JP4958028B2 - Construction method of pile hole rooting layer, foundation pile construction management device, foundation pile construction management method - Google Patents

Description

【００５０】
なお、試験の各測定値の絶対値は、測定タイミング、測定地点ごとの地質強度等により本質的に差異があるため、測定値のバラツキで工法比較するのが適切である。一軸圧縮強度の測定値は、２２Ｎ／ｍｍ^２前後で、電気比抵抗の測定値は、５Ωｍ 前後であった。
【００５１】
３．試験結果のまとめ
(a) 新仕様（Case２、Case３）の圧縮強度バラツキは、１０％以下で安定しており、従来の仕様（Case１、Case４）に比べ、1/2 以下に改善されている。更に、新仕様同士の電気比抵抗でのミクロな比較では、仕様２がより均質であることが分る。
従って、セメントミルクを撹拌しながら吐出し、少なくとも２回上下させる方法に効果があることが分る。
(b) 掘削土に強度上良くないシルトなどが混入している場合には、底部で（撹拌せずに）セメントミルクを吐出して拡大根固め層より上方（軸部）に押し上げることが望ましいので、この視点からも仕様２が望ましいことが言える。
(c) 今回、比較はしていないが、本試験の結果から、根固め層の掘削とセメントミルクの注入を併行実施する施工方法では、底部でセメントミルクを吐出できないために、新仕様に比べ層内のセメントミルクがバラツキ、根固め層の性能が劣ると判断される。
【００５２】
(d) 撹拌方法としては、上記のような仕様で、撹拌混合した場合、撹拌装置として掘削ヘッド２をそのまま使用したので、掘削ロッド１の交換による時間的ロスが無く、簡便で、かつ撹拌に最も寄与する（撹拌時に外周側に位置する）掘削アーム６の先端部５７を面積を大きく形成したので、杭穴の周辺部での撹拌効率が良く、更に粉砕不十分な掘削土があったとしても、更により細かく粉砕できるので、均一な混合が可能である。また、掘削時の１．５〜２．０倍の高速の回転をするので、更に撹拌効率が良い。
【００５３】
また、撹拌動力源としても掘削時に使用したオーガーマシンを使用したので、その土質に適合した撹拌動力源として機能すると共に、掘削時の２倍の回転数まで回転した場合であっても確実かつ安定な撹拌混合が可能になった。
【００５４】
従って、その杭穴掘削時の掘削ヘッド２、掘削ロッド１、オーガーマシン等の掘削装置をそのまま使用して、均質な撹拌混合ができる経済的にも優れた工法が確立できた。
【００５５】
【実施例１】
図１乃至図１０に基づきこの発明の実施例を説明する。
【００５６】
（１）杭穴軸部８の掘削
【００５７】
施工場所において、掘削機を据え付け、所定の杭埋設位置で、先端に掘削ヘッド２を有する掘削ロッド１で、杭穴７を掘削する（図１（ａ）（ｂ））。前記掘削ロッド１は、中間部に撹拌バー３、３及び杭穴内壁を均す練付ドラム４、４を設けてある。また、杭穴７の掘削に当たり、掘削機のオペレータ室において、掘削状況（各種情報）が表示装置（各種ディスプレイ装置）に画面表示される（図４）。
【００５８】
杭穴７の掘削径は、埋設予定の既製杭の節部径（７５０φ）＋３０ｍｍを確保した杭穴軸部８とする。途中、掘削ヘッド２に設けられた吐出口５より適量の水を注水しながら掘削し、その掘削土を撹拌バー３、３で充分撹拌し、泥土化し、練付ドラム４、４で内壁７ａに練り付けし、深さ４６．５ｍまで掘削する。
【００５９】
事前に、施工地盤において得られている標準貫入試験による測定結果が「Ｎ値表示欄２７」に表示され（図５）、この測定結果に基づき、掘削深度とその深度でのＮ値を表示しながら、「積算電流値表示欄３０」で掘削負荷電流の蓄積値（記録値）を並列表示し（図８）、両者を比較・確認しながら掘削する。もし、予定深さでの支持地盤における該記録値が適合しない場合には掘削深度を調整する。また、同時に、「流量・ヘッド位置表示欄２８」にその時刻での深度と掘削中の注水量（Ａ１）も一緒に表示・記録される（図６）ので、確認・調整する。
【００６０】
表示装置における「積算電流値表示欄３０」の掘削負荷電流の蓄積値としての記録値は、貫入試験のＮ値（打ち込み寸法３０ｃｍ）と適合させるために、記録値としての掘削負荷電流の蓄積値の幅を、所定深度毎に、掘削寸法を３０〜５０ｃｍの範囲で適当に可変・設定する。ここでは、深度５０ｃｍ毎に５０ｃｍ幅の負荷電流を蓄積して表示した結果、貫入試験のＮ値の変化と相対的にほぼ合致した傾向の値が得られることを確認した（図８）。従って、記録値は５０ｃｍ幅の負荷電流蓄積値でＡ・ｓｅｃ（アンペア・秒）で表示してある。
【００６１】
また、５０ｃｍ毎に負荷電流値を表示することによって、通常の標準貫入試験の１ｍ間隔の測定よりも精度を約２倍に向上させることができる。
【００６２】
すなわち、標準貫入試験におけるＮ値の測定が、重量６３．５ｋｇのサンプラーを深度方向で土層範囲３０ｃｍ打ち込む打撃数を示しており、本手法はその打撃前後に利用されている土層範囲５０ｃｍ毎にその地盤の強度を仕事量に比例する数値で表示することができるようになっている。
【００６３】
そこで、通常の掘削機の電源が定電圧で制御されていることを利用し、さらに、この掘削機の掘削時の負荷電流が地盤強度に比例することを前提として、標準貫入試験で利用する土層幅と略同一範囲（３０〜５０ｃｍ）でこの負荷電流を蓄積し、負荷電流の時間積（アンペア・秒）すなわち地盤強度と比例する仕事量単位でそのまま簡便に表示をすることにより、その現場の各掘削穴毎にその掘削地点での地盤強度とＮ値とを対比して、根固め層の築造位置が確かな工事ができるようにしたものである。ここで、蓄積土層幅は、土質のバラツキが多い、あるいは土層幅の広さなど必要により３０〜５０ｃｍの範囲で調整するのが標準貫入試験での測定土層幅寸法と近似しており整合性が良い。
【００６４】
即ち、このように掘削機の負荷電流の時間積を表示する構成としたので、杭穴掘削時の掘削電流に関して、標準貫入試験のＮ値測定で使用される土層巾とほぼ同一の範囲（３０〜５０ｃｍ）で連続して蓄積して、その蓄積完了時に、その深度毎に記録・表示するので、標準貫入試験の場合における、「深度毎（５０ｃｍ毎）」の打撃回数の表示の当該「深度毎」にも対応できるようにしたものである。
【００６５】
従って、施工現場の地盤強度に関して、数少ない標準貫入試験データを補い、施工現場全体の精度の高い地盤状況が把握できると共に、各杭基礎ごとにより適切な支持層を設定でき、より安全で確かな基礎を容易に提供することができる。
【００６６】
その後、掘削土を撹拌しながら掘削ヘッド２を上下に反復移動させ、杭穴軸部８を築造する（図１（ｂ））。また、支持地盤は、砂質土で、Ｎ値は３０以上であった。この掘削結果（掘削深度等）に基づき、各杭穴毎に「基本データ表示欄２６」の設定値を変更させることも可能である。
【００６７】
（２）杭穴７の拡大根固め部９の掘削
【００６８】
次に、掘削径を拡大し、吐出口５から注水しながら、拡大径１１００ｍｍで、深さ２．５ｍの拡大根固め部９を築造し、掘削土を撹拌しながら上下２回反復させる（図１（ｃ））。
【００６９】
表示装置における「流量・ヘッド位置表示欄２８」で、表示記録としては、掘削深さと注水量を確認・調整する（図６）。
【００７０】
（３）拡大根固め部９でのセメントミルク注入（根固め層の形成）
【００７１】
本発明の方法を利用して、セメントミルクを注入し、均質な根固め層（ソイルセメント層）１３を形成する。
【００７２】
根固め用のセメントミルクは、セメント（ＪＡＳＳ４ ２節 ４．２．１による）２５９０ｋｇ、水１５５４ｋｇで、練上がり２．３８ｍ^３とする。
【００７３】
先ず、掘削ヘッド２の吐出口５を拡大根固め部９の中央の底１０付近に保持し、根固め液（前記の混合比のセメントミルク）全部の使用量（２．３８ｍ^３）の 1/3 をその位置のまま、掘削ヘッド２で撹拌しながら、毎分約２００リットルで吐出する（１回目の吐出。図１（ｃ）、図３（ｂ））。
【００７４】
次に、根固め液を同様に吐出しながら掘削ヘッド２を最上部まで撹拌しながら引き上げる（図１（ｄ））。その間に根固め液全使用量の 1/3を吐出する（２回目の吐出。図３（ｂ））。
【００７５】
次に、根固め液を同様に吐出しながら、掘削ヘッド２を上下２回往復させ、底１０に到達し終了するまでの間に根固め液使用量の残量の 1/3すなわち、規格以上のセメントミルクを注入しながら、掘削土と撹拌及び混合を行いソイルセメント層を形成する（３回目の吐出。図３（ｂ））。
【００７６】
表示装置の「流量・ヘッド位置表示欄２８」には、その時刻での掘削ヘッド２の位置（深度ｍ）、セメントミルク流量（ｍ^３/ h ）を表示・記録しており（図６）、表示切替により掘削ヘッド２の位置と根固め液注入量（ｍ^３）のみの拡大表示を選択すれば、容易に根固め液注入量の対比・調整ができ管理精度を向上させることができ、また、「根固め液注入量表示欄３１」で深度毎の根固め液注入量が確認できる（図９）。例えば、注入量不足時は再注入による修正をする。また、各施工条件、実績記録値が対比記録されており、施工後においても工事の証明資料としても利用できる。
【００７７】
（４）杭穴軸部８でのセメントミルク注入（ソイルセメント層形成）
【００７８】
杭穴軸部用のセメントミルクは、根固め液と調合比は同じであるが、杭周固定液（周辺固定液）とも言う。セメントミルクの吐出量を毎分１００リットルで注入し、注入総量は２．２２ｍ^３以上とする（「基本データ表示欄２６」図４）。
【００７９】
先ず、拡大根固め部９の上端部１５から吐出開始し、撹拌しながら深さ３０ｍまで掘削ヘッド（注入口）を上下１往復させ、次に、深さ１２ｍまで同様に吐出・撹拌しながら掘削ヘッド２を上下１往復させ、次に、深さ２ｍ まで同様に吐出・撹拌しながら掘削ヘッド２を上下１往復させ、最後に杭穴口１２まで同様に吐出・撹拌しながら掘削ヘッド２を上下往復させ注入を完了させる（図２（ａ）（ｂ））。このようにして、杭穴軸部８内に杭周固定液層（ソイルセメント層）１６を形成する。
【００８０】
表示装置の「杭周固定液注入量表示欄３２」には、その時刻での掘削ヘッド２の位置（深度ｍ）とセメントミルク流量（ｍ^３／ｈ）を表示・記録しており、表示切替により掘削ヘッド２位置と注入量（ｍ^３／ｈ）のみの拡大表示を選択すれば、容易にセメントミルクの注入が手順通り実施されたか確認できる（図６、図１０）。
【００８１】
従って、各基礎杭の施工途中で、セメントミルク注入の補充などの修正ができ、また、所定の手順通りに施工された証明とすることもできる。
【００８２】
尚、「流量・ヘッド位置表示欄」（図６）において、グラフＡが時間当たりの吐出量（単位ｍ^３／ｈ）が縦軸として横軸を施工所要時間として表示され、０〜３７分までは吐出口５から水を吐出して（Ａ１）、３７分〜４６分までは根固め液を吐出し(Ａ２)、４６分以降は周辺固定液を吐出している（Ａ３）ことを示す。また、グラフＢで、吐出口５から吐出される水・根固め液・周辺固定液の総流量が逐次表示される。また、グラフＣでは、縦軸を地上からの深度（ｍ）に設定し、横軸を施工所要時間とし、掘削ヘッド２の位置が表示される。
【００８３】
（５）既製杭２０、２２の埋設
【００８４】
掘削ロッド１から掘削ヘッド２を取り外して、先ず、「ＢＦ６０７５―５ｍ」既製杭２０（軸径：φ６００、節径：φ７５０、節杭）（「ＢＦ」は三谷セキサン株式会社の節杭の商標。以下、同じ。）をロッド１に装着し、回転させながらソイルセメントの充填された杭穴７へ沈設する。次に、「ＳＣφ６００−１４ｍ」既製杭２２を連結・沈設し、以降、「ＳＣφ６００−１５ｍ」既製杭２２、「ＳＣφ６００−１５ｍ」既製杭２２と順次同様に連結し、連結杭の先端の「ＢＦ６０７５―５ｍ」既製杭２０の先端２１を、拡大根固め層１３の底１４から約５０ｃｍの位置に押し込み埋設させ、既製杭２０、２２の埋設を完了させる（図２（ｃ）（ｄ））。ソイルセメントが固化後に、杭穴７内で既製杭２０、２２と根固め層１３及び杭周固定液層１６（ソイルセメント）とが一体となった基礎杭２４を構築する。
【００８５】
また、表示装置の「杭先端位置表示欄２９」には、既製杭２０、２２の埋設時間が記録されると共に既製杭２０の先端２１の位置が記録され、その施工結果を既製杭２０、２２を埋設しながら、また各基礎杭２４施工毎に確認できるとともに、施工内容の保証データとしても利用できる（図４、図７）。
【００８６】
（６）完成した基礎杭２４の評価
【００８７】
(a) 最大荷重
根固め部（既製杭２０と根固め層１３）上部の載荷試験における節径の０．１Ｄ（Ｄは節杭軸部の径）沈下時の荷重は、７０００ｋＮ以上が得られ、高支持力の品質が造成されていることが確認できた。すなわち、通常の基礎杭の２倍以上が得られた。
【００８８】
(b) 根固め部の健全性
根固め部（既製杭２０と根固め層１３）を掘り出し、その外観および形状寸法を調査した結果、クラックや大きな欠損箇所はなく、掘削所定径以上の根固め部が造成されていることが確認された。
【００８９】
（７）表示記録の効果
【００９０】
図４（図５〜図１０）の様式での表示装置に各種データが表示、出力が可能である。また、表示装置の表示欄の上端部の「基本データ表示欄２６」には、予め「使用する既製杭の仕様」「掘削長」「杭天端位置」「セメントミルクの配合」「根固め液注入量及び杭周固定液注入量」が表示される（図４）。「根固め液注入量及び杭周固定液注入量」は規格量（設計値）が施工前に表示されると共に、施工中に実際の使用量が逐次表示される。
【００９１】
(a) 掘削穴の深度、掘削負荷電流の蓄積値（Ｎ値代用特性記録値）、流量計の実計測値を対比表示するので、根固め部等の施工状況をリアルタイムで確認・管理できる（図５、図６、図８〜図１０）。
(b) 地盤強度をＮ値の近似代用特性（負荷電流蓄積値）で確認掘削できるので適正な支持層が設定できる（図５、図８）。
(c) セメントミルクの注入、撹拌の状況が経過時間と深度とで併行確認、管理ができる。また、杭穴の実際の掘削データ（支持層位置等）に基づき、セメントミルクの注入位置、量等の設定条件等を修正できる。
(d) 施工が確実に実施されたか否かの総合的品質証明資料となり、従来に比べ、より緻密な施工報告書の実記録として活用できる（図４）。
【００９２】
【実施例２】
次にこの発明の他の実施例を説明する。
【００９３】
（１）杭打ち機４２の基本的構成
【００９４】
この発明の実施に使用する杭打機４２には、自走できるベース３４の一側にリーダー３５が起立されており、このリーダー３５の上先端に設けたトップシーブ３６を介してワイヤ３７が昇降自在に吊り下げられ、ワイヤ３７の先端にオーガマシン３８が接続されている。ワイヤー３７の基端は、ベース３４上に取り付けられた巻出し装置４１を介して、巻出し用のモータ（図示していない）の軸に取り付けてある。
【００９５】
オーガマシン３８の基端には駆動モータ４０を収納したボックス３９が取付けられており、このボックス３９の下部には駆動モータ４０で回転駆動される掘削ロッド１が垂下されている。掘削ロッド１は、前記実施例１と同様で、下端に掘削ヘッド２が取り付けられていると共に、掘削ロッド１には所定間隔を置いて軸方向に沿って複数の撹拌棒３、３と練付ドラム４、４が配設されている。
【００９６】
また、図中４３は、オーガマシン３８の駆動モータ４０、ワイヤー巻出し用のモータ等に電気を供給する発電機である（図１１）。発電機４３から供給される電気は杭打機４２に設けられている配電盤４３ａに送られ、そこからオーガマシン３８等に配電される。
【００９７】
（２）施工管理装置の構成
【００９８】
次にこの装置の制御系統を説明する。
【００９９】
(a) センサー類
杭打ち機４２に設けられている配電盤４３ａ又は発電機４３にはオーガマシン３８の駆動モータ４０の負荷電流を測定する負荷電流計４４が接続されている。負荷電流計４４からのデータは、オペレータ室内のアンプボックス５０に入力される（図１２）。
【０１００】
また、杭打機４２のリーダー３５の下端部にロータリーエンコーダからなる深度計４５が設置され（図１１）、深度計測用ワイヤ３７ａが深度計４５を介してリーダー３５に沿ってオーガマシン３８に取付けられている。これによって、オーガマシン３８の降下量、すなわち掘削深度を検知する。深度計４５からのデータはオペレータ室内のアンプボックス５０に入力される（図１２）。尚、深度計４５はロータリーエンコーダに限らず、他の計測具とすることもでき、またオーガマシン３８に取付けられているワイヤ３７の繰り出し量から深度を計測してもよい。
【０１０１】
また、ここでは深度計４５をリーダー３５の下端部としたが、リーダー３５のどの位置に設けてもよく、またオーガマシン３８に設置してもよい。
【０１０２】
また、構築現場内（又は構築現場に近接して）に、水やセメントミルク等の硬化性材料を生成して送り出すプラント４６が設置され、プラント４６と杭打ち機４２とは耐圧ホース４７でつながっている。耐圧ホース４７は、掘削ロッド１を通って掘削ヘッド２の吐出口５から吐出できるようにオーガマシン３８に連結されている。この耐圧ホース４７の中間部、例えば、ベース３４の杭打ち機４２側に、吐出量を検知するための流量計４８が設置されている（図１１）。流量計４８のデータは、オペレータ室内のアンプボックス５０に入力される（図１２）。
【０１０３】
また、オーガマシン３８の下降開始（深度計４５の作動）に対応して、掘削開始からの施工所要時間（ｍｉｎ．）が計測される。
【０１０４】
(b) 管理装置
アンプボックス５０で、まとめられた各センサー４４、４５、４８からのデータは、パーソナルコンピュータ（以下、ＰＣ）５１で制御、演算、処理されて画面（データー表示装置）５２に表示されるとともに、ＰＣ５１からの操作により、印刷機５３に紙出力も可能である。また、負荷電流計４４、深度計４５及び流量計４８から得られるデータは、一般にアナログ信号であるため、アンプボックス５０内のＡ／Ｄ変換器によってデジタル信号に変換して、ＰＣ５１に送られる。
【０１０５】
ここで、オペレータ室５５内とは、プラント内、現場施工管理者等の常駐事務所内等の現場敷地内の施設や、あるいは杭打ち機の操作室内、または現場外の独立した施設内に配置される。また、オペレータ室は、雨天等を考慮して屋根のある施設（例えば、仮設建物、仮設テント等）が望ましいが、作動に支障が無ければ、屋根の有無は問わない。
【０１０６】
また、アンプボックス５０でまとめられて、ＰＣ５１で処理されたデータは、以下のように画面５２に、各表示欄２７〜３２毎に分割して表示される（図４）。また、各表示欄２７〜３２を単独で切り替えて拡大表示することもできる（図５〜図１０）。また、複数欄を組み合わせて並べて表示することもできる（図示していない）。
【０１０７】
即ち、深度計４５からのデータは処理され、地面１８からの杭先端位置（ｍ）を縦軸に、杭挿入所要時間（ｍｉｎ．）を横軸にして、対応させたグラフが、画面５２の「杭先端位置表示欄２９」に表示される（図７、図４）。
【０１０８】
また、深度計４５及び負荷電流計４４からのデータは、一定掘削範囲（例えば、深さ３０ｃｍ毎）に要した駆動モータ４０の負荷電流を、該掘削範囲に要した時間で積算し、蓄積した積算電流記録値（Ａｍｐ×ｓｅｃ）として処理される。深度計４５からのデータは、別途処理され地面１８からの深度（ｍ）を縦軸に、前記積算電流記録値を横軸にして、対応してグラフ化され、画面５２の「積算電流値表示欄３０」に表示される（図８、図４）。
【０１０９】
また、杭穴の実際の掘削データ（支持層位置等）に基づき、各杭穴毎に「基本データ表示欄２６」の設定値も必要により修正され、表示される。
【０１１０】
また、流量計４８からの根固め液の注入量（ｍ^３）のデータを横軸に、深度計４５からのデータは、地面１８からの深度（ｍ）として縦軸に設定し、対応してグラフ化され、画面５２の「根固め液注入量表示欄３１」に表示される。この際、各深度毎の「設計時の根固め液の規定量」が、同時に表示され、掘削データにより見直しされた設計量と実際の注入量とを比較できる（図９、図４）。この場合、各深度毎に実際の注入量が設計量に達した場合に、画面５２に案内表示を点滅させ、あるいは警告を促す音を発するようにすることもできる。
