JP2007211533A - Method for removing underground structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for rapidly and easily removing an underground structure. <P>SOLUTION: A plurality of chain conveyor cutters are arranged facing on both sides of the underground structure. Bits 13, facing a pile 1, out of a plurality of bits 13 provided at each of the plurality of chain conveyor cutters are set in a direction to face the ground, and the plurality of bits 13 are brought into contact with the side face of the pile 1 to rake up the side face of the pile 1 by the plurality of bits 13. Time, labor and cost required for the removal of the underground structure can be considerably reduced in comparison with a conventional removal method by force. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for removing underground structures embedded in the ground such as existing piles (such as ready-made piles and cast-in-place piles) and continuous walls.

  In recent years, mainly in the vicinity of large cities, there are increasing cases of demolishing old factories and aging buildings (for example, commercial buildings and residential apartments) and reusing land. This is thought to be due to the fact that almost 50 years have passed since the start of construction of concrete buildings in Japan. Such cases will continue to increase in the future.

  Buildings require a suitable foundation, and there are cases where continuous walls are built in the ground as a countermeasure against soil contamination. In order to renew a building, it is necessary to remove underground structures related to the objects after removing the objects.

  In particular, a large-diameter cast-in-place pile can be cited as an underground structure that is difficult to remove. For example, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2003-34932), it is common to use a casing to remove the cast-in-place pile.

  Next, an outline of the prior art will be described with reference to FIGS. As shown in FIG. 15, the pile 1, which is an underground structure to be removed, is often cylindrical with a diameter of about 60 cm to 200 cm, and there is a large one whose axial length reaches 50 m. . And the bottom part becomes the rib 1a formed wide. The pile 1 is made of concrete as a main material, and as shown in FIG. The reinforcing bar 3 includes a plurality of thick main bars 3a and a cylindrical horizontal bar 3b connecting the main bars 3a. As shown in FIG. 16, a part of the reinforcing bar 3 may become a burr 3c and may be exposed from the pile 1 to the outside. Moreover, as shown in FIG. 15, it is desirable that the pile 1 is formed straight and smoothly in the vertical direction. However, in practice, the pile 1 is eccentric, uneven, burred, or bent. There are often some problems.

  The casing 2 is an apparatus for constructing the pile 1 originally. When the pile 1 is removed, a casing 2 that is slightly larger than the pile 1 to be removed is used, and the outer periphery of the pile 1 is further separated from the outer periphery by the teeth 2a formed at the lower end of the casing 2 (usually “ The wire 4 hung on the pile 1 is pulled by a large crane, and the pile 1 is pulled out. At the same time, water is supplied to the vicinity of the casing 2 and the edge-cut soil is made to be mud to facilitate extraction.

  However, the axial direction of the casing 2 and the pile 1 is not necessarily parallel, and the casing 2 often does not advance as expected. In addition, if there is a problem with the pile 1 itself as described above, the drawing work is difficult to perform immediately. In addition, the load for pulling out the pile 1 is only the traction force by the wire 4, and even if a constant traction force is applied to the wire 4 by a large crane, the resistance of the pile 1 fluctuates. Repeatedly, no matter how thick and tough the wire 4 is used, the wire 4 often breaks. When this happens, it is inevitable that the construction will be difficult, for example, it is necessary to remove the existing wire 4 and hang a new wire again.

  In fact, it takes a few months to pull out a single stake, and it often happens that no matter how much time it takes to pull it out. For this reason, the construction cost for pulling out one stake may vary from several million yen to 10 million yen in some cases.

The present inventors propose a new technique by paying attention to the fact that there is a limit to the above-mentioned method of giving power. There are similar problems with the removal of other underground structures.
JP 2003-34932 A

  Then, an object of this invention is to provide the method of removing an underground structure quickly and easily.

  The removal method according to the first aspect of the present invention is to set a plurality of bits provided on the chain conveyor cutter that face the underground structure in a direction facing the ground, and set the plurality of bits to the side surface of the underground structure. The side surface of the underground structure is scraped up by a plurality of bits.

  The removal method according to the second aspect of the present invention is to arrange a plurality of chain conveyor cutters so as to face each other with an underground structure sandwiched therebetween, and a plurality of bits provided in each of the plurality of chain conveyor cutters. The object facing the structure is set in a direction facing the ground, a plurality of bits are brought into contact with the side surface of the underground structure, and the side surface of the underground structure is scraped up by the plurality of bits.

