JP2978436B2 - Existing pile removal method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an existing pile removing method, and more particularly to an existing pile removing method capable of efficiently removing an existing concrete pile buried underground as a foundation of an existing structure.

[0002]

2. Description of the Related Art In recent years, there has been an increasing number of works for dismantling and demolishing aging existing structures for the purpose of urban redevelopment and highly effective use of land. When dismantling a building frame, the ground part can be completely demolished using a concrete breaker or the like. On the other hand, the foundation portion supporting the above-ground portion usually does not conform to the load conditions of a newly constructed building or the like. Therefore, for example, when the position of an existing pile foundation (hereinafter referred to as an existing pile) interferes with the arrangement of a new foundation, the existing pile needs to be removed. In this case, it is necessary to grasp what kind of existing pile was used for the existing structure and to take a pile removal method suitable for the type of the existing pile.

[0003] Typical existing piles include a precast reinforced concrete pile (RC pile) and a precast prestressed concrete pile (PC pile) having a hollow annular cross section. In order to remove this kind of existing concrete ready-made piles, various pile removal methods have been conventionally developed. FIGS. 6A and 6B are schematic explanatory views showing one example of a conventional existing concrete pile removing method. FIG. 6A is a diagram showing an example of a vibro casing method. In this method, first, as shown in the figure, a steel pipe casing 52 is press-fitted into a ground 53 around an existing pile 50 using a vibro hammer 51 to cut off friction between the existing pile 50 and the surrounding ground 53 (friction). Cut). At this time, the soil 54 in the steel pipe casing 52 becomes dense due to the vibration compaction effect of the vibratory hammer 51. Thus, when the steel pipe casing 52 is pulled up, the existing pile 50 is also held and pulled out at the same time. FIG. 6B shows an example of a pile removal method in which the existing pile 50 is pulled out by a jack or the like after friction cutting by a water jet. In the construction method shown in the figure, while operating the water jet injection device 61 attached to the lower end of the sheet pile 62,
Pile the sheet pile 62 with a vibro hammer (not shown).
It is buried around 0. Therefore, the ground 53 around the existing pile 50 is loosened, and the existing pile 50 can be easily pulled out.

[0004]

However, in the pile removing method shown in each figure of FIG. 6, a vibro hammer is used to drive the steel pipe casing 52 and the sheet pile 62. As a result, considerable noise and vibration were generated, and the impact on buildings and residents around the site was large. Especially in urban areas
In some cases, this method cannot be used due to vibration regulations.
In the vibro-casing method shown in FIG. 6 (a), it is not possible to determine how long the steel pipe casing length should be set if the pile length of the existing pile is unknown. Furthermore, since the existing pile is held and pulled out, there is also a problem that residual soil is generated. On the other hand, in the construction method shown in FIG. 6B, the ground around the existing pile is loosened in a considerably wide range by the water jet injection. For this reason, it is necessary to consider the influence in the ridge design of the excavation work of the new structure. As a result, temporary costs are expected to increase.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to reduce noise and noise with a simple device.
Existing concrete piles buried underground are crushed in the ground without generating vibrations and disturbing the ground, and concrete crushed pieces and reinforcing steel wires and reinforcing steel wires of the piles can be collected on the ground. An object of the present invention is to provide an existing pile removal method and a pile crushing head used in the method.

[0006]

In order to achieve the above-mentioned object, the present invention relates to a concrete pile already buried in the ground, the outer diameter of which is smaller than the inner diameter of the hollow part of the existing concrete pile. A screw that expands in diameter from the tip to the root is formed in the shaft, the maximum diameter of the screw is substantially equal to the outer diameter of the existing pile , and the lead angle of the screw is
The auger screw of the earth auger to be mounted
Attach the shaft of the crushing head set to be two to three times the dovetail angle to the tip of the earth auger, and rotate the earth auger to lower the tip of the crushing head along the inner peripheral surface of the existing pile. Pressing in, the concrete of the existing pile is split from the inner peripheral surface of the upper end of the pile so as to be in a lump in a state of being connected by the reinforcing steel wire, and the existing pile is crushed over a predetermined range. The massive concrete crushed pieces entangled with the auger screw of the auger while being connected to the auger screw by the reinforcing steel wire are pulled up together with the auger screw and removed from the ground.

