Steel tower foundation structure, method for constructing steel tower foundation, and jig used in constructing steel tower foundation

Abstract

To provide a steel tower foundation structure capable of ensuring the strength of a pile against a large load acting on the pile when the load increases due to an increase in the size of the steel tower, a method for constructing the steel tower foundation, and a jig used in constructing the steel tower foundation.SOLUTION: A steel tower foundation 10 comprises a pile 28 that is buried in the installation ground 26, with a portion of a pile head 28A provided on an inner periphery of the lowest outer piece 32 in the height direction of a steel tower 12, and an inner piece 30 disposed on an upper surface 28A1 of the pile head 28A.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tower foundation structure, a tower foundation construction method, and a jig used for constructing a tower foundation. [Background technology]

[0002] The following Patent Document 1 describes an invention related to a steel tower foundation structure. In this steel tower foundation structure, a precast concrete member constituting part of the foundation is placed on the installation surface of the pile head of a pile buried in the installation ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-094457 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned prior art, when the load acting on the pile increases due to an increase in the size of the steel tower, etc., there is room for improvement in terms of ensuring the strength of the pile against this load.

[0005] In consideration of the above-mentioned facts, the present invention aims to provide a tower foundation structure, a tower foundation construction method, and a jig for use in constructing a tower foundation that can ensure the strength of the piles against larger loads acting on the piles when the loads increase due to the enlargement of the tower, etc. [Means for solving the problem]

[0006] The tower foundation structure of the first aspect comprises a leg member that forms part of the steel leg of the tower, an inner piece made of precast concrete that is integral with the lower end of the leg member on the lower side in the height direction of the tower, an outer piece made of precast concrete that is arranged on the outer periphery of the inner piece with a gap between it and the outer surface of the inner piece and capable of supporting pressure from the inner piece side, and that is arranged in a row in the height direction, an intervening part made of concrete that is interposed between the inner piece and the outer piece and is arranged in close contact with the inner piece and the outer piece, and a pile that is buried in the installation ground, with a part of the pile head located on the inner periphery of the lowest outer piece in the height direction, and the inner piece being arranged on the upper surface of the pile head.

[0007] According to the first aspect of the tower foundation structure, an inner piece made of precast concrete is integrally formed with the lower end portion of the leg member that constitutes part of the steel frame leg of the tower, on the lower side in the height direction of the tower (hereinafter simply referred to as the height direction).

[0008] In addition, multiple outer pieces made of precast concrete are arranged in a row in the vertical direction on the outer periphery of the inner piece, with a gap between them and the outer periphery of the inner piece, and these outer pieces are capable of supporting pressure from the inner piece side.

[0009] Between the inner piece and the outer piece, there is a concrete interposition part that is in close contact with the inner piece and the outer piece. Therefore, when a lifting load caused by electric wires suspended from the tower is transmitted to the inner piece via the leg member, pressure acts from the inner piece to the outer piece via the interposition part. This pressure can be supported by the outer piece, so in this embodiment, the tower can be supported in a stable state.

[0010] In this embodiment, the inner piece is disposed on the top surface of the pile head of the pile buried in the installation ground, and the pile is subjected to a load from above in the height direction, i.e., a compressive load, via the leg member. If the steel tower becomes large, the pile may be compressed by the compressive load and may collapse.

[0011] In this embodiment, a part of the pile head is provided on the inner periphery side of the lowest outer piece in the height direction, so that the outer piece can support the compressive load acting on the pile and suppress the impact of the compressive load on the pile.

[0012] The second aspect of the tower foundation structure is the tower foundation structure of the first aspect, wherein the outer pieces are cylindrical with their axial direction being the height direction, and a plurality of box sections opening radially inward of the outer pieces are arranged along the circumferential direction of the outer pieces directly above the upper surface of the inner circumferential surface of the lowest outer piece.

[0013] According to the tower foundation structure of the second aspect, the outer piece is cylindrical with the axial direction being the height direction. Also, a plurality of box sections that are open radially inward of the outer piece are arranged along the circumferential direction of the outer piece directly above the top surface of the pile head on the inner circumferential surface of the lowest outer piece among the outer pieces arranged in a row in the height direction.

[0014] Therefore, when pouring the ready mixed concrete to form the pile head into the inner circumference of the lowest outer piece, the multiple boxes can be used to support a jig or the like that holds down the ready mixed concrete from above in the height direction, making it easier to position the top surface of the pile head in a specified position.

[0015] A method for constructing a steel tower foundation according to a third aspect includes driving a cylindrical standpipe into an installation ground, excavating the inside of the standpipe, driving a cylindrical casing into an inner periphery of the standpipe, excavating the inside of the casing, arranging a reinforcing bar cage inside the casing, injecting a first ready mixed concrete into the casing while pulling out the casing, arranging a disk-shaped jig at a location on the inner periphery of an outer piece made of cylindrical precast concrete at a predetermined distance from a lower end surface of the outer piece, and positioning the outer piece between the main pile reinforcement of the reinforcing bar cage and the standpipe. a second ready mixed concrete is filled on the inner side of the outer piece below the jig, a third ready mixed concrete is filled between the inner surface of the stand pipe and the outer surface of the outer piece while the stand pipe is pulled up, the jig is removed from the first ready mixed concrete and the concrete after the second ready mixed concrete has solidified, an inner piece made of precast concrete which is integral with the lower end of a leg member that constitutes part of the steel leg of a steel tower is placed on the concrete, and a fourth ready mixed concrete is poured between the inner piece and the outer piece.

[0016] According to the method for constructing a steel tower foundation according to the third aspect, the main part of the pile is formed by the first ready-mixed concrete injected into the casing driven into the inner periphery of the standpipe driven into the installation ground. After the casing is pulled out, the outer piece is placed on the first ready-mixed concrete so as to be located between the pile main reinforcement of the reinforcing cage integrated with the first ready-mixed concrete and the standpipe. At this time, a disk-shaped jig is placed on the inner periphery of the outer piece, and this jig is placed at a predetermined distance from the upper surface of the first ready-mixed concrete. Then, the second ready-mixed concrete is filled into the inner periphery of the outer piece below the jig, so that a part of the pile head is formed on the inner periphery of the outer piece.

[0017] In addition, by filling the space between the inner surface of the stand pipe and the outer surface of the outer piece with third ready mixed concrete while pulling up the stand pipe, filling is performed between the outer surface of the outer piece and the installation ground.

[0018] Then, the jig is removed from the pile head formed by the solidification of the first and second ready mixed concrete, and the inner piece which is integral with the lower end of the leg member is placed on the pile head, and a fourth ready mixed concrete is poured between the inner piece and the outer piece to form the tower foundation.

[0019] As described above, the tower foundation constructed by the tower foundation construction method according to this aspect has the same actions and effects as the first aspect described above.

[0020] The jig used for constructing a tower foundation in the fourth aspect has a disk-shaped main body portion having a circular outer periphery when viewed from the thickness direction and a first penetration portion provided in the center, a contact plate portion which is removably attached to the underside of the main body portion, is composed of a plurality of wooden boards, and is disk-shaped having a circular outer periphery larger than the outer periphery of the main body portion when viewed from the thickness direction and a second penetration portion which fits into the first penetration portion when viewed from the center, and a plurality of movable parts which are arranged on the upper surface of the main body portion along the circumferential direction of the main body portion and which are capable of taking a first state in which the tip portion is located radially outside the outer periphery of the contact plate portion when viewed from the thickness direction, and a second state in which the tip portion is located radially inside the outer periphery.

[0021] According to a fourth aspect of the jig for constructing a steel tower foundation (hereinafter, sometimes simply referred to as the jig), a disk-shaped main body part having a circular outer periphery as viewed in the thickness direction is provided, and a first penetration part is provided in the center of the main body part. Also, a contact plate part is removably attached to the lower surface of the main body part.