【０１１１】
また、同様に、流量計４８からの杭周固定液の注入量（ｍ^３）のデータを横軸に、深度計４５からのデータは、地面１８からの深度（ｍ）として縦軸に設定し、対応してグラフ化され、画面５２の「杭周固定液注入量表示欄３２」に表示される。この際、各深度毎の「設計時の杭周固定液の規定量」が、同時に表示され、設計量と実際の注入量とを比較できる（図１０、図４）。この場合、各深度毎に実際の注入量が設計量に達した場合に、画面５２に案内表示を点滅させ、あるいは了解音を発するようにすることもできる。
【０１１２】
また、予め標準貫入試験時のボーリングデータ（Ｎ値、土質名等）をＰＣ５１に入力しておく。深度計４５からの受ける地面１８からの深度（ｍ）のデータを縦軸に、各深度（ｍ）毎の「Ｎ値」を横軸にして、対応させてグラフ化され、画面５２の「Ｎ値表示欄２７」に表示される（図５、図４）。この場合、Ｎ値以外の他のボーリングデータ（土質名等）を各深度（ｍ）毎に、Ｎ値に対応させて同時に表示することもできる（図示していない）。
【０１１３】
また、施工開始からの所要時間（ｍｉｎ．）を横軸として、縦軸に、流量計４８から「掘削用の水、根固め液又は杭周固定液」の時間当たりの流量（ｍ^３／ｈ）を表示する。また、同じく縦軸に、流量計４８から吐出物の総流量（累積流量。ｍ^３）を同時に表示する。また、同じく縦軸に、深度計４５から得られる地面１８からの「ヘッドの位置（ｍ）」を同時に表示する。所要時間（ｍｉｎ．）を共通の横軸とした３つのグラフが、画面５２の「流量・ヘッド位置表示欄２８」に、同時に表示される（図６、図４）。
【０１１４】
以上のような情報処理機能（演算、制御）、画面５２、内蔵又は外付けの記憶手段を持った「ＰＣ５１」と「印刷機５３」、深度計４５、流量計４８、負荷電流計４４からなるセンサー類を接続した「アンプボックス５０」と、ＰＣ５１、アンプボックス５０、印刷機５３に定格電源を供給する「電源装置（例えば、発電機５４、蓄電器など）」により、この発明の施工管理装置を構成する。
【０１１５】
また、深度計４５、流量計４８、電流検出器４４からなるセンサー類を接続した「アンプボックス５０」に無線送信アンテナを取付け、遠隔地（例えば施工現場の事務所内）に設置したＰＣ５１に無線受信アンテナを取付け、アンプボックス５０に収集される種々のデータを無線で送受信することもできる（図示していない）。このように、施工管理データの記憶、制御装置類を施工中の場所以外に設置するによって、施工現場の塵、土泥飛散や雨天等、また施工機械の震動による破損トラブルから隔離され、施工管理情報を安定して利用できる。
【０１１６】
また、インターネット等を利用することにより、施工現場外から施工情報を随時取得し、施工進捗管理等に使用することが可能である。
【０１１７】
【実施例３】
次に、本施工管理装置を使用した施工管理方法について述べる（図１３）。
【０１１８】
（１） 杭施工位置での、「使用杭（ここでは上杭、中杭、下杭を使用し、各杭の種類外径、長さ等）」「掘削孔の深さ（ＧＬ（地面１８）からの深さ」「杭天端（ＧＬ（地面１８）からの位置）」「（１バッチ毎の）セメントミルク配合（ここではセメント７５０ｋｇ、水４５０ｋｇ、錬り上り量０．６９ｍ^３）」「根固め液注入量の規格値（ここでは２．３８ｍ^３）」「杭周固定液注入量の規格値（ここでは、２．２２ｍ^３）」を入力する。これらのデータは、画面５２の上部の「基本データ表示欄２６」に表示される（図４）。尚、「根固め液注入量」「杭周固定液注入量」は掘削データにより見直しされた規格値に並列して、実際の注入量が逐次表示される。
【０１１９】
前記規格値は、例えば、
杭軸部径 ６００ｍｍ
突起部径 ７５０ｍｍ
杭穴軸部径 ７８０ｍｍ
杭穴拡底部径 １１００ｍｍ
の場合に、
根固め液の充填量は、１０ｃｍ毎に０.０６１ｍ^３、
杭周固定液の充填量は、 １ｍ毎に０.０４７８ｍ^３、
程度となる。
【０１２０】
（２） また、予め入手しているボーリングデータ（Ｎ値、土質名等）をＰＣ５１に入力し、ボーリングデータの深度と掘削深度を対応させ、深度を基準とした積算電流値が「積算電流値表示欄３０」に表示される（図８、図４）。
【０１２１】
このとき、施工情報（例えば、施工法、掘削深度、掘削径、硬化性材料の注入量等）、施工機械情報（例えば、低速ベース電流値(Ａｍｐ)、低速回転数(回／分)、高速ベース電流値(Ａｍｐ)、高速回転数(回／分)等）などを入力しておく。これらのデータも切り替えて画面５２に表示することもできる（図示していない）。
【０１２２】
（３） 掘削ロッド１を搭載した杭打ち機４２を所望の杭打ち位置に移動し（図１１）、駆動モータ４０で掘削ロッド１を正回転（例えば時計周り）させつつ、ワイヤ３７を介して、リーダー３５に沿って、オーガマシン３８を徐々に降下させる。掘削ロッド１の先端には、本体６ａと２本の掘削アーム６、６とからなる掘削ヘッド２が取付けられており、掘削ロッド１の回転と共に２本の掘削アーム６、６が開き、掘削アーム６、６先端の掘削刃と本体６ａ下端部の掘削刃によって杭穴軸部の掘削を行う（図１１、図１５（ｂ））。
【０１２３】
この際、オーガマシン３８の下降量は、掘削深度として、深度計４５で検出されており、掘削ヘッド１の掘削刃が地面と接した状態で深度を「０（ゼロ）」とするように初期設定を行う（図１５（ａ））。また、駆動モータ４０の負荷電流は、負荷電流計４４で連続的に検出されており、無負荷時の測定電流が初期電流として設定される。
【０１２４】
（４） オーガマシン３８を引き続き下降させることによって、掘削ヘッド１の先端より水等を吐出しながら地盤が掘削され、撹拌バー３、３で掘削土を撹拌しつつ、練付ドラム４、４で杭穴７の内壁７ａに練付ける。このとき、吐出する水の量は流量計４８によって、各深度毎の吐出量がグラフ化されて、ＰＣ５１の画面５２上に表示される。
【０１２５】
掘削に際して、地盤の固さにより、駆動モータ４０に対する負荷が変わり、これに応じて負荷電流が変化する。これによって、所定掘削間隔（例えば５０ｃｍ毎）ごとに負荷電流値を蓄積し、該掘削間隔に要した掘削時間とを演算処理し、積算電流値として、予め入力されているボーリングデータのＮ値、土質名と共に深度を基準として掘削と同時に表示される（図５、図８、図４）。積算電流値は、Ｎ値と近似的な曲線を描くため、仮に掘削中に積算電流値がＮ値と異なる曲線を描いた場合、ボーリングと異なる地盤が存在することが確認でき、施工中に適切な対応をとることができる。
【０１２６】
（５） 引き続き掘削を続行し、所定強度の支持層に到達したことをＰＣの画面５２に表示されているＮ値と積算電流値とによって確認し（図５、図８）、支持層を所定深度掘削した後、掘削ロッド１を逆回転させて、掘削ロッド１を引上げながら杭穴拡大根固め部９の掘削を行う。拡大根固め部９の掘削時には、掘削ロッド１を逆回転させ、掘削ヘッド２の掘削アーム６、６を通常掘削時とは逆に揺動して拡開し、拡大掘削状態となる。杭穴の拡大根固め部は所定高さ（例えば、２５０ｃｍ）設ける必要があるが、深度計４５によって掘削ヘッド２の位置がＰＣの画面５２に表示されているため（図６、図４）、所定高さの拡大根固め部９の掘削を行うことができる。
【０１２７】
（６） 所定大きさの杭穴７の拡大根固め部９を形成した後、バルブ（図示していない）を切り替えて、吐出物を水からセメントミルクに切り替える。プラント４６から耐圧ホース４７を通して、掘削ヘッド２の吐出口５からセメントミルクが杭穴内に供給される。
【０１２８】
（７） ＰＣ５１の画面５２の「基本データー表示欄２６」「根固め液注入量表示欄３１」「杭周固定液注入量表示欄３２」には、先に入力した根固液、杭周固定液の規格値が表示される。また、所定深度間隔毎の充填量はグラフ化されて、画面５２の「流量・ヘッド位置表示欄２８」「積算電流値表示欄３０」「根固め液注入量表示欄３１」「杭周固定液注入量表示欄３２」に表示し（図６、図９、図１０、図４）、規格値以上のセメントミルクが注入されているかどうかを目視で、確認しながら施工を行う。また、同時に根固め液、杭周固定液の実際の使用量が、規格値と共に並列して「基本データー表示欄２６」表示される（図４）。
【０１２９】
（８） 先ず、杭穴７の拡大根固め部９内に根固液としてのセメントミルク（固化強度２０Ｎ／ｍｍ^２）を注入する。所定深度間隔毎の充填量を画面５２で確認しながら、拡大根固め部９内において、掘削ロッド１（掘削ヘッド２）を逆回転させながら上下反復して、掘削土と撹拌・混合し、根固め層１３（ソイルセメント層。固化強度２０Ｎ／ｍｍ^２以上）を形成する。
【０１３０】
このとき、セメントミルク量が規格値を超えていない場合には、該当深度で、セメントミルクを再注入する。
【０１３１】
（９） 前記における根固め層１３の構築、即ち、杭穴７の拡大根固め部９内でのセメントミルクの注入は、根固め層１３内のソイルセメントの品質のばらつきを少なくするために、前記実施例１と同様に行うことが望ましい。
【０１３２】
即ち、杭穴７の掘削完了後、掘削ヘッド２を杭穴底１０に保持した状態で掘削ヘッド２で撹拌しながら、掘削ヘッド２下端の吐出口５から根固液としての全セメントミルク量の３分の１宛セメントミルクを吐出する。続いて、掘削ヘッド２で撹拌しながら、掘削ロッド１を杭穴７の拡大根固め部９の上端部１５付近まで上昇させながら全セメントミルク量の３分の１宛を吐出する。次に、掘削ヘッド２を拡大根固め部９内で（杭穴７の底１４と拡大根固め部９の上端部１５との間を）複数回昇降させながら、残りのセメントミルクの３分の１宛を吐出して、撹拌及び混合を行い、掘削ロッド１を引き上げて拡大根固め部９内にソイルセメント層からなる根固め層１３を形成する（図３（ｂ）、Case 2）。
【０１３３】
このような複雑な施工であっても、画面５２の「流量・ヘッド位置表示欄２８」「根固め液注入量表示欄３１」等で、根固め液（セメントミルク）、掘削ヘッド２の位置を目視により確認しながら行うことができ、細かい施工管理が極めて容易かつ確実にできる。
【０１３４】
（１０） また、他の望ましいセメントミルクの注入方法は、先ず、掘削ヘッド２の吐出口５を杭穴７の拡大根固め部９の底（構築予定の根固め層の底部）のほぼ中央に設置し、撹拌・吐出しながら拡大根固め部９内を上下２往復させて、上端部１５で注入を完了させる（図３（ｃ）、Case 3）。
【０１３５】
また、拡大根固め部９の底１０で掘削ヘッド２の吐出口５から全量のセメントミルクを注入して、拡大根固め部９内の掘削泥土を押し上げて、掘削泥土をセメントミルクと置換してセメントミルク層からなる拡大根固め層１３を形成することもできる（図３（ｄ）、Case 4）。
【０１３６】
（１１） 次に、拡大根固め部９内にセメントミルクを注入し、根固め層１３の構築が完了した後、掘削ロッド１を正回転に戻し、掘削ヘッド２を通常掘削状態にして、引き続き杭穴７の軸部８内に杭周固定液（固化強度２０Ｎ／ｍｍ^２）の注入を開始する。杭周固定液に関しても、根固液の注入と同様に、所定深度間隔毎の充填量を規格量とをＰＣ５１の画面５２の「流量・ヘッド位置表示欄２８」「杭周固定液注入量表示欄３２」で比較して確認しながら、杭穴７の軸部８内にソイルセメント層からなる杭周固定液層１６（固化強度２Ｎ／ｍｍ^２以上）を形成する。このとき規格充填量を満たしていない場合には、根固液と同様に該当深度に再注入を行う。
【０１３７】
（１２） 前記における杭穴７の軸部８内でのセメントミルクの注入方法、即ち杭周固定液層（ソイルセメント層）１６の形成についても、根固め層１３の上端部１５の位置より上方に、掘削長さに応じて、１又は複数の所定深度を決め、根固め層１３の上端部１５からセメントミルクの注入を開始し、その所定深度間ごとに往復して、掘削土と撹拌・混合しながら、杭周固定層１６を形成する。
【０１３８】
杭周固定液（セメントミルク）の充填量の管理については、杭穴７の軸部８の一定範囲（例えば１ｍ毎に）において、所定深度間隔毎に注入したセメントミルク量の平均値を算出し、該平均値が規格充填量を超えていれば、施工は適当とすることもできる。
【０１３９】
（１３） 続いて、セメントミルクを基準充填量以上充填した後、前記実施例１と同様に、上杭、中杭及び下杭とからなる既製杭を挿入し、基礎杭２４を構築する。
【０１４０】
掘削ロッド１から掘削ヘッド２を取り外して、回転キャップを取付け、先ず、「ＢＦ６０７５―５ｍ」既製杭（下杭）２０（軸径：φ６００、節径：φ７５０、節杭）（「ＢＦ」は三谷セキサン株式会社の節杭の商標。以下、同じ。）を回転キャップに装着し、回転させながらソイルセメントの充填された杭穴７へ沈設する。次に、「ＳＣφ６００−１４ｍ」既製杭（中杭）２２を連結・沈設し、以降、「ＳＣφ６００−１５ｍ」既製杭２２、「ＳＣφ６００−１５ｍ」既製杭（上杭）２２と順次同様に連結し、連結杭の先端の「ＢＦ６０７５―５ｍ」既製杭２０の先端２１を、拡大根固め層１３の底１４から約５０ｃｍの位置に押し込み埋設させ、既製杭２０、２２、２２の埋設を完了させる（図２（ｃ）（ｄ））。ソイルセメントが固化後に、杭穴７内で既製杭２０、２２、２２と根固め層１３及び杭周固定液層１６（ソイルセメント）とが一体となった基礎杭２４を構築する。
【０１４１】
また、ＰＣ５１の画面５２の「杭先端位置表示欄２９」には、既製杭２０、２２の埋設時間が記録されると共に既製杭２０の先端２１の位置が記録され、その施工結果を既製杭２０、２２を埋設しながら、また各基礎杭２４施工毎に確認できるとともに、施工内容の保証データとしても利用できる（図４、図７）。
【０１４２】
【実施例４】
次に、図１６、図１７、図１４に基づき、杭長が長尺となった場合（例えば５０ｍ程度）の施工について説明する（図１４）。
【０１４３】
杭長が長尺（例えば５０ｍ）となった場合、杭打ち機４２のリーダー３５は通常２０ｍ程度であり、長さに限界があるため、掘削ロッド１の上端に他のロッド（掘削ロッド１から掘削ヘッド２を外した構造）の下端を連結して、当該他のロッドの上端をオーガマシン３８に取り付けて掘削を続ける。
【０１４４】
また、逆に、杭穴掘削が完了し、セメントミルクを注入して掘削ロッド１を杭穴７から引上げる際に、杭打ち機４２のリーダー３５の長さに限界があるため、セメントミルクの注入を中断して掘削ロッド１から他のロッド２５を所定長切り離す必要があった。
【０１４５】
即ち、以下の手順で施工を行う。セメントミルクの注入方法、基礎杭２０、２２の埋設方法は、前記実施例２、３と同様である。
【０１４６】
（１）一方の杭芯Ａ側
【０１４７】
前記実施例３のように、杭打ち機４２のオーガマシン３８に取り付けた掘削ロッド１Ａで、所定の深さまで杭穴７Ａの軸部８Ａの上部を掘削し、続いて、掘削ロッド１Ａをオーガマシン３８から取り外し、掘削ロッド１Ａの上端部１ａを杭穴７Ａの上方で仮設支持する。掘削ロッド１Ａの上端１ａに、他の掘削ロッド２５の下端２５ｂを連結すると共に、他の掘削ロッド２５の上端２５ａをオーガマシン３８に連結して、残り（下部）の杭穴軸部８Ａ、拡大根固め部９Ａを掘削する（図１６、図１７（ａ））。
【０１４８】
続いて、掘削ロッド１Ａの掘削ヘッド２Ａの吐出口５Ａからセメントミルクを吐出して、根固め層１３Ａを形成する。続いて、掘削ロッド１Ａ及びロッド１ａを引き上げながら、同様に吐出口５Ａからセメントミルクを吐出して、杭周固定液層１６Ａの下部を形成する。
【０１４９】
この状態で、掘削ロッド１Ａの上端部１ａが地面１８上に現れるので、掘削ロッド１Ａの上端部１ａを杭穴７Ａの上方で仮設支持する。同時に、掘削ロッド１Ａから他の掘削ロッド２５を取り外す（図１６（Ａ−１）、図１７（ｂ））。この状態までの、一方の杭芯Ａ側での杭穴掘削データは、前記実施例３と同様の管理装置で、施工管理されており、そこまでの管理内容が、ＰＣ５１に保存記憶される。杭芯Ａには杭番号が付与されており、この杭番号でＰＣ５１に記憶されるため、容易に読み出し、保存することができる。
【０１５０】
（２）他方の杭芯Ｂ側
【０１５１】
先端に掘削ヘッド２Ａの取付けられている方の掘削ロッド１Ａはそのまま杭穴７Ａ内に保留する。
【０１５２】
同じ杭打ち機４２のオーガマシン３８に、取付けられている他の掘削ロッド２５の先端に他の掘削ヘッド２Ｂを取付けて（図１７（ｃ））、杭打ち機４２は、次の杭芯Ｂ側で、杭穴７Ｂの掘削を開始する（図１６（Ｂ−１））。この際、施工管理は、前記記憶した杭穴７Ａ側の管理とは別に、杭穴８Ｂの施工管理として、実施例３と同じように（杭穴７Ａと同じように）施工管理される。即ち、１台の杭打機４２によって、２つの杭芯（杭埋設位置）Ａ、Ｂで、一方はセメントミルクの充填工程、他方では掘削工程が進行することになる。
【０１５３】
同様に、他の掘削ロッド２５で、杭穴７Ｂの軸部８Ｂの上部を掘削した状態で（図１７（ｄ））、掘削ロッド１Ｂの上端１ａを杭穴７Ｂの上方で仮設支持し、オーガマシン３８から他の掘削ロッド２５を取り外す（図１６（Ｂ−２）、図１７（ｅ））。
【０１５４】
以上の管理内容は、杭芯Ｂ側の管理内容として、アンプボックス５０内あるいは、ＰＣ５１内の記憶装置に一時保存される。また、杭芯Ｂについても杭番号が付されているため、杭穴７Ａと交互に、あるいは同時にＰＣ５１のＰＣの画面５２に表示することができる。
【０１５５】
（３）一方の杭芯Ａ側
【０１５６】
先端に他の掘削ヘッド２Ｂの取付けられている方の他の掘削ロッド２５はそのまま杭穴７Ｂ内に保留する。
【０１５７】
杭打ち機４２を杭芯Ａ付近に移動し、オーガマシン３８に、杭穴７Ａ内に保留された掘削ロッド１Ａの上端部１ａを連結する（図１７（ｆ））。アンプボックス５０内あるいは、ＰＣ５１内の記憶装置に一時保存されていた、杭芯Ａ側の管理情報を読み出し、掘削ロッド１Ａの仮設支持を解除する。
【０１５８】
掘削ロッド１Ａの吐出口５Ａからセメントミルクを吐出して、杭周固定液層１６Ａの上部を形成しながら掘削ロッド１Ａを引き上げる。この際、必要ならば、掘削ロッド１Ａを若干下方に戻してからセメントミルクの吐出を開始することもできる。この場合も掘削ヘッド２Ａの位置は、深度計４５で測定されている。
【０１５９】
掘削ロッド１Ａを杭穴７Ａから引き抜けば（図１７（ｇ））、根固め層１３Ａ、杭周固定液層１６Ａが形成された杭穴７Ａが構築される（図１６（Ａ−２））。
【０１６０】
以下、同様に、杭打ち機４２のオーガマシン３８から掘削ロッド１Ａを取り外し、既製杭２０、２２を埋設して、杭芯Ａに基礎杭２４を構築する。
【０１６１】
（４）他方の杭芯Ｂ側
【０１６２】
杭打ち機４２を杭芯Ｂ付近に移動し、杭穴７Ｂに保留されていた他の掘削ロッド２５の上端部に掘削ロッド１Ｂの下端部を連結すると共に、掘削ロッド１Ｂの上端部を杭打ち機４２のオーガマシン３８に連結する（図１７（ｈ））。アンプボックス５０内あるいは、ＰＣ５１内の記憶装置に一時保存されていた、杭芯Ｂ側の管理情報を読み出し、掘削ロッド１Ｂの仮設支持を解除する。
【０１６３】
尚、ここで、掘削ロッド１Ｂを使用したが、杭芯Ａ側での構築において、取り外した掘削ロッド１Ａ（図１７（ｇ））をそのまま転用することもできる（図示していない）。
【０１６４】
以下同様に、杭穴軸部８Ｂの下部、杭穴拡底部９Ｂを掘削し（図１７（ｉ））、根固め層１３Ｂ、杭周固定液層１６Ｂの下部を形成した状態で、図１６（Ａ−１）と同様に、掘削ロッド１Ｂを杭穴７Ｂの上方で仮設保持する（図示していない）。
【０１６５】
この状態で、杭芯Ｂ側の管理情報を、アンプボックス５０内あるいは、ＰＣ５１内の記憶装置に、再び一時保存する。
【０１６６】
（５） 続いて、杭芯Ｂと同様に、他の杭芯Ｃ側で、施工をする。
【０１６７】
このように、杭芯ごとに杭番号を付して施工管理状況を記憶しているため一方の杭芯Ａの施工管理表示をアンプボックス５０内あるいは、ＰＣ５１内の記憶装置に一時保存した状態で、他方の杭芯Ｂの施工管理状況を表示することができ、また他方の杭芯Ｂの施工管理状況を一時保存して、一方の杭芯Ａの施工管理状況を再度読み出し、セメントミルクの注入が完了、必要とあれば杭埋設完了までの施工管理状況を表示することができる。
【０１６８】
従って、少ない杭打ち機４２でも効率よく活用して、基礎杭を施工することができ、この場合でも、同様の施工管理ができる。
【０１６９】
【発明の効果】
