JP7051567B2

JP7051567B2 - Excavation agitation head

Info

Publication number: JP7051567B2
Application number: JP2018089252A
Authority: JP
Inventors: 節堀切; 雅博石川; 篤史村山; 耕寛山路; 裕貴日下; 篤史加藤
Original assignee: Nippon Steel Corp; Tenox Corp
Current assignee: Nippon Steel Corp; Tenox Corp
Priority date: 2018-05-07
Filing date: 2018-05-07
Publication date: 2022-04-11
Anticipated expiration: 2038-05-07
Also published as: JP2019196591A

Description

本発明は、ソイルセメント柱と鋼管とからなる鋼管ソイルセメント杭を築造する際に用いられる鋼管ソイルセメント杭施工用の掘削撹拌ヘッドに関し、特に硬質地盤に到達後も硬質地盤による掘進抵抗を低減して鋼管ソイルセメント杭の継続施工を可能にすると共に、施工終了後は地表まで速やかに引き上げられるようにしたものである。 The present invention relates to an excavation stirring head for constructing a steel pipe soil cement pile used when constructing a steel pipe soil cement pile composed of a soil cement column and a steel pipe, and particularly reduces the excavation resistance due to the hard ground even after reaching the hard ground. The steel pipe soil cement pile can be continuously constructed and can be quickly pulled up to the ground surface after the construction is completed.

鋼管ソイルセメント杭は、地盤内に掘削土と固化材(例えば、セメントミルク)とからなるソイルセメント柱を築造し、その中に外面突起付き鋼管などの鋼管を沈設することにより築造される。また、ソイルセメント柱は、例えば、特許文献１に開示されているような、掘削軸(1)に掘削翼(2)、撹拌翼(3)および共回り防止翼(4)を備えた混合撹拌装置を用い、掘削翼(2)によって地盤を掘削しながら掘削軸(1)の先端から固化材を吐出し、撹拌翼(2)と共回り防止翼(4)とによって掘削土と固化材とを混合撹拌することにより築造される。 Steel pipe soil cement piles are constructed by constructing soil cement columns made of excavated soil and solidifying material (for example, cement milk) in the ground, and laying steel pipes such as steel pipes with external protrusions in them. Further, the soil cement column is, for example, as disclosed in Patent Document 1, in which the excavation shaft (1) is provided with an excavation blade (2), a stirring blade (3) and a co-rotation prevention blade (4) for mixed stirring. Using the device, while excavating the ground with the excavation blade (2), the solidifying material is discharged from the tip of the excavation shaft (1), and the excavated soil and solidifying material are discharged by the stirring blade (2) and the co-rotation prevention blade (4). Is built by mixing and stirring.

特に、共回り防止翼(4)は、掘削翼(2)と撹拌翼(3)との間に回転フリーな状態で設置され、かつ掘削翼(2)および撹拌翼(3)より長く、先端が周囲地盤内に食い込むことで、掘削翼(2)および撹拌翼(3)が掘削軸(1)と共に地盤内を回転掘進しても回転することなく、周囲地盤を切削しながら掘削孔内を掘削翼(2)および撹拌翼(3)と共に掘進する。 In particular, the co-rotation prevention blade (4) is installed between the excavation blade (2) and the stirring blade (3) in a rotation-free state, and is longer than the excavation blade (2) and the stirring blade (3) and has a tip. The excavation blade (2) and the stirring blade (3) do not rotate even if the excavation blade (2) and the stirring blade (3) rotate and excavate in the ground together with the excavation shaft (1). Excavate with the excavation blade (2) and the stirring blade (3).

このため、硬質地盤に到達した時点においては、共回り防止翼(4)に大きな掘進抵抗が作用して施工能率が大きく低下するか、ソイルセメント柱の施工すら不可能になるおそれがある。 Therefore, when the ground reaches the hard ground, there is a possibility that a large excavation resistance acts on the co-rotation prevention blade (4) and the construction efficiency is greatly reduced, or even the construction of the soil cement column becomes impossible.

これらの課題を解決する装置として、例えば、特許文献２には、掘削ロッド(1)の先端とこれより上方位置にそれぞれ取り付けられ、掘削ロッド(1)と共に回転する掘削翼(2)および撹拌翼(4)、掘削翼(2)と撹拌翼(4)間に回転フリーな状態に設置された共回り防止翼(3)とを備えた地盤改良用掘削ロッドの発明が開示されている。 As a device for solving these problems, for example, in Patent Document 2, an excavation blade (2) and a stirring blade, which are attached to the tip of the excavation rod (1) and above the tip of the excavation rod (1) and rotate together with the excavation rod (1), respectively. (4), the invention of a ground improvement excavation rod provided with a co-rotation prevention blade (3) installed in a rotation-free state between the excavation blade (2) and the stirring blade (4) is disclosed.

特に、共回り防止翼(3)は、掘削ロッド(1)に回転フリーな状態に外接するボス(5)に固設されたブラケット(7)に水平状態から上方に回転自在に軸支され、かつ水平時は掘削翼(2)および撹拌翼(4)の前方まで伸びている。 In particular, the co-rotation prevention blade (3) is rotatably supported upward from the horizontal state by the bracket (7) fixed to the boss (5) that is external to the excavation rod (1) in a rotation-free state. And when horizontal, it extends to the front of the excavation blade (2) and the stirring blade (4).

