JP2004163320A - Device for controlling perpendicularity of pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure a correct piling without being affected by worker's skill even though an arm 5 is bent while working. <P>SOLUTION: An arm flexure correcting means 32 calculates true linear line length Lt from hinge part 6 to the top of the arm 5 and a true inclination angle θt made by true linear line length Lt and the horizontal surface, by using difference between the inclination angles θ2' and θ3' detected by an arm clinometers 29, 31, and bending length L of the arm 5. The objective arm length Ln from the hinge part 6 to the top of the arm 5 is calculated from the true inclination angle θt, and the rod distance L2 which is the distance from the hinge part 6 to the center line 15 of the pile when the center line 15 of the pile is coincide with the vertical line of the piling point P. <P>COPYRIGHT: (C)2004,JPO

Description

【００３８】
このロッド距離Ｌ２は、杭芯距離算出手段３９から表示器３６に出力され、データ数字表示部７２に常時表示される。
【００３９】
こうして杭芯１５の基準姿勢を記憶し、ロッド距離Ｌ２を算出したら、アーム５の先端に杭芯１５を装着し、アーム角度動作ボタン７５を押して、アーム５を任意の高さまで引上げる（ステップＳ５）。このときの表示器３６の表示形態を図７に示す。ステップＳ２で杭芯検出ボタン７３に手を触れると、この杭芯検出ボタン７３に位置する表示色が別のものになる。これにより、オペレータは杭芯１５の基準姿勢がすでに記憶されていることを目視で直接確認できる。また、杭芯１５の長さが判っていれば、それを操作部３７から入力すれば、演算処理部３５はアーム５の先端が杭芯１５の長さに引上げられるまでの引上げ角度を自動的に算出できる。したがって、アーム角度動作ボタン７５を構成する「自動」ボタンを押したときに、この引上げ角度に自動的にアーム５が引上げるように制御手段である演算算出部３５を構成すれば、オペレータの熟練度に左右されず簡単にアーム５を作業開始位置にまで引上げることができる。
【００４０】
アーム５の引上げ時には、貫入位置Ｐの垂直線上にアーム５の先端が位置するアーム５の目標長さＬｎが目標アーム長さ算出手段４１で算出され、これが表示器３６の目標アーム長表示部５２に表示される。この目標アーム長さＬｎは、アーム撓み補正手段３２から算出される現時点でのアーム５の角度θと、前記ロッド距離Ｌ２に基づき、次の数式にて算出される。
【００４１】
【数２】

【００４２】
オペレータは、枢着部６を中心にアーム５を回動させて引上げながら、現在アーム長表示部５２に表示される現在のアーム５の長さＬ１が、この目標アーム長さＬｎの許容範囲内に入るように、アーム伸縮動作ボタン７６を操作してアーム５を伸縮させる（ステップＳ５）。そして、現在のアーム長さＬ１が目標アーム長さＬｎに一致すれば、下端を貫入位置Ｐに合わせた杭芯１５は鉛直な状態となり、杭芯１５の垂直な軌跡上にアーム５の先端が位置する。なお、このとき深度表示部７４には、アーム撓み補正手段３２で算出された現在のアーム長Ｌ１と、アーム角度θを基にして、演算処理部３５で算出されたアーム５の引上げ長さが表示される。
【００４３】
こうして、アーム５を引上げた後、アーム５の先端が貫入位置Ｐを押した状態で、アーム５が鉛直になっていることを確認したら、ステップＳ６に移行して、施工開始を指示するために再度施工開始ボタンでもある杭芯検出ボタン７３に手を触れる。これにより演算処理部３５は、アーム５が杭入施工作業の開始位置にあるものと判断して、そのときアーム撓み補正手段３２で得られるアーム５の開始角度θ０と開始長さＬ０を、施工開始アーム位置記憶手段４０にそれぞれ記憶すると共に、この開始角度θ０と開始長さＬ０を基に、杭芯距離算出手段３９はロッド距離Ｌ２を再度次の数式にて算出する。
【００４４】
【数３】

【００４５】
このロッド距離Ｌ２は、施工開始アーム位置記憶手段４０に記憶されると共に（ステップＳ７）、施工作業が終了するまで不変である。そして、前記数２における角度θにアーム５の開始角度θ０を代入することで、目標アーム長さＬｎを算出して、これを目標アーム長表示部５２に表示する。
【００４６】
なお、施工開始時は杭芯１５の先端を貫入位置Ｐに一致させるため、軟弱地盤１に杭芯１５の先端を押し付ける力がアーム５から加えられている。そのため、アーム５は後述する杭芯１５の貫入時ほどではないにせよ、多少の反発力が加わり撓んでいる。したがって、目標アーム長さＬｎを正しく算出するために、アーム撓み補正手段３２を利用して、アーム５が撓んでいないと仮定したときのアーム５の開始角度θ０と開始長さＬ０を算出している。
【００４７】
図８は、杭入施工作業の開始時における表示器３６の表示形態を示したものである。ここでは、アーム角度表示部５１に補正された現在のアーム５の角度θ（施工開始時は開始角度θ０）が表示され、目標アーム長表示部５２にその角度θにアーム５が向けられているときの目標アーム長さＬｎが表示され、アーム長表示部５３に現在のアーム長さＬ１（施工開始時は開始長さＬ０）が表示され、深度表示部７４には杭芯１５の先端の深度Ｈが表示される。この深度Ｈは、アーム５の開始長さＬ０から、現在のアーム長さＬ１と、アーム５の開始角度θ０から現時点でのアーム５の角度θを差し引いた動作角度θ１とにより、余弦定理を利用した次の数式から算出される。
【００４８】
【数４】

