JP2004131923A - Extracting method for existing underground structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extracting method for extracting an existing structure from a ground with excellent construction efficiency and at a low cost. <P>SOLUTION: A casing 2 is rotatingly propelled against the ground 5. When the lowermost end of the casing 2 reaches a depth deeper than the lowermost end of the existing structure 3, the rotating propulsion of the casing 2 is stopped. A cutting hole 7 extending from the uppermost end to the lowermost end of the existing structure 3 is formed in the existing structure 3 so as to pass the center axis of the exiting structure 3. After a jet pump 9 is connected to the uppermost end of the cutting hole 7, high-pressure water is fed from the jet pump 9 toward the cutting hole 7. By this, water is fed into the casing 2, and the existing structure 3 is suspended in an immersed state in the casing. A buoyancy acts on the existing structure 3. With the buoyancy acting on the existing structure 3, the existing structure 3 is lifted and extracted from the ground 5. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a drawing method for pulling an existing structure buried underground from the ground.
[0002]
[Prior art]
When building and constructing various structures, it is necessary to improve the ground. As part of this, concrete structures such as concrete piles, steel structures such as steel piles, wooden structures such as wooden piles, and other structures buried or remaining deep underground (hereinafter, these A pull-out operation is performed to pull out the structures (collectively, “existing structures”). Conventionally, this drawing operation has been performed as follows. First, a casing (steel pipe) is inserted so as to surround the existing structure, and soil and sand between the casing and the existing structure are removed. Then, the existing structure is lifted by a heavy machine such as a crane to pull out the existing structure.
[0003]
[Problems to be solved by the invention]
However, in the conventional method, since the existing structure is pulled out using only the lifting force of the heavy machinery, the lifting capacity required for the heavy machinery also increases with the enlargement of the existing structure, Large heavy machinery is required. As a result, there is much room for improvement in terms of construction efficiency and construction cost.
[0004]
The present invention has been made in view of the above problems, and has as its object to provide a drawing method for pulling out an existing structure from the ground with excellent construction efficiency and at low cost.
[0005]
[Means for Solving the Problems]
The present invention is a drawing method for pulling out an existing structure buried underground, in order to achieve the above object, a first step of forming a hole in the existing structure that is connected to the lowermost end of the existing structure, A second step of supplying water to the lowermost end of the existing structure through a borehole to give buoyancy to the existing structure, and a step of providing buoyancy to the existing structure while maintaining the existing structure with buoyancy And a third step of lifting
[0006]
In the invention configured as described above, after a drilling hole connected to the lowermost end of the existing structure is formed in the existing structure, water is supplied to the lowermost end of the existing structure through the drilling. As a result, part of the water discharged from the lowermost end of the existing structure flows to the ground surface side along the outer peripheral side surface of the existing structure, and buoyancy acts on the existing structure due to the presence of the water. Then, the existing structure is lifted in a state where the buoyancy acts, and the existing structure is pulled out from the ground. By using the buoyancy in this way, it is possible to reduce the lifting force required for pulling out the existing structure.
[0007]
Here, before water is supplied toward the lowermost end of the existing structure, the casing is previously rotationally propelled to the ground so as to surround the existing structure, and the front end of the casing is set to a depth equal to or more than the lowermost end of the existing structure. It may be configured to reach the height. In this case, when water is supplied toward the lowermost end of the existing structure, the ground (such as earth and sand) located below the lowermost end of the existing structure is flushed by the water supply, and the inside of the casing is filled with water. That is, the existing structure exists in the casing in which the water is stored, and buoyancy acts on the existing structure. In this way, water discharged from the lowermost end of the existing structure efficiently flows through the casing, and buoyancy can be reliably given to the existing structure with a small amount of water.
[0008]
Further, when the plurality of steel pieces are positioned below the lowermost end of the existing structure before the second step, water discharged from the lowermost end of the existing structure is effectively prevented from permeating into the ground. In addition, the water use efficiency can be further improved. Also, without using a plurality of steel slabs, if the water pressure at the time of water supply is increased in order to increase construction efficiency, the ground located below the lowermost end of the existing structure will be dug deeper, as described above. By providing a plurality of steel slabs, it is possible to prevent the ground from being dug down by the water that has been pumped.
