JP2008075336A - Construction method for precast pile - Google Patents

Construction method for precast pile Download PDF

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JP2008075336A
JP2008075336A JP2006255692A JP2006255692A JP2008075336A JP 2008075336 A JP2008075336 A JP 2008075336A JP 2006255692 A JP2006255692 A JP 2006255692A JP 2006255692 A JP2006255692 A JP 2006255692A JP 2008075336 A JP2008075336 A JP 2008075336A
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steel pipe
soil cement
pile
pipe pile
excavation
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JP4872561B2 (en
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Masahiro Hayashi
正宏 林
Kimihisa Takano
公寿 高野
Hiroshi Wakiya
泰士 脇屋
Kazuomi Ichikawa
和臣 市川
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JFE Steel Corp
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JFE Steel Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method for a precast pile for filling an improving material into an outer peripheral part of the precast pile securely and easily without filling it into the inside of the precast pile and paying great costs of an excavation device and construction. <P>SOLUTION: After digging the ground 3 to construct the precast pile 8 into the ground, a solidifying agent is poured into the digged ground 3, the poured solidifying agent and sediment are stirred to prepare the improving material 5 and construct the precast pile 8 having a blocked lower end part into the improving material 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、先堀り工法を用いて既製杭を施工する方法に関する。なお、本発明において既製杭とは、中空の、鋼管杭やコンクリート杭（鉄筋コンクリート杭（RC杭）、プレストレストコンクリート（PC）杭、高強度プレストレストコンクリート（PHC）杭、外殻鋼管付きコンクリート（SC）杭、高強度コンクリート拡径杭（ST）杭、鉄筋または平鋼を入れたコンクリート（PRC）杭等を含む）等を示す。   The present invention relates to a method for constructing a ready-made pile using a pre-drilling method. In the present invention, the ready-made pile means a hollow steel pipe pile or concrete pile (reinforced concrete pile (RC pile), prestressed concrete (PC) pile, high strength prestressed concrete (PHC) pile, concrete with outer shell steel pipe (SC)) Pile, high-strength concrete expanded pile (ST) pile, concrete (PRC) pile with reinforcing steel or flat steel etc.) etc. are shown.

市街地等における既製杭の施工方法としては、低振動、低騒音で、かつ狭いスペースで施工できる埋込み杭工法が、一般的に採用されている。この埋込み杭工法には、さらに先掘り工法、中掘り工法等がある。   As a method for constructing ready-made piles in an urban area or the like, an embedded pile method that can be constructed in a narrow space with low vibration and noise is generally adopted. This embedded pile method further includes a pre-digging method, a medium digging method, and the like.

この内、先掘り工法は、スパイラルオーガーあるいは先端に掘削ヘッドを設けた掘削ロッド等の掘削装置で、地盤中に穴を先に掘削し、その後、当該穴に既製杭を建て込む工法である。通常、掘削ヘッド部分等からセメントミルク等の固化材を、既製杭を建て込む穴に注入し、土砂と攪拌・混合したソイルセメント等の中へ既製杭を沈設していくもので、ソイルセメント等の固化により既製杭を掘削穴中に固定し、支持力を得る。支持層における先端支持力を増すため、既製杭の下端に、富配合のセメントミルクもしくはモルタル等を充填し、先端根固め部を形成することも多い。   Among these, the pre-digging method is a method of excavating a hole in the ground first by a drilling device such as a spiral auger or a drilling rod provided with a drilling head at the tip, and then building a ready-made pile in the hole. Normally, cement milk or other solidifying material is poured from the excavation head into a hole into which a ready-made pile is to be built, and the ready-made pile is set in a soil cement that has been stirred and mixed with earth and sand. The ready-made piles are fixed in the excavation holes by solidifying the and the support force is obtained. In order to increase the tip support force in the support layer, the bottom end of the ready-made pile is often filled with rich blended cement milk or mortar to form a tip root solidified portion.

しかしこの工法の場合、ソイルセメント等が中空既製杭の中空部分（以降、既製杭の内部と呼ぶ）にも充填され、固化材の使用量が増大しコストが上昇するという問題がある。既製杭の内部に充填されたソイルセメントは、杭の剛性と杭の支持力には影響しないので、既製杭の内部にソイルセメントを充填しなくても、杭の性能は全く変わらない。そして、この問題は、杭径が大きくなればなる程、中空部分が増加する為に大きくなる。   However, in the case of this construction method, there is a problem that soil cement or the like is filled in the hollow portion of the hollow ready-made pile (hereinafter referred to as the inside of the ready-made pile), and the amount of the solidified material increases and the cost increases. Since the soil cement filled in the ready-made pile does not affect the rigidity of the pile and the supporting force of the pile, the performance of the pile is not changed at all even if the soil cement is not filled in the ready-made pile. And this problem becomes large because the hollow portion increases as the pile diameter increases.

そこで、この問題を克服する為、特許文献１、特許文献２および特許文献３の発明がなされている。特許文献１には、中空部を貫通する掘削装置の回転軸に杭の中空部を閉じるシャッタアを設け、杭の内部に混合してなるソイルセメントの流入を阻止する技術が開示されている。また、特許文献２には、中空部を貫通する掘削装置の回転軸に逆流装置を設け、杭の内部に混合してなるソイルセメントの流入を阻止する技術が開示されている。さらに、特許文献３には、スラリー状の固化材を鋼管外周面に限定して吐出できる掘削装置の技術が開示されている。
特開昭６３−２７７３１８号公報 特開昭６３−２３３１９０号公報 特開２００１−０６４９７０号公報 In order to overcome this problem, the inventions of Patent Document 1, Patent Document 2 and Patent Document 3 have been made. Patent Document 1 discloses a technique of providing a shutterer that closes a hollow portion of a pile on a rotating shaft of an excavating apparatus that penetrates the hollow portion, and preventing inflow of soil cement formed by mixing the inside of the pile. Patent Document 2 discloses a technique for preventing a soil cement from flowing into a pile by providing a backflow device on the rotary shaft of the excavator that penetrates the hollow portion. Furthermore, Patent Document 3 discloses a technique of an excavator that can discharge a slurry-like solidified material to the outer peripheral surface of a steel pipe.
JP-A 63-277318 JP-A-63-233190 JP 2001-064970 A

特許文献１、特許文献２および特許文献３の何れの技術も、掘削装置の攪拌軸や攪拌翼に特殊な装置を付加したり、特殊な構造とする必要があり、掘削装置の製作に膨大なコストがかかる。さらに、特許文献１の技術では、地中深くの圧力に耐えるシャッタアの構造は、かなり剛性の大きなものが必要となり、装置が大がかりになる。一方、特許文献２の技術では、施工において逆流スパイラルと管内面にはある程度の隙間が必要であり、その隙間を通してソイルセメントが上昇し、杭内部にも充填されてしまうおそれがある。   In any of the techniques of Patent Document 1, Patent Document 2, and Patent Document 3, it is necessary to add a special device to the stirring shaft and the stirring blade of the drilling device, or to have a special structure, which is enormous in manufacturing the drilling device. costly. Furthermore, in the technique of Patent Document 1, the shutter structure that can withstand pressure deep in the ground needs to be quite rigid, and the apparatus becomes large. On the other hand, in the technique of Patent Document 2, a certain amount of clearance is required between the backflow spiral and the inner surface of the pipe in construction, and the soil cement may rise through the clearance and may be filled in the pile.

