JP2004116020A

JP2004116020A - Removal method and drawing device for existing pile

Info

Publication number: JP2004116020A
Application number: JP2002276905A
Authority: JP
Inventors: Tadayoshi Ishibashi; 石橋　忠良; Haruo Sato; 佐藤　春雄; Shoichi Furuyama; 古山　章一; Yutaka Sato; 佐藤　豊
Original assignee: East Japan Railway Co
Current assignee: East Japan Railway Co
Priority date: 2002-09-24
Filing date: 2002-09-24
Publication date: 2004-04-15
Anticipated expiration: 2022-09-24
Also published as: JP3658582B2

Abstract

PROBLEM TO BE SOLVED: To provide a removal method capable of reducing a labor cost and expenses necessary for removal of existing piles when a portion to be removed in the existing pile is a part of the longitudinal direction of the existing pile, in particular when the portion to be removed is lower than the ground surface and a drawing device for the existing pile favorably usable for the removing method. SOLUTION: The existing pile 1 is cut in the cross sectional direction at the position 1Rb of the lower end of the portion 1R to be removed and divided into a drawing part 11 and a leaving part 12. The drawing part 11 is moved by a required height h1 upward of the ground G. COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、既設杭の撤去方法及び引上装置に係り、特に、既設杭の長さ方向の一部を撤去する既設杭の撤去方法及び引上装置に関する。
【０００２】
【従来の技術】
地盤中にシールド工法によりトンネルを構築する場合、都市部などにおいては、シールドの通過予定路線途上に既設杭が埋まったまま残されている場合がある。この場合、シールドを通過させる前に、この既設杭を撤去しておく必要がある。
【０００３】
既設杭の撤去方法としては、既設杭の側周の地盤を掘削して空中に露出させ撤去する方法や、既設杭より径の大きい鋼管等のケーシングを既設杭と同心となるように地盤中に埋設し、このケーシングを引き上げることにより、ケーシングと既設杭との間の土砂による摩擦抵抗を利用して既設杭をケーシングと一体に引き上げる方法、ケーシング内に水やベントナイト等を加えケーシング内の土砂を泥濘化することによって既設杭の引き上げの際の摩擦抵抗を軽減し、既設杭のみを引き上げる方法などがある。
この種の技術は、例えば特許文献１などに開示されている。
【０００４】
これら各方法では、地盤中に埋没している既設杭の長さが長い場合、地盤の掘削深さや、ケーシングの打ち込み深さが長くなり、多大な労力や費用を要し、工期も長びく。
また、上記のようにシールドの通過予定路線途上の既設杭を撤去する場合、必ずしも既設杭全体を撤去する必要はなく、既設杭のうち、シールドの通過予定位置と干渉する部分のみを撤去すればよい。
【０００５】
【特許文献１】
特開平６−４１９６０号公報（図１〜図３）
【０００６】
【発明が解決しようとする課題】
本発明の課題は、既設杭の撤去すべき部位が、既存杭の長さ方向途上の一部である場合、特に、この撤去すべき部位が地盤の表面より下方に位置する場合に、この既設杭の撤去に要する労力や費用を軽減できる、既設杭の撤去方法、及びこの既設杭の撤去方法に好適に使用できる既設杭の引上装置を提供することである。
【０００７】
【課題を解決するための手段】
以上の課題を解決するため、請求項１に記載の発明は、例えば図１、図３に示すように、既設杭１，２の長さ方向の少なくとも一部を上方に移動して撤去する既設杭の撤去方法であって、
前記既設杭１，２を、その撤去すべき部位１Ｒ，２Ｒの下端の位置１Ｒｂ，２Ｒｂで横断方向に切断してこの既設杭１，２を引抜部１１，２１と残置部１２，２２とに分断し、前記引抜部１１，２１を地盤Ｇの上方へ所望の高さｈ１，ｈ２だけ移動させること
を特徴とする。
ここで、既設杭を引抜部と残置部とに分断するには、例えば、図１（ｂ）に示すように、既存杭１の内部に穿設された貫通孔１Ｈに挿入したカッタ（図示せず）や、図３（ｄ）に示すように、既存杭２とその側周を取り巻くケーシング７１との間の空隙に挿入したワイヤソー８２などによって、既存杭をその撤去すべき部位の下端の位置で切断するなどの方法を採る。
【０００８】
請求項１に記載の発明によれば、既設杭を、その撤去すべき部位の下端の位置で横断方向に切断してこの既設杭を引抜部と残置部とに分断し、引抜部を地盤の上方へ所望の高さだけ移動させるので、既存杭の撤去すべき部位以外の部位を地盤中に残して、撤去すべき部位のみを撤去することができる。
また、既設杭のうち引抜部のみを上方へ移動させるので、この引抜部を上方へ移動させるのに必要な力やエネルギーが、既設杭全体を上方へ移動させる場合よりも小さくて済む。したがって、比較的径が大きい場所打ちコンクリート杭の撤去を簡便に行える。
特に、この撤去すべき部位が、既存杭の長さ方向途上の一部であって、かつ地盤の表面より下方に位置する場合、既存杭の撤去すべき部位とこれより上方の部位をともに撤去する場合よりも、既存杭を上方へ移動させるのに必要な力やエネルギーが小さくて済み、既存杭を撤去するための労力や費用を大幅に軽減できる。
【０００９】
請求項２に記載の発明は、例えば図１、図４に示すように、請求項１に記載の既設杭の撤去方法において、
前記引抜部１１，２１を所定長ｐ１，ｐ２だけ地盤Ｇの上方へ移動させ、引抜部１１，２１をその上端１１ｔ，２１ｔより前記所定長ｐ１，ｐ２だけ下方の位置１１ａ，２１ａで横断方向に切断して短縮することを繰り返して、前記引抜部１１，２１を地盤Ｇの上方へ移動させること
を特徴とする。
【００１０】
請求項２に記載の発明によれば、請求項１に記載の発明と同様の効果が得られるとともに、引抜部を所定長だけ地盤の上方へ移動させ、引抜部をその上端よりこの所定長だけ下方の位置で横断方向に切断して短縮することを繰り返して、引抜部を地盤の上方へ移動させるので、引抜部を上方へ移動させる機械のストロークが短くて済む。
したがって、既設杭の上方の空間に制約があるような狭隘な箇所でも、既設杭の撤去すべき部位の撤去を行いやすい。
【００１１】
請求項３に記載の発明は、例えば図４〜図７に示すように、請求項１又は２に記載の既設杭の撤去方法において、
前記引抜部２１をその縦断方向に切断して複数の引抜ブロック２１Ａ〜２１Ｈに分割し、各引抜ブロック２１Ａ〜２１Ｈを順次地盤Ｇの上方へ移動させることを特徴とする。
【００１２】
請求項３に記載の発明によれば、請求項１又は２に記載の発明と同様の効果が得られるとともに、引抜部をその縦断方向に切断して複数の引抜ブロックに分割するが、各引抜ブロックの重量やこれと周面の地盤との摩擦力は、引抜部全体の重量やこれと周面の地盤との摩擦力に対して、およそ上記分割数分の１である。つまり、これら引抜ブロックを順次地盤Ｇの上方へ移動させるのに必要な力は、引抜部全体を同時に地盤の上方へ移動させるのに必要な力に対して、およそ上記分割数分の１である。そして、各引抜ブロックを順次地盤の上方へ移動させるので、これら引抜ブロックの移動を行う機械（引上装置）は、引抜ブロックのうち一つを上方に移動させることができる出力を備えていれば良く、引抜部全体を同時に上方へ移動させる場合に比べて小型の機械を用いて、引抜部を地盤の上方へ移動させることができる。
この効果は、比較的径が大きい場所打ちコンクリート杭の撤去を行う場合に、顕著に現れる。
【００１３】
請求項４に記載の発明は、例えば図１に示すように、請求項１〜３のいずれか一項に記載の既設杭の撤去方法において、
前記既設杭１の内部に、この既設杭１の上端１ｔから前記残置部１２の途中まで到達する貫通孔１Ｈを穿設し、この貫通孔にロッド３を挿入してその先端３ａを前記残置部１２内の前記貫通孔１Ｈの底面１Ｈｂに当接させ、このロッド３に反力を負担させながら前記引抜部１１を地盤Ｇの上方へ移動させること
を特徴とする。
ここで、引抜部１１を地盤Ｇの上方へ移動させると、引抜部１１と残置部１２との間に空洞が形成され、空洞の内部でロッド３が露出する。このロッド３の座屈を防ぐ観点から、例えば図１に示すように、引抜部１１を地盤Ｇの上方へ所定長移動させる毎に、この空洞に埋戻し土などの充填材４を充填することが好ましい。
【００１４】
請求項４に記載の発明によれば、請求項１〜３のいずれか一項に記載の発明と同様の効果が得られるとともに、既設杭の内部に、この既設杭の上端から前記残置部の途中まで到達する貫通孔を穿設し、この貫通孔にロッドを挿入してその先端を残置部内の貫通孔の底面に当接させ、このロッドに反力を負担させながら引抜部を地盤の上方へ移動させるので、引抜部を地盤の上方へ移動させる時に、反力を負担させるための支持面を地盤の表面の既存杭の側周部などに確保する必要がない。
したがって、既設杭の側周部に作業余地が確保できない狭隘な箇所でも、引抜部を地盤の上方へ移動させることができる。
【００１５】
請求項５に記載の発明は、例えば図４，図７に示すように、請求項３に記載の既設杭の撤去方法において、
前記引抜ブロック２１Ａ〜２１Ｈの少なくとも一つ２１Ａ，２１Ｃ，２１Ｅに反力を負担させながら他の少なくとも一つの引抜ブロック２１Ｇを地盤Ｇの上方へ移動させることを繰り返して、各引抜ブロック２１Ａ〜２１Ｈを順次地盤Ｇの上方へ移動させること
を特徴とする。
【００１６】
請求項５に記載の発明によれば、請求項３に記載の発明と同様の効果が得られるとともに、引抜ブロックの少なくとも一つに反力を負担させながら他の少なくとも一つの引抜ブロックを地盤の上方へ移動させることを繰り返して、各引抜ブロックを順次地盤の上方へ移動させるので、各引抜ブロックを引き上げる時に、反力を負担させるための支持面を地盤の表面の既存杭の側周部などに確保する必要がない。
したがって、既設杭の側周部に作業余地が確保できない狭隘な箇所でも、引抜部を地盤の上方へ移動させることができる。
【００１７】
請求項６に記載の発明は、例えば図２、図３に示すように、請求項１〜５のいずれか一項に記載の既設杭の撤去方法において、
前記引抜部１１，２１を地盤Ｇの上方へ移動させる時、この引抜部１１，２１とその側周の地盤Ｇとの間の摩擦力を絶つか又は低減させておくこと
を特徴とする。
ここで、引抜部とその側周の地盤との間の摩擦力を絶つためには、例えば図４に示すように、既設杭２の引抜部２１の側周を覆うように、地盤中にケーシング７１を挿入するなどの方法を採る。
また、引抜部とその側周の地盤との間の摩擦力を低減させるためには、例えば図２に示すように、既設杭１の引抜部１１の側周の地盤中に、滑材６２などの摩擦減少剤を注入するなどの方法を採る。
【００１８】
請求項６に記載の発明によれば、請求項１〜５のいずれか一項に記載の発明と同様の効果が得られるとともに、引抜部を地盤の上方へ移動させる時、この引抜部とその側周の地盤との間の摩擦力を絶つか又は低減させておくので、引抜部を地盤Ｇの上方に移動させる機械の出力が小さくて済み、使用するエネルギーも低減できる。
【００１９】
請求項７に記載の発明は、例えば図１，図３に示すように、請求項１〜６のいずれか一項に記載の既設杭の撤去方法において、
前記引抜部１１，２１が上方に移動することによって形成される空洞Ｖに、充填材（高流動性土）４を充填すること
を特徴とする。
【００２０】
請求項７に記載の発明によれば、請求項１〜６のいずれか一項に記載の発明と同様の効果が得られるとともに、引抜部が上方に移動することによって形成される空洞に、充填材を充填するので、地盤の上方へ移動された引抜部が、この充填材に載置されて支持される。したがって、引抜部を地盤中の一定の高さに安定させることができる。
【００２１】
請求項８に記載の発明は、請求項１〜７のいずれか一項に記載の既設杭の撤去方法において、
前記引抜部１１，２１を地盤Ｇの上方へ所望の高さｈ１，ｈ２だけ移動させた後、この引抜部１１，２１とその側周の地盤Ｇとの間の摩擦力を所定値以上にすること
を特徴とする。
ここで、引抜部とその側周の地盤との間の摩擦力を所定値以上にするには、例えば、既設杭の引抜部の側周の地盤中に、セメントミルクなどの摩擦増加剤を注入するなどの方法を採る。
また、請求項６に記載のように、引抜部を地盤の上方へ移動させる時、この引抜部とその側周の地盤との間の摩擦力を絶つか又は低減させていた場合、引抜部を地盤の上方へ移動させた後でこの引抜部とその側周の地盤との間の摩擦力を所定値以上にするには、以下のような方法を採る。
まず、図４に示すように、既設杭２の引抜部２１の側周を覆うように地盤中にケーシング７１を挿入して、引抜部２１とその側周の地盤Ｇとの間の摩擦力を絶っていた場合には、このケーシング７１を除去し、既設杭２の引抜部２１とケーシング７１との間に形成されていた空隙に例えば高流動性土を充填した後、この充填部分にセメントミルクを注入したりするなどして、引抜部２１とその側周の地盤Ｇとの間の摩擦力を所定値以上にする。
また、図２に示すように、既設杭１の引抜部１１の側周の地盤中に滑材６２などの摩擦減少剤を注入して、引抜部１１とその側周の地盤Ｇとの間の摩擦力を絶っていた場合には、この滑材６２として、時間が経過すると硬化するものを用いれば、引抜部１１を地盤Ｇの上方へ移動させた後で格別な処理をすることなく、引抜部１１とその側周の地盤Ｇとの間の摩擦力を所定値以上にできる。
【００２２】
請求項８に記載の発明によれば、請求項１〜７のいずれか一項に記載の発明と同様の効果が得られるとともに、引抜部１１，２１を地盤Ｇの上方へ所望の高さｈ１，ｈ２だけ移動させた後、この引抜部１１，２１とその側周の地盤Ｇとの間の摩擦力を所定値以上にするので、地盤Ｇの上方へ移動された引抜部１１，２１が、この摩擦力によって地盤Ｇ中の一定の高さに安定する。
【００２３】
請求項９に記載の発明は、例えば図１に示すように、請求項４に記載の既設杭の撤去方法において用いられる既設杭の引上装置５であって、
前記ロッド３を押し引き可能なロッド押引手段（ジャッキ）５１と、
前記ロッド押引手段５１に取り付けられ、このロッド押引手段５１の側方を所定間隔で取り囲む複数本の引抜部押引手段（ジャッキ）５２と、
前記各引抜部押引手段５２によって前記ロッド３と平行に押し引きされるアーム５３と、
前記各アーム５３の先端に取り付けられ、前記引抜部１１の側面を挟み込んで挟持可能な挟持手段（チャック）５３ａと
を備えることを特徴とする。
【００２４】
請求項９に記載の発明によれば、請求項４に記載の発明と同様の効果が得られる。
【００２５】
請求項１０に記載の発明は、例えば図４，図７に示すように、請求項５に記載の既設杭の撤去方法において用いられる既設杭の引上装置９であって、
前記各引抜ブロック２１Ａ〜２１Ｈを押し引き可能なブロック押引手段（ジャッキ）９１〜９４が、２本以上備えられ、
前記各ブロック押引手段９１〜９４は、それぞれに連結された前記引抜ブロック２１Ａ〜２１Ｈを、互いに独立な動作で同時に押し引き可能な状態に、互いに平行に固定されていること
を特徴とする。
【００２６】
請求項１０に記載の発明によれば、請求項５に記載の発明と同様の効果が得られる。
【００２７】
【発明の実施の形態】
以下に、本発明の既設杭の撤去方法の実施の形態を、図面を参照して説明する。
第１の実施の形態及び第２の実施の形態に記載の既設杭の撤去方法は、ともに、既設杭の長さ方向の一部を上方に移動して撤去する既設杭の撤去方法であって、図１、図３に示すように、既設杭１，２を、その撤去すべき部位１Ｒ，２Ｒの下端の位置１Ｒｂ，２Ｒｂで横断方向に切断してこの既設杭１，２を引抜部１１，２１と残置部１２，２２とに分断し、前記引抜部１１，２１を地盤Ｇの上方へ所望の高さｈ１，ｈ２だけ移動させるものである。
【００２８】
〔第１の実施の形態〕
図１（ａ）〜（ｉ）は、本実施の形態の既設杭の撤去方法の手順を示す縦断面図である。図２（ａ）〜図２（ｄ）は、本実施の形態で、既設杭１の引抜部１１の側周の地盤との間の摩擦力を低減させる手順を示す縦断面図であり、図２（ｅ）は、図２（ｄ）におけるＡ−Ａ断面図である。
【００２９】
［１］　図１（ａ）に示すように、既設杭１のうち、シールド通過予定断面Ｓと干渉する部位を含むように、撤去すべき部位１Ｒを設定する。この撤去すべき部位の下端１Ｒｂより上方が、引抜部１１となる。そして、図２（ａ）〜図２（ｄ）に示すように、既設杭１の引抜部１１の側周の地盤Ｇ中に注入ロッド６１を挿入し、これに高圧ポンプ６から滑材５２を送り込んで、注入ロッド６１に設けられた噴射口から滑材６２を噴射する。これにより、図２（ｅ）に示すように、引抜部１１の側周で地盤Ｇの土と滑材６２とが混合し、引抜部１１とその側周の地盤Ｇとの摩擦力が低減される。
ここで、滑材６２としては、時間が経過すると硬化するものを用いる。
この後、以下に示す手順で、既設杭１の引抜部１１を地盤Ｇの上方へ高さｈ１だけ移動させる。
【００３０】
［２］　図１（ｂ）に示すように、既設杭１の内部に、その上端１ｔから撤去すべき部位１Ｒの下の残置部１２の途中まで到達するように、貫通孔１Ｈを穿設する。そして、この貫通孔１Ｈに、カッタ（図示せず）を挿入し、既設杭１をその撤去すべき部位１Ｒの下端の位置１Ｒｂで横断方向に切断して、引抜部１１と残置部１２とに分断する。
【００３１】
［３］　図１（ｃ）に示すように、貫通孔１Ｈにロッド３を挿入し、その先端３ａを残置部１２内の貫通孔１Ｈの底面１Ｈｂに当接させる。そして、引抜部１１とロッド３との上方に、既設杭の引上装置５を設置する。
既設杭の引上装置５は、ロッド３を押し引きするジャッキ（ロッド押引手段）５１と、このジャッキ５１を取り囲むように四方に等間隔で配置された４本のジャッキ（引抜部押引手段）５２とが互いに連結されて、概略構成されたものである。ジャッキ５２は、先端にチャック（挟持手段）５３ａが備えられたアーム５３を押し引きする。そして、対向する２本のアーム５３のチャック５３ａは、その間に引抜部１１の側面を挟みこんで、引抜部１１を挟持できるようになっている。ここでは、４本のアーム５３全てのチャック５３ａで、引抜部１１の上端１１ｔ直下の側面を挟みこんでおく。
【００３２】
［４］　この状態で、ジャッキ５２を停止したまま、ジャッキ５１でロッド３を長さｐ１だけ押し出す。このとき、図１（ｄ）に示すように、引抜部１１の荷重と、既設杭の引上装置５の荷重と、引抜部１１と地盤Ｇとの間の摩擦力との合力がロッド３にかかり、この力でロッド３の先端部３ａが残置部１２を押し付ける。また、その反力によって、既設杭の引上装置５とそのチャック５３ａに挟持された引抜部１１とが、高さｐ１だけ上昇する。また、このとき、引抜部１１と残置部１２とが互いに離隔され、その間に空洞Ｖが形成される。そこで、引抜部１１を上昇させながら、貫通孔１Ｈの内周面とロッド３の外周面との隙間から、空洞Ｖ内に高流動性土（充填材）４を充填する。
【００３３】
［５］　次に、引抜部１１の上端の側面を挟持する４つのチャック５３ａのうち、引抜部１１を間に挟んで対向する一対（２つ）のチャック５３ａを解放して、このチャック５３ａが備えられたアーム５３をジャッキ５２で長さｐ１だけ下方へ伸ばし、再びこのチャック５３ａで引抜部１１の側面を挟み込む。この状態で、他の一対（２つ）のチャック５３ａを解放し、同様にこのチャック５３ａが備えられたアーム５３をジャッキ５２で長さｐ１だけ下方へ伸ばし、再びこのチャック５３ａで引抜部１１の側面を挟み込む。これで、４つのチャック５３ａが、引抜部１１の上端１１ｔより高さｐ１だけ下方の位置１１ａ直下の側面を挟持する状態になる。
【００３４】
［６］　この状態で、図１（ｅ）に示すように、上記の位置１１ａで引抜部１１を横断方向に切断して、引抜部１１を長さｐ１だけ短縮する。
そして、図（ｆ）に示すように、ジャッキ５１とジャッキ５２とを同時に動作させて、ロッド３とアーム５３を長さｐ１だけ引き込み、既設杭の引上装置５を高さｐ１だけ下降させる。
【００３５】