[0009]
Further, an auxiliary member is attached to the existing structure at a position above the ground surface, and when the existing structure is pulled out (third step), the auxiliary member is pushed up in a direction substantially parallel to the drawing direction of the existing structure. Then, the lifting force becomes the pulling force of the existing structure, and the lifting force can be further reduced.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 and FIG. 2 are views showing one embodiment of a method of drawing an existing underground structure according to the present invention. In this drawing method, as shown in FIG. 1A, the casing 2 provided with a drilling tip 1 on the lower end circumference of a large diameter pipe surrounds the peripheral surface of the existing structure 3 so as to cover the ground surface. After that, the casing 2 is rotationally propelled with respect to the ground 5 by operating the drive mechanism 4 so as to drill holes over the entire length thereof, and cut off the edges of the existing structure 3 and the ground 5. In this embodiment, by providing the inner surface chip (not shown) on the inner circumferential surface of the casing 2 on an assumed circumferential line having a set diameter smaller than the inner diameter of the casing 2, the inner circumferential surface of the casing 2 and the existing structure 3 are connected. A gap 6 having a set dimension is formed therebetween.
[0011]
Then, as shown in FIG. 4B, when the drilling tip 1 reaches the lowermost end of the casing 2, that is, the depth of the drilling tip 1 is equal to or greater than the lowermost end of the existing structure 3, the rotational propulsion of the casing 2 is stopped. Then, a hole 7 is formed in the existing structure 3 so as to pass from the uppermost end to the lowermost end of the existing structure 3 so as to pass through the central axis of the existing structure 3. Here, the drilled holes 7 are formed along the central axis. However, the drilled holes 7 may be formed so as to be shifted from the central axis, and the drilled holes 7 are connected from the side surface of the existing structure 3 to the lowermost end. The hole 7 may be formed. This is exactly the same in the following embodiments. Reference numeral 8 in the figure denotes a wire, which is attached to the upper part of the existing structure 3 and can lift the existing structure 3 by a heavy machine such as a crane.
[0012]
Next, as shown in FIG. 2A, the jet pump 9 and the temporary recovery tank 10 are connected to the borehole 7 and the casing 2, respectively, by piping. That is, one end of the water supply pipe is connected to the uppermost end of the drilled hole 7 formed as described above, and the other end of the water supply pipe is connected to the discharge port of the jet pump 9. In addition, one end of the drainage pipe is connected to the hollow space of the casing 2 at the upper end side of the casing 2, and the other end of the drainage pipe is connected to the temporary recovery tank 10.
[0013]
When each pipe connection is completed, the jet pump 9 is operated to supply high-pressure water from the jet pump 9 toward the drilled holes 7. Then, the high-pressure water is pumped toward the lowermost end of the existing structure 3 through the drilled hole 7, and the water discharged from the lowermost end is the earth and sand 5a on the ground contacting the lowermost end (FIG. 1 (b)). ) To the gap 6 side. When the water is continuously supplied, the water is also supplied to the gap 6 and the water accumulates inside the casing 2, and the overflowing water is recovered in the temporary recovery tank 10 via a drain pipe. The water containing the collected earth and sand can be discharged as it is, or can be discharged after separating the earth and sand. Of course, water may be used cyclically as needed.
[0014]
By supplying water into the casing 2 in this manner, the existing structure 3 is suspended in the casing 2 in a flooded state, and buoyancy acts on the existing structure 3. Then, as shown in FIG. 2 (b), the existing structure 3 is lifted upward (withdrawal direction) by the wire 8 by the operator operating a heavy equipment such as a crane while receiving the buoyancy, and the ground 5 Pull out from. At this time, it is desirable that water be continuously supplied from the jet pump 9, but the water supply may be stopped during withdrawal.
[0015]
When the drawing is completed, the jet pump 9 is completely stopped, and the trace holes from which the existing structure 3 has been drawn are backfilled with poorly mixed mortar, soil, sand, etc., and then the casing is ground with a crane or wire. To complete the construction.
