JP3872094B2 - Liner plate shaft formation method - Google Patents

Description

  The present invention includes, for example, an upper support for a liner plate shaft used for a shaft for a foundation for a deep foundation method, a start shaft and a reaching shaft for a sewer propulsion method, a well for preventing landslide, a liner The present invention relates to a method for forming a liner plate shaft using an intermediate support of the plate shaft.

  FIG. 9 is a schematic longitudinal sectional view showing an example of a conventional liner plate shaft used for foundation construction of a power transmission tower and its upper support and intermediate support. In the figure, 10 is a shaft, and the shaft 10 is a cylindrical upper shaft 12 drilled vertically from the ground, and a cylindrical lower shaft drilled vertically further from the bottom of the upper shaft 12. It consists of a shaft 14.

  The lower shaft 14 has a diameter smaller than the diameter of the upper shaft 12, and the center thereof is formed at a position slightly shifted laterally (left side in the figure) from directly below the upper shaft 12. A ring-shaped upper support 16 is provided around the upper edge of the upper shaft 12, and a ring-shaped intermediate support 18 is provided around the upper edge of the lower shaft 14 at the bottom of the upper shaft 12. Both the upper support 16 and the intermediate support 18 are made of concrete.

  The inner wall of the upper shaft 12 and the inner wall of the lower shaft 14 are respectively covered with liner plates (steel materials obtained by corrugating a thin steel plate and forming a flange around it) 20 and 22. The liner plate 20 covering the inner wall of the upper shaft 12 is supported by being hung from the side by the upper support 16 with the upper end slightly protruding from the ground. The liner plate 22 covering the inner wall of the lower shaft 14 is supported by being suspended by an intermediate support 18.

  These shafts are formed as follows, for example. That is, a hole slightly larger than the diameter of the upper shaft 12 to be formed is dug by about 1 to 3 rings of the liner plate, and the liner plate 20 is assembled into a cylindrical shape in this hole. After assembling the liner plate 20, the level and roundness of the liner plate 20 are confirmed, and concrete is placed between the liner plate 20 and the natural ground 24. The placed concrete hardens to become the upper support 16, and the upper portion of the liner plate 20 is fixed to the surrounding natural ground.

  After the concrete is hardened and the upper portion of the liner plate 20 is fixed to the surrounding natural ground, the hole is further drilled downward, and the liner plate 20 is added further downward. Here, in order to prevent the natural ground 24 from collapsing, the hole is not excavated so much, but the hole is excavated as much as possible, and the liner plate 20 is added. Further, the liner plates 20 are assembled alternately (staggered) so that the shaft joints do not pass in the vertical direction so that the overall strength is not reduced. The upper shaft 12 is formed by the above operation.

  Next, a hole having a diameter smaller than that of the upper shaft 12 is dug by about 1 to 3 rings of the liner plate so that the center thereof is slightly shifted from the center of the upper shaft 12 in the horizontal direction (left side in the figure). Thus, the liner plate 22 is assembled into a cylindrical shape. After assembling the liner plate 22, the level and roundness of the liner plate 22 are confirmed, and concrete is placed between the liner plate 22 and the natural ground 24. Here, the placed concrete hardens to become the intermediate support 16, and the upper edge of the liner plate 22 is fixed to the surrounding natural ground.

  After the concrete is hardened and the upper edge of the liner plate 22 is fixed to the surrounding ground, the hole is further drilled downward, and the liner plate 22 is added further downward. Also here, in order to prevent the collapse of the natural ground 24, the hole is not excavated too much, but the hole is excavated as much as possible, and the liner plate 22 is added in the same manner as the upper shaft. The lower shaft 14 is formed by the above operation.

  In the above-described example, the shaft is divided into the upper shaft 12 and the lower shaft 14, and the diameter of the lower shaft 14 is slightly smaller than the diameter of the upper shaft 12, but this is a transmission tower in one shaft. If the shaft is formed so that the diagonal legs are buried, the shaft will be wider at the bottom of the shaft than is necessary for the oblique legs of the transmission tower to be buried. This was done in order to reduce the excavation work of the shaft.

  By the way, since the upper support and the intermediate support of the conventional liner plate shaft are formed of concrete as described above, it is possible to proceed with the excavation work and the liner plate addition work until the concrete is hardened and has a predetermined strength. Therefore, there is a problem that it takes time to form the shaft.

  Also, when concrete is placed between the liner plate and the ground to form a shaft support, a formwork is installed to prevent the liner plate from moving or tilting, Since it is necessary to prevent the liner plate from being deformed by inserting a support material inside, there is a problem that the preparation work for placing concrete is troublesome.

  Furthermore, when forming a foundation for a transmission tower in an inconvenient location between mountains, it is often necessary to knead ready-mixed concrete to form a shaft support in another place and transport it by helicopter. There was a problem that transportation was expensive and the cost of forming the shaft was high.

