Buried pile extraction method and pile extraction system

Abstract

To solve the problem that a buried pile needs to be lifted up to the ground in its entirety to be pulled out while being surrounded by a casing, and the danger of the work increases greatly when the buried pile is large.SOLUTION: A pile extraction method includes a casing excavation step of inserting a roughly cylindrical hollow casing into the ground so that the casing surrounds a buried pile, a chucking device insertion step of inserting a chucking device into the casing after the casing excavation step, a chucking step of chucking the buried pile with the chucking device after the chucking device insertion step, a pile extraction step of pulling the chucked buried pile to the ground after the chucking step, and a casing removal step of pulling the casing to the ground after the pile extraction step.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for extracting buried piles buried in the ground, and more particularly to a method and system for safely and efficiently removing existing buried piles in construction and civil engineering works. [Background technology]

[0002] During construction and civil engineering work, it may become necessary to remove buried piles that have already been buried underground as the foundations of buildings and structures. Buried piles play an important role as the foundations of structures, but when the structure is demolished, renovated, or redeveloped, it is essential to remove these piles. The removal of buried piles is a very important process, as it directly affects the safety and speed of subsequent construction work.

[0003] A conventional pile extraction method involves placing a casing over an existing buried pile, drilling a hole to "sever" the connection between the ground and the existing pile, then chucking (fixing) the buried pile and pulling it up while still inside the casing, a method known as chucking. With the chucking method, the entire buried pile is pulled up while still inside the casing, so even damaged or broken piles can be safely and reliably pulled out. In addition, by ejecting filler material from the tip of the casing when pulling up the casing, it is possible to backfill the pile hole from its deepest point, and filler material can be backfilled along the entire length of the extraction hole.

[0004] For example, the buried pile extraction device described in Patent Document 1 has a mechanism for holding the tip of the buried pile with a chucking claw and pulling it up to the ground. This device enables the chucking claw to protrude from the tip of the casing, enabling the buried pile to be completely extracted. It also has a function to protect the hydraulic cylinder used to operate the chucking claw, improving the durability and operability of the device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-154541 Summary of the Invention [Problem to be solved by the invention]

[0006] However, with conventional pile extraction methods, the buried pile must be pulled out while still enclosed in its casing, which necessitates lifting the entire buried pile above ground, making the work significantly more dangerous when the buried pile is large. Furthermore, because the casing is also pulled out at the same time as the buried pile is extracted, there is a risk that the inner wall of the hole may collapse after the casing is removed, reducing the efficiency of subsequent work such as backfilling.

[0007] The buried pile extraction method and system of the present invention provides an effective solution to these problems. It has been discovered that leaving the casing in the ground stabilizes the inner walls of the hole after the pile extraction operation while eliminating the need to completely lift the buried pile above ground. This method allows for the safe disposal of particularly heavy piles or piles that are structurally weak. Furthermore, when performing subsequent operations such as backfilling by injecting filler material into the casing, the hole after the pile extraction operation can be efficiently and reliably backfilled. This not only improves work safety, but also shortens construction time and reduces costs. [Means for solving the problem]

[0008] (1) The pile extraction method according to the present invention is characterized by including a casing excavation step of inserting a casing having a roughly cylindrical hollow shape into the ground so that the casing surrounds a buried pile; a chucking device insertion step of inserting a chucking device into the casing after the casing excavation step; a chucking step of chucking the buried pile with the chucking device after the chucking device insertion step; a pile extraction step of pulling the chucked buried pile to the ground after the chucking step; and a casing removal step of pulling the casing to the ground after the pile extraction step.

[0009] (2) The above-mentioned pile extraction method further includes a backfilling step of injecting a solidification material into the casing after the pile pulling step and before the casing removal step.

[0010] (3) In the above-mentioned pile extraction method, the pile extraction upper step clamps and chucks the peripheral surface (not the tip) of the buried pile.