[0016]
As described above, in this embodiment, after the drilling hole 7 connected to the lowermost end of the existing structure 3 is formed in the existing structure 3, water is directed toward the lowermost end of the existing structure 3 through the drilling 7. To fill the casing 2 with water. As a result, the existing structure is completely separated from the ground 5 and is present in the casing 2 in a flooded state. Therefore, buoyancy acts on the existing structure 3, and when the existing structure 3 is lifted and the existing structure 3 is pulled out from the ground, the lifting force required for pulling out the existing structure 3 is increased by the buoyancy. It can be reduced. As a result, existing structures can be pulled out using heavy machinery with lower lifting capacity than heavy machinery used in the conventional method, improving construction efficiency and reducing construction costs. Can be.
[0017]
In addition, since the existing structure 3 is pulled out not only at the side surface but also at the lowermost end surface in a state where the edge is cut off from the ground 5, efficient pulling-out work can be performed.
[0018]
In addition, the water discharged from the lowermost end of the existing structure 3 is guided into the casing 2 and flows to the ground surface side along the gap 6, so that the water discharged from the lowermost end of the existing structure is efficiently in the casing. And the buoyancy can be reliably given to the existing structure 3.
[0019]
The present invention is not limited to the above-described embodiment, and various changes other than those described above can be made without departing from the gist of the present invention. For example, in the above embodiment, the existing structure 3 is pulled out using the buoyancy and the lifting force. However, as shown in FIG. 3, the lifting force is further increased by adding a lifting force by an actuator such as a hydraulic cylinder. Can be reduced.
[0020]
FIG. 3 is a view showing another embodiment of the method of drawing an underground existing structure according to the present invention. In this drawing method, the lower end of the steel pipe 11 is connected to the upper end of the existing structure 3. For example, when the existing structure 3 is made of concrete, since the pile reinforcement is provided in the existing structure 3, the pile reinforcement and the steel pipe 11 are connected by welding. When the existing structure 3 is a steel pile, the pile main body is directly welded to the steel pipe 11 and connected. Then, the steel beam member 12 is connected to the upper end portion of the steel pipe 11 in a direction substantially perpendicular to the drawing direction (vertical direction in the drawing) by a connection method such as welding. Thus, the auxiliary member including the steel pipe 11 and the steel beam member 12 is attached to the existing structure 3 at a position above the ground surface.
[0021]
A plurality of actuators 13 such as hydraulic jacks are arranged between the upper end portion of the casing 2 and the beam member 12, and when these actuators 13 are actuated, the actuator 13 is substantially in the withdrawal direction (upward direction) of the existing structure. The auxiliary members (the steel pipe 11 and the steel beam member 12) are pushed up in parallel directions, and as a result, it is possible to apply a pushing-up force to the existing structure 3 in the pull-out direction. Therefore, when the existing structure 3 is lifted by the wire 8 by operating a heavy machinery such as a crane and pulled out from the ground 5, at the same time, the rod 13a of the actuator 13 is extended, so that the existing structure 3 is lifted by the pushing force. It is possible to reduce the lifting force required for pulling out. Therefore, it is possible to pull out the existing structure using a heavy machinery having a much lower lifting capacity, thereby improving construction efficiency and suppressing construction cost. The number of actuators 13 such as hydraulic cylinders and the arrangement position are not particularly limited.
[0022]
Further, in the above embodiment, after the casing 2 is rotationally propelled to a predetermined depth, water is supplied from the lowermost end of the existing structure 3 by supplying water through the drilled holes 7 as it is, As shown in FIG. 4, the plurality of steel pieces 21 may be positioned below the lowermost end of the existing structure 3, whereby the following operation and effect can be obtained.
[0023]
FIG. 4 is a diagram showing another embodiment of the method of drawing an underground existing structure according to the present invention. In this embodiment, as shown in the figure, two steel pieces 21 are pivotally supported around a rotation shaft 22 in a gap 6 between the inner peripheral surface of the casing 2 and the existing structure 3. . Each of the billets 21 has a substantially scoop shape, and when the rod 23 of the hydraulic cylinder is extended in a state where the rod 23 is disposed near the lower end of the casing 2, the billets 21 rotate in opposite directions around the rotation shaft 22. It is located below the lowermost end of the existing structure 3 and covers the lowermost end surface of the existing structure 3 (FIG. 2B). In this state, when the jet pump 9 is operated to supply high-pressure water from the jet pump 9 toward the drilling holes 7, high-pressure water is discharged from the lowermost end of the existing structure 3. Is led to the gap 6 side by the steel piece 21. For this reason, water supply can be effectively prevented from seeping into the ground 5, and efficient use of water can be achieved.