【００４９】
上記数式より、杭芯１５の下端が軟弱地盤１に貫入していない作業開始時には、アーム長・アーム起伏角補正演算手段３２により補正された現在のアーム長さＬ１と角度θが、アーム５の開始長さＬ０と開始角度θ０にそれぞれ一致しており、上記数式により算出された深度Ｈも０となる。なお、表示器３６のデータ数字表示部７２には、前記作業開始時におけるアーム５の開始角度θ０と、アーム５の現在の動作角度θ１と、アーム５の開始長さＬ０と、現在のアーム長さＬ１と、ロッド距離Ｌ２がそれぞれ表示される。
【００５０】
これ以降は、通常の地盤改良工事が行なわれる。とりわけ杭芯１５により軟弱地盤１を掘削するに際しては、前記施工開始アーム位置記憶手段４０に記憶した各データを基に、施工中における杭芯１５の深度Ｈと垂直度の算出が行なわれる。具体的には、杭芯１５による掘削が進み、アーム５の角度を下げる操作を例えばアーム角度動作ボタン７５で行なうと、目標アーム長さ算出手段４１は、アーム撓み補正手段３２から得られる現在のアーム５の角度θと、施工開始時に算出したロッド距離Ｌ２から、杭芯１５が鉛直を維持する目標のアーム長さすなわち目標アーム長さＬｎを算出し、これを目標アーム長表示部５２に表示させる。このとき図９に示すように、現在のアーム長さＬ１が、目標アーム長さＬｎの許容範囲（例えば、±０．１０ｍ）を外れている場合には、補正された現在のアーム長さＬ１を表示する現在アーム長表示部５３の表示色が変わって例えば赤色に反転する。オペレータはこれを見て、杭芯１５が垂直に貫入されるように、アーム５の長さを調節操作して、補正された現在のアーム長さＬ１を目標アーム長さＬｎに一致させる（ステップＳ８）。なお、このとき杭深度算出手段４２により算出される深度Ｈは、補正された現在のアーム長さＬ１が目標アーム長さＬｎからずれているため、正しく深度表示部７４に表示されない。
【００５１】
アーム５の長さを正しく調節したときの表示器３６の表示状態を示したのが、図１０である。この場合、現在アーム長表示部５３に表示される現在のアーム長さＬ１が、目標アーム長表示部５２に表示される表示目標アーム長さＬｎと一致しており、杭芯１５は貫入位置Ｐを垂直に貫入している。また、深度表示部７４に表示される杭芯１５の深度Ｈも正しい値となる。演算処理部３５のデータ送信手段４４は、現在のアーム長さＬ１が目標アーム長さＬｎの許容範囲内にあるときの正しい杭芯１５の深度Ｈを、他のデータと共にセンターに送出するので、杭芯１５が鉛直でない状態の誤った深度Ｈのデータ収集を未然に防ぐことができる。そして、このようなアーム５の長さ調節を繰り返せば、杭芯１５を常時ほぼ垂直な状態で貫入位置Ｐに貫入させることが可能になると共に、正しい深度Ｈのデータ収集が可能になる。
【００５２】
続いて図１１に基づき、パラメータ画面切換ボタン７８を押したときに表示器３６に表示されるパラメータ設定画面について説明する。ここでは、表示項目であるサンプリング区間，サンプリングタイマー，アーム許容範囲などの各種設定値を表示するパラメータ値表示部８１と、現在時刻の設定を変更する現在時刻設定表示部８２がそれぞれ設けられる。また、前述の図６〜図１０に示す垂直施工支援画面を表示するための垂直施工支援切換ボタン８３と、図１１とは別のパラメータ設定画面を表示するためのパラメータ画面切換ボタン８４と、図５のメイン表示画面に戻るボタン８５も、それぞれ表示器３６上にあるタッチパネルの操作部３７として設けられる。
【００５３】
このなかで、パラメータ値表示部８１に表示されるサンプリング区間とは、演算処理部３５が収集する各施工データの収集タイミングを設定するもので、この値は任意（例えば１ｍで割り切れる値）に変更できる。また、サンプリングタイマーとは、前記深度Ｈが変化しない状態が設定時間（この場合は１５秒）続いた場合に、サンプリング区間に深度Ｈが変化しなくても、優先してデータ収集を行なう。なお、有効ボタン８６を操作することで、この機能を無効にすることもできる。さらに、アーム許容範囲とは、前述の杭芯１５を垂直に保つために算出した目標アーム長さＬｎの許容範囲を設定するもので、この値を設定することで、誤った深度Ｈのデータ収集を未然に防ぐことができる。
【００５４】
また別な変形例として、前記図１２に示すステップＳ１からステップＳ５の各手順を省いて、ステップＳ６以降の杭芯１５を施工開始位置にセットした状態から作業を行なってもよい。これは図１２の点線で示される。
【００５５】
次に、上記一連の手順において、アーム撓み補正手段３２についての動作を詳細に説明する。図３に示すように、杭芯１５を軟弱地盤１に貫入する施工作業中は、杭芯１５を軟弱地盤１中に押し込む力と、杭芯１５が軟弱地盤１から受ける反発力が、アーム５並びに建柱車２を押し上げる力として作用し、アーム５自身が撓むと共に、建柱車２の前方も浮き上がる。図４は、撓みが生じたアーム５の状態を示す説明図で、本実施例のようなアーム５では、第一アーム可動部１２が出没するアーム基部１１の先端と、第二アーム可動部１２が出没する第一アーム可動部１２の先端が、それぞれ折れ曲がった状態で撓んでいる。なお同図において、ｌ１はアーム基部１１のアーム長、ｌ２は第一アーム可動部１２のアーム長、ｌ３は第二アーム可動部１３のアーム長で、これらはいずれも直線長さである。また、ｌ４は杭芯１５の基端を取付けるのに必要な第二アーム可動部１３の先端固定長で、この部分は第二アーム可動部１３を最も縮めた状態であっても、第一アーム可動部１２の先端よりも外方に突出している。
【００５６】
Ｌｔはアーム５の枢着部６からアーム５の先端までの直線上の長さである真の直線長さで、θｔはこの真の直線長さＬｔと水平面との成す角度である真の起伏角度である。θ２はアーム基部１１と水平面との成す角度で、θ３は第二アーム可動部１３と水平面との成す角度であり、ｌｘは第一アーム可動部１２の基端から第二アーム可動部１３の先端に至る長さである。θｕは第一アーム可動部１２と長さｌｘとの成す角度で、θｗは真の直線長さＬｔとアーム基部１１との成す角度であり、θｓはアーム基部１１に対する第一アーム可動部１２の撓み角（外角）で、この場合は、第一アーム可動部１２と第二アーム可動部１３が同じ量だけ出没する関係で、第一アーム可動部１２に対する第二アーム可動部１３の撓み角（外角）も同じθｓであると仮定している。さらに、θｙは第一アーム可動部１２と第二アーム可動部１３との成す角度（内角）で、θｚはアーム基部１１と長さｌｘとの成す角度（内角）である。
【００５７】
上記構成において、アーム撓み補正手段３２は、アーム５の真の直線長さＬｔおよびアーム５の真の起伏角度θｔを算出する。そのために、まず打設中において、いずれも車両本体３の浮き上がりによる影響を含んだアーム傾斜計２９から得られるアーム基部１１の水平面に対する角度θ２’と、アーム傾斜計３１から得られる第二アーム可動部１３の水平面に対する角度θ３’とをそれぞれ取り込むと共に、打設開始時に予め記憶された車両傾斜計３０からの車両本体３の車体傾斜角度と、打設中において車両傾斜計３０から出力される車両本体３の車体傾斜角度との差を、角度差θ４Δとして算出する。
【００５８】
そして、車両本体３の浮き上がりによる影響を取り除いた打設中のアーム基部１１の正確な角度θ２と、第二アーム可動部１３の正確な角度θ３は、次の数式に示すように、アーム傾斜計２９で得られる角度θ２’と、アーム傾斜計３１で得られる角度θ３’から、それぞれから前記角度差θ４Δを差し引くことで算出される。
【００５９】
【数５】

【００６０】
【数６】

【００６１】
なお、アーム５の開始長さＬｏと開始角度θ０を算出する際には、車両本体３はさほど浮き上がっていない。また、施工中も車両本体３がさほど浮き上がらない場合には、アーム傾斜計２９で得られる角度θ２’と、アーム傾斜計３１で得られる角度θ３’を、そのまま正確な角度θ２，θ３として採用してもよい。
【００６２】
次にアーム撓み補正手段３２は、アーム５を構成する各部の長さを算出する。具体的には、アーム基部１１のアーム長ｌ１と第二アーム可動部１３の先端固定長Ｉ４は既知の固定長であり、予めアーム撓み補正手段３２に記憶されている。また第一アーム可動部１２のアーム長ｌ２と、第二アーム可動部１３のアーム長Ｉ３から先端固定長ｌ４を差し引いた値は、第一アーム可動部１２と第二アーム可動部１３が同じ量だけ出没する関係で等しくなる。したがって、エンコーダ２５により検出されるアーム５の撓み長さＬと、アーム基部１１のアーム長ｌ１と、第二アーム可動部１３の先端固定長Ｉ４とから、アーム撓み補正手段３２は、次の数式を利用して第一アーム可動部１２のアーム長ｌ２と、第二アーム可動部１３のアーム長Ｉ３とをそれぞれ算出する。
【００６３】
【数７】

【００６４】
【数８】

【００６５】
次にアーム撓み補正手段３２は、前記打設中のアーム基部１１の正確な角度θ２と、第二アーム可動部１３の正確な角度θ３から、以下の数式を利用して撓み角θｓを算出する。これは、第一アーム可動部１２の撓み角θｓと、第二アーム可動部１３の撓み角θｓが等しいという条件の下で算出される。
【００６６】
【数９】

【００６７】
数９から第一アーム可動部１２および第二アーム可動部１３の撓み角θｓが求められると、第一アーム可動部１２と第二アーム可動部１３との成す角度θｙは、三角形の内角と外角との関係から、アーム撓み補正手段３２により次の数式にて簡単に求めることができる。
【００６８】
【数１０】

【００６９】
上記角度θｙが算出されると、アーム撓み補正手段３２は、第一アーム可動部１２の基端から第二アーム可動部１３の先端に至る長さｌｘを、既に算出された第一アーム可動部１２のアーム長ｌ２と、第二アーム可動部１３のアーム長Ｉ３から、余弦定理によって次の数式のように算出する。
【００７０】
【数１１】

【００７１】
上記長さｌｘが算出されると、第一アーム可動部１２と長さｌｘとの成す角度θｕの余弦（Ｃｏｓθｕ）は、第一アーム可動部１２の基端から第二アーム可動部１３の先端に至る長さｌｘは、既に算出された第一アーム可動部１２のアーム長ｌ２と、第二アーム可動部１３のアーム長Ｉ３から、余弦定理によって次の数式のように算出できる。
【００７２】
【数１２】

【００７３】
また角度θｕは、Ｃｏｓθｕの逆数を取って数１３のように算出できる。
【００７４】
【数１３】

【００７５】
但し、上記数１３における右辺の１８０／πは、角度θｕの単位をラジアンではなく度（°）として算出するためのものである。続いてアーム撓み補正手段３２は、アーム基部１１と長さｌｘとの成す角度θｚを算出する。これは、三角形の内角と外角との関係から、次の数式にて求めることができる。
【００７６】
【数１４】

【００７７】
角度θｚが求められると、アーム撓み補正手段３２は、第一可動部１２のアーム長ｌ１と、上記数１２で算出した長さｌｘと、上記数１４で算出した角度θｚから、アーム５の真の直線長さＬｔを余弦定理によって、次の数式にて算出する。
【００７８】
【数１５】

【００７９】
また上記数１５により、アーム５の真の直線長さＬｔを算出すると、アーム撓み補正手段３２は、アーム５の真の直線長さＬｔとアーム基部１１との成す角度θｗの余弦（Ｃｏｓθｗ）を、余弦定理によって次の数式のように算出する。
【００８０】
【数１６】

【００８１】
また角度θｗは、Ｃｏｓθｗの逆数を取って数１７のように算出できる。
【００８２】
【数１７】

【００８３】
但し、上記数１７における右辺の１８０／πは、角度θｗの単位をラジアンではなく度（°）として算出するためのものである。これに基づきアーム撓み補正手段３２は、アーム５の真の起伏角度θｔを、次の数式にて算出する。
【００８４】
【数１８】

