JP3423704B2 - Construction method of large diameter improved soil column - Google Patents
Construction method of large diameter improved soil columnInfo
- Publication number
- JP3423704B2 JP3423704B2 JP2001305092A JP2001305092A JP3423704B2 JP 3423704 B2 JP3423704 B2 JP 3423704B2 JP 2001305092 A JP2001305092 A JP 2001305092A JP 2001305092 A JP2001305092 A JP 2001305092A JP 3423704 B2 JP3423704 B2 JP 3423704B2
- Authority
- JP
- Japan
- Prior art keywords
- discharge port
- blade
- excavation
- stirring
- solidified material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
Description
【発明の詳細な説明】
【0001】
【産業上の利用分野】この発明は、地盤の現位置掘削土
に固化材を添加して機械的に混合攪拌し、化学的に固化
した改良土柱を築造する地盤改良工法において、改良径
が例えば1.5mを超えるような大口径の改良土柱の築
造方法に関するものである。
【0002】
【従来の技術】深層混合地盤改良工法においては、一般
に、ベースマシンに掘削軸を回転掘進可能に設け、この
掘削軸の先端に掘削翼,攪拌翼,固化材吐出口などを設
けた掘削攪拌装置を使用し、例えば掘削軸を回転掘進さ
せて所定の深度に達すると、スラリー状の固化材を吐出
しつつ掘進・混合攪拌を行い、最下端まで達すると、掘
削軸を逆転させて引き上げながら再び混合攪拌し、地盤
中に改良土柱を築造している。
【0003】このような掘削攪拌装置を用いて、大口径
の改良土柱を築造する場合、掘削翼や攪拌翼に関して
は、その長さを単純に大きくすることで対応することが
できる。一方、固化材スラリーの吐出に関しては、改良
径が1.2m〜1.5m程度までであれば、セメントミ
ルク等の固化材スラリーを掘削軸の先端部における側面
に設けた吐出口から低圧で吐出する構成で、掘削孔横断
面内で均一に分散させ攪拌混合することが可能である。
しかし、1.5mを超えるような大口径の改良土柱を築
造するためには、固化材スラリーを掘削孔横断面全体に
均一に行き渡るように配慮することが肝要となる。
【0004】掘削攪拌装置としては、従来から種々の装
置が開発されているが、固化材スラリーを掘削土横断面
全体に均一に行き渡らせる技術としては、例えば次のよ
うなものが提案されている。
【0005】 掘削翼ガイド方式
例えば、特開平7−76826号公報(切削混合機)に
記載されているように、掘削軸の先端に、下向き樋状の
カッタースポークと樋内に配列した多数の切刃からなる
掘削翼を取付け、掘削軸内の供給管内を供給されるセメ
ントミルクを掘削軸先端に設けた拡散板で受けると同時
に水平方向に拡散し、このセメントミルクを樋状のカッ
タースポーク内ガイド空間に導き、カッタースポーク全
体にセメントミルクを行き渡らせるものである。
【0006】 吐出口の位置を掘削翼や攪拌翼にまで
延長する方式
例えば、特開昭62−273316号公報(地盤改良装
置)では、掘削