あるいは、特許文献３の技術では、固化材（セメントミルク）が地中深くで吐出されるため、既製杭の外周面にソイルセメントが適切に配置される可能性は低い。特に、ソイルセメントの流動性が低い場合、既製杭の外周部にソイルセメントが配置されるように施工するのは難しくなる。   Or in the technique of patent document 3, since solidification material (cement milk) is discharged deep underground, possibility that soil cement will be appropriately arrange | positioned on the outer peripheral surface of a ready-made pile is low. In particular, when the fluidity of the soil cement is low, it is difficult to construct so that the soil cement is disposed on the outer peripheral portion of the ready-made pile.

本発明は、上記問題を解決する為になされたものであって、掘削装置や施工のために膨大なコストをかけずに、改良体（ソイルセメント等）を、既製杭の内部には充填せずに既製杭の外周部に確実かつ容易に充填することができる既製杭の施工方法を提供する。   The present invention has been made in order to solve the above-described problems, and an improved body (soil cement or the like) is filled in an existing pile without incurring enormous costs for excavation equipment or construction. The construction method of the ready-made pile which can be reliably and easily filled into the outer peripheral part of a ready-made pile is provided.

（１）上記の課題を解決するため、本発明に係る既製杭の施工方法は、既製杭を建て込む地盤を掘削した後、掘削された地盤中に固化材を注入し、前記注入された固化材と土砂とを攪拌して改良体を造成し、さらに、前記造成された改良体に下端部が閉塞した既製杭を建て込むことを特徴とする。
（２）上記の課題を解決するため、本発明に係る既製杭の施工方法は、既製杭を建て込む地盤を掘削した後、掘削された地盤中に固化材を注入し、前記注入された固化材と土砂とを攪拌して改良体を造成し、さらに、前記造成された改良体に、鋼管杭の内部に配置された掘削ロッドにより下端部が閉塞した既製杭を建て込むことを特徴とする。 (1) In order to solve the above-mentioned problem, the method for constructing a ready-made pile according to the present invention is to inject a solidifying material into the excavated ground after excavating the ground into which the ready-made pile is built, and the injected solidified A material and earth and sand are agitated to form an improved body, and a pre-made pile having a closed lower end is built into the improved body.
(2) In order to solve the above-mentioned problem, the method for constructing a ready-made pile according to the present invention excavates the ground into which the ready-made pile is built, and then injects a solidifying material into the excavated ground, and the injected solidification A material and earth and sand are agitated to form an improved body, and a pre-made pile whose lower end is closed by a drilling rod disposed inside the steel pipe pile is built into the improved body that has been created. .

本発明によれば、固化材と土砂とを混合した改良体（例えば、セメントミルクと土砂から造成されるソイルセメント）を掘削穴下部で造成した後に、下端部が閉塞した既製杭を建て込むという簡略な方法で、既製杭の外周面における支持力性能を向上させると共に、杭剛性もしくは荷重支持には関与しない余分な改良体を既製杭内部に充填せずに施工することができる。この為、固化材の余分な注入を防ぐことができ、施工コストを大きく下げることができる。さらに、固化材の注入量を少なくできることから、改良体を含む土砂等の排出が減るので、産業廃棄物の処理が減り環境への負荷を少なくすることができる。   According to the present invention, after an improved body (for example, a soil cement formed from cement milk and earth and sand) mixed with a solidified material and earth and sand is formed at the bottom of the excavation hole, a ready-made pile whose lower end is closed is built. In a simple manner, the bearing capacity performance on the outer peripheral surface of the ready-made pile can be improved, and an extra improved body that does not participate in pile rigidity or load support can be applied without filling the ready-made pile. For this reason, excessive injection | pouring of a solidification material can be prevented and construction cost can be reduced significantly. Furthermore, since the injection amount of the solidifying material can be reduced, the discharge of earth and sand including the improved body is reduced, so that the treatment of industrial waste is reduced and the burden on the environment can be reduced.

本発明について、図を参照しつつ詳細に説明する。   The present invention will be described in detail with reference to the drawings.

（ａ）施工方法の例：第１の実施の形態
先ず、本発明に係る既製杭の施工方法の一例を、第１の実施の形態として説明する。図１は、本実施の形態に係る施工手順を、模式的に示す断面図である。図１（１）から図１（７）までの番号順が、施工の順番を示しており、この番号に沿って、第１の実施の形態を説明する。 (A) Example of construction method: 1st embodiment First, an example of the construction method of the ready-made pile concerning this invention is demonstrated as 1st Embodiment. FIG. 1 is a cross-sectional view schematically showing a construction procedure according to the present embodiment. The order of numbers from FIG. 1 (1) to FIG. 1 (7) indicates the order of construction, and the first embodiment will be described along these numbers.

この第１の実施の形態においては、中空の鋼管杭８を掘削ロッド１１、１２を用いて地盤３に、先堀り工法で埋設する。鋼管杭８の外周部はソイルセメント５で改良し、鋼管杭８の先端根固め部は富配合ソイルセメント６で形成する。掘削ロッド１２の先端部には、鋼管杭８の下端部を閉塞する機構が設けられており、この機構により鋼管杭８の下端部を閉塞することが可能となっている。また、掘削ロッド１１、１２の先端部には、従来と同様に、掘削液や固化材を噴出可能な噴出孔が設けられていて、地盤中や泥土中に注入可能となっている。なお、固化材としては、実際の杭の施工においてはセメントミルクの使用頻度が最も高いので、セメントミルクを用いた場合で説明する。また、掘削液としては、ソイルセメント５および富配合ソイルセメント６の強度へ影響の少ない水を用いた場合で説明する。固化材と攪拌する土砂としては、排土を発生させない為に、地盤３が掘削されて発生する土砂を用いた場合で説明する。その為、セメントミルクと地盤３の土砂と水とを攪拌して造成されるソイルセメント５が改良体となる。さらに、施工装置は、通常の先堀り工法で用いられる3点式杭打ち機を用いる。   In this 1st Embodiment, the hollow steel pipe pile 8 is embed | buried by the excavation method in the ground 3 using the excavation rods 11 and 12. FIG. The outer periphery of the steel pipe pile 8 is improved with the soil cement 5, and the tip rooted portion of the steel pipe pile 8 is formed with the rich blended soil cement 6. A mechanism for closing the lower end of the steel pipe pile 8 is provided at the tip of the excavation rod 12, and the lower end of the steel pipe pile 8 can be closed by this mechanism. Moreover, the tip of the excavation rods 11 and 12 is provided with an ejection hole through which excavation fluid and a solidified material can be ejected, as in the prior art, and can be injected into the ground or mud. In addition, as a solidification material, since the use frequency of cement milk is the highest in construction of an actual pile, it demonstrates by the case where cement milk is used. Further, as the drilling fluid, the case where water having little influence on the strength of the soil cement 5 and the rich blended soil cement 6 is used will be described. As the earth and sand to be agitated with the solidifying material, a case will be described in which earth and sand generated by excavation of the ground 3 is used in order to prevent generation of soil. Therefore, the soil cement 5 formed by stirring the cement milk, the earth and sand of the ground 3 and the water is an improved body. Furthermore, the construction equipment uses a three-point pile driver used in a normal tip excavation method.