[0022] The contact plate portion is generally circular and has a larger outer periphery than the outer periphery of the main body portion when viewed in the thickness direction of the main body portion (hereinafter sometimes simply referred to as the thickness direction), and a second through portion that fits into the first through portion is provided in the center of this contact plate portion.

[0023] Meanwhile, on the upper surface of the main body, a plurality of movable parts are arranged along the circumferential direction (hereinafter sometimes simply referred to as the circumferential direction) of the main body. These movable parts can be in a first state in which the tip parts are located radially outward of the main body from the outer periphery of the contact plate part when viewed from the thickness direction, and in a second state in which the tip parts are located radially inward of the main body from the outer periphery. Note that, hereinafter, the radial direction of the main body may be simply referred to as the radial direction.

[0024] Therefore, for example, during construction of a tower foundation, a jig can be placed on the inner circumference of a cylindrical foundation component made of precast concrete that constitutes part of the tower foundation.

[0025] In detail, by inserting the jig into the inner periphery of the foundation component while setting the jig to the second state, the tip of the movable part can be engaged with a recess or the like provided on the inner periphery of the foundation component, thereby positioning the jig relative to the foundation component.

[0026] Then, the tremie pipe is inserted through the first penetration portion and the second penetration portion to inject ready-mixed concrete for forming the pile, and the ready-mixed concrete can be filled below the jig inside the foundation constituent member.

[0027] Therefore, in a tower foundation constructed using the jig according to this embodiment, the pile head of the pile is surrounded by the foundation component. After the ready-mix concrete has solidified, the body is detached from the contact plate, and the jig is removed by peeling off the contact plate attached to the top surface of the pile head. In this embodiment, since the contact plate is made of multiple wooden boards, it is easier to remove the contact plate from the pile head than in a case where the contact plate is made of a single steel plate or the like.

[0028] The jig used for constructing a steel tower foundation according to the fifth aspect is the jig used for constructing a steel tower foundation according to the fourth aspect, wherein the movable part is plate-shaped with the circumferential direction being the plate thickness direction and extending in the radial direction, and the thickness of the lower part of the part radially inward from the tip part becomes thinner toward the bottom, and further comprises a first locking part which is provided on the first penetration part side on the top surface and locks the movable part in the first state to limit the radially outward displacement of the movable part, and a second locking part which is provided on the outer periphery of the main body part on the top surface and locks the movable part in the first state so that it can swing in the circumferential direction.

[0029] According to the jig for constructing a steel tower foundation according to the fifth aspect, the movable part is formed in a plate shape whose thickness direction is the circumferential direction of the main body and which extends in the radial direction of the main body. Also, the thickness of the lower part of the part radially inward from the tip of the movable part becomes thinner toward the bottom.

[0030] Meanwhile, a first locking portion and a second locking portion are provided on the upper surface of the main body. The first locking portion is provided on the first penetrating portion side of the upper surface of the main body, and locks the movable portion when the jig is in the first state, thereby limiting radial outward displacement of the movable portion.

[0031] The second locking portion is provided on the outer circumferential side of the main body portion on the upper surface of the main body portion, and is locked to allow the movable portion to swing in the circumferential direction when the jig is in the first state.

[0032] Therefore, in this embodiment, for example, when the jig is placed on the inner periphery of the foundation constituent member in the first state and the foundation constituent member is placed on the pile, even if the main pile reinforcement comes into contact with the movable part, the movable part can oscillate in the circumferential direction to absorb the main pile reinforcement.

[0033] The jig used for constructing a steel tower foundation of the sixth aspect is the jig used for constructing a steel tower foundation of the fourth aspect, wherein the movable part is plate-shaped with the circumferential direction being the plate thickness direction and extending in the radial direction, and the part opposite the main body part at the inner end part on the radially inner side of the movable part is an extension part extending to the opposite side of the main body part in the thickness direction, and the radially outer peripheral part of the extension part has a downward slope from the radially inner side to the radially outer side when viewed from the circumferential direction.

[0034] According to the sixth aspect of the jig for constructing a steel tower foundation, the movable part is in the plate thickness direction (hereinafter may be simply referred to as the plate thickness direction) of the main body part in the circumferential direction, and is plate-shaped extending in the radial direction (hereinafter may be simply referred to as the radial direction) of the main body part. In addition, at the inner end part on the radially inner side of the movable part, the part opposite the main body part is an extension part that extends to the opposite side of the main body part in the thickness direction of the main body part. And, the peripheral part on the radially outer side of the extension part has a downward slope from the radially inner side to the radially outer side when viewed in the circumferential direction.

[0035] Therefore, in this aspect, for example, when the tip of the movable part is firmly engaged in a recess or the like provided on the inner surface of the base component in the first state of the jig, the engaged state between the tip of the movable part and the recess can be released by applying an impact force with a hammer or the like to the radially outer peripheral portion of the extension part.

[0036] The seventh aspect of the jig used for constructing a tower foundation is the same as the sixth aspect of the jig used for constructing a tower foundation, and further comprises an inner limiting portion that is provided on the first penetration portion side of the upper surface, limits the radially outward displacement of the movable portion in the first state, and is attached to the main body portion with a fastening member.

[0037] According to the seventh aspect of the jig used for constructing a steel tower foundation, an inner limiting portion is provided on the upper surface of the main body on the side of the first penetration portion. This inner limiting portion can limit the radially outward displacement of the movable portion. Therefore, in this aspect, in the first state of the jig, it is possible to prevent the tip of the movable portion from protruding radially outward more than necessary.

[0038] Incidentally, when the main body and the inner limiting portion are made of metal and the inner limiting portion is attached to the main body by welding, it is conceivable that the main body may become distorted due to heat or the like during welding.

[0039] Here, in this aspect, the inner limiting portion is attached to the main body portion by a fastening member, and by attaching the inner limiting portion to the main body portion, distortion of the main body portion can be suppressed.

[0040] The eighth aspect of the jig used for constructing a tower foundation is a jig used for constructing a tower foundation according to the seventh aspect, wherein the inner restriction portion comprises a pair of base portions arranged on the upper surface on one and the other circumferential sides of the movable portion and rising from the upper surface on the opposite side to the main body portion, and a spacer portion arranged on the opposite side of the main body portion of the movable portion, sandwiched between the pair of base portions, and having a circumferential thickness that is thicker than the circumferential thickness of the movable portion.

[0041] According to the eighth aspect of the jig for constructing a steel tower foundation, the inner limiting portion includes a pair of base portions and a spacer portion. The pair of base portions are disposed on one and the other circumferential sides of the movable portion on the upper surface of the main body portion, and rise from the upper surface on the opposite side to the main body portion.

[0042] On the other hand, the spacer portion is disposed on the opposite side of the main body portion in the movable portion and is sandwiched between the pair of base portions, and has a circumferential thickness greater than the circumferential thickness of the movable portion. This makes it possible to ensure a gap between the movable portion and the base portions in the circumferential direction, and as a result, in the first state of the jig, it is possible to adjust the circumferential position of the tip portion of the movable portion.

[0043] A jig used for constructing a tower foundation according to a ninth aspect is the jig used for constructing a tower foundation according to the eighth aspect, wherein the spacer portion is removably attached to the base portion.

[0044] According to the jig used for constructing a tower foundation of the ninth aspect, the spacer part is removably attached to the base part, and by removing the spacer part from the base part, the side of the movable part opposite the main body part in the thickness direction is opened.

[0045] Therefore, for example, when the tip of the movable part becomes stuck in a recess provided on the inner surface of the base component in the first state of the jig, the movable part can be removed from the recess by moving the movable part in the thickness direction.

[0046] The jig used for constructing a tower foundation in the tenth aspect is a jig used for constructing a tower foundation in the eighth or ninth aspect, wherein, when viewed from the circumferential direction, the spacer part has a semicircular peripheral portion on the side opposite the movable part that is convex toward the side opposite the movable part, and the peripheral portion on the movable part side is straight and extends along the movable part.