［７］　この後、図１（ｇ）、図１（ｈ）に示すように、上記［４］〜［６］と同様の工程をもう一度繰り返す。すると、引抜部１１がさらに長さｐ１だけ地盤Ｇの上方へ移動され、引抜部１１の上端１１ｔから高さｐ１だけ下方の位置１１ａで引抜部１１が横断方向に切断され、引抜部１１が長さｐ１だけさらに短縮される。また、引抜部１１がさらに上昇したことにより拡大した空洞部Ｖに、高流動性土４が充填される。これで、引抜部１１が地盤の上方へ高さｈ１だけ移動された状態となる。
【００３６】
［８］　この状態で時間を経過させ、滑材６２が硬化するのを待ち、引抜部１１との側周の地盤Ｇとの間の摩擦力が所定値以上になるようにする。そして、引上装置５とロッド３とを撤去し、図１（ｉ）に示すように、引抜部１１のうち地盤Ｇの表面から突出して残った部分を必要に応じて切断し除去する。
【００３７】
〔第２の実施の形態〕
図３（ａ）〜図３（ｅ）は、本実施の形態の既設杭の撤去方法の手順を示す縦断面図である。図４は、本実施の形態における、既設杭２の引抜部２１の上端２１ｔ及び既設杭の引上装置９の詳細を示す縦断面図である。図５、図６はそれぞれ、図４におけるＡ−Ａ矢視図、Ｂ−Ｂ断面図である。図７は、既設杭の引上装置９によって、後述する引抜ブロック２１Ｇが上昇された状況を示す縦断面図である。
本実施の形態について、第１の実施の形態と同様の事項については、その記載の一部を省略する。
【００３８】
［１］　まず、図３（ａ）に示すように、既設杭２のうち、シールド通過予定断面Ｓと干渉する部位を含むように、撤去すべき部位２Ｒを設定する。この撤去すべき部位の下端２Ｒｂより上方が、引抜部２１となる。そして、図３（ｂ）、図３（ｃ）に示すように、既設杭２の引抜部２１の側周を覆うように、地盤Ｇ中に全周回転オールケーシング機７でケーシング７１を挿入する。そして、既設杭２の引抜部２１とケーシング７１との間に水やベントナイト等を加えて、ケーシング７１内の土砂を泥濘化し、これをポンプで吸い上げて除去する。これで、引抜部２１とその側周の地盤Ｇとの摩擦力が絶たれた状態となる。
【００３９】
［２］　図３（ｄ）に示すように、引抜部２１の側面とケーシング７１との間の空隙に、ワイヤソー８２を挿入する。そして、ワイヤソー機８の駆動部８１を駆動させ、ワイヤソー８２で既設杭１を撤去すべき部位１Ｒの下端の位置１Ｒｂで横断方向に切断して、引抜部２１と残置部２２とに分断する。
【００４０】
［３］　次に、図３（ｅ）に示すように、引抜部２１を後述する引上装置９で地盤Ｇの上方へ高さｈ２だけ移動させる。引抜部２１が上昇することによって、引抜部２１と残置部２２との間に形成される空洞Ｖには、が形成される。そこで、引抜部１１を上昇させながら、引抜部２１の側面とケーシング７１との間の空隙から、高流動性土（充填材）４を充填する。
ここで、［３］において、引抜部２１を既設杭の引上装置９で地盤Ｇの上方へ移動させる方法について、以下に詳述する。
【００４１】
［３−１］　ワイヤソー８２で、既設杭１を引抜部２１と残置部２２とに分断したら、図６に示すように、引抜部２１を、その縦断方向に切断して、８つの引抜ブロック２１Ａ〜２１Ｈに分割する。
【００４２】
［３−２］　図４に示すように、各引抜ブロック２１Ａ〜２１Ｈの上端部に貫通孔２Ｈを穿設する。そして、各貫通孔２Ｈに、異形ＰＣ鋼棒９６を挿入した状態で、貫通孔２Ｈ内に早強セメントモルタルを充填して硬化させ、異形ＰＣ鋼棒９６を各引抜ブロック２１Ａ〜２１Ｈに固定する。
【００４３】
［３−３］　そして、引抜部２（すなわち引抜ブロック２１Ａ〜２１Ｈ）の上方に、既設杭の引上装置９を設置する。
既設杭の引上装置９は、図４〜図６に示すように、８つの引抜ブロック２１Ａ〜２１Ｈにそれぞれ固定された異形ＰＣ鋼棒９６のうち４本を押し引き可能なジャッキ（ブロック押引手段）９１〜９４が、十字枠９０で互いに連結されて、概略構成されたものである。各ジャッキ９１〜９４のシリンダ９１ａ〜９４ａの先端部には、チャック（図示せず）が設けられ、このチャックで異形ＰＣ鋼棒９６の先端を挟持し、引抜ブロック２１Ａ〜２１Ｈを押し引き可能になっている。図４、図５は、引抜ブロック２１Ａ，２１Ｃ，２１Ｅ，２１Ｇに固定された異形ＰＣ鋼棒９６が、既設杭の引上装置９のジャッキ９１〜９４のシリンダ９１ａ〜９４ａに挟持された状態を示している。
【００４４】
［３−４］　この状態で、図７に示すように、ジャッキ９１〜９３を停止したまま、ジャッキ９４で引抜ブロック２１Ｇを高さｐ２だけ引き上げる。このとき、引抜ブロック７の荷重と、既設杭の引上装置９との荷重と、引抜ブロック７と地盤Ｇとの間の摩擦力との合力が、３つの引抜ブロック２１Ａ，２１Ｃ，２１Ｅによって負担される。また、このとき、引抜ブロック２１Ｇと残置部２２とが互いに離隔され、その間に空洞Ｖが形成される。そこで、引抜ブロック２１Ｇを上昇させながら、引抜部２１の側面とケーシング７１との間の空隙から、空洞Ｖ内に高流動性土（充填材）４を充填する。
【００４５】
［３−５］　上記［３−４］と同様に、他の３つの引抜ブロック２１Ａ，２１Ｃ，２１Ｅを順次上昇させ、そのとき拡大する上記空洞Ｖ内に高流動性土４を充填する。このとき、反力を負担する引抜ブロックの下方にすでに充填されている高流動性土が締め固められる。
【００４６】
［３−６］　既設杭の引上装置９をクレーンで吊りながら、各シリンダ９１ａ〜９４ａのチャックを解放し、引抜ブロック２１Ａ，２１Ｃ，２１Ｅ，２１Ｇを引抜ブロック２１Ａ，２１Ｃ，２１Ｅ，２１Ｇから取り外す。
そして、既設杭の引上装置９を４５度回転させ、各シリンダ９１ａ〜９４ａのチャックで、引抜ブロック２１Ｂ，２１Ｄ，２１Ｆ，２１Ｈに固定された異形ＰＣ鋼棒９６にそれぞれ挟持する。そして、各ジャッキ９１〜９４のシリンダ９１ａ〜９４ａを、図４に示すような元の位置に伸ばしておく。
そして、［３−４］、［３−５］と同様の工程を、引抜ブロック２１Ｂ，２１Ｄ，２１Ｆ，２１Ｈについて行う。これで、引抜ブロック２１Ａ〜２１Ｈの全て（すなわち引抜部２１全体）が、高さｐ２だけ地盤の上方へ移動されたことになる。この状態で、引抜部２１の上端２１ｔより高さｐ２だけ下方の位置２１ａで、引抜部２１を横断方向に切断して、引抜部２１を長さｐ２だけ短縮する。
【００４７】
［３−７］　引抜部２１が当初の位置から地盤Ｇの上方へ高さｈ２だけ移動されるまで、上記［３−２］〜［３−６］の工程を繰り返す。このとき、引抜部２１が高さｐ２ずつ地盤Ｇの上方へ移動されるとともに、引抜部２１がその上端２１ｔから高さｐ２だけ下方の位置２１ａで切断されて長さｐ２ずつ短縮されていく。引抜部２１（引抜ブロック２１Ａ〜２１Ｈ）がさらに上昇することにより拡大する空洞部Ｖには、逐次高流動性土４を充填するようにする。
【００４８】
［４］　この状態で、ケーシング７１を撤去し、既設杭２の引抜部２１とケーシング７１との間に形成されていた空隙に高流動性土を充填した後、この充填部分にセメントミルクを注入して、引抜部２１とその側周の地盤Ｇとの間の摩擦力を所定値以上にする。
【００４９】
上記第１の実施の形態及び第２の実施の形態に記載の既存杭の撤去方法によれば、既設杭１，２を、その撤去すべき部位１Ｒ，２Ｒの下端の位置１Ｒｂ，２Ｒｂで横断方向に切断してこの既設杭１，２を引抜部１１，２１と残置部１２，２２とに分断し、引抜部１１，２１を地盤Ｇの上方へ所望の高さｈ１，ｈ２だけ移動させるので、既存杭１，２の撤去すべき部位１Ｒ，２Ｒ以外の部位を地盤Ｇ中に残して、撤去すべき部位１Ｒ，２Ｒのみを撤去することができる。
また、既設杭１，２のうち引抜部１１，２１のみを上方へ移動させるので、この引抜部１１，２１を上方へ移動させるのに必要な力やエネルギーが、既設杭１，２全体を上方へ移動させる場合よりも小さくて済む。したがって、比較的径が大きい場所打ちコンクリート杭の撤去を簡便に行える。
特に、この撤去すべき部位１Ｒ，２Ｒが、既存杭１，２の長さ方向途上の一部であって、かつ地盤Ｇの表面より下方に位置しているので、既存杭１，２の撤去すべき部位１Ｒ，２Ｒとこれより上方の部位をともに撤去する場合よりも、既存杭１，２を上方へ移動させるのに必要な力やエネルギーが小さくて済み、既存杭１，２を撤去するための労力や費用を大幅に軽減できる。
【００５０】
また、引抜部１１，２１を所定長ｐ１，ｐ２だけ地盤Ｇの上方へ移動させ、引抜部１１，２１をその上端１１ｔ，２１ｔよりこの所定長ｐ１，ｐ２だけ下方の位置１１ａ，２１ａで横断方向に切断して短縮することを繰り返して、引抜部１１，２１を地盤Ｇの上方へ移動させるので、引抜部１１，２１を上方へ移動させる引上装置４，９のストロークが短くて済む。
したがって、既設杭１，２の上方の空間に制約があるような狭隘な箇所でも、既設杭１，２の撤去すべき部位１Ｒ、２Ｒの撤去を行いやすい。
【００５１】
また、引抜部１１，２１を地盤Ｇの上方へ移動させる時、この引抜部１１，２１とその側周の地盤Ｇとの間の摩擦力を絶つか又は低減させておくので、引抜部１１，２１を地盤Ｇの上方に移動させる引上装置４，９の出力が小さくて済み、使用するエネルギーも低減できる。
【００５２】
また、引抜部１１，２１が上方に移動することによって形成される空洞Ｖに、高流動性土４を充填するので、地盤Ｇの上方へ移動された引抜部１１，２１が、この充填材に載置されて支持される。したがって、引抜部１１，２１を地盤Ｇ中の一定の高さに安定させることができる。
【００５３】
また、第１の実施の形態に記載の既設杭の撤去方法によれば、引抜部１１とその側周の地盤Ｇとの間の摩擦力を低減させるために、既設杭１の引抜部１１の側周の地盤中に注入する滑材６２として、時間が経過すると硬化するものを用いているので、引抜部１１を地盤Ｇの上方へ移動させた後で、時間が経過するにつれて、この引抜部１１とその側周の地盤Ｇとの間の摩擦力が所定値以上になり、地盤Ｇの上方へ移動された引抜部１１が、この摩擦力によって地盤Ｇ中の一定の高さに安定する。
【００５４】
また、第１の実施の形態に記載の既設杭の撤去方法、及び既設杭の引上装置５によれば、既設杭１の内部に、この既設杭１の上端１ｔから前記残置部１２の途中まで到達する貫通孔１Ｈを穿設し、この貫通孔１Ｈにロッド３を挿入してその先端３ａを残置部１２内の貫通孔１Ｈの底面１Ｈｂに当接させ、このロッド３に反力を負担させながら引抜部１１を地盤Ｇの上方へ移動させるので、引抜部１１を地盤Ｇの上方へ移動させる時に、反力を負担させるための支持面を地盤Ｇの表面の既存杭１の側周部などに確保する必要がない。
したがって、既設杭１の側周部に作業余地が確保できない狭隘な箇所でも、引抜部１１を地盤Ｇの上方へ移動させることができる。
【００５５】
また、第２の実施の形態に記載の既設杭の撤去方法によれば、引抜部２１をその縦断方向に切断して複数の引抜ブロック２１Ａ〜２１Ｈに分割するが、各引抜ブロック２１Ａ〜２１Ｈの重量やこれと周面の地盤との摩擦力は、引抜部全体の重量やこれと周面の地盤との摩擦力に対して、およそ上記分割数分の１である。つまり、これら引抜ブロック２１Ａ〜２１Ｈを順次地盤Ｇの上方へ移動させるのに必要な力は、引抜部２１全体を同時に地盤Ｇの上方へ移動させるのに必要な力に対して、およそ上記分割数分の１である。そして、各引抜ブロック２１Ａ〜２１Ｈを順次地盤Ｇの上方へ移動させるので、これら引抜ブロック２１Ａ〜２１Ｈの移動を行う引上装置９は、引抜ブロック２１Ａ〜２１Ｈのうち一つを上方に移動させることができる出力を備えていれば良く、引抜部２１全体を同時に上方へ移動させる場合に比べて小型の引上装置を用いて、引抜部２１を地盤Ｇの上方へ移動させることができる。
また、既設杭２が、比較的径が大きい場所打ちコンクリート杭である場合、上記の効果が、顕著に現れる。
【００５６】
また、引抜部２１を地盤Ｇの上方へ移動させた後で、このケーシング７１を除去し、既設杭２の引抜部２１とケーシング７１との間に形成されていた空隙に高流動性土を充填した後、この充填部分にセメントミルクを注入するので、引抜部２１とその側周の地盤Ｇとの間の摩擦力が所定値以上になり、地盤Ｇの上方へ移動された引抜部２１が、この摩擦力によって地盤Ｇ中の一定の高さに安定する。
【００５７】
また、第２の実施の形態に記載の既設杭の撤去方法、及び既設杭の引上装置９によれば、引抜ブロック２１Ａ〜２１Ｈの少なくとも一つ２１Ａ，２１Ｃ，２１Ｅに反力を負担させながら他の少なくとも一つの引抜ブロック２１Ｇを地盤Ｇの上方へ移動させることを繰り返して、各引抜ブロック２１Ａ〜２１Ｈを順次地盤Ｇの上方へ移動させるので、各引抜ブロック２１Ａ〜２１Ｈを引き上げる時に、反力を負担させるための支持面を地盤Ｇの表面の既存杭１の側周部などに確保する必要がない。
したがって、既設杭２の側周部に作業余地が確保できない狭隘な箇所でも、引抜部２１を地盤Ｇの上方へ移動させることができる。
【００５８】
なお、本発明の既設杭の撤去方法は、上記の実施の形態に限定されることなく、本発明の趣旨を逸脱しない範囲において、種々の改良並びに設計の変更を行っても良い。
例えば、上記各実施の形態では、既存杭１，２のうち、その長さ方向の一部であって、かつ地盤Ｇの表面より下方に位置する部位１Ｒ，２Ｒのみを撤去しているが、本発明によれば、既存杭のうち、その長さ方向の任意の部位を撤去することが可能である。
その他、具体的な細部構造等についても適宜に変更可能であることは勿論である。
【００５９】
【発明の効果】
請求項１に記載の発明によれば、既設杭を、その撤去すべき部位の下端の位置で横断方向に切断してこの既設杭を引抜部と残置部とに分断し、引抜部を地盤の上方へ所望の高さだけ移動させるので、既存杭の撤去すべき部位以外の部位を地盤中に残して、撤去すべき部位のみを撤去することができる。
また、既設杭のうち引抜部のみを上方へ移動させるので、この引抜部を上方へ移動させるのに必要な力やエネルギーが、既設杭全体を上方へ移動させる場合よりも小さくて済む。したがって、比較的径が大きい場所打ちコンクリート杭の撤去を簡便に行える。
特に、この撤去すべき部位が、既存杭の長さ方向途上の一部であって、かつ地盤の表面より下方に位置する場合、既存杭の撤去すべき部位とこれより上方の部位をともに撤去する場合よりも、既存杭を上方へ移動させるのに必要な力やエネルギーが小さくて済み、既存杭を撤去するための労力や費用を大幅に軽減できる。
【００６０】
請求項２に記載の発明によれば、請求項１に記載の発明と同様の効果が得られるとともに、引抜部を所定長だけ地盤の上方へ移動させ、引抜部をその上端よりこの所定長だけ下方の位置で横断方向に切断して短縮することを繰り返して、引抜部を地盤の上方へ移動させるので、引抜部を上方へ移動させる機械のストロークが短くて済む。
したがって、既設杭の上方の空間に制約があるような狭隘な箇所でも、既設杭の撤去すべき部位の撤去を行いやすい。
【００６１】
請求項３に記載の発明によれば、請求項１又は２に記載の発明と同様の効果が得られるとともに、引抜部をその縦断方向に切断して複数の引抜ブロックに分割するが、各引抜ブロックの重量やこれと周面の地盤との摩擦力は、引抜部全体の重量やこれと周面の地盤との摩擦力に対して、およそ上記分割数分の１である。つまり、これら引抜ブロックを順次地盤Ｇの上方へ移動させるのに必要な力は、引抜部全体を同時に地盤の上方へ移動させるのに必要な力に対して、およそ上記分割数分の１である。そして、各引抜ブロックを順次地盤の上方へ移動させるので、これら引抜ブロックの移動を行う機械（引上装置）は、引抜ブロックのうち一つを上方に移動させることができる出力を備えていれば良く、引抜部全体を同時に上方へ移動させる場合に比べて小型の機械を用いて、引抜部を地盤の上方へ移動させることができる。
この効果は、比較的径が大きい場所打ちコンクリート杭の撤去を行う場合に、顕著に現れる。
【００６２】
請求項４に記載の発明によれば、請求項１〜３のいずれか一項に記載の発明と同様の効果が得られるとともに、既設杭の内部に、この既設杭の上端から前記残置部の途中まで到達する貫通孔を穿設し、この貫通孔にロッドを挿入してその先端を残置部内の貫通孔の底面に当接させ、このロッドに反力を負担させながら引抜部を地盤の上方へ移動させるので、引抜部を地盤の上方へ移動させる時に、反力を負担させるための支持面を地盤の表面の既存杭の側周部などに確保する必要がない。
したがって、既設杭の側周部に作業余地が確保できない狭隘な箇所でも、引抜部を地盤の上方へ移動させることができる。
【００６３】
請求項５に記載の発明によれば、請求項３に記載の発明と同様の効果が得られるとともに、引抜ブロックの少なくとも一つに反力を負担させながら他の少なくとも一つの引抜ブロックを地盤の上方へ移動させることを繰り返して、各引抜ブロックを順次地盤の上方へ移動させるので、各引抜ブロックを引き上げる時に、反力を負担させるための支持面を地盤の表面の既存杭の側周部などに確保する必要がない。
したがって、既設杭の側周部に作業余地が確保できない狭隘な箇所でも、引抜部を地盤の上方へ移動させることができる。
【００６４】
請求項６に記載の発明によれば、請求項１〜５のいずれか一項に記載の発明と同様の効果が得られるとともに、引抜部を地盤の上方へ移動させる時、この引抜部とその側周の地盤との間の摩擦力を絶つか又は低減させておくので、引抜部を地盤Ｇの上方に移動させる機械の出力が小さくて済み、使用するエネルギーも低減できる。
【００６５】
請求項７に記載の発明によれば、請求項１〜６のいずれか一項に記載の発明と同様の効果が得られるとともに、引抜部が上方に移動することによって形成される空洞に、充填材を充填するので、地盤の上方へ移動された引抜部が、この充填材に載置されて支持される。したがって、引抜部を地盤中の一定の高さに安定させることができる。
【００６６】
請求項８に記載の発明によれば、請求項１〜７のいずれか一項に記載の発明と同様の効果が得られるとともに、引抜部１１，２１を地盤Ｇの上方へ所望の高さｈ１，ｈ２だけ移動させた後、この引抜部１１，２１とその側周の地盤Ｇとの間の摩擦力を所定値以上にするので、地盤Ｇの上方へ移動された引抜部１１，２１が、この摩擦力によって地盤Ｇ中の一定の高さに安定する。
【００６７】
請求項９に記載の発明によれば、請求項４に記載の発明と同様の効果が得られる。
【００６８】
請求項１０に記載の発明によれば、請求項５に記載の発明と同様の効果が得られる。
【図面の簡単な説明】
【図１】本発明の既設杭の撤去方法の一例の手順を示す縦断面図である。
【図２】上記例における、引抜部とその側周の地盤との間の摩擦力を低減させる手順を示す図である。
【図３】本発明の既設杭の撤去方法の他の一例の手順を示す縦断面図である。
【図４】上記例における、引抜部の上端及び引上装置の詳細を示す縦断面図である。
【図５】図４におけるＡ−Ａ矢視図である。
【図６】図４におけるＢ−Ｂ断面図である。
【図７】上記例における、引抜ブロックの上昇状況を示す縦断面図である。
【符号の説明】
１，２　　　　　既設杭
１Ｈ　　　　　　貫通孔
１Ｒ，２Ｒ　　　（既設杭の）撤去すべき部分
１Ｒｂ，２Ｒｂ　（撤去すべき部分の）下端の位置
１ｈ，２ｈ　　　（引抜部の）上昇高さ
３　　　　　　　ロッド
４　　　　　　　充填材（高流動性土）
５，９　　　　　既設杭の引上装置
１１，２１　　　引抜部
１２，２２　　　残置部
２１Ａ〜２１Ｈ　引抜ブロック
５１　　　　　　ロッド押引手段（ジャッキ）
５２　　　　　　引抜部押引手段（ジャッキ）
５３　　　　　　アーム
５３ａ　　　　　挟持手段（チャック）
９１〜９４　　　ブロック押引手段（ジャッキ）
Ｇ　　　　　　　地盤
Ｖ　　　　　　　空洞[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an existing pile removing method and a lifting device, and more particularly to an existing pile removing method and a lifting device for removing a part of the existing pile in the length direction.
[0002]
[Prior art]
When a tunnel is built in the ground by the shield method, existing piles may remain buried in the route of the shield in urban areas. In this case, it is necessary to remove this existing pile before passing the shield.
[0003]
The existing pile can be removed by excavating the ground around the side of the existing pile and exposing it in the air, or by removing a steel pipe or other casing with a diameter larger than that of the existing pile so that it is concentric with the existing pile. By burying and pulling up this casing, a method of pulling up the existing pile together with the casing using the frictional resistance of the sand and sand between the casing and the existing pile, adding water or bentonite etc. into the casing, and removing the earth and sand in the casing There is a method of reducing only the existing pile by reducing the frictional resistance when raising the existing pile by mudging.