また、共回り防止翼(3)が上方に回転して傾斜状態になったときに、共回り防止翼(3)をもとの水平状態に復帰させる付勢手段(9)と共回り防止翼(3)の水平状態を保持し、かつ一定量以上の回転力によって破断して共回り防止翼(3)の上方向への回転を許容するシャーピン(10)を備え、付勢手段(9)にはばね行数の小さいバネが用いられている。 In addition, when the co-rotation prevention wing (3) rotates upward and becomes inclined, the co-rotation prevention wing (3) is returned to the original horizontal state with the urging means (9) and the co-rotation prevention wing. Equipped with a shear pin (10) that maintains the horizontal state of (3) and allows the co-rotation prevention wing (3) to rotate upward by breaking due to a certain amount of rotational force or more, and urging means (9). A spring having a small number of spring rows is used for the spring.

特公昭５８－２９３７４号公報Special Publication No. 58-29374 特開２０１２－１８８８５６号公報Japanese Unexamined Patent Publication No. 2012-188856

しかし、特許文献２に開示された地盤改良用掘削ロッドは、施工中、付勢手段(9)がソイルセメント内にあるため、ソイルセメントのコンシステンシーの変化やばらつきによって、付勢手段(9)の性能（ばね定数）が変化する恐れがあり、共回り防止翼(3)が適切に作動しないおそれがあった。 However, in the excavation rod for ground improvement disclosed in Patent Document 2, since the urging means (9) is in the soil cement during construction, the urging means (9) is caused by changes and variations in the consistency of the soil cement. Performance (spring constant) may change, and the co-rotation prevention blade (3) may not operate properly.

また、施工後に、ソイルセメントが付着したまま硬化して付勢手段(9)が作動不能に陥るおそれがあった。かといって再使用時に硬化したソイルセメントを除去することは大変である。従って、施工後に、付着したソイルセメントを丁寧に除去しなければならず、多くの手間暇を必要とした。 In addition, after the construction, there was a risk that the soil cement would harden with the soil cement attached and the urging means (9) would become inoperable. However, it is difficult to remove the hardened soil cement during reuse. Therefore, after the construction, the adhering soil cement had to be carefully removed, which required a lot of time and effort.

さらに、図9,10に図示するように、付勢手段(9)が中空の円筒軸(15)内に内蔵された構成では、構造が複雑になりコストが嵩む等の課題が懸念される。 Further, as shown in FIGS. 9 and 10, in the configuration in which the urging means (9) is built in the hollow cylindrical shaft (15), there is a concern that the structure becomes complicated and the cost increases.

本発明は、以上の課題を解決するためになされたもので、掘削土の共回り現象を防止することはもとより、硬質地盤に突き当たった後も共回り防止翼の掘進抵抗を低減してソイルセメント鋼管杭の築造を効率的に継続できるようにした掘削撹拌ヘッドを提供することを目的とするものである。 The present invention has been made to solve the above problems, and not only prevents the co-rotation phenomenon of excavated soil, but also reduces the excavation resistance of the co-rotation prevention blade even after hitting hard ground, and soil cement. It is an object of the present invention to provide an excavation stirring head capable of efficiently continuing the construction of steel pipe piles.

本発明は、掘削ロッドに接続され、掘削翼と、撹拌翼と、共回り防止翼とを備え、先端部からセメントミルク等の固化材を吐出しつつ、地盤と撹拌混合してソイルセメント柱を築造し、前記ソイルセメント柱内に鋼管を埋設するために用いられる掘削撹拌ヘッドの発明であり、前記共回り防止翼は、共回り防止翼基部と共回り防止翼先端部とからなり、前記共回り防止翼先端部は前記共回り防止翼基部に対し、共回り防止翼の長手方向と直交する方向の支点ピンと共回り防止翼の長手方向と直交する方向のシャーピンを介して接続されており、前記共回り防止翼先端部が地盤から受ける抵抗力によって前記シャーピンに所定以上のせん断力が作用すると前記シャーピンが破断することで、前記共回り防止翼先端部が前記支点ピンを軸にして回転可能となっていることを特徴とするものである。 The present invention is connected to an excavation rod, includes an excavation blade, a stirring blade, and a co-rotation prevention blade, and while discharging a solidifying material such as cement milk from the tip, agitates and mixes with the ground to form a soil cement column. It is an invention of an excavation agitation head used for constructing and burying a steel pipe in the soil cement column. The tip of the anti-rotation blade is connected to the base of the anti-rotation blade via a fulcrum pin in a direction orthogonal to the longitudinal direction of the anti-rotation blade and a shear pin in a direction orthogonal to the longitudinal direction of the anti-rotation blade. When a shearing force of a predetermined value or more acts on the shear pin due to the resistance force received by the tip of the co-rotation prevention blade from the ground, the shear pin breaks, so that the tip of the co-rotation prevention blade can rotate about the fulcrum pin. It is characterized by being.