  In these configurations, the plurality of bits scoop up the side surface of the underground structure toward the ground, so that the underground structure is not only cut off from the surrounding soil but also subjected to a load in the direction of lifting by the bits. Therefore, the underground structure can be pulled out much more easily than in the case of using only the traction force by the wire. Even if there are some bends, irregularities, burrs, etc. in the underground structure, it is possible to remove them with a bit, or they can be used as a trigger to bite them up .

  It is more preferable that the plurality of chain conveyor cutters are arranged so as to face each other with the underground structure sandwiched therebetween, because the underground structure can be lifted from both sides.

  In the removal method according to the third invention, in addition to the first invention, the chain conveyor cutter discharges the discharge liquid to the lower part of the underground structure.

  With this configuration, the pressure of the discharge liquid can be used to lift the underground structure, and the drawing can be easily performed, and the space formed as a result of the extraction of the underground structure can be filled with the discharge liquid. The change in the ground due to a sudden change in earth pressure can be suppressed.

  In the removing method according to the fourth invention, in addition to the first invention, the discharge liquid contains water.

  With this configuration, the edge-cut soil is made muddy and can be pulled out more easily.

  In the removal method according to the fifth invention, in addition to the first invention, the discharge liquid contains a solidifying material.

  With this configuration, if the solidified material is solidified, the ground strength can be made inferior to the state before drawing.

  In the removal method according to the sixth invention, in addition to the first invention, a gap is formed between the plurality of H steels by cutting with a chain conveyor cutter between the plurality of H steels, and a crack is generated in the dangerous section. Let

  With this configuration, when there are a plurality of H steels in the underground structure, the underground structure can be divided into a plurality of parts due to the occurrence of cracks, and the large underground structure can be subdivided and easily removed. .

  In the removal method according to the tenth invention, in addition to the first invention, a crack is generated by utilizing a difference in earth pressure to the continuous wall.

  With this configuration, a large underground structure can be subdivided without applying a special external force.

  In the removing method according to the eleventh invention, in addition to the first invention, a hole that faces the axial direction is made in the underground structure by a chain conveyor cutter.

  With this configuration, a part of the underground structure can be removed before the underground structure is extracted, and the weight of the underground structure to be extracted can be reduced.

  In the removing method according to the twelfth invention, in addition to the first invention, the underground structure is divided into a plurality of portions in the axial direction by the chain conveyor cutter.

  With this configuration, a large underground structure can be subdivided and easily removed.

  According to the present invention, the plurality of bits scrape the side surface of the underground structure toward the ground, so that the underground structure is not only cut off from the surrounding soil, but also receives a load in the direction of lifting by the bit. . Therefore, the underground structure can be pulled out much more easily than in the case of using only the traction force by the wire. As a result, the time, labor, and cost required to remove the underground structure can be greatly reduced.

  Next, embodiments of the present invention will be described with reference to the drawings. Fig.1 (a) is a front view of the chain conveyor cutter used for the removal method of an underground structure in embodiment of this invention, FIG.1 (b) is the same side view.

  Hereinafter, based on FIG. 1, the structure of this chain conveyor cutter 10 is demonstrated. Now, as shown in FIG. 1, this chain conveyor cutter 10 is a chain saw type chain conveyor cutter. That is, an endless chain 12 is stretched around a vertically long post 11 having a square cross section, and a number of bits 13 project outward from the outer periphery of the endless chain 12. The bit 13 (particularly, the bits at the four corners) is desirably a super hard cutter bit when cutting a reinforcing bar.

  The endless chain 12 circulates in the direction of the arrow M <b> 1 when a driving force is applied from the driving device 14 to the endless chain 12.

  Here, the drive device 14 includes a prime mover 15 such as a motor, and a speed reducer 16 that decelerates the driving force of the prime mover 15 at a predetermined gear ratio and transmits it to the endless chain 12.

  Further, as shown in an enlarged view in FIG. 2, a return roller 17 is rotatably supported at the lower end of the post 11, and the plurality of bits 13 are in circumferential contact with the return roller 17, Turn back from the descending direction to the ascending direction.

  When the chain conveyor cutter 10 excavates the underground vertically downward, the bit 13 performs excavation work only near the return roller 17, that is, near the lower end of the post 11. On the other hand, as will be described later, when the underground structure is scraped up, the side bit 13 rising in the direction of the arrow M1 plays a main role.