This type of technology is disclosed in, for example, Patent Document 1.
[0004]
In each of these methods, when the length of the existing pile buried in the ground is long, the ground excavation depth and the casing driving depth become long, requiring a lot of labor and cost, and the construction period is long.
In addition, when removing existing piles on the route that the shield is scheduled to pass as described above, it is not always necessary to remove the entire existing pile, and if only the portion of the existing pile that interferes with the planned passage position of the shield is removed. Good.
[0005]
[Patent Document 1]
JP-A-6-41960 (FIGS. 1 to 3)
[0006]
[Problems to be solved by the invention]
The problem of the present invention is that when the part to be removed of the existing pile is a part of the existing pile in the length direction, particularly when the part to be removed is located below the surface of the ground. An object of the present invention is to provide an existing pile removal method that can reduce labor and cost required for pile removal, and an existing pile pulling device that can be suitably used for the existing pile removal method.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the invention according to claim 1 is an existing installation in which, for example, as shown in FIGS. 1 and 3, at least a part of the existing piles 1 and 2 is moved upward and removed. A method for removing piles,
The existing piles 1 and 2 are cut in the transverse direction at positions 1Rb and 2Rb at the lower ends of the parts 1R and 2R to be removed, and the existing piles 1 and 2 are cut into the extraction portions 11 and 21 and the remaining portions 12 and 22. It cuts and the said extraction parts 11 and 21 are moved only the desired height h1 and h2 above the ground G, It is characterized by the above-mentioned.
Here, in order to divide an existing pile into a drawing portion and a remaining portion, for example, as shown in FIG. 1B, a cutter (not shown) inserted into a through hole 1H drilled in the existing pile 1 is shown. 3) or the position of the lower end of the site where the existing pile should be removed by a wire saw 82 or the like inserted into the gap between the existing pile 2 and the casing 71 surrounding the side periphery thereof as shown in FIG. Take a method such as cutting with a.
[0008]
According to the first aspect of the present invention, the existing pile is cut in the transverse direction at the lower end of the part to be removed, and the existing pile is divided into the extraction portion and the remaining portion, and the extraction portion is separated from the ground. Since the desired height is moved upward, it is possible to remove only the portion to be removed, leaving the portion other than the portion to be removed of the existing pile in the ground.
In addition, since only the extraction portion of the existing pile is moved upward, the force and energy required to move the extraction portion upward can be smaller than when the entire existing pile is moved upward. Therefore, the cast-in-place concrete pile having a relatively large diameter can be easily removed.
In particular, when this part to be removed is a part of the existing pile in the length direction and is located below the surface of the ground, both the part to be removed from the existing pile and the part above it are removed. The force and energy required to move the existing pile upward can be smaller than the case where the existing pile is moved, and the labor and cost for removing the existing pile can be greatly reduced.
[0009]
The invention according to claim 2 is, for example, as shown in FIGS. 1 and 4, in the method for removing the existing pile according to claim 1,
The extraction portions 11 and 21 are moved above the ground G by predetermined lengths p1 and p2, and the extraction portions 11 and 21 are moved in the transverse direction at positions 11a and 21a below the upper ends 11t and 21t by the predetermined lengths p1 and p2. By repeating the cutting and shortening, the extraction portions 11 and 21 are moved above the ground G.
[0010]
According to the second aspect of the present invention, the same effect as that of the first aspect of the invention can be obtained, and the extraction portion is moved above the ground by a predetermined length, and the extraction portion is moved from the upper end by this predetermined length. By repeatedly cutting and shortening in the transverse direction at the lower position and moving the extraction portion above the ground, the stroke of the machine for moving the extraction portion upward can be shortened.
Therefore, it is easy to remove the site where the existing pile should be removed even in a narrow place where the space above the existing pile is restricted.
[0011]
Invention of Claim 3 is the removal method of the existing pile of Claim 1 or 2, as shown, for example in FIGS. 4-7,
The drawing portion 21 is cut in the longitudinal direction to be divided into a plurality of drawing blocks 21A to 21H, and the drawing blocks 21A to 21H are sequentially moved above the ground G.
[0012]
According to the invention described in claim 3, while the same effect as that of the invention described in claim 1 or 2 can be obtained, the drawing portion is cut in the longitudinal direction and divided into a plurality of drawing blocks. The weight of the block and the frictional force between it and the ground on the peripheral surface are approximately a fraction of the above-mentioned number of divisions with respect to the weight of the entire extraction part and the frictional force between this and the ground on the peripheral surface. In other words, the force required to move these drawing blocks sequentially above the ground G is approximately one-fifth of the above-mentioned number of divisions with respect to the force required to move the entire drawing portion simultaneously above the ground. . Since each drawing block is sequentially moved above the ground, a machine (pulling device) for moving these drawing blocks has an output capable of moving one of the drawing blocks upward. It is possible to move the extraction part to the upper side of the ground using a small machine as compared with the case where the entire extraction part is moved upward at the same time.
This effect is conspicuous when removing cast-in-place concrete piles having a relatively large diameter.
[0013]
The invention according to claim 4 is a method for removing an existing pile according to any one of claims 1 to 3, for example as shown in FIG.
A through hole 1H reaching from the upper end 1t of the existing pile 1 to the middle of the remaining portion 12 is drilled in the existing pile 1, and the rod 3 is inserted into the through hole, and the tip 3a is inserted into the remaining portion. 12, the pull-out portion 11 is moved above the ground G while being brought into contact with the bottom surface 1Hb of the through hole 1H in 12 and applying a reaction force to the rod 3.
Here, when the extraction part 11 is moved above the ground G, a cavity is formed between the extraction part 11 and the remaining part 12, and the rod 3 is exposed inside the cavity. From the viewpoint of preventing the buckling of the rod 3, for example, as shown in FIG. 1, every time the extraction portion 11 is moved a predetermined length above the ground G, the cavity 4 is filled with a filler 4 such as backfilling soil. Is preferred.
[0014]
According to the invention described in claim 4, the same effect as in the invention described in any one of claims 1 to 3 can be obtained, and the remaining portion can be formed inside the existing pile from the upper end of the existing pile. A through-hole that reaches partway is drilled, a rod is inserted into this through-hole, its tip is brought into contact with the bottom of the through-hole in the remaining part, and the pulling part is placed above the ground while bearing a reaction force on this rod. Therefore, when moving the extraction part above the ground, it is not necessary to secure a support surface for bearing a reaction force on the side peripheral part of the existing pile on the surface of the ground.
Therefore, even in a narrow place where there is no room for work on the side peripheral part of the existing pile, the extraction part can be moved above the ground.
[0015]
The invention according to claim 5 is, for example, as shown in FIGS. 4 and 7, in the method for removing the existing pile according to claim 3,
Each of the drawing blocks 21A to 21H is repeatedly moved by moving at least one other drawing block 21G above the ground G while applying a reaction force to at least one of the drawing blocks 21A to 21H. It is characterized by sequentially moving above the ground G.
[0016]