特に、シャーピンが所定以上のせん断力を受けると破断して、共回り防止翼先端部が支点ピンを軸に水平状態から上方(図１において反時計回り方向(矢印方向))に回転するように構成されていることで、鋼管ソイルセメント杭の施工中に硬質地盤に突き当たったとしても、共回り防止翼先端部が支点ピンを軸に回転して上向きになることで硬質地盤による抵抗力が低減されるため、鋼管ソイルセメント杭の施工を中断することなく継続して実施することができる。 In particular, when the shear pin receives a shearing force greater than a predetermined value, it breaks and the tip of the co-rotation prevention blade rotates upward (counterclockwise (arrow direction) in FIG. 1) from the horizontal state with the fulcrum pin as the axis. Due to the configuration, even if it hits the hard ground during the construction of the steel pipe soil cement pile, the resistance force due to the hard ground is reduced because the tip of the co-rotation prevention blade rotates around the fulcrum pin and turns upward. Therefore, the construction of the steel pipe soil cement pile can be continued without interruption.

なお、所定以上のせん断力とは、シャーピンが有するせん断強度を超える地盤の硬さによる掘進抵抗力のことであり、したがって、施工機(掘削機)の押込み能力に応じて最適なせん断強度を有するシャーピンを選択して使用することにより、鋼管ソイルセメント杭の施工をきわめて経済的かつ効率的に行うことができる。 The shear force above a predetermined level is a digging resistance force due to the hardness of the ground exceeding the shear strength of the shear pin, and therefore has an optimum shear strength according to the pushing capacity of the construction machine (excavator). By selecting and using shear pins, the construction of steel pipe soil cement piles can be performed extremely economically and efficiently.

また、前記共回り防止翼基部と前記共回り防止翼先端部に、前記共回り防止翼先端部が前記支点ピンを軸として上方に所定角度以上回転したときに相互に当接する当接部を形成し、前記当接部における摩擦抵抗により前記共回り防止翼先端部の回動を拘束するように構成することで、共回り防止翼先端部を上向きの状態に確実かつ強固に固定することができる。 Further, a contact portion is formed on the co-rotation prevention wing base and the co-rotation prevention wing tip so as to come into contact with each other when the co-rotation prevention wing tip rotates upward by a predetermined angle or more with the fulcrum pin as an axis. However, by configuring the tip of the co-rotation prevention blade to restrain the rotation of the tip of the co-rotation prevention blade by the frictional resistance at the contact portion, the tip of the co-rotation prevention blade can be securely and firmly fixed in an upward state. ..

これにより、特に鋼管ソイルセメント杭の掘削工程終了後、掘削撹拌ヘッドを引き上げる際に、共回り防止翼先端部が水平状態に復帰して掘削撹拌ヘッドの引き上げが困難になることはない。なお、上向きになった共回り防止翼先端部は、ワイヤー等を玉掛けして強く引っ張って当接部を引き離すことにより水平状態に復帰させることができる。 As a result, especially when the excavation stirring head is pulled up after the excavation process of the steel pipe soil cement pile is completed, the tip of the co-rotation prevention blade does not return to the horizontal state and it does not become difficult to pull up the excavation stirring head. The tip of the co-rotation prevention wing that has turned upward can be returned to the horizontal state by slinging a wire or the like and pulling strongly to pull the abutting portion apart.

また、相互に当接する当接部は、共回り防止翼基部と共回り防止翼先端部との対向面に、それぞれ支点ピンを中心に支点ピンの相反する周方向に徐々に隆起してテーパ状に形成してあれば、当接部どうしが強く当接し合うことにより共回り防止翼先端部の上方(図１において反時計回り方向(矢印方向))および下方(時計回り方向)の両方向への回転を強固に拘束することができる。 In addition, the abutting portions that come into contact with each other are tapered on the facing surfaces of the co-rotation prevention wing base and the co-rotation prevention wing tip, respectively, with the fulcrum pin as the center and gradually rising in the opposite circumferential directions of the fulcrum pin. If it is formed in the above direction, the abutting portions strongly abut against each other in both the upper direction (counterclockwise direction (arrow direction) in FIG. 1) and the lower (clockwise direction) of the co-rotation prevention wing tip. The rotation can be firmly restrained.

また、前記共回り防止翼先端部を前記共回り防止翼基部に対し、前記共回り防止翼の長手方向と直交する方向のシャーピンを介して接続し、前記共回り防止翼先端部が地盤から受ける抵抗力によって前記シャーピンに所定以上のせん断力が作用すると前記シャーピンが破断することで、前記共回り防止翼先端部が前記共回り防止翼基部から外れるように構成してもよい。 Further, the tip of the co-rotation prevention wing is connected to the co-rotation prevention wing base via a shear pin in a direction orthogonal to the longitudinal direction of the co-rotation prevention wing, and the co-rotation prevention wing tip is received from the ground. When a shearing force of a predetermined value or more acts on the shear pin due to the resistance force, the shear pin may be broken so that the tip portion of the co-rotation prevention blade is separated from the co-rotation prevention blade base.