【００８５】
このようなアーム撓み補正手段３２を備えたことにより、施工開始時や施工中にアーム５が撓んだとしても、エンコーダ２５およびアーム傾斜計２９，３１を設け、場合によっては車両傾斜計３０を付加するだけで、アーム５の枢着部６から先端までの真の直線長さＬｔと、この真の直線長さＬｔと水平面とのなす角度である真の起伏角度θを正しく算出することができる。したがって、この結果を基にして杭深度算出手段４２で正確な杭深度を求めたり、あるいは目標アーム長さ算出手段４１で正確な目標アーム長さＬｎを求めることができるようになる。
【００８６】
なお、アーム５の伸縮段数が実施例以外の場合であっても、上述の余弦定理を利用して真の直線長さＬｔと真の起伏角度θｔを算出する手順は同じである。
【００８７】
以上のように本実施例では、基端にある枢着部６を中心に起伏可能に回動し、且つ伸縮自在なアーム５の先端に取付けられる杭すなわち杭芯１５の鉛直度を管理する杭鉛直度管理装置において、アーム５に沿った枢着部６から先端までの撓み長さＬを検出するアーム長検出手段としてのエンコーダ２５と、アーム５の基端の起伏角度θ２’を検出する第一アーム角度検出手段としてのアーム傾斜計２９と、アーム５の先端の起伏角度θ３’を検出する第二アーム角度検出手段としてのアーム傾斜計３１と、アーム傾斜計２９，３１およびエンコーダ２５からの検出出力に基づき、アーム５の枢着部６から先端までの真の直線長さＬｔを算出すると共に、この直線長さＬｔと水平面との間のなす角度である真の起伏角度θｔを算出するアーム撓み補正手段３２と、杭芯１５が貫入位置Ｐの垂直線上に位置するときの枢着部６から杭芯１５に至る水平面に沿った距離（ロッド距離Ｌ２）と、アーム撓み補正手段３２で算出された真の起伏角度θｔとから、杭芯１５が貫入位置Ｐの垂直線上に位置するときのアーム５の枢着部６から先端までの目標直線長さ（目標アーム長さＬｎ）を算出する制御手段としての演算処理部３５とを備えている。
【００８８】
この場合、杭芯１５を打設する施工作業中は、杭芯１５を軟弱地盤１に押し込む力と杭芯１５が軟弱地盤１から受ける反発力とによって、アーム５自身に撓みが生じ、この撓んだ状態のアーム５の撓み長さＬがエンコーダ２５で検出される。それと共にアーム５が撓むと、アーム傾斜計２９，３１でそれぞれ検出される起伏角度θ２’θ３’間に差異を生じ、この差異とアーム５の撓み長さＬとを利用して、アーム撓み補正手段３２はアーム５の枢着部６から先端までの真の直線長さＬｔと、この直線長さＬｔと水平面との間をなす角度である真の起伏角度θｔを算出する。そして、このようにして得られた真の起伏角度θｔと、予め分っている杭芯１５が貫入位置Ｐの垂直線上に位置するときの枢着部６から杭芯１５に至る水平面に沿ったロッド距離Ｌ２とによって、制御手段である演算処理部３５がアーム５の枢着部６から先端までの目標アーム長さＬｎを算出する。
【００８９】
したがって、アーム撓み補正手段３２が算出する真の直線長さＬｔが、目標直線長さＬｎに一致するように、オペレータがアーム５を出し入れすれば、施工中にアーム５が撓んだ場合でも、杭芯１５の鉛直度を保った状態で貫入位置Ｐに打ち込むことが可能になり、オペレータの技量に左右されることなく、正しく杭作業を行なうことができる。
【００９０】
また本実施例では、アーム５を保持する保持体すなわち建柱車２の傾きを検出する傾斜検出手段としての車両傾斜計３０をさらに備え、アーム撓み補正手段３２は、アーム傾斜計２９，３１からの各検出出力（θ２’，θ３’）から、杭芯１５が地面すなわち軟弱地盤１に押し込まれるときの建柱車２の浮き上がり角度（θ４Δ）を差し引いた値を基に、真の直線長さＬｔや真の起伏角度θｔを算出している。
【００９１】
この場合、杭芯１５が軟弱地盤Ｐに押し込まれるときの建柱車２の浮き上がり角度θ４Δを車両傾斜計３０からの検出出力で得ることができるので、アーム傾斜計２９，３１で検出されるアーム５の基端や先端の各起伏角度θ２’，θ３’から浮き上がり角度θ４Δを差し引いて、真の直線長さＬｔや真の起伏角度θｔを算出することができる。したがって、建柱車２の浮き上がりや縦揺れ角をも考慮したアームの目標直線長さ（目標アーム長さＬｎ）の算出が可能となり、杭芯１５の鉛直度をより正しく保つことができる。
【００９２】
さらにこの場合は、杭芯１５を貫入する直前の開始位置までアーム５を回動して引上げたときに、この杭芯１５が貫入位置Ｐ上で鉛直となるアーム５の開始長さＬ０と開始起伏角度θ０とを算出し、このアーム５の開始長さＬ０および開始起伏角度θ０と、現在のアーム５の直線長さＬ１と、現在のアーム５の起伏角度θとから、余弦定理を利用して杭芯１５の深度Ｈを算出する杭深度算出手段４２を備えてもよい。
【００９３】
こうすることで、杭深度算出手段４２は、杭芯１５を貫入する直前の開始位置におけるアーム５の開始長さＬ０と開始起伏角度θ０とを基にして、現在のアーム５の長さＬ１と起伏角度θから、余弦定理を利用して深度Ｈを算出することができる。したがって、杭深度算出手段４２が算出した深度Ｈにより、オペレータは作業中においてアーム５の目標長さＬｎのみならず、地盤１に貫入した杭芯１５の深さを直接同時に知ることができる。
【００９４】
さらに本実施例における杭深度算出手段４２は、現在のアーム５の長さＬ１が、演算処理部３５で算出したアーム５の目標長さＬｎの許容範囲内にある場合にのみ、杭芯１５の深度Ｈを算出するように構成している。
【００９５】
こうすると杭深度算出手段４２は、現在のアーム５の長さＬ１が、アーム５の目標長さＬｎの許容範囲内にある時にだけ、算出した杭芯１５の深度Ｈを外部に出力する。したがって、杭深度Ｈのデータを管理する側では、杭芯１５が鉛直でない状態の誤ったデータを取り込む虞れがなく、正しい杭深度Ｈのデータ管理を行なうことが可能になる。
【００９６】
本発明は上記実施例に限定されるものではなく、種々の変形実施が可能である。本発明における杭とは、地盤の貫入位置Ｐに貫入する棒状体のことをいうもので、例えば鋼管杭でもよく、さらにその目的は本実施例のような地盤改良にのみ限定されるものではない。
【００９７】
【発明の効果】
本発明の請求項１における杭鉛直度管理装置によれば、施工中にアームが撓んだ場合でも、オペレータの技量に左右されることなく、正しく杭作業を行なうことができる。
【００９８】
本発明の請求項２における杭鉛直度管理装置によれば、保持体の浮き上がりや縦揺れ角をも考慮したアームの目標直線長さの算出を行なうことで、杭の鉛直度をより正しく保つことができる。
【図面の簡単な説明】
【図１】本発明の一実施態様を示す杭鉛直度管理装置の全体構成を表わした概略図である。
【図２】同上要部の機能構成を示すブロック図である。
【図３】同上打設時における杭鉛直度管理装置の全体構成を表わした概略図である。
【図４】同上打設時における杭鉛直度管理装置のアーム５の態様を拡大して表わした概略説明図である。
【図５】同上杭芯の基準姿勢を確定した状態を示す表示器の正面図である。
【図６】同上施工最終姿勢を記憶するときの状態を示す表示器の正面図である。
【図７】同上杭芯を所定の高さまで引上げたときの状態を示す表示器の正面図である。
【図８】同上杭入施工作業の開始時における状態を示す表示器の正面図である。
【図９】同上アームの長さを正しく調節する前の状態を示す表示器の正面図である。
【図１０】同上アームの長さを正しく調節したときの状態を示す表示器の正面図である。
【図１１】同上パラメータ設定画面を表示したときの状態を示す表示器の正面図である。
【図１２】同上杭芯を押し込むまでの動作手順を示すフローチャートである。
【符号の説明】
２ 建柱車（保持体）
５ アーム
６ 枢着部
１５ 杭芯（杭）
２５ エンコーダ（アーム長検出手段）
２９ アーム傾斜計（第一アーム角度検出手段）
３０ 車両傾斜計（傾斜検出手段）
３１ アーム傾斜計（第二アーム角度検出手段）
３２ アーム撓み補正手段
３５ 演算処理部（制御手段）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a pile mounting operation in which a pile is attached to the tip of an arm that is rotatable and expandable and retractable, and in which a pile is vertically extended and managed so that the verticality of the pile is maintained by expanding and contracting the arm. It relates to a degree management device.
[0002]
[Prior art]
In residential ground, for example, a soil survey to estimate soil resistance by measuring the penetration resistance of the soil in situ using a Swedish sounding test machine, etc., and measuring its hardness, softness or tightness, and the composition of the soil layer, in advance Done. When the soil is determined to be soft ground as a result of the ground survey, the cement-based solidifying agent is slurried, and mechanically mixed and stirred while being poured into the target ground to form the ground soil into a columnar shape. Ground improvement work is underway to solidify and strengthen the ground.
[0003]
In this series of construction work, it is necessary not only to align the tip of the pile core with the accurate insertion position of the soft ground, but also to particularly manage the verticality (inclination state) and depth of the pile core during construction. That is, unless the pile core is constantly driven vertically and driven into soft ground, the completed improved ground is constructed in a zigzag state and the ground cannot be satisfactorily strengthened. A similar problem also occurs when the insertion depth of the pile core is insufficient.
[0004]
Furthermore, the control of the verticality and depth of the pile core is not limited to a dedicated pile driving vehicle that drives the pile core vertically with a hammer, etc. It is more difficult to attach a pile core to the tip of an arm that rotates, and push in the pile core with this arm to perform work. In this case, while the pile core is attached to the tip of the arm, the operator sends a signal to the operator of the construction vehicle while visually confirming the target position, and aligns the tip of the pile core with the target position. Next, the operator performs excavation of the pile core vertically and to a predetermined depth while moving the arm in and out and turning the arm, relying on a visual cue of a worker near the target position. However, the degree to which the arm is moved in and out and the arm is rotated are left to the intuition of the operator, and considerable skill is required for the operation.
[0005]
As a method for managing the verticality of a pile core at the time of driving a pile, for example, a method of straightening a pile in driving a pile as disclosed in Patent Document 1 is known. This is achieved by installing an electronic total station at each of the two observation points and collimating and tracking the mark provided on the pile by the electronic total station, so that the front and rear tilting means and the left and right tilting means of the pile driving work device holding the pile are maintained. To maintain the verticality of the pile.
[0006]
[Patent Document 1]
Japanese Patent Publication No. 4-73729 (paragraph number in the specification)
[0006]
[0007]
[Problems to be solved by the invention]
However, in the above method, every time a pile driving operation is performed, an electronic total station must be installed at a position away from the pile, which is troublesome. Moreover, although it is possible to obtain information on how much the pile should be moved in the front-rear direction or the left-right direction, it is not known how much the arm should be extended or retracted at this time based on that information. The quality of the pile operation depends on the skill of the operator who operates the work vehicle.
[0008]
In order to avoid such a problem, the present applicant has previously disclosed in Japanese Patent Application No. 2001-380710 a pile that pivots up and down around a pivot at the base end and is attached to the tip of a telescopic arm. In a pile verticality management device for managing verticality, an arm length detecting means for detecting a length from a pivot portion of the arm to a tip thereof, and an arm angle detecting means for detecting an elevation angle of the arm, and When the tip is made to coincide with the penetrating position of the pile, the arm length and the undulation angle in the final posture of the pile respectively taken from the arm length detecting means and the arm angle detecting means, and the current taken from the arm angle detecting means. And a control means for calculating a target length of an arm in which a pile is located on a vertical line of a penetration position from the undulating angle of the arm.
[0009]
However, the force pushing the pile core during casting and the repulsive force received from the soft ground by the pile core become a force that pushes up the arm, causing the arm itself to bend. Therefore, even if the actual arm length is matched with the target arm length, the pile cannot be driven vertically into the target penetration position.
[0010]
In addition, not only does the arm bend during the placement of the pile core, but the pillar truck as a holding body that holds the arm also lifts and pitches back and forth, causing the arm elevation angle detected by the arm angle detection means to rise and fall. Further errors occur. Therefore, unless the target length of the arm is calculated in consideration of the lifting and pitching angle of the vehicle body, the verticality of the pile core cannot be maintained correctly.
[0011]
The present invention is intended to solve the above problems, and even if an arm flexes during construction, without depending on the skill of the operator, a pile verticality management device capable of performing pile work correctly. Its purpose is to provide.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a pile verticality management device according to claim 1 of the present invention is a pile mounted on a distal end of a telescopic arm, which is pivotally movable up and down around a pivot at a base end. An arm length detecting means for detecting a bending length from a pivot portion along the arm to a tip thereof, and a first arm for detecting an elevation angle of the base end of the arm. An angle detecting means, a second arm angle detecting means for detecting an elevation angle of the arm tip, and the arm based on detection outputs from the arm length detecting means, the first arm angle detecting means and the second arm angle detecting means. Arm deflection correction means for calculating the true straight-line length from the pivot point to the tip of the arm, and calculating the true undulation angle between this straight line and the horizontal plane, and the pile is located on the vertical line of the penetration position. When said A control for calculating a target straight line length from a pivotal connection portion to a tip of the arm located on a vertical line of the penetration position from the distance along a horizontal plane from the attachment portion to the pile and the true undulation angle. Means.
[0013]
In this case, during the driving of the pile, the arm itself is bent by the force pushing the pile into the ground and the repulsive force received from the ground, and the bending length of the bent arm is determined by the arm length detecting means. Is detected by When the arm is bent at the same time, a difference is generated between the undulation angles detected by the first arm angle detecting means and the second arm angle detecting means, and the difference and the bending length of the arm are used to make the arm bending correcting means. Calculates the true linear length from the pivot point of the arm to the tip and the true undulation angle between this straight line and the horizontal plane. The control means determines the true undulation angle obtained in this way, and the distance along the horizontal plane from the pivot point to the pile when the previously known pile is located on the vertical line of the penetration position. Calculate the target linear length from the pivot point of the arm to the tip.
[0014]
Therefore, if the operator moves the arm in and out so that the true straight line length calculated by the arm deflection correcting means matches the target straight line length, even if the arm is bent during construction, the verticality of the pile is reduced. It is possible to drive the pile into the penetrating position while maintaining it, and the pile operation can be performed correctly without being affected by the skill of the operator.
[0015]
The pile verticality management device according to a second aspect of the present invention, in the configuration according to the first aspect, further includes a tilt detection unit that detects a tilt of a holding body that holds the arm, and the arm deflection correction unit includes the tilt correction unit. The true linear length and the true undulation angle are calculated by subtracting the rising angle of the holder when the pile is pushed into the ground from each detection output from the one arm angle detecting means and the second arm angle detecting means. Is what you do.
[0016]
In this case, since the lifting angle of the holder when the pile is pushed into the ground can be obtained by the detection output from the inclination detecting means, the arm detected by the first arm angle detecting means or the second arm angle detecting means can be obtained. The true straight length and the true undulation angle can be calculated by subtracting the rising angle from the undulation angles at the base end and the arm tip. Therefore, it is possible to calculate the target linear length of the arm in consideration of the lifting and the pitch angle of the holding body, and it is possible to more accurately maintain the verticality of the pile.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a pile verticality management device according to the present invention will be described with reference to the accompanying drawings.
[0018]
FIG. 1 is a schematic configuration diagram of the present apparatus. In FIG. 1, reference numeral 1 denotes a soft ground, which is the ground on which improvement work needs to be performed, and reference numeral 2 denotes a pole carriage as a general-purpose construction work machine disposed on the soft ground 1. As is well known in the art, the construction of the pole carriage 2 is a horizontally rotatable holding mechanism 4 attached to an upper portion of the vehicle body 3, and a telescopic arm 5 whose base end is pivotally attached to the holding mechanism 4. The arm 5 is configured to be rotatable about a pivot portion 6 at a base end. Reference numeral 7 denotes a rotatable wheel that comes into contact with the surface of the soft ground 1, and reference numeral 8 denotes a grounding leg that prevents the vehicle body 3 from falling down during work or the like. Here, the pole wheel 2 is provided as a holding body for holding the arm 5, but may be other than a vehicle.
[0019]
The arm 5 has a cylindrical arm base 11 provided with a pivotal connection 6 with the holding mechanism 4 at a base end thereof, a first arm movable part 12 protruding and retracting from a tip of the arm base 11, a first arm movable part. The second arm movable part 13 is protruded and retracted from the tip of the first arm movable part 12 with the emergence of the second arm 12. The arm 5 and thus the tip of the second arm movable part 13 are provided with a tool. A pile mounting portion 16 for mounting a certain pile, that is, a pile core 15 so as to be rotatable in the axial direction is provided. The pile core 15 here is, similarly to the pile core 102 in the conventional example, a digging part 17 for excavating the soft ground 1 at its tip and a cement for injecting a cement-based solidifying agent 19 into the digged hole 18. And an injection unit 20. Although the arm 5 in the embodiment has three stages, it may have two stages or four or more stages, and the number of stages is not particularly limited.
[0020]
Reference numeral 25 denotes a wire-type encoder as arm length detecting means for detecting the length from the pivot portion 6 to the tip of the arm 5 as an arm length L. The encoder 25 is composed of a wire 26 having one end attached to the distal end of the arm movable section 12 and an encoder body 27 that winds and stores the wire 26 around a rotating body (not shown). The arm length L is measured by converting the winding length of the wire 26 accompanying the above from the rotation speed of the rotating body in the encoder main body 27. In particular, the encoder 25 of the present embodiment uses a ring-shaped holder 28 through which the wire 26 passes so that the length along the arm 5 (bending length) can be detected even when the arm 5 is bent. 11 and the first arm movable portion 12 are attached to respective distal ends. The arm length detecting means is not limited to a wire type encoder.
[0021]
Reference numeral 29 denotes an arm inclinometer as first arm angle detection means for detecting the angle of elevation of the arm base 11 at the base end of the arm 5, that is, the angle θ2 ', which is the angle of inclination with respect to the horizontal plane. Reference numeral 31 denotes another arm inclinometer for detecting the undulation angle θ3 ′ of the second arm movable portion 13 at the tip of the arm 5. In addition to the arm inclinometers 29 and 31, a vehicle inclinometer 30 for detecting the inclination (body angle) of the pole carriage 2 during construction is provided. The vehicle inclinometer 30 is for calculating the lift angle θ4Δ of the pole carriage 2 when the pile core 15 is pushed into the ground. Specifically, for example, an analog output type inclinometer or the like is used. By combining a high-sensitivity magnetic sensor and a pendulum with a magnet attached to the tip, a voltage corresponding to the angle of the pendulum is output in the X and Y directions. The arm inclinometer 29 is mounted near the base end of the arm 5, and the vehicle inclinometer 30 is mounted on the holding mechanism 4. However, the vehicle inclinometer 30 may be directly mounted on the vehicle main body 3 other than the holding mechanism 4.
[0022]
FIG. 2 is a block diagram showing a functional configuration of the device. In the figure, reference numeral 35 denotes a bending length L of the arm 5 obtained from the encoder 25, an angle θ2 'of the arm base 11 obtained from the arm inclinometer 29, and a second arm obtained from the arm inclinometer 31. In addition to the undulation angle θ3 ′ of the movable part 13, the angle difference between the time when the construction vehicle starts to be cast and the time during the placement obtained from the vehicle inclinometer 30 is calculated and taken in as a rising angle θ4Δ, and the arm 5 is bent. The true straight length Lt and the true undulation angle θt of the arm 5 assumed to be not deviated are calculated so that the pile core 15 attached to the tip of the arm 5 penetrates the target penetration position P in a vertical state. The arithmetic processing unit calculates the linear length (target arm linear length) Ln of the target arm 5 and outputs the calculation result to the display 36 as output means. The arithmetic processing unit 35 is configured by control means such as a microcomputer. Reference numeral 37 denotes an operation unit such as a touch panel operated by an operator, which can switch the display contents of the display 36 and set various parameters in accordance with an instruction from the operation unit.
[0023]
More specifically, the arithmetic processing unit 35 sets the tip of the arm 5 to the penetration position P on the surface of the soft ground 1 in a state where the pile core 15 which is a rod is not attached to the arm 5 first (see FIG. 1). And the arm length from the pivot 6 to the tip of the arm 5 obtained by the encoder 25 with respect to the horizontal angle obtained by the vehicle inclinometer 30 in the reference posture. L0 and the reference attitude storage means 38 for taking in and storing the angle θ2 ′ of the arm base 11 with respect to the horizontal plane obtained by the arm inclinometer 29, and the arm 5 with the pile core 15 not mounted on the arm 5. Based on the arm length Lx and the angle θx when the tip is matched with the penetration position P, assuming that the pile core 15 is attached to the tip of the arm 5 in a vertical state, the pile 6 extends from the pivoting portion 6 along the horizontal plane. The distance to the core 15 is the rod distance And a Kuishin distance calculating unit 39 that calculates a 2.
[0024]
After storing each data in the reference posture, the arithmetic processing unit 35 attaches the pile core 15 to the tip of the arm 5, and sets the lower end of the pile core 15 to press the penetration position P of the soft ground 1. When the arm 5 is moved to the start position immediately before the piling operation, the true straight length Lt and the true linear length Lt of the arm 5 calculated by the arm deflection correcting means 32 described later are assumed to be not bent. The undulation angle θt is stored as the start length Lo and the start angle θ0, respectively, and the rod distance L2 newly calculated from these values is stored, and the construction start arm position storage means 40 for outputting to the display 36 is provided. It has.
[0025]
In addition, the arithmetic processing unit 35 determines the distance between the pivotal connection 6 and the distal end of the arm 5 based on the detection outputs from the arm inclinometers 29 and 31 that detect the angles θ2 and θ3 of the base and distal ends of the arm 5. An arm deflection correcting means 32 is provided for calculating a true straight line length Lt and calculating a true undulation angle θt which is an angle formed between the straight line and a horizontal plane. In particular, the arm deflection correcting means 32 in this embodiment is designed to be used when the pile core 15 is pushed into the soft ground 1 based on the difference between the vehicle body angles detected by the vehicle inclinometer 30 at the start of construction and during construction. 2 is calculated from the detected outputs from the arm inclinometers 29 and 31, to calculate the true linear length Lt and the true undulation angle θt. The calculation is performed with high accuracy. Further, as described above, the arm deflection correction means 32 calculates the true linear length Lt and the true undulation angle θt of the arm 5 when the arm 5 is at the start position of the pile insertion work, respectively, as the start length. It is calculated as Lo and the start angle θ0.
[0026]
Further, the arithmetic processing unit 35 sets the pile core 15 on the vertical line of the penetration position P from the true undulation angle θt obtained by the arm deflection correcting means 32 and the rod distance L2 calculated in advance by the starting arm position storing means 40. Calculate a target linear length (target arm length) Ln from the pivot portion 6 to the tip of the arm 5 at the time of positioning, and match it with the true linear length Lt obtained by the arm deflection correcting means 32. The target arm length calculating means 41 which outputs the current arm length L1 to the display 36 together with the current arm length L1, and the target arm length Ln obtained by the target arm length calculating means 41 by the operator operating the expansion and contraction of the arm 5. When the current true linear length Lt reaches within the allowable range, the start length L0 of the arm 5, the current linear length (arm length) L1 of the arm 5, and the arm base 11 at the start of construction. Angle of Using the cosine theorem, the penetration depth of the pile core 15 from each of the operation angles θ1 obtained from the difference between the start angle) θ0 and the current true undulation angle θ of the arm 5 obtained by the arm deflection correction means 32. In other words, each of the pile depth calculating means 42 for calculating the depth H and outputting this to the display 36 is provided.
[0027]
Further, reference numeral 43 denotes a parameter setting change unit which has a function of setting or changing a sampling time and a sampling interval for collecting various data at the time of construction, and an allowable range of the target arm length Ln, for example. Then, the start length L0 of the arm 5 at the start of construction, the start angle θ0 of the arm 5 at that time, the rod distance L2 obtained by the pile center distance calculation means 39 and the start arm position storage means 40, , And the corrected current arm length L1 at the time of calculating the depth, and the like, are sent to a center (not shown) at any time via data transmission means 44 such as a mobile phone.
[0028]
Next, the display configuration and the operation of the present apparatus will be described together with reference to the front views of the display 36 shown in FIGS. FIG. 5 shows a main display form of the display 36 during the work, wherein 45 is a work number display section, and 46 is a pile number display section. The work number displayed on the work number display section 45 is assigned in advance to the center in association with the address and the subject in order to specify the address and the subject of the work. Are assigned so that the dated 13-digit numbers do not overlap. The process number is input on a process number input screen different from the main display, temporarily stored in a memory card (not shown), and can be called up at the start of work and displayed on the process number display section 45. At this time, the number displayed on the pile number display section 46 starts from “001”, and is automatically incremented by +1 each time one pile operation is completed.
[0029]
Numeral 47 denotes a digital display unit for digitally displaying the measured values of each part during construction, which is a column, ie, a depth display unit 48 for indicating the depth H of the pile core 15, and an integrated rotation speed display for indicating the integrated rotation speed of the pile core 15. Section 49, an integrated flow rate display section 50 indicating the integrated flow rate of cement milk as the solidifying agent 19, a current arm angle display section 51 indicating the current angle θ of the arm 5 calculated by the arm deflection correcting means 32, A target arm length display section 52 representing the target arm length Ln at the time and a current arm length display section 53 representing the current arm 5 length L1 calculated by the arm deflection correcting means 32. On each of these display sections 48 to 53, the current measured value is displayed as a number. Numeral 54 is a meter display unit which also uses an analog display, which is an instantaneous flow rate display unit 55 which digitally and analogly displays the instantaneous flow rate of cement milk, and a press-in pressure display unit which displays the press-in pressure of the pile core 15 in a digital and analog manner. 56, a moving speed display unit 57 for displaying the moving speed of the pile core 15, and a rotational speed display unit 58 for displaying the rotational speed of the pile core 15. At the lower right of these instantaneous flow rate display section 55, press-fit pressure display section 56 and speed display section 57, the maximum scale value of the meter is displayed by a numeral, but this value can be arbitrarily changed.
[0030]
Further, the display screen of the display unit 36 includes, as an operation unit 37 using a touch panel, a start button 60 as a start instruction unit, a stop button 61 as a stop instruction unit, a construction button 62 as a restart instruction unit, and a temporary operation button. A joint pile button 63 serving as a stop instruction means is provided. The start button 60 is operated when starting the measurement of each part. When the start of measurement is instructed, the pile number displayed on the pile number display section 46 is incremented by +1 and the process number displayed on the factory number display section 45 is added. In the turn, the operation information of each section regarding the pile number displayed on the pile number display section 46 is taken into the arithmetic processing section 35 and displayed on the display 36. In addition, when the pillar-car 2 itself has not started the operation, the operation of the start button 60 is invalidated to prevent unnecessary operation information from being taken in. On the other hand, the stop button 61 is operated when ending the measurement of each unit, and when the measurement end is instructed, the acquisition of the operation information of each unit to the arithmetic processing unit 35 stops. Further, the joint pile button 63 is operated when a joint pile or a trouble occurs. When this button is pressed, the measurement of each part is temporarily stopped. Further, the construction button 62 is operated when the construction is resumed, and when this button is pressed, the measurement of each part is restarted.
[0031]
In addition, in the lower part of the display screen of the display 36, as a screen switching operation means of the display unit 37, a production number input screen switching button 64, a data transmission screen switching button 65, a graph screen switching button 66, a pump screen switching button A button 67, a vertical construction support switching button 68, and a parameter screen switching button 69 are provided. By operating any one of the buttons 64 to 69, a screen different from the main display shown in FIG. 5 is displayed. It is displayed on the display 36. Reference numeral 70 denotes a pump operation status display unit for displaying the operation status of an automatically operated pump (not shown) for injecting cement milk. Hereinafter, only the vertical construction support operation related to the present invention and the corresponding parameter setting will be described.
[0032]
The flowchart in FIG. 12 shows the construction procedure after pressing the vertical construction support switching button 68 in FIG. In FIG. 12, in the first step S <b> 1, in a state in which the pile core 15 is not attached to the arm 5 of the pole carriage 2, the tip of the arm 5 matches the preset penetration position P on the surface of the soft substrate 1. Then, the length and angle of the arm 5 are adjusted by the operation of the operator, and the reference posture of the pile core 15 is determined.
[0033]
FIG. 6 shows a display form of the display 36 at this time. Reference numeral 71 denotes an arm display unit for schematically displaying the current state of the arm 5 and the like. Reference numeral 72 denotes a start angle θ0, an operation angle θ1, and a start length of the arm 5 described above corresponding to the arm display unit 71. This is a data numeral display section for displaying L0, the current arm length L1, and the rod distance L2 by numerals. Reference numeral 73 denotes a pile core detection button that forms a part of the operation unit 37. Each time the pile core detection button 73 is pressed, the display color of a portion corresponding to the pressed position is switched. In addition, a current arm angle display section 51, a target arm length display section 52, and a current arm length display section 53 which are also displayed on the main display screen of FIG. 5 are provided, and a depth display for displaying the depth of the pile core 15 is provided. A part 74 is provided.
[0034]
During the operation of the arm 5, the current true undulation angle θ of the arm 5 obtained by the arm deflection correcting means 32 at the present time is displayed on the current arm angle display section 51 at every fixed sampling time, and the arm The current arm length L1 obtained by the deflection correcting means 32 is displayed on the current arm length display section 53 and the data numeral display section 72.
[0035]
The display screen of the display 36 includes an operation unit 37 using a touch panel, an arm angle operation button 75 for moving the arm 5 up and down or automatically moving the arm 5 to a predetermined angle, and expanding and contracting the arm 5. There are provided an arm extension / contraction operation button 76, a stake-down button 77, a parameter screen switching button 78 for displaying a parameter setting screen described later, and a return button 79 for returning to the main screen of FIG. As described above, the raising / lowering operation and the expansion / contraction operation of the arm 5 can be performed not only by the lever (not shown) provided on the pole wheel 2, but also by the operation unit 37 provided on the display 36.
[0036]
Returning to the description of FIG. 12 again, when the reference posture is determined by aligning the tip of the arm 5 with the penetration position P in step S1, the pile core detection button 73 is pressed in the next step S2. Then, the process shifts to step S3, where the reference attitude storage means 38 constituting the arithmetic processing section 35 sets the arm length Lx and the angle θx when the tip of the arm 5 coincides with the penetration position P with the arm deflection correcting means 32. , And these values are taken in, and these values are stored as reference postures. At the same time, the pile center distance calculating means 39 calculates the rod distance L2 from the pivoting portion 6 along the horizontal plane to the pile center 15 when the pile center 15 is vertically attached to the tip of the arm 5 (the arm display in FIG. 6). Is calculated from the arm length Lx and the angle θx by the following formula.
[0037]
(Equation 1)