（１）先ず、掘削ロッド１１のみを地盤３に回転貫入させ、予め地盤３を泥土化させる。回転貫入した地盤３に、掘削ロッド１１の先端部の噴出孔から水を注入しながら掘削を行う。この時、排土は殆ど行わないように施工する。その為、掘削後の掘削穴２は、地盤３の土砂と水が混合されてできた泥土４で満たされる。   (1) First, only the excavation rod 11 is rotated and penetrated into the ground 3, and the ground 3 is mud beforehand. Excavation is performed while injecting water from the ejection hole at the tip of the excavation rod 11 into the ground 3 that has been rotated and penetrated. At this time, construction should be done so that little earth is removed. Therefore, the excavation hole 2 after excavation is filled with mud 4 made by mixing the earth and sand of the ground 3 and water.

（２）次に、支持層まで掘削を行ったら、掘削ロッド１１の貫入を停止する。   (2) Next, after excavation to the support layer, the penetration of the excavation rod 11 is stopped.

（３）そして、掘削ロッド１１の先端の噴出孔から、掘削穴２の底部にセメントミルクを注入する。そして、掘削ロッド１１を回転させながら所定ストロークだけ上下動させて、注入したセメントミルクと泥土４とを攪拌混合してソイルセメント５にする。   (3) Then, cement milk is injected into the bottom of the excavation hole 2 from the ejection hole at the tip of the excavation rod 11. Then, the excavation rod 11 is rotated up and down by a predetermined stroke, and the injected cement milk and mud 4 are stirred and mixed to form a soil cement 5.

セメントミルクの注入量は、従来技術のように掘削した全ての深さがソイルセメント５で満たされるような量とするのでは無く、図１（３）に例示するように、掘削穴２の底から途中の深さまでがソイルセメント５で満たされるように注入する。即ち、鋼管杭８の施工が完成した時に、鋼管杭８の内部にはソイルセメント５が殆ど無く、かつ鋼管杭８の外周部をソイルセメント５が充填するのに十分な量であれば良い。なお、セメントミルクの注入量は、埋設する鋼管杭８の長さや内径、もしくは施工仕様によって、適宜決定する。   The injection amount of the cement milk is not set so that the entire depth of excavation is filled with the soil cement 5 as in the prior art, but as illustrated in FIG. Until the middle depth is filled with the soil cement 5. That is, when the construction of the steel pipe pile 8 is completed, there is almost no soil cement 5 inside the steel pipe pile 8, and it is sufficient if the amount is sufficient for the soil cement 5 to fill the outer periphery of the steel pipe pile 8. Note that the amount of cement milk to be injected is appropriately determined according to the length and inner diameter of the steel pipe pile 8 to be buried or the construction specifications.

（４）上記のように掘削とソイルセメント５の造成が完了したら、掘削ロッド１１を引き抜く。ソイルセメント５の表面Aを境に、掘削穴２の下部はソイルセメント５、掘削穴２の上部は泥土４で満たされる。   (4) When the excavation and the formation of the soil cement 5 are completed as described above, the excavation rod 11 is pulled out. With the surface A of the soil cement 5 as a boundary, the lower part of the excavation hole 2 is filled with the soil cement 5 and the upper part of the excavation hole 2 is filled with the mud 4.

（５）上記泥土４とソイルセメント５の中に、自重沈設および回転圧入によって、掘削ロッド１２と共に鋼管杭８を建て込む。この時、掘削ロッド１２の先端部に備えられた、鋼管杭８の下端部を閉塞する機構により、鋼管杭８の下端部は閉塞している。この鋼管杭８の閉塞した下端部により、鋼管杭８の沈設の際にソイルセメント５の表面Aに対し、鉛直方向下向きの圧力をかけることができる。その圧力により、掘削穴２の下部にあるソイルセメント５は、鋼管杭８の下端と掘削穴２の底との隙間から、鋼管杭８の外周部へ押し上げられる。さらに、鋼管杭８の外周部の上部にある泥土４を上方に押し上げ、鋼管杭８の外周部はそのほぼ全長がソイルセメント５で満たされる。   (5) The steel pipe pile 8 is built in the mud 4 and the soil cement 5 together with the excavating rod 12 by self-weight settling and rotary press-fitting. At this time, the lower end portion of the steel pipe pile 8 is closed by a mechanism provided at the distal end portion of the excavation rod 12 to close the lower end portion of the steel pipe pile 8. Due to the closed lower end portion of the steel pipe pile 8, a vertical downward pressure can be applied to the surface A of the soil cement 5 when the steel pipe pile 8 is set. Due to the pressure, the soil cement 5 at the bottom of the excavation hole 2 is pushed up to the outer peripheral portion of the steel pipe pile 8 from the gap between the lower end of the steel pipe pile 8 and the bottom of the excavation hole 2. Furthermore, the mud 4 at the upper part of the outer peripheral part of the steel pipe pile 8 is pushed upward, and the outer peripheral part of the steel pipe pile 8 is almost filled with the soil cement 5.

（６）鋼管杭８を所定の深さまで建て込めば、掘削穴２の下部にあったソイルセメント５により、鋼管杭８の外周部のほぼ全長をソイルセメント５で満たした状態となる。この状態で、鋼管杭８の先端部の閉塞を解くと共に、鋼管杭８の下端部に富配合のセメントミルクを注入する。そして、掘削ロッド１２を回転させながら所定ストロークだけ上下動させて、注入した富配合のセメントミルクとソイルセメント５とを攪拌混合して、先端根固め用の富配合ソイルセメント６を造成する。この時、掘削ロッド１２と同時に鋼管杭８も上下動や回転させると、より良好な富配合ソイルセメント６が造成される。   (6) If the steel pipe pile 8 is built to a predetermined depth, the soil cement 5 located at the lower part of the excavation hole 2 will fill the substantially entire length of the outer peripheral portion of the steel pipe pile 8 with the soil cement 5. In this state, the blockage of the tip of the steel pipe pile 8 is released, and a rich blended cement milk is injected into the lower end of the steel pipe pile 8. Then, the excavation rod 12 is rotated up and down by a predetermined stroke, and the injected rich blended cement milk and the soil cement 5 are stirred and mixed to form the rich blended soil cement 6 for root hardening. At this time, if the steel pipe pile 8 is moved up and down or rotated simultaneously with the excavating rod 12, a better blended soil cement 6 is formed.

（７）先端根固め用の富配合ソイルセメント６が造成できたら、掘削ロッド１２を引き抜き、ソイルセメント５と富配合ソイルセメント６を固化させる。   (7) When the rich blended soil cement 6 for root hardening is formed, the excavation rod 12 is pulled out, and the soil cement 5 and the rich blended soil cement 6 are solidified.

なお、本実施の形態において、ソイルセメント５は、かけられた圧力により上昇しやすいように、流動性が高いものの方が好ましい。具体的には、セメントミルクの水セメント比W/Cを100〜200質量%程度として、調整する。   In the present embodiment, it is preferable that the soil cement 5 has a high fluidity so that the soil cement 5 can be easily raised by the applied pressure. Specifically, the water-cement ratio W / C of cement milk is adjusted to about 100 to 200% by mass.