この発明は、注入すべきセメントミルクを複数回に分けて、セメントミルクの吐出口を杭穴底部内で少なくとも２回上下移動させながらセメントミルクを注入するので、固化後形成される根固め層は、外径のバラツキ、圧縮強度のバラツキも少なく安定しており、均質に形成でき、根固め層の品質を高められる効果がある。また、従って、強固な根固め層を形成でき、基礎杭と一体になり杭穴内の基礎杭及び固化物の全体で、杭穴径に相当する高支持力を発揮できる。また、根固め層の固化前の初期沈下に関しても、これを防止できることが期待できる。
【０１７０】
更に、根固め層内を撹拌する装置として、根固め層を掘削した時の掘削ヘッド及びオーガマシン等の掘削装置をそのまま使用して、高支持力を有する均質な層を形成できるように各種の撹拌条件を確立できたので、別途に新たな撹拌装置を準備することもなく、簡便で経済的な撹拌・混合ができた。
【０１７１】
とりわけ、杭穴の底で、全セメントミルク量の 1/3宛をまず吐出する場合には、支持地盤の地質に良くない成分が杭穴内に残存している場合でも、比重の低いこれらの成分をセメントミルクが押し上げ、噴出させることができ、更に安定した高品質の根固め層が得られる。
【０１７２】
この発明の管理方法又は管理装置によれば、杭穴掘削時には、オーガーが負担する負荷電流を積算電流値に変換して、掘削と同時に表示することによって、掘削時の状況及び支持層の設定・確認を行い、引続きセメントミルクを注入の際には、所定深度間隔毎の充填量を注入と同時に表示することによって、注入状況の確認ができ、一貫した基礎杭の施工精度を向上させることができる効果がある。
【０１７３】
注入状況を注入と同時にパーソナルコンピュータ等の情報処理手段で処理して表示することによって、所定深度間隔毎のセメントミルクを、深さに応じた充填量を確実に基準量以上注入できる効果がある。
【０１７４】
杭穴内の所定深度間隔毎に基準量以上のセメントミルクを注入できるため、深さに応じた必要でかつ安定した支持力を得られると共に、構築現場の隣接する基礎杭同士の支持力の不均衡を極力抑えることができる効果がある。
【０１７５】
また、施工管理にあたり、杭穴１つずつ情報処理手段で処理した内容を表示し保存蓄積できるので、各杭穴毎の施工条件をオペレータが混乱することなく、１つの杭打ち機を使用して、１つの杭穴を工程を分割して隣接する杭穴を交互に構築する際にも、一時保存されている施工途中のデータをそのまま継続使用して施工管理できるので、基礎杭を構築する施工効率を高めることができる効果がある。
【図面の簡単な説明】
【図１】（ａ）〜（ｄ）は、この発明の実施例のセメントミルク注入方法を説明する縦断面図である。
【図２】（ａ）〜（ｄ）は、同じくこの発明の実施例のセメントミルク注入方法を説明する縦断面図である。
【図３】セメントミルクの吐出仕様を説明する「セメントミルク吐出量−深さ」のグラフで、（ｂ）（ｃ）は本発明の仕様、（ａ）（ｄ）は比較例の仕様を夫々表す。
【図４】この発明の実施例に使用する掘削中の施工データー表示例である。
【図５】図４の施工データの「Ｎ値表示欄」の拡大図で、縦軸に深度、横軸にＮ値を表示したグラフである。
【図６】図４の施工データの「流量・ヘッド位置表示欄」の拡大図で、縦軸に深度又は流量、横軸に施工所要時間（分）で表示したグラフである。
【図７】図４の施工データの「杭先端位置表示欄」の拡大図で、縦軸に杭先端位置（深度）、横軸に杭を挿入開始してからの所要時間（分）を表示したグラフである。
【図８】図４の施工データの「積算電流値表示欄」の拡大図で、縦軸に深度、横軸に積算電流値を表示したグラフである。
【図９】図４の施工データの「根固め液注入量表示欄」の拡大図で、縦軸に根固め部深度、横軸に根固め液注入量を表示したグラフである。
【図１０】図４の施工データの「杭周固定液注入量表示欄」の拡大図で、縦軸に深度、横軸に杭周固定液注入量を表示したグラフである。
【図１１】この発明の実施に使用する杭打ち機の正面図である。
【図１２】この発明の施工管理装置の実施例で、構成を表す図である。
【図１３】この発明の施工管理方法の実施例のフロー図である。
【図１４】この発明の施工管理方法の他の実施例（実施例４）のフロー図である。
【図１５】この発明の施工方法を説明する縦断面図である。
【図１６】この発明の実施例４の施工方法を説明する縦断面図である。
【図１７】（ａ）〜（ｉ）は、同じく実施例４の施工方法を説明する概略した縦断面図である。
【図１８】この発明の実施に使用する掘削ヘッドで、（ａ）は拡大正面図、（ｂ）は一部を破切した部分拡大側面図である。
【符号の説明】
１ 掘削ロッド
２ 掘削ヘッド
３ 撹拌バー
４ 練付ドラム
５ 吐出口
６ 掘削アーム
７ 杭穴
７ａ 杭穴内壁
８ 杭穴の軸部
９ 杭穴の拡大根固め部
１０ 底（拡大根固め部）
１１ 上縁（拡大根固め部）
１２ 杭穴口
１３ 根固め層
１４ 底（根固め層）
１５ 上端部（根固め層）
２０ 既製杭
２１ 既製杭の先端
２２ 既製杭
２４ 基礎杭
２６ 基本データー表示欄
２７ Ｎ値表示欄
２８ 流量・ヘッド位置表示欄
２９ 杭先端位置表示欄
３０ 積算電流値表示欄
３１ 根固め液注入量表示欄
３２ 杭周固定液注入量表示欄
３８ オーガマシン
４０ 駆動モーター（オーガマシン用）
４１ 巻出し装置（杭打ち機）
４２ 杭打ち機
４４ 負荷電流計
４５ 深度計
４６ プラント
４７ 耐圧ホース
４８ 流量計
５０ アンプ・ボックス
５１ パーソナルコンピュータ（ＰＣ）
５２ ＰＣの画面
５３ 印刷機
５５ オペレータ室
５７ 掘削アームの先端部
５８ 掘削アームの掘削刃[0001]
BACKGROUND OF THE INVENTION
This invention is a method for constructing a pile hole consolidation layer characterized by cement milk injection, which is used when burying a ready-made pile in a pile hole,
Further, the present invention relates to a construction management method for a foundation pile that manages construction of a foundation pile including a construction method for this pile hole consolidation layer, and a construction management device used for the construction management method.
[0002]
[Prior art]
Drilling a pile hole, injecting cement milk into the bottom of the pile hole, forming a consolidation layer, sinking a ready-made pile in the pile hole, and fixing the lower end of the pre-made pile to the consolidation layer It has been broken.
[0003]
Conventionally, the quality of the root hardening layer is managed only by the uniaxial compressive strength after the lapse of a predetermined period of the cement milk itself before pouring into the root hardening part, up to the construction method and management method when forming the root hardening layer. , Did not go around.
[0004]
Further, recently, a method has been performed in which a pre-made pile having a protrusion at least at the lower end is sunk in the pile hole, and the protrusion at the lower end of the pre-made pile is fixed to a rooting layer having an expanded bottom. In this case, since the ready-made pile having the root hardening layer and the protrusion is firmly consolidated, the supporting force is greatly improved.
[0005]
Conventionally, in order to investigate the ground strength and the like, a soil investigation by a standard penetration test is performed according to the size of the construction site prior to the foundation pile construction. In this soil investigation, ground strength is estimated by measuring the number of impacts (N value) required to drive a steel sampler 30cm by boring, and the soil name is determined from the collected samples. A diagram is created.
[0006]
In this case, in confirming the support layer, the current value (integrated current value (Amp · sec), etc.) from the excavator is compared with the soil column diagram of the attached sheet, or the N value of the soil column diagram is integrated with the depth as a reference. A method of displaying current values on the same screen is known (Japanese Patent Laid-Open No. 5-280031 “Pile support layer detection device”).
[0007]
[Problems to be solved by the invention]
According to the construction method in which the structure that mainly contributes to the high bearing capacity, such as the protrusions formed at the lower end of the ready-made piles, is laid in the rooting layer, the performance of the high bearing capacity is approximately twice that of the conventional method. Therefore, in the construction of the root hardening layer that expresses its high bearing capacity, the construction quality of the root hardening layer is important.
[0008]
After excavation of the bottom of the pile hole in the construction of the root solidification layer, this soil cement layer is built to a uniform high solidification strength quality in the process of agitating the excavated soil, injecting and mixing cement milk to form a soil cement. Therefore, there is a demand for a method for constructing a new root hardening layer and quality control of cement milk. While it is necessary for the root-capping layer to be reliably formed in a soil layer of a predetermined strength, in particular, management of the quality and filling amount of the curable material is in question.
[0009]
For example, the root solids of a pile hole having an enlarged bottom part is injected with a root solid liquid, and a pile circumference fixing liquid is injected into the shaft part of the pile hole, and each is mixed with excavated soil to form soil cement, and at least the lower end in the bottom part In the construction method in which the lower end of the pile with protrusions having one or more protrusions in the part is embedded, and the supporting force and the pulling force are greatly improved by the support pressure from the lower end surface of the pile and the protrusions, The ground strength of the root hardening layer, the root solid liquid to be filled, the filling amount per predetermined depth of the pile periphery fixing liquid, and the quality when the soil cement is formed are important management items.
[0010]
In the invention described in Japanese Patent Laid-Open No. 5-280031, the integrated current value from the start of excavation and the N value input in advance are displayed on the same screen with reference to the depth, and the role is played after confirmation of the support layer. Finished. Normally, filling of curable materials such as cement milk is started after the support layer is confirmed, but until now the confirmation of the support layer by measuring the accumulated current value from the beginning of excavation, injection of the curable material, and pile insertion No device has been developed that has a construction management function that correlates the data of each process up to.
[0011]
Furthermore, in addition to the drilling data based on the depth and the integrated current value, there has been no device for confirming the construction status by displaying construction management data such as the injection status of the curable material on the same screen.
[0012]
[Means for Solving the Problems]
However, according to the present invention, the cement milk to be injected is moved into the plurality of times while the injection means is moved up and down in accordance with the data (depth, soil quality) at the time of actual excavation of each pile hole and the discharge port is moved up and down at least twice. The problem was solved because it was divided and injected from the discharge port to form a solidified layer at the bottom of the pile hole.
[0013]
  That is, the present invention forms a rooting layer at the bottom of the pile hole.And, a pile circumference fixed liquid layer is formed in the pile hole shaft,In the method of constructing the foundation layer by injecting cement milk into the bottom of the pile hole when constructing a foundation pile that embeds the ready-made pile in the pile hole and fixes the lower end of the ready-made pile in the root consolidation layer,(1) After excavating the pile hole, the excavation head is held at the bottom of the pile hole, and the total amount of cement milk to be injected from the discharge port is 3 Discharging cement milk addressed to a minute,
