Methods and systems for removing existing piles

Abstract

This invention provides a method and system for removing existing piles that enables the removal of existing piles even in construction areas with headroom restrictions or in confined construction areas, and enables the removal of existing piles even if they are deeply embedded. It also eliminates the need to remove the attached soil from the existing piles after they have been pulled out to the surface. [Solution] The method for removing existing piles includes an isolation step in which a spray rod 35 is inserted into the ground surrounding the existing pile 10 and a high-pressure fluid is sprayed from the spray rod 35 toward the existing pile 10 to isolate the entire circumference or most of the existing pile 10 from the surrounding ground, and a removal step in which the existing pile 10 is pulled out to a predetermined height and the upper part is removed, and this pulling out and partial removal is repeated to remove the existing pile 10.

Description

Technical Field

[0001] The present invention relates to a method and a system for removing existing piles.

Background Art

[0002] When constructing a new underground structure such as a shield tunnel, if there are existing piles in the construction area, it is necessary to remove the existing piles that will hinder the construction of the underground structure. A heavy machine installed on the ground is applied to remove the existing piles. For example, a full-rotation type (full-turn type) all-casing method is generally applied, in which a full-turn boring machine is placed on the ground, and while rotating and pressing the casing tube with strong high torque, the earth and sand and the existing pile in the casing tube are discharged with a hammer grab or the like. Since the stationary full-turn boring machine applied in this method is generally large in scale, there may be cases where it cannot be applied in a construction area with a headroom limit or a narrow construction area. Currently, although a full-turn boring machine under a low headroom condition of about 4 m has been developed and applied, even when this type of full-turn boring machine is applied, there is an actual situation that it is often difficult to move in and out and operate a heavy machine in a working environment where elevated columns exist under an elevated structure. Therefore, although it becomes possible to move in and out under an elevated structure by using a BG boring machine (leader type casing rotary boring machine) with a low-profile specification, for example, when the length of the existing pile to be removed is as long as about 10 m and the removal depth is 10 m or more, it becomes extremely difficult to remove the existing pile.

[0003] From the above, there is a need for a method and a system for removing existing piles that can efficiently remove existing piles even when removing existing piles with a deep embedding depth in a construction area with a headroom limit or a narrow construction area.

[0004] Here, Patent Document 1 proposes a method for removing existing piles. This removal method involves inserting a jet rod equipped with an ultra-high pressure water nozzle at its tip into the ground around the existing pile to be removed, and repeatedly cutting the ground in a panel-like manner by jetting ultra-high pressure water during the penetration or withdrawal process, thereby forming a polygonal edge-cutting surface that surrounds the entire circumference or most of the existing pile, after which the existing pile is pulled out and removed. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2004-218378 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In the method for removing existing piles described in Patent Document 1, a wide, panel-like separation surface is formed in the ground surrounding the existing pile to be removed, but at a distance from the pile itself. As a result, the existing pile is pulled out with a large amount of ground attached to it. Therefore, after the existing pile is pulled up to the surface, it is necessary to remove the attached ground by scraping or other means. This work is very time-consuming, and there is also the problem of needing to secure work space in the aforementioned narrow construction area to remove the ground attached to the existing pile in this way.

[0007] The present invention aims to provide a method and system for removing existing piles that enables the removal of existing piles even in construction areas with headroom restrictions or in narrow construction areas, enables removal even when the existing piles to be removed are deeply embedded, and further eliminates the need to remove the adhering soil from the existing piles after they have been pulled out to the surface. [Means for solving the problem]

[0008] To achieve the above objective, one aspect of the method for removing existing piles according to the present invention is: A separation step is performed by inserting a spray rod into the ground surrounding the existing pile and injecting a high-pressure fluid from the spray rod toward the existing pile, thereby separating the entire circumference or most of the existing pile from the surrounding ground. The method is characterized by having a removal step in which the existing pile is pulled out to a predetermined height and the upper part is removed, and this pulling out and partial removal is repeated to remove the existing pile.