[0047] According to the jig used for constructing a steel tower foundation according to the tenth aspect, the peripheral portion of the spacer portion opposite the movable portion is semicircular and convex on the opposite side to the movable portion when viewed from the circumferential direction. Therefore, compared to a configuration in which this peripheral portion is rectangular and wavy and convex on the opposite side to the movable portion, when performing work to apply a striking force to the movable portion with a tool such as a hammer in the first state of the jig, it is possible to suppress the work from being hindered by the spacer portion.

[0048] In addition, when viewed from the circumferential direction, the peripheral edge of the spacer part on the movable part side is linearly extended along the movable part, thereby increasing the contact area of ​​the spacer part with the movable part and suppressing damage to the spacer part due to contact with the movable part.

[0049] The jig used for constructing a tower foundation in the eleventh aspect is a jig used for constructing a tower foundation in any one of the seventh to tenth aspects, further comprising an outer limiting part that is removably attached to the movable part and abuts against the inner limiting part to limit the radially inward displacement of the movable part.

[0050] According to the jig used for constructing a tower foundation in the 11th aspect, the outer limiting part is removably attached to the movable part, and this outer limiting part can be abutted against the inner limiting part to limit the radially inward displacement of the movable part.

[0051] Therefore, in this aspect, when the jig is in the first state, it is possible to restrict the movable part from being displaced radially inward. Also, by removing the outer restricting part from the movable part, it is possible to displace the movable part radially inward, and the jig can be put into the second state.

[0052] The jig used for constructing a tower foundation in accordance with the twelfth aspect is a jig used for constructing a tower foundation in accordance with any one of the sixth to eleventh aspects, wherein an interlocking portion is provided at the inner end portion.

[0053] According to the jig used for constructing a steel tower foundation of the twelfth aspect, an interlocking portion is provided at the inner end of the movable part, and a jig, tool, etc. can be interlocked with this interlocking portion. Therefore, in this aspect, for example, in the first state of the jig, when the tip end of the movable part is firmly interlocked with a recess or the like provided on the inner circumferential surface of the foundation constituent member, the movable part can be pulled radially inward via a jig, tool, etc. interlocked with the interlocking portion of the movable part. Effect of the Invention

[0054] As described above, the tower foundation structure, the tower foundation construction method, and the jig used in constructing the tower foundation of the present invention have the excellent effect of ensuring the strength of the piles against larger loads acting on the piles due to increases in the size of the tower, etc. [Brief description of the drawings]

[0055] [Figure 1] FIG. 2 is a cross-sectional view showing a schematic configuration of a foundation to which the tower foundation structure according to the first embodiment is applied. [Diagram 2] FIG. 2 is a perspective view showing a schematic configuration of an outer piece of a foundation to which the tower foundation structure according to the first embodiment is applied. [Diagram 3] FIG. 2 is a cross-sectional view showing a schematic configuration of an outer piece of a foundation to which the tower foundation structure according to the first embodiment is applied. [Figure 4] FIG. 1 is a side view showing a schematic configuration of a steel tower to which a steel tower foundation structure according to a first embodiment is applied. [Diagram 5] FIG. 2 is a cross-sectional view showing a schematic diagram of a first step in a construction process of a foundation pile to which the tower foundation structure according to the first embodiment is applied. [Figure 6] FIG. 4 is a cross-sectional view showing a schematic second step in the construction process of the foundation piles to which the tower foundation structure according to the first embodiment is applied. [Figure 7] FIG. 4 is a cross-sectional view showing a schematic diagram of a third step in the construction process of the foundation piles to which the tower foundation structure according to the first embodiment is applied. [Figure 8] FIG. 11 is a cross-sectional view illustrating a fourth step in the construction process of the foundation piles to which the tower foundation structure according to the first embodiment is applied. [Figure 9] FIG. 11 is a cross-sectional view showing a schematic diagram of a fifth step in the construction process of the foundation piles to which the tower foundation structure according to the first embodiment is applied. [Figure 10] FIG. 11 is a cross-sectional view illustrating a sixth step in the construction process of the foundation piles to which the tower foundation structure according to the first embodiment is applied. [Figure 11] FIG. 2 is a perspective view showing a schematic configuration of a jig used when constructing a pile of a foundation to which the tower foundation structure according to the first embodiment is applied. [Figure 12] FIG. 2 is a side view showing a schematic configuration of a movable part constituting a part of a jig used when constructing a pile of a foundation to which the tower foundation structure according to the first embodiment is applied. [Figure 13]FIG. 2 is a front view showing a schematic configuration of a first engaging portion and its surrounding portion that constitutes a part of a jig used when constructing a foundation pile to which the tower foundation structure according to the first embodiment is applied. [Figure 14] FIG. 11 is a front view showing a schematic configuration of a second engaging portion and its surrounding portion that constitute a part of a jig used when constructing a foundation pile to which the tower foundation structure according to the first embodiment is applied. [Figure 15] FIG. 2 is a front view showing a schematic configuration of a tip end of a movable part constituting a part of a jig used when constructing a pile of a foundation to which the tower foundation structure according to the first embodiment is applied. [Figure 16] FIG. 11 is a perspective view showing a schematic configuration of a jig used when constructing a pile of a foundation to which a steel tower foundation structure according to a second embodiment is applied. [Figure 17] FIG. 11 is a side view showing a schematic configuration of a movable part constituting a part of a jig used when constructing piles for a foundation to which a steel tower foundation structure according to a second embodiment is applied. [Figure 18] FIG. 11 is a front view showing a schematic configuration of a movable part constituting a part of a jig used when constructing piles for a foundation to which a steel tower foundation structure according to a second embodiment is applied. [Figure 19] FIG. 11 is a cross-sectional view illustrating a fifth step in the construction process of the foundation piles to which the tower foundation structure according to the second embodiment is applied. [Figure 20] FIG. 11 is a cross-sectional view showing a schematic diagram of a part of a seventh step in a construction process of a foundation pile to which the tower foundation structure according to the second embodiment is applied. [Figure 21] FIG. 11 is a cross-sectional view showing a schematic diagram of a part of a seventh step in a construction process of a foundation pile to which the tower foundation structure according to the second embodiment is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0056] First Embodiment Hereinafter, a tower foundation structure, a tower foundation construction method (construction method), and a jig used in constructing the tower foundation according to a first embodiment of the present invention will be described with reference to Figs.

[0057] As shown in Fig. 4, a "tower 12" equipped with a "tower foundation 10 (hereinafter simply referred to as foundation 10)" to which the tower foundation structure according to this embodiment is applied is configured to include a plurality of main pillar members 14, a plurality of horizontal members 16, a plurality of diagonal members 18, and a plurality of main pillar member auxiliary members 20 that are bridged between the main pillar members 14 and the diagonal members 18, and is equipped with four steel frame legs 22. In the following, unless otherwise specified, the height direction of the tower 12 will be simply referred to as the height direction. Furthermore, the height direction of the tower 12 coincides with the vertical direction.

[0058] As shown in Figure 1, the foundation 10 supports "leg members 24" that constitute part of the steel frame leg 22 against "installation ground 26", and is composed of "piles 28", "inner pieces 30", "outer pieces 32", and "intervening parts 34".

[0059] 10, the pile 28 is buried in the installation ground 26 and is composed of a cylindrical main body 36 made of concrete extending in the height direction, and a "reinforcement cage 38" whose main part is buried in the main body 36. The reinforcement cage 38 includes a plurality of "pile main reinforcements 40" extending in the height direction and arranged on a circumference centered on the axis of the pile 28 as viewed from the height direction, and a plurality of hoops 42 arranged in the height direction and having an annular shape surrounding the plurality of pile main reinforcements 40 as viewed from the height direction.

[0060] The pile head 28A of the pile 28 is treated with concrete or mortar, and the top surface 28A1 is smoothed to a flat surface. A part of the pile main reinforcement 40 extends upward in the height direction from the top surface 28A1. The construction process of the pile 28 will be described later.