[0038]
The rod distance L2 is output from the pile center distance calculating means 39 to the display 36 and is always displayed on the data numeral display section 72.
[0039]
After the reference attitude of the pile core 15 is stored and the rod distance L2 is calculated, the pile core 15 is attached to the tip of the arm 5 and the arm angle operation button 75 is pressed to raise the arm 5 to an arbitrary height (step S5). ). FIG. 7 shows a display form of the display 36 at this time. When the hand touches the pile core detection button 73 in step S2, the display color located at the pile core detection button 73 changes. Thereby, the operator can directly visually confirm that the reference posture of the pile core 15 has already been stored. Also, if the length of the pile core 15 is known, and the length is input from the operation unit 37, the arithmetic processing unit 35 automatically sets the pulling angle until the tip of the arm 5 is pulled up to the length of the pile core 15. Can be calculated. Therefore, if the calculation unit 35 as a control means is configured so that the arm 5 is automatically pulled up to this pulling angle when the "automatic" button constituting the arm angle operation button 75 is pressed, the skill of the operator can be improved. The arm 5 can be easily pulled up to the work start position regardless of the degree.
[0040]
When the arm 5 is pulled up, the target arm length calculation means 41 calculates the target length Ln of the arm 5 where the tip of the arm 5 is located on the vertical line of the penetration position P, and this is calculated by the target arm length display section 52 of the display 36. Will be displayed. The target arm length Ln is calculated by the following equation based on the current angle θ of the arm 5 calculated by the arm deflection correcting means 32 and the rod distance L2.
[0041]
(Equation 2)

