JP6007863B2 - Joint structure of steel pipes constituting rotating piles - Google Patents

Joint structure of steel pipes constituting rotating piles Download PDF

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JP6007863B2
JP6007863B2 JP2013117462A JP2013117462A JP6007863B2 JP 6007863 B2 JP6007863 B2 JP 6007863B2 JP 2013117462 A JP2013117462 A JP 2013117462A JP 2013117462 A JP2013117462 A JP 2013117462A JP 6007863 B2 JP6007863 B2 JP 6007863B2
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謙治 河野
謙治 河野
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JFE Steel Corp
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本発明は、回転杭を構成する鋼管の接合構造に関するものである。   The present invention relates to a joining structure of steel pipes constituting a rotating pile.

土木構造物や建築構造物の基礎杭に用いられる鋼管杭工法のうち、回転杭工法の採用が近年増加している。
回転杭工法は、先端部に羽根や翼を取り付けた鋼管杭の杭体に回転トルクを伝達させて、地盤中に木ねじのように回転貫入させる工法であり、高いねじり耐力を有する鋼管杭特有の工法である。
この回転杭工法の回転トルクを伝達可能なねじり耐力を有する鋼管杭の接合構造としては、例えば特許文献１に提案されている「鋼管杭の接合構造」がある。
特許文献１の「鋼管杭の接合構造」は、「一対の鋼管杭を接合する構造において、第１鋼管杭の端部は、その軸線方向に突出するように周方向に間隔を隔てて形成された複数の凸部と、該複数の凸部の間に形成された複数の凹部とを有し、第２鋼管杭の端部は、前記第１鋼管杭の端部と補完的な形状を有し、前記第１鋼管杭の端部と前記第２鋼管杭の端部との嵌合状態において周方向に沿って隣接する凸部を互いに連結するための連結部材を備えていることを特徴とする」ものである（請求項１参照）。
そして、特許文献１においては、上・下杭のテーパ面（台形斜面）の当接により、ねじり耐力を確保することができるとされている。 Among steel pipe pile methods used for civil engineering structures and foundation piles for building structures, the adoption of rotary pile methods has been increasing in recent years.
The rotary pile construction method is a construction method in which rotational torque is transmitted to the pile body of a steel pipe pile with blades and wings attached to the tip, and it rotates and penetrates into the ground like a wood screw, which is unique to steel pipe piles with high torsional resistance. It is a construction method.
As a joining structure of steel pipe piles having torsional strength capable of transmitting the rotational torque of this rotating pile method, there is a “steel pipe pile joining structure” proposed in Patent Document 1, for example.
The "joint structure of steel pipe piles" in Patent Document 1 is "in the structure for joining a pair of steel pipe piles, the ends of the first steel pipe piles are formed at intervals in the circumferential direction so as to protrude in the axial direction thereof. A plurality of convex portions and a plurality of concave portions formed between the plurality of convex portions, and the end of the second steel pipe pile has a complementary shape to the end of the first steel pipe pile. And a connecting member for connecting the convex portions adjacent to each other along the circumferential direction in the fitted state between the end portion of the first steel pipe pile and the end portion of the second steel pipe pile. (See claim 1).
And in patent document 1, it is supposed that a torsional strength can be ensured by contact | abutting of the taper surface (trapezoid slope) of an upper and a lower pile.

特開２００４−５２３３３号公報JP 2004-52333 A

特許文献１では、凸部と凹部をテーパ面で当接させており、このテーパ面と周方向とのなす角度が、45°よりも大きくかつ85°よりも小さいことが好ましいとされている。
前記角度を45°よりも大きく設定した理由として、45°以下の場合にはねじり耐力の確保が困難となるためとしている。つまり、45°以下の角度が小さいテーパ面では、上杭に回転トルクを作用させたときに、上杭側の継手部がテーパ面を滑り上がろうとし、その力が円弧状帯部材や締結部材にせん断力として作用してしまうため、これを回避する必要があるということである。換言すれば、特許文献１では、テーパ面の角度を45°より大きくすることにより、回転トルクを、テーパ面の支圧又は台形状の凸部底面のせん断により伝達する構造としていることになる。
また、前記角度を85°よりも小さくした理由として、85°以上の場合にはテーパ面が嵌合案内として機能しにくくなるためとされている（特許文献１の段落［００２４］参照）。 In Patent Document 1, the convex portion and the concave portion are brought into contact with each other with a tapered surface, and the angle formed between the tapered surface and the circumferential direction is preferably larger than 45 ° and smaller than 85 °.
The reason why the angle is set larger than 45 ° is that it is difficult to ensure torsional strength when the angle is 45 ° or less. In other words, with a tapered surface with a small angle of 45 ° or less, when rotational torque is applied to the upper pile, the joint on the upper pile side tries to slide up the tapered surface, and that force is applied to the arc-shaped band member or fastening. This means that it is necessary to avoid this because it acts as a shearing force on the member. In other words, Patent Document 1 has a structure in which the rotational torque is transmitted by supporting the taper surface or shearing the bottom surface of the trapezoidal convex portion by making the angle of the taper surface greater than 45 °.
Further, the reason why the angle is made smaller than 85 ° is that when the angle is 85 ° or more, the tapered surface hardly functions as a fitting guide (see paragraph [0024] of Patent Document 1).

ここで、回転杭工法は原則として支持層へ1Dp以上根入れすることとされており、特に、地盤の硬さの指標であるN値が50以上の硬い支持層への貫入時においては、鋼管杭の全強ねじり耐力に比較的近い大きな回転トルクを作用させる必要がある。
しかしながら、台形状の凸部は上・下杭の継手部で周方向に沿って隣接しているため、上記せん断面として使えるのはそれぞれの継手部で周長の1/2しかない。さらに、せん断強度は引張強度の1/√3（≒0.58）倍まで低減されてしまう。
したがって、このような回転杭工法の大きな回転トルクに対応させるためには、どうしても継手の板厚や長さが大きくならざるを得ない、もしくは作用させる回転トルクに制限を設けざるを得ないという課題があった。 Here, as a general rule, the rotary pile method is to have a depth of 1 Dp or more in the support layer, especially when it penetrates into a hard support layer with an N value of 50 or more, which is an indicator of the hardness of the ground. It is necessary to apply a large rotational torque that is relatively close to the total torsional strength of the pile.
However, since the trapezoidal convex portions are adjacent in the circumferential direction at the joint portions of the upper and lower piles, only one-half of the circumferential length can be used as the shear surface. Furthermore, the shear strength is reduced to 1 / √3 (≈0.58) times the tensile strength.
Therefore, in order to cope with the large rotational torque of such a rotary pile method, the problem is that the thickness and length of the joint must be increased, or the rotational torque to be applied must be limited. was there.

また、特許文献１では、台形状の凸部は、上・下杭の継手部で同じ形状又は軸線方向に関して対称とされている。
ここで、鋼管杭を地盤中に回転貫入させるための回転方向（右回転と左回転）は、鋼管杭の先端部に取り付けた羽根の向きにより決まっており、一般に地盤に貫入していく方向を正回転、その逆を逆回転と言う。
正回転では、鋼管杭の先端部の羽根が地盤を掘削しながら回転貫入していくため、常に地盤からの抵抗を受ける。一方、逆回転は、杭を引き抜くため、又は杭の貫入性が悪くなった場合などに貫入性を回復させるために、鋼管杭を引き上げながら行うため、地盤からの抵抗はほとんどない。このように、羽根の地盤からの抵抗の有無の違いから、正回転時と逆回転時の回転トルクの大きさとしては、正回転の方が大きい。 Moreover, in patent document 1, the trapezoidal convex part is made symmetrical with respect to the same shape or axial direction at the joint part of the upper and lower piles.
Here, the rotation direction (right rotation and left rotation) for rotating and penetrating the steel pipe pile into the ground is determined by the direction of the blade attached to the tip of the steel pipe pile, and generally the direction to penetrate the ground Forward rotation and the reverse are called reverse rotation.
In the forward rotation, the blades at the tip of the steel pipe pile penetrate the rotation while excavating the ground, and therefore always receive resistance from the ground. On the other hand, since reverse rotation is performed while pulling up the steel pipe pile in order to pull out the pile or to recover the penetration when the penetration of the pile is deteriorated, there is almost no resistance from the ground. Thus, from the difference in presence or absence of resistance from the ground of the blade, the forward rotation is larger as the magnitude of the rotational torque during the forward rotation and the reverse rotation.