According to the invention described in claim 5, the same effect as that of the invention described in claim 3 can be obtained, and at least one other drawing block can be placed on the ground while causing at least one drawing block to bear a reaction force. Repeatedly moving upward, each extraction block is moved sequentially above the ground, so when pulling each extraction block, the support surface for bearing the reaction force is the side periphery of the existing pile on the surface of the ground, etc. There is no need to secure it.
Therefore, even in a narrow place where there is no room for work on the side peripheral part of the existing pile, the extraction part can be moved above the ground.
[0017]
Invention of Claim 6 is the removal method of the existing pile as described in any one of Claims 1-5 as shown, for example in FIG. 2, FIG.
When the pulling portions 11 and 21 are moved above the ground G, the frictional force between the pulling portions 11 and 21 and the ground G on the side periphery thereof is stopped or reduced.
Here, in order to cut off the frictional force between the extraction portion and the ground on the side thereof, for example, as shown in FIG. 4, a casing is formed in the ground so as to cover the side periphery of the extraction portion 21 of the existing pile 2. A method such as inserting 71 is adopted.
Moreover, in order to reduce the frictional force between the extraction part and the ground of the side periphery, as shown in FIG. 2, for example, in the ground of the side periphery of the extraction part 11 of the existing pile 1, a lubricant 62 or the like Use a method such as injecting a friction reducer.
[0018]
According to the invention described in claim 6, the same effect as that of any one of the inventions described in claims 1 to 5 can be obtained, and when the extraction portion is moved above the ground, the extraction portion and its Since the frictional force with the ground around the side is stopped or reduced, the output of the machine that moves the extraction part above the ground G can be small, and the energy used can also be reduced.
[0019]
The invention according to claim 7 is, for example, as shown in FIGS. 1 and 3, in the method for removing an existing pile according to any one of claims 1 to 6,
Filling material (high fluidity soil) 4 is filled in the cavity V formed by the extraction portions 11 and 21 moving upward.
[0020]
According to the seventh aspect of the present invention, the same effect as that of any one of the first to sixth aspects of the present invention can be obtained, and the cavity formed by moving the drawing portion upward is filled. Since the material is filled, the drawing portion moved upward from the ground is placed and supported on the filling material. Therefore, the extraction portion can be stabilized at a certain height in the ground.
[0021]
Invention of Claim 8 is the removal method of the existing pile as described in any one of Claims 1-7,
After the extraction portions 11 and 21 are moved above the ground G by the desired heights h1 and h2, the frictional force between the extraction portions 11 and 21 and the ground G on the side periphery thereof is set to a predetermined value or more. It is characterized by that.
Here, in order to make the frictional force between the extraction part and the ground around the side of the pile more than a predetermined value, for example, a friction increasing agent such as cement milk is injected into the ground around the extraction part of the existing pile. Use a method such as
Further, as described in claim 6, when the extraction portion is moved above the ground, if the frictional force between the extraction portion and the ground on the side thereof is stopped or reduced, the extraction portion is In order to make the frictional force between the extracted portion and the ground around the side after moving it above the ground above a predetermined value, the following method is adopted.
First, as shown in FIG. 4, the casing 71 is inserted into the ground so as to cover the side periphery of the extraction portion 21 of the existing pile 2, and the frictional force between the extraction portion 21 and the ground G on the side periphery is inserted. When it has been cut off, the casing 71 is removed, and after filling the gap formed between the drawn portion 21 of the existing pile 2 and the casing 71 with, for example, high-fluidity soil, the filling portion is filled with cement milk. The frictional force between the extraction portion 21 and the ground G on the side periphery thereof is set to a predetermined value or more.
In addition, as shown in FIG. 2, a friction reducing agent such as a lubricant 62 is injected into the ground around the side of the extraction portion 11 of the existing pile 1 so that the space between the extraction portion 11 and the ground G on the side periphery thereof. When the frictional force is cut off, if this sliding material 62 is hardened over time, it can be pulled out without any special treatment after the pulling portion 11 is moved above the ground G. The frictional force between the portion 11 and the ground G on the side periphery can be made a predetermined value or more.
[0022]
According to the eighth aspect of the present invention, the same effects as those of the first aspect of the present invention can be obtained, and the pull-out portions 11 and 21 can be moved above the ground G to a desired height h1. , H2 and then the frictional force between the extraction parts 11 and 21 and the ground G on the side thereof is set to a predetermined value or more, so that the extraction parts 11 and 21 moved above the ground G are This frictional force stabilizes the ground G at a certain height.
[0023]
The invention described in claim 9 is, as shown in FIG. 1 for example, an existing pile lifting device 5 used in the method for removing an existing pile according to claim 4,
Rod pushing and pulling means (jack) 51 capable of pushing and pulling the rod 3;
A plurality of pull-out portion push-pull means (jacks) 52 attached to the rod push-pull means 51 and surrounding the rod push-pull means 51 at a predetermined interval;
An arm 53 that is pushed and pulled in parallel with the rod 3 by each of the pulling portion pushing and pulling means 52;
It is provided with clamping means (chuck) 53a attached to the tip of each arm 53 and capable of clamping by sandwiching the side surface of the extraction portion 11.
[0024]
According to the ninth aspect of the invention, the same effect as that of the fourth aspect of the invention can be obtained.
[0025]
The invention described in claim 10 is, as shown in FIGS. 4 and 7, for example, an existing pile lifting device 9 used in the method for removing an existing pile according to claim 5,
Two or more block pushing means (jacks) 91-94 capable of pushing and pulling each of the drawing blocks 21A-21H are provided,
Each of the block pushing / pulling means 91 to 94 is fixed in parallel to each other so that the drawing blocks 21A to 21H connected thereto can be pushed and pulled simultaneously by mutually independent operations.
[0026]
According to the invention described in claim 10, the same effect as that of the invention described in claim 5 can be obtained.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Below, embodiment of the removal method of the existing pile of this invention is described with reference to drawings.
The removal method of the existing pile described in 1st Embodiment and 2nd Embodiment is a removal method of the existing pile which moves both a part of the length direction of an existing pile upwards, and is removed. As shown in FIGS. 1 and 3, the existing piles 1 and 2 are cut in the transverse direction at positions 1Rb and 2Rb at the lower ends of the portions 1R and 2R to be removed, and the existing piles 1 and 2 are pulled out by a pulling portion 11. , 21 and the remaining portions 12, 22, and the extraction portions 11, 21 are moved above the ground G by a desired height h1, h2.
[0028]
[First Embodiment]
Fig.1 (a)-(i) is a longitudinal cross-sectional view which shows the procedure of the removal method of the existing pile of this Embodiment. FIG. 2A to FIG. 2D are longitudinal sectional views showing a procedure for reducing the frictional force between the pulling portion 11 of the existing pile 1 and the ground around the side in the present embodiment. 2 (e) is a cross-sectional view taken along line AA in FIG. 2 (d).
[0029]
[1] As shown in FIG. 1A, a part 1 R to be removed is set so as to include a part of the existing pile 1 that interferes with the shield passing cross-section S. The extraction part 11 is above the lower end 1Rb of the part to be removed. Then, as shown in FIGS. 2 (a) to 2 (d), an injection rod 61 is inserted into the ground G on the side periphery of the extraction portion 11 of the existing pile 1, and the lubricant 52 is supplied from the high-pressure pump 6 to this. Then, the lubricant 62 is injected from the injection port provided in the injection rod 61. Thereby, as shown in FIG.2 (e), the soil of the ground G and the sliding material 62 mix in the side periphery of the extraction part 11, and the frictional force of the extraction part 11 and the ground G of the side periphery is reduced. The
Here, as the lubricant 62, a material that hardens over time is used.