[0061] Returning to Fig. 1, the inner piece 30 is provided integrally with the "lower end 24A" on the lower side in the height direction of the leg member 24, and is placed directly or via a member on the upper surface 28A1 of the pile 28. This inner piece 30 is made of precast concrete, and is configured in the shape of a square pillar extending in the height direction.

[0062] More specifically, the inner piece 30 has a plurality of recesses 44 on its "outer peripheral surface 30A". The recesses 44 are formed in an annular shape along the circumferential direction of the outer peripheral surface 30A when viewed from the height direction, and a plurality of recesses 44 are arranged in the height direction. Note that the inner piece 30 is arranged inside the circumference where the pile main reinforcement 40 is arranged when viewed from the height direction.

[0063] Meanwhile, the leg member 24 is mainly formed by joining a main body 46 made of angle iron and a base 48 made of flat steel at a joint (not shown) by welding or the like. More specifically, a plurality of support plates 50 made of angle iron are attached to the main body 46 along its extension direction by mounting members (not shown).

[0064] The outer piece 32 is made of precast concrete, and is configured in a cylindrical shape with its axial direction as the height direction, as shown in Figures 2 and 3. The outer pieces 32 are arranged so as to surround the pile main reinforcement 40 and the leg members 24 when viewed from the height direction, and a plurality of the outer pieces 32 (two, as an example, in this embodiment) are arranged in a row in the height direction. In the following, unless otherwise specified, when viewed from the height direction, the direction approaching the leg members 24 with respect to the "outer peripheral surface 32C" of the outer piece 32 as a reference is referred to as the radial inner side, the direction away from the leg members 24 is referred to as the radial outer side, and the direction along the outer peripheral surface 32C is referred to as the circumferential direction.

[0065] Inside the outer piece 32, a plurality of hoop reinforcements 52 extending in an annular shape as viewed from the height direction are arranged in the height direction. This allows the outer piece 32 to support pressure from its inner periphery. These hoop reinforcements 52 are connected by vertical reinforcements (not shown) extending in the height direction. The hoop reinforcements 52 may also be spiral reinforcements.

[0066] Further, a plurality of recesses 54 are provided on the "inner peripheral surface 32A" of the outer piece 32. The recesses 54 are formed in an annular shape along the circumferential direction of the inner peripheral surface 32A when viewed from the height direction, and a plurality of recesses 54 are arranged in the height direction. Further, the cross-sectional shape of the recesses 54 when viewed from the circumferential direction of the inner peripheral surface 30A is an isosceles trapezoid that is expanded toward the leg member 24 side.

[0067] The interposed portion 34 is formed by filling concrete between the inner piece 30 and the outer piece 32, and is in close contact with the inner piece 30 and the outer piece 32. By filling the recess 44 of the inner piece 30 and the recess 54 of the outer piece 32 with concrete, protrusions 56 are formed on the outer piece 32 side and the inner piece 30 side of the interposed portion 34.

[0068] In this embodiment, concrete is poured between the outer peripheral surface 32C of the outer piece 32 and the pit wall 26A of the installation ground 26, thereby forming a filler portion 59.

[0069] 3, in this embodiment, a steel "box portion 58" is embedded in the recess 54 located at a position spaced a predetermined distance from the "lower end surface 32B" of the outer piece 32. In detail, as one example, the box portion 58 is a rectangular parallelepiped that is open radially inward, and a plurality of the box portions 58 (six as one example) are disposed at equal intervals in the circumferential direction.

[0070] In addition, the upper end of the box portion 58 is located at the lower end of the convex portion vertically above the recessed portion 54 in which the box portion 58 is arranged on the inner surface 32A of the outer piece 32, i.e., the portion between the recessed portions 54.

[0071] As described later, these box parts 58 are used to position jigs used in constructing the steel tower foundation. In this embodiment, by using these jigs, a part of the concrete constituting the pile 28 is filled on the inner periphery side of the outer piece 32 that is the lowest in the height direction, and a part of the pile head part 28A is provided on the inner periphery side of the outer piece 32 that is the lowest in the height direction. Also, the box part 58 is disposed directly above the upper surface 28A1 of the pile head part 28A.

[0072] (Actions and Effects of the Present Embodiment) Next, the operation and effects of this embodiment will be described.

[0073] In this embodiment, as shown in FIG. 1 , an inner piece 30 made of precast concrete is integrally formed with a lower end portion 24A on the lower side in the height direction of a leg member 24 that constitutes part of a steel frame leg 22 of a steel tower 12.

[0074] In addition, multiple outer pieces 32 made of precast concrete are arranged in a row in the vertical direction on the outer circumferential side of the inner piece 30, at a distance from the outer circumferential surface 30A of the inner piece 30, and these outer pieces 32 are capable of supporting pressure from the inner piece 30 side.

[0075] Between the inner piece 30 and the outer piece 32, there is interposed an interposed portion 34 made of concrete, which is provided in close contact with the inner piece 30 and the outer piece 32. Therefore, when a lifting load or the like caused by electric wires or the like suspended from the steel tower 12 is transmitted to the inner piece 30 via the leg member 24, pressure acts from the inner piece 30 side to the outer piece 32 side via the interposed portion 34. This pressure can be supported by the outer piece 32, so in this embodiment, the steel tower 12 can be supported in a stable state.

[0076] In this embodiment, the inner piece 30 is disposed on the upper surface 28A1 of the pile head 28A of the pile 28 buried in the installation ground 26, and a load, i.e., a compressive load, acts on the pile 28 from above in the height direction via the leg member 24. If the steel tower 12 becomes large, it is considered that the pile 28 will be compressed by this compressive load and will become sagging.

[0077] In this embodiment, a part of the pile head 28A is provided on the inner periphery side of the lowest outer piece 32 in the height direction. Therefore, the compressive load acting on the pile 28 is supported by the outer piece 32, and the influence of this compressive load on the pile 28 can be suppressed.

[0078] In this embodiment, the outer piece 32 is cylindrical with the axial direction as the height direction, as shown in Fig. 2. In addition, as shown in Fig. 3, a plurality of box sections 58 that are open radially inward of the outer piece 32 are arranged along the circumferential direction of the outer piece 32 directly above the upper surface 28A1 of the pile head portion 28A on the inner circumferential surface 32A of the lowest outer piece 32 among the outer pieces 32 arranged in a row in the height direction.

[0079] Therefore, when pouring the ready mixed concrete for forming the pile head 28A into the inner peripheral side of the lowest outer piece 32, a jig or the like that holds down the ready mixed concrete from above in the height direction can be supported by using the multiple box parts 58. As a result, it becomes easy to position the upper surface 28A1 of the pile head 28A at a predetermined position.

[0080] Next, mainly using Figs. 5 to 10, an example of the procedure for constructing the foundation 10 to which the steel tower foundation structure according to this embodiment is applied will be described, mainly focusing on the method for constructing the piles 28.

[0081] 5, a cylindrical "standpipe 60" is driven into the installation ground 26, and the inside of the standpipe 60 is excavated with a hammer grab or the like (not shown). The installation depth Y [m] of the standpipe 60 from the ground surface 26B is calculated by the following formula (A).

[0082]

number

[0083] In this embodiment, the installation depth Y of the stand pipe 60 and various values ​​related to the installation depth Y are, for example, values ​​shown in the following table.

[0084] [Table 1]

[0085] 6, a cylindrical "casing 62" having a smaller diameter than the standpipe 60 is driven into the inside of the standpipe 60, and excavation inside the casing 62 is repeated. Then, when the tip of the casing 62 at the deepest position among the casings 62 connected in the vertical direction reaches the set pile tip depth, the reinforcing bar cage 38 is installed inside the casing 62.

[0086] 7, the tremie pipe 64 is inserted to the deepest part of the casing 62 and "fresh concrete 66" is poured into the casing 62 as the first fresh concrete. At this time, the casing 62 and the tremie pipe 64 are pulled up according to the amount of fresh concrete 66 to be poured. Then, when the surface of the poured fresh concrete 66 reaches a predetermined position, the surface portion of the surface of the fresh concrete 66, i.e., slime 66A, is removed using a vacuum device or the like.