  Further, as shown in FIG. 3, the hook 20 of the crawler crane 19 is engaged with the connecting portion 18 at the upper end of the chain conveyor cutter 10, and the chain conveyor cutter 10 is moved by the crawler crane 19. Can be pulled up from the ground.

  Conversely, the chain conveyor cutter 10 excavates the ground by its own weight and the work of the bit 13. Of course, when the chain conveyor cutter 10 excavates in the ground, the position of the hook 20 of the crawler crane 19 may be lowered in accordance with the chain conveyor cutter 10. However, at this time, the crawler crane 19 does not apply a load to be pushed down to the chain conveyor cutter 10.

  In addition, as long as the chain conveyor cutter 10 can be pulled out from the ground or moved in the horizontal direction, an arbitrary device may be used instead of the crawler crane 19 illustrated.

(Overview)
Next, taking the pile 1 as an example of the underground structure, an outline of the method for removing the underground structure of the present invention will be described.

  First, as shown in FIG. 4, a wire 4 hanging from a crawler crane (separate from the chain conveyor cutter) is hung on the pile 1. Next, these chain conveyor cutters are set so that the respective bits 13 of the pair of chain conveyor cutters are directed upward on the peripheral surface side of the pile 1, and excavation in the ground is started. And a chain conveyor cutter is advanced to the lower end part of the pile 1, and the rib 1a is cut and removed by these bits 13. FIG. At this time, the discharge liquid is discharged from the pump 31 from the discharge port 32 provided in the lower part of the chain conveyor cutter, and the edge-cut soil is made muddy.

  Next, when the chain conveyor cutter reaches the lower end of the pile 1, as shown in FIG. 5, the chain conveyor cutter is rotated at low speed and high torque, and the peripheral surface of the pile 1 is scraped up by the bit 13. At the same time, the discharge liquid 30 (preferably one in which soil cement is poorly mixed) is discharged from the discharge port 32, and the inflow pressure of the discharge liquid 30 is applied in the direction of lifting the pile 1. At this time, the pile 1 is in a state of being immersed in a viscoelastic fluid formed by the mud and the discharge liquid 30 and is separated from the surrounding soil and receives pressure and buoyancy from the fluid.

  As a result, the pile 1 rises and a space is formed in the lower portion of the pile 1, but since this space is filled with the discharge liquid 30, loosening of the ground is suppressed. Then, as shown in FIG. 6, the pile 1 reaching the ground is lifted by the wire 4 and removed.

The use of a chain conveyor cutter for removing underground structures has the following advantages.
(1) Since the chain conveyor cutter can be set at an arbitrary position, it is easy to control the cutting position and can be carried out in a narrow place. Since the soil can be cut to a deep position, it is suitable for removing underground structures located deep in the ground.
(2) It can cut not only unconsolidated ground, but also reky soil, bedrock and concrete itself.
(3) Since vertical holes are formed, earth retaining work is not required even in permeable ground where the groundwater level is shallow.
(4) In soft ground, fluidization of soil can be promoted by high cutting stirring ability.
(5) On loose ground, solidification can be used to improve the ground.
(6) A super hard cutter bit can be used, and not only concrete but also reinforcing steel bars and some steel materials can be broken.

  Hereinafter, various embodiments according to the types of underground structures will be described.

(Embodiment 1)
The underground structure is a pile having a relatively small diameter (diameter: 120 cm or less). For soil, sand, silt, etc., which have low adhesiveness are targeted.

  While excavating and stirring the peripheral soil of the pile with a chain conveyor cutter (with water injection), the peripheral soil is softened or fluidized, and the resistance force by the peripheral surface of the pile is greatly reduced and pulled out.

  As shown in FIG. 7, the peripheral soil of the pile is cut and stirred by a chain conveyor cutter, and 2 to 4 vertical holes (the number is increased or decreased in consideration of the resistance force of the peripheral surface).

  At this time, water is discharged from the discharge port 32 of the chain conveyor cutter toward the pile. Then, since water has a property of selecting a path with less resistance and flowing, as a result, as shown by an arrow in FIG. 7, water passes through the path from the first vertical hole to the second vertical hole and the reverse path. A passageway is formed, and the surrounding soil is softened or fluidized.

  When pulling out, the scraping force by the bit 13 is used as shown in FIG.

(Embodiment 2)
The underground structure is a pile having a relatively small diameter (diameter: 120 cm or less). The soil is targeted for highly sticky soils such as Kanto Loam.

  While excavating and stirring the peripheral soil of the pile with a chain conveyor cutter (with water injection), the peripheral soil is softened or fluidized, and the resistance force by the peripheral surface of the pile is greatly reduced and pulled out.