  An object of the present invention is to provide a liner plate shaft upper support, an intermediate support, and a method for forming a liner plate shaft, which can easily and inexpensively form a liner plate shaft in a short period of time.

  The method for forming a liner plate shaft according to the present invention includes a step of connecting a liner plate in a ring shape in a shallow hole at the top of the shaft, and a ring shape while being connected to a liner plate connected in a ring shape on the ground. Assembling the upper support so as to surround the upper edge of the liner plate, and excavating the lower part of the liner plate connected in a ring shape, adding the liner plate to the lower part of the ring liner plate to form a shaft The upper support includes a donut-shaped upper plate, a donut-shaped lower plate provided coaxially and in parallel at a predetermined interval below the upper plate, and a plurality of upper plates and lower plates connected to each other. The upper plate and the lower plate have an inner diameter substantially equal to the outer diameter of the liner plate shaft to be supported.

  Moreover, you may have the process of adding a liner plate to the upper edge part of the ring-shaped liner plate which connected the upper support.

  The intermediate support includes a step of assembling the intermediate support at a position shifted laterally from the center of the bottom of the shaft, and a step of adding a liner plate to the intermediate support while excavating the lower portion of the intermediate support, A donut-shaped upper plate, a donut-shaped lower plate provided coaxially and in parallel below the upper plate at a predetermined interval, and a plurality of connecting members for connecting the upper plate and the lower plate, The lower plate has an outer diameter substantially equal to one liner plate shaft formed above, and an inner diameter approximately equal to an outer diameter of another liner plate shaft formed below one liner plate shaft, A ring-shaped circumferential stiffening plate may be provided coaxially with the inner periphery of the lower plate on the lower plate.

  According to the present invention, it is not necessary to wait for a curing period (usually a curing period of about 4 weeks is required) until the concrete for supporting the shaft has a predetermined strength as in the prior art, so mortar as a backfill material Once the shaft is hardened, the shaft excavation and liner plate addition can proceed immediately after the shaft support is installed, so that the shaft can be formed in a short time. is there.

  Further, according to the present invention, when concrete is placed between a liner plate and a natural ground to form a shaft support as in the prior art, a formwork is installed in earnest to move or tilt the liner plate. It is not necessary to prevent the deformation of the liner plate by installing a support material in earnest, so that the preparation work can be reduced.

  Further, according to the present invention, since the shaft support is formed so as to be assembled, it is not necessary to transport a large amount of ready-mixed concrete with a helicopter as in the prior art, and the material transportation cost can be reduced. There is an effect that the shaft can be formed at low cost.

  Further, according to the present invention, since the shaft support can be assembled only with bolts and nuts, there is an effect that the shaft can be easily formed even at an inconvenient place such as a mountain slope. FIG. 8 shows an example in which a liner plate shaft is formed on an inclined ground as a reference example.

  Further, according to the present invention, since the shaft support can be assembled with bolts and nuts, the shaft support can be disassembled and used repeatedly, and therefore the shaft can be formed at low cost. There is. Further, by increasing the size of the lower plate 34 of the upper support 28 and increasing the contact area with the ground, there is an effect that it can cope with the soil condition (softness) to some extent.

  Furthermore, according to the present invention, when the upper plate portion of the intermediate support for shafts is formed of a striped steel plate, it is difficult for a person or an operator to slide, so there is an effect that safety is high.

  FIG. 1 is a schematic longitudinal sectional view of a liner plate shaft using an upper support and an intermediate support according to an embodiment of the present invention. In the figure, 10 is a shaft, and the shaft 10 is a cylindrical upper shaft 12 drilled vertically from the ground, and a cylindrical lower shaft drilled vertically further from the bottom of the upper shaft 12. It consists of a shaft 14. The lower shaft 14 is smaller in diameter than the upper shaft 12, and the center thereof is formed at a position slightly shifted laterally (left side in the figure) from the center of the upper shaft 12.

  The inner wall of the upper shaft 12 and the inner wall of the lower shaft 14 are respectively covered with liner plates (steel materials obtained by corrugating a thin steel plate and forming a flange around it) 20 and 22. The liner plate 20 covering the inner wall of the upper shaft 12 is supported so as to be suspended from the side by an upper support 28 with its upper end slightly protruding from the ground. The liner plate 22 covering the inner wall of the lower shaft 14 is supported by being suspended by an intermediate support 30.

  2 is a plan view of an upper support according to an embodiment of the present invention, FIG. 3 is a view taken along arrow AA in FIG. 2, and FIG. 4 is a view taken along arrow BB in FIG. As shown in these drawings, the upper support 28 includes a donut-shaped upper plate 32, a donut-shaped lower plate 34 provided coaxially and parallel below the upper plate 32 at a predetermined interval, and an upper plate 32. And a plurality of connecting members 36 for connecting the lower plate 34.