また、上記（５）で鋼管杭８を建て込む際には、鋼管杭８の下端からソイルセメント５が入り込まないように、杭内部には水７６を注入して、圧力のバランスをとる等、の対応をとるのが望ましい。   Moreover, when building the steel pipe pile 8 in the above (5), water 76 is injected into the pile so that the soil cement 5 does not enter from the lower end of the steel pipe pile 8, and the balance of pressure is balanced, It is desirable to take this measure.

本実施の形態によれば、先端根固め施工する前に、ソイルセメント５を掘削穴２の下部で造成し、そのソイルセメント５に対し下端部が閉塞した鋼管杭８を建て込むことにより、鋼管杭８の内部に充填することなく鋼管杭８の外周部へ押し上げるといった簡略な方法で、鋼管杭８の外周面支持力性能を向上させ、かつ鋼管杭８内部にあるソイルセメント５を減少させ、さらには無くすことができる。   According to the present embodiment, the steel pipe 5 is formed at the lower portion of the excavation hole 2 and the steel pipe pile 8 whose lower end portion is closed is built in the soil cement 5 before the tip rooting work is performed. With a simple method of pushing up to the outer periphery of the steel pipe pile 8 without filling the inside of the pile 8, the outer peripheral surface bearing capacity performance of the steel pipe pile 8 is improved, and the soil cement 5 inside the steel pipe pile 8 is reduced, Furthermore, it can be eliminated.

本実施の形態の工程（５）における、掘削ロッド１２の先端部に備えられた、鋼管杭８の下端部を閉塞する機構は、例えば、図２に模式的に示した機構が考えられる。ここで、図２（ａ）と（ｂ）共に、工程（５）にて建て込み中の掘削ロッド１２の先端部（即ち、鋼管杭８の下端部）の状態を、拡大した断面図にて示している。   As the mechanism for closing the lower end portion of the steel pipe pile 8 provided at the tip portion of the excavation rod 12 in the step (5) of the present embodiment, for example, the mechanism schematically shown in FIG. Here, in both FIG. 2 (a) and (b), in the expanded sectional view, the state of the front-end | tip part (namely, lower end part of the steel pipe pile 8) of the excavation rod 12 currently built in process (5) is shown. Show.

図２（ａ）は、掘削ロッド１２の先端部で、掘削ビット１２ａの少し上方に、蓋１２ｂを取り付けた例である。この蓋１２ｂは、鋼管杭８の内径とほぼ同じ直径の円板で、中心部が掘削ロッド１２に取り付けられ、その中心部は掘削ロッド１２が上下移動および回転が可能な機構となっている。また、縁にはゴムパッキン１２ｃを備えている。蓋１２ｂの円板部分で鋼管杭８の下端部からソイルセメント５が内部へ進入するのを防ぐ。また、このゴムパッキン１２ｃは、油圧式や回転すると鋼管杭８からはずれる等の構造とし、先端根固め部を形成する時には、鋼管杭８の下端部の閉塞が解ける構造とするのが、より好ましい。掘削ロッド１２を鋼管杭８の内部に配置すると、図２（ａ）に示すように、蓋１２ｂは鋼管杭８の下端部を閉塞する構造となる。   FIG. 2A shows an example in which a lid 12b is attached to the tip of the excavation rod 12 slightly above the excavation bit 12a. The lid 12b is a disc having a diameter substantially the same as the inner diameter of the steel pipe pile 8, and a central portion is attached to the excavation rod 12, and the central portion is a mechanism that allows the excavation rod 12 to move up and down and rotate. Further, a rubber packing 12c is provided at the edge. The soil cement 5 is prevented from entering from the lower end of the steel pipe pile 8 at the disc portion of the lid 12b. Further, the rubber packing 12c is preferably structured such as to be detached from the steel pipe pile 8 when it is hydraulic or rotated, and when the tip rooted portion is formed, it is preferable that the lower end of the steel pipe pile 8 is unblocked. . When the excavating rod 12 is disposed inside the steel pipe pile 8, the lid 12b has a structure for closing the lower end portion of the steel pipe pile 8 as shown in FIG.

図２（ｂ）は、掘削ロッド１２の先端部で、掘削ビット１２ａの少し上方に、ゴム風船１２ｄを取り付けた例である。この例の場合は、ゴム風船１２ｄの少し上方の鋼管杭の内周面に、突起８１も設けておく。ゴム風船１２ｄは、鋼管杭８の内径とほぼ同じ外径のドーナツ状であり、中心の中空部が掘削ロッド１２ｄに固定されている。このゴム風船１２ｄで、鋼管杭８の先端部からソイルセメント５が内部へ進入するのを防ぐと共に、掘削ロッド１２の上下方向の移動を可能とする。一方、鋼管杭８の内周の突起８１は、鋭角な部位を下方、つまりゴム風船１２ｄの方向、に向くよう配置されており、ゴム風船１２ｄが強く押しつけられれば、ゴム風船１２ｄを割ることができる。よって、先端根固め部を形成する時や掘削ロッド１２を引き抜く時には、掘削ロッド１２を上方移動させ、突起８１でゴム風船１２ｄを割れば良い。掘削ロッド１２を鋼管杭８の内部に配置すると、図２（ｂ）に示すように、ゴム風船１２ｄは鋼管杭８の下端部を閉塞する構造となる。   FIG. 2B shows an example in which a rubber balloon 12d is attached to the tip of the excavation rod 12 and slightly above the excavation bit 12a. In the case of this example, a protrusion 81 is also provided on the inner peripheral surface of the steel pipe pile slightly above the rubber balloon 12d. The rubber balloon 12d has a donut shape having an outer diameter substantially the same as the inner diameter of the steel pipe pile 8, and the central hollow portion is fixed to the excavation rod 12d. The rubber balloon 12d prevents the soil cement 5 from entering the inside from the tip of the steel pipe pile 8, and allows the excavating rod 12 to move in the vertical direction. On the other hand, the protrusion 81 on the inner periphery of the steel pipe pile 8 is arranged so that the sharp part is directed downward, that is, in the direction of the rubber balloon 12d. If the rubber balloon 12d is strongly pressed, the rubber balloon 12d may be broken. it can. Therefore, when forming the tip rooting portion or pulling out the excavation rod 12, the excavation rod 12 may be moved upward and the rubber balloon 12 d may be broken by the protrusion 81. When the excavation rod 12 is disposed inside the steel pipe pile 8, the rubber balloon 12d has a structure that closes the lower end portion of the steel pipe pile 8 as shown in FIG.

この他、図２（ｂ）に示した機構の他の例として、突起８１を設けずに、掘削ロッド１２を介して空気を送ったり抜いたりして、施工状況に応じ膨張収縮させるとしても良い。   In addition, as another example of the mechanism shown in FIG. 2 (b), air may be sent or removed through the excavating rod 12 without providing the protrusion 81, and may be expanded and contracted according to the construction situation. .