[0011] (4) In the above-described pile extraction method, the pile extraction step cuts off a portion of the buried pile while leaving the portion of the buried pile exposed above ground.

[0012] (5) The chucking device according to the present invention comprises a main body portion having an approximately cylindrical hollow shape capable of enclosing a buried pile inside, and at least a pair of chuck portions provided on the main body portion, extending from the main body portion toward the tip, and clamping the buried pile, and the chuck portions are characterized in that they have clamping surfaces extending along the cylindrical shape of the main body portion.

[0013] (6) The chucking device includes three or more of the chucking portions.

[0014] (7) The pile extraction system of the present invention comprises a casing having an approximately cylindrical hollow shape, and a chucking device that is inserted into the inside of the casing and chucking the buried pile, and the chucking device comprises a main body portion having an approximately cylindrical hollow shape that can enclose the buried pile inside, and at least a pair of chuck portions that are provided on the main body portion, extend from the main body portion toward the tip, and clamp the buried pile. [Effects of the Invention]

[0015] According to the present invention, by separating the casing and the chucking device, there is no need to lift the entire buried pile to the ground by cutting the buried pile in half, and by removing the buried pile while leaving the casing in place, subsequent work such as backfilling can be carried out reliably. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a flow diagram of a pile extraction method according to an embodiment of the present invention. [Figure 2] FIG. 1 is a diagram showing a specific example of a flow of a pile extraction method according to an embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing a specific example of a continuation of the flow shown in FIG. 2. [Figure 4] 1A and 1B are diagrams showing a chucking device according to an embodiment of the present invention, in which (A) is a side view and (B) is a cross-sectional view taken along B1-B1 in (A). [Figure 5] FIG. 5 is a side cross-sectional view of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] <Pile removal method> Hereinafter, a pile extraction method S according to an embodiment of the present invention will be described with reference to the drawings.

[0018] The pile extraction method S is carried out according to the flow shown in Figure 1. That is, the pile extraction method S includes a casing preparation step (S1), a casing excavation step (S2), a pile edge severing step (S3), a chucking device insertion step (S4), a chucking step (S5), a pile extraction step (S6), a stirring device preparation step (S7), a backfilling step (S8), a stirring device removal step (S9), and a casing extraction step (S10).

[0019] By implementing the pile extraction method S, piles buried in the ground (buried piles K) can be pulled out and removed from the ground. The buried piles K are piles buried in the ground as the foundations of buildings, etc., and include, for example, cast-in-place reinforced concrete piles and concrete-filled steel pipe piles.

[0020] The pile extraction method S is realized by a pile extraction system KS. The pile extraction system KS includes a base machine 3 such as a pile driver, a rotation drive device 2 such as an auger that is suspended from the tip of a leader 3a of the base machine 3, a casing 1 connected to the rotation drive device 2 via a swivel, a chucking device 5, an agitator 6, etc. The base machine 3 may be a crawler crane with an arm instead of the leader 3a.

[0021] In the casing preparation step (S1), as shown in Figure 2(A), a casing 1 for carrying out the pile extraction method S is prepared. Specifically, a support 4 that enables the rotary drive device 2 to be raised and lowered is attached to the leader 3a of the base machine 3, and the casing 1 is connected to the rotary drive device 2 attached to the support 4. The base machine 3 and the leader 3a are moved so that the casing 1 is directly above the buried pile K.

[0022] The casing 1 has a roughly hollow cylindrical shape and an inner diameter larger than that of the buried pile K. The casing 1 is appropriately provided with piping (not shown) for supplying water, a mud-forming agent such as bentonite, etc. to the tip 55 of the casing 1. This mud-forming agent can reduce the hardness of the stratum.