したがって、回転杭工法において作用する回転トルクに効率よく対応するには、接合構造は対称な形状である必要はなく、正回転時に逆回転時よりも大きな回転トルクを伝達可能な構造とすることが合理的である。
しかしながら、特許文献１では、台形状の凸部の形状に関し、軸線方向に関して対称としていることから、合理的な形状とは言い難い。
なお、特許文献１には、継手部及び凸部の形状については様々な変形例が可能とされているが、その具体的な例は明示されていない。 Therefore, in order to efficiently cope with the rotational torque acting in the rotary pile construction method, the joining structure does not have to be a symmetric shape, and a structure capable of transmitting a larger rotational torque at the time of forward rotation than at the time of reverse rotation. Is reasonable.
However, in Patent Document 1, it is difficult to say that the shape of the trapezoidal convex portion is a reasonable shape because it is symmetric with respect to the axial direction.
In Patent Document 1, various modifications can be made to the shapes of the joint portion and the convex portion, but specific examples thereof are not clearly shown.

本発明はかかる課題を解決するためになされたものであり、回転杭工法の大きな回転トルクに対応でき、回転杭の正回転、逆回転を考慮した合理的な回転杭を構成する鋼管の接合構造を提供することを目的としている。   The present invention was made in order to solve such a problem, and can be adapted to the large rotational torque of the rotary pile construction method, and the steel pipe joint structure that constitutes a rational rotary pile considering the normal rotation and reverse rotation of the rotary pile The purpose is to provide.

（１）本発明に係る回転杭を構成する鋼管の接合構造は、回転杭を構成する上下の鋼管を接合する接合構造であって、
下側の鋼管の上端に取り付けられた第１外側継手管と、上側の鋼管の下端に取り付けられた第２外側継手管と、前記第１外側継手管の上端面と前記第２外側継手管の下端面を当接させた状態で前記第１外側継手管と前記第２外側継手管の内周面側においてこれらを連結する内側継手部材とを備え、
前記第１外側継手管と前記第２外側継手管は、前記回転杭が正回転したときに両者が上下方向に離れる方向となる複数の螺旋斜面を有する接合端面を介して当接し、前記内側継手部材は前記第１外側継手管と前記第２外側継手管が離れようとするのに抵抗するようになっていることを特徴とするものである。 (1) The steel pipe joining structure constituting the rotating pile according to the present invention is a joining structure for joining the upper and lower steel pipes constituting the rotating pile,
A first outer joint pipe attached to the upper end of the lower steel pipe, a second outer joint pipe attached to the lower end of the upper steel pipe, an upper end surface of the first outer joint pipe, and the second outer joint pipe An inner joint member for connecting the first outer joint pipe and the second outer joint pipe on the inner peripheral surface side in a state where the lower end surface is in contact with each other;
The first outer joint pipe and the second outer joint pipe are in contact with each other through joint end surfaces having a plurality of spiral slopes that are separated in the vertical direction when the rotary pile rotates forward, and the inner joint The member is configured to resist the separation of the first outer joint pipe and the second outer joint pipe.

（２）また、上記（１）に記載のものにおいて、前記第１外側継手管は内周面に内方向に突出する第１凸部を有し、前記第２外側継手管は内周面に内方に突出する第２凸部を有し、前記内側継手部材は前記第１凸部と前記第２凸部に嵌合可能な凹部を有する複数の円弧状部材からなることを特徴とするものである。 (2) Further, in the above (1), the first outer joint pipe has a first convex portion projecting inward on the inner peripheral surface, and the second outer joint pipe is formed on the inner peripheral surface. A second convex portion projecting inward; and the inner joint member is composed of a plurality of arc-shaped members having concave portions that can be fitted to the first convex portion and the second convex portion. It is.

（３）また、上記（１）又は（２）に記載のものにおいて、前記第１外側継手管及び前記第２外側継手管の接合端面は、前記螺旋斜面に連続する支圧面を有し、
前記螺旋斜面の杭軸直角方向に対する傾斜角度をθ1、前記支圧面の杭軸直角方向に対する傾斜角度をθ2とすると、5°≦θ1≦45°、85°≦θ2≦90°に設定されていることを特徴とするものである。 (3) Moreover, in the above-mentioned (1) or (2), the joint end faces of the first outer joint pipe and the second outer joint pipe have a bearing surface that is continuous with the spiral slope.
When the inclination angle of the spiral slope with respect to the direction perpendicular to the pile axis is θ 1 , and the inclination angle of the bearing surface with respect to the direction perpendicular to the pile axis is θ 2 , 5 ° ≦ θ 1 ≦ 45 °, 85 ° ≦ θ 2 ≦ 90 ° It is characterized by being set.

（４）また、上記（１）乃至（３）のいずれかに記載のものにおいて、前記第１外側継手管及び前記第２外側継手管と前記内側継手部材を締結するボルトを有し、前記第１外側継手管又は前記第２外側継手管に前記内側継手部材を前記ボルトで保持した状態で、前記内側継手部材は前記第１外側継手管又は前記第２外側継手管に対して内外方向に移動可能になっていることを特徴とするものである。 (4) Further, in any of the above (1) to (3), the first outer joint pipe and the second outer joint pipe and a bolt for fastening the inner joint member, The inner joint member moves inward and outward with respect to the first outer joint pipe or the second outer joint pipe in a state where the inner joint member is held by the bolt on the first outer joint pipe or the second outer joint pipe. It is characterized by being possible.

（５）また、上記（１）乃至（４）のいずれかに記載のものにおいて、前記内側継手部材の材料の引張強度を、回転杭を構成する鋼管、前記第１外側継手管及び前記第２外側継手管の材料の引張強度よりも大きくしたことを特徴とするものである。
(5) Moreover, in the thing in any one of said (1) thru | or (4), the tensile strength of the material of the said inner joint member is made into the steel pipe which comprises a rotary pile, the said 1st outer joint pipe, and the said 2nd. It is characterized by being larger than the tensile strength of the material of the outer joint pipe.

（６）また、上記（１）乃至（５）のいずれかに記載のものにおいて、前記第１外側継手管及び前記第２外側継手管の材料の引張強度を、回転杭を構成する鋼管と同じにしたことを特徴とするものである。 (6) Moreover, the thing in any one of said (1) thru | or (5) WHEREIN: The tensile strength of the material of the said 1st outer joint pipe and the said 2nd outer joint pipe is the same as the steel pipe which comprises a rotary pile. It is characterized by that.

本発明においては、上側の鋼管に作用する回転トルクを、第１外側継手管と第２外側継手管の接合端面によって、鋼材を最も有効に使える引張に構造的に変換し、発生した引張力を内側継手部材で受けることにより、回転杭工法の大きな回転トルクに対応でき、回転杭の正回転、逆回転を考慮した合理的な回転杭を構成する鋼管の接合構造を提供することができる。   In the present invention, the rotational torque acting on the upper steel pipe is structurally converted into a tension that can most effectively use the steel material by the joining end surfaces of the first outer joint pipe and the second outer joint pipe, and the generated tensile force is changed. By receiving it with the inner joint member, it is possible to provide a joint structure of steel pipes that can cope with a large rotational torque of the rotary pile construction method and constitute a rational rotary pile in consideration of normal rotation and reverse rotation of the rotary pile.