  The upper plate 32 and the lower plate 34 have an inner diameter substantially equal to the outer diameter of the liner plate 20 of the upper shaft 12 to be supported, and the outer diameter of the lower plate 34 is larger than the outer diameter of the upper plate 32. If the lower plate 34 is formed widely, the upper support 28 can be stably seated on the ground. A ring-shaped water shielding plate 38 is coaxially provided on the lower plate 34.

  The connecting member 36 includes a vertical member 40 that connects the upper plate 32 and the lower plate 34 between the upper plate 32 and the lower plate 34, and a base end portion 34 </ b> A at the lower end portion of the vertical member 40 on the lower plate 34. Are connected to each other, and the tip end portion 34B is directed in the radial direction, and the oblique side member 44 is connected to the tip end portion of the base member 42 and the upper end portion of the vertical member 40.

  Each of the upper plate 32 and the lower plate 34 is divided into four parts so as to be connectable, and each part of the divided upper plate 32 and each part of the divided lower plate 34 are connected by a connecting member 36 to form a block. That is, the upper support 28 is divided into four parts, and two types of blocks (A) and (B) are alternately arranged on a concentric circle and can be connected by bolts and nuts.

  Here, the upper plate 32 and the lower plate 34 are made of two types of blocks because, when the block and the liner plate 20 are connected by bolts and nuts, due to the pitch circle of the bolt holes of the liner plate 20, for example, This is because when the block is divided into four, the case where the pitch of the block does not match the pitch of the liner plate 20 is taken into consideration, and one block may be used as long as the pitch of the block completely matches the pitch of the liner plate 20 (FIG. 2). reference).

  5 is a plan view of an intermediate support according to an embodiment of the present invention, FIG. 6 is a view taken along the line CC in FIG. 5, and FIG. 7 is a view taken along the line DD in FIG. As shown in these drawings, the intermediate support 30 includes a donut-shaped upper plate 46, a donut-shaped lower plate 48 provided coaxially and parallel below the upper plate 46 at a predetermined interval, and an upper plate 46. And a plurality of connecting members 36 (described later) for connecting the lower plate 48.

  The upper plate 46 and the lower plate 48 have an outer diameter substantially equal to the liner plate 20 formed in a ring shape above, and an inner diameter substantially equal to the outer diameter of the liner plate 22 formed in a ring shape below. The center of the central hole formed in the upper plate 46 and the lower plate 48 is slightly shifted from the center of the outer periphery.

  The connecting member 36 includes a back plate 52 that connects the outer periphery of the upper plate 46 and the outer periphery of the lower plate 48, an end stiffening plate 54 that connects the end of the upper plate 46 and the end of the lower plate 48, and An intermediate stiffening plate 56 provided radially between the upper plate 46 and the lower plate 48 is used. On the lower plate 48, a ring-shaped circumferential stiffening plate 58 is provided coaxially. The upper plate 46 may be formed of a striped steel plate. In this case, there is an advantage in terms of safety that it is difficult for a person or an operator to slide.

  Each of the upper plate 46 and the lower plate 48 is divided into five so as to be connectable, and each divided upper plate 46 and each divided lower plate 48 are connected to each other by the connecting members described above to form a block. That is, the intermediate support 30 is divided into five parts, and the blocks (A) to (E) are alternately installed on concentric circles and connected by bolts and nuts.

  The upper support 28 and the intermediate support 30 described above are all made of steel.

  The shaft according to the present invention can be formed as follows, for example. That is, a hole slightly larger than the diameter of the upper shaft 12 to be formed is dug by about 1 to 3 rings of the liner plate, and the liner plate 20 is assembled into a cylindrical shape in this hole. At this time, the upper edge portion of the liner plate 20 is positioned at the same height as the hole.

  Next, the horizontality and roundness of the liner plate 20 are confirmed, and a mortar is put between the liner plate 20 and the natural ground 24 and backed up, and the upper portion of the liner plate 20 is fixed to the surrounding natural ground. At this time, the height of the mortar is set to the same height as the liner plate 20.

  Next, the ground around the liner plate 20 is leveled to the same height as the lower plate 34 of the upper support 28 or slightly wider than the upper edge of the liner plate 20, and the liner plate 20 is further laid. In addition to adding one or two rings upward, the blocks of the upper support 28 are arranged on the ground so as to surround the liner plate 20, and these are assembled in a ring shape with bolts and nuts and connected to the liner plate 20.