[0009] According to this embodiment, a high-pressure fluid is injected from an injection rod inserted into the surrounding ground of the existing pile toward the existing pile to sever the entire circumference or most of the existing pile from the surrounding ground (cutting circumferential friction), after which the existing pile is pulled out to a predetermined height, the upper part is removed, and this pulling out and partial removal is repeated to remove the entire existing pile. This makes it possible to remove existing piles even in construction areas with headroom restrictions or in narrow construction areas, and also makes it possible to remove existing piles even if they are deeply embedded. Furthermore, in the separation process, high-pressure fluid is directly injected onto the existing piles, washing away the soil adhering to the existing piles during the separation stage before the piles are pulled out to the ground. This eliminates the need to remove the adhering soil after the existing piles have been pulled out to the ground. In this way, washing away the adhering soil prior to the extraction of the existing piles reduces the extraction load compared to when the existing piles are extracted with the soil still attached, thereby reducing the load on the heavy machinery.

[0010] The "predetermined height" for pulling out existing piles in a single operation can be set to a height at which the removal system can pull out the piles under headroom restrictions, for example, within a range of about 1m to 2m. Furthermore, since only a short length of the existing piles, which have been isolated from the surrounding ground, are pulled out, it becomes possible to carry out the work with a small removal system. For example, even when removing existing piles located close to railway lines, the removal work can be carried out without removing railway protection fences or other structures that form the boundary of the railway line.

[0011] Furthermore, in another embodiment of the method for removing existing piles according to the present invention, The aforementioned separation process is characterized by injecting a high-pressure fluid onto the existing pile while swinging the injection rod from side to side.

[0012] According to this embodiment, by injecting high-pressure fluid onto the existing pile while swinging the injection rod from side to side, the high-pressure fluid can be efficiently injected over a wide area of ​​the existing pile, thereby improving the efficiency of separating the existing pile from the surrounding ground.

[0013] Furthermore, in another embodiment of the method for removing existing piles according to the present invention, The aforementioned separation process is characterized by sequentially or simultaneously inserting the injection rods into multiple locations in the ground surrounding the existing pile, and injecting high-pressure fluid toward the existing pile from multiple locations.

[0014] According to this embodiment, by injecting high-pressure fluid from multiple locations in the surrounding ground toward the existing pile, effective isolation of the entire existing pile from the surrounding ground can be achieved, enabling smooth extraction of the existing pile. In this embodiment, one injection rod may be inserted sequentially into multiple locations, or multiple injection rods may be inserted and high-pressure fluid may be injected simultaneously into existing piles.

[0015] Furthermore, other embodiments of the method for removing existing piles according to the present invention include: The high-pressure fluid is characterized in that it is a bentonite stabilizing fluid.

[0016] According to this embodiment, since the high-pressure fluid is a bentonite stabilizing fluid, the solidification of the high-pressure fluid after injection is prevented, while the hole wall of the surrounding ground, which is isolated from the existing pile, is protected by the bentonite stabilizing fluid, thereby preventing its collapse.

[0017] Furthermore, in another embodiment of the method for removing existing piles according to the present invention, The removal process is characterized by installing a gantry-type frame equipped with jacks on the ground at a position that straddles the existing pile in a plan view, installing an extraction jig equipped with a coupler on the top of the existing pile, and attaching a wire or PC steel rod hanging from the jack to the coupler to pull it out to a predetermined height.

[0018] According to this aspect, a wire or PC steel bar hanging down from a gantry equipped with a jack at a position straddling an existing pile is attached to a coupler provided at the head of the existing pile, and the existing pile is pulled out. Thus, the existing pile can be stably pulled out even under the headroom restriction. Here, the number of jacks may be one or more. Also, since a larger pulling force is required in the initial stage of completely severing the adhesion state with the surrounding ground, for example, four jacks are used in this initial stage, and during subsequent repeated pulling, the number and specifications of the jacks may be changed, such as reducing the number of jacks to two in the middle stage of construction.

[0019] Also, in another aspect of the method for removing an existing pile according to the present invention, in the removal process, after pulling out the existing pile to a predetermined height, a receiving jig is attached around the existing pile, a temporary support gantry is installed around the existing pile, and the upper part of the existing pile is removed while the receiving jig is temporarily supported by the temporary support gantry.

[0020] According to this aspect, after pulling out the existing pile to a predetermined height, a receiving jig is attached around the existing pile, a temporary support gantry is installed around the existing pile, and the upper part of the existing pile is removed while the receiving jig is temporarily supported by the temporary support gantry. Thus, the existing pile can be cut and removed at a desired cutting position while maintaining the existing pile in a stable posture.