Thereafter, the extraction portion 11 of the existing pile 1 is moved above the ground G by the height h1 in the following procedure.
[0030]
[2] As shown in FIG. 1B, a through hole 1H is drilled in the existing pile 1 so as to reach the middle of the remaining portion 12 below the portion 1R to be removed from the upper end 1t thereof. . Then, a cutter (not shown) is inserted into the through-hole 1H, and the existing pile 1 is cut in the transverse direction at the position 1Rb at the lower end of the portion 1R to be removed, and the extracted portion 11 and the remaining portion 12 are separated. Divide.
[0031]
[3] As shown in FIG. 1C, the rod 3 is inserted into the through hole 1H, and the tip 3a is brought into contact with the bottom surface 1Hb of the through hole 1H in the remaining portion 12. Then, an existing pile pulling device 5 is installed above the pulling portion 11 and the rod 3.
The existing pile pulling device 5 includes a jack (rod push / pull means) 51 that pushes and pulls the rod 3 and four jacks (pull-out part push / push means arranged at equal intervals in four directions so as to surround the jack 51. ) 52 are connected to each other and roughly configured. The jack 52 pushes and pulls an arm 53 having a chuck (clamping means) 53a at the tip. And the chuck | zipper 53a of the two arms 53 which oppose can pinch | pull the extraction part 11 by pinching the side surface of the extraction part 11 between them. Here, the side surfaces immediately below the upper end 11t of the extraction portion 11 are sandwiched between the chucks 53a of all the four arms 53.
[0032]
[4] In this state, with the jack 52 stopped, the jack 3 pushes out the rod 3 by the length p1. At this time, as shown in FIG. 1 (d), the resultant force of the load of the extraction portion 11, the load of the existing pile lifting device 5, and the frictional force between the extraction portion 11 and the ground G is applied to the rod 3. The tip 3a of the rod 3 presses the remaining portion 12 with this force. Further, the reaction force raises the existing pile pulling device 5 and the pulling portion 11 held by the chuck 53a by a height p1. At this time, the extraction portion 11 and the remaining portion 12 are separated from each other, and a cavity V is formed therebetween. Therefore, the high-fluidity soil (filler) 4 is filled into the cavity V through the gap between the inner peripheral surface of the through hole 1H and the outer peripheral surface of the rod 3 while raising the extraction portion 11.
[0033]
[5] Next, among the four chucks 53a that sandwich the upper end side surface of the extraction portion 11, a pair (two) of the chucks 53a facing each other with the extraction portion 11 interposed therebetween is released so that the chuck 53a The provided arm 53 is extended downward by a length p1 with the jack 52, and the side surface of the extraction portion 11 is sandwiched again by the chuck 53a. In this state, the other pair (two) of the chucks 53a are released, and similarly, the arm 53 provided with the chucks 53a is extended downward by the length p1 by the jack 52, and the chuck 53a is used again to pull out the extraction portion 11. Insert the side. As a result, the four chucks 53a sandwich the side surface immediately below the position 11a that is lower than the upper end 11t of the extraction portion 11 by the height p1.
[0034]
[6] In this state, as shown in FIG. 1 (e), the extraction portion 11 is cut in the transverse direction at the position 11a to shorten the extraction portion 11 by the length p1.
Then, as shown in FIG. 5 (f), the jack 51 and the jack 52 are operated simultaneously, the rod 3 and the arm 53 are pulled by the length p1, and the existing pile lifting device 5 is lowered by the height p1.
[0035]
[7] Thereafter, as shown in FIGS. 1 (g) and 1 (h), the same steps as in [4] to [6] are repeated once more. Then, the extraction part 11 is further moved above the ground G by the length p1, the extraction part 11 is cut in the transverse direction at a position 11a below the height p1 from the upper end 11t of the extraction part 11, and the extraction part 11 is long. Further shortened by p1. Further, the high fluidity soil 4 is filled into the cavity V that has been expanded by further raising the extraction portion 11. Thus, the extraction portion 11 is moved upward by a height h1 above the ground.
[0036]
[8] Allow time to elapse in this state, wait for the lubricant 62 to harden, and set the frictional force between the pulling portion 11 and the ground G on the side circumference to a predetermined value or more. And the pulling-up apparatus 5 and the rod 3 are removed, and as shown in FIG.1 (i), the part which protruded from the surface of the ground G among the extraction parts 11 is cut | disconnected and removed as needed.
[0037]
[Second Embodiment]
Fig.3 (a)-FIG.3 (e) are longitudinal cross-sectional views which show the procedure of the removal method of the existing pile of this Embodiment. FIG. 4 is a longitudinal cross-sectional view showing details of the upper end 21t of the pull-out portion 21 of the existing pile 2 and the existing pile lifting device 9 in the present embodiment. 5 and FIG. 6 are respectively an AA arrow view and a BB sectional view in FIG. FIG. 7 is a longitudinal cross-sectional view showing a situation in which a drawing block 21G described later is raised by the existing pile pulling device 9.
About this embodiment, a part of the description is omitted about the same matter as the first embodiment.
[0038]
[1] First, as shown in FIG. 3A, a part 2R to be removed is set so as to include a part of the existing pile 2 that interferes with the shield passing cross-section S. A portion above the lower end 2Rb of the portion to be removed is the extraction portion 21. And as shown in FIG.3 (b) and FIG.3 (c), the casing 71 is inserted in the ground G by the all-round rotation all casing machine 7 so that the side periphery of the extraction part 21 of the existing pile 2 may be covered. And water, a bentonite, etc. are added between the extraction part 21 and the casing 71 of the existing pile 2, and the earth and sand in the casing 71 are made muddy, and this is sucked up with a pump and removed. As a result, the frictional force between the drawing portion 21 and the ground G on the side periphery is cut off.
[0039]
[2] As shown in FIG. 3D, the wire saw 82 is inserted into the gap between the side surface of the drawing portion 21 and the casing 71. And the drive part 81 of the wire saw machine 8 is driven, it cut | disconnects in the cross direction in the position 1Rb of the lower end of the site | part 1R which should remove the existing pile 1 with the wire saw 82, and it divides | segments into the extraction part 21 and the remaining part 22.
[0040]
[3] Next, as shown in FIG. 3 (e), the pull-out portion 21 is moved upward by the height h2 above the ground G by the pulling device 9 described later. As the drawing portion 21 is raised, a cavity V is formed between the drawing portion 21 and the remaining portion 22. Therefore, the high fluidity soil (filler) 4 is filled from the gap between the side surface of the extraction portion 21 and the casing 71 while raising the extraction portion 11.
Here, in [3], the method of moving the extraction part 21 to the upper side of the ground G by the existing pile lifting device 9 will be described in detail below.
[0041]
[3-1] When the existing pile 1 is divided into the drawing portion 21 and the remaining portion 22 with the wire saw 82, the drawing portion 21 is cut in the longitudinal direction as shown in FIG. Divide into ~ 21H.
[0042]
[3-2] As shown in FIG. 4, a through hole 2H is formed at the upper end of each of the drawing blocks 21A to 21H. Then, with the deformed PC steel rod 96 inserted into each through hole 2H, the through hole 2H is filled with an early-strength cement mortar and hardened, and the deformed PC steel rod 96 is fixed to each drawing block 21A to 21H. .
[0043]
[3-3] Then, the existing pile pulling device 9 is installed above the drawing portion 2 (that is, the drawing blocks 21A to 21H).
As shown in FIGS. 4 to 6, the existing pile pulling device 9 is a jack (block push-pull) that can push and pull four of the deformed PC steel rods 96 fixed to the eight pull-out blocks 21 A to 21 H, respectively. Means) 91 to 94 are connected to each other by a cross frame 90 and are roughly configured. A chuck (not shown) is provided at the tip of the cylinders 91a to 94a of each jack 91 to 94, and the tip of the deformed PC steel rod 96 is held by this chuck so that the drawing blocks 21A to 21H can be pushed and pulled. It has become. 4 and 5 show a state in which the deformed PC steel rod 96 fixed to the drawing blocks 21A, 21C, 21E, and 21G is sandwiched between the cylinders 91a to 94a of the jacks 91 to 94 of the pulling device 9 of the existing pile. Show.
[0044]
[3-4] In this state, as shown in FIG. 7, with the jacks 91 to 93 stopped, the extraction block 21G is pulled up by the height p2 with the jack 94. At this time, the combined force of the load of the extraction block 7, the load of the existing pile lifting device 9, and the frictional force between the extraction block 7 and the ground G is borne by the three extraction blocks 21A, 21C, and 21E. Is done. At this time, the drawing block 21G and the remaining portion 22 are separated from each other, and a cavity V is formed therebetween. Therefore, the high-fluidity soil (filler) 4 is filled into the cavity V from the gap between the side surface of the drawing portion 21 and the casing 71 while raising the drawing block 21G.