[0024]
Further, in the above embodiment, high-pressure water is supplied from the jet pump 9, that is, the water pressure at the time of water supply is increased in order to increase construction efficiency. However, as shown in FIGS. When it is discharged toward the earth and sand 5a (FIG. 1 (b)), not only does the earth and sand 5a flow away, but also the ground 5 is dug deeper. It is possible to prevent the ground 5 from being dug down by the water that has been removed. Therefore, it is advantageous in terms of work efficiency.
[0025]
Further, in the above embodiment, the existing structure 3 is pulled out from the ground 5 at a time, but it is difficult to pull out the existing structure 3 from the ground 5 at a time depending on the size of the existing structure 3 in the pulling-out direction (vertical direction in each drawing). It may be. In this case, after being pulled out to an appropriate position as shown in FIG. 5, the existing structure 3 is cut along, for example, a virtual cutting line (a dashed line in FIG. 5A), and What is necessary is just to repeat the pulling-out operation similar to. At this time, the upper part of the cut existing structure 3 is suspended by a heavy machine such as a crane, but the lower part is released from the suspension and falls into the casing 2 with the cutting. In order to cope with such a problem, in the embodiment shown in FIG. 5, a fall prevention mechanism for preventing the existing structure 3 from falling into the casing 2 even if it is not hung by a heavy machine such as a crane. Is provided.
[0026]
FIG. 5 is a view showing still another embodiment of the underground existing structure drawing method according to the present invention. In this embodiment, four fall prevention mechanisms 30 are provided on the inner wall surface 2a of the casing 2 at equal angular intervals in plan view as shown in FIG. The number of the drop prevention mechanisms 30 is not limited to this, and by providing three or more, the existing structure 3 can be reliably prevented from falling as described later.
[0027]
As shown in FIG. 1C, each of the fall prevention mechanisms 30 includes a main body 31 attached to the inner peripheral surface of the casing 2 and a pivotally supported pivotal movement about the rotation axis 32 with respect to the main body 31. And a stopper 34 for preventing the movable portion 33 from moving more than a predetermined angle. That is, in each of the fall prevention mechanisms 30, the rear end of the movable portion 33 is rotatable about the rotation axis 32 with respect to the inner wall surface 2a of the casing 2 in the range of 0 ° to about 60 °, Is in contact with the side surface 3a of the existing structure 3. Therefore, when the casing 2 moves downward relative to the existing structure 3, the movable part 33 is freely rotatable, and the relative movement is free. Conversely, when the existing structure 3 moves downward relative to the casing 2, the above-described relative movement is possible while the movable portion 33 rotates up to about 60 °. The rear end of the movable portion 33 is locked by the stopper 34, and the movable portion 33 prevents the existing structure 3 from moving downward with respect to the casing 2. In this way, the existing structure 3 can be effectively prevented from dropping, and the existing structure 3 can be pulled out a plurality of times. Therefore, according to this embodiment, it is possible to reliably pull out the existing structure 3 without being limited by the size of the existing structure 3 in the pull-out direction.
[0028]
Further, in the above-described embodiment, the drilled holes 7 are formed after the rotary propulsion of the casing 2. However, the rotary propulsion of the casing is performed after the drilling is formed. It goes without saying that this may be done.
[0029]
Furthermore, in the above embodiment, after the casing 2 is rotationally propelled to a predetermined depth, water is supplied through the drilled holes 7 to discharge water from the lowermost end of the existing structure 3, as shown in FIG. 6. Instead of using the casing 2, water may be discharged from the lowermost end of the existing structure 3 through the hole 7.