[0021] Also, in another aspect of the method for removing an existing pile according to the present invention, in the removal process, the cut piece of the existing pile is horizontally pulled and carried out by a gear trolley equipped on the gantry.

[0022] According to this aspect, by horizontally pulling and carrying out the cut piece of the existing pile by a gear trolley equipped on the gantry, it becomes possible to quickly carry out the cut piece of the existing pile within a limited space.

[0023] Also, one aspect of the system for removing an existing pile according to the present invention is A high-pressure injection device comprising an injection rod inserted into the surrounding ground of the existing pile and injecting high-pressure fluid toward the existing pile, and a base machine for inserting the injection rod into the surrounding ground, It has a gantry-type frame installed on the ground, positioned to straddle the existing piles in a plan view, and equipped with jacks, A wire or PC steel rod suspended from the jack is directly or indirectly attached to the existing pile, and the existing pile is pulled up to a predetermined height by the jack and the upper part is removed, and this pulling up and partial removal is repeated until the existing pile is removed.

[0024] According to this embodiment, by injecting a high-pressure fluid from an injection rod inserted into the ground surrounding the existing pile toward the existing pile to isolate the entire circumference or most of the existing pile from the surrounding ground, the existing pile is pulled out to a predetermined height, the upper part is removed, and this pulling out and partial removal is repeated to remove the entire existing pile, it becomes possible to remove existing piles even in construction areas with headroom restrictions or narrow construction areas, and it is also possible to remove existing piles even if they are deeply embedded. Furthermore, by directly injecting a high-pressure fluid toward the existing pile, the ground adhering to the existing pile is washed away at the isolation stage before the existing pile is pulled out to the surface, thus eliminating the need to remove the adhering ground from the existing pile after it has been pulled out to the surface. [Effects of the Invention]

[0025] According to the method and system for removing existing piles of the present invention, it is possible to remove existing piles even in construction areas with headroom restrictions or in narrow construction areas, and it is also possible to remove existing piles even if they are deeply embedded. Furthermore, it eliminates the need to remove the attached ground from the existing piles after they have been pulled out to the surface. [Brief explanation of the drawing]

[0026] [Figure 1] This is a process diagram of an example of a method for removing existing piles according to the embodiment. [Figure 2] Following Figure 1, the next diagram shows an example of a method for removing existing piles according to the embodiment. [Figure 3] Following Figure 2, the next diagram shows an example of a method for removing existing piles according to the embodiment. [Figure 4] Following Figure 3 is a process diagram illustrating an example of a method for removing existing piles according to the embodiment. [Figure 5] Following Figure 4, this is a process diagram illustrating an example of a method for removing existing piles according to the embodiment. [Figure 6] Following Figure 5, this is a process diagram of an example of a method for removing existing piles according to the embodiment, and shows the existing pile removal system according to the embodiment. [Figure 7] Following Figure 6, the next diagram shows an example of a method for removing existing piles according to the embodiment. [Figure 8] Following Figure 7 is a process diagram illustrating an example of a method for removing existing piles according to the embodiment. [Figure 9] Following Figure 8, the next diagram shows an example of a method for removing existing piles according to the embodiment. [Figure 10] Following Figure 9 is a process diagram illustrating an example of a method for removing existing piles according to the embodiment. [Figure 11] Following Figure 10 is a process diagram illustrating an example of a method for removing existing piles according to the embodiment. [Figure 12] Following Figure 11, the next diagram shows an example of a method for removing existing piles according to the embodiment. [Figure 13] Following Figure 12 is a process diagram illustrating an example of a method for removing existing piles according to the embodiment. [Figure 14] Following Figure 13, the next diagram shows an example of a method for removing existing piles according to the embodiment. [Modes for carrying out the invention]

[0027] The removal method and removal system for existing piles according to the embodiment will be described below with reference to the attached drawings. In this specification and drawings, substantially identical components may be denoted by the same reference numerals to avoid redundant explanations.

[0028] [Method and system for removing existing piles according to an embodiment] An example of a method for removing existing piles and a removal system according to the embodiment will be described with reference to Figures 1 to 14. Here, Figures 1 to 14 are, in order, process diagrams of an example of a method for removing existing piles according to the embodiment. Note that, since multiple components of the removal system according to the embodiment are changed during the removal method process, not all components of the removal system are shown in a single figure. Therefore, the components of the removal system will be explained each time the removal method is described.