[0042]
The operator rotates the arm 5 around the pivot 6 and pulls it up, and the current length L1 of the arm 5 displayed on the current arm length display section 52 is within the allowable range of the target arm length Ln. The arm 5 is operated to operate the arm expansion / contraction operation button 76 to extend / contract (step S5). Then, when the current arm length L1 matches the target arm length Ln, the pile core 15 whose lower end has been adjusted to the penetration position P is in a vertical state, and the tip of the arm 5 is on the vertical trajectory of the pile core 15. To position. At this time, the depth display section 74 displays the current arm length L1 calculated by the arm deflection correction means 32 and the pull-up length of the arm 5 calculated by the arithmetic processing section 35 based on the arm angle θ. Is displayed.
[0043]
After the arm 5 is pulled up in this way, when it is confirmed that the arm 5 is vertical with the tip of the arm 5 pressing the penetration position P, the process proceeds to step S6 to instruct the start of construction. Touch the pile core detection button 73 which is also the construction start button again. Accordingly, the arithmetic processing unit 35 determines that the arm 5 is at the start position of the pile-in work, and sets the start angle θ0 and the start length L0 of the arm 5 obtained by the arm bending correction means 32 at that time. While being stored in the start arm position storage means 40, based on the start angle θ0 and the start length L0, the pile center distance calculation means 39 calculates the rod distance L2 again by the following formula.
[0044]
[Equation 3]