  Next, the lower hole of the liner plate 20 is drilled further downward, and the liner plate 20 is added further downward. Here, in order to prevent the natural ground 24 from collapsing, the hole is not excavated so much, but the hole is excavated as much as possible, and the liner plate 20 is added. Further, the liner plates 20 are assembled alternately (staggered) so that the shaft joints do not pass in the vertical direction so that the overall strength is not reduced. The upper shaft 12 is formed by the above operation.

  Next, the blocks of the intermediate support 30 are arranged in a ring shape on the bottom of the upper shaft 12, and these are assembled with bolts and nuts and connected to the upper shaft 12. The ground below the hole of the intermediate support 30 is dug by about 1 to 3 rings of the liner plate, and the liner plate 22 is assembled into a cylindrical shape in this hole and connected to the intermediate support 30.

  After assembling the liner plate 22, check the level and roundness of the liner plate 22, insert the mortar between the intermediate support 30 and the liner plate 22 and the ground 24, and back up the liner plate 22. Fix the edge to the surrounding ground. The mortar is drilled in the lowermost ring of the upper shaft 12 on site, or is injected from the inside of the shaft to the ground 24 side using an open liner plate.

  Next, the lower hole of the liner plate 22 is drilled further downward, and the liner plate 22 is added further downward. Also here, in order to prevent the collapse of the natural ground 24, the hole is not excavated too much, but the hole is excavated as much as possible, and the liner plate 22 is added in the same manner as the upper shaft. The lower shaft 14 is formed by the above operation.

  In the above description, the upper support 28 and the intermediate support 30 are assembled by bolts and nuts, but it is needless to say that these may be integrated by welding. Further, when the upper shaft 12 and the lower shaft 14 have the same diameter, the shaft can be formed only by the upper support 28.

  Although one embodiment of the present invention has been described above, the upper support 28 and the intermediate support 30 do not necessarily have a circular donut shape, and are not limited to other shapes, for example, What is necessary is just a donut shape, such as an oval shape, a rectangle, and a square. That is, any shape corresponding to the shape of the upper shaft 12 or the lower shaft 14 may be used.

FIG. 1 is a schematic longitudinal sectional view of a liner plate shaft using an upper support and an intermediate support according to an embodiment of the present invention. FIG. 2 is a plan view of the upper support according to one embodiment of the present invention. FIG. 3 is an AA arrow view of FIG. 4 is a view taken in the direction of arrows BB in FIG. FIG. 5 is a plan view of an intermediate support according to an embodiment of the present invention. FIG. 6 is a CC arrow view of FIG. FIG. 7 is a DD arrow view of FIG. FIG. 8 is an explanatory view showing an example when the liner plate shaft according to one embodiment of the present invention is applied to an inclined ground. FIG. 9 is a schematic longitudinal sectional view showing an example of a conventional liner plate shaft used for foundation construction of a power transmission tower and its upper support and intermediate support.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vertical shaft 12 Upper shaft 14 Lower shaft 20 Liner plate 22 Liner plate 24 Ground mountain 28 Upper support 30 Intermediate support 32 Upper plate 34 Lower plate 36 Connecting member 38 Water shielding plate 40 Vertical member 42 Bottom member 44 Oblique side member 46 Upper plate 48 Below Plate 52 Back plate 54 End stiffening plate 56 Intermediate stiffening plate 58 Circumferential stiffening plate

Claims (3)

  A step of connecting the liner plate in a ring shape in a shallow hole at the top of the shaft, and an upper edge portion of the liner plate connected to the ring shape while being connected to the liner plate connected to the ring shape on the ground Assembling the upper support and forming a shaft by adding a liner plate to the lower part of the ring-shaped liner plate while excavating the lower part of the liner plate connected to the ring. The support includes a donut-shaped upper plate, a donut-shaped lower plate provided coaxially and in parallel at a predetermined interval below the upper plate, and a plurality of connecting members that connect the upper plate and the lower plate. And the upper plate and the lower plate have an inner diameter substantially equal to the outer diameter of the liner plate shaft to be supported. Method.   2. The method for forming a liner plate shaft according to claim 1, further comprising the step of adding a liner plate to an upper edge portion of a ring-shaped liner plate connected to the upper support.   Assembling an intermediate support at a position laterally offset from the center of the bottom of the shaft, and adding a liner plate to the intermediate support in a ring shape while excavating below the intermediate support, Comprises a donut-shaped upper plate, a donut-shaped lower plate provided coaxially and parallelly below the upper plate at a predetermined interval, and a plurality of connecting members for connecting the upper plate and the lower plate. The upper plate and the lower plate have an outer diameter substantially equal to one liner plate shaft formed above, and an outer diameter of another liner plate shaft formed below the one liner plate shaft 3. The method for forming a liner plate shaft according to claim 1, wherein a ring-shaped circumferential stiffening plate is provided on the lower plate coaxially with the inner circumference of the lower plate. .

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