(2) Next, while raising the excavating rod to the vicinity of the upper edge of the root consolidation layer to be formed, one third of the total amount of cement milk is discharged, and the strength in the root consolidation layer is not good. The object is pushed up above the rooting layer,
(3) Next, while raising and lowering the excavation rod a plurality of times between the bottoms of the pile holes, the remaining cement milk is discharged, and the excavation rod is pulled up to form a solidified layer.
This is a method for constructing a pile hole consolidation layer characterized by that.
[0016]
  In the above,"For root hardening liquid or pile circumference fixing liquid"Cement milk is injected while displaying the state of cement milk injection on the display unit installed in the construction operation room, construction machine, or construction control room in the construction area, and confirming the construction conditions in the surrounding ground and pile holes., The display on the display unit is the time from the start of construction on the horizontal axis, and the vertical axis indicates "flow rate per hour of the rooting liquid or pile circumference fixing liquid obtained from the flow meter", "discharged material obtained from the flow meter ”Total flow rate” and “the excavation head position obtained from the depth gauge” are graphed and displayed simultaneously.This is a method for constructing a pile hole consolidation layer characterized by that.
[0018]
  Further, the invention of the device includes a rotary drive device for mounting the excavation rod or the ready-made pile, an elevating means for raising and lowering the rotary drive device, and water or"For root hardening liquid or pile circumference fixing liquid"A pile driving machine provided with a liquid supply means for supplying cement milk, comprising various sensors, collectively processing information from the various sensors, displaying the information on the screen, and storing and recording the information In a pile driving device having means,
(1) The various sensors include a load ammeter that measures a load current of the rotary drive device, a depth meter that senses the amount of elevation of the rotary drive device and measures the depth position of the excavation rod or the ready-made pile from the ground, And a flow meter for measuring the amount of liquid supplied from the liquid supply means,
(2) The information processing means displays the data from the flow meter for each depth set from the data from the depth meter, and compares the prescribed flow rate for each preset depth with the actual flow rate. A function for displaying, a function for accumulating and displaying the data from the load ammeter for each predetermined depth, and displaying the corresponding N value data for each predetermined depth set in advance, It has a function that can read, display, store and accumulate information for each pile hole.
(3) The display of data by the information processing means, the horizontal axis is the time from the start of construction, and the vertical axis is "flow rate per hour of water, rooting liquid or pile circumference fixing liquid obtained from a flow meter", " The “total discharge flow rate obtained from the flow meter” and the “excavation head position obtained from the depth meter” are graphed and displayed simultaneously.
This is a construction management device for foundation piles.
[0019]
  Also,In the apparatus, a discharge port is formed at a lower end portion of a drilling rod having a drilling head,
When pouring cement milk into the pile hole root hardening layer,
(1) After excavating the pile hole, hold the excavation head at the bottom of the pile hole, and discharge the cement milk addressed to one third of the total amount of cement milk to be injected from the discharge port;
(2) Next, while raising the excavating rod to the vicinity of the upper edge of the root consolidation layer to be formed, one third of the total amount of cement milk is discharged, and the strength in the root consolidation layer is not good. The object is pushed up above the rooting layer,
(3) Next, while raising and lowering the excavation rod a plurality of times between the bottoms of the pile holes, the remaining cement milk is discharged, and the excavation rod is pulled up to form a solidified layer.
It is a construction management device for foundation piles.
[0020]
  Further, the invention of the management method includes a rotary drive device to which the excavation rod or the ready-made pile is attached, an elevating means for moving the rotary drive device up and down, and water or"For root hardening liquid or pile circumference fixing liquid"Excavation process for excavating a pile hole using a pile driving machine provided with a liquid supply means for supplying cement milk, an injection process for injecting cement milk into the pile hole, and a ready-made pile in the pile hole into which cement milk has been injected A method of managing a construction method comprising a pile insertion process of burying
Depth for measuring the depth position from the ground of the excavation rod tip or ready-made pile tip by sensing the data from the load ammeter that measures the load current of the rotary drive and the amount of lift of the rotary drive Data from the total,
Calculate and process data from a flow meter that measures the amount of liquid supplied from the liquid supply means, and store these data so that they can be read for each pile hole,
For each pile hole,
(1) In the excavation process, the data from the load ammeter is accumulated and displayed for each predetermined depth, and displayed in comparison with the corresponding N value data for each predetermined depth, Check the support layer.
(2) In the injection process, The horizontal axis is the time from the start of construction, and the vertical axis is "flow per hour of water, solidification liquid or pile circumference fixing liquid obtained from the flow meter", "total flow rate of discharge obtained from the flow meter" and While graphing the "position of the excavation head obtained from the depth gauge" simultaneously,
The prescribed flow rate at each depth set in advance and the actual flow rate are compared and displayed, and the amount of cement milk at each depth is managed.
(3) In the pile insertion process, the pile tip position is managed from the data from the depth gauge, and it is managed that the ready-made pile is fixed on the support layer.
A construction management method for foundation piles characterized by that.
[0021]
  In the above,Forming a discharge port at the lower end of a drilling rod having a drilling head;When injecting cement milk into the pile hole consolidation layer,
(1) After excavating the pile hole, hold the excavation head at the bottom of the pile hole, and discharge the cement milk addressed to one third of the total amount of cement milk to be injected from the discharge port;
(2) Next, while raising the excavating rod to the vicinity of the upper edge of the root consolidation layer to be formed, one third of the total amount of cement milk is discharged, and the strength in the root consolidation layer is not good. The object is pushed up above the rooting layer,
(3) Next, while raising and lowering the excavation rod a plurality of times between the bottoms of the pile holes, the remaining cement milk is discharged, and the excavation rod is pulled up to form a solidified layer.
Characterized claims5The construction management method of the foundation pile described.
[0022]
In the above, the injection means is a device capable of injecting cement milk, and generally uses a hollow excavation rod having an excavation head at the lower end, but after raising the excavation rod, such as an injection pipe provided with stirring means An injection means can be separately prepared and used.
[0023]
In addition, in the above, in addition to the case where the root consolidation layer has the same hole diameter as that of the shaft portion, and in the case of the expanded root consolidation layer that has been expanded and drilled, the root consolidation layer generally exhibits a high bearing capacity. Since a high quality of the layer is required, a more remarkable effect can be expected.
[0024]
In the above, the surrounding ground state is based on other pile hole data, standard penetration test data, test digging data, etc., and these or any one of them and the data of this pile hole are displayed on the display device. Therefore, highly accurate construction can be performed while confirming in comparison with the injection of cement milk.