（ｂ）施工方法の例：第２の実施の形態
第１の実施の形態の別の例を、第２の実施の形態として説明する。第２の実施の形態では、上記（ａ）の工程（２）において支持層の手前までの掘削とし、上記（ａ）の工程（６）にて支持層まで掘削を行う。図３は、本実施の形態に係る施工手順を、模式的に示す断面図である。図３（１）から図３（７）までの番号順が、施工の順番を示しており、この番号に沿って、第２の実施の形態を説明する。また、第１の実施の形態と同じものについては、同じ符号を付し、詳細な説明は省略する。また、掘削ロッド１２の鋼管杭８の先端を閉塞させる機構は、第１の実施の形態と同様である。さらに、本実施の形態で使用する掘削ロッド１２は、掘削ビット１２ａに、鋼管杭８の外径よりも大きい直径の掘削穴２を作れかつ鋼管杭８の内部が通過できるように、拡翼機能を備えている。 (B) Example of construction method: second embodiment Another example of the first embodiment will be described as a second embodiment. In the second embodiment, excavation is performed up to the front of the support layer in step (2) of (a), and excavation is performed up to the support layer in step (6) of (a). FIG. 3 is a cross-sectional view schematically showing a construction procedure according to the present embodiment. The order of numbers from FIG. 3 (1) to FIG. 3 (7) indicates the order of construction, and the second embodiment will be described along these numbers. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The mechanism for closing the tip of the steel pipe pile 8 of the excavation rod 12 is the same as that in the first embodiment. Furthermore, the excavation rod 12 used in the present embodiment has a blade expanding function so that the excavation bit 2 can be formed with an excavation hole 2 having a diameter larger than the outer diameter of the steel pipe pile 8 and the inside of the steel pipe pile 8 can pass therethrough. It has.

（１）から（５）までは、上記（ａ）の工程（１）から工程（５）までと、同一内容の施工を行う。但し、（ａ）の工程（２）における「支持層まで」は、「支持層手前まで」に読み替える。   From (1) to (5), the same construction as in steps (1) to (5) of (a) above is performed. However, “up to the support layer” in step (2) of (a) is read as “up to the front of the support layer”.

（６）鋼管杭８を支持層の手前まで建て込めば、掘削穴２の下部にあったソイルセメント５により、鋼管杭８の外周部のほぼ全長をソイルセメント５で満たした状態となる。この状態で、鋼管杭８の先端部の閉塞を解くと共に、掘削ビット１２ａを拡翼して富配合のセメントミルクを注入しながら掘削を開始する。所定深度まで掘削を行ったら、掘削ロッド１２を回転させながら所定ストロークだけ上下動させて、注入した富配合のセメントミルクと新たに掘削した土砂とを攪拌混合して、先端根固め用の富配合ソイルセメント６を造成する。この時、掘削ロッド１２と同時に鋼管杭８も上下動や回転させてもよい。また、支持層掘削を拡翼せずに行い、所定深度まで掘削した後、掘削ビット１２ａを拡翼して先端根固め用の富配合ソイルセメント６を造成してもよい。   (6) If the steel pipe pile 8 is built up to the front of the support layer, the soil cement 5 at the bottom of the excavation hole 2 fills the entire length of the outer periphery of the steel pipe pile 8 with the soil cement 5. In this state, the end of the steel pipe pile 8 is unblocked, and the excavation bit 12a is expanded to start excavation while injecting rich blended cement milk. After excavation to a predetermined depth, the excavation rod 12 is rotated and moved up and down by a predetermined stroke, and the injected rich blended cement milk and the newly excavated soil are mixed and mixed to enrich the tip. Soil cement 6 is created. At this time, the steel pipe pile 8 may be moved up and down or rotated simultaneously with the excavation rod 12. Alternatively, the support layer excavation may be performed without expanding the blades, and after excavating to a predetermined depth, the excavation bit 12a may be expanded to form the rich blended soil cement 6 for tip consolidation.

（７）先端根固め用の富配合ソイルセメント６が造成できたら、掘削ロッド１２を引き抜き、さらに、鋼管杭８を、自重沈設および回転圧入によって、富配合ソイルセメント６の中まで建て込む。この時、鋼管杭８の上端部は、地面よりも下面に配置される場合があっても構わない。その後、ソイルセメント５と富配合ソイルセメント６を固化させる。   (7) When the rich blended soil cement 6 for root consolidation is formed, the excavation rod 12 is pulled out, and the steel pipe pile 8 is built into the rich blended soil cement 6 by its own weight settling and rotary press-fitting. At this time, the upper end portion of the steel pipe pile 8 may be disposed on the lower surface of the ground. Thereafter, the soil cement 5 and the rich blended soil cement 6 are solidified.

本実施の形態によれば、第１の実施の形態の効果の他に、富配合ソイルセメント６が、地盤３の土砂と富配合のセメントミルクとを攪拌して造成されるので、ソイルセメント５との混合が発生せず、富配合ソイルセメント６の品質を、より厳密に管理することが可能となる。この為、鋼管杭８の支持力に大きな影響を与える先端根固め部の品質を重要視する場合は、本実施の形態は有用である。   According to the present embodiment, in addition to the effects of the first embodiment, the rich blended soil cement 6 is formed by stirring the earth and sand of the ground 3 and the rich blended cement milk. And the quality of the rich blended soil cement 6 can be controlled more strictly. For this reason, this embodiment is useful when importance is attached to the quality of the distal end solidified portion that greatly affects the supporting force of the steel pipe pile 8.

（ｃ）施工方法の例：第３の実施の形態
第１の実施の形態の別の例を、第３の実施の形態として説明する。第３の実施の形態では、上記（ａ）の工程（４）で先端根固め用の富配合ソイルセメント６まで造成する。図４は、本実施の形態に係る施工手順を、模式的に示す断面図である。図４（１）から図４（６）までの番号順が、施工の順番を示しており、この番号に沿って、第３の実施の形態を説明する。また、第１の実施の形態と同じものについては、同じ符号を付し、詳細な説明は省略する。また、掘削ロッド１２の鋼管杭８の先端を閉塞させる機構は、第１の実施の形態と同様である
（１）から（３）までは、上記（ａ）の工程（１）から工程（３）までと、同一内容の施工を行う。 (C) Example of construction method: third embodiment Another example of the first embodiment will be described as a third embodiment. In the third embodiment, up to the rich blended soil cement 6 for solidifying the tip is formed in the step (4) of the above (a). FIG. 4 is a cross-sectional view schematically showing a construction procedure according to the present embodiment. The order of numbers from FIG. 4 (1) to FIG. 4 (6) indicates the order of construction, and the third embodiment will be described along these numbers. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Moreover, the mechanism which closes the front-end | tip of the steel pipe pile 8 of the excavation rod 12 is the same as that of 1st Embodiment. From (1) to (3), the process (1) to the process (3) of said (a). ) And the same construction as before.

（４）掘削とソイルセメント５の造成が完了したら、掘削穴２の下端部に富配合のセメントミルクを注入する。そして、掘削ロッド１１を回転させながら所定ストロークだけ上下動させて、注入した富配合のセメントミルクとソイルセメント５とを攪拌混合して、先端根固め用の富配合ソイルセメント６を造成する。富配合ソイルセメント６の造成が完了したら、掘削ロッド１１を引き抜く。ソイルセメント５の表面Aを境に、掘削穴２の上部は泥土４、掘削穴２の下部はソイルセメント５で満たされると共に、富配合ソイルセメント６の表面Bより掘削穴２の下端部は富配合ソイルセメント６で満たされる。   (4) When excavation and creation of the soil cement 5 are completed, rich blended cement milk is injected into the lower end of the excavation hole 2. Then, the excavating rod 11 is rotated up and down by a predetermined stroke, and the injected rich blended cement milk and the soil cement 5 are stirred and mixed to form a rich blended soil cement 6 for root hardening. When the formation of the rich blended soil cement 6 is completed, the excavation rod 11 is pulled out. With the surface A of the soil cement 5 as a boundary, the upper part of the excavation hole 2 is filled with mud 4 and the lower part of the excavation hole 2 is filled with the soil cement 5, and the lower end of the excavation hole 2 is richer than the surface B of the rich blended soil cement 6 Filled with compounded soil cement 6.