[0029] The construction area in the illustrated example is close to the railway line T, and a retaining wall P made of sheet piles is constructed behind the boundary wall B that forms the boundary with the adjacent property. Existing piles 10 (see Figure 9), which are to be removed, are buried in the ground behind boundary wall B. In addition, although not shown in the illustration, in addition to being along the railway line T, there are elevated bridges and other structures overhead, and there is a headroom restriction that limits the workable area to a height of approximately 4m above the ground surface S. Furthermore, the groundwater level is high, close to the ground surface, which is a challenging construction condition.

[0030] For example, when constructing a shield tunnel or the like below railway T, existing piles 10 located along railway T become an obstacle to tunnel construction. Therefore, the existing piles 10 are to be removed under harsh construction conditions, such as being located along a railway line, having headroom restrictions, and having a high groundwater level.

[0031] The existing pile 10 in the illustrated example is a steel pile such as an H-shaped steel, with its pile head located about 1m to 2m below the ground surface S, and its length being 10m or more, so that its lower end extends to about 13m to 15m below the ground surface S. As shown in Figure 1, when extracting the existing pile 10, the ground around the pile head of the existing pile 10 is excavated and a surface casing C is installed, and a pile head extraction pipe 15 (an example of an extraction jig) is attached to the exposed pile head. The pile head extraction pipe 15 in the illustrated example has four couplers 17 attached to its outer circumference at 90-degree intervals.

[0032] A pair of support legs 22 are installed at a position that straddles the surface casing C, forming a gantry-type support frame 20 (see Figure 6). The support legs 22 are formed by laying out multiple H-shaped steel beams or other shaped steel materials or square steel pipes, then erecting multiple H-shaped steel beams or other shaped steel materials or square steel pipes, and then joining the entire structure together by welding or bolting.

[0033] First, the separation process of the removal method will be explained in detail. In this removal method, as shown in Figures 2 and 3, a stage 38 is installed between a pair of support legs 22, and a high-pressure spray device 30 is placed on the stage 38.

[0034] The high-pressure injection device 30 comprises a base machine 32 and an injection rod 35. The base machine 32 pre-drills around the existing pile 10 with a casing (not shown), then the injection rod 35 is erected around the existing pile 10, and high-pressure fluid is directly injected onto the existing pile 10 from an injection hole (not shown) located below the injection rod 35, thereby isolating the existing pile 10 from the surrounding ground.

[0035] More specifically, injection rods 35 are sequentially inserted into multiple locations (three locations in the illustrated example) in the ground surrounding the existing pile 10, and high-pressure fluid is directly injected from these multiple locations toward the existing pile 10.

[0036] By directly injecting high-pressure fluid from the injection rod 35 onto the existing pile 10, it is possible to wash away the ground adhering to the circumferential surface of the existing pile 10 while simultaneously separating it from the surrounding ground.

[0037] Here, a bentonite stabilizing fluid is applied as the high-pressure fluid directly injected into the existing pile 10. By applying the bentonite stabilizing fluid, the borehole wall can be protected. Furthermore, since the bentonite stabilizing fluid does not solidify until the existing pile 10 is completely removed, there is no risk of it hindering the removal of the existing pile 10. If the surrounding ground is relatively hard and the stability of the borehole wall is maintained, tap water or other water may be applied as the high-pressure fluid.

[0038] As shown in Figure 3, the injection rod 35 is inserted at the first injection position around the existing pile 10, and the bentonite stabilizing liquid is injected into the existing pile 10 in the X2 direction while the injection rod 35 is swung from side to side in the X1 direction.

[0039] In this way, by swinging the injection rod 35 from side to side and directly injecting the bentonite stabilizing fluid toward the existing pile 10, the bentonite stabilizing fluid can be efficiently injected over a wide area of ​​the existing pile 10. Furthermore, even if the existing pile 10 has an uneven outer shape such as an H-shaped steel, the bentonite stabilizing fluid can be injected into the details (the boundary between the web and the flange), and the adhering ground can be effectively washed away over the entire circumferential surface of the existing pile 10.

[0040] The injection rod 35 is inserted into the lower end of the borehole and, while oscillating, injects bentonite stabilizing fluid onto the existing pile 10. This process is repeated as the rod is pulled upward, thereby washing away the soil adhering to the outer perimeter of the existing pile 10 within a predetermined range in plan view (in the illustrated example, a 120-degree range opposite the operating injection rod 35 in plan view) and separating it from the surrounding soil.