[0045]
[3-5] Similarly to the above [3-4], the other three extraction blocks 21A, 21C, and 21E are sequentially raised, and the high-fluidity soil 4 is filled into the cavity V that is enlarged at that time. At this time, the high-fluidity soil already filled under the drawing block bearing the reaction force is compacted.
[0046]
[3-6] While lifting the existing pile lifting device 9 with a crane, the chucks of the cylinders 91a to 94a are released, and the extraction blocks 21A, 21C, 21E, and 21G are removed from the extraction blocks 21A, 21C, 21E, and 21G. .
Then, the existing pile pulling device 9 is rotated 45 degrees, and is clamped by the deformed PC steel rod 96 fixed to the drawing blocks 21B, 21D, 21F, and 21H by the chucks of the cylinders 91a to 94a. And the cylinders 91a-94a of each jack 91-94 are extended to the original position as shown in FIG.
And the process similar to [3-4] and [3-5] is performed about drawing block 21B, 21D, 21F, and 21H. Thus, all of the extraction blocks 21A to 21H (that is, the entire extraction portion 21) have been moved above the ground by the height p2. In this state, the drawing portion 21 is cut in the transverse direction at a position 21a that is lower than the upper end 21t of the drawing portion 21 by a height p2, and the drawing portion 21 is shortened by a length p2.
[0047]
[3-7] The above steps [3-2] to [3-6] are repeated until the extraction unit 21 is moved from the initial position by a height h2 above the ground G. At this time, the extraction portion 21 is moved upward by the height p2 above the ground G, and the extraction portion 21 is cut from the upper end 21t by a height p2 at a position 21a below and shortened by the length p2. The cavity portion V that expands as the drawing portion 21 (drawing blocks 21 A to 21 H) further rises is sequentially filled with the high fluidity soil 4.
[0048]
[4] In this state, the casing 71 is removed, and after filling the gap formed between the extraction portion 21 of the existing pile 2 and the casing 71 with high-fluidity soil, cement milk is injected into this filling portion. Then, the frictional force between the extraction portion 21 and the ground G on the side periphery thereof is set to a predetermined value or more.
[0049]
According to the existing pile removal method described in the first embodiment and the second embodiment, the existing piles 1 and 2 are crossed at the positions 1Rb and 2Rb at the lower ends of the portions 1R and 2R to be removed. Since the existing piles 1 and 2 are cut into the direction and divided into the extraction portions 11 and 21 and the remaining portions 12 and 22, the extraction portions 11 and 21 are moved above the ground G by the desired heights h1 and h2. The parts other than the parts 1R and 2R to be removed of the existing piles 1 and 2 can be left in the ground G, and only the parts 1R and 2R to be removed can be removed.
Moreover, since only the extraction parts 11 and 21 are moved upward among the existing piles 1 and 2, the force and energy required to move the extraction parts 11 and 21 upward will cause the existing piles 1 and 21 to move upward. It can be smaller than when moving to. Therefore, the cast-in-place concrete pile having a relatively large diameter can be easily removed.
In particular, since the parts 1R and 2R to be removed are part of the existing piles 1 and 2 in the length direction and are located below the surface of the ground G, the existing piles 1 and 2 are removed. The force and energy required to move the existing piles 1 and 2 to the upper side are smaller than the case where both the parts 1R and 2R to be removed are removed, and the existing piles 1 and 2 are removed. Can greatly reduce labor and cost.
[0050]
Further, the extraction portions 11 and 21 are moved above the ground G by the predetermined lengths p1 and p2, and the extraction portions 11 and 21 are moved in the transverse direction at positions 11a and 21a below the upper ends 11t and 21t by the predetermined lengths p1 and p2. Since the pulling portions 11 and 21 are moved upward above the ground G by repeatedly cutting and shortening, the strokes of the pulling devices 4 and 9 for moving the pulling portions 11 and 21 upward can be shortened.
Therefore, it is easy to remove the parts 1R and 2R to be removed from the existing piles 1 and 2 even in a narrow place where the space above the existing piles 1 and 2 is limited.
[0051]
Further, when the pulling portions 11 and 21 are moved above the ground G, the frictional force between the pulling portions 11 and 21 and the ground G on the side thereof is stopped or reduced. The output of the lifting devices 4 and 9 for moving the 21 to the upper side of the ground G can be small, and the energy used can be reduced.
[0052]
Further, since the high-fluidity soil 4 is filled in the cavity V formed by the upward movement of the extraction portions 11 and 21, the extraction portions 11 and 21 moved upward of the ground G are used as the filler. Mounted and supported. Therefore, the extraction parts 11 and 21 can be stabilized at a certain height in the ground G.
[0053]
Moreover, according to the removal method of the existing pile described in 1st Embodiment, in order to reduce the frictional force between the extraction part 11 and the ground G of the side periphery, of the extraction part 11 of the existing pile 1 Since the sliding material 62 to be injected into the ground on the side circumference is a material that hardens over time, after the extraction unit 11 is moved above the ground G, this extraction unit is used as time elapses. The frictional force between the ground 11 and the ground G on the side thereof becomes equal to or greater than a predetermined value, and the extraction portion 11 moved upward of the ground G is stabilized at a certain height in the ground G by this frictional force.
[0054]
Moreover, according to the removal method of the existing pile described in 1st Embodiment, and the lifting apparatus 5 of the existing pile, it is in the middle of the said remaining part 12 from the upper end 1t of this existing pile 1 inside the existing pile 1. A through-hole 1H reaching up to is drilled, and a rod 3 is inserted into the through-hole 1H, and its tip 3a is brought into contact with the bottom surface 1Hb of the through-hole 1H in the remaining portion 12, and a reaction force is applied to the rod 3 Since the pulling part 11 is moved above the ground G while moving the pulling part 11 to the top of the ground G, the support surface for bearing the reaction force is used as the side peripheral part of the existing pile 1 on the surface of the ground G. There is no need to secure it.
Therefore, the extraction part 11 can be moved to the upper side of the ground G even in a narrow place where a working space cannot be secured in the side peripheral part of the existing pile 1.
[0055]
Moreover, according to the removal method of the existing pile described in 2nd Embodiment, although the extraction part 21 is cut | disconnected in the longitudinal direction and divided | segmented into several extraction blocks 21A-21H, each extraction block 21A-21H The weight and the frictional force between this and the peripheral ground are approximately one-fifth of the above-mentioned number of divisions with respect to the total weight of the extraction part and the frictional force between this and the peripheral ground. That is, the force required to move the extraction blocks 21A to 21H sequentially above the ground G is approximately the above-mentioned number of divisions with respect to the force required to move the entire extraction unit 21 simultaneously above the ground G. A fraction. And since each extraction block 21A-21H is moved to the upper direction of the ground G sequentially, the pulling-up apparatus 9 which moves these extraction blocks 21A-21H moves one of the extraction blocks 21A-21H upward. It is only necessary to have an output that can perform the above operation, and the pulling unit 21 can be moved above the ground G using a small pulling device as compared with the case where the entire pulling unit 21 is moved upward simultaneously.
Moreover, when the existing pile 2 is a cast-in-place concrete pile with a comparatively large diameter, said effect appears notably.
[0056]
Moreover, after moving the extraction part 21 to the upper side of the ground G, this casing 71 is removed, and the space formed between the extraction part 21 and the casing 71 of the existing pile 2 is filled with high-fluidity soil. Then, since the cement milk is injected into the filling portion, the frictional force between the extraction portion 21 and the ground G on the side thereof becomes a predetermined value or more, and the extraction portion 21 moved to above the ground G This frictional force stabilizes the ground G at a certain height.
[0057]