（５）上記泥土４とソイルセメント５の中に、自重沈設および回転圧入によって、掘削ロッド１２と共に鋼管杭８を富配合ソイルセメントの表面Bの深さまで建て込む。この時、掘削ロッド１２の先端部に備えられた、鋼管杭８の下端部を閉塞する機構により、鋼管杭８の下端部は閉塞している。この鋼管杭８の閉塞した下端部により、鋼管杭８の沈設の際にソイルセメント５の表面Aに対し、鉛直方向下向きの圧力をかけることができる。その圧力により、掘削穴２の下部にあるソイルセメント５は、鋼管杭８の下端と富配合ソイルセメント６の表面Bとの隙間から、鋼管杭８の外周部へ押し上げられる。さらに、鋼管杭８の外周部の上部にある泥土４を上方に押し上げ、鋼管杭８の外周部はそのほぼ全長がソイルセメント５で満たされる。   (5) In the mud 4 and the soil cement 5, the steel pipe pile 8 is built to the depth of the surface B of the rich blended soil cement together with the excavating rod 12 by self-weight settling and rotary press-fitting. At this time, the lower end portion of the steel pipe pile 8 is closed by a mechanism provided at the distal end portion of the excavation rod 12 to close the lower end portion of the steel pipe pile 8. Due to the closed lower end portion of the steel pipe pile 8, a vertical downward pressure can be applied to the surface A of the soil cement 5 when the steel pipe pile 8 is set. By the pressure, the soil cement 5 at the lower part of the excavation hole 2 is pushed up to the outer peripheral portion of the steel pipe pile 8 from the gap between the lower end of the steel pipe pile 8 and the surface B of the rich blended soil cement 6. Furthermore, the mud 4 at the upper part of the outer peripheral part of the steel pipe pile 8 is pushed upward, and the outer peripheral part of the steel pipe pile 8 is almost filled with the soil cement 5.

（６）鋼管杭８の外周部はそのほぼ全長がソイルセメント５で満たされた状態で、鋼管杭８の先端部の閉塞を解くと共に、掘削ロッド１２を引き抜く。引き抜いた後、鋼管杭８を所定の深さまで建て込む。すると、鋼管杭８の下端部の内部に、富配合ソイルセメント６のみが入り込む。このまま、ソイルセメント５と富配合ソイルセメント６を固化させる。   (6) The outer peripheral portion of the steel pipe pile 8 is filled with the soil cement 5 and the blockage of the tip portion of the steel pipe pile 8 is released and the excavation rod 12 is pulled out. After drawing out, the steel pipe pile 8 is built to a predetermined depth. Then, only the rich blended soil cement 6 enters the lower end of the steel pipe pile 8. In this state, the soil cement 5 and the rich blended soil cement 6 are solidified.

本実施の形態によれば、第１の実施の形態の効果の他に、セメントミルクと富配合セメントミルクの注入工程を掘削ロッド１１を引き抜かずに行えるので、施工速度を上げることができる。また、掘削ロッド１２は鋼管杭８の下端部を閉塞する機構のみで、掘削機構や拡翼機能を必要としないため、蓋１２ｂ等の鋼管杭８の下端部閉塞機構の取り付けが容易となる。   According to the present embodiment, in addition to the effects of the first embodiment, the cement milk and the rich blended cement milk can be injected without pulling out the excavating rod 11, so that the construction speed can be increased. Moreover, since the excavation rod 12 is only a mechanism for closing the lower end portion of the steel pipe pile 8 and does not require an excavation mechanism or a blade expansion function, it is easy to attach the lower end portion closing mechanism of the steel pipe pile 8 such as the lid 12b.

（ｄ）施工方法の例：第４の実施の形態
第１の実施の形態の別の例を、第４の実施の形態として説明する。第４の実施の形態では、上記（ａ）の工程（４）で先端根固め用の富配合ソイルセメント６まで造成すると共に、上記（ａ）の工程（５）で先端部を閉塞した鋼管杭８のみを建て込む。図５は、本実施の形態に係る施工手順を、模式的に示す断面図である。図５（１）から図５（６）までの番号順が、施工の順番を示しており、この番号に沿って、第４の実施の形態を説明する。また、第１の実施の形態と同じものについては、同じ符号を付し、詳細な説明は省略する。 (D) Example of construction method: fourth embodiment Another example of the first embodiment will be described as a fourth embodiment. In the fourth embodiment, the steel pipe pile which has been formed up to the rich blended soil cement 6 for tip consolidation in the step (4) of the above (a) and whose tip is closed in the step (5) of the above (a). Build only 8. FIG. 5 is a cross-sectional view schematically showing a construction procedure according to the present embodiment. The order of numbers from FIG. 5 (1) to FIG. 5 (6) indicates the order of construction, and the fourth embodiment will be described along these numbers. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

（１）から（３）までは、上記（ａ）の工程（１）から工程（３）までと、同一内容の施工を行う。   From (1) to (3), the same construction is performed as in steps (1) to (3) of (a) above.

（４）掘削とソイルセメント５の造成が完了したら、掘削穴２の下端部に富配合のセメントミルクを注入する。そして、掘削ロッド１１を回転させながら所定ストロークだけ上下動させて、注入した富配合のセメントミルクとソイルセメント５とを攪拌混合して、先端根固め用の富配合ソイルセメント６を造成する。富配合ソイルセメント６の造成が完了したら、掘削ロッド１１を引き抜く。ソイルセメント５の表面Aを境に、掘削穴２の上部は泥土４、掘削穴２の下部はソイルセメント５で満たされると共に、富配合ソイルセメント６の表面Bより掘削穴２の下端部は富配合ソイルセメント６で満たされる。   (4) When excavation and creation of the soil cement 5 are completed, rich blended cement milk is injected into the lower end of the excavation hole 2. Then, the excavating rod 11 is rotated up and down by a predetermined stroke, and the injected rich blended cement milk and the soil cement 5 are stirred and mixed to form a rich blended soil cement 6 for root hardening. When the formation of the rich blended soil cement 6 is completed, the excavation rod 11 is pulled out. With the surface A of the soil cement 5 as a boundary, the upper part of the excavation hole 2 is filled with mud 4 and the lower part of the excavation hole 2 is filled with the soil cement 5, and the lower end of the excavation hole 2 is richer than the surface B of the rich blended soil cement 6 Filled with compounded soil cement 6.