[0030]
FIG. 6 is a view showing still another embodiment of the underground existing structure drawing method according to the present invention. In this embodiment, as shown in FIG. 1A, a hole 7 is formed in the existing structure 3 so as to pass through the center axis of the existing structure 3 and connect from the uppermost end to the lowermost end of the existing structure 3. . Then, after connecting the jet pump 9 to the borehole 7 by piping, the jet pump 9 is operated to supply high-pressure water from the jet pump 9 toward the borehole 7. Then, this high-pressure water is pumped toward the lowermost end of the existing structure 3 through the drill hole 7, and a part of the water discharged from this lowermost end is, as shown by an arrow in FIG. The water flows on the ground surface along the outer peripheral side surface of the object 3, and buoyancy acts on the existing structure 3 by the water.
[0031]
Next, as shown in FIG. 2B, an operator operates a heavy equipment such as a crane while receiving the buoyancy to lift the existing structure 3 upward (withdrawing direction) with the wire 8 and to lift the ground. Pull out from 5. At this time, it is desirable that water be continuously supplied from the jet pump 9, but the water supply may be stopped during drawing.
[0032]
Then, when the drawing is completed, the jet pump 9 is completely stopped, and then the trace holes from which the existing structure 3 is drawn are backfilled with poorly-mixed mortar, soil, sand, or the like.
[0033]
As described above, also in this embodiment, since the existing structure 3 is lifted while the buoyancy is applied to the existing structure 3, the existing structure 3 is pulled out from the ground 5, The lifting force required to pull out the existing structure 3 can be reduced by the buoyancy. As a result, existing structures can be pulled out using heavy machinery with lower lifting capacity than heavy machinery used in the conventional method, improving construction efficiency and reducing construction costs. it can. In addition, since the casing 2 is not used, the work process can be simplified, which is more advantageous in terms of construction efficiency and construction cost.
[0034]
【The invention's effect】
As described above, according to the present invention, after forming a drilled hole connected to the lowermost end of the existing structure in the existing structure, water is supplied to the lowermost end of the existing structure through the drilled hole. As the buoyancy acts on the existing structure, it is possible to pull out the existing structure with a smaller lifting force than the conventional method.In other words, it is possible to pull out the existing structure using a heavy machinery machine with a higher lifting capacity. This makes it possible to improve construction efficiency and reduce construction costs.
[Brief description of the drawings]
FIG. 1 is a view showing an embodiment of a method for drawing an underground existing structure according to the present invention.
FIG. 2 is a view showing an embodiment of a method for drawing an underground existing structure according to the present invention.
FIG. 3 is a view showing another embodiment of a method for drawing an underground existing structure according to the present invention.
FIG. 4 is a view showing another embodiment of a method for drawing an underground existing structure according to the present invention.
FIG. 5 is a view showing still another embodiment of the drawing method of the existing underground structure according to the present invention.
FIG. 6 is a view showing still another embodiment of the method for extracting an underground existing structure according to the present invention.
[Explanation of symbols]
2 ... casing 3 ... existing structure 5 ... ground 7 ... drilled holes 11 ... steel pipe (auxiliary member)
12 ... Steel beam member (auxiliary member)
21 ... Slab

Claims (4)

In a drawing method for pulling out an existing structure buried underground, a first step of forming a hole in the existing structure that is connected to the lowermost end of the existing structure,
A second step of supplying water toward the lowermost end of the existing structure through the hole to give buoyancy to the existing structure;
And a third step of lifting the existing structure while applying buoyancy to the existing structure. Before the second step, a fourth step is further provided in which a casing is rotatably propelled to the ground so as to surround the existing structure so that a front end portion of the casing reaches a depth equal to or more than a lowermost end of the existing structure. The method for drawing out an existing underground structure according to claim 1. The method of drawing out an existing underground structure according to claim 2, further comprising a fifth step of positioning a plurality of steel slabs below a lowermost end of the existing structure before the second step. A sixth step of attaching an auxiliary member to the existing structure at a position above the ground surface before the third step;
4. The underground existing structure withdrawal according to claim 1, further comprising a seventh step of pushing up the auxiliary member in a direction substantially parallel to the withdrawal direction of the existing structure together with the third step. Construction method.

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