[0023] The casing 1 is buried in the ground during pile extraction work, preventing soil collapse on the side walls of the hole being drilled and protecting the environment inside the casing 1. The rotary drive device 2 is connected to the tip of the leader 3a of the base machine 3, and rotates the casing 1 around a vertical axis. The casing 1 is connected to the rotary drive device 2, and is configured to be able to rise and fall as the rotary drive device 2 rises and falls vertically.

[0024] In the casing excavation step (S2), the casing 1 is excavated into the ground as shown in Fig. 2(B). Specifically, the casing 1 has excavation teeth (not shown) at its tip for excavating the stratum, and the casing 1 is rotated by the rotation of the rotary drive device 2, and the excavation teeth excavate the ground G while the casing 1 is excavated into the ground.

[0025] At this time, to facilitate the excavation of the casing 1, a mud-forming agent (such as water or bentonite) is supplied into the hole. This reduces the hardness of the stratum and reduces friction. The rotary drive device 2 is attached to a support 4 so that it can be raised and lowered, so that the casing 1 is pushed down vertically by lowering the rotary drive device 2. The lowering of the rotary drive device 2 continues until the casing 1 reaches the desired depth.

[0026] By drilling the casing 1 into the ground, earth and sand on the side of the excavation hole will not be excavated into the casing 1, ensuring safety during work. The casing 1 is generally drilled into the ground to the depth of the tip of the buried pile K.

[0027] In the pile edge severing step (S3), the edge of the buried pile K is severed from the surrounding ground, as shown in Figure 2(C). That is, adhesive forces are generated between the buried pile K and the surrounding ground due to friction, earth pressure, etc., and this adhesive force is severed in the pile edge severing step. For example, the pile edge is severed by injecting high-pressure water into the surrounding area from the tip of a casing 1 that has been excavated to a depth below the bottom of the buried pile K, physically severing the bond between the pile and the ground (hydraulic fracturing method).

[0028] In addition to the hydraulic fracturing method, pile edge severance may be achieved by a vibration method in which a vibrating machine is used to vibrate the pile, thereby reducing friction between the pile and the ground, or by a chemical injection method in which a specific chemical is injected around the pile to soften the ground and reduce its adhesive strength. Once the pile edge has been severed, the buried pile K can be pulled out. After the pile edge has been severed, the rotary drive device 2 is separated from the casing 1.

[0029] In the chucking device insertion step (S4), as shown in Fig. 2(D), the chucking device 5 for clamping and extracting the buried pile K is inserted to a position where it will clamp the buried pile K. Specifically, while the casing 1 excavated into the ground is maintained, the chucking device 5 is inserted into the ground through the inside of the casing 1, which has a roughly cylindrical hollow shape, until the chuck portion 52 of the chucking device 5 reaches the periphery of the buried pile K.

[0030] Here, the chucking device 5 is connected to the rotary drive device 2, which has been previously separated from the casing 1, via a special swivel 8. The special swivel 8 is connected to a rod 7 of an optimum length depending on the position at which the chucking device 5 chucks the buried pile K.

[0031] In the chucking step (S5), as shown in Fig. 2(E), the chuck portions 52 of the chucking device 5 clamp and hold the buried pile K. Specifically, two pairs of chuck portions 52 of the chucking device 5, which will be described later, are displaced inward and come into contact with the circumferential surface of the buried pile K so as to clamp and hold the buried pile K. This holding force is adjusted by the clamping mechanism 58 of the chucking device 5 to be sufficient to hold the buried pile K but not to damage the pile.

[0032] In the pile extraction step (S6), as shown in Fig. 2(F), the buried pile K is pulled up and extracted from underground while the chucking device 5 is rotated by the rotary drive device 2. Specifically, with the buried pile K held by the chucking device 5 with a predetermined holding force, the rotary drive device 2 is operated, and while rotating the chucking device 5, the rotary drive device 2 is raised until the buried pile K emerges above ground.