[0007] shaft portion in the vicinity of the head tip, a hydraulic drive concrete breaking mechanism is incorporated, the hydraulic drive Conch
The existing pile is split and crushed by driving the REIT crushing mechanism.
That it is preferable.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention for removing an existing pile will be described below with reference to the accompanying drawings. First, the configuration of the crushing head used in the existing pile removal method will be described with reference to FIG. FIG. 1 is a partial front view showing a tip portion of an auger screw 11 of an earth auger 10 mounted on a base machine B shown as an example in FIG. As shown in FIG. 1, a crushing head 20 as a head for crushing existing concrete piles of the present invention is attached to a lower end position of the auger screw 11 suspended along a leader (not shown) by a fixing pin (not shown). Have been. As a method of attaching the crushing head 20 to the lower end of the auger screw 11, a method using a fixing pin and a bolt and a nut is preferable from the viewpoint of efficiency of attachment / detachment work.
It may be attached by welding. In the present embodiment, two screws 22 are formed on the peripheral surface of the shaft portion 21 of the crushing head 20. The number of threads of the screw 22 formed in the shaft portion 21 is set in consideration of the concrete crushing force of the crushing head 20 and the ability to collect the ground crushed concrete crushed pieces entangled with the reinforcing steel wire on the ground. Is preferred. The dimensions of each part of the screw 22 are set to values corresponding to the dimensions of the existing concrete pile P to be crushed. That is, the inner diameter of the existing concrete pile P is φ
1. When the outer diameter is φ2, the diameter of the tip bit portion of the screw 22 of the crushing head 20 is φ3, and the maximum screw diameter is φ4, φ3 < φ4, φ3 < between the dimensions of the crushing head 20 and the existing concrete pile P. The relationship of φ1, φ2 = φ4 holds. In other words, these relationships are rephrased: (1) The screw shape of the crushing head is set to be a substantially frustoconical shape in which the envelope of the outer edge of the screw expands in diameter from the head end to the root. (2) The tip diameter of the crushing head shall be such that it can be inserted into the hollow part of the existing concrete pile. (3) The maximum diameter of the screw should be equal to the outer diameter of the existing concrete pile. Note that the maximum diameter of the screw in (3) and the outer diameter of the existing concrete pile may be substantially equal, and strict agreement is not required. Also, the maximum screw diameter φ4
It is preferable to set the outer diameter φ5 of the auger screw 11 to be substantially equal to or slightly smaller than the maximum screw diameter φ4.

Further, as shown in FIG. 1, the lead angle of the screw 22 formed in the crushing head 20 is set to be about two to three times larger than the lead angle of the auger screw 11. For this reason, the crushing head 20 is inserted into the hollow part 1 of the existing concrete pile P, and the auger screw 11
When a rotational force is applied to the crushing head 20 via the, a part of the rotational force is converted into a large forward force. The thickness of the steel plate used for the screw 22 is about three times as thick as the auger screw 11. Further, blades of various shapes are formed on the screw outer edge 22a as described later. When the crushing head 20 is advanced, the blade portion presses the inner peripheral surface 2 of the concrete pile P. The inner peripheral surface 2 of the concrete 3 against which the blade is pressed is crushed, and the tensile cracks generated by the applied internal pressure radially progress from the inner peripheral surface to the outside, thereby reinforcing the reinforcement arranged in the hoop direction. As the steel wire elongates, the entire concrete section is pulled.
Split by action .

Further, a guide rod 24 made of a steel rod is attached to the tip of the crushing head 20. In the present embodiment, the guide rod 24 is swingably attached to the tip cap 25 of the crushing head 20 via the support pin 26. Since the guide rod 24 is attached so that the tip 24a swings with a predetermined swing width, the guide rod tip 24a is simply fitted to the hollow portion 1 of the concrete pile P, and the tip of the auger screw 11, that is, the crushing head 20 is used. It can be reliably and easily guided to the hollow portion 1 of the concrete pile P. The guide rod 24
May be fixed to the tip cap 25 of the crushing head 20 by welding or the like.

Here, the shape of the blade portion of the screw outer edge 22a of the crushing head 20 will be described with reference to FIG.
FIG. 2A shows an example in which a clamp type carbide bit 27 is used as an outer edge blade portion. This carbide bit 27
A carbide tip (not shown) is incorporated in the cutting edge portion of. The carbide bit 27 is fitted into a holder formed on the screw outer edge 22a, and is fixed with a fixing bolt (not shown). According to this clamping method, the worn carbide bit 27 can be easily replaced. If the life of the bit is relatively long, the cemented carbide bit 27 can be fixed to the screw outer edge 22a by a welding method. FIG.
(B) shows an example in which a continuous saw blade-shaped blade portion 22b is directly formed on the screw outer edge 22a of the crushing head 20. In the crushing head 20 in which the blade portion 22b is formed, a large forward force is applied to the crushing head 20 by the action of crushing the inner peripheral surface of the concrete by the blade portion 22b. The action of pressing strongly toward the side is outstanding, thereby increasing the internal pressure effect and promoting the destruction of concrete. Therefore, the propulsive force of the auger screw 11 needs to be increased, but even if the blade portion is considerably worn, the crushing capacity of the crushing head 20 does not decrease so much. For this reason, there is an advantage that the replacement frequency of the blade portion can be reduced. Blade portion 22b formed on screw outer edge 22a
In addition to the shapes shown, the shape of the square tooth shape, curved wave shape, etc.
Various blade shapes are applicable. At this time, the maximum screw diameter φ4 may be the outer peripheral edge of the blade portion (the cutting edge of the carbide bit 27 or the continuous saw blade) provided on the screw outer edge 22a. 1 and 3, illustration of the blade portion is omitted for simplification of the drawing.