[0045]
The rod distance L2 is stored in the construction start arm position storage means 40 (Step S7) and remains unchanged until the construction work is completed. Then, the target arm length Ln is calculated by substituting the start angle θ0 of the arm 5 into the angle θ in Equation 2, and this is displayed on the target arm length display section 52.
[0046]
At the start of the construction, a force for pressing the tip of the pile core 15 against the soft ground 1 is applied from the arm 5 in order to make the tip of the pile core 15 coincide with the penetration position P. For this reason, the arm 5 is flexed by a slight repulsive force, though not so much as when the pile core 15 described later penetrates. Therefore, in order to correctly calculate the target arm length Ln, the arm deflection correction means 32 is used to calculate the start angle θ0 and the start length L0 of the arm 5 when it is assumed that the arm 5 is not bent. I have.
[0047]
FIG. 8 shows a display form of the display 36 at the start of the pile entry work. Here, the corrected angle θ of the current arm 5 (start angle θ0 at the start of construction) is displayed on the arm angle display section 51, and the arm 5 is directed to the angle θ on the target arm length display section 52. The target arm length Ln at that time is displayed, the current arm length L1 (starting length L0 at the start of construction) is displayed on the arm length display section 53, and the depth of the tip of the pile core 15 is displayed on the depth display section 74. H is displayed. The depth H uses the cosine theorem based on the current arm length L1 from the start length L0 of the arm 5 and the operating angle θ1 obtained by subtracting the current angle θ of the arm 5 from the start angle θ0 of the arm 5. It is calculated from the following equation.
[0048]
(Equation 4)