本発明によれば、特に共回り防止翼先端部が共回り防止翼基部に対し、共回り防止翼の長手方向と直交する方向の支点ピンと共回り防止翼の長手方向と直交する方向のシャーピンを介して接続され、かつ前記共回り防止翼先端部が地盤から受ける抵抗力によって前記シャーピンに所定以上のせん断力が作用すると前記シャーピンが破断することで、前記共回り防止翼先端部が前記支点ピンを軸として上方に回転するように構成されていることで、鋼管ソイルセメント杭の施工中に硬質地盤に突き当たったとしても、共回り防止翼先端部が支点ピンを軸に上方に回転して硬質地盤による掘進抵抗が低減されるため、鋼管ソイルセメント杭の施工を中断することなく、継続して実施することができる。 According to the present invention, in particular, a fulcrum pin in a direction in which the tip of the co-rotation prevention blade is orthogonal to the longitudinal direction of the co-rotation prevention blade and a shear pin in a direction orthogonal to the longitudinal direction of the co-rotation prevention blade are provided with respect to the co-rotation prevention blade base. When a shearing force of a predetermined value or more acts on the shear pin due to the resistance force received from the ground by the tip of the co-rotation prevention wing, the shear pin is broken, so that the tip of the co-rotation prevention wing becomes the fulcrum pin. Because it is configured to rotate upward around the axis, even if it hits the hard ground during the construction of the steel pipe soil cement pile, the tip of the co-rotation prevention blade rotates upward around the fulcrum pin and is hard. Since the excavation resistance due to the ground is reduced, the construction of the steel pipe soil cement pile can be continued without interruption.

また、共回り防止翼先端部は、硬質地盤の掘進抵抗により回転して上向きになった後、共回り防止翼基部と共回り防止翼先端部双方の当接部が強く当接し合うことにより回転後の上向き状態に強固に固定することができる。これにより鋼管ソイルセメント杭の掘削工程終了後、掘削撹拌ヘッドを引き上げる際に共回り防止翼先端部が水平状態に復帰するようなことはなく、掘削撹拌ヘッドを地表までスムーズに引き上げることができる。 In addition, the tip of the co-rotation prevention wing rotates due to the excavation resistance of the hard ground and turns upward, and then the contact portions of both the base of the co-rotation prevention wing and the tip of the co-rotation prevention wing strongly abut each other to rotate. It can be firmly fixed to the rear upward state. As a result, after the excavation process of the steel pipe soil cement pile is completed, the tip of the co-rotation prevention blade does not return to the horizontal state when the excavation stirring head is pulled up, and the excavation stirring head can be smoothly pulled up to the ground surface.

本発明の掘削撹拌ヘッドの一実施形態を図示したものであり、図1(a)は正面図、図1(b)は図1(a)におけるイ－イ線断面図である。An embodiment of the excavation stirring head of the present invention is illustrated, FIG. 1 (a) is a front view, and FIG. 1 (b) is a cross-sectional view taken along the line 1 (a). 図２は、図１に図示する掘削撹拌ヘッドの要部拡大図であり、図2(a)は、図1(b)におけるロ部拡大図、図2(b)は図2(a)におけるハ部拡大断面図である。2 is an enlarged view of a main part of the excavation stirring head illustrated in FIG. 1, FIG. 2A is an enlarged view of a part B in FIG. 1B, and FIG. 2B is an enlarged view in FIG. 2A. C is an enlarged cross-sectional view of the part. 図3(a),(b),(c),(d)は、共回り防止翼の共回り防止翼先端部の動作を示す説明図である。3 (a), (b), (c), and (d) are explanatory views showing the operation of the tip of the co-rotation prevention blade of the co-rotation prevention blade. 本発明の掘削撹拌ヘッドの他の実施形態を図示したものであり、掘削撹拌ヘッドの正面図である。It is the figure which showed the other embodiment of the excavation agitation head of this invention, and is the front view of the excavation agitation head. 図5(a),(b)は、図４の実施形態における共回り防止翼の共回り防止翼先端部の動作を示す説明図である。5 (a) and 5 (b) are explanatory views showing the operation of the tip portion of the co-rotation prevention blade of the co-rotation prevention blade according to the embodiment of FIG. 図6(a),(b) ,(c)は、図４の実施形態における共回り防止翼の共回り防止翼先端部の動作を示す説明図である。6 (a), 6 (b), and 6 (c) are explanatory views showing the operation of the tip of the co-rotation prevention blade of the co-rotation prevention blade in the embodiment of FIG. 回転軸の先端部に取り付けられている掘削翼の変形例を図示したものであり、図7(a)は正面図、図7(b)は底面図である。A modified example of the excavation blade attached to the tip of the rotating shaft is illustrated, FIG. 7 (a) is a front view, and FIG. 7 (b) is a bottom view.

図１～図３は、本発明の一実施形態を図示したものである。図において、掘削撹拌ヘッド１は、回転軸２の先端部に掘削翼３、当該掘削翼３より上方に複数の撹拌翼４および共回り防止翼５をそれぞれ備えている。 1 to 3 show an embodiment of the present invention. In the figure, the excavation stirring head 1 is provided with an excavation blade 3 at the tip of a rotary shaft 2, a plurality of stirring blades 4 and a co-rotation prevention blade 5 above the excavation blade 3.

回転軸２は、先端部に地上より回転軸２内を通して注入される固化材(例えば、セメントミルク)の吐出口(図省略)を備え、また上端部に動力によって回転する掘削ロッド６に脱着自在に接続される接続部７を備えている。 The rotary shaft 2 is provided with a discharge port (not shown) for a solidifying material (for example, cement milk) injected from the ground through the rotary shaft 2 at the tip end portion, and is freely detachable from the excavation rod 6 rotated by power at the upper end portion. It is provided with a connection portion 7 connected to.