Next, the crushing mechanism of the pile by the crushing head 20 and the operation of collecting concrete crushed pieces by the earth auger will be described (see FIGS. 1 and 5). First, the head of the existing concrete pile P buried in the ground is exposed, and the leader 6 is set at the ground position so as to be aligned with the axis of the pile.
Set the direction and position of. Further, the auger screw 11 to which the crushing head 20 is attached at the tip is lowered to the pile head of the existing concrete pile P along a leader (not shown). At this time, the guide rod 24 is guided to the pile hollow portion 1, and the tip of the screw 22 of the crushing head 20 is brought into contact with the inner peripheral surface of the concrete pile. When the auger drive unit is driven from this state, the crushing head 20 at the tip end
Is given a rotational force via the auger screw 11,
The pile is advanced so as to be screwed into the hollow part 1 of the concrete pile. At this time, when the outer diameter of the screwed portion of the screw 22 becomes larger than the inner diameter of the hollow portion 1, the force transmitted from the screw acts as an internal pressure on the inner peripheral surface of the annular concrete. As a result, the concrete inner peripheral surface is crushed, and tensile cracks are generated radially from the inner peripheral surface to the outside due to the internal pressure effect. When the crushing head 20 further advances in the pile hollow portion 1, the screw diameter further increases, cracks completely penetrate inside and outside, and the annular concrete breaks into a plurality of blocks. At this time, a reinforcing steel wire or a PC steel wire is arranged in the concrete pile. It is expected that these reinforcing steel wires are deformed or partially stretched and fractured with the destruction of the surrounding concrete. However, in most cases, it is deformed while being buried in concrete crushed into blocks. As a result, the crushed concrete pieces that have been crushed are kept connected to such an extent that they are not separated from each other by these reinforcing steel materials.

As described above, according to the present invention, the existing concrete piles P can be crushed one after another from the top by moving the auger drive unit to advance the inside of the concrete pile hollow portion 1 while rotating the crushing head 20. it can. When the concrete pile is crushed, the auger screw 11 to which the crushing head 20 is attached is entangled with the axial reinforcing steel wire arranged in the concrete pile. A large number of strips and concrete fragments are connected to this reinforcing steel wire.
Most of the crushed concrete pieces are tangled around 1. In order to remove these reinforcing steel wires and concrete fragments from the auger screw 11, the auger screw 11 is rotated in the reverse direction while the auger screw 11 is entirely pulled up to the ground. At this time, a protruding scraper 9 is mounted in a sliding auger holder 8 provided at a predetermined position of a reader (not shown) (see FIG. 1). The scraper can scrape off the surface of the auger screw 11 to remove the reinforcing steel wire entangled with the auger screw 11.

FIG. 3 shows a concrete crushing mechanism which forms a pre-fracture portion on the inner surface of the concrete prior to concrete crushing by advancing with the rotation of the crushing head 20 so as to reduce the rotational force applied to the crushing head 20. It is explanatory drawing which showed the other embodiment incorporated. In the present embodiment, a steel pressing head 30 as a part of a concrete crushing mechanism is attached to the tip of the crushing head 20. As shown in the side view of FIG. 3 and the plan sectional view of FIG. 4 (a), the pressure head 30 has a cylindrical shape that is hollowed out in a substantially frustoconical shape with the inside opened upward, and has a substantially 120 ° angle. It is composed of pieces divided at equal angles. The upper end of each piece is swingably suspended from the crushing head 20. On the other hand, in the hollow shaft 21 of the crushing head 20, a lifting rod 31 is provided.
Is housed. A wedge cone 32 is fixed to the tip of the lifting rod 31. As shown in FIG. 3, the wedge cone 32 has a truncated conical shape substantially the same as the hollow portion of the pressure head 30, and a part of the wedge cone 32 is loosely fitted into the hollow portion of the pressure head 30. When the lifting rod 31 descends by a predetermined amount in the hollow shaft 21 by the hydraulic operation, the lower end of the pressure head 30 rotates outward as indicated by the arrow due to the spreading action of the wedge cone 32.