  As shown in FIG. 8, the peripheral soil of the pile is cut and stirred by a chain conveyor cutter, and a plurality of vertical holes (the number is increased or decreased in consideration of the resistance force of the peripheral surface) is formed, and the pile is surrounded by the vertical holes. At this time, water is discharged from the discharge port 32 of the chain conveyor cutter toward the pile.

  When pulling out, the scraping force by the bit 13 is used as shown in FIG.

(Embodiment 3)
The underground structure is a pile having a relatively large diameter (diameter: 120 cm or more). Soil stickiness can be strong or weak.

  First, as shown in FIG. 9, the inside of the pile 41 is cut with a chain conveyor cutter to form a first vertical hole. At this time, it is desirable to cut the reinforcing bar 41a with the bit 13 of the chain conveyor cutter.

  Further, the peripheral soil is cut and agitated by the chain conveyor cutter, and the periphery of the pile 41 is cut. Thereby, the second vertical hole to the tenth vertical hole are formed, and the remaining part of the pile 41 is separated into the outer edge parts 42 to 45 and subdivided.

  Then, the separated outer edge portions 42 to 45 are pulled out to the ground by the scraping force by the bit of the chain conveyor cutter and the pulling force by the crane. In addition, it is desirable to recycle the fragments of the pile 41.

(Embodiment 4)
The underground structure is a pile having a relatively large diameter (diameter: 120 cm or more). Soil stickiness can be strong or weak.

  First, as shown in FIG. 10, the inside of the pile 41 is cut with a chain conveyor cutter to form a first vertical hole. At this time, it is desirable to cut the reinforcing bar 41a with the bit 13 of the chain conveyor cutter.

  Next, the second vertical hole is formed by changing the angle with the first vertical hole. At this time, it is desirable to cut the reinforcing bar 41a with the bit 13 of the chain conveyor cutter.

  Further, while changing the angle of the chain conveyor cutter, the peripheral soil is cut and agitated, and the periphery of the pile 41 is cut. Thereby, the third vertical hole to the eighth vertical hole are formed, and the remaining portion of the pile 41 is separated into the outer edge portions 46 to 51 and subdivided.

  Then, the separated outer edge portions 46 to 51 are pulled out to the ground by the scraping force by the bit of the chain conveyor cutter and the pulling force by the crane. In addition, it is desirable to recycle the fragments of the pile 41.

(Embodiment 5)
Underground structures are all piles, underground beams, and underground walls. The whole underground structure is cut and crushed by the chain conveyor cutter. Recycle the debris.

(Embodiment 6)
The underground structure is a continuous wall. As shown in FIG. 11, this continuous wall is formed by constructing a plurality of cylindrical bodies 53 containing H steel 53 coaxially so as to overlap each other. The cross section of the cylindrical body 53 is a circle in the drawing, but other shapes such as a rectangle may be used. 11, 12, and 14, it is assumed that the upper side of the cylindrical body 53 is the outer side of the continuous wall and the lower side is the inner side.

  Now, as shown in FIG. 12, the chain conveyor cutter is set obliquely with respect to the continuous wall so that the tip of the bit reaches the gap between the H steels 53. And the cutting by a chain conveyor cutter is implemented and the 1st-4th vertical hole is formed. At this time, the interval between the tip portions of the bits is usually about 5 cm, but may be narrower if possible. As a result, a dangerous cross section is intentionally formed in the continuous wall, cracks 54 and 55 are generated in the critical cross section due to shear fracture, and the long continuous wall is subdivided with the cracks 54 and 55 as a boundary. Of course, the number of cracks can be variously changed as required. For example, the number of thin continuous walls is reduced, and the thickness of thick continuous walls is increased.

  That is, as shown in FIG. 13, when the dangerous cross section is formed, the inside of the continuous wall is cut and stirred by the chain conveyor cutter in the vicinity thereof to form the fifth to eighth vertical holes as shown in FIG. .

  At this time, as can be seen by carefully looking at FIG. 13, in the state in which the fifth to eighth vertical holes are formed to some extent, the soil does not already exist inside the continuous wall or the soil fluidizes and the earth pressure decreases. ing. On the other hand, the soil exists outside the continuous wall as before. That is, the earth pressure acting on the continuous wall from the outside becomes larger than the earth pressure acting on the continuous wall from the inside, and a difference in earth pressure is generated. When this earth pressure difference exceeds a certain level, the dangerous cross section can no longer withstand the earth pressure difference, and shear breaks and cracks 54 and 55 are generated.