[0049]
According to the above formula, at the start of the work in which the lower end of the pile core 15 does not penetrate the soft ground 1, the current arm length L 1 and angle θ corrected by the arm length / arm up / down angle correction calculating means 32 are equal to the arm 5. The start length L0 matches the start angle θ0, and the depth H calculated by the above equation also becomes 0. The data numeral display section 72 of the display 36 displays the start angle θ0 of the arm 5 at the start of the work, the current operation angle θ1 of the arm 5, the start length L0 of the arm 5, and the current arm length. The length L1 and the rod distance L2 are displayed.
[0050]
Thereafter, normal ground improvement work will be performed. In particular, when the soft ground 1 is excavated by the pile core 15, the depth H and the verticality of the pile core 15 during construction are calculated based on the data stored in the construction start arm position storage means 40. More specifically, when the excavation by the pile core 15 advances and the operation of lowering the angle of the arm 5 is performed by, for example, the arm angle operation button 75, the target arm length calculation means 41 obtains the current arm length correction means 32 obtained from the arm deflection correction means 32. From the angle θ of the arm 5 and the rod distance L2 calculated at the start of construction, a target arm length for keeping the pile core 15 vertical, that is, a target arm length Ln, is calculated and displayed on the target arm length display section 52. Let it. At this time, as shown in FIG. 9, if the current arm length L1 is out of the allowable range (for example, ± 0.10 m) of the target arm length Ln, the corrected current arm length L1 Is displayed, the display color of the current arm length display section 53 changes, and is inverted to, for example, red. The operator sees this, adjusts the length of the arm 5 so that the pile core 15 is vertically penetrated, and matches the corrected current arm length L1 with the target arm length Ln (step). S8). At this time, the depth H calculated by the pile depth calculation means 42 is not correctly displayed on the depth display unit 74 because the corrected current arm length L1 is shifted from the target arm length Ln.
[0051]
FIG. 10 shows a display state of the display 36 when the length of the arm 5 is correctly adjusted. In this case, the current arm length L1 displayed on the current arm length display unit 53 matches the display target arm length Ln displayed on the target arm length display unit 52, and the pile core 15 is Penetrates vertically. Further, the depth H of the pile core 15 displayed on the depth display section 74 also has a correct value. The data transmission means 44 of the arithmetic processing unit 35 sends the correct depth H of the pile core 15 when the current arm length L1 is within the allowable range of the target arm length Ln to the center together with other data. Data collection at an erroneous depth H when the pile core 15 is not vertical can be prevented beforehand. If the length adjustment of the arm 5 is repeated, the pile core 15 can always penetrate into the penetrating position P in a substantially vertical state, and data collection at the correct depth H can be performed.
[0052]
Next, a parameter setting screen displayed on the display 36 when the parameter screen switching button 78 is pressed will be described with reference to FIG. Here, there are provided a parameter value display section 81 for displaying various setting values such as display items such as a sampling section, a sampling timer, an arm allowable range, and a current time setting display section 82 for changing the current time setting. A vertical construction support switching button 83 for displaying the vertical construction support screen shown in FIGS. 6 to 10 described above, a parameter screen switching button 84 for displaying a parameter setting screen different from FIG. A button 85 for returning to the main display screen 5 is also provided as the touch panel operation unit 37 on the display 36.
[0053]
Among them, the sampling section displayed on the parameter value display section 81 sets the collection timing of each piece of construction data collected by the arithmetic processing section 35, and this value is changed to an arbitrary value (for example, a value divisible by 1 m). it can. Further, the sampling timer is to collect data preferentially when the state where the depth H does not change continues for a set time (in this case, 15 seconds) even if the depth H does not change in the sampling section. By operating the enable button 86, this function can be disabled. Further, the arm allowable range is to set an allowable range of the target arm length Ln calculated for keeping the above-mentioned pile core 15 vertical, and by setting this value, data collection of an erroneous depth H is performed. Can be prevented beforehand.
[0054]
As another modified example, each step from step S1 to step S5 shown in FIG. 12 may be omitted, and the work may be performed from the state where the pile core 15 after step S6 is set at the construction start position. This is indicated by the dotted line in FIG.
[0055]
Next, the operation of the arm deflection correcting means 32 in the above series of procedures will be described in detail. As shown in FIG. 3, during the construction work in which the pile core 15 penetrates into the soft ground 1, the force that pushes the pile core 15 into the soft ground 1 and the repulsive force that the pile core 15 receives from the soft ground 1 are caused by the arm 5. In addition, it acts as a force to push up the pole wheel 2, the arm 5 bends itself, and the front of the pole wheel 2 also rises. FIG. 4 is an explanatory view showing the state of the arm 5 in which the bending has occurred. In the arm 5 as in the present embodiment, the tip of the arm base 11 where the first arm movable part 12 is protruded and retracted, and the second arm movable part 12 The distal ends of the first arm movable portions 12 where appear and bend are each bent in a bent state. In the figure, 11 is the arm length of the arm base 11, 12 is the arm length of the first arm movable section 12, 13 is the arm length of the second arm movable section 13, and these are all linear lengths. Reference numeral 14 denotes a fixed length of the distal end of the second arm movable portion 13 necessary for attaching the base end of the pile core 15. This portion is the first arm even if the second arm movable portion 13 is most contracted. It protrudes outward from the tip of the movable part 12.
[0056]
Lt is a true linear length which is a linear length from the pivot portion 6 of the arm 5 to the tip of the arm 5, and θt is a true undulation which is an angle between the true linear length Lt and a horizontal plane. Angle. θ2 is the angle formed between the arm base 11 and the horizontal plane, θ3 is the angle formed between the second arm movable section 13 and the horizontal plane, and lx is the tip of the second arm movable section 13 from the base end of the first arm movable section 12. Length. θu is the angle between the first arm movable part 12 and the length lx, θw is the angle between the true linear length Lt and the arm base 11, and θs is the angle of the first arm movable part 12 with respect to the arm base 11. In this case, the bending angle of the second arm movable part 13 with respect to the first arm movable part 12 is such that the first arm movable part 12 and the second arm movable part 13 appear and disappear by the same amount. Outside angle) is also assumed to be the same θs. Further, θy is an angle (inner angle) formed between the first arm movable portion 12 and the second arm movable portion 13, and θz is an angle (inner angle) formed between the arm base portion 11 and the length lx.
[0057]
In the above configuration, the arm deflection correcting means 32 calculates the true linear length Lt of the arm 5 and the true undulation angle θt of the arm 5. For that purpose, first, during the driving, the angle θ2 ′ of the arm base 11 with respect to the horizontal plane obtained from the arm inclinometer 29 including the influence of the lifting of the vehicle body 3 and the second arm movable obtained from the arm inclinometer 31 The angle .theta.3 'of the portion 13 with respect to the horizontal plane is taken in, and the vehicle body inclination angle of the vehicle body 3 from the vehicle inclinometer 30 stored in advance at the time of starting driving and the vehicle output from the vehicle inclinometer 30 during driving. The difference between the body 3 and the vehicle body inclination angle is calculated as an angle difference θ4Δ.
[0058]
Then, the accurate angle θ2 of the arm base 11 during the driving and the accurate angle θ3 of the second arm movable portion 13 excluding the influence of the lifting of the vehicle body 3 are calculated by an arm inclinometer as shown in the following equation. The angle difference θ4Δ is calculated by subtracting the angle difference θ4Δ from each of the angle θ2 ′ obtained at 29 and the angle θ3 ′ obtained at the arm inclinometer 31.
[0059]
(Equation 5)

[0060]
(Equation 6)

[0061]
When calculating the start length Lo and the start angle θ0 of the arm 5, the vehicle body 3 is not so raised. Further, when the vehicle body 3 does not rise so much during construction, the angle θ2 ′ obtained by the arm inclinometer 29 and the angle θ3 ′ obtained by the arm inclinometer 31 are directly used as accurate angles θ2 and θ3. You may.
[0062]
Next, the arm deflection correcting means 32 calculates the length of each part constituting the arm 5. Specifically, the arm length 11 of the arm base 11 and the fixed length I4 of the distal end of the second arm movable portion 13 are known fixed lengths, and are stored in the arm deflection correcting means 32 in advance. The value obtained by subtracting the fixed length of the tip 14 from the arm length I2 of the first arm movable part 12 and the arm length I3 of the second arm movable part 13 is the same as that of the first arm movable part 12 and the second arm movable part 13. Only in the relationship that appears and disappears. Therefore, based on the bending length L of the arm 5 detected by the encoder 25, the arm length 11 of the arm base 11, and the fixed end length I4 of the second arm movable section 13, the arm bending correcting means 32 calculates Is used to calculate the arm length l2 of the first arm movable section 12 and the arm length I3 of the second arm movable section 13, respectively.
[0063]
(Equation 7)

[0064]
(Equation 8)

[0065]
Next, the arm deflection correcting means 32 calculates the deflection angle θs from the accurate angle θ2 of the arm base 11 during the driving and the accurate angle θ3 of the second arm movable part 13 using the following formula. . This is calculated under the condition that the deflection angle θs of the first arm movable section 12 and the deflection angle θs of the second arm movable section 13 are equal.
[0066]
(Equation 9)

[0067]
When the deflection angles θs of the first arm movable portion 12 and the second arm movable portion 13 are obtained from Expression 9, the angle θy formed by the first arm movable portion 12 and the second arm movable portion 13 is defined by the inner angle and the outer angle of the triangle. From the relationship, the arm deflection correction means 32 can easily obtain the following equation.
[0068]
(Equation 10)

[0069]
When the angle θy is calculated, the arm deflection correcting means 32 calculates the length lx from the base end of the first arm movable section 12 to the distal end of the second arm movable section 13 by using the calculated first arm movable section. From the 12 arm lengths l2 and the arm length I3 of the second arm movable section 13, the following equation is calculated by the cosine theorem.
[0070]
[Equation 11]

[0071]
When the length lx is calculated, the cosine (Cosθu) of the angle θu formed by the first arm movable part 12 and the length lx is calculated from the base end of the first arm movable part 12 to the tip of the second arm movable part 13. Can be calculated from the already calculated arm length l2 of the first arm movable portion 12 and the arm length I3 of the second arm movable portion 13 by the cosine theorem as follows.
[0072]
(Equation 12)

[0073]
Further, the angle θu can be calculated as in Expression 13 by taking the reciprocal of Cos θu.
[0074]
(Equation 13)

[0075]
However, 180 / π on the right side in Equation 13 is used to calculate the unit of the angle θu as degrees (°) instead of radians. Subsequently, the arm deflection correcting means 32 calculates an angle θz formed between the arm base 11 and the length lx. This can be obtained from the relationship between the inner angle and the outer angle of the triangle by the following formula.
[0076]
[Equation 14]

[0077]
When the angle θz is obtained, the arm deflection correcting means 32 determines the trueness of the arm 5 from the arm length l1 of the first movable portion 12, the length lx calculated by the equation (12), and the angle θz calculated by the equation (14). Is calculated by the following equation using the cosine theorem.
[0078]
[Equation 15]

[0079]
When the true linear length Lt of the arm 5 is calculated according to the above equation 15, the arm deflection correcting means 32 calculates the cosine (Cos θw) of the angle θw between the true linear length Lt of the arm 5 and the arm base 11. , Is calculated by the cosine theorem as in the following equation.
[0080]
(Equation 16)

[0081]
Further, the angle θw can be calculated as in Expression 17 by taking the reciprocal of Cos θw.
[0082]
[Equation 17]