本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造全体を説明する説明図である。It is explanatory drawing explaining the whole joining structure of the steel pipe which comprises the rotary pile which concerns on one embodiment of this invention. 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の分解斜視図である。It is a disassembled perspective view of the joining structure of the steel pipe which comprises the rotary pile which concerns on one embodiment of this invention. 図１のＡ−Ａ矢視断面である。It is an AA arrow cross section of FIG. 図１のＢ−Ｂ矢視断面である。It is a BB arrow directional cross section of FIG. 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の第１外側継手管及び第２外側継手管の展開図である。It is an expanded view of the 1st outer joint pipe and 2nd outer joint pipe of the joining structure of the steel pipe which comprises the rotary pile which concerns on one embodiment of this invention. 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の内側継手部材について説明する説明図である。It is explanatory drawing explaining the inner side coupling member of the joining structure of the steel pipe which comprises the rotary pile which concerns on one embodiment of this invention. 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の第１外側継手管及び第２外側継手管と内側継手部材との締結構造について説明する説明図である。It is explanatory drawing explaining the fastening structure of the 1st outer joint pipe of the joining structure of the steel pipe which comprises the rotation pile which concerns on one embodiment of this invention, and the 2nd outer joint pipe, and an inner joint member. 回転杭の正回転時における本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の荷重の伝達メカニズムについて説明する説明図である。It is explanatory drawing explaining the transmission mechanism of the load of the joining structure of the steel pipe which comprises the rotary pile which concerns on one embodiment of this invention at the time of forward rotation of a rotary pile. 回転杭の逆回転時における本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の荷重の伝達メカニズムについて説明する説明図である。It is explanatory drawing explaining the transmission mechanism of the load of the joining structure of the steel pipe which comprises the rotary pile which concerns on one embodiment of this invention at the time of reverse rotation of a rotary pile. 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の接合方法について説明する説明図である。It is explanatory drawing explaining the joining method of the joining structure of the steel pipe which comprises the rotary pile which concerns on one embodiment of this invention. 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の接合方法の他の態様について説明する説明図である。It is explanatory drawing explaining the other aspect of the joining method of the joining structure of the steel pipe which comprises the rotary pile which concerns on one embodiment of this invention. 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の第１外側継手管及び第２外側継手管と内側継手部材との締結構造の他の態様について説明する説明図である。It is explanatory drawing explaining the other aspect of the fastening structure of the 1st outer joint pipe of the joining structure of the steel pipe which comprises the rotating pile which concerns on one embodiment of this invention, and a 2nd outer joint pipe, and an inner joint member. 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の第１外側継手管及び第２外側継手管と内側継手部材との締結構造のさらに他の態様について説明する説明図である。It is explanatory drawing explaining the further another aspect of the fastening structure of the 1st outer joint pipe of the joining structure of the steel pipe which comprises the rotation pile which concerns on one embodiment of this invention, and a 2nd outer joint pipe, and an inner joint member. . 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の第１外側継手管及び第２外側継手管の他の態様について説明する説明図である（その１）。It is explanatory drawing explaining the other aspect of the 1st outer joint pipe of the joining structure of the steel pipe which comprises the rotary pile which concerns on one embodiment of this invention, and a 2nd outer joint pipe (the 1). 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の第１外側継手管及び第２外側継手管の他の態様について説明する説明図である（その２）。It is explanatory drawing explaining the other aspect of the 1st outer joint pipe of the joining structure of the steel pipe which comprises the rotating pile which concerns on one embodiment of this invention, and a 2nd outer joint pipe (the 2). 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の第１外側継手管及び第２外側継手管の他の態様について説明する説明図である（その１）。It is explanatory drawing explaining the other aspect of the 1st outer joint pipe of the joining structure of the steel pipe which comprises the rotary pile which concerns on one embodiment of this invention, and a 2nd outer joint pipe (the 1). 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の第１外側継手管及び第２外側継手管の他の態様について説明する説明図である（その２）。It is explanatory drawing explaining the other aspect of the 1st outer joint pipe of the joining structure of the steel pipe which comprises the rotating pile which concerns on one embodiment of this invention, and a 2nd outer joint pipe (the 2). 本発明の一実施の形態に係る回転杭を構成する鋼管の接合構造の第１外側継手管及び第２外側継手管の他の態様について説明する説明図である（その３）。It is explanatory drawing explaining the other aspect of the 1st outer joint pipe of the joining structure of the steel pipe which comprises the rotating pile which concerns on one embodiment of this invention, and a 2nd outer joint pipe (the 3).

本発明の一実施の形態に係る回転杭１を構成する下鋼管３と上鋼管５の接合構造７（以下、単に「接合構造７」という）は、図１及び図２に示すように、下鋼管３の上端に取り付けられた第１外側継手管９と、上鋼管５の下端に取り付けられた第２外側継手管１１と、第１外側継手管９の上端面と第２外側継手管１１の下端面を当接させた状態で第１外側継手管９と第２外側継手管１１の内周面側においてこれらを連結する内側継手部材１３とを備えている。
以下に、各構成を詳細に説明する。 As shown in FIGS. 1 and 2, a joining structure 7 (hereinafter simply referred to as “joining structure 7”) of the lower steel pipe 3 and the upper steel pipe 5 constituting the rotary pile 1 according to the embodiment of the present invention is as follows. The first outer joint pipe 9 attached to the upper end of the steel pipe 3, the second outer joint pipe 11 attached to the lower end of the upper steel pipe 5, the upper end surface of the first outer joint pipe 9, and the second outer joint pipe 11 An inner joint member 13 is provided for connecting the first outer joint pipe 9 and the second outer joint pipe 11 on the inner peripheral surface side in a state where the lower end surfaces are in contact with each other.
Below, each structure is demonstrated in detail.

＜第１外側継手管９と第２外側継手管１１＞
第１外側継手管９と第２外側継手管１１は、図１に示すように、接合する下鋼管３と上鋼管５の端部にそれぞれ溶接によって取り付けられている。
第１外側継手管９と第２外側継手管１１の製造方法には、例えば鋼板を曲げ加工したリング又は鍛造・熱処理したリングを所定の形状に切削して製造する方法や、鋳造により製造する方法などがある。 <First outer joint pipe 9 and second outer joint pipe 11>
As shown in FIG. 1, the first outer joint pipe 9 and the second outer joint pipe 11 are attached to the ends of the lower steel pipe 3 and the upper steel pipe 5 to be joined by welding.
The manufacturing method of the first outer joint pipe 9 and the second outer joint pipe 11 includes, for example, a method in which a ring formed by bending a steel plate or a forged and heat-treated ring is cut into a predetermined shape and a method in which it is manufactured by casting. and so on.

第１外側継手管９の上端には接合端面１５が、第２外側継手管１１の下端には接合端面１７が設けられおり、第１外側継手管９と第２外側継手管１１は接合端面１５と接合端面１７を介して当接するようになっている。
接合端面１５は、図２に示すように、杭軸直角方向に対して傾斜する螺旋斜面１５ａと、螺旋斜面１５ａに連続し杭軸直角方向に対して傾斜する支圧面１５ｂとの組合せの複数からなり、接合端面１５全体として略のこ歯状を形成している。
接合端面１７も接合端面１５と同様に、杭軸直角方向に対して傾斜する螺旋斜面１７ａと、螺旋斜面１７ａに連続し杭軸直角方向に対して傾斜する支圧面１７ｂとの組合せの複数からなり、接合端面１７全体として略のこ歯状を形成している。 A joint end face 15 is provided at the upper end of the first outer joint pipe 9, and a joint end face 17 is provided at the lower end of the second outer joint pipe 11. The first outer joint pipe 9 and the second outer joint pipe 11 are joined end faces 15. And a contact end face 17.
As shown in FIG. 2, the joining end surface 15 includes a plurality of combinations of a spiral inclined surface 15 a that is inclined with respect to the direction perpendicular to the pile axis and a bearing surface 15 b that is continuous with the helical inclined surface 15 a and is inclined with respect to the direction perpendicular to the pile axis. Thus, the joint end face 15 as a whole has a substantially serrated shape.
Similarly to the joint end surface 15, the joint end surface 17 is composed of a plurality of combinations of a spiral slope 17 a that is inclined with respect to the direction perpendicular to the pile axis and a bearing surface 17 b that is continuous with the spiral slope 17 a and is inclined with respect to the direction perpendicular to the pile axis. As a whole, the joint end surface 17 has a substantially serrated shape.