[0025]
Moreover, the cement milk in the above is a general term for hydraulic materials, and any material can be used as long as it can form a solidified layer including various cements.
[0026]
The construction management means that the construction conditions / set values are compared with the actual data, and if there is a difference, adjustment is made to match the conditions / set values.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
A drilling rod having a drilling head (with a drilling blade) at the lower end is formed in a hollow shape, constitutes cement milk injection means, and a discharge port is formed at the lower end. After excavation is completed, cement milk addressed to one third of the total amount of cement milk is discharged from the discharge port while stirring with the excavation head while holding the excavation head at the bottom of the pile hole. Subsequently, while agitating with the excavation head, one third of the total amount of cement milk is discharged while the excavation rod is raised to the vicinity of the upper edge of the pile hole root consolidation part. Next, while raising and lowering the excavation head several times within the rooting part (between the bottom of the pile hole and the upper edge of the rooting part), one third of the remaining cement milk is discharged, and stirring and mixing are performed. The drilling rod is pulled up to form a rooting layer.
[0028]
It is a structure which is formed in the lower end part of a ready-made pile and expresses high bearing power in the formed root hardening layer. For example, by fixing the protruding portion formed on the lower end portion of the ready-made pile, the cement milk and the ready-made pile are integrated after the cement milk is solidified, and a foundation pile that exhibits high supporting force can be constructed.
[0029]
Here, agitation refers to a step of rotating the excavation head, and mixing refers to a step of moving the excavation head up and down (or repeating rotation and elevation).
[0030]
In this case, in the construction of a high-quality root consolidation part that expresses a high bearing capacity, new construction different from conventional ones, including the quality of the injected cement milk, excavation of pile holes, embedding of foundation piles, etc., must be ensured. It is necessary to have a mechanism to ensure that the system is implemented.
[0031]
The new construction method including the present invention has a more precise construction procedure and method than the conventional construction method, and it is difficult to guarantee the quality with a mechanism that only records part of the data at the time of the conventional construction. Construction of the management system guarantees the construction content and quality of the high bearing capacity consolidation part.
[0032]
In addition, the conventional foundation pile construction method with a root consolidation part is relatively simple in both procedure and method, and displays and records the excavation load current of the excavator as a document to prove that the pile was buried in the supporting ground. It was only about. That is, no further maintenance / management system was required in terms of the required quality and reliability of foundation piles.
[0033]
The display shows the excavation current value along with the depth of the excavated stratum, and the excavation load current is the extent to which the difference from the pile burial depth assumed from the previous boring data was used as an indication. The actual values for each set condition other than those for each foundation pile are recorded and compared in real time, and the construction contents of the foundation pile are confirmed at the construction site, recorded and used for quality maintenance and management purposes. There was nothing, and at most, the recorded values were sorted and compared after construction. In actual construction, there was almost no constant feedback to the construction work while confirming and checking each pile foundation construction or each pile construction.
[0034]
[Test example]
A comparative experiment was carried out between the root hardening layer obtained by the method of the present invention and the root hardening layer obtained by the conventional method. It was confirmed that a solidified layer consisting of a homogeneous high-quality soil cement layer was obtained by improving the timing of cement milk injection and stirring and mixing.
[0035]
1. Test conditions and specifications
[0036]
(1) Pile hole, excavation method, etc.
Support layer geology: N value 30-35, sandy soil
Pile hole: Shaft diameter 800mm
Shaft length 950mm
Expanded root firming part diameter 1200mm
Expanded root hardening part length 2500mm
Outline of creation method: With a special excavation head with an injection port, water is poured into the pile hole shaft, and 9.5m is excavated from the ground. Excavate and stir well to form an enlarged root consolidation part (root consolidation layer to be constructed). Next, cement milk having the following specifications is injected and mixed with the excavated soil, and the solidified portion is used as a soil cement layer (FIG. 3).
[0037]
(2) Cement milk combination
Cement amount: 1090 kg
Water: 654 liters
Kneading amount: 1m³
[0038]
(3) Specification of cement milk agitation
As a specification for stirring and mixing cement milk and excavated soil, the excavating rod 1 with the excavating head 2 is used as it is as a stirring apparatus. That is, the excavation head 2 having a feature capable of finely crushing excavated soil is provided with excavating arms 6 and 6 that swing on both sides of the head body 6 a connected to the shaft portion of the excavating rod 1. The front end portion 57 of this is formed to open to the outside, and excavation blades 58 and 58 are attached (FIGS. 18A and 18B).
[0039]
Length D of swinging excavating arm 6 at an excavation diameter of 80 to 110 cm at the root of the pile hole₀(= About 50 to 80 cm), the length of the tip 57 of the large area is L₁As L₁D₀About 30-40% of the length. When the area outside the distal end portion 57 having a large area including the excavating blades 58, 58 is S (the net line portion in FIG. 18A),
S = “(L₁)²About 70-80% "
As a result, good and homogeneous stirring and mixing can be obtained.
[0040]
Further, the agitating power for rotating the excavation rod 1 (excavation head 2) is also used as it is for the auger machine during excavation. Normally, during excavation, the auger machine power supply voltage is kept constant and the output is increased, and the excavation current is raised and lowered to control the rotational speed to be constant. In general, auger machines with different outputs are used depending on the geology and ground strength.
[0041]
And at the time of agitation, it is controlled so as to increase the number of revolutions to 1.5 to 2.0 times the average number of revolutions of the excavating rod 1 at the time of excavation, and a specification for stirring and mixing while injecting cement milk as will be described later. Adopted.
[0042]
(4) Specification of cement milk injection
After excavating the bottom of the pile hole to form a pile hole having a root shape with a predetermined shape, cement milk is injected into the root shape at a discharge rate of about 200 liters / minute. Comparison was made according to the following four specifications (FIGS. 3A to 3D).
[0043]
(a) Specification 1 (Case 1): Conventional example (Fig. 3 (a))
First, place the cement milk inlet at the center of the bottom of the root-clamping part. Forming a root hardening layer.
Total injection amount to root consolidation: 2.4m³
[0044]
(b) Specification 2 (Case 2): The present invention (FIG. 3 (b))
Dispense the total discharge amount in 1/3 of 3 times.
1st time: Dispense 1/3 amount with stirring at the bottom of the planned solidification layer.
2nd: Raise 1/3 volume and discharge while stirring.
Third time: Discharge is completed while reciprocating up and down two times in the rooting portion while stirring 1/3 amount.
[0045]
(c) Specification 3 (Case 3): the present invention (FIG. 3 (c))
First, the cement milk injection port is installed at substantially the center of the bottom of the root consolidation layer to be constructed, and the inside of the root consolidation is reciprocated up and down twice while stirring and discharging, and is completed at the top.
[0046]
(d) Specification 4 (Case 4): Conventional example (Fig. 3 (d))
First, the cement milk injection port is installed at the approximate center of the bottom of the rooting portion, and the entire amount of cement milk is discharged without moving the injection port to form a soil cement layer. This method is mainly used when silt or the like is mixed and the formation is not good.
[0047]
(5) Test evaluation method
(a) Electrical resistivity measurement test
Immediately after completion of the cement milk discharge and formation of the rooting layer, a specific resistance rod was inserted into the rooting layer, and the electrical resistivity was measured from the upper layer to the lower layer of the rooting layer.
(b) Uniaxial compressive strength test of sampled core
After the cement milk of the expanded root-solidified layer was solidified, core-boring of the expanded root-hardened layer was performed and divided into approximately 4 equal parts in the vertical direction, and each uniaxial compressive strength test was performed.
[0048]
2. Test results
The summary of the test results is shown in Table 1 below.
[0049]
[Table 1]

[0050]
In addition, since the absolute value of each measured value of the test is essentially different depending on the measurement timing, the geological strength at each measurement point, etc., it is appropriate to compare the construction methods with variations in measured values. The measured value of uniaxial compressive strength is 22 N / mm²Before and after, the measured value of electrical resistivity was around 5 Ωm.
[0051]
3. Summary of test results
(a) The compressive strength variation of the new specifications (Case 2 and Case 3) is stable at 10% or less, which is improved to 1/2 or less compared to the conventional specifications (Case 1 and Case 4). Furthermore, a micro comparison of the electrical specifications between the new specifications shows that the specifications 2 are more homogeneous.
Therefore, it can be seen that the method of discharging cement milk while stirring and raising and lowering it at least twice is effective.
(b) If the excavated soil contains silt or the like that is not good in strength, it is desirable to discharge cement milk at the bottom (without stirring) and push it upward (shaft) above the expanded root-solidified layer. Therefore, it can be said that the specification 2 is desirable also from this viewpoint.
(c) Although not compared this time, the results of this test show that the construction method in which excavation of the solidified layer and injection of cement milk cannot be performed at the bottom makes it impossible to discharge cement milk. It is judged that the cement milk in the layer varies and the performance of the root hardening layer is inferior.
[0052]
(d) As a stirring method, when mixing with the above specifications, the drilling head 2 is used as it is as a stirring device, so there is no time loss due to exchanging the drilling rod 1, and it is simple and easy to mix. Since the tip 57 of the excavating arm 6 that contributes most (located on the outer peripheral side during agitation) is formed with a large area, the agitation efficiency at the periphery of the pile hole is good, and there is further excavated soil that is not sufficiently crushed However, since it can be further finely pulverized, uniform mixing is possible. Moreover, since it rotates at a high speed 1.5 to 2.0 times during excavation, the stirring efficiency is further improved.
[0053]
In addition, since the auger machine used at the time of excavation was used as the agitation power source, it functions as an agitation power source suitable for the soil quality and is reliable and stable even when rotating up to twice the number of revolutions at the time of excavation. Stirring and mixing became possible.
[0054]
Therefore, it was possible to establish an economically excellent construction method capable of carrying out homogeneous stirring and mixing by using the excavating apparatus such as the excavating head 2, the excavating rod 1 and the auger machine when excavating the pile hole.
[0055]
[Example 1]
An embodiment of the present invention will be described with reference to FIGS.
[0056]
(1) Excavation of pile hole shaft 8
[0057]
At the construction site, the excavator is installed, and the pile hole 7 is excavated with the excavation rod 1 having the excavation head 2 at the tip at a predetermined pile embedding position (FIGS. 1A and 1B). The excavation rod 1 is provided with kneading drums 4 and 4 for leveling the stirring bars 3 and 3 and the inner walls of the pile holes in the middle part. Further, when excavating the pile hole 7, the excavation status (various information) is displayed on the display device (various display devices) in the operator room of the excavator (FIG. 4).
[0058]
The excavation diameter of the pile hole 7 is the pile hole shaft portion 8 in which the diameter (750φ) +30 mm of the ready-made pile to be buried is secured. In the middle of the excavation, an appropriate amount of water is poured from the discharge port 5 provided in the excavation head 2, and the excavated soil is sufficiently agitated by the agitation bars 3 and 3 to be mud, and the kneading drums 4 and 4 are applied to the inner wall 7 a. Kneading and excavating to a depth of 46.5m.
[0059]
The measurement result of the standard penetration test obtained on the construction ground is displayed in the “N value display column 27” in advance (FIG. 5), and based on this measurement result, the excavation depth and the N value at that depth are displayed. On the other hand, the accumulated value (recorded value) of the excavation load current is displayed in parallel in the “integrated current value display field 30” (FIG. 8), and excavation is performed while comparing and confirming both. If the recorded value in the support ground at the planned depth does not match, the excavation depth is adjusted. At the same time, the depth at that time and the amount of water injected during excavation (A1) are also displayed and recorded together in the “flow rate / head position display column 28” (FIG. 6), so confirmation and adjustment are performed.
[0060]
The recorded value as the accumulated value of the digging load current in the “accumulated current value display field 30” in the display device is the accumulated value of the digging load current as the recorded value in order to match the N value (indentation size 30 cm) of the penetration test. The excavation size is appropriately variably set within a range of 30 to 50 cm for each predetermined depth. Here, as a result of accumulating and displaying a load current having a width of 50 cm at every depth of 50 cm, it was confirmed that a value of a tendency that substantially matched the change in the N value of the penetration test was obtained (FIG. 8). Therefore, the recorded value is a load current accumulation value with a width of 50 cm and is displayed in A · sec (ampere · second).
[0061]
In addition, by displaying the load current value every 50 cm, the accuracy can be improved by a factor of about 2 times compared to the measurement at a 1 m interval in the normal standard penetration test.
[0062]
That is, the measurement of the N value in the standard penetration test indicates the number of hits in which the sampler having a weight of 63.5 kg is driven in the depth direction by 30 cm in the soil layer range, and this method is used for every 50 cm soil layer range used before and after the hitting. In addition, the strength of the ground can be displayed as a numerical value proportional to the amount of work.
[0063]
Therefore, using the fact that the power supply of a normal excavator is controlled at a constant voltage, and further assuming that the load current during excavation of this excavator is proportional to the ground strength, the soil used in the standard penetration test is used. By accumulating this load current in the same range (30-50cm) as the layer width and displaying it simply in units of work proportional to the time product (ampere-second) of the load current, that is, the ground strength, By comparing the ground strength at the excavation point and the N value for each excavation hole, it is possible to perform construction with a reliable construction position of the foundation layer. Here, the accumulated soil layer width is close to the measured soil layer width dimension in the standard penetration test, if there is much variation in soil quality, or adjusting the range of the soil layer width in the range of 30-50cm if necessary. Good consistency.
[0064]
That is, since the time product of the load current of the excavator is displayed in this way, the excavation current at the time of excavating the pile hole is almost the same range as the soil layer width used in the N value measurement of the standard penetration test ( 30 to 50 cm), and when the accumulation is completed, it is recorded and displayed at each depth. Therefore, in the case of the standard penetration test, the “number of depths (every 50 cm)” indication of the number of hits is displayed. It can be adapted to “every depth”.
[0065]
Therefore, with respect to the ground strength at the construction site, it is possible to supplement the few standard penetration test data and grasp the high-precision ground condition of the entire construction site, and to set an appropriate support layer for each pile foundation, making it a safer and more reliable foundation. Can be provided easily.
[0066]
Thereafter, the excavation head 2 is repeatedly moved up and down while stirring the excavated soil, and the pile hole shaft portion 8 is constructed (FIG. 1B). The supporting ground was sandy soil, and the N value was 30 or more. Based on this excavation result (excavation depth, etc.), it is also possible to change the set value of the “basic data display column 26” for each pile hole.
[0067]
(2) Excavation of the enlarged solidified portion 9 of the pile hole 7
[0068]
Next, the excavation diameter is expanded, and water is poured from the discharge port 5 to construct an enlarged root consolidation portion 9 having an enlargement diameter of 1100 mm and a depth of 2.5 m, and the excavated soil is stirred up and down twice (see FIG. 1 (c)).
[0069]
In the "flow rate / head position display field 28" in the display device, the display record is to confirm and adjust the excavation depth and the water injection amount (FIG. 6).
[0070]
(3) Cement milk injection at the enlarged root consolidation part 9 (formation of root consolidation layer)
[0071]
Using the method of the present invention, cement milk is injected to form a homogeneous root hardening layer (soil cement layer) 13.
[0072]
Cement milk for root consolidation is 2590 kg of cement (according to JASS4 Section 2.2.1), 1554 kg of water, and kneaded to 2.38 m.³And
[0073]
First, the discharge port 5 of the excavation head 2 is held in the vicinity of the bottom 10 at the center of the enlarged root consolidation portion 9, and the total amount of root consolidation liquid (cement milk of the above-mentioned mixing ratio) (2.38 m) is used.³1/3 is discharged at about 200 liters per minute while being agitated by the excavation head 2 (first discharge, FIG. 1 (c), FIG. 3 (b)).