Therefore, as shown in FIGS. 4 (a) and 4 (b), the pressing head 30 is pushed outward by the wedge cone 32 being pushed into the hollow portion as shown in FIG. 4 (b). Can be spread. This pressing force causes the pressing head 30
The inner peripheral surface of the concrete that comes into contact with the concrete is crushed, and tensile cracks progress outward from that position. Thereafter, when the wedge cone 32 is raised, the pressure head 30 returns to the initial state shown in FIG. When the crushing head 20 is propelled from this state into the hollow portion 1 of the concrete pile, the concrete pile already having tensile cracks at various locations is easily broken into blocks. As means for pushing the pressure head 30 outward, a cylinder rod type,
Various known driving means such as an arm driving method can be applied. The dimensional relationship between each part of the screw 22 and the concrete pile P is the same as that shown in FIG.

Next, a method of crushing and removing the existing concrete pile P will be described with reference to FIG. FIG. 5 is a schematic explanatory view showing an operation state of crushing and removing an existing concrete pile buried underground by an earth auger 10 equipped with a crushing head 20 as a pile crushing head of the present invention. The inclined pile P1 shown in FIG. 5 is constructed as a foundation pile of a retaining wall (not shown) which has been removed, and the cast-in-place pile P2 to be constructed and the hatched portion 4 interfere with each other. In this example, a rough tee crane is used as the base machine B because of the slant pile P1. The rough tee crane can be set while running tires and holding the leader 6 of the earth auger 10 at the tip of the crane boom 5 so as to be inclined from the ground. Therefore, even in the case of the inclined pile P1, the reader 6 can be set accurately along the axis of the pile. Further, the crushing head 20 of the present invention is connected to the tip of the auger screw 11. The auger screw 11 is advanced to set the guide rod 24 (not shown) of the crushing head 20 in the hollow portion 1 of the pile head of the slant pile P1 so that the tip of the crushing head 20 coincides with the inner peripheral surface of the hollow portion 1 of the pile. . Further, the crushing head 20 is advanced while giving a rotational force to crush the slant pile P1 underground to a predetermined depth. Next, the auger screw 11 is pulled out while rotating in the reverse direction. At this time, the concrete crushed piece block connected with the muddy ground and the reinforcing steel wire is pulled up while being entangled with the auger screw 11. Further, the auger screw 11 is rotated in the reverse direction, passes through the sliding auger holder 8 of the leader 6, and the reinforcing steel wire and the concrete fragments are removed from the auger screw 11 by the internal scraper 9 (see FIG. 1). By the above operation, the existing concrete pile P1 buried in the ground can be completely removed over a predetermined range.

It is needless to say that a known device can be used for the auger drive unit 7, and any drive means of an electric motor or a hydraulic motor may be used.

[0018]

As is apparent from the above description, according to the present invention, the existing concrete pile P buried in the ground is crushed in the ground by a simple device, and the crushed pieces are efficiently collected. It has the effect of being able to do so. In addition, the removal of the existing piles does not disturb the surrounding buildings or residents at all and does not disturb the ground, so that it is expected that the construction of the new underground part is not hindered at all.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a pile crushing head used in the present invention.

FIG. 2 is a partial front view showing one mode of a blade portion of a screw outer edge of the crushing head.

FIG. 3 is a partial front view showing another embodiment in which a concrete crushing mechanism is provided at the tip of a crushing head.

FIG. 4 is a sectional view showing a concrete crushing mechanism by the concrete crushing mechanism shown in FIG. 3;

FIG. 5 is a work state explanatory view showing a work state of removing an existing concrete pile.

FIG. 6 is a construction state diagram showing one example of a conventional existing concrete pile removal method.

[Explanation of symbols]

 Reference Signs List 1 hollow part of concrete pile 2 inner peripheral surface of concrete pile 10 earth auger 11 auger screw 20 crushing head 22 screw 24 guide rod 30 concrete crushing mechanism P, P1 Existing concrete pile

Claims (2)

(57) [Claims] A screw is formed on a shaft of an existing concrete pile embedded in the ground, the outer diameter of the tip being smaller than the inner diameter of the hollow part of the existing concrete pile, and the diameter being increased from the tip to the root. , The maximum diameter of the screw is substantially equal to the outer diameter of the existing pile, the lead angle of the screw,
The auger screw of the earth auger to be mounted
A crushing head set to be two to three times the de-angle is attached to the tip of the earth auger, and the tip of the crushing head is press-fitted along the inner peripheral surface of the existing pile by a rotating and lowering operation of the earth auger. Then, the concrete of the existing pile is split from the inner peripheral surface of the upper end of the pile so as to be clumped in a state where the concrete is connected by the reinforcing steel wire, and the existing pile is crushed over a predetermined range. An existing pile removing method, characterized in that massive concrete crushed pieces entangled in a state of being connected to a screw by the reinforcing steel wire are removed together with the auger screw from the ground. To 2. A shaft portion in the vicinity of the head tip, a hydraulic drive concrete breaking mechanism is incorporated, the hydraulic drive Conch
The existing pile is split and crushed by driving the REIT crushing mechanism.
Existing pile removal method according to claim 1, characterized in that the so that.