螺旋斜面１５ａ及び螺旋斜面１７ａは、回転杭１の貫入時の回転方向に対して登り斜面となる方向に設定されており、回転杭１が正回転したときに第１外側継手管９と第２外側継手管１１が上下方向に離れるようになっている。なお、図１において正回転の方向を白抜き矢印で示す。   The spiral slope 15a and the spiral slope 17a are set in a direction that becomes an ascending slope with respect to the rotation direction when the rotary pile 1 penetrates, and when the rotary pile 1 rotates forward, the first outer joint pipe 9 and the second The outer joint pipe 11 is separated in the vertical direction. In FIG. 1, the direction of forward rotation is indicated by a white arrow.

図５に第１外側継手管９と第２外側継手管１１の展開図を示して接合端面１５及び接合端面１７の形状をより詳細に説明する。図５の展開図は、第１外側継手管９と第２外側継手管１１の全周の展開図であるので、展開図の横幅は第１外側継手管９（第２外側継手管１１）の周長に相当し、仮に第１外側継手管９（第２外側継手管１１）の直径をＤ(mm)とすれば、横幅はπ×Ｄ(mm)である。   FIG. 5 shows a developed view of the first outer joint pipe 9 and the second outer joint pipe 11, and the shapes of the joining end face 15 and the joining end face 17 will be described in more detail. The developed view of FIG. 5 is a developed view of the entire circumference of the first outer joint pipe 9 and the second outer joint pipe 11, and therefore the lateral width of the developed view is the first outer joint pipe 9 (second outer joint pipe 11). It corresponds to the circumference, and if the diameter of the first outer joint pipe 9 (second outer joint pipe 11) is D (mm), the lateral width is π × D (mm).

図５に示すように、螺旋斜面１５ａ（螺旋斜面１７ａ）と支圧面１５ｂ（支圧面１７ｂ）は全周に亘って４つずつ設けられている。図５において、螺旋斜面１５ａ（螺旋斜面１７ａ）は杭軸直角方向に対してθ1傾斜する直線で表されており、支圧面１５ｂ（支圧面１７ｂ）は同様に杭軸直角方向に対してθ2傾斜する直線で表されている。また、図５において、ボルトやボルト孔の図示は省略している。
図５に示すように、接合端面１５と接合端面１７とが全周に亘って当接（面接触）するようになっている。 As shown in FIG. 5, four spiral inclined surfaces 15a (spiral inclined surfaces 17a) and four bearing surfaces 15b (bearing surface 17b) are provided over the entire circumference. In FIG. 5, the spiral slope 15a (spiral slope 17a) is represented by a straight line inclined by θ 1 with respect to the direction perpendicular to the pile axis, and the bearing surface 15b (bearing surface 17b) is similarly θ with respect to the direction perpendicular to the pile axis. It is represented by two inclined straight lines. Moreover, in FIG. 5, illustration of a volt | bolt and a bolt hole is abbreviate | omitted.
As shown in FIG. 5, the joining end surface 15 and the joining end surface 17 are in contact (surface contact) over the entire circumference.

第１外側継手管９は内周面に内方向に突出する第１凸部２１を有し、また第２外側継手管１１は同じく内周面に内方に突出する第２凸部２３を有している。第１外側継手管９と第２外側継手管１１が接合端面１５と接合端面１７を介して当接すると、第１凸部２１と第２凸部２３が繋ぎ合わされて、円環状（図５の展開図においては帯状に表されている）の凸形を形成する。   The first outer joint pipe 9 has a first convex part 21 projecting inward on the inner peripheral surface, and the second outer joint pipe 11 has a second convex part 23 projecting inward on the inner peripheral surface. doing. When the first outer joint pipe 9 and the second outer joint pipe 11 come into contact with each other through the joint end face 15 and the joint end face 17, the first convex portion 21 and the second convex portion 23 are joined together to form an annular shape (see FIG. 5). A convex shape (shown in a band shape in the developed view) is formed.

第１外側継手管９と第２外側継手管１１の周面には、図１〜図４（主に図２及び図４参照）に示すように、内側継手部材１３をボルトで締結するための複数のボルト孔２７が周方向に所定間隔で設けられている。
ボルト孔２７の内周面にはねじ加工がされており、頭部にねじ加工されたボルト２５（図３参照、詳細は後述する）が挿入されて、その頭部と螺合可能になっている。なお、ボルト２５で内側継手部材１３を第１外側継手管９に締結した状態では、ボルト２５の頭部が第１外側継手管９表面から突出しないようになっている。
第２外側継手管１１には、外側から挿入されるボルトの頭部を格納するザグリ部２９を有するボルト孔３１が設けられており、ボルト締結後にボルトの頭部が継手表面から突出しないようになっている。 As shown in FIGS. 1 to 4 (mainly see FIGS. 2 and 4), the inner joint member 13 is fastened to the peripheral surfaces of the first outer joint pipe 9 and the second outer joint pipe 11 with bolts. A plurality of bolt holes 27 are provided at predetermined intervals in the circumferential direction.
The inner peripheral surface of the bolt hole 27 is threaded, and a bolt 25 (see FIG. 3; details will be described later) threaded into the head is inserted so that it can be screwed into the head. Yes. In the state where the inner joint member 13 is fastened to the first outer joint pipe 9 with the bolt 25, the head of the bolt 25 does not protrude from the surface of the first outer joint pipe 9.
The second outer joint pipe 11 is provided with a bolt hole 31 having a counterbore portion 29 for storing the head of a bolt inserted from the outside so that the head of the bolt does not protrude from the joint surface after the bolt is tightened. It has become.

＜内側継手部材＞
内側継手部材１３は、接合端面１５と接合端面１７を当接させた状態で第１外側継手管９と第２外側継手管１１をその内周面側において連結して、回転杭１が正回転したときに第１外側継手管９と第２外側継手管１１が離れようとするのに抵抗する部材である。
内側継手部材１３は、図２に示すように、第１外側継手管９の第１凸部２１と第２外側継手管１１の第２凸部２３に嵌合可能な凹部３３を有する複数の円弧状部材からなる。
内側継手部材１３は、例えば、鍛造・熱処理したリングの外周面を切削して凹部３３を形成し、その後、該リングにスリットを入れて複数の部材に分割することで製造される。 <Inner joint member>
The inner joint member 13 connects the first outer joint pipe 9 and the second outer joint pipe 11 on the inner peripheral surface side in a state where the joint end face 15 and the joint end face 17 are in contact with each other, and the rotary pile 1 rotates forward. This is a member that resists when the first outer joint pipe 9 and the second outer joint pipe 11 are about to separate.
As shown in FIG. 2, the inner joint member 13 has a plurality of circles each having a concave portion 33 that can be fitted to the first convex portion 21 of the first outer joint pipe 9 and the second convex portion 23 of the second outer joint pipe 11. It consists of an arc-shaped member.
The inner joint member 13 is manufactured, for example, by cutting the outer peripheral surface of a forged and heat-treated ring to form a recess 33, and then dividing the ring into a plurality of members by slitting the ring.

複数の内側継手部材１３を第１外側継手管９及び第２外側継手管１１の内周面に配置した状態の一例を図６に示す。なお、内側継手部材１３の配置が分かり易いように、図６において第１外側継手管９と第２外側継手管１１を破線で示す。この例では４つの内側継手部材１３が第１外側継手管９と第２外側継手管１１の全内周に亘って配置されている（図６（ｂ）参照）。
上述したとおり、第１外側継手管９と第２外側継手管１１が当接状態において、第１凸部２１と第２凸部２３が繋ぎ合わされて円環状に凸形状になり、この円環凸形状に内側継手部材１３の凹部３３が嵌合している（図６（ａ）参照）。 An example of the state which has arrange | positioned the some inner joint member 13 to the internal peripheral surface of the 1st outer joint pipe 9 and the 2nd outer joint pipe 11 is shown in FIG. In addition, the 1st outer joint pipe 9 and the 2nd outer joint pipe 11 are shown with a broken line in FIG. 6 so that arrangement | positioning of the inner joint member 13 can be understood easily. In this example, four inner joint members 13 are arranged over the entire inner circumference of the first outer joint pipe 9 and the second outer joint pipe 11 (see FIG. 6B).
As described above, when the first outer joint pipe 9 and the second outer joint pipe 11 are in contact with each other, the first convex portion 21 and the second convex portion 23 are joined to form an annular convex shape. The recess 33 of the inner joint member 13 is fitted into the shape (see FIG. 6A).