[0074]
Next, the excavating head 2 is pulled up to the top while stirring the root-setting liquid in the same manner (FIG. 1 (d)). In the meantime, 1/3 of the total use amount of the root hardening liquid is discharged (second discharge, FIG. 3 (b)).
[0075]
Next, while discharging the root-setting liquid in the same manner, the excavation head 2 is reciprocated twice up and down to reach the bottom 10 and to 1/3 of the remaining amount of the root-setting liquid until the end, that is, above the standard While injecting the cement milk, the soil is stirred and mixed with the excavated soil to form a soil cement layer (the third discharge, FIG. 3B).
[0076]
In the “flow rate / head position display field 28” of the display device, the position (depth m) of the excavation head 2 at that time, the cement milk flow rate (m³/ h) is displayed and recorded (Fig. 6), and the position of the excavation head 2 and the amount of solidification liquid injection (m³) Only enlarged display can be easily compared and adjusted for the amount of root hardening liquid injection, and the management accuracy can be improved. The liquid injection amount can be confirmed (FIG. 9). For example, when the injection amount is insufficient, correction is performed by reinjection. In addition, each construction condition and actual record value are recorded by comparison, and can be used as construction proof material even after construction.
[0077]
(4) Cement milk injection at pile hole shaft 8 (formation of soil cement layer)
[0078]
Cement milk for pile hole shafts has the same mixing ratio as the root hardening liquid, but is also called a pile circumference fixing liquid (peripheral fixing liquid). Cement milk is discharged at a rate of 100 liters per minute. The total injection volume is 2.22m.³This is the above ("basic data display field 26" in FIG. 4).
[0079]
First, discharge starts from the upper end 15 of the enlarged root-setting part 9, and the excavation head (injection port) moves up and down once to a depth of 30 m while stirring, and then excavates while discharging and stirring in the same manner up to a depth of 12 m. The head 2 is reciprocated up and down once, then the excavation head 2 is reciprocated up and down one time while discharging and stirring in the same manner up to a depth of 2 m, and finally the excavation head 2 is reciprocated up and down while discharging and stirring similarly to the pile hole 12. The injection is completed (FIGS. 2A and 2B). In this way, a pile periphery fixing liquid layer (soil cement layer) 16 is formed in the pile hole shaft portion 8.
[0080]
In the “pile circumference fixed liquid injection amount display field 32” of the display device, the position (depth m) of the excavation head 2 and the cement milk flow rate (m³/ H) is displayed and recorded, and the position of the excavation head 2 and the injection amount (m³If the enlarged display of only / h) is selected, it can be easily confirmed whether cement milk has been injected according to the procedure (FIGS. 6 and 10).
[0081]
Therefore, correction such as replenishment of cement milk injection can be performed during the construction of each foundation pile, and it can be proved that the construction has been performed according to a predetermined procedure.
[0082]
In the “flow rate / head position display column” (FIG. 6), the graph A shows the discharge amount per unit (unit m).³/ H) is displayed with the vertical axis as the required time for construction, the water is discharged from the discharge port 5 from 0 to 37 minutes (A1), and the rooting liquid is discharged from 37 to 46 minutes ( A2) After 46 minutes, the peripheral fixative is being discharged (A3). Further, in graph B, the total flow rate of water, root hardening liquid, and peripheral fixing liquid discharged from the discharge port 5 is sequentially displayed. In the graph C, the vertical axis is set to the depth (m) from the ground, the horizontal axis is the time required for construction, and the position of the excavation head 2 is displayed.
[0083]
(5) Burial of ready-made piles 20 and 22
[0084]
The excavation head 2 is removed from the excavation rod 1 and, first, “BF6075-5m” ready-made pile 20 (shaft diameter: φ600, nodal diameter: φ750, nodal pile) (“BF” is a trademark of the nodal pile of Mitani Sexan Corporation. The same applies hereinafter) to the rod 1 and is placed in a pile hole 7 filled with soil cement while rotating. Next, the “SCφ600-14m” ready-made pile 22 is connected and laid, and thereafter, the “SCφ600-15m” ready-made pile 22 and the “SCφ600-15m” ready-made pile 22 are sequentially connected in the same manner, and the “BF6075” at the tip of the connected pile is connected. “-5 m” The tip 21 of the ready-made pile 20 is pushed and embedded at a position of about 50 cm from the bottom 14 of the expanded root-sealing layer 13 to complete the embedding of the ready-made piles 20 and 22 (FIGS. 2C and 2D). After the soil cement is solidified, a foundation pile 24 in which the ready-made piles 20 and 22, the root hardening layer 13, and the pile circumferential fixed liquid layer 16 (soil cement) are integrated in the pile hole 7 is constructed.
[0085]
Further, in the “pile tip position display field 29” of the display device, the burying time of the ready-made piles 20 and 22 is recorded, and the position of the tip 21 of the ready-made pile 20 is recorded. While being buried, it can be confirmed for each foundation pile 24 construction, and can also be used as guarantee data for construction contents (FIGS. 4 and 7).
[0086]
(6) Evaluation of completed foundation pile 24
[0087]
(a) Maximum load
The load at the time of subsidence of 0.1D (D is the diameter of the nose pile shaft) in the loading test of the upper part of the root consolidation part (the ready-made pile 20 and the root consolidation layer 13) is 7000 kN or more, and has a high bearing capacity. It was confirmed that the quality was established. That is, more than twice the normal foundation pile was obtained.
[0088]
(b) Soundness of root consolidation
As a result of digging up the root consolidation part (the ready-made pile 20 and the root consolidation layer 13) and investigating its external appearance and shape dimensions, it was confirmed that there was no crack or large defect and that a root consolidation part with a diameter larger than a predetermined excavation diameter was created. It was done.
[0089]
(7) Effect of display recording
[0090]
Various data can be displayed and output on the display device in the format of FIG. 4 (FIGS. 5 to 10). In the “basic data display field 26” at the upper end of the display field of the display device, the “specification of ready-made piles to be used”, “excavation length”, “pile top position”, “combination of cement milk”, “amount of rooting liquid injection” And “pile circumference fixed liquid injection amount” are displayed (FIG. 4). As for the “solidification liquid injection amount and pile circumference fixing liquid injection amount”, the standard amount (design value) is displayed before construction, and the actual usage amount is sequentially displayed during construction.
[0091]
(a) Since the depth of the drilling hole, the accumulated value of the drilling load current (recorded value of N value substitute characteristics), and the actual measurement value of the flow meter are displayed in comparison, the construction status of the rooting part etc. can be confirmed and managed in real time ( FIG.5, FIG.6, FIG.8-10.
(b) Since the ground strength can be confirmed by the approximate substitution characteristic (load current accumulation value) of N value, an appropriate support layer can be set (FIGS. 5 and 8).
(c) Cement milk injection and agitation can be confirmed and managed in parallel by elapsed time and depth. Moreover, based on the actual excavation data (support layer position, etc.) of the pile hole, the setting conditions such as the injection position and amount of cement milk can be corrected.
(d) Comprehensive quality certification material that confirms whether or not construction has been carried out, and can be used as an actual record of a more detailed construction report than before (Figure 4).
[0092]
[Example 2]
Next, another embodiment of the present invention will be described.
[0093]
(1) Basic configuration of the pile driver 42
[0094]
In the pile driving machine 42 used for carrying out the present invention, a leader 35 is erected on one side of a base 34 that can be self-propelled, and a wire 37 is moved up and down via a top sheave 36 provided at the upper end of the leader 35. The auger machine 38 is connected to the tip of the wire 37. The base end of the wire 37 is attached to the shaft of an unwinding motor (not shown) via an unwinding device 41 attached on the base 34.
[0095]
A box 39 containing a drive motor 40 is attached to the base end of the auger machine 38, and a drilling rod 1 that is rotationally driven by the drive motor 40 is suspended below the box 39. The excavation rod 1 is the same as in the first embodiment, and the excavation head 2 is attached to the lower end, and the excavation rod 1 is kneaded with a plurality of stirring rods 3 and 3 along the axial direction at a predetermined interval. Drums 4 and 4 are disposed.
[0096]
Reference numeral 43 in the figure denotes a generator for supplying electricity to the drive motor 40 of the auger machine 38, the wire unwinding motor, and the like (FIG. 11). The electricity supplied from the generator 43 is sent to the switchboard 43a provided in the pile driver 42, and is then distributed to the auger machine 38 and the like.
[0097]
(2) Configuration of construction management device
[0098]
Next, the control system of this apparatus will be described.
[0099]
(a) Sensors
A load ammeter 44 for measuring the load current of the drive motor 40 of the auger machine 38 is connected to the switchboard 43 a or the generator 43 provided in the pile driving machine 42. Data from the load ammeter 44 is input to the amplifier box 50 in the operator room (FIG. 12).
[0100]
Further, a depth meter 45 comprising a rotary encoder is installed at the lower end of the leader 35 of the pile driver 42 (FIG. 11), and a depth measuring wire 37a is attached to the auger machine 38 along the leader 35 via the depth meter 45. It has been. Thereby, the amount of descent of the auger machine 38, that is, the excavation depth is detected. Data from the depth meter 45 is input to the amplifier box 50 in the operator room (FIG. 12). The depth meter 45 is not limited to the rotary encoder, and may be another measuring tool. The depth meter 45 may measure the depth from the amount of the wire 37 attached to the auger machine 38.
[0101]
Here, the depth meter 45 is the lower end portion of the leader 35, but it may be provided at any position of the leader 35 or in the auger machine 38.
[0102]
In addition, a plant 46 for generating and sending curable materials such as water and cement milk is installed in the construction site (or close to the construction site), and the plant 46 and the pile driving machine 42 are connected by a pressure hose 47. ing. The pressure hose 47 is connected to the auger machine 38 so as to be discharged from the discharge port 5 of the excavation head 2 through the excavation rod 1. A flow meter 48 for detecting the discharge amount is installed at an intermediate portion of the pressure-resistant hose 47, for example, on the pile driving machine 42 side of the base 34 (FIG. 11). The data of the flow meter 48 is input to the amplifier box 50 in the operator room (FIG. 12).
[0103]
Corresponding to the start of lowering of the auger machine 38 (operation of the depth gauge 45), the required construction time (min.) From the start of excavation is measured.
[0104]
(b) Management device
Data collected from the sensors 44, 45, and 48 in the amplifier box 50 are controlled, calculated, and processed by a personal computer (hereinafter, PC) 51 and displayed on a screen (data display device) 52. The paper output to the printing machine 53 is also possible by the operation from. Since the data obtained from the load ammeter 44, the depth meter 45, and the flow meter 48 are generally analog signals, they are converted into digital signals by the A / D converter in the amplifier box 50 and sent to the PC 51.
[0105]
Here, the operator room 55 is arranged in a plant, a facility in a site site such as a resident office of a site construction manager or the like, a control room of a pile driving machine, or an independent facility outside the site. The The operator's room is preferably a facility with a roof (for example, a temporary building, a temporary tent, etc.) in consideration of rainy weather or the like.
[0106]
Further, the data collected by the amplifier box 50 and processed by the PC 51 is displayed on the screen 52 as shown below, divided into display columns 27 to 32 (FIG. 4). Moreover, each display column 27-32 can be switched independently, and can be expanded and displayed (FIGS. 5-10). Also, a plurality of columns can be combined and displayed (not shown).
[0107]
That is, the data from the depth meter 45 is processed, and a graph corresponding to the pile tip position (m) from the ground 18 on the vertical axis and the pile insertion time (min.) On the horizontal axis is displayed on the screen 52. It is displayed in the “pile tip position display field 29” (FIGS. 7 and 4).
[0108]
Further, the data from the depth meter 45 and the load ammeter 44 are accumulated by accumulating the load current of the drive motor 40 required for a certain excavation range (for example, every depth of 30 cm) in the time required for the excavation range. It is processed as an integrated current recording value (Amp × sec). The data from the depth meter 45 is separately processed and graphed correspondingly with the depth (m) from the ground 18 as the vertical axis and the accumulated current recorded value as the horizontal axis. Column 30 "(FIGS. 8 and 4).
[0109]
Further, based on actual excavation data (support layer position, etc.) of the pile holes, the set value of the “basic data display field 26” is corrected and displayed for each pile hole as necessary.
[0110]
Also, the amount of root hardening liquid injected from the flow meter 48 (m³) On the horizontal axis, and the data from the depth meter 45 is set on the vertical axis as the depth (m) from the ground 18, and is graphed correspondingly. Is displayed. At this time, the “specified amount of the root hardening liquid at the time of design” for each depth is displayed at the same time, and the design amount reviewed by the excavation data can be compared with the actual injection amount (FIGS. 9 and 4). In this case, when the actual injection amount reaches the design amount for each depth, the guidance display can be blinked on the screen 52 or a warning sound can be generated.
[0111]
Similarly, the amount of pile circumference fixing liquid injected from the flow meter 48 (m³) On the horizontal axis, the data from the depth meter 45 is set on the vertical axis as the depth (m) from the ground 18, and is graphed correspondingly. 32 ”. At this time, the “specified amount of pile periphery fixing liquid at the time of design” for each depth is displayed at the same time, and the design amount and the actual injection amount can be compared (FIGS. 10 and 4). In this case, when the actual injection amount reaches the design amount for each depth, the guidance display can be blinked on the screen 52 or an audible sound can be emitted.
[0112]
In addition, boring data (N value, soil name, etc.) at the time of the standard penetration test is input to the PC 51 in advance. The data of the depth (m) received from the depth meter 45 from the depth meter 45 is plotted on the vertical axis, and the “N value” for each depth (m) is plotted on the horizontal axis. Is displayed in the value display field 27 "(FIGS. 5 and 4). In this case, other boring data (soil name, etc.) other than the N value can be simultaneously displayed for each depth (m) corresponding to the N value (not shown).
[0113]
Further, the flow rate per hour (m for excavation water, root hardening liquid or pile circumference fixing liquid) from the flowmeter 48 on the vertical axis and on the vertical axis on the required time (min.) From the start of construction (m.)³/ H) is displayed. Similarly, on the vertical axis, the total flow rate of the discharged material (cumulative flow rate. M³) Are displayed at the same time. Similarly, on the vertical axis, “head position (m)” from the ground 18 obtained from the depth meter 45 is simultaneously displayed. Three graphs having the required time (min.) As a common horizontal axis are simultaneously displayed in the “flow rate / head position display column 28” of the screen 52 (FIGS. 6 and 4).
[0114]
Information processing function (calculation, control) as described above, screen 52, “PC 51” and “printer 53” with built-in or external storage means, depth meter 45, flow meter 48, and load ammeter 44 The “amp box 50” to which the sensors are connected and the “power supply device (for example, generator 54, capacitor etc.)” that supplies the rated power to the PC 51, the amplifier box 50, and the printing press 53 provide the construction management device of the present invention. Constitute.
[0115]
In addition, a wireless transmission antenna is attached to an “amplifier box 50” to which sensors including a depth meter 45, a flow meter 48, and a current detector 44 are connected, and wireless reception is performed by a PC 51 installed in a remote place (for example, in the office of a construction site). It is also possible to wirelessly transmit and receive various data collected in the amplifier box 50 by attaching an antenna (not shown). In this way, storage of construction management data and installation of control devices outside the construction site isolates the construction site from dust, mud scattering, rain, etc., and damage caused by construction machine vibrations. Information can be used stably.
[0116]
In addition, by using the Internet or the like, it is possible to obtain construction information from outside the construction site at any time and use it for construction progress management and the like.