撹拌翼４は、回転軸２の軸方向に等間隔かつ回転軸２の軸直角方向に水平に設置され、回転軸２の両側に回転軸２の軸直角方向に対称に設置され、かつ回転軸２の周方向に平面視放射状に設置されており、これら回転軸２、掘削翼３および撹拌翼4は掘削ロッド６に接続され、掘削ロッド６と共に一体的に同時回転するように構成されている。 The stirring blades 4 are installed at equal intervals in the axial direction of the rotary shaft 2 and horizontally in the direction perpendicular to the axis of the rotary shaft 2, and are installed symmetrically on both sides of the rotary shaft 2 in the direction perpendicular to the axis of the rotary shaft 2. It is installed radially in a plan view in the circumferential direction of 2, and these rotation shafts 2, excavation blades 3, and stirring blades 4 are connected to excavation rods 6 and are configured to rotate integrally with excavation rods 6 at the same time. ..

共回り防止翼５は、一組の上下撹拌翼4,4間に回転軸２の軸直角方向に水平に設置され、かつ回転軸２の両側に対称に設置されている。また、共回り防止翼５は、共回り防止翼基部８とその先端側に位置する共回り防止翼先端部９とから構成され、かつ掘削翼３および撹拌翼４より長く構成されている。 The co-rotation prevention blade 5 is horizontally installed between a set of upper and lower stirring blades 4 and 4 in the direction perpendicular to the axis of the rotating shaft 2, and is symmetrically installed on both sides of the rotating shaft 2. Further, the co-rotation prevention blade 5 is composed of a co-rotation prevention blade base 8 and a co-rotation prevention blade tip 9 located on the tip side thereof, and is longer than the excavation blade 3 and the stirring blade 4.

共回り防止翼基部８は、回転軸２に回転フリーな状態に外接する回転スリーブ10と当該回転スリーブ10の側部に回転軸２の軸直角方向に水平に設置されたブラケット11とから構成され、かつブラケット11の先端部に遊嵌溝12が形成されている。遊嵌溝12は共回り防止翼基部８の先端方向に開口しかつ鉛直方向に連続して形成されている。 The co-rotation prevention wing base 8 is composed of a rotary sleeve 10 that is in contact with the rotary shaft 2 in a rotation-free state, and a bracket 11 horizontally installed on the side of the rotary sleeve 10 in a direction perpendicular to the axis of the rotary shaft 2. In addition, a free fitting groove 12 is formed at the tip of the bracket 11. The free fitting groove 12 opens in the tip direction of the co-rotation prevention blade base 8 and is continuously formed in the vertical direction.

共回り防止翼先端部９は、回転支持部9aと当該回転支持部9aの先端側に位置するカッター部9bとから回転軸２の軸方向に薄い板状に形成され、かつ回転軸２の軸直角方向に長い板状に形成され、さらに、カッター部9bの先端部に上端側から下端側にかけて円弧状をなす刃形9cが形成されている。 The co-rotation prevention blade tip 9 is formed in a thin plate shape in the axial direction of the rotation shaft 2 from the rotation support portion 9a and the cutter portion 9b located on the tip side of the rotation support portion 9a, and is the shaft of the rotation shaft 2. It is formed in the shape of a long plate in the perpendicular direction, and further, a blade shape 9c forming an arc shape from the upper end side to the lower end side is formed at the tip end portion of the cutter portion 9b.

また、回転支持部9aは、ブラケット11の遊嵌溝12に遊嵌され、かつブラケット11に共回り防止翼５の長手方向と直交する方向の支点ピン13によってカッター部9bと共に上下方向に回転フリーな状態に軸支されている。また、回転支持部9aは、共回り防止翼５の長手方向と直交する方向のシャーピン14によって、カッター部9bが共回り防止翼基部８の先端方向に水平に延在された状態に固定され、かつ掘削翼３および撹拌翼４の先端より前方に延在された状態に固定されている。 Further, the rotation support portion 9a is loosely fitted in the loose fitting groove 12 of the bracket 11, and is free to rotate in the vertical direction together with the cutter portion 9b by the fulcrum pin 13 in the direction orthogonal to the longitudinal direction of the co-rotation prevention blade 5 in the bracket 11. It is supported in a good state. Further, the rotation support portion 9a is fixed in a state in which the cutter portion 9b is horizontally extended in the tip direction of the co-rotation prevention blade base 8 by the shear pin 14 in the direction orthogonal to the longitudinal direction of the co-rotation prevention blade 5. Moreover, it is fixed in a state of extending forward from the tips of the excavation blade 3 and the stirring blade 4.

シャーピン14には、支点ピン13よりせん断強度が小さく、かつ所定以上のせん断力が作用することで破断する素材からなる支持ピンが使用されている。所定以上のせん断力とは、シャーピン14が有するせん断強度を超える地盤の硬さによる掘進抵抗力のことであり、したがって、施工機(掘削機)の押込み能力に応じて最適なせん断強度を有するシャーピン14を選択して使用することにより、鋼管ソイルセメント杭の施工をきわめて経済的かつ効率的に行うことができる。 The shear pin 14 uses a support pin made of a material that has a lower shear strength than the fulcrum pin 13 and breaks when a predetermined or higher shear force acts on it. The shear force above a predetermined level is the excavation resistance force due to the hardness of the ground exceeding the shear strength of the shear pin 14, and therefore, the shear pin having the optimum shear strength according to the pushing capacity of the construction machine (excavator). By selecting and using 14, the construction of steel pipe soil cement piles can be performed extremely economically and efficiently.