内側継手部材１３には、図７に示すように、ボルト孔が上下２段に複数設けられており、下段に設けられたものが第１外側継手管９のボルト孔２７に対応するボルト孔３５であり、上段に設けられたものが第２外側継手管１１のボルト孔３１に対応するボルト孔３７である。
ボルト孔３５の内周面にねじ加工はなされておらず、ボルト２５とナット３９を用いて締結する。内側継手部材１３の内側の面には、ナット３９が収納されるザグリ孔４１が設けられている。
他方、ボルト孔３７の内周面はねじ加工がなされている。
なお、周方向のボルトの配置は、１つの内側継手部材１３につき2〜5箇所とすることが望ましい。例えば、４つの内側継手部材１３を用いる場合、各内側継手部材１３の両端の上下をボルトで締結するようにすればよい。この場合、ボルト本数は全部で16本（4×2箇所×2段）となる。 As shown in FIG. 7, the inner joint member 13 is provided with a plurality of bolt holes in two upper and lower stages, and the one provided in the lower stage is a bolt hole 35 corresponding to the bolt hole 27 of the first outer joint pipe 9. What is provided in the upper stage is a bolt hole 37 corresponding to the bolt hole 31 of the second outer joint pipe 11.
The inner peripheral surface of the bolt hole 35 is not threaded and is fastened using the bolt 25 and the nut 39. A counterbore hole 41 in which a nut 39 is accommodated is provided on the inner surface of the inner joint member 13.
On the other hand, the inner peripheral surface of the bolt hole 37 is threaded.
In addition, as for the arrangement | positioning of the volt | bolt of the circumferential direction, it is desirable to set it as 2-5 places per one inner side coupling member 13. FIG. For example, when four inner joint members 13 are used, the upper and lower ends of each inner joint member 13 may be fastened with bolts. In this case, the total number of bolts is 16 (4 × 2 locations × 2 stages).

＜ボルト＞
図７に示すように、第１外側継手管９と内側継手部材１３とを締結するには上述したようにボルト２５及びナット３９を用い、第２外側継手管１１と内側継手部材１３とを締結するには、六角穴４３ａ付きのボルト４３を用いる。ボルト２５の頭部にはボルト２５を回転させるための六角穴２５ａが設けられている。 <Bolt>
As shown in FIG. 7, in order to fasten the first outer joint pipe 9 and the inner joint member 13, the bolt 25 and the nut 39 are used to fasten the second outer joint pipe 11 and the inner joint member 13 as described above. For this purpose, a bolt 43 with a hexagonal hole 43a is used. The head of the bolt 25 is provided with a hexagon hole 25a for rotating the bolt 25.

次に、以上のように構成された接合構造７における荷重（圧縮力、引張力、曲げモーメント、せん断力、正回転トルク）の伝達メカニズムについて概説する。
接合構造７に作用する圧縮力は、第１外側継手管９の接合端面１５及び第２外側継手管１１の接合端面１７で伝達される。
引張力は、内側継手部材１３の水平断面、第１外側継手管９の第１凸部２１と第２外側継手管１１の第２凸部２３及び内側継手部材１３の凹部３３の支圧面及びせん断面で伝達される。
曲げモーメントは、上記の圧縮力と引張力の組合せで伝達される。
せん断力は、内側継手部材１３の水平断面で伝達される。
正回転トルクは引張力の場合と同様である。 Next, the transmission mechanism of the load (compression force, tensile force, bending moment, shearing force, positive rotational torque) in the joining structure 7 configured as described above will be outlined.
The compressive force acting on the joint structure 7 is transmitted on the joint end face 15 of the first outer joint pipe 9 and the joint end face 17 of the second outer joint pipe 11.
The tensile force is determined by the horizontal cross section of the inner joint member 13, the bearing surface of the first convex portion 21 of the first outer joint pipe 9, the second convex portion 23 of the second outer joint pipe 11, and the concave portion 33 of the inner joint member 13. Transmitted in cross section.
The bending moment is transmitted by a combination of the compression force and the tensile force.
The shearing force is transmitted at the horizontal cross section of the inner joint member 13.
The positive rotational torque is the same as in the case of tensile force.

回転杭１の地盤中への回転貫入は、上鋼管５に正回転トルクを与え、該回転トルクによる水平力が下鋼管３に伝達されて、回転杭１全体が回転することで行われる。
回転杭１の回転貫入時における、上鋼管５から下鋼管３への荷重の伝達メカニズムについて図８に基づいて説明する。
図８（ａ）は、第１外側継手管９の接合端面１５と第２外側継手管１１の接合端面１５、１７が当接している状態を示しており、図８（ｂ）は図８（ａ）における接合端面１５及び接合端面１７の展開図の一部を示したものである。
図８（ｂ）において、力を白抜き矢印（力ａ、力ｂ、力ｃ、力ｄ、力ｅ、力ｆ、力ｇ）で示す。また、図８（ｂ）において、矢印で示す各力が、第１外側継手管９と第２外側継手管１１のいずれかに作用しているかを分かり易くするために、第１外側継手管９と第２外側継手管１１同士を上下に離して図示している。 The rotation penetration of the rotary pile 1 into the ground is performed by applying a positive rotational torque to the upper steel pipe 5 and transmitting the horizontal force due to the rotational torque to the lower steel pipe 3 so that the entire rotary pile 1 rotates.
A mechanism for transmitting a load from the upper steel pipe 5 to the lower steel pipe 3 at the time of the rotary penetration of the rotary pile 1 will be described with reference to FIG.
FIG. 8A shows a state where the joining end face 15 of the first outer joint pipe 9 and the joining end faces 15 and 17 of the second outer joint pipe 11 are in contact with each other, and FIG. A part of the expanded view of the joining end surface 15 and the joining end surface 17 in a) is shown.
In FIG. 8B, the force is indicated by white arrows (force a, force b, force c, force d, force e, force f, force g). Further, in FIG. 8B, in order to make it easy to understand whether each force indicated by an arrow acts on either the first outer joint pipe 9 or the second outer joint pipe 11, the first outer joint pipe 9. And the second outer joint pipe 11 are shown apart from each other in the vertical direction.

図８（ａ）の状態において、上鋼管５に回転トルクを作用させると、回転トルクによる力ａは、上鋼管５に作用する螺旋斜面１７ａに沿う力ｂと、下鋼管３に作用する螺旋斜面１５ａに直交する力ｃに分力することができる。
そして、力ｂは回転方向の力ｄと上向きの力ｅに分力でき、また、力ｃも回転方向の力ｆと下向きの力ｇに分力できる。
このように、回転トルクによる力ａの一部が杭軸方向の力（力ｅ、力ｇ）に変換され、これらの力は、接合端面１５、１７を上下に引き離そうとする力であるが、これらの力が第１外側継手管９の第１凸部２１と第２外側継手管１１の第２凸部２３にせん断力及び支圧力として作用し、この力が内側継手部材１３の凹部３３にせん断力として作用し、最終的にはこの力が内側継手部材１３に引張力として作用する。
引張強度はせん断強度よりも高いため、内側継手部材１３に引張力として作用させることで接合構造全体としてのねじり耐力を効率的に向上させることができる。 When a rotational torque is applied to the upper steel pipe 5 in the state of FIG. 8A, the force a due to the rotational torque is a force b along the helical slope 17 a acting on the upper steel pipe 5 and a helical slope acting on the lower steel pipe 3. The force c can be divided into a force c orthogonal to 15a.
The force b can be divided into a rotational force d and an upward force e, and the force c can be divided into a rotational force f and a downward force g.
Thus, a part of the force a due to the rotational torque is converted into a force (force e, force g) in the pile axis direction, and these forces are forces that try to separate the joining end faces 15 and 17 up and down. These forces act on the first convex portion 21 of the first outer joint pipe 9 and the second convex portion 23 of the second outer joint pipe 11 as shear force and supporting pressure, and this force acts on the concave portion 33 of the inner joint member 13. This acts as a shearing force, and finally this force acts on the inner joint member 13 as a tensile force.
Since the tensile strength is higher than the shear strength, the torsional strength of the entire joint structure can be efficiently improved by causing the inner joint member 13 to act as a tensile force.