[0033] In this step, depending on the weight and condition (e.g., breakage or damage) of the buried pile K, a part of the buried pile K may be cut off while a part of the buried pile K is exposed above ground. In this way, it is not necessary to lift the entire buried pile K above ground, and the safety of the work can be improved. After the pile extraction step, the rotation drive device 2 is separated from the chucking device 5.

[0034] In the agitator preparation step (S7), an agitator 6 for agitating the solidification material is prepared, as shown in FIG. 3(G). Specifically, the agitator 6 is attached to the support 4 via the rotation drive device 2. The agitator 6 is selected to have an optimum length dimension so that it can reach the tip of the casing 1. In this embodiment, the agitator 6 is a conventionally well-known screw device that has approximately the same length as the casing 1.

[0035] In the backfilling step (S8), as shown in Fig. 3(H), a solidification material is injected into the casing 1 to perform backfilling. Specifically, the agitator 6 is inserted up to near the tip of the casing 1, and the agitator 6 is rotated and pulled up while the solidification material is injected into the casing 1. As a result, the solidification material is filled into the casing 1 while being agitated, so that the solidification material can be backfilled with high quality.

[0036] In the agitator removal step (S9), as shown in FIG. 3(I), the agitator 6 is detached and removed from the rotary drive device 2. Specifically, the agitator 6 is removed from the rotary drive device 2 in a state where the entire agitator 6 is exposed above ground. At this time, the casing 1 remains underground.

[0037] In the casing removal step (S10), as shown in Figure 3 (J), the rotary drive unit 2 from which the agitator 6 has been removed is reconnected to the casing 1, and the rotary drive unit 2 is pulled up to remove the casing 1. At this time, the solidification material filled inside the casing 1 spreads to the earthen wall outside the casing 1 and fixes the earthen wall, allowing the hole drilled by the casing 1 to be backfilled with an appropriate hardness.

[0038] In this embodiment, the base machine 3 and the rotary drive device 2 are the same for each step. That is, the rotary drive device 2 is equipped with the casing 1 in the casing preparation step, the casing excavation step, and the pile edge severing step, with the chucking device 5 in the chucking device insertion step, the chucking step, and the pile extraction step, with the agitator 6 in the agitator preparation step, the backfilling step, and the agitator removal step, and with the casing 1 again in the casing removal step.

[0039] <Chucking device> As shown in FIG. 4, the chucking device 5 includes a main body 51 having a hollow cylindrical shape, a chuck portion 52 that clamps the buried pile K, and a ring portion 53 that protects the chuck portion 52. The main body 51 has an inner diameter that is large enough to enclose the buried pile K inside. The chuck portion 52 is attached to the outer surface of the main body 51 and extends beyond the main body 51 toward the tip. In this embodiment, the chucking device 5 includes two pairs of chuck portions 52. The ring portion 53 is formed in a roughly ring shape, is open to the inside, and includes recesses 54 that are equally spaced apart. The recesses 54 house the chuck portions 52.

[0040] The chuck portion 52 includes a tip portion 55 for clamping the buried pile K, a support portion 56 attached to the main body portion 51 and supporting it, a stroke mechanism 57 for extending and retracting the tip portion 55 relative to the support portion 56, and a clamping mechanism 58 for displacing the tip portion 55 inward and outward. The tip portion 55 has a clamping surface 55a for clamping and holding the buried pile K.

[0041] Each stroke mechanism 57 is composed of a well-known cylinder. Each clamping mechanism 58 has multiple rotation shafts 58a connected to the tip 55, and the tip 55 is displaced by rotating the rotation shafts 58a. The clamping surface 55a of the tip 55 has a curved surface that follows the side peripheral surface of the buried pile K (see Figure 4(B)), and has a surface that is approximately parallel to the peripheral surface of the buried pile K.