[0117]
[Example 3]
Next, a construction management method using this construction management apparatus will be described (FIG. 13).
[0118]
(1) “Pile used (here, upper pile, middle pile, lower pile, type outer diameter, length, etc.)” and “depth of drilling hole (GL (ground 18 ) Depth from ”“ Pile crest (position from GL (ground 18)) ”“ Contained cement milk (per batch) 750 kg of cement, 450 kg of water, scoured 0.69 m³) "" Standard value of the root hardening liquid injection amount (here 2.38 m³) "" Standard value of the amount of fixed fluid injected around the pile (here 2.22m)³) ". These data are displayed in the “basic data display field 26” at the top of the screen 52 (FIG. 4). Note that the “injection amount of root hardening liquid” and “injection amount of fixed fluid around the pile” are sequentially displayed in parallel with the standard values reviewed by the excavation data.
[0119]
The standard value is, for example,
Pile shaft diameter 600mm
Protrusion diameter 750mm
Pile hole shaft diameter 780mm
Pile hole widening part diameter 1100mm
In the case of
The filling amount of root hardening liquid is 0.061m every 10cm.³,
Filling amount of pile fixing liquid is 0.0478m per 1m³,
It will be about.
[0120]
(2) Also, previously obtained boring data (N value, soil name, etc.) is input to the PC 51, the boring data depth is associated with the excavation depth, and the accumulated current value based on the depth is “integrated current value” Is displayed in the display column 30 "(FIGS. 8 and 4).
[0121]
At this time, construction information (for example, construction method, excavation depth, excavation diameter, injection amount of curable material, etc.), construction machine information (for example, low speed base current value (Amp), low speed rotation speed (times / minute), high speed) Base current value (Amp), high-speed rotation speed (times / minute), etc.) are input. These data can also be switched and displayed on the screen 52 (not shown).
[0122]
(3) The pile driving machine 42 on which the excavation rod 1 is mounted is moved to a desired pile driving position (FIG. 11), and the excavation rod 1 is rotated forward (for example, clockwise) by the drive motor 40 via the wire 37. The auger machine 38 is gradually lowered along the leader 35. An excavation head 2 comprising a main body 6a and two excavation arms 6 and 6 is attached to the tip of the excavation rod 1, and when the excavation rod 1 rotates, the two excavation arms 6 and 6 open, The pile hole shaft is excavated by the excavating blades at the tips of 6 and 6 and the excavating blade at the lower end of the main body 6a (FIGS. 11 and 15B).
[0123]
At this time, the descending amount of the auger machine 38 is detected by the depth meter 45 as the excavation depth, and is initially set so that the depth is set to “0 (zero)” while the excavation blade of the excavation head 1 is in contact with the ground. Setting is performed (FIG. 15A). Further, the load current of the drive motor 40 is continuously detected by the load ammeter 44, and the measurement current at no load is set as the initial current.
[0124]
(4) By continuously lowering the auger machine 38, the ground is excavated while discharging water or the like from the tip of the excavating head 1, and the agitating drums 4 and 4 Kneaded to the inner wall 7a of the pile hole 7. At this time, the amount of water to be discharged is displayed on the screen 52 of the PC 51 by the flow meter 48 graphing the discharge amount for each depth.
[0125]
During excavation, the load on the drive motor 40 changes depending on the hardness of the ground, and the load current changes accordingly. Thereby, the load current value is accumulated at every predetermined excavation interval (for example, every 50 cm), the excavation time required for the excavation interval is calculated, and the N value of the boring data input in advance as an integrated current value, It is displayed together with the soil name at the same time as excavation with reference to the depth (FIGS. 5, 8, and 4). Since the accumulated current value draws an approximate curve with the N value, if the accumulated current value is different from the N value during excavation, it can be confirmed that there is a ground different from the boring and is appropriate during construction. Can take a good response.
[0126]
(5) The excavation is continued, and it is confirmed from the N value and the integrated current value displayed on the screen 52 of the PC that the support layer having the predetermined strength has been reached (FIGS. 5 and 8). After deep excavation, the excavation rod 1 is rotated in the reverse direction, and the excavation of the pile hole expansion root consolidation portion 9 is performed while the excavation rod 1 is pulled up. At the time of excavation of the enlarged solidification portion 9, the excavation rod 1 is rotated in the reverse direction, and the excavation arms 6 and 6 of the excavation head 2 are swung and expanded in the opposite direction to those at the time of normal excavation, so that an expanded excavation state is obtained. The enlarged solidified portion of the pile hole needs to be provided at a predetermined height (for example, 250 cm), but the position of the excavation head 2 is displayed on the screen 52 of the PC by the depth gauge 45 (FIGS. 6 and 4). Excavation of the enlarged root consolidation portion 9 having a predetermined height can be performed.
[0127]
(6) After forming the enlarged rooted portion 9 of the pile hole 7 having a predetermined size, the valve (not shown) is switched to switch the discharged material from water to cement milk. Cement milk is supplied into the pile hole from the discharge port 5 of the excavation head 2 through the pressure hose 47 from the plant 46.
[0128]
(7) In the “basic data display field 26”, “root hardening liquid injection amount display field 31” and “pile circumference fixed liquid injection amount display field 32” on the screen 52 of the PC 51, the root solid liquid and the pile circumference fixed previously input are displayed. The standard value of the liquid is displayed. In addition, the filling amount for each predetermined depth interval is graphed, and “flow rate / head position display column 28”, “integrated current value display column 30”, “rooting fluid injection amount display column 31”, “pile circumference fixing fluid” on the screen 52 are displayed. It is displayed in the “injection amount display column 32” (FIGS. 6, 9, 10, and 4), and the construction is performed while visually confirming whether cement milk of a standard value or more has been injected. At the same time, the actual usage amount of the root hardening liquid and the pile circumference fixing liquid is displayed together with the standard value in the “basic data display field 26” (FIG. 4).
[0129]
(8) First, cement milk as a solid solution (solidification strength 20 N / mm) in the enlarged root consolidation part 9 of the pile hole 7.²). While confirming the filling amount for each predetermined depth interval on the screen 52, the digging rod 1 (digging head 2) is rotated up and down repeatedly in the enlarged root consolidation portion 9, and stirred and mixed with the excavated soil. Solidified layer 13 (soil cement layer. Solidification strength 20 N / mm²Above).
[0130]
At this time, if the amount of cement milk does not exceed the standard value, the cement milk is reinjected at the relevant depth.
[0131]
(9) Construction of the root consolidation layer 13 in the above, that is, injection of cement milk in the enlarged root consolidation portion 9 of the pile hole 7 is performed in order to reduce variation in the quality of the soil cement in the root consolidation layer 13. It is desirable to perform the same as in the first embodiment.
[0132]
That is, after the excavation of the pile hole 7 is completed, the total amount of cement milk as root solid liquid is obtained from the discharge port 5 at the lower end of the excavation head 2 while stirring the excavation head 2 while the excavation head 2 is held at the pile hole bottom 10. Discharge cement milk addressed to one third. Subsequently, while agitating with the excavation head 2, the excavation rod 1 is raised to the vicinity of the upper end portion 15 of the enlarged rooting portion 9 of the pile hole 7, and one third of the total amount of cement milk is discharged. Next, the excavation head 2 is moved up and down a plurality of times in the enlarged rooting part 9 (between the bottom 14 of the pile hole 7 and the upper end part 15 of the enlarged rooting part 9), while remaining 3 minutes of the remaining cement milk. 1 is discharged, stirring and mixing are performed, and the excavation rod 1 is pulled up to form a root hardening layer 13 made of a soil cement layer in the enlarged root hardening portion 9 (FIG. 3 (b), Case 2).
[0133]
Even in such a complicated construction, the positions of the rooting liquid (cement milk) and the excavation head 2 can be determined by the “flow rate / head position display field 28”, “rooting liquid injection amount display field 31”, etc. on the screen 52. It can be performed while visually confirming, and fine construction management can be performed very easily and reliably.
[0134]
(10) Further, another desirable method for injecting cement milk is to place the discharge port 5 of the excavation head 2 at substantially the center of the bottom of the enlarged rooting portion 9 of the pile hole 7 (the bottom portion of the rooting layer to be constructed). Install and reciprocate up and down two times in the enlarged root-setting part 9 while stirring and discharging to complete the injection at the upper end part 15 (FIG. 3 (c), Case 3).
[0135]
Further, the entire amount of cement milk is injected from the discharge port 5 of the excavation head 2 at the bottom 10 of the enlarged root consolidation part 9 to push up the excavation mud in the enlarged root consolidation part 9 and replace the excavation mud with cement milk. It is also possible to form an expanded root hardening layer 13 composed of a cement milk layer (FIG. 3 (d), Case 4).
[0136]
(11) Next, cement milk is poured into the enlarged root consolidation portion 9 and after the construction of the root consolidation layer 13 is completed, the excavation rod 1 is returned to the normal rotation, the excavation head 2 is brought into a normal excavation state, and Pile circumference fixing liquid (solidification strength 20 N / mm) in the shaft portion 8 of the pile hole 7²) Start infusion. Regarding the pile circumference fixing liquid, similarly to the injection of the root solid liquid, the filling amount for each predetermined depth interval is set as the standard quantity, “flow rate / head position display field 28” on the screen 52 of the PC 51, “pile circumference fixed liquid injection amount display” While comparing and confirming in "Column 32", the pile periphery fixed liquid layer 16 (solidification strength 2N / mm) which consists of a soil cement layer in the axial part 8 of the pile hole 7 is confirmed.²Above). At this time, if the standard filling amount is not satisfied, re-injection is performed at the corresponding depth in the same manner as the root solid liquid.
[0137]
(12) The cement milk injection method in the shaft portion 8 of the pile hole 7 described above, that is, the formation of the pile circumference fixing liquid layer (soil cement layer) 16 is also higher than the position of the upper end portion 15 of the root hardening layer 13. Then, according to the excavation length, one or a plurality of predetermined depths are determined, and cement milk injection is started from the upper end portion 15 of the root-solidifying layer 13, and the reciprocation is repeated between the predetermined depths. The pile circumference fixed layer 16 is formed while mixing.
[0138]
Regarding the management of the filling amount of the pile circumference fixing liquid (cement milk), the average value of the amount of cement milk injected at every predetermined depth interval is calculated in a certain range (for example, every 1 m) of the shaft portion 8 of the pile hole 7. If the average value exceeds the standard filling amount, the construction can be appropriate.
[0139]
(13) Subsequently, after the cement milk is filled more than the reference filling amount, a ready-made pile composed of an upper pile, a middle pile and a lower pile is inserted and the foundation pile 24 is constructed as in the first embodiment.
[0140]
The excavation head 2 is removed from the excavation rod 1 and a rotation cap is attached. First, “BF6075-5m” ready-made pile (lower pile) 20 (shaft diameter: φ600, nodal diameter: φ750, nodal pile) (“BF” is Mitani A trademark of SEXAN CO., LTD. (Hereinafter the same) is attached to a rotating cap, and is placed in a pile hole 7 filled with soil cement while rotating. Next, “SCφ600-14m” ready-made pile (middle pile) 22 is connected and set, and thereafter “SCφ600-15m” ready-made pile 22 and “SCφ600-15m” ready-made pile (upper pile) 22 are connected in the same manner. The tip 21 of the “BF6075-5m” ready-made pile 20 at the tip of the connecting pile is pushed and embedded at a position of about 50 cm from the bottom 14 of the enlarged root-sealed layer 13 to complete the embedding of the ready-made piles 20, 22, 22 ( FIG. 2 (c) (d)). After the soil cement is solidified, a foundation pile 24 in which the ready-made piles 20, 22, 22, the root hardening layer 13, and the pile circumference fixing liquid layer 16 (soil cement) are integrated in the pile hole 7 is constructed.
[0141]
Further, in the “pile tip position display field 29” of the screen 52 of the PC 51, the burying time of the ready-made piles 20 and 22 is recorded, and the position of the tip 21 of the ready-made pile 20 is recorded. , 22 can be confirmed for each construction of each foundation pile 24, and can also be used as guarantee data for construction contents (FIGS. 4 and 7).
[0142]
[Example 4]
Next, construction when the pile length is long (for example, about 50 m) will be described with reference to FIGS. 16, 17, and 14 (FIG. 14).
[0143]
When the pile length becomes long (for example, 50 m), the leader 35 of the pile driving machine 42 is usually about 20 m, and the length is limited. Therefore, another rod (from the excavation rod 1 is attached to the upper end of the excavation rod 1. The lower end of the structure (with the excavation head 2 removed) is connected, and the upper end of the other rod is attached to the auger machine 38 to continue excavation.
[0144]
Conversely, when the pile hole excavation is completed and cement milk is injected and the excavation rod 1 is pulled up from the pile hole 7, the length of the leader 35 of the pile driving machine 42 is limited. The injection was interrupted, and the other rod 25 had to be separated from the excavation rod 1 by a predetermined length.
[0145]
That is, construction is performed according to the following procedure. The method for injecting cement milk and the method for burying the foundation piles 20 and 22 are the same as those in Examples 2 and 3.
[0146]
(1) One pile core A side
[0147]
As in the third embodiment, the excavation rod 1A attached to the auger machine 38 of the pile driving machine 42 excavates the upper part of the shaft portion 8A of the pile hole 7A to a predetermined depth, and then the excavation rod 1A is used as the auger machine. The upper end 1a of the excavation rod 1A is temporarily supported above the pile hole 7A. The lower end 25b of the other excavation rod 25 is connected to the upper end 1a of the excavation rod 1A, and the upper end 25a of the other excavation rod 25 is connected to the auger machine 38 to expand the remaining (lower) pile hole shaft portion 8A. The root consolidation part 9A is excavated (FIG. 16, FIG. 17 (a)).
[0148]
Subsequently, cement milk is discharged from the discharge port 5A of the excavation head 2A of the excavation rod 1A to form the root hardening layer 13A. Subsequently, while lifting the excavating rod 1A and the rod 1a, cement milk is similarly discharged from the discharge port 5A to form the lower portion of the pile circumference fixing liquid layer 16A.
[0149]
In this state, the upper end portion 1a of the excavation rod 1A appears on the ground 18, so that the upper end portion 1a of the excavation rod 1A is temporarily supported above the pile hole 7A. At the same time, the other excavation rod 25 is removed from the excavation rod 1A (FIGS. 16A-1 and 17B). The pile hole excavation data on the one pile core A side up to this state is managed by the same management device as in the third embodiment, and the management content up to that point is stored and stored in the PC 51. A pile number is assigned to the pile core A, and since this pile number is stored in the PC 51, it can be easily read and stored.
[0150]
(2) The other pile core B side
[0151]
The excavation rod 1A to which the excavation head 2A is attached at the tip is retained in the pile hole 7A as it is.
[0152]
The other excavation head 2B is attached to the tip of the other excavation rod 25 attached to the auger machine 38 of the same pile driving machine 42 (FIG. 17 (c)). On the side, excavation of the pile hole 7B is started (FIG. 16 (B-1)). At this time, the construction management is performed in the same manner as in the third embodiment (similar to the pile hole 7A) as the construction management of the pile hole 8B, separately from the stored management on the pile hole 7A side. That is, by one pile driving machine 42, one of the two pile cores (pile burying positions) A and B is subjected to a cement milk filling process and the other a drilling process.
[0153]
Similarly, with the other excavation rod 25 excavating the upper portion of the shaft portion 8B of the pile hole 7B (FIG. 17 (d)), the upper end 1a of the excavation rod 1B is temporarily supported above the pile hole 7B, and the auger The other excavation rod 25 is removed from the machine 38 (FIG. 16 (B-2), FIG. 17 (e)).