このように内側継手部材１３は、接合構造全体のねじり耐力を向上させるための重要な役割を担っている。そのため、内側継手部材１３の材料強度は、下鋼管３、上鋼管５、第１外側継手管９及び第２外側継手管１１の材料強度よりも大きくすることが望ましい。逆に、第１外側継手管９及び第２外側継手管１１の材料強度は、下鋼管３、上鋼管５と同じにすることができる。   Thus, the inner joint member 13 plays an important role for improving the torsional strength of the entire joint structure. Therefore, it is desirable that the material strength of the inner joint member 13 is greater than the material strength of the lower steel pipe 3, the upper steel pipe 5, the first outer joint pipe 9, and the second outer joint pipe 11. Conversely, the material strength of the first outer joint pipe 9 and the second outer joint pipe 11 can be the same as that of the lower steel pipe 3 and the upper steel pipe 5.

このように、回転トルクを支圧力やせん断力ではなく鋼材を最も有効に使える引張力に構造的に変換することにより、継手寸法を小さく抑えつつ、下鋼管３及び上鋼管５に作用するトルク以上のねじり耐力を有する接合構造７とすることが可能である。   As described above, the rotational torque is structurally converted to the tensile force that can use the steel material most effectively instead of the supporting pressure and the shearing force, thereby suppressing the joint size to be small and more than the torque acting on the lower steel pipe 3 and the upper steel pipe 5. It is possible to obtain a joint structure 7 having a torsional strength of 1 mm.

なお、力ｄ及び力ｆは第２外側継手管１１、ひいては下鋼管３を回転させるトルクとして伝達され、回転杭１全体が回転貫入される。
また、杭施工時には逆回転をする場合もあり、そのときの回転トルクによる水平力ｈは、図９に示すように、支圧面１５ｂ及び支圧面１７ｂに支圧及びせん断力として伝達される。逆回転時の回転トルクは、正回転時に比べれば小さいのでせん断力として伝達しても問題なく、また第１外側継手管９及び第２外側継手管１１の全周長（せん断面４５）を考慮することができるのでこの点でも問題ない。 The force d and the force f are transmitted as torque for rotating the second outer joint pipe 11, and consequently the lower steel pipe 3, and the entire rotary pile 1 is rotated and penetrated.
Further, there is a case of reverse rotation at the time of pile construction, and the horizontal force h due to the rotational torque at that time is transmitted as a bearing pressure and a shearing force to the bearing surface 15b and the bearing surface 17b as shown in FIG. Since the rotational torque at the time of reverse rotation is smaller than that at the time of forward rotation, there is no problem even if it is transmitted as a shearing force, and the entire circumferential length (shear surface 45) of the first outer joint pipe 9 and the second outer joint pipe 11 is considered There is no problem in this point as well.

本実施の形態の接合構造７は、回転トルクの一部を構造的に引張力に変換することができる。このときの変換率は、螺旋斜面１５ａ及び螺旋斜面１７ａの傾斜角度θ1を変更することで調整することができる。
傾斜角度θ1は5°≦θ1≦45°に設定し、傾斜角度θ2は85°≦θ2≦90°に設定することが望ましい。この理由について以下に説明する。 The joint structure 7 of the present embodiment can structurally convert a part of the rotational torque into a tensile force. The conversion rate at this time can be adjusted by changing the inclination angle θ 1 of the spiral slope 15a and the spiral slope 17a.
The inclination angle θ 1 is desirably set to 5 ° ≦ θ 1 ≦ 45 °, and the inclination angle θ 2 is desirably set to 85 ° ≦ θ 2 ≦ 90 °. The reason for this will be described below.

傾斜角度θ1は、正回転時に滑り上がろうとする力を積極的に発生させるために45°以下とした。ただし、傾斜角度θ1が小さすぎると、内側継手部材１３に引張力が伝達されずに第１外側継手管９及び第２外側継手管１１がほぼ水平にねじられ、ボルトのみに大きなせん断力が作用してしまう。これを回避するために、ボルトに大きなせん断力が作用せず、かつ内側継手部材１３に引張力が伝達される最小角度5°を、傾斜角度θ1の下限値とした。 The inclination angle θ 1 is set to 45 ° or less in order to positively generate a force to slide up during forward rotation. However, if the inclination angle θ 1 is too small, the first outer joint pipe 9 and the second outer joint pipe 11 are twisted almost horizontally without transmitting a tensile force to the inner joint member 13, and a large shear force is applied only to the bolt. Will work. In order to avoid this, the minimum angle 5 ° at which a large shearing force does not act on the bolt and the tensile force is transmitted to the inner joint member 13 is set as the lower limit value of the inclination angle θ 1 .

一方、支圧面１５ｂ及び支圧面１７ｂの傾斜角度θ2は、逆回転時の比較的小さな回転トルクを伝達できればよいため、角度を85°以上90°以下として、支圧面１５ｂ及び支圧面１７ｂの支圧及びせん断により、回転トルクを伝達するようにした。 On the other hand, the inclination angle θ 2 of the bearing surface 15b and the bearing surface 17b only needs to be able to transmit a relatively small rotational torque at the time of reverse rotation, so that the angle is set to 85 ° to 90 ° and the bearing surface 15b and the bearing surface 17b are supported. Rotational torque was transmitted by pressure and shear.

次に、本実施の形態に係る接合構造７の標準的な接合手順として下記(1)〜(8)ついて、図１０を参照しながら詳細に説明する。図１０は、接合構造７の縦断面の左半分を図示したものである。   Next, the following (1) to (8) as a standard joining procedure of the joining structure 7 according to the present embodiment will be described in detail with reference to FIG. FIG. 10 illustrates the left half of the longitudinal section of the joint structure 7.

(1)下鋼管３の上端部（杭頭部）に第１外側継手管９を、上鋼管５の下端部に第２外側継手管１１をそれぞれ工場溶接して取り付けておく。
(2)下鋼管３を地盤中に打設する（図１０（ａ）参照）。
(3)ボルト２５を、第１外側継手管９のボルト孔２７に挿入し、さらに内側継手部材１３のボルト孔３５に挿入し、ナット３９を締め付けることで第１外側継手管９に内側継手部材１３を締結する（図１０（ｂ）参照）。 (1) The first outer joint pipe 9 is attached to the upper end (pile head) of the lower steel pipe 3 and the second outer joint pipe 11 is attached to the lower end of the upper steel pipe 5 by factory welding.
(2) The lower steel pipe 3 is driven into the ground (see FIG. 10 (a)).
(3) The bolt 25 is inserted into the bolt hole 27 of the first outer joint pipe 9, further inserted into the bolt hole 35 of the inner joint member 13, and the nut 39 is tightened to tighten the nut 39 to the inner joint member. 13 is fastened (see FIG. 10B).

(4)ボルト２５を回転して、ボルト２５の頭部を内側にねじ込み、内側継手部材１３を内方向に移動させる（図１０（ｃ）参照）。このとき、ナット３９は、ザグリ孔４１の中でボルト２５の回転に伴って回転して、ボルト２５とナット３９と内側継手部材１３間の相対距離が変わらない。内側継手部材１３を内方向に移動させることで、上鋼管５を建て込んで第２外側継手管１１を接合する際に、内側継手部材１３が第２外側継手管１１と緩衝せずに接合の妨げになることがない。 (4) The bolt 25 is rotated, the head of the bolt 25 is screwed inward, and the inner joint member 13 is moved inward (see FIG. 10C). At this time, the nut 39 rotates in the counterbore hole 41 as the bolt 25 rotates, and the relative distance between the bolt 25, the nut 39, and the inner joint member 13 does not change. By moving the inner joint member 13 inward, when the upper steel pipe 5 is built and the second outer joint pipe 11 is joined, the inner joint member 13 is joined to the second outer joint pipe 11 without being buffered. There is no hindrance.