[0041] Next, the injection rod 35, which had been raised to the ground, was moved to the second injection position shown in Figure 4. The injection rod 35 was inserted into the lower end of the borehole, and while swinging in the X1 direction, bentonite stabilizing fluid was injected into the existing pile 10 in the X2 direction. This process was repeated while raising the injection rod 35 upwards, thereby washing away the soil adhering to the outer perimeter of the existing pile 10 within a predetermined range in plan view (in the illustrated example, the lateral range of the first 120-degree range on the side of the operating injection rod 35 in plan view), and separating it from the surrounding ground.

[0042] Next, the injection rod 35, which had been pulled up to the ground, was moved to the third injection position shown in Figure 5. The injection rod 35 was inserted into the lower end of the borehole, and while swinging in the X1 direction, bentonite stabilizing fluid was injected into the existing pile 10 in the X2 direction. This process was repeated while pulling the injection rod 35 upward, so that the ground adhering to the outer perimeter of the existing pile 10 was washed away and separated from the surrounding ground in a predetermined area of ​​the existing pile 10 in a plan view (in the illustrated example, in a plan view, the lateral area of ​​the 120-degree range on the side of the operating injection rod 35, covering the first and second 120-degree ranges).

[0043] In this way, by sequentially inserting the injection rods 35 at three locations around the existing pile 10 and washing away the ground adhering to the entire circumference of the existing pile 10 with high-pressure bentonite stabilizing fluid, it is possible to isolate the entire circumference or most of the existing pile 10 from the surrounding ground.

[0044] Furthermore, in this way, the adhering ground around the outer perimeter of the existing pile 10 is washed away during the process of separating the existing pile 10 from the surrounding ground, eliminating the need to remove the adhering ground after the existing pile 10 is pulled out to the surface. This is advantageous in construction sites where there are headroom restrictions and limitations on the planar construction space, and therefore it is difficult to secure space to remove the adhering ground on the surface using methods such as scraping.

[0045] Here, the illustrated example shows a configuration in which injection rods 35 are sequentially inserted into three locations around the existing pile 10 and bentonite stabilizing fluid is injected. However, if it is possible to isolate the pile from the surrounding ground by inserting the injection rod 35 into only one location, then insertion into only one location is acceptable. Alternatively, insertion into two locations or four or more locations is also possible. Furthermore, instead of the illustrated example, a construction method may be used in which multiple injection rods 35 are inserted into the ground simultaneously and pulled up while simultaneously injecting bentonite stabilizing fluid (this is the isolation process).

[0046] Furthermore, the stage 38 and the high-pressure spray device 30 installed on it are components of the removal system 100 according to this embodiment.

[0047] Next, the removal process will be explained in detail with reference to Figures 6 through 14.

[0048] After the edge separation process is completed, the high-pressure injection device 30, including the stage 38, is removed, an upper jack base 25 is horizontally placed on the upper ends of a pair of support legs 22, and two center-hole jacks 28A (an example of a jack) are installed on the upper jack base 25. In addition, main girders made of multiple H-shaped steel or other shaped steel materials are placed across the surface casing C, and a pair of horizontal members made of shaped steel materials are placed on top of the multiple main girders to form a lower jack base 27, and two additional center-hole jacks 28B (another example of a jack) are installed on the lower jack base 27.

[0049] In this way, a pair of support legs 22, upper jack bases 25 mounted on them, and lower jack bases 27 installed below them form a gantry-type support structure 20 that straddles the existing piles 10 (and pile head extraction pipes 15) located inside the surface casing C.

[0050] The two upper jacks 28A and the two lower jacks 28B are positioned at 90-degree intervals in a plan view. The lower ends of the four PC steel rods 29A and 29B hanging from each of the jacks 28A and 28B are connected to four couplers 17 attached at 90-degree intervals around the outer circumference of the pile head extraction pipe 15. Wire may be used instead of PC steel rods.