また、遊嵌溝12の内側面と回転支持部9aの側面には、共回り防止翼先端部９が支点ピン13を軸として上下方向(図１において反時計回り方向(矢印方向))に所定角度以上回転したときに相互に当接する当接部12aと9dが形成され、当該当接部12aと9c間の摩擦抵抗により共回り防止翼先端部９の回動が上方向(図１の矢印方向)の所定角度で、上方向および下方向の両方向への回転が拘束されるようになっている。 Further, on the inner side surface of the free fitting groove 12 and the side surface of the rotation support portion 9a, the co-rotation prevention blade tip portion 9 is predetermined in the vertical direction (counterclockwise direction (arrow direction) in FIG. 1) with the fulcrum pin 13 as the axis. Contact portions 12a and 9d that come into contact with each other when rotated by an angle or more are formed, and the rotation of the co-rotation prevention blade tip portion 9 is upward due to the frictional resistance between the contact portions 12a and 9c (arrow in FIG. 1). The rotation in both the upward and downward directions is restricted at a predetermined angle (direction).

当接部9dと12aは、それぞれ支点ピン13を中心に支点ピン13の相反する周方向に徐々に隆起してテーパ状に形成されている。例えば、当接部9dは支点ピン13を中心に共回り防止翼先端部９の上方向(図１の矢印方向)に徐々に隆起するテーパ状に形成され、当接部12aは下方向に徐々に隆起するテーパ状に形成されている。なお、当接部9dと12aは、共回り防止翼先端部９の両側の対称な位置に形成されていてもよい。 The abutting portions 9d and 12a are formed in a tapered shape by gradually rising in the opposite circumferential directions of the fulcrum pin 13 around the fulcrum pin 13, respectively. For example, the contact portion 9d is formed in a tapered shape that gradually rises in the upward direction (arrow direction in FIG. 1) of the co-rotation prevention blade tip portion 9 around the fulcrum pin 13, and the contact portion 12a gradually rises downward. It is formed in a tapered shape that rises to the surface. The contact portions 9d and 12a may be formed at symmetrical positions on both sides of the co-rotation prevention blade tip portion 9.

このような構成において、掘削翼３および撹拌翼４が回転軸２と共に地盤内を回転掘進しても、共回り防止翼5は、共回り防止翼先端部９のカッター部9bが周囲地盤内に食い込むことにより回転せず、掘削孔内を掘削翼３および撹拌翼４と共に地盤内を掘進する。これにより回転軸２先端の固化材吐出口より吐出された固化材と掘削土が撹拌翼４と共回り防止翼５によって撹拌混合されてソイルセメント柱が築造される。 In such a configuration, even if the excavation blade 3 and the stirring blade 4 rotate and dig in the ground together with the rotation shaft 2, the co-rotation prevention blade 5 has the cutter portion 9b of the co-rotation prevention blade tip 9 in the surrounding ground. It does not rotate by biting into it, and it digs into the ground together with the excavation blade 3 and the stirring blade 4 in the excavation hole. As a result, the solidifying material discharged from the solidifying material discharge port at the tip of the rotating shaft 2 and the excavated soil are agitated and mixed by the stirring blade 4 and the co-rotation prevention blade 5 to construct a soil cement column.

また、共回り防止翼先端部９のカッター部9bが硬質地盤に突き当たり、シャーピン14に所定以上のせん断力が作用することによりシャーピン14が破断すると、共回り防止翼先端部９は支持ピン13を軸に上方向に回転し、かつ上方向に所定角度以上回転した時点で回転支持部9aの当接部9dとブラケット11の当接部12aが強く当接し合い、その摩擦抵抗によって共回り防止翼先端部９の回動が拘束される。これにより、共回り防止翼５の周囲地盤への貫入抵抗が低減もしくは無くなるため、硬質地盤内をさらに掘進してソイルセメント柱が形成される。また、ソイルセメント柱の施工と同時にソイルセメント内に鋼管を沈設する施工方法においては、鋼管の沈設完了後、鋼管内をスムーズに掘削撹拌用ヘッド１を地上まで引き上げることができる。 Further, when the cutter portion 9b of the tip portion 9 of the co-rotation prevention blade hits the hard ground and the shear pin 14 is broken due to a shearing force of a predetermined value or more acting on the shear pin 14, the tip portion 9 of the co-rotation prevention blade 9 supports the support pin 13. When the shaft rotates upward and rotates upward by a predetermined angle or more, the contact portion 9d of the rotation support portion 9a and the contact portion 12a of the bracket 11 strongly abut each other, and the frictional resistance causes the co-rotation prevention blade. The rotation of the tip portion 9 is restricted. As a result, the penetration resistance of the co-rotation prevention blade 5 to the surrounding ground is reduced or eliminated, so that the soil cement column is formed by further digging in the hard ground. Further, in the construction method in which the steel pipe is sunk in the soil cement at the same time as the construction of the soil cement column, the excavation and agitation head 1 can be smoothly pulled up to the ground in the steel pipe after the sunk of the steel pipe is completed.

