in the above-described embodiment, the case where an air hammer is used as the hammer has been described, but other hammers such as a hydraulic hammer and an electric hammer may be used instead.

The perspective view which shows the state which built the building on the some crushed stone pile made in the ground by this invention ground reinforcement construction method Overall side view of the ground reinforcement device for carrying out the ground reinforcement method of the present invention Enlarged cross-sectional view along line 3-3 in FIG. 4 arrow view of FIG. The figure which shows the procedure of the ground reinforcement construction method of this invention The figure which shows the procedure of the ground reinforcement construction method of this invention The figure which shows the procedure of the ground reinforcement construction method of this invention

Explanation of symbols

12 ... Drill 13 ... Hammer (Air Hammer)
30 ... Drilling hole 33 ... Crushed stone G ... Ground P ... ... Crushed stone pile

Claims (2)

Using a drill (12) and a hammer (13) which is rotatable at the lower end of the drill (12) and is supported so as to be movable up and down, a ground pile (P) ) To reinforce the ground (G),
While both the drill (12) and the hammer (13) are driven to rotate forward, the descent hole (30) is drilled in the ground (G) by repeatedly descending and rising from the ground (G) toward the ground (G). A first step;
A second step of stopping the rotation of the drill (12) and the hammer (13) and inserting them into the drilling hole (30);
A third step of pushing the drill (12) and the hammer (13) in reverse to push the thrown crushed stone (33) into the digging hole (30) while putting a predetermined amount of crushed stone (33) into the digging hole (30); ,
A fourth step in which the rotation of the drill (12) is stopped, the hammer (13) is moved up and down independently to impact the input crushed stone (33),
Thereafter, the second to fourth steps are repeated to fill the excavated hole (30) with the crushed stone (33) and to build the crushed stone pile (P) to the ground surface. Construction method.   The ground reinforcement method according to claim 1, wherein the crushed stone (33) is formed by crushing natural stone.

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