[0042] As shown in Figure 5, when chucking a buried pile K, in the chucking device 5 inserted to a predetermined depth, the stroke mechanism 57 extends the tip 55, and the clamping mechanism 58 displaces the tip 55 inward, and the buried pile K is chucked by the clamping surfaces 55a of the multiple tip parts 55. In other words, the chucking device 5 clamps and holds the side peripheral surface of the buried pile K. After the buried pile K is pulled up to the ground, the clamping mechanism 58 displaces the tip 55 outward, releasing the clamped state, while the buried pile K is held by another means.

[0043] In this embodiment, the pile extraction system KS has been described as having a configuration in which the rotation drive mechanism is attached to the support 4. However, the pile extraction system KS may have a configuration in which the rotation drive mechanism 2 is attached directly to the base reader 3a without using the support 4.

[0044] In the present embodiment, the chucking device 5 has been described as having four (two pairs) of chuck portions 52. However, the chucking device 5 can chuck the buried pile K as long as it has at least two (one pair) of chuck portions 52. The chucking device 5 may also have three or more chuck portions 52. In this case, it is desirable that the multiple chuck portions 52 are arranged at equal intervals.

[0045] In this embodiment, the clamping surface 55a of the tip portion 55 extends in the vertical direction. However, the clamping surface 55a of the tip portion 55 may be tapered so as to easily clamp the buried pile K.

[0046] The pile extraction method S and the chucking device 5 according to this embodiment have been described above. However, the pile extraction method S and the chucking device are not limited to the above embodiment, and other configurations may be used within the scope of achieving the object of the invention. [Industrial Applicability]

[0047] The present invention can be used to remove buried piles. [Explanation of symbols]

[0048] K Buried pile S Pile extraction method KS Pile Pulling System 1 casing 2 Rotational drive unit 3 Base Machine 4 pillars 5 Chucking device 6 Stirring device 7 Rod 51 Main body 52 Chuck part 53 Ring section 54 Recess 55 Tip 55a Clamping surface 56 Support part 57 Stroke mechanism 58 Clamping mechanism

Claims

1. a casing excavation step of excavating a casing having a generally cylindrical hollow shape into the ground so that the casing surrounds the buried pile; a chucking device inserting step of inserting a chucking device into the casing after the casing excavation step; After the chucking device inserting step, a chucking step of chucking the buried pile by the chucking device; After the chucking step, a pile extraction step is performed to pull up the chucked buried pile to the ground. A pile extraction method characterized by including, after the pile extraction step, a casing extraction step of pulling the casing up to the ground.

2. Furthermore, after the pile pulling step and before the casing removal step, The pile extraction method according to claim 1 , further comprising a backfilling step of injecting a solidification material into the casing.

3. The pile extraction method according to claim 1 , wherein the pile extraction step comprises clamping and chucking the peripheral surface of the buried pile.

4. The pile extraction method according to claim 3 , wherein the pile extraction step cuts off a part of the buried pile in a state where a part of the buried pile is exposed above ground.

5. a main body having a generally cylindrical hollow shape capable of enclosing a buried pile therein; At least one pair of chuck portions are provided on the main body portion, extend from the main body portion toward the tip, and clamp the buried pile; A chucking device characterized in that the chuck portion has a clamping surface that clamps and holds the buried pile.

6. The chucking device according to claim 5 , comprising three or more of the chuck portions.

7. a casing having a generally cylindrical hollow shape; a chucking device that is inserted into the casing and chucks the buried pile; The chucking device includes a main body having a generally cylindrical hollow shape capable of enclosing a buried pile therein; At least one pair of chuck portions are provided on the main body portion, extend from the main body portion toward the tip, and clamp the buried pile; a casing excavation step of excavating the casing into the ground so that the casing surrounds the buried pile; a chucking device inserting step of inserting a chucking device into the casing after the casing excavation step; After the chucking device inserting step, a chucking step of chucking the buried pile by the chucking device; After the chucking step, a pile extraction step is performed to pull up the chucked buried pile to the ground. A pile extraction system, comprising, after the pile extraction step, a casing extraction step of pulling the casing up to the ground.

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