[0087] 8, the last casing 62 is slowly pulled out, and fresh concrete 66 is filled inside the lower part of the standpipe 60 in the height direction. At this time, if necessary, fresh concrete 66 is further injected into the standpipe 60 so that the pressure of the fresh concrete 66 from the tip of the standpipe 60 to the surface of the fresh concrete 66 and the water pressure of the groundwater from the tip depth of the standpipe 60 to the groundwater level X are in equilibrium. At this time, the water inside the standpipe 60 may be drained.

[0088] The reason for setting the installation depth Y of the stand pipe 60 as described above is to prevent groundwater from infiltrating into the fresh concrete 66 when the water inside the stand pipe 60 is removed in this process.

[0089] 9, it is confirmed whether the surface position of the fresh concrete 66 is the preset installation position (setting position) of the outer piece 32. At this time, if the surface position is not the installation position, a process such as adding or removing the fresh concrete 66 is performed so that the surface position becomes the installation position. Then, a disk-shaped "jig 68" is placed at a position on the inner circumferential surface 32A of the lower outer piece 32 at a predetermined distance from the lower end surface 32B, and this outer piece 32 is placed on the fresh concrete 66 so as to be located between the pile main reinforcement 40 and the stand pipe 60. Then, the upper outer piece 32 is placed above this outer piece 32.

[0090] Here, an example of the configuration of the jig 68 used in constructing the steel tower foundation according to this embodiment will be described.

[0091] 11, the jig 68 includes a steel "main body 70," a "contact plate 72" made of concrete formwork plywood, and a number of "movable parts 74." In more detail, the main body 70 is disk-shaped with a circular outer periphery, and is provided with a "penetration part 76" as a first penetration part at the center when viewed in the plate thickness direction.

[0092] The contact plate portion 72 is generally circular with an outer periphery larger than the outer periphery of the main body portion 70 as viewed in the thickness direction of the main body portion 70, and is disk-shaped with a "through portion 78" provided in the center as a second through portion that fits into the through portion 76. Also, the contact plate portion 72 is divided along two straight lines that pass through its center and intersect at right angles at the center as viewed in the thickness direction, in other words, the contact plate portion 72 is composed of four roughly fan-shaped plywood sheets for concrete formwork.

[0093] The through portion 78 is sized to allow the insertion of the tremie tube 64. The contact plate portion 72 is removably attached to the lower surface of the main body portion 70 by a mounting member such as a bolt (not shown).

[0094] 12, a plurality of movable parts 74 (six, for example) are arranged on the upper surface 70A of the main body 70 at equal intervals in the circumferential direction of the main body 70. The movable part 74 includes a main plate 80 that constitutes the main part of the movable part 74, and a stopper plate 82.

[0095] The main plate 80 has a rectangular plate shape whose thickness direction is the circumferential direction of the main body portion 70 and extends in the radial direction of the main body portion 70. More specifically, as shown in Fig. 15, the thickness of the lower portion of the main plate 80 on the radially inner side of the main body portion 70 relative to the "tip portion 80A" on the outer periphery of the main body portion 70 becomes thinner toward the bottom, and the lower end of this portion has a curved surface shape that is convex downward when viewed from the extension direction of the main plate 80. In the following, this portion will be referred to as a tapered portion 80C.

[0096] On the other hand, the stopper plate 82 has a thickness direction that is the radial direction of the main body 70 and is a rectangular plate extending in the thickness direction of the main body 70, and is joined to a base end 80B of the main plate 80 on the side of the through portion 76 of the main body 70 at a joint (not shown) by welding or the like. Note that the length of the stopper plate 82 is set to be slightly longer than the length of the main plate 80 in the thickness direction of the main body 70 as shown in Fig. 13, and the width of the stopper plate 82 is set to be about three times the thickness of the main plate 80.

[0097] Returning to Fig. 11, the movable portion 74 is locked to a "locking plate 84" serving as a first locking portion and a "locking plate 86" serving as a second locking portion. In detail, the locking plate 84 is disposed on the side of the through portion 76 on the upper surface of the main body portion 70, and has a rectangular plate shape with the plate thickness direction being the radial direction of the main body portion 70. The thickness of the locking plate 84 is set to a thickness that allows it to fit into a slit portion 88 provided in a portion of the upper edge portion of the main plate 80 on the base end portion 80B side (see Fig. 12).

[0098] 13, the locking plate 84 is formed with a rectangular through-hole 90 whose longitudinal direction is the thickness direction of the main body 70 when viewed from the radial direction of the main body 70. The through-hole 90 is set to a size that allows the main plate 80 to pass therethrough but does not allow the stopper plate 82 to pass therethrough, and the main plate 80 is inserted into the through-hole 90 from the through-hole 76 side of the main body 70.

[0099] Returning to FIG. 11, the locking plate 86 is disposed on the outer periphery of the upper surface of the main body 70, and has a rectangular plate shape with its thickness direction aligned with the radial direction of the main body 70.

[0100] 14, the locking plate 86 is formed with a rectangular through-hole 92 whose longitudinal direction is the thickness direction of the main body 70 as viewed from the radial direction of the main body 70 and whose length in the direction perpendicular to the thickness direction is about twice the diameter of the pile main reinforcement 40. The main plate 80 is inserted into the through-hole 92 from the through-hole 76 side of the main body 70.

[0101] In the jig 68 configured as described above, the movable portion 74 is capable of assuming a first state in which, when viewed from the thickness direction of the main body portion 70, the tip portion 80A of the main plate 80 is positioned radially outside the main body portion 70 relative to the outer periphery of the contact plate portion 72, and a second state in which the tip portion 80A is positioned radially inside the outer periphery.

[0102] In the first state, the stopper plate 82 of the movable part 74 is locked to the locking plate 84, thereby restricting the displacement of the movable part 74 radially outward from the body part 70. Furthermore, in the first state, the main plate 80 of the movable part 74 is locked to the locking plate 86 so as to be swingable in the circumferential direction of the body part 70.

[0103] Therefore, in this embodiment, by inserting the jig 68 into the inner side of the outer piece 32 in the second state and also placing the jig 68 in the first state, the tip portion 80A of the movable portion 74 can be engaged with the box portion 58 provided on the inner surface 32A of the outer piece 32, thereby positioning the jig 68 relative to the outer piece 32.

[0104] In this embodiment, the upper end of the box portion 58 is located at the lower end of the convex portion on the upper side in the height direction of the recess 54 in which the box portion 58 is arranged on the inner circumferential surface 32A of the outer piece 32. This makes it easy to check the position of the box portion 58 when viewed from above in the height direction. Also, an allowance for the tip portion 80A of the main plate 80 of the jig 68 to be engaged is ensured, making it easier for the jig 68 to support the pressure acting by the ready-mixed concrete 94.

[0105] In addition, in this embodiment, when the jig 68 is in the first state and positioned on the inner periphery of the outer piece 32, and the outer piece 32 is placed on the fresh concrete 66, even if the pile main reinforcement 40 comes into contact with the tapered portion 80C of the movable part 74, the movable part 74 can oscillate in the circumferential direction of the main body part 70 as shown in Figure 15, thereby accommodating the pile main reinforcement 40.

[0106] Returning to the explanation of the method for constructing the tower foundation structure, as shown in Figure 9, in the fifth step, after the outer piece 32 is placed on the ready mixed concrete 66, the tremie pipe 64 is inserted into the penetration portion 78 of the jig 68, and "ready mixed concrete 94" as the second ready mixed concrete is filled around the inner circumference of the outer piece 32 below the jig 68, and the tremie pipe 64 is then pulled out.

[0107] Next, in a sixth step shown in FIG. 10, while filling the space between the inner peripheral surface of the stand pipe 60 and the outer peripheral surface 32C of the outer piece 32 with "ready-mixed concrete 96" as the third ready-mixed concrete, the stand pipe 60 is pulled up.