[0083]
However, 180 / π on the right side in Equation 17 is for calculating the unit of the angle θw as degrees (°) instead of radians. Based on this, the arm deflection correcting means 32 calculates the true undulation angle θt of the arm 5 by the following equation.
[0084]
(Equation 18)

[0085]
By providing such an arm deflection correcting means 32, even if the arm 5 bends at the start of construction or during construction, the encoder 25 and the arm inclinometers 29 and 31 are provided. By simply adding, it is possible to correctly calculate the true linear length Lt from the pivot portion 6 to the tip of the arm 5 and the true undulation angle θ which is an angle between the true linear length Lt and the horizontal plane. it can. Therefore, based on this result, an accurate pile depth can be obtained by the pile depth calculation means 42, or an accurate target arm length Ln can be obtained by the target arm length calculation means 41.
[0086]
Even when the number of expansion and contraction steps of the arm 5 is other than the embodiment, the procedure for calculating the true linear length Lt and the true undulation angle θt using the above-described cosine theorem is the same.
[0087]
As described above, in the present embodiment, the pile that pivots so as to be able to undulate around the pivotal attachment portion 6 at the base end and that is attached to the distal end of the telescopic arm 5, that is, the pile that manages the verticality of the pile core 15. In the verticality management device, an encoder 25 as an arm length detecting means for detecting a bending length L from the pivot portion 6 along the arm 5 to the distal end, and a undulation angle θ2 'of the base end of the arm 5 An arm inclinometer 29 as one arm angle detecting means, an arm inclinometer 31 as a second arm angle detecting means for detecting the undulation angle θ3 'of the tip of the arm 5, and an arm inclinometer 29, 31 and encoder 25 Based on the detection output, a true straight length Lt from the pivotal portion 6 of the arm 5 to the tip is calculated, and a true undulation angle θt, which is an angle formed between the straight length Lt and a horizontal plane, is calculated. Arm deflection supplement The means 32, the distance (rod distance L2) along the horizontal plane from the pivot portion 6 to the pile core 15 when the pile core 15 is located on the vertical line of the penetration position P, and the arm deflection correction means 32 have calculated the distance. Control means for calculating a target linear length (a target arm length Ln) from the pivot portion 6 to the tip of the arm 5 when the pile core 15 is located on a vertical line of the penetration position P from the true undulation angle θt. And an arithmetic processing unit 35 as
[0088]
In this case, during the construction work for driving the pile core 15, the arm 5 itself bends due to the force of pushing the pile core 15 into the soft ground 1 and the repulsive force received by the pile core 15 from the soft ground 1. The bent length L of the arm 5 in the deflected state is detected by the encoder 25. At the same time, when the arm 5 bends, a difference is generated between the undulation angles θ2 ′ and θ3 ′ detected by the arm inclinometers 29 and 31, and the difference and the bending length L of the arm 5 are used to correct the arm bending. The means 32 calculates a true linear length Lt from the pivot portion 6 to the tip of the arm 5 and a true undulation angle θt which is an angle between the linear length Lt and a horizontal plane. Then, the true undulation angle θt obtained in this manner and the horizontal plane extending from the pivoting portion 6 to the pile core 15 when the pile core 15 previously known is located on the vertical line of the penetration position P are shown. Based on the rod distance L2, the arithmetic processing unit 35, which is a control means, calculates a target arm length Ln from the pivot portion 6 of the arm 5 to the tip.
[0089]
Therefore, if the operator moves the arm 5 in and out so that the true straight length Lt calculated by the arm deflection correcting means 32 matches the target straight length Ln, even if the arm 5 is bent during construction, The pile core 15 can be driven into the penetrating position P while maintaining the verticality of the pile core 15, so that the pile operation can be performed correctly without being affected by the skill of the operator.
[0090]
Further, in the present embodiment, a vehicle inclinometer 30 is further provided as a holder for holding the arm 5, that is, a vehicle inclinometer 30 as an incline detecting means for detecting the inclination of the pole carriage 2. From the detected outputs (θ2 ′, θ3 ′) obtained by subtracting the floating angle (θ4Δ) of the pole-car 2 when the pile core 15 is pushed into the ground, that is, the soft ground 1, based on the true linear length. Lt and the true undulation angle θt are calculated.
[0091]
In this case, the lift angle θ4Δ of the pole carriage 2 when the pile core 15 is pushed into the soft ground P can be obtained by the detection output from the vehicle inclinometer 30, so that the arms detected by the arm inclinometers 29 and 31 can be obtained. The true straight length Lt and the true undulation angle θt can be calculated by subtracting the lift angle θ4Δ from the undulation angles θ2 ′ and θ3 ′ at the base end and the tip end of No. 5. Therefore, it is possible to calculate the target straight line length of the arm (target arm length Ln) in consideration of the rising and pitching angle of the pole carriage 2, and the verticality of the pile core 15 can be maintained more correctly.
[0092]
Further, in this case, when the arm 5 is turned up to the start position immediately before penetrating the pile core 15 and pulled up, the pile core 15 becomes vertical at the penetrating position P and the start length L0 of the arm 5 starts. The undulation angle θ0 is calculated, and the cosine theorem is used based on the start length L0 and the start undulation angle θ0 of the arm 5, the current linear length L1 of the arm 5, and the current undulation angle θ of the arm 5. And a pile depth calculating means 42 for calculating the depth H of the pile core 15 by using the same.
[0093]
In this way, the pile depth calculation means 42 calculates the current length L1 of the arm 5 based on the start length L0 and the start undulation angle θ0 of the arm 5 at the start position immediately before penetrating the pile core 15. The depth H can be calculated from the undulation angle θ using the cosine theorem. Therefore, the operator can directly and simultaneously know not only the target length Ln of the arm 5 but also the depth of the pile core 15 penetrating into the ground 1 during the work, based on the depth H calculated by the pile depth calculation means 42.
[0094]
Furthermore, the pile depth calculation means 42 in the present embodiment only determines whether the current length L1 of the arm 5 is within the permissible range of the target length Ln of the arm 5 calculated by the arithmetic processing unit 35. It is configured to calculate the depth H.
[0095]
Then, the pile depth calculating means 42 outputs the calculated depth H of the pile core 15 to the outside only when the current length L1 of the arm 5 is within the allowable range of the target length Ln of the arm 5. Therefore, on the side managing the data of the pile depth H, there is no possibility that the pile core 15 takes in erroneous data when the pile core 15 is not vertical, and the data management of the correct pile depth H can be performed.
[0096]
The present invention is not limited to the above embodiments, and various modifications can be made. The pile in the present invention refers to a rod-like body penetrating into the ground penetration position P, and may be, for example, a steel pipe pile, and the purpose is not limited to the ground improvement as in the present embodiment. .
[0097]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the pile verticality management apparatus of Claim 1 of this invention, even if an arm bends during construction, pile operation can be performed correctly without being influenced by the skill of an operator.
[0098]
According to the pile verticality management device according to the second aspect of the present invention, by calculating the target straight length of the arm in consideration of the lifting and pitching angle of the holding body, the verticality of the pile is maintained more correctly. Can be.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an entire configuration of a pile verticality management device according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a functional configuration of a main part of the above.
FIG. 3 is a schematic diagram showing an entire configuration of a pile verticality management device at the time of casting.
FIG. 4 is a schematic explanatory view showing an enlarged form of an arm 5 of the pile verticality management device at the time of casting.
FIG. 5 is a front view of the display showing a state where the reference posture of the pile core is determined.
FIG. 6 is a front view of the display showing a state when the construction final posture is stored.
FIG. 7 is a front view of the display showing a state when the pile core is pulled up to a predetermined height.
FIG. 8 is a front view of a display device showing a state at the time of starting the pile entry construction work.
FIG. 9 is a front view of the display showing a state before the length of the arm is correctly adjusted.
FIG. 10 is a front view of the display showing a state when the length of the arm is adjusted correctly.
FIG. 11 is a front view of the display showing a state when the parameter setting screen is displayed.
FIG. 12 is a flowchart showing an operation procedure until the pile core is pushed in.
[Explanation of symbols]
2 Pillar truck (holding body)
5 arm
6 pivot points
15 pile core (pile)
25 Encoder (arm length detection means)
29 arm inclinometer (first arm angle detection means)
30 Vehicle inclinometer (incline detecting means)
31 arm inclinometer (second arm angle detection means)
32 Arm deflection correction means
35 arithmetic processing unit (control means)

Claims (2)

A pile verticality management device that pivots around a pivot portion at a base end so as to be able to move up and down, and manages the verticality of a pile attached to the distal end of a telescopic arm,
Arm length detecting means for detecting the bending length from the pivot portion along the arm to the tip,
First arm angle detection means for detecting the undulation angle of the arm base end,
A second arm angle detecting means for detecting the undulation angle of the arm tip,
Based on the detection outputs from the arm length detecting means, the first arm angle detecting means and the second arm angle detecting means, a true straight line length from the pivot portion of the arm to the tip is calculated, and the straight line and the horizontal plane are calculated. Arm deflection correction means for calculating the true undulation angle between
From the distance along the horizontal plane from the pivot portion to the pile when the pile is located on the vertical line of the penetration position and the true undulation angle, the arm of which the pile is located on the vertical line of the penetration position is Control means for calculating a target straight length from the pivot portion to the tip end. The arm deflection correction unit further includes a tilt detection unit that detects a tilt of a holding body that holds the arm. The pile verticality management device according to claim 1, wherein the true straight length and the true undulation angle are calculated by subtracting a floating angle of the holding body when pushed into the ground.

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