(5)上鋼管５を建て込み、第２外側継手管１１を内側継手部材１３の外側に挿入し、接合端面１５と接合端面１７とを当接させる（図１０（ｄ）参照）。
(6)ボルト２５を逆回転させて、内側継手部材１３を外方向に移動させる。これにより、内側継手部材１３の凹部３３が、第１外側継手管９の第１凸部２１及び第２外側継手管１１の第２凸部２３に嵌合する（図１０（ｅ）参照）。
(7)第２外側継手管１１のボルト孔３１にボルト４３を挿入し、内側継手部材１３のボルト孔３７に螺入することで第２外側継手管１１と内側継手部材１３をボルト固定する（図１０（ｆ）参照）。
(8)最後に、下鋼管３及び上鋼管５のすべてのボルト頭部が継手表面から突出していないことを確認して、接合完了となる。 (5) The upper steel pipe 5 is installed, the second outer joint pipe 11 is inserted outside the inner joint member 13, and the joining end face 15 and the joining end face 17 are brought into contact with each other (see FIG. 10 (d)).
(6) The bolt 25 is reversely rotated to move the inner joint member 13 outward. Thereby, the recessed part 33 of the inner joint member 13 fits into the 1st convex part 21 of the 1st outer joint pipe 9, and the 2nd convex part 23 of the 2nd outer joint pipe 11 (refer FIG.10 (e)).
(7) The bolts 43 are inserted into the bolt holes 31 of the second outer joint pipe 11 and screwed into the bolt holes 37 of the inner joint member 13 to fix the second outer joint pipe 11 and the inner joint member 13 with bolts ( (Refer FIG.10 (f)).
(8) Finally, it is confirmed that all bolt heads of the lower steel pipe 3 and the upper steel pipe 5 do not protrude from the joint surface, and the joining is completed.

なお、下鋼管３の打設時に上端部（杭頭部）を養生可能ならば、上記(3)の内側継手部材１３の取付け工程を上記(2)の前に行っておき、上記(2)の下鋼管３の打設完了後に上記(4)から作業するようにしてもよい。これにより、接合時間のさらなる短縮を図ることが可能となる。   If the upper end (pile head) can be cured at the time of placing the lower steel pipe 3, the mounting process of the inner joint member 13 of the above (3) is performed before the above (2) and the above (2) You may make it work from said (4) after completion of placement of lower steel pipe 3. This makes it possible to further shorten the joining time.

また、上鋼管５の建て込み時に下端部を養生可能ならば、図１１に示すように、ボルトやボルト孔等の配置と形状を図１０に示すものの場合と全く逆にして、内側継手部材１３を第２外側継手管１１に取り付け、上鋼管５の建て込み後に下鋼管３の第１外側継手管９と内側継手部材１３をボルト締結するようにしてもよい。   Further, if the lower end portion can be cured when the upper steel pipe 5 is built, as shown in FIG. 11, the arrangement and shape of bolts, bolt holes, etc. are completely reversed from those shown in FIG. May be attached to the second outer joint pipe 11 and the first outer joint pipe 9 and the inner joint member 13 of the lower steel pipe 3 may be bolted after the upper steel pipe 5 is installed.

下鋼管３側のボルト２５の頭部をねじ加工にしているのは、上鋼管５を建て込む際に、内側継手部材１３を内方向に移動させて上鋼管５を建て込み、再び外方向に移動させるまでの間（上記(4)〜(6)参照）、内側継手部材１３を垂直に保持するためである。
したがって、接合する下鋼管３及び上鋼管５が小径で内側継手部材１３が小さい場合など、内側継手部材１３の保持に支障がなければ、図１２（ｂ）に示すように、ボルトを下鋼管３及び上鋼管５側とも軸部のみがねじ加工が施された通常の六角穴４７ａ付きのボルト４７とし、ボルト孔等もそれに対応するもの（ザグリ孔４９、ボルト孔５０、ボルト孔５１）でもよい。この場合、ボルト４７の回転量を調整することで、図１２（ａ）に示すように、内側継手部材１３を内方向へ移動可能である。 The head of the bolt 25 on the side of the lower steel pipe 3 is threaded. When the upper steel pipe 5 is installed, the inner joint member 13 is moved inward to install the upper steel pipe 5 and again outward. This is because the inner joint member 13 is held vertically until it is moved (see (4) to (6) above).
Therefore, when the lower steel pipe 3 and the upper steel pipe 5 to be joined have a small diameter and the inner joint member 13 is small, if the holding of the inner joint member 13 is not hindered, as shown in FIG. In addition, the bolt 47 with a normal hexagonal hole 47a in which only the shaft portion is threaded on the upper steel pipe 5 side may be used, and the bolt hole or the like (bore hole 49, bolt hole 50, bolt hole 51) may be used. . In this case, by adjusting the rotation amount of the bolt 47, the inner joint member 13 can be moved inward as shown in FIG.

また、ボルト４７の頭部が継手表面から突出していても施工上、杭の周面摩擦力への影響がない場合では、図１３に示すように、ザグリ孔を設けなくともよい。   Further, when the head portion of the bolt 47 protrudes from the joint surface, there is no need to provide a counterbore hole as shown in FIG.

以上のように、本実施の形態においては、回転トルクを支圧やせん断ではなく鋼材を最も有効に使える引張に構造的に変換し、発生した引張力を内側継手部材１３で受けることにより、継手寸法を抑えつつ、下鋼管３及び上鋼管５の全強トルク以上の大きな回転トルクに対応でき、回転杭１の正回転、逆回転を考慮した合理的な接合構造７とすることができる。
また、ボルトの頭部が継手表面から突出しないようになっているので、回転貫入時の抵抗をなくすことができ、回転杭１の周面摩擦力への影響を低減できる。 As described above, in the present embodiment, the rotational torque is structurally converted to tension that can use the steel material most effectively instead of bearing pressure or shear, and the generated tensile force is received by the inner joint member 13, thereby While suppressing the dimensions, it is possible to cope with a large rotational torque that is greater than or equal to the total strong torque of the lower steel pipe 3 and the upper steel pipe 5, and it is possible to provide a rational joint structure 7 in consideration of normal rotation and reverse rotation of the rotary pile 1.
Moreover, since the head part of the bolt does not protrude from the joint surface, the resistance at the time of rotation penetration can be eliminated, and the influence on the circumferential frictional force of the rotary pile 1 can be reduced.

なお、上記では、傾斜角度θ2が90°である例について説明したが、図１４に示すように傾斜角度θ2を小さく設定して支圧面１５ｂ及び支圧面１７ｂの傾きを比較的緩やかにしてもよい。より好ましくは、上述したとおり85°≦θ2≦90°に設定する。
また、凸凹部１１は、図５に示す形状の他、嵌合性を向上させるために、図１５に示すように螺旋斜面１５ａと支圧面１５ｂの交差部、及び螺旋斜面１７ａと支圧面１７ｂの交差部にアールを形成するようにしてもかまわない。 In the above description, the example in which the inclination angle θ 2 is 90 ° has been described. However, as shown in FIG. 14, the inclination angle θ 2 is set small, and the inclinations of the bearing surface 15b and the bearing surface 17b are made relatively gentle. Also good. More preferably, it is set to 85 ° ≦ θ 2 ≦ 90 ° as described above.
In addition to the shape shown in FIG. 5, the convex recess 11 has an intersection between the spiral inclined surface 15 a and the bearing surface 15 b, and between the spiral inclined surface 17 a and the bearing surface 17 b as shown in FIG. 15. You may make it form a round at the intersection.