Moreover, according to the removal method of the existing pile as described in 2nd Embodiment, and the pulling-up apparatus 9 of the existing pile, while making at least one 21A, 21C, 21E of drawing block 21A-21H bear reaction force By repeating the movement of at least one other drawing block 21G above the ground G, the respective drawing blocks 21A to 21H are sequentially moved above the ground G. Therefore, when pulling up each drawing block 21A to 21H, the reaction force It is not necessary to secure a support surface for burdening the side periphery of the existing pile 1 on the surface of the ground G.
Therefore, the extraction part 21 can be moved to the upper side of the ground G even in a narrow place where a work space cannot be secured in the side peripheral part of the existing pile 2.
[0058]
In addition, the removal method of the existing pile of this invention is not limited to said embodiment, You may perform a various improvement and design change in the range which does not deviate from the meaning of this invention.
For example, in each of the above embodiments, among the existing piles 1 and 2, only the parts 1R and 2R that are part of the length direction and are located below the surface of the ground G are removed. According to this invention, it is possible to remove the arbitrary site | parts in the length direction among the existing piles.
In addition, it is needless to say that specific detailed structures and the like can be appropriately changed.
[0059]
【The invention's effect】
According to the first aspect of the present invention, the existing pile is cut in the transverse direction at the lower end of the part to be removed, and the existing pile is divided into the extraction portion and the remaining portion, and the extraction portion is separated from the ground. Since the desired height is moved upward, it is possible to remove only the portion to be removed, leaving the portion other than the portion to be removed of the existing pile in the ground.
In addition, since only the extraction portion of the existing pile is moved upward, the force and energy required to move the extraction portion upward can be smaller than when the entire existing pile is moved upward. Therefore, the cast-in-place concrete pile having a relatively large diameter can be easily removed.
In particular, when the part to be removed is a part of the existing pile in the length direction and is located below the surface of the ground, both the part to be removed from the existing pile and the part above it are removed. The force and energy required to move the existing pile upward can be smaller than the case where the existing pile is moved, and the labor and cost for removing the existing pile can be greatly reduced.
[0060]
According to the second aspect of the present invention, the same effect as that of the first aspect of the invention can be obtained, and the extraction portion is moved above the ground by a predetermined length, and the extraction portion is moved from the upper end by this predetermined length. By repeatedly cutting and shortening in the transverse direction at the lower position and moving the extraction portion above the ground, the stroke of the machine for moving the extraction portion upward can be shortened.
Therefore, it is easy to remove the site where the existing pile should be removed even in a narrow place where the space above the existing pile is restricted.
[0061]
According to the invention described in claim 3, while the same effect as that of the invention described in claim 1 or 2 can be obtained, the drawing portion is cut in the longitudinal direction and divided into a plurality of drawing blocks. The weight of the block and the frictional force between it and the ground on the peripheral surface are approximately a fraction of the above-mentioned number of divisions with respect to the weight of the entire extraction part and the frictional force between this and the ground on the peripheral surface. In other words, the force required to move these drawing blocks sequentially above the ground G is approximately one-fifth of the above-mentioned number of divisions with respect to the force required to move the entire drawing portion simultaneously above the ground. . Since each drawing block is sequentially moved above the ground, a machine (pulling device) for moving these drawing blocks has an output capable of moving one of the drawing blocks upward. It is possible to move the extraction part to the upper side of the ground using a small machine as compared with the case where the entire extraction part is moved upward at the same time.
This effect is conspicuous when removing cast-in-place concrete piles having a relatively large diameter.
[0062]
According to the invention described in claim 4, the same effect as in the invention described in any one of claims 1 to 3 can be obtained, and the remaining portion can be formed inside the existing pile from the upper end of the existing pile. A through-hole that reaches partway is drilled, a rod is inserted into this through-hole, its tip is brought into contact with the bottom of the through-hole in the remaining part, and the pulling part is placed above the ground while bearing a reaction force on this rod. Therefore, when moving the extraction part above the ground, it is not necessary to secure a support surface for bearing a reaction force on the side peripheral part of the existing pile on the surface of the ground.
Therefore, even in a narrow place where there is no room for work on the side peripheral part of the existing pile, the extraction part can be moved above the ground.
[0063]
According to the invention described in claim 5, the same effect as that of the invention described in claim 3 can be obtained, and at least one other drawing block can be placed on the ground while causing at least one drawing block to bear a reaction force. Repeatedly moving upward, each extraction block is moved sequentially above the ground, so when pulling each extraction block, the support surface for bearing the reaction force is the side periphery of the existing pile on the surface of the ground, etc. There is no need to secure it.
Therefore, even in a narrow place where there is no room for work on the side peripheral part of the existing pile, the extraction part can be moved above the ground.
[0064]
According to the invention described in claim 6, the same effect as that of any one of the inventions described in claims 1 to 5 can be obtained, and when the extraction portion is moved above the ground, the extraction portion and its Since the frictional force with the ground around the side is stopped or reduced, the output of the machine that moves the extraction part above the ground G can be small, and the energy used can also be reduced.
[0065]
According to the seventh aspect of the present invention, the same effect as that of any one of the first to sixth aspects of the present invention can be obtained, and the cavity formed by moving the drawing portion upward is filled. Since the material is filled, the drawing portion moved upward from the ground is placed and supported on the filling material. Therefore, the extraction portion can be stabilized at a certain height in the ground.
[0066]
According to the eighth aspect of the present invention, the same effects as those of the first aspect of the present invention can be obtained, and the pull-out portions 11 and 21 can be moved above the ground G to a desired height h1. , H2 and then the frictional force between the extraction parts 11 and 21 and the ground G on the side thereof is set to a predetermined value or more, so that the extraction parts 11 and 21 moved above the ground G are This frictional force stabilizes the ground G at a certain height.
[0067]
According to the ninth aspect of the invention, the same effect as that of the fourth aspect of the invention can be obtained.
[0068]
According to the invention described in claim 10, the same effect as that of the invention described in claim 5 can be obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a procedure of an example of a method for removing an existing pile according to the present invention.
FIG. 2 is a diagram showing a procedure for reducing the frictional force between the extraction portion and the ground around the side in the above example.
FIG. 3 is a longitudinal sectional view showing the procedure of another example of the method for removing an existing pile according to the present invention.
FIG. 4 is a longitudinal sectional view showing details of an upper end of a pulling portion and a pulling device in the above example.
5 is an AA arrow view in FIG. 4;
6 is a cross-sectional view taken along the line BB in FIG.
FIG. 7 is a longitudinal sectional view showing a rising state of the drawing block in the above example.
[Explanation of symbols]
1, 2 Existing pile 1H Through holes 1R, 2R Positions 1Rb, 2Rb (of the existing pile) to be removed 1h, 2h (lower part) ascending height 3 Rod 4 Filler (extracted part) High fluidity soil)
5,9 Existing pile pulling device 11,21 Pulling part 12,22 Remaining part 21A-21H Pulling block 51 Rod push / pull means (jack)
52 Pull-out part push / pull means (jack)
53 Arm 53a Clamping means (chuck)
91-94 Block push / pull means (jack)
G Ground V Cavity