（５）上記泥土４とソイルセメント５の中に、自重沈設および回転圧入によって、下端部が閉塞した鋼管杭８を富配合ソイルセメントの表面Bの深さまで建て込む。この時、鋼管杭８の閉塞された下端部により、鋼管杭８の建て込みの際にソイルセメント５の表面Aに対し、鉛直方向下向きの圧力をかけることができる。その圧力により、掘削穴２の下部にあるソイルセメント５は、鋼管杭８の下端と富配合ソイルセメント６の表面Bとの隙間から、鋼管杭８の外周部へ押し上げられる。さらに、鋼管杭８の外周部の上部にある泥土４を上方に押し上げ、鋼管杭８の外周部はそのほぼ全長がソイルセメント５で満たされる。   (5) In the mud 4 and the soil cement 5, the steel pipe pile 8 whose lower end is closed is built up to the depth of the surface B of the rich blended soil cement by its own weight settling and rotary press-fitting. At this time, by the closed lower end portion of the steel pipe pile 8, it is possible to apply vertical downward pressure to the surface A of the soil cement 5 when the steel pipe pile 8 is built. By the pressure, the soil cement 5 at the lower part of the excavation hole 2 is pushed up to the outer peripheral portion of the steel pipe pile 8 from the gap between the lower end of the steel pipe pile 8 and the surface B of the rich blended soil cement 6. Furthermore, the mud 4 at the upper part of the outer peripheral part of the steel pipe pile 8 is pushed upward, and the outer peripheral part of the steel pipe pile 8 is almost filled with the soil cement 5.

（６）鋼管杭８の外周部はそのほぼ全長がソイルセメント５で満たされた状態で、さらに、鋼管杭８を所定の深さまで建て込む。すると、この鋼管杭８の閉塞された下端部により、鋼管杭８の建て込みの際に富配合ソイルセメント６の表面Bに対し、鉛直方向下向きの圧力をかけることができる。その圧力により、掘削穴２の下端部にある富配合ソイルセメント６は、鋼管杭８の下端部と掘削穴２の底との隙間から、鋼管杭８の外周部へ押し上げられる。さらに、鋼管杭８の外周部の上部にあるソイルセメント５を上方に押し上げ、鋼管杭８の外周部は、ほぼ全長がソイルセメント５と富配合ソイルセメント６で満たされる。その後、ソイルセメント５と富配合ソイルセメント６を固化させる。   (6) The outer peripheral portion of the steel pipe pile 8 is further filled with the soil cement 5 and the steel pipe pile 8 is further built to a predetermined depth. Then, by the closed lower end portion of the steel pipe pile 8, a downward pressure in the vertical direction can be applied to the surface B of the rich blended soil cement 6 when the steel pipe pile 8 is built. Due to the pressure, the rich blended soil cement 6 at the lower end portion of the excavation hole 2 is pushed up to the outer peripheral portion of the steel pipe pile 8 from the gap between the lower end portion of the steel pipe pile 8 and the bottom of the excavation hole 2. Furthermore, the soil cement 5 at the upper part of the outer peripheral portion of the steel pipe pile 8 is pushed upward, and the outer peripheral portion of the steel pipe pile 8 is almost filled with the soil cement 5 and the rich blended soil cement 6. Thereafter, the soil cement 5 and the rich blended soil cement 6 are solidified.

なお、第４の実施の形態において、鋼管杭８の先端部を閉塞する構造は、特に制限はないが、例えば、鋼管杭８の先端に鋼板等を溶接し完全に覆う、鋼管杭８の先端部の内周面に、鋼板等を溶接して閉塞する、等が、ソイルセメント５、富配合ソイルセメント６もしくは水７６から受ける圧力に耐えられる構造として考えられる。また、鋼管杭８の下端部を錐体状に形成して、ソイルセメント５等を当該錐体状下端部の側面に沿って移動させ、より沈設しやすくしても良い。また、浮力により鋼管杭８が浮いてこないように、鋼管杭８の内部に沈下調整用の水７６等を入れておくのが好ましい。   In addition, in 4th Embodiment, the structure which obstruct | occludes the front-end | tip part of the steel pipe pile 8 does not have a restriction | limiting in particular, For example, the front-end | tip of the steel pipe pile 8 which welds a steel plate etc. to the front-end | tip of the steel pipe pile 8, and completely covers It can be considered as a structure that can withstand the pressure received from the soil cement 5, the rich blended soil cement 6, or the water 76, such as welding and closing a steel plate or the like on the inner peripheral surface of the portion. Moreover, the lower end part of the steel pipe pile 8 may be formed in a cone shape, and the soil cement 5 or the like may be moved along the side surface of the cone-like lower end part so that the steel pipe pile 8 can be easily laid. Moreover, it is preferable to put water 76 for subsidence adjustment in the steel pipe pile 8 so that the steel pipe pile 8 does not float due to buoyancy.

本実施の形態によれば、第１の実施の形態の効果の他に、掘削ロッド１２の引抜きの手間が省けるので、施工時間をさらに短くすることができる。浮力との関係を考慮すると、比較的短い鋼管杭に好適である。   According to the present embodiment, in addition to the effects of the first embodiment, the labor for pulling out the excavation rod 12 can be saved, so that the construction time can be further shortened. Considering the relationship with buoyancy, it is suitable for relatively short steel pipe piles.

なお、第１から第４の実施の形態においては、説明の簡略化の為、鋼管杭８が１本の場合で説明したが、鋼管杭８が複数本連結された場合でも同様の効果を奏する。   In the first to fourth embodiments, for the sake of simplification, the description has been given in the case of one steel pipe pile 8. However, the same effect can be obtained even when a plurality of steel pipe piles 8 are connected. .

なお、第１から第４の実施の形態においては、既製杭として鋼管杭８にて説明したが、本発明はこれに限定されない。既製杭は、通常用いられている既製杭であれば良く、鋼管製でもコンクリート製でも、もしくは鋼管とコンクリートのハイブリット製でも使用可能である。   In addition, in the 1st to 4th embodiment, although the steel pipe pile 8 demonstrated as a ready-made pile, this invention is not limited to this. The ready-made pile may be a ready-made pile that is usually used, and may be made of steel pipe, concrete, or a hybrid of steel pipe and concrete.

なお、第１から第４の実施の形態においては、掘削穴２にセメントミルクを注入した際に泥土４が多少はあふれる為、必要に応じて、上記（１）の前に、先行掘削して、あふれる分の土砂を除いておいても良い。   In the first to fourth embodiments, when the cement milk is poured into the excavation hole 2, the mud 4 overflows somewhat. Therefore, if necessary, prior excavation is performed before (1). You can remove the overflowing earth and sand.

なお、第１から第４の実施の形態においては、掘削液として水を用いたが、本発明はこれに限定されない。掘削液として、泥水やベントナイト泥水等、既製杭の施工に一般的に使用されるものを用いても良い。さらに、掘削液を用いて地盤を泥土化する代わりに、空気を吹き込んで地盤を軟化させても良い。施工仕様や使用する既製杭に合わせて、適宜選択すれば良いが、ソイルセメント５および富配合ソイルセメント６の性能を十分に引き出す為と排土量を減らす為には、掘削液を用いるのが望ましく、特に水を用いるのが最も望ましい。   In the first to fourth embodiments, water is used as the drilling fluid, but the present invention is not limited to this. As the drilling fluid, one that is generally used for construction of ready-made piles such as mud and bentonite mud may be used. Furthermore, instead of mudging the ground using the drilling fluid, air may be blown to soften the ground. Depending on the construction specifications and ready-made piles to be used, it may be selected as appropriate, but in order to fully extract the performance of the soil cement 5 and the rich blended soil cement 6 and to reduce the amount of soil discharged, it is necessary to use a drilling fluid. Desirable, and most preferably using water.