  At this time, if the chain conveyor cutter is slowly advanced and the vicinity of the dangerous section is visually observed, it should be perceivable whether a crack has occurred. Therefore, the operation of the chain conveyor cutter does not have to be controlled using a complicated measurement system.

  Thereafter, the fifth to eighth vertical holes are formed to a predetermined depth, and the outer ninth to twelfth vertical holes are formed opposite to these, and the partial walls 60 to 62 divided by the cracks 54 and 55 are formed. Are sequentially pulled out to the ground.

  In addition, after the formation of a crack, if the outer mass of the outer wall of the continuous wall is greatly displaced and there is a concern about the influence on the adjacent structure, measures such as refilling the soil dug out by forming the inner vertical hole It is desirable to control the earth pressure displacement.

(A) Front view of chain conveyor cutter used in the method for removing underground structures in the embodiment of the present invention (b) Side view The lower end enlarged view of FIG. Elevated view of chain conveyor cutter in an embodiment of the present invention Process explanatory drawing of the removal method of the underground structure Process explanatory drawing of the removal method of the underground structure Process explanatory drawing of the removal method of the underground structure Process explanatory drawing of the underground structure removal method in Embodiment 1 of this invention Process explanatory drawing of the removal method of underground structure in Embodiment 2 of the present invention Process explanatory drawing of the removal method of underground structure in Embodiment 3 of this invention Process explanatory drawing of the removal method of underground structure in Embodiment 4 of this invention Process explanatory drawing of the removal method of underground structure in Embodiment 6 of this invention Process explanatory drawing of the removal method of underground structure in Embodiment 6 of this invention Process explanatory drawing of the removal method of underground structure in Embodiment 6 of this invention Process explanatory drawing of the removal method of underground structure in Embodiment 6 of this invention Process explanatory drawing of the conventional removal method of underground structure Process explanatory drawing of the conventional removal method of underground structure

Explanation of symbols

1, 40, 41 Pile 1a Rib 2 Casing 2a Teeth 3, 41a Reinforcing bar 3a Main bar 3b Horizontal bar 3c Burr 4 Wire 10 Chain conveyor cutter 11 Post 12 Endless chain 13 Bit 14 Drive device 15 Motor 16 Reduction gear 17 Return roller 18 Connecting part 19 Crawler crane 20 Hook 30 Discharge liquid 31 Pump 32 Discharge port 42-51 Outer edge part 52 Cylindrical body 53 H steel 54, 55 Crack 60-62 Partial wall G Ground

Claims (12)

Set a plurality of bits provided on the chain conveyor cutter facing the underground structure in the direction facing the ground,
A method for removing an underground structure, wherein the plurality of bits are brought into contact with a side surface of the underground structure, and the side surface of the underground structure is scraped up by the plurality of bits. A plurality of chain conveyor cutters are arranged so as to face each other with an underground structure sandwiched therebetween, and a plurality of bits provided in each of the plurality of chain conveyor cutters that face the underground structure are disposed on the ground. Set in the direction facing
A method of removing an underground structure, wherein the plurality of bits are brought into contact with a side surface of the underground structure, and the side surface of the underground structure is scraped up by the plurality of bits. The underground conveyor structure removing method according to claim 1 or 2, wherein the chain conveyor cutter discharges a discharge liquid to a lower portion of the underground structure. The method for removing an underground structure according to claim 3, wherein the discharge liquid includes water. The method for removing an underground structure according to claim 3, wherein the discharge liquid includes a solidifying material. The method for removing an underground structure according to any one of claims 1 to 5, wherein the underground structure is an existing pile. The method for removing an underground structure according to claim 1, wherein the underground structure is a continuous wall. The said continuous wall is a removal method of the underground structure of Claim 7 containing several H steel. The removal of underground structures according to claim 8, wherein a gap is formed between the plurality of H steels by cutting between the plurality of H steels by the chain conveyor cutter, and cracks are generated in the danger cross sections. Method. The method for removing an underground structure according to claim 9, wherein the crack is generated using a difference in earth pressure to the continuous wall. The method for removing an underground structure according to any one of claims 1 to 10, wherein a hole is formed in the underground structure in the axial direction by the chain conveyor cutter. The method for removing an underground structure according to any one of claims 1 to 11, wherein the underground structure is divided into a plurality of portions in the axial direction by the chain conveyor cutter.

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