[0154]
The above management content is temporarily stored in the storage device in the amplifier box 50 or the PC 51 as the management content on the pile core B side. Moreover, since the pile number is attached | subjected also about the pile core B, it can display on the screen 52 of PC of PC51 alternately or simultaneously with the pile hole 7A.
[0155]
(3) One pile core A side
[0156]
The other excavation rod 25 to which the other excavation head 2B is attached at the tip is retained in the pile hole 7B as it is.
[0157]
The pile driving machine 42 is moved to the vicinity of the pile core A, and the upper end portion 1a of the excavating rod 1A held in the pile hole 7A is connected to the auger machine 38 (FIG. 17 (f)). The management information on the pile core A side temporarily stored in the storage device in the amplifier box 50 or the PC 51 is read, and the temporary support of the excavation rod 1A is released.
[0158]
Cement milk is discharged from the discharge port 5A of the excavation rod 1A, and the excavation rod 1A is pulled up while forming the upper part of the pile circumference fixed liquid layer 16A. At this time, if necessary, the discharge of cement milk can be started after the excavating rod 1A is slightly lowered downward. Also in this case, the position of the excavation head 2 </ b> A is measured by the depth meter 45.
[0159]
If the excavation rod 1A is pulled out from the pile hole 7A (FIG. 17 (g)), the pile hole 7A in which the root hardening layer 13A and the pile circumference fixing liquid layer 16A are formed is constructed (FIG. 16 (A-2)). .
[0160]
Hereinafter, similarly, the excavation rod 1A is removed from the auger machine 38 of the pile driving machine 42, the ready-made piles 20 and 22 are embedded, and the foundation pile 24 is constructed on the pile core A.
[0161]
(4) The other pile core B side
[0162]
The pile driving machine 42 is moved to the vicinity of the pile core B, and the lower end of the excavation rod 1B is connected to the upper end of another excavation rod 25 held in the pile hole 7B, and the upper end of the excavation rod 1B is piled. It connects with the auger machine 38 of the machine 42 (FIG.17 (h)). The management information on the pile core B side temporarily stored in the storage device in the amplifier box 50 or the PC 51 is read, and the temporary support of the excavation rod 1B is released.
[0163]
Although the excavation rod 1B is used here, the excavation rod 1A (FIG. 17 (g)) that has been removed can be used as it is in the construction on the pile core A side (not shown).
[0164]
Similarly, in the state where the lower part of the pile hole shaft 8B and the pile hole widened part 9B are excavated (FIG. 17 (i)) and the lower part of the root consolidation layer 13B and the pile peripheral fixed liquid layer 16B is formed, FIG. Similarly to A-1), the excavation rod 1B is temporarily held above the pile hole 7B (not shown).
[0165]
In this state, the management information on the pile core B side is temporarily stored again in the storage device in the amplifier box 50 or the PC 51.
[0166]
(5) Then, similarly to the pile core B, construction is performed on the other pile core C side.
[0167]
Thus, since the pile management number is assigned to each pile core and the construction management status is stored, the construction management display of one pile core A is temporarily stored in the storage device in the amplifier box 50 or the PC 51. The construction management status of the other pile core B can be displayed, the construction management status of the other pile core B can be temporarily stored, the construction management status of one pile core A is read again, and cement milk is injected. Is completed, and if necessary, the construction management status up to the completion of pile burial can be displayed.
[0168]
Therefore, the foundation pile can be constructed by efficiently using even a few pile driving machines 42. Even in this case, the same construction management can be performed.
[0169]
【The invention's effect】
In this invention, the cement milk to be injected is divided into a plurality of times, and the cement milk is injected while moving the cement milk discharge port up and down at least twice in the bottom of the pile hole. It is stable with little variation in outer diameter and variation in compressive strength, and it can be formed uniformly and has the effect of improving the quality of the root hardening layer. Therefore, a strong root-solidifying layer can be formed, and a high supporting force corresponding to the diameter of the pile hole can be exhibited by the foundation pile and the solidified body integrated with the foundation pile. It can also be expected that this can be prevented with respect to the initial settlement before solidification of the root hardening layer.
[0170]
Furthermore, as a device for agitating the inside of the root consolidation layer, various excavation devices such as an excavation head and an auger machine when excavating the root consolidation layer can be used as they are so that a homogeneous layer having a high bearing force can be formed. Since the stirring conditions could be established, simple and economical stirring and mixing could be performed without preparing a new stirring device.
[0171]
In particular, when discharging to 1/3 of the total amount of cement milk at the bottom of the pile hole, these components with low specific gravity are used even if components that are not good for the geology of the supporting ground remain in the pile hole. Cement milk can be pushed up and ejected, and a stable and high quality rooting layer can be obtained.
[0172]
According to the management method or the management device of the present invention, when excavating a pile hole, the load current borne by the auger is converted into an integrated current value and displayed at the same time as excavation. When confirming and subsequently injecting cement milk, the filling amount at every predetermined depth interval is displayed at the same time as the injection, so that the injection status can be confirmed and the construction accuracy of the foundation pile can be improved consistently. effective.
[0173]
By processing and displaying the injection status at the same time as the injection with an information processing means such as a personal computer, there is an effect that the cement milk at every predetermined depth interval can be reliably injected more than the reference amount according to the depth.
[0174]
Since a certain amount or more of cement milk can be injected at predetermined depth intervals in the pile hole, it is possible to obtain necessary and stable support force according to the depth, and imbalance of support force between adjacent foundation piles at the construction site There is an effect that can be suppressed as much as possible.
[0175]
In addition, in the construction management, the information processed by the information processing means can be displayed and stored one by one, so that the operator can use one pile driver without confusion about the construction conditions for each pile hole. Even when one pile hole is divided and the adjacent pile holes are constructed alternately, it is possible to continue using the temporarily stored data in the middle of construction as it is, so construction can be built. There is an effect of increasing the efficiency.
[Brief description of the drawings]
FIGS. 1A to 1D are longitudinal sectional views illustrating a cement milk injection method according to an embodiment of the present invention.
FIGS. 2A to 2D are longitudinal sectional views for explaining a cement milk injection method according to an embodiment of the present invention. FIG.
FIGS. 3A and 3B are graphs of “cement milk discharge amount-depth” for explaining the discharge specifications of cement milk. FIGS. 3B and 3C show the specifications of the present invention, and FIGS. To express.
FIG. 4 is an example of construction data display during excavation used in the embodiment of the present invention.
5 is an enlarged view of the “N value display column” of the construction data in FIG. 4, and is a graph in which the vertical axis indicates depth and the horizontal axis indicates N value.
6 is an enlarged view of the “flow rate / head position display column” of the construction data in FIG. 4, and is a graph with depth or flow rate on the vertical axis and time required for construction (minutes) on the horizontal axis.
7 is an enlarged view of the “pile tip position display field” in the construction data of FIG. 4, where the vertical axis indicates the pile tip position (depth), and the horizontal axis indicates the required time (minutes) since the start of pile insertion. It is a graph.
8 is an enlarged view of the “integrated current value display column” of the construction data in FIG. 4, and is a graph in which the vertical axis indicates depth and the horizontal axis indicates the integrated current value.
9 is an enlarged view of the “root filling liquid injection amount display column” of the construction data in FIG. 4, and is a graph in which the vertical axis indicates the depth of the root hardening portion and the horizontal axis indicates the root hardening liquid injection amount.
10 is an enlarged view of the “pile circumference fixed liquid injection amount display column” of the construction data in FIG. 4, and is a graph in which the vertical axis indicates depth and the horizontal axis indicates the pile circumference fixed liquid injection amount.
FIG. 11 is a front view of a pile driving machine used for carrying out the present invention.
FIG. 12 is a diagram showing the configuration of an embodiment of the construction management device according to the present invention.
FIG. 13 is a flowchart of an embodiment of the construction management method of the present invention.
FIG. 14 is a flowchart of another embodiment (embodiment 4) of the construction management method of the present invention.
FIG. 15 is a longitudinal sectional view for explaining the construction method of the present invention.
FIG. 16 is a longitudinal sectional view for explaining a construction method according to Embodiment 4 of the present invention;
FIGS. 17A to 17I are schematic longitudinal sectional views for explaining the construction method of the fourth embodiment.
18A is an enlarged front view and FIG. 18B is a partially enlarged side view with a part broken away; FIG.
[Explanation of symbols]
1 Drilling rod
2 Drilling head
3 Stir bar
4 Kneading drum
5 Discharge port
6 Drilling arm
7 Pile hole
7a Pile hole inner wall
8 Shaft hole shaft
9 Expanded root consolidation part of pile hole
10 Bottom (enlarged root)
11 Upper edge
12 Pile hole
13 Rooting layer
14 Bottom (root hardening layer)
15 Upper end (root hardening layer)
20 Ready-made piles
21 Tip of ready-made pile
22 Ready-made piles
24 Foundation pile
26 Basic data display field
27 N value display field
28 Flow rate / head position display field
29 Pile tip position display field
30 Integrated current value display field
31 Root hardening liquid injection amount display column
32 Pile circumference fixed liquid injection amount display column
38 auger machine
40 Drive motor (for auger machine)
41 Unwinding device (pile driver)
42 Pile driver
44 Load ammeter
45 Depth meter
46 plants
47 Pressure hose
48 Flowmeter
50 Amp Box
51 Personal computer (PC)
52 PC screen
53 printing press
55 Operator room
57 Drilling arm tip
58 Drilling blade of drilling arm

Claims (6)

A root consolidation layer is formed at the bottom of the pile hole, and a pile periphery fixing liquid layer is formed within the pile hole shaft, and the ready-made pile is buried in the pile hole, and the lower end of the ready-made pile is fixed in the consolidation layer. In the construction of the foundation pile, in the method of injecting cement milk into the bottom of the pile hole to construct the rooting layer , a discharge port is formed at the lower end of the excavation rod having the excavation head,
(1) After excavating the pile hole, hold the excavation head at the bottom of the pile hole, and discharge the cement milk addressed to one third of the total amount of cement milk to be injected from the discharge port;
(2) Next, while raising the excavating rod to the vicinity of the upper edge of the root consolidation layer to be formed, one third of the total amount of cement milk is discharged, and the strength in the root consolidation layer is not good. The object is pushed up above the rooting layer,
(3) Next, while raising and lowering the excavation rod a plurality of times between the bottoms of the pile holes, the remaining cement milk is discharged, and the excavation rod is pulled up to form a solidified layer.
A method for constructing a pile hole consolidation layer characterized by that. The cement milk injection status for "root- setting liquid or pile circumference fixing liquid" is displayed on the display device installed in the construction operation room, construction machine, or construction control room in the construction area, and the surrounding ground and pile holes are built. While confirming the state, inject cement milk, and display the display device,
, The horizontal axis is the time from the start of construction, and the vertical axis is "flow rate per hour of the rooting liquid or pile circumference fixing liquid obtained from the flow meter", "total discharge flow rate obtained from the flow meter" and "depth" construction method of the excavating head position "a pile hole roots solidified layer of claim 1, wherein that said <br/> be graphed simultaneously displayed obtained from meter. A rotary drive device for mounting the excavation rod or the ready-made pile, an elevating means for raising and lowering the rotary drive device, and a liquid supply means for supplying water or " cement milk or pile circumference fixing liquid" to the excavation rod In the pile driving device comprising the various sensors, comprising the various sensors, collectively processing the information from the various sensors, displaying the information on the screen and storing and recording information.
(1) The various sensors measure a load ammeter that measures the load current of the rotary drive device and a depth position of the excavation rod or the ready-made pile from the ground by sensing the amount of lift of the rotary drive device. A depth meter, and a flow meter for measuring the amount of liquid supplied from the liquid supply means,
(2) The information processing means displays the data from the flow meter for each depth set from the data from the depth meter, and sets a predetermined flow rate and an actual flow rate for each preset depth. A function for displaying in comparison with a function for accumulating and displaying data from the load ammeter for each predetermined depth, and for comparing and displaying the corresponding N value data for each predetermined depth. And the function of reading out, displaying, storing and accumulating the information for each pile hole .
(3) The display of data by the information processing means, the horizontal axis is the time from the start of construction, and the vertical axis is "flow rate per hour of water, rooting liquid or pile circumference fixing liquid obtained from a flow meter", " The “total discharge flow rate obtained from the flow meter” and the “excavation head position obtained from the depth meter” are graphed and displayed simultaneously.
A construction management device for foundation piles. Forming a discharge port at the lower end of a drilling rod having a drilling head;
When injecting cement milk into the pile hole consolidation layer ,
(1) After excavating the pile hole, hold the excavation head at the bottom of the pile hole, and discharge the cement milk addressed to one third of the total amount of cement milk to be injected from the discharge port;
(2) Next, while raising the excavating rod to the vicinity of the upper edge of the root consolidation layer to be formed, one third of the total amount of cement milk is discharged, and the strength in the root consolidation layer is not good. The object is pushed up above the rooting layer,
(3) Next, while raising and lowering the excavation rod a plurality of times between the bottoms of the pile holes, the remaining cement milk is discharged, and the excavation rod is pulled up to form a solidified layer.
The construction management apparatus for foundation piles according to claim 3 . A rotary drive device for mounting the excavation rod or the ready-made pile, an elevating means for raising and lowering the rotary drive device, and a liquid supply means for supplying water or cement milk for “root- setting liquid or pile circumference fixing liquid” to the excavation rod; Construction comprising a drilling process for excavating a pile hole using a pile driving machine equipped with, an injection process for injecting cement milk into the pile hole, and a pile insertion process for burying a ready-made pile in the pile hole into which cement milk has been injected A method of managing methods,
Depth for measuring the depth position from the ground of the excavation rod tip or ready-made pile tip by sensing the data from the load ammeter that measures the load current of the rotary drive and the amount of lift of the rotary drive Data from the total,
Calculate and process data from a flow meter that measures the amount of liquid supplied from the liquid supply means, and store these data so that they can be read for each pile hole,
For each pile hole,
(1) In the excavation process, the data from the load ammeter is accumulated and displayed for each predetermined depth, and displayed in comparison with the corresponding N value data for each predetermined depth, Check the support layer.
(2) In the injection process, the horizontal axis is the time from the start of construction, and the vertical axis is "flow rate per hour of water, rooting liquid or pile circumference fixing liquid obtained from the flow meter", "discharge obtained from the flow meter. The total flow of the object and the position of the excavation head obtained from the depth gauge are graphed and displayed simultaneously,
The prescribed flow rate at each depth set in advance and the actual flow rate are compared and displayed, and the amount of cement milk at each depth is managed.
(3) In the pile insertion process, the pile tip position is managed from the data from the depth gauge, and it is managed that the ready-made pile is fixed on the support layer.
A construction management method for foundation piles characterized by that. When forming the discharge port at the lower end of the drilling rod with the drilling head and injecting cement milk into the pile hole consolidation layer,
(1) After excavating the pile hole, hold the excavation head at the bottom of the pile hole, and discharge the cement milk addressed to one third of the total amount of cement milk to be injected from the discharge port;
(2) Next, while raising the excavating rod to the vicinity of the upper edge of the root consolidation layer to be formed, one third of the total amount of cement milk is discharged, and the strength in the root consolidation layer is not good. The object is pushed up above the rooting layer,
(3) Next, while raising and lowering the excavation rod a plurality of times between the bottoms of the pile holes, the remaining cement milk is discharged, and the excavation rod is pulled up to form a solidified layer.
The construction management method for a foundation pile according to claim 5, characterized in that it is a feature.

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