なお、第１から第４の実施の形態において、先端根固め部を形成したが、本発明はこれに限定されない。支持層の状態、鋼管杭８の杭径もしくは鋼管杭８の長さによっては、先端根固め部を設けなくても良い。また、第１から第４の実施の形態において、先端根固め部における穴径を掘削穴２の中央部の穴径と同じとしたが、本発明はこれに限定されない。先端根固め部を拡翼可能な拡翼機能を有する掘削ビットで掘削し、先端根固め部の穴径を掘削穴２の中央部の穴径より大きくしても良い。具体的には、例えば、図１（６）、図３（６）、図４（４）および図５（４）に示した富配合ソイルセメント６からなる先端根固め部を形成する際に、この拡翼機能付きの掘削ビットを使用して施工する。勿論、掘削穴２の全長を、当該拡翼機能付きの掘削ビットを使用し、必要とする穴径に合わせて拡翼の要否を選択しながら掘削しても良い。   In the first to fourth embodiments, the tip rooting portion is formed, but the present invention is not limited to this. Depending on the state of the support layer, the pile diameter of the steel pipe pile 8 or the length of the steel pipe pile 8, it is not necessary to provide the tip root-setting part. Further, in the first to fourth embodiments, the hole diameter in the tip rooting portion is the same as the hole diameter in the central portion of the excavation hole 2, but the present invention is not limited to this. It is also possible to excavate with a drill bit having a blade expansion function capable of expanding the tip root consolidation portion, and to make the diameter of the tip consolidation portion larger than the diameter of the central portion of the excavation hole 2. Specifically, for example, when forming the root solidified portion made of the rich blended soil cement 6 shown in FIGS. 1 (6), 3 (6), 4 (4) and 5 (4), Construction is performed using this excavation bit with a blade expansion function. Of course, the entire length of the excavation hole 2 may be excavated by using the excavation bit with the blade expansion function and selecting whether or not the blade expansion is necessary according to the required hole diameter.

なお、第１から第４の実施の形態において、鋼管杭８の下端部の外周面には、先端根固め部における支持力を向上させる為の突起を複数段設けても良い。   In the first to fourth embodiments, the outer peripheral surface of the lower end portion of the steel pipe pile 8 may be provided with a plurality of protrusions for improving the supporting force at the tip rooting portion.

本発明に係る既製杭の施工方法の第１の実施の形態を模式的に説明する断面図である。It is sectional drawing which illustrates typically 1st Embodiment of the construction method of the ready-made pile which concerns on this invention. 掘削ロッド１２の先端部に備えられた、鋼管杭８の下端部を閉塞する機構を、模式的に説明する断面図である。It is sectional drawing explaining typically the mechanism with which the front-end | tip part of the excavation rod 12 was closed | closed at the lower end part of the steel pipe pile 8. FIG. 本発明に係る既製杭の施工方法の第２の実施の形態を模式的に説明する断面図である。It is sectional drawing which illustrates typically 2nd Embodiment of the construction method of the ready-made pile which concerns on this invention. 本発明に係る既製杭の施工方法の第３の実施の形態を模式的に説明する断面図である。It is sectional drawing which illustrates typically 3rd Embodiment of the construction method of the ready-made pile which concerns on this invention. 本発明に係る既製杭の施工方法の第４の実施の形態を模式的に説明する断面図である。It is sectional drawing which illustrates typically 4th Embodiment of the construction method of the ready-made pile which concerns on this invention.

符号の説明Explanation of symbols

１１ 掘削ロッド
１２ 掘削ロッド（鋼管杭８の先端部を閉塞する機構付）
１２ａ 掘削ビット
１２ｂ 蓋
１２ｃ ゴムパッキン
１２ｄ ゴム風船
２ 掘削穴
３ 地盤
４ 泥土
５ ソイルセメント
６ 富配合ソイルセメント
７６ 水
８ 鋼管杭
８１ 突起 11 Excavation rod 12 Excavation rod (with mechanism to close the tip of steel pipe pile 8)
12a Drilling Bit 12b Lid 12c Rubber Packing 12d Rubber Balloon 2 Drilling Hole 3 Ground 4 Mud 5 Soil Cement 6 Wealed Soil Cement 76 Water 8 Steel Pipe Pile 81 Projection

Claims (2)

既製杭を建て込む地盤を掘削した後、掘削された地盤中に固化材を注入し、前記注入された固化材と土砂とを攪拌して改良体を造成し、さらに、前記造成された改良体に下端部が閉塞した既製杭を建て込むことを特徴とする既製杭の施工方法。   After excavating the ground into which the ready-made piles are built, the solidified material is injected into the excavated ground, and the injected solidified material and the earth and sand are stirred to form an improved body, and further, the formed improved body The construction method of the ready-made pile characterized by installing the ready-made pile with which the lower end part was obstruct | occluded in the inside. 既製杭を建て込む地盤を掘削した後、掘削された地盤中に固化材を注入し、前記注入された固化材と土砂とを攪拌して改良体を造成し、さらに、前記造成された改良体に、鋼管杭の内部に配置された掘削ロッドにより下端部が閉塞した既製杭を建て込むことを特徴とする既製杭の施工方法。   After excavating the ground into which the ready-made piles are built, the solidified material is injected into the excavated ground, and the injected solidified material and the earth and sand are stirred to form an improved body, and further, the formed improved body The construction method of the ready-made pile characterized by installing the ready-made pile which the lower end part obstruct | occluded by the excavation rod arrange | positioned inside the steel pipe pile.
JP2006255692A 2006-09-21 2006-09-21 Construction method of ready-made piles Expired - Fee Related JP4872561B2 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013204404A (en) * 2012-03-29 2013-10-07 Kajima Corp Construction method of steel pipe pile
KR20160095587A (en) 2015-02-03 2016-08-11 강상욱 Digging device for foundation pile and method for reinforcing soil using thereof
JP2017002498A (en) * 2015-06-05 2017-01-05 システム計測株式会社 Tip shoe of pile and pile structure
CN115262543A (en) * 2022-08-19 2022-11-01 中建港航局集团有限公司 Composite pile construction auxiliary device

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JP2002047647A (en) * 2000-08-03 2002-02-15 Nkk Corp Steel pipe pile and executing method therefor
JP2002201638A (en) * 2000-12-28 2002-07-19 Asahi Kasei Corp Soil-cement composite pile and construction method thereof
JP2005009240A (en) * 2003-06-20 2005-01-13 Geotop Corp Method for installing soil hardened matter on-site-manufactured pile and prefabricated pile

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002047647A (en) * 2000-08-03 2002-02-15 Nkk Corp Steel pipe pile and executing method therefor
JP2002201638A (en) * 2000-12-28 2002-07-19 Asahi Kasei Corp Soil-cement composite pile and construction method thereof
JP2005009240A (en) * 2003-06-20 2005-01-13 Geotop Corp Method for installing soil hardened matter on-site-manufactured pile and prefabricated pile

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013204404A (en) * 2012-03-29 2013-10-07 Kajima Corp Construction method of steel pipe pile
KR20160095587A (en) 2015-02-03 2016-08-11 강상욱 Digging device for foundation pile and method for reinforcing soil using thereof
JP2017002498A (en) * 2015-06-05 2017-01-05 システム計測株式会社 Tip shoe of pile and pile structure
CN115262543A (en) * 2022-08-19 2022-11-01 中建港航局集团有限公司 Composite pile construction auxiliary device

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