[0051] As shown in Figure 7, four jacks 28 are operated synchronously, and the pile head extraction pipe 15 and the existing pile 10 connected to it are pulled upward in the Y1 direction using four PC steel rods 29. Although the existing pile 10 is isolated from the surrounding ground during the isolation process, the lower end of the existing pile 10 is in close contact with the surrounding ground. Therefore, when initially pulling out the existing pile 10, a certain amount of pulling force is required to isolate it from the ground. Thus, in the illustrated example, all four jacks 28 are operated to pull out the existing pile 10.

[0052] As described above, since there is a headroom restriction at the construction site shown in the illustration, the height of a single extraction (prescribed height) is set to a range of approximately 1m to 2m.

[0053] After the ground excavation between the existing pile 10 and the surrounding ground is complete, the pulling force (lifting force) used during the ground excavation is no longer required when pulling out the existing pile 10. Therefore, as shown in Figure 8, the lower jack base 27, which is equipped with two jacks 28B, is removed, and the existing pile 10 is pulled upward in the Y2 direction to a predetermined height using only the two jacks 28A installed on the upper jack base 25.

[0054] As shown in Figure 9, by further pulling out the pile head extraction pipe 15 and the head of the existing pile 10 upward in the Y3 direction, a portion of the pile head extraction pipe 15 and the existing pile 10 is exposed above the ground surface S.

[0055] Next, as shown in Figure 10, a pair of main girders 42 made of H-shaped steel or other shaped steel are placed around the existing pile 10 exposed above the ground surface S, straddling the surface casing C. A pair of horizontal girders 44 made of H-shaped steel or other shaped steel are placed over the pair of main girders 42 around the existing pile 10, and the main girders 42 and horizontal girders 44 are joined together with bolts, vises, etc., to form a temporary support frame 40.

[0056] Meanwhile, on the outer circumference above the existing pile 10 exposed above the ground surface S, support jigs 18 and couplers 17 are attached by welding or other means to positions corresponding to a pair of main girders 42 and a pair of horizontal girders 44, respectively. By, for example, jacking down, the support jigs 18 and couplers 17 are temporarily supported by the main girders 42 and horizontal girders 44, respectively. As a result, the pile head extraction pipe 15 and the existing pile 10 are temporarily supported by the temporary support frame 40.

[0057] As shown in Figure 11, the head of the existing pile 10 is cut in a stable temporary support position, and the pile head extraction pipe 15 and the cut piece 10' of the existing pile 10 are pulled upward in the Y4 direction using a PC steel bar 29A. A gear trolley 26 is mounted on the upper jack base 25 so as to be able to slide laterally.

[0058] As shown in Figure 12, the pile head extraction pipe 15 and the cut piece 10' that have been pulled up are transferred to the gear trolley 26, and the gear trolley 26 is transported laterally along the upper jack base 25 in the Y6 direction.

[0059] As shown in Figure 13, the transported pile head extraction pipe 15 and cut pieces 10' are laid on their sides in the Y7 direction next to the gantry frame 20, and the pile head extraction pipe 15 and cut pieces 10' are transported out of the site in the Y8 direction by trucks or trailers (not shown).

[0060] As shown in Figure 14, two PC steel rods 29A hanging from two jacks 28A are attached to two couplers 17 attached to the existing pile 10, respectively. In the same manner as previously described, the jacks 28A are operated to raise the existing pile 10 to a predetermined height (approximately 1m to 2m), a support jig 18 and couplers 17 are attached to the upper outer circumference of the existing pile 10 by welding or other means, and the jacks are lowered to create a stable position for cutting the existing pile 10, thereby cutting the upper part of the existing pile 10.

[0061] The cut pieces 10', formed by cutting off the upper part of the existing pile 10, are transferred to a gear trolley 26, transported to the side of the gantry frame 20, and then laid on their side and removed from the site.

[0062] By repeating the same method thereafter, the entire existing pile 10 will be completely removed (end of removal process).

[0063] Furthermore, the gantry-type frame 20 and the temporary support frame 40 are components of the removal system 100 according to this embodiment.

[0064] According to the removal method using the illustrated removal system 100, a high-pressure fluid is injected from an injection rod 35 inserted into the surrounding ground of the existing pile 10 toward the existing pile 10 to isolate the entire circumference or most of the existing pile 10 from the surrounding ground. After that, the existing pile 10 is pulled out to a predetermined height, and the upper part is removed. This pulling out and partial removal is repeated until the entire existing pile 10 is removed. This makes it possible to remove the existing pile 10 even in construction areas with headroom restrictions or in narrow construction areas, and it is also possible to remove the existing pile 10 even when the embedding depth of the existing pile 10 to be removed is deep, such as 10m or more as shown in the illustrated example.