[0108] 1 and 10, the seventh step will be described. In the seventh step, the jig 68 is removed from the solidified concrete of the ready-mixed concrete 66 and the ready-mixed concrete 94, i.e., from the surface of the main body 36 of the pile 28, and the inner piece 30 is placed on the upper surface 28A1 of the pile 28, and the inner piece 30 is positioned so that the leg member 24 is located at a predetermined position. Furthermore, ready-mixed concrete is filled between the inner piece 30 and the outer piece 32 to form the intermediate portion 34. The ready-mixed concrete used to form the intermediate portion 34 functions as a fourth ready-mixed concrete in this embodiment.

[0109] In this embodiment, since the contact plate portion 72 of the jig 68 is made up of multiple plywood panels for concrete formwork, the contact plate portion 72 can be easily removed from the pile head portion 28A compared to a configuration in which the contact plate portion 72 is made up of a single steel plate or the like.

[0110] As described above, according to the foundation 10 to which the tower foundation structure of this embodiment is applied, the tower foundation construction method, and the jig 68 used in constructing the tower foundation, when the load acting on the pile 28 increases due to an increase in size of the tower 12, etc., the strength of the pile 28 against this load can be ensured.

[0111] <Second embodiment> 16 to 21, a "tower foundation 100 (hereinafter simply referred to as the foundation 100)" to which a tower foundation structure according to the second embodiment of the present invention is applied, and a "jig 102" used in constructing the foundation 100 will be described. Note that the same components as those in the above-mentioned first embodiment are given the same reference numerals and their description will be omitted.

[0112] Although foundation 100 according to this embodiment (see FIG. 21) has a configuration basically similar to foundation 10 according to the first embodiment, the configuration of jig 102 according to this embodiment is significantly different from jig 68 according to the first embodiment, and accordingly the configuration of foundation 100 is also partially changed from foundation 10. Therefore, the following description will mainly focus on the configuration of jig 102.

[0113] As shown in FIG. 16, the jig 102 includes a main body portion 70, a "contact plate portion 104", a plurality of "movable portions 106", and an "inner limiting portion 108" provided for each of the movable portions 106.

[0114] The contact plate portion 104 is configured by stacking three plate materials 110 made of concrete formwork plywood in the circumferential direction of the main body portion 70 and a plurality of plate materials 110 stacked in the thickness direction of the main body portion 70. The plate materials 110 may be made of polystyrene foam or the like.

[0115] In addition, the main body portion 70 and the plate material 110 have multiple through-holes (not shown), and a through-bolt 112 is inserted into these through-holes from the lower height side of the contact plate portion 104, and a nut 114 is fastened to the bolt 112 from the upper height side of the main body portion 70, thereby integrating the main body portion 70 and the contact plate portion 104.

[0116] In addition, the contact plate portion 104 configured as described above is generally circular in shape with an outer periphery larger than the outer periphery of the main body portion 70 when viewed in the thickness direction of the main body portion 70, and is disc-shaped with a "penetration portion 116" as a second penetration portion in the center, which is sized to allow the tremie tube 64 that fits into the penetration portion 76 to be inserted therethrough.

[0117] A plurality of movable parts 106 (six, for example) are arranged at equal intervals in the circumferential direction of the main body part 70 on the upper surface 70A of the main body part 70. The movable parts 106 are generally in the form of a rectangular plate whose thickness direction is the circumferential direction of the main body part 70 and which extends in the radial direction of the main body part 70.

[0118] More specifically, as shown in FIG. 17, the upper vertical portion (opposite the main body portion 70) of the "inner end portion 106A" radially inward of the main body portion 70 of the movable part 106 is formed as an "extension portion 106B" extending upward in the vertical direction.

[0119] The extension portion 106B has a triangular shape that is wider from the upper side in the height direction toward the lower side in the height direction when viewed in the circumferential direction of the main body portion 70. When viewed in the circumferential direction of the main body portion 70, a "peripheral edge portion 106B1" of the extension portion 106B on the radially outer side of the main body portion 70 has a downward slope from the radially inner side of the main body portion 70 toward the radially outer side.

[0120] In addition, the vertically lower peripheral edge of the radially outer "tip portion 106C" of the main body portion 70 of the movable part 106 is located vertically higher than the vertically lower peripheral edge of the radially inner portion of the tip portion 106C of the movable part 106, similar to the main plate 80.

[0121] Further, a "through portion 118" is formed on the inner end portion 106A of the movable portion 106 as a locked portion that penetrates the main body portion 70 in the circumferential direction. Note that a stud bolt or the like may be provided on the inner end portion 106A of the movable portion 106 instead of the through portion 118.

[0122] On the other hand, the inner limiting portion 108, as shown in FIG. 18, includes a pair of "base portions 120" and a "spacer portion 122."

[0123] Specifically, the base portion 120 is disposed on one side and the other side of the main body portion 70 in the movable portion 106 in the circumferential direction. The base portion 120 is made of steel and includes a plate-shaped fixed piece portion 120A disposed along the upper surface 70A of the main body portion 70 and having the plate thickness direction as the height direction, and a rising piece portion 120B extending upward in the height direction from the peripheral portion of the fixed piece portion 120A on the movable portion 106 side. That is, the rising piece portion 120B is in a state of rising on the opposite side to the main body portion 70 with respect to the upper surface 70A of the main body portion 70. The peripheral portion on the upper side in the height direction of the rising piece portion 120B is semicircular and convex upward in the height direction.

[0124] In addition, a through portion 124 is formed in the fixed piece portion 120A, and a through portion 126 corresponding to the through portion 124 is formed in the main body portion 70 in the radial direction of the main body portion 70, midway between the through portion 76 of the main body portion 70 and the outer peripheral edge portion 70B of the main body portion 70.

[0125] A "bolt 128" as a fastening member is inserted through the through-holes 124 and 126 from the lower side in the height direction of the main body 70, and a "nut 130" as a fastening member is fastened to the bolt 128 from the upper side in the height direction of the fixed piece portion 120A, thereby attaching the base portion 120 to the main body 70. Note that rivets or the like may be used to attach the base portion 120 to the main body 70.

[0126] The spacer portion 122 is disposed on the upper side in the height direction of the movable portion 106 (on the opposite side of the movable portion 106 from the main body portion 70) and is sandwiched between a pair of rising pieces 120B. The spacer portion 122 is made of a steel material such that the circumferential thickness of the main body portion 70 is thicker than the circumferential thickness of the movable portion 106, more specifically, the thickness is about two to three times the thickness of the movable portion 106.

[0127] When viewed from the circumferential direction of the main body 70, the spacer 122 has a "peripheral portion 122A" on the upper side in the height direction (opposite the movable portion 106) that is semicircular and convex upward in the height direction. When viewed from the circumferential direction of the main body 70, the peripheral portion 122B on the radially outer side of the main body 70 and the peripheral portion 122C on the radially inner side of the spacer 122 have linear shapes extending in the height direction.

[0128] When viewed from the circumferential direction of the main body 70, the "periphery 122D" on the lower side in the height direction of the spacer 122 is linear and extends along the radial direction (extension direction of the movable part 106) of the main body 70. That is, the shape of the spacer 122 when viewed from the circumferential direction of the main body 70 is a so-called semi-cylindrical shape.

[0129] The spacer portion 122 configured as described above has a through-hole 132 formed in its center, when viewed in the circumferential direction of the main body portion 70, which penetrates in the circumferential direction of the main body portion 70, and a through-hole 134 corresponding to the through-hole 132 is formed in the rising piece portion 120B.

[0130] The spacer portion 122 is disposed such that a peripheral edge 122A of the spacer portion 122 coincides with a peripheral edge on the upper side in the height direction of the rising piece portion 120B when viewed from the circumferential direction of the main body portion 70. A bolt 136 is inserted from one circumferential side of one rising piece portion 120B in the circumferential direction of the main body portion 70 through the through portion 132 and the through portion 134, and a nut 138 is fastened to the bolt 136 from the other circumferential side of the rising piece portion 120B in the other circumferential direction, thereby attaching the spacer portion 122 to the pair of base portions 120.