Claims

It is a method for removing an existing pile that moves and removes at least part of the length direction of the existing pile upward,
The existing pile is cut in the transverse direction at the position of the lower end of the part to be removed, and the existing pile is divided into a drawing portion and a remaining portion, and the drawing portion is moved above the ground by a desired height. The removal method of the existing pile characterized by this.

In the removal method of the existing pile of Claim 1,
Move the extraction part above the ground by repeatedly moving the extraction part above the ground by a predetermined length, cutting the extraction part in the transverse direction at a position below the upper end by the predetermined length, and shortening it. A method for removing an existing pile, characterized in that

In the removal method of the existing pile of Claim 1 or 2,
A method for removing an existing pile, wherein the drawing portion is cut in a longitudinal direction to divide the drawing portion into a plurality of drawing blocks, and each drawing block is sequentially moved above the ground.

In the removal method of the existing pile as described in any one of Claims 1-3,
A through-hole that reaches from the upper end of the existing pile to the middle of the remaining portion is drilled in the existing pile, a rod is inserted into the through-hole, and a tip of the through-hole is formed on the bottom surface of the through-hole in the remaining portion. A method for removing an existing pile, wherein the pulling portion is moved above the ground while abutting and causing a reaction force to be applied to the rod.

In the removal method of the existing pile of Claim 3,
Existing pulling blocks are moved sequentially above the ground by repeatedly moving at least one other pulling block above the ground while applying a reaction force to at least one of the pulling blocks. Pile removal method.

In the removal method of the existing pile as described in any one of Claims 1-5,
A method for removing an existing pile, characterized in that, when the pulling portion is moved above the ground, the frictional force between the pulling portion and the ground around the pulling portion is stopped or reduced.

In the removal method of the existing pile as described in any one of Claims 1-6,
A method for removing an existing pile, wherein a filling material is packed into a cavity formed by moving the extraction portion upward.

In the removal method of the existing pile as described in any one of Claims 1-7,
A method for removing an existing pile, wherein the pulling portion is moved upward by a desired height above the ground, and then the frictional force between the pulling portion and the ground around the side is increased.

A lifting device for an existing pile used in the method for removing an existing pile according to claim 4,
Rod pushing and pulling means capable of pushing and pulling the rod;
A plurality of pull-out portion push-pull means attached to the rod push-pull means and surrounding the side of the rod push-pull means at a predetermined interval;
An arm that is pushed and pulled in parallel with the rod by each pulling portion pushing and pulling means;
A lifting device for an existing pile, comprising: clamping means attached to the tip of each of the arms and capable of clamping the side surface of the extraction portion.

A lifting device for an existing pile used in the method for removing an existing pile according to claim 5,
Two or more block pushing and pulling means capable of pushing and pulling each drawing block are provided,
Each of the block pushing and pulling means is fixed to each other so that the drawing blocks connected to each other can be pushed and pulled at the same time by mutually independent operations.