[0065] Furthermore, in the separation process, high-pressure fluid is directly injected onto the existing pile 10, so the ground adhering to the existing pile 10 is washed away at the separation stage before the existing pile 10 is pulled out to the ground. This eliminates the need to remove the adhering ground after the existing pile 10 has been pulled out to the ground.

[0066] Furthermore, the height at which the existing pile 10 is pulled out in a single operation can be set to a height at which the removal system 100 can pull it out under headroom restrictions, for example, within a range of about 1m to 2m. In addition, since the existing pile 10, which has been isolated from the surrounding ground, is pulled out by only a short length, it becomes possible to perform the work with a relatively low-power jack 28, and in the case of removing an existing pile 10 located close to an operating railway line as shown in the illustrated example, the removal work of the existing pile 10 can be performed without removing the railway protection fence or the like that forms the boundary of the railway line.

[0067] Furthermore, other embodiments may be used in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited in any way to the configurations shown herein. In this regard, modifications can be made without departing from the spirit of the present invention, and can be appropriately determined according to the application form. [Explanation of Symbols]

[0068] 10: Existing piles 10': Cut piece 15: Pile head extraction pipe (extraction jig) 17: Coupler 18: Receiving jig 20: Gantry frame 22: Frame legs 25: Upper jack stand 26: Gear Trolley 27: Lower jack stand 28, 28A, 28B: Jack (Center Hole Jack) 29,29A,29B:PC steel bar 30: High-pressure injection device 32: Base Machine 35: Injection Rod 38: Stage 40: Temporary support frame 42: Main digit 44: Horizontal girder 100: Removal system (system for removing existing piles) S: Ground surface T: Railway B: Boundary wall of adjacent property P: Retaining wall (sheet pile) C: Surface casing

Claims

1. A method for removing existing piles, A separation step is performed by inserting a spray rod into the ground surrounding the existing pile and injecting a high-pressure fluid from the spray rod toward the existing pile, thereby separating the entire circumference or most of the existing pile from the surrounding ground. A method for removing an existing pile, characterized by comprising a removal step of pulling out the existing pile to a predetermined height and removing the upper part thereof, and repeating this pulling out and partial removal to remove the existing pile.

2. The method for removing an existing pile according to claim 1, characterized in that, in the edge-cutting step, high-pressure fluid is injected onto the existing pile while swinging the injection rod from side to side.

3. The method for removing an existing pile according to claim 2, characterized in that, in the separation step, the injection rods are inserted sequentially or simultaneously into multiple locations in the ground surrounding the existing pile, and a high-pressure fluid is injected from the multiple locations toward the existing pile.

4. The method for removing existing piles according to claim 1, characterized in that the high-pressure fluid is a bentonite stabilizing fluid.

5. The removal process is characterized in that, on the ground, a gantry frame equipped with a jack is installed at a position that straddles the existing pile in a plan view, a pulling jig equipped with a coupler is installed on the top of the existing pile, and a wire or PC steel rod hanging from the jack is attached to the coupler and pulled up to a predetermined height, as described in claim 2.

6. The method for removing an existing pile according to claim 5, characterized in that, in the removal step, after pulling out the existing pile to a predetermined height, a support jig is attached around the existing pile, a temporary support frame is installed around the existing pile, and the upper part of the existing pile is removed while the support jig is temporarily supported by the temporary support frame.

7. The method for removing an existing pile according to claim 6, characterized in that, in the removal step, the cut pieces of the existing pile are horizontally pulled out by a gear trolley equipped on the gantry frame.

8. This is a system for removing existing piles. A high-pressure injection device comprising an injection rod inserted into the surrounding ground of the existing pile and injecting high-pressure fluid toward the existing pile, and a base machine for inserting the injection rod into the surrounding ground, It has a gantry-type frame installed on the ground, positioned to straddle the existing piles in a plan view, and equipped with jacks, A system for removing existing piles, characterized in that a wire or PC steel rod suspended from the jack is directly or indirectly attached to the existing pile, the jack pulls the existing pile up to a predetermined height and removes the upper part thereof, and this pulling up and partial removal is repeated until the existing pile is removed.

Images