[0131] Further, a through-hole 140 is formed in a portion of the main body 70 that is radially outward of the inner limiting portion 108 in the movable part 106. A bolt 142 is inserted into the through-hole 140 from one circumferential side of the main body 70 in the movable part 106, and a nut 144 is fastened to the bolt 142 from the other circumferential side of the movable part 106.

[0132] The bolt 142 and the nut 144 are partially overlapped with the base portion 120 when viewed from the radial direction of the main body portion 70, and when the movable portion 106 is displaced radially inward, the bolt 142 and the nut 144 come into contact with the base portion 120. Hereinafter, the assembly of the bolt 142 and the nut 144 will be referred to as the "outer limiting portion 146."

[0133] In the jig 102 configured as described above, similarly to the jig 68, the movable part 106 is capable of assuming a first state in which the tip part 106C is positioned radially outside the main body part 70 relative to the outer periphery of the contact plate part 104 when viewed from the thickness direction of the main body part 70, and a second state in which the tip part 106C is positioned radially inside the outer periphery.

[0134] As shown in FIG. 16, eye nuts 148 used for moving the jig 102 are provided at multiple locations on the upper surface 70A of the main body 70.

[0135] On the other hand, as shown in FIG. 21, when using the jig 102 to construct the foundation 100, the pile main reinforcement 40 is divided into a lower reinforcement section 40A in which the pile 28 is mainly embedded, and an upper reinforcement section 40B in which the pile main reinforcement 40 is embedded in the intermediate section 34 (not shown in FIG. 21), and these are connected by a joint section 150.

[0136] Specifically, the lower reinforcement section 40A and the upper reinforcement section 40B are made of screw-knotted reinforcing bars and are connected directly above the upper surface 28A1 of the pile head 28A. That is, the upper end 40A1 in the height direction of the lower reinforcement section 40A is located directly above the upper surface 28A1, as shown in FIG.

[0137] (Actions and Effects of the Present Embodiment) Next, the operation and effects of this embodiment will be described.

[0138] 17, the movable part 106 is formed in a plate shape with the circumferential direction of the main body part 70 being the plate thickness direction and extending in the radial direction of the main body part 70. Also, at an inner end part 106A on the radially inner side of the main body part 70 in the movable part 106, a part opposite to the main body part 70 is formed as an extension part 106B extending to the opposite side of the main body part 70 in the thickness direction of the main body part 70. Also, a peripheral edge part 106B1 on the radially outer side of the main body part 70 of the extension part 106B has a downward slope from the radially inner side to the radially outer side as viewed in the circumferential direction of the main body part 70.

[0139] Therefore, in this embodiment, for example, when the tip portion 106C of the movable part 106 is firmly engaged with the box portion 58 (see Figure 3) provided on the inner surface 32A of the outer piece 32 in the first state of the jig 102, the engaged state between the tip portion 106C of the movable part 106 and the box portion 58 can be released by applying an impact force with a hammer or the like to the radially outer peripheral portion 106B1 of the main body portion 70 in the extension portion 106B.

[0140] In this embodiment, an inner limiting portion 108 is provided on the upper surface 70A of the main body portion 70 on the side of the through portion 76. This inner limiting portion 108 can limit the radial outward displacement of the main body portion 70 in the movable portion 106. For this reason, in this embodiment, in the first state of the jig 102, it is possible to prevent the tip portion 106C of the movable portion 106 from protruding radially outward from the main body portion 70 more than necessary.

[0141] Incidentally, when the main body portion 70 and the inner limiting portion 108 are made of metal and the inner limiting portion 108 is attached to the main body portion 70 by welding, it is conceivable that the main body portion 70 will be distorted by heat or the like during welding.

[0142] Here, in this embodiment, the inner limiting portion 108 is attached to the main body portion 70 with a bolt 128 and a nut 130, and by attaching the inner limiting portion 108 to the main body portion 70, distortion of the main body portion 70 can be suppressed.

[0143] 18, in this embodiment, the inner limiting portion 108 includes a pair of base portions 120 and a spacer portion 122. The pair of base portions 120 are disposed on one and the other circumferential sides of the main body portion 70 in the movable portion 106 on the upper surface 70A of the main body portion 70, and rise up from the upper surface 70A to the side opposite the main body portion 70.

[0144] On the other hand, the spacer portion 122 is disposed on the opposite side of the movable portion 106 to the main body portion 70 and is sandwiched between the pair of base portions 120, and the circumferential thickness of the main body portion 70 is greater than the circumferential thickness of the movable portion 106. For this reason, a gap can be secured between the movable portion 106 and the base portion 120 in the circumferential direction of the main body portion 70, and as a result, in the first state of the jig 102, the circumferential position of the tip portion 106C of the movable portion 106 can be adjusted.

[0145] Furthermore, in this embodiment, the spacer portion 122 is removably attached to the base portion 120, and by removing the spacer portion 122 from the base portion 120, the side of the movable portion 106 opposite the main body portion 70 in the thickness direction of the main body portion 70 is opened.

[0146] Therefore, for example, when the tip portion 106C of the movable portion 106 is fixed to the box portion 58 in the first state of the jig 102, the movable portion can be removed from the box portion 58 by moving the movable portion 106 in the thickness direction of the main body portion 70.

[0147] In addition, in this embodiment, when viewed from the circumferential direction of the main body 70, the peripheral portion 122A of the spacer portion 122 opposite the movable portion 106 is semicircular and convex on the side opposite the movable portion 106. For this reason, compared to a configuration in which this peripheral portion 122A is rectangular and wave-shaped and convex on the side opposite the movable portion 106, when performing an operation of applying a striking force to the extension portion 106B of the movable portion 106 with a tool such as a hammer in the first state of the jig 102, it is possible to suppress the operation from being hindered by the spacer portion 122.

[0148] In addition, when viewed from the circumferential direction of the main body 70, the peripheral edge 122D of the spacer part 122 on the movable part 106 side is linearly shaped extending along the movable part 106. This increases the contact area of ​​the spacer part 122 with the movable part 106, thereby preventing the spacer part 122 from being damaged by contact with the movable part 106.

[0149] In addition, in this embodiment, the outer limiting portion 146 is removably attached to the movable portion 106, and this outer limiting portion 146 abuts against the inner limiting portion 108, thereby limiting the radially inward displacement of the main body portion 70 in the movable portion 106.

[0150] For this reason, in this embodiment, when the jig 102 is in the first state, it is possible to restrict the movable part 106 from being displaced radially inward of the main body part 70. Moreover, by removing the outer limiting part 146 from the movable part 106, it becomes possible to displace the main body part 70 in the movable part 106 radially inward, and the jig 102 can be put into the second state.

[0151] Additionally, in this embodiment, a through-hole 118 that penetrates the main body 70 in the circumferential direction is formed at the inner end 106A of the movable part 106, and a part of a shackle or the like can be inserted into this through-hole 118. Therefore, in this aspect, for example, when the tip 106C of the movable part 106 is firmly locked to the box part 58 in the first state of the jig, the movable part 106 can be pulled radially inward of the main body 70 via a shackle or the like that is locked to the through-hole 118 of the movable part 106.

[0152] 19, in this embodiment, the pile main reinforcement 40 is divided into a lower reinforcement portion 40A and an upper reinforcement portion 40B, and in the fourth step, only the lower reinforcement portion 40A of the pile main reinforcement 40 can be buried in the fresh concrete 66. Therefore, when the last casing 62 is pulled out, the flow of the fresh concrete 66 is prevented from being hindered by a part of the pile main reinforcement 40, and the fresh concrete 66 can be smoothly filled inside the stand pipe 60.

[0153] In this embodiment, by using the jig 102 when constructing the foundation 100, the fifth step and part of the seventh step are modified from the steps of constructing the foundation 10.

[0154] Specifically, in the fifth step of this embodiment, after the jig 102 is placed on the outer piece 32, a part of the fresh concrete 66 adhering to the head of the lower reinforcement part 40A is wiped off with a rag or the like. At this time, when viewed from the radial direction of the main body part 70, the head of the lower reinforcement part 40A and the contact plate part 104 overlap each other.

[0155] Then, the tremie pipe 64 is inserted into the through portion 116 of the jig 102, and ready-mixed concrete 94 is filled into the inner peripheral side of the outer piece 32 below the jig 102, and the tremie pipe 64 is then pulled out.

[0156] 20 and 21, in the seventh step of this embodiment, the jig 102 is removed after the ready-mixed concrete 66 and the ready-mixed concrete 94 have solidified, and the inner piece 30 is placed on the upper surface 28A1 of the pile 28. Then, the upper reinforcement portion 40B is connected to the lower reinforcement portion 40A via the joint portion 150, and ready-mixed concrete is filled between the inner piece 30 and the outer piece 32 to form the interposed portion 34.

[0157] In this embodiment, by performing the construction process of the foundation 100 as described above, it is possible to prevent the positioning work of the inner piece 30 from being hindered by the pile main reinforcement bars 40.

[0158] <Supplementary explanation of the above embodiment> (1) In the above-described embodiment, two outer pieces 32 were arranged in the vertical direction. However, if the installation position of the leg member 24 is to be set deeper, additional outer pieces 32 may be added as appropriate.

[0159] (2) Furthermore, the steps of the method for constructing the foundation 10 and the foundation 100 according to the above-described embodiment are not limited to those described above. In other words, as long as the foundation 10 can be constructed, some of the steps may be interchanged, or some steps may be omitted depending on the condition of the installation ground 26, etc. [Explanation of symbols]

[0160] 10. Tower Foundation 12 Steel Tower 24 Leg material 24A Lower end 26 Installation ground 28 stake 28A Pile head 28A1 Top 30 Inner Piece 30A outer surface 32 Outer Piece 32A Inner surface 32B Lower end surface 32C Outer surface 34 Interposition part 38 Reinforced Concrete Cage 40 Pile main reinforcement 58 Box Section 60 Standpipe 62 Casing 66 Ready-mix concrete (first ready-mix concrete) 68 Jig 70 Main body 72 Contact plate part 74 Moving parts 76 Penetration (first penetration) 78 Penetration (Second Penetration) 80A tip 84 Locking plate (first locking portion) 86 Locking plate (second locking part) 94 Ready-mix concrete (second ready-mix concrete) 96 Ready-mix concrete (third ready-mix concrete) 100 Tower Foundation 102 Jig 104 Contact plate part 108 Inner Restriction 116 Penetration (Second Penetration) 118 Penetrating part (locked part) 120 Base 122 Spacer part 122A Periphery 122D Periphery 128 Bolt (fastening member) 130 Nut (fastening member) 146 Outer restriction section

Claims

1. A leg member that constitutes part of the steel leg of the steel tower; An inner piece made of precast concrete integrally provided with a lower end portion of the leg member on the lower side in the height direction of the steel tower; a plurality of outer pieces made of precast concrete arranged in a row in the height direction, the outer pieces being arranged on the outer periphery of the inner piece at a distance from the outer periphery of the inner piece and capable of supporting pressure from the inner piece side; an intervening portion made of concrete interposed between the inner piece and the outer piece and provided in close contact with the inner piece and the outer piece; A pile is buried in the installation ground, a part of the pile head is provided on the inner periphery side of the outer piece that is the lowest in the height direction, and the inner piece is arranged on the upper surface of the pile head; A steel tower foundation structure having the above structure.

2. The outer piece has a cylindrical shape with an axial direction being the height direction, a plurality of box portions that are open radially inward of the outer piece are disposed along a circumferential direction of the outer piece directly above the upper surface on an inner circumferential surface of the outer piece at the lowermost side; The tower foundation structure according to claim 1.

3. A cylindrical standpipe is driven into the installation ground and excavated inside the standpipe. A cylindrical casing is driven into the inner peripheral side of the standpipe and excavated inside the casing; A reinforcing bar cage is placed in the casing; The casing is pulled out while pouring a first ready-mixed concrete into the casing; A circular jig is disposed on an inner peripheral surface of a cylindrical outer piece made of precast concrete at a predetermined distance from a lower end surface of the outer piece; The outer piece is placed on the first ready-mixed concrete so as to be located between the pile main reinforcement of the reinforcing cage and the stand pipe; A second ready-mixed concrete is filled on the inner periphery side of the outer piece below the jig, The stand pipe is pulled up while filling a gap between the inner peripheral surface of the stand pipe and the outer peripheral surface of the outer piece with third ready mixed concrete. The jig is removed from the concrete after the first ready-mixed concrete and the second ready-mixed concrete have solidified, and an inner piece made of precast concrete is placed on the concrete, the inner piece being integral with a lower end of a leg member constituting a part of a steel leg of a steel tower; Pouring a fourth ready-mix concrete between the inner piece and the outer piece. How to construct a tower foundation.

4. A disk-shaped main body portion having a circular outer periphery when viewed in a thickness direction and a first through-hole provided at a center portion thereof; a contact plate portion that is removably attached to the underside of the main body portion, is made of a plurality of wooden boards, and is circular in shape with an outer periphery larger than the outer periphery of the main body portion as viewed from the thickness direction, and has a second penetration portion at its center that fits into the first penetration portion; a first state in which a tip portion is located radially outward of the main body portion relative to an outer periphery of the contact plate portion when viewed from the thickness direction, and a second state in which the tip portion is located radially inward of the outer periphery; A jig used in constructing a steel tower foundation having a

5. The movable portion is formed in a plate shape having a plate thickness direction in the circumferential direction and extending in the radial direction, and a thickness of a lower portion of a portion radially inward from the tip portion becomes thinner toward the bottom, a first locking portion that is provided on the upper surface on a side of the first penetrating portion and that locks the movable portion in the first state to limit displacement of the movable portion outward in the radial direction; a second locking portion that is provided on the upper surface on an outer circumferential side of the main body portion and that locks the movable portion to be swingable in the circumferential direction in the first state; Further comprising: A jig for use in constructing the tower foundation according to claim 4.

6. The movable portion is formed in a plate shape having a plate thickness direction in the circumferential direction and extending in the radial direction, A portion of the movable portion on the radially inner side of the inner end portion opposite to the main body portion is an extension portion extending to the opposite side of the main body portion in the thickness direction, and a peripheral portion of the extension portion on the radially outer side has a downward slope from the radially inner side to the radially outer side as viewed in the circumferential direction. A jig for use in constructing the tower foundation according to claim 4.

7. The upper surface is provided on the first penetrating portion side, and the inner limiting portion limits the radial outward displacement of the movable portion in the first state and is attached to the main body portion by a fastening member. A jig for use in constructing the tower foundation according to claim 6.

8. The inner limiting portion is a pair of base portions disposed on one and the other sides of the movable portion in the circumferential direction on the upper surface and rising from the upper surface to an opposite side to the main body portion; a spacer portion disposed on an opposite side of the movable portion to the main body portion, sandwiched between the pair of base portions, and having a thickness in the circumferential direction greater than a thickness in the circumferential direction of the movable portion; Equipped with A jig used for constructing the tower foundation according to claim 7.

9. The spacer portion is removably attached to the base portion. A jig used for constructing the tower foundation according to claim 8.

10. When viewed from the circumferential direction, the spacer portion has a semicircular periphery on a side opposite to the movable portion that is convex toward the side opposite to the movable portion, and the periphery on the movable portion side is linear and extends along the movable portion. A jig used for constructing the tower foundation according to claim 8.

11. The movable portion further includes an outer limiting portion that is removably attached to the movable portion and abuts against the inner limiting portion to limit the radially inward displacement of the movable portion. A jig used for constructing the tower foundation according to claim 7.

12. A locked portion is provided at the inner end portion. A jig for use in constructing the tower foundation according to claim 6.

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