さらに、第１外側継手管９と第２外側継手管１１の位置決めや芯合わせが容易となるように、図１６に示すように第２外側継手管１１の支圧面１７ｂに溝部５３を設け、第１外側継手管９の支圧面１５ｂに、溝部５３が挿入される凸条部５５を設けてもよい。第１外側継手管９の上面視を図１７に示す。なお、溝部５３の形状は図１８（ａ）〜（ｃ）に示すようなものでもよい。   Further, as shown in FIG. 16, a groove portion 53 is provided on the bearing surface 17b of the second outer joint pipe 11 so that the first outer joint pipe 9 and the second outer joint pipe 11 can be easily positioned and aligned. A convex strip 55 into which the groove 53 is inserted may be provided on the bearing surface 15 b of the outer joint pipe 9. A top view of the first outer joint pipe 9 is shown in FIG. In addition, the shape of the groove part 53 may be as shown in FIGS.

本発明の鋼管杭の接合構造の一設計例を示す。
外径φ609.6mm×板厚t12mmの鋼管杭（SKK400）に対して本発明の接合構造を設計した場合、例えば以下のようになる。
・第１外側継手管及び第２外側継手管：外径φ609.6mm×板厚t12mm（凸型増厚部はt25mm）×長さL70mm（同L35mm）、凸凹部は4つ、傾斜角度θ1は5°、傾斜角度θ2は90°、材質はSM400A
・内側継手部材：外径φ585.6（凹型円弧部はφ559.6mm）×板厚t23mm（同t10mm）×長さL110mm（同L70mm）、4分割、材質はHITEN780
・六角穴付きボルト：M12、本数は24本（4分割×3箇所×2段） The design example of the joining structure of the steel pipe pile of this invention is shown.
When the joint structure of the present invention is designed for a steel pipe pile (SKK400) having an outer diameter φ609.6 mm × plate thickness t12 mm, for example, the following is obtained.
-1st outer joint pipe and 2nd outer joint pipe: Outer diameter φ609.6mm x Plate thickness t12mm (convex thickened part is t25mm) x length L70mm (same L35mm), four convex concave parts, inclination angle θ 1 Is 5 °, inclination angle θ 2 is 90 °, material is SM400A
・ Inner joint member: Outer diameter φ585.6 (concave arc part is φ559.6mm) x plate thickness t23mm (same t10mm) x length L110mm (same L70mm), divided into 4 parts, material is HITEN780
-Hexagon socket head cap bolt: M12, 24 bolts (4 divisions x 3 locations x 2 stages)

ａ、ｂ、ｃ、ｄ、ｅ、ｆ、ｇ、ｈ 力
１ 回転杭
３ 下鋼管
５ 上鋼管
７ 接合構造
９ 第１外側継手管
１１ 第２外側継手管
１３ 内側継手部材
１５ 接合端面
１５ａ 螺旋斜面
１５ｂ 支圧面
１７ 接合端面
１７ａ 螺旋斜面
１７ｂ 支圧面
１９ 支圧面
２１ 第１凸部
２３ 第２凸部
２５ ボルト
２５ａ 六角穴
２７ ボルト孔
２９ ザグリ部
３１ ボルト孔
３３ 凹部
３５ ボルト孔
３７ ボルト孔
３９ ナット
４１ ザグリ孔
４３ ボルト
４３ａ 六角穴
４５ せん断面
４７ ボルト
４７ａ 六角穴
４９ ザグリ孔
５０ ボルト孔
５１ ボルト孔
５３ 溝部
５５ 凸条部 a, b, c, d, e, f, g, h force 1 rotating pile 3 lower steel pipe 5 upper steel pipe 7 joint structure 9 first outer joint pipe 11 second outer joint pipe 13 inner joint member 15 joint end face 15a spiral slope 15b bearing surface 17 joint end surface 17a spiral slope 17b bearing surface 19 bearing surface 21 first convex portion 23 second convex portion 25 bolt 25a hexagonal hole 27 bolt hole 29 counterbore portion 31 bolt hole 33 concave portion 35 bolt hole 37 bolt hole 39 nut 41 Counterbored hole 43 Bolt 43a Hexagonal hole 45 Shear surface 47 Bolt 47a Hexagonal hole 49 Counterbored hole 50 Bolt hole 51 Bolt hole 53 Groove 55 Projection

Claims (3)

回転杭を構成する上下の鋼管を接合する接合構造であって、
下側の鋼管の上端に取り付けられた第１外側継手管と、上側の鋼管の下端に取り付けられた第２外側継手管と、前記第１外側継手管の上端面と前記第２外側継手管の下端面を当接させた状態で前記第１外側継手管と前記第２外側継手管の内周面側においてこれらを連結する内側継手部材とを備え、
前記第１外側継手管と前記第２外側継手管は、前記回転杭が正回転したときに両者が上下方向に離れる方向となる複数の螺旋斜面を有する接合端面を介して当接し、前記内側継手部材は前記第１外側継手管と前記第２外側継手管が離れようとするのに抵抗するようになっており、
前記第１外側継手管及び前記第２外側継手管の接合端面は、前記螺旋斜面に連続する支圧面を有し、
前記螺旋斜面の杭軸直角方向に対する傾斜角度をθ 1 、前記支圧面の杭軸直角方向に対する傾斜角度をθ 2 とすると、5°≦θ 1 ≦45°、85°≦θ 2 ≦90°に設定されていることを特徴とする回転杭を構成する鋼管の接合構造。 A joining structure for joining the upper and lower steel pipes constituting the rotating pile,
A first outer joint pipe attached to the upper end of the lower steel pipe, a second outer joint pipe attached to the lower end of the upper steel pipe, an upper end surface of the first outer joint pipe, and the second outer joint pipe An inner joint member for connecting the first outer joint pipe and the second outer joint pipe on the inner peripheral surface side in a state where the lower end surface is in contact with each other;
The first outer joint pipe and the second outer joint pipe are in contact with each other through joint end surfaces having a plurality of spiral slopes that are separated in the vertical direction when the rotary pile rotates forward, and the inner joint The member is adapted to resist the separation of the first outer joint pipe and the second outer joint pipe .
The joining end faces of the first outer joint pipe and the second outer joint pipe have a bearing surface that is continuous with the spiral slope,
When the inclination angle of the spiral slope with respect to the direction perpendicular to the pile axis is θ 1 , and the inclination angle of the bearing surface with respect to the direction perpendicular to the pile axis is θ 2 , 5 ° ≦ θ 1 ≦ 45 °, 85 ° ≦ θ 2 ≦ 90 ° A steel pipe joint structure constituting a rotating pile characterized by being set . 前記第１外側継手管は内周面に内方向に突出する第１凸部を有し、前記第２外側継手管は内周面に内方に突出する第２凸部を有し、前記内側継手部材は前記第１凸部と前記第２凸部に嵌合可能な凹部を有する複数の円弧状部材からなることを特徴とする請求項１記載の回転杭を構成する鋼管の接合構造。   The first outer joint pipe has a first convex part projecting inward on the inner peripheral surface, and the second outer joint pipe has a second convex part projecting inward on the inner peripheral surface, The joint structure of a steel pipe constituting a rotating pile according to claim 1, wherein the joint member is composed of a plurality of arc-shaped members having recesses that can be fitted to the first protrusions and the second protrusions. 前記第１外側継手管及び前記第２外側継手管と前記内側継手部材を締結するボルトを有し、前記第１外側継手管又は前記第２外側継手管に前記内側継手部材を前記ボルトで保持した状態で、前記内側継手部材は前記第１外側継手管又は前記第２外側継手管に対して内外方向に移動可能になっていることを特徴とする請求項１又は２に記載の回転杭を構成する鋼管の接合構造。 A bolt for fastening the first outer joint pipe and the second outer joint pipe and the inner joint member is provided, and the inner joint member is held by the bolt on the first outer joint pipe or the second outer joint pipe. The rotary pile according to claim 1 or 2 , wherein the inner joint member is movable inward and outward with respect to the first outer joint pipe or the second outer joint pipe. Steel pipe joining structure.
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