なお、共回り防止翼先端部９が支持ピン13を軸に上方向に回転した後の共回り防止翼５の長さＬは、撹拌翼４の長さと同程度か、あるいは掘削孔の内壁面にほぼ到達する程度の長さに構成されている(図１参照)。 The length L of the co-rotation prevention blade 5 after the co-rotation prevention blade tip 9 rotates upward around the support pin 13 is about the same as the length of the stirring blade 4, or the inner wall surface of the excavation hole. It is configured to have a length that almost reaches (see Fig. 1).

このような構成において、掘削撹拌ヘッド１を用いて鋼管ソイルセメント杭の施工を試験的に実施したところ、一定硬さ以上の硬質地盤では、共回り防止翼先端部９が支持ピン13を軸に上方に回転して折畳まれることで、共回り防止翼５の貫入抵抗が低減もしくは無くなり、これにより硬質地盤においても鋼管ソイルセメント杭を問題なく形成することができた。 In such a configuration, when the construction of the steel pipe soil cement pile was carried out on a trial basis using the excavation stirring head 1, in the hard ground having a certain hardness or more, the co-rotation prevention blade tip 9 is centered on the support pin 13. By rotating and folding upward, the penetration resistance of the co-rotation prevention blade 5 was reduced or eliminated, and as a result, the steel pipe soil cement pile could be formed without any problem even on hard ground.

図４～図６は、本発明の他の実施形態を図示したものであり、共回り防止翼先端部９の回転支持部9aがブラケット11の遊嵌溝12に遊嵌され、かつブラケット11に共回り防止翼５の長手方向と直交する方向のシャーピン14を介して接続されている。また、回転支持部9aの後端部が遊嵌溝12の底面に当接していることで、共回り防止翼先端部９のシャーピン14を軸とする上方向および下方向(時計回り方向および反時計回り方向(図４において矢印方向))への回転が阻止されている。 4 to 6 show another embodiment of the present invention, in which the rotation support portion 9a of the co-rotation prevention blade tip portion 9 is loosely fitted into the loose fitting groove 12 of the bracket 11 and is fitted into the bracket 11. It is connected via a shear pin 14 in a direction orthogonal to the longitudinal direction of the co-rotation prevention blade 5. Further, since the rear end portion of the rotation support portion 9a is in contact with the bottom surface of the free fitting groove 12, the upward and downward directions (clockwise direction and counterclockwise direction) about the shear pin 14 of the co-rotation prevention blade tip portion 9 are obtained. Rotation in the clockwise direction (arrow direction in FIG. 4) is blocked.

さらに、遊嵌溝12の底面部における、回転支持部9aの後端部上端のコーナ部9eと対向する位置に、支圧受け回転ピン15が共回り防止翼５の長手方向と直交する方向に取り付けられている。そして、当該支圧受け回転ピン15の側部に形成された嵌合溝15aに回転支持部9aの後端部上端のコーナ部9eが脱着可能に挿入されている。 Further, at the position of the bottom surface of the free fitting groove 12 facing the corner portion 9e at the upper end of the rear end portion of the rotation support portion 9a, the bearing rotation pin 15 is in the direction orthogonal to the longitudinal direction of the co-rotation prevention blade 5. It is attached. A corner portion 9e at the upper end of the rear end portion of the rotation support portion 9a is detachably inserted into the fitting groove 15a formed on the side portion of the bearing bearing rotation pin 15.

なお、支圧受け回転ピン15は、回転支持部9aより高強度の鋼材より形成され、また、滑らかに回転するように周囲に潤滑材(グリス)が充填されている。 The bearing bearing rotation pin 15 is formed of a steel material having a higher strength than the rotation support portion 9a, and is filled with a lubricant (grease) around it so as to rotate smoothly.

このような構成において、掘進時に共回り防止翼先端部９が地盤から上向きの掘進抵抗力を受け、シャーピン14に所定以上のせん断力が作用することにより、シャーピン14が破断して共回り防止翼先端部９が共回り防止翼基部８から外れるように構成されている。すなわち、掘進時に共回り防止翼先端部９が地盤から上向きの掘進抵抗力を受け、シャーピン14に所定以上のせん断力が作用するとシャーピン14は変形から破断に至り、これに伴い、共回り防止翼先端部９は、回転支持部9aの後端部上端のコーナ部9eを軸に支圧受け回転ピン15と共に上方向に回転しながら共回り防止翼基部８から離脱する(図6(a),(b),(c)参照)。 In such a configuration, the tip portion 9 of the co-rotation prevention blade receives an upward excavation resistance force from the ground during excavation, and a shear force of a predetermined value or more acts on the shear pin 14, so that the shear pin 14 is broken and the co-rotation prevention blade is broken. The tip portion 9 is configured to be detached from the co-rotation prevention blade base portion 8. That is, when the tip portion 9 of the co-rotation prevention blade receives an upward excavation resistance force from the ground during excavation, and a shear force of a predetermined value or more acts on the shear pin 14, the shear pin 14 is deformed to break, and the co-rotation prevention blade is accompanied by this. The tip portion 9 separates from the co-rotation prevention wing base 8 while rotating upward together with the bearing bearing rotation pin 15 around the corner portion 9e at the upper end of the rear end portion of the rotation support portion 9a (FIG. 6 (a), See (b), (c)).

このように、高強度の鋼材からなる支圧受け回転ピン15が取り付けられていることで、繰り返し使用される共回り防止翼５の共回り防止翼基部８の損傷を軽減することができる。 By attaching the bearing bearing rotation pin 15 made of a high-strength steel material in this way, it is possible to reduce damage to the co-rotation prevention blade base 8 of the co-rotation prevention blade 5 that is repeatedly used.

なお、共回り防止翼先端部９が共回り防止翼基部８から離脱した後の共回り防止翼５の長さＬは、撹拌翼４の長さと同程度か、あるいは掘削孔の内壁面にほぼ到達する程度の長さに構成されている(図参４照)。 The length L of the co-rotation prevention blade 5 after the co-rotation prevention blade tip 9 is separated from the co-rotation prevention blade base 8 is about the same as the length of the stirring blade 4, or almost on the inner wall surface of the excavation hole. It is configured to be long enough to reach (see Figure 4).

図7(a),(b)は、回転軸２の先端部に取り付けられている掘削翼３の変形例を図示したものであり、掘削翼３として回転軸２の軸方向にスパイラル状に形成された掘削翼を用いることで、掘進力と撹拌混合力を高めることができる。 FIGS. 7 (a) and 7 (b) show a modified example of the excavation blade 3 attached to the tip of the rotary shaft 2, and the excavation blade 3 is formed in a spiral shape in the axial direction of the rotary shaft 2. By using the excavated blades, the excavation force and the stirring and mixing force can be increased.

このような構成において、鋼管ソイルセメント杭の施工を試験的に実施したところ、一定硬さ以上の硬質地盤では、シャーピン14が破断して、共回り防止翼先端部９が共回り防止翼基部８から離脱することで、共回り防止翼５の貫入抵抗が低減もしくは無くなり、これにより硬質地盤においても鋼管ソイルセメント杭を問題なく形成することができた。 In such a configuration, when the construction of the steel pipe soil cement pile was carried out on a trial basis, the shear pin 14 was broken and the co-rotation prevention wing tip 9 was the co-rotation prevention wing base 8 in the hard ground having a certain hardness or more. By separating from the above, the penetration resistance of the co-rotation prevention blade 5 was reduced or eliminated, and as a result, the steel pipe soil cement pile could be formed without any problem even on hard ground.

本発明は、特に硬質地盤に到達後も中断することなく連続して鋼管ソイルセメント杭の施工を継続して施工することができる。 INDUSTRIAL APPLICABILITY According to the present invention, it is possible to continuously construct a steel pipe soil cement pile without interruption even after reaching a particularly hard ground.

１掘削撹拌ヘッド
２回転軸
３掘削翼
４撹拌翼
５共回り防止翼
６掘削ロッド
７接続部
８共回り防止翼基部
９共回り防止翼先端部
9a 回転支持部
9b カッター部
9c 刃形
9d 当接部
9e コーナ部
10 回転スリーブ
11 ブラケット
12 遊嵌溝
12a 当接部
13 支点ピン
14 シャーピン
15 支圧受け回転ピン 1 Excavation stirring head 2 Rotating shaft 3 Excavation blade 4 Stirring blade 5 Co-rotation prevention blade 6 Excavation rod 7 Connection part 8 Co-rotation prevention blade base 9 Co-rotation prevention blade tip
9a Rotation support
9b Cutter part
9c blade shape
9d contact part
9e corner section
10 rotating sleeve
11 Bracket
12 Free fit groove
12a abutment
13 fulcrum pin
14 Sharpin
15 Pressure receiving rotary pin

Claims

It is connected to an excavation rod and is equipped with an excavation blade, a stirring blade, and a co-rotation prevention blade. In the excavation stirring head used for burying a steel pipe, the co-rotation prevention blade is composed of a co-rotation prevention blade base and a co-rotation prevention blade tip, and the co-rotation prevention blade tip is the co-rotation prevention blade. It is connected to the base via a fulcrum pin in a direction orthogonal to the longitudinal direction of the co-rotation prevention blade and a shear pin in a direction orthogonal to the longitudinal direction of the co-rotation prevention blade, and the tip portion of the co-rotation prevention blade is the ground. When a shearing force equal to or higher than a predetermined value acts on the shear pin due to the resistance force received from the shear pin, the shear pin is broken, so that the tip of the co-rotation prevention blade can rotate around the fulcrum pin, and the co-rotation prevention blade can be rotated. The base portion and the tip portion of the co-rotation prevention blade are formed with a contact portion that abuts each other when the tip portion of the co-rotation prevention blade rotates about a predetermined angle or more with the fulcrum pin as an axis, and the contact portion is formed. An excavation agitation head characterized in that the rotation of the tip of the co-rotation prevention blade is restrained by the frictional resistance in the portion.

It is connected to an excavation rod and is equipped with an excavation blade, a stirring blade, and a co-rotation prevention blade. In the excavation stirring head used for burying a steel pipe, the co-rotation prevention blade is composed of a co-rotation prevention blade base portion and a co-rotation prevention blade tip portion, and the co-rotation prevention blade tip portion is the co-rotation prevention blade base portion. On the other hand, it is connected via a shear pin in a direction orthogonal to the longitudinal direction of the co-rotation prevention blade, and when the shear force of a predetermined value or more acts on the shear pin due to the resistance force received from the ground by the tip of the co-rotation prevention blade. An excavation agitation head characterized in that the tip portion of the co-rotation prevention blade is detached from the co-rotation prevention blade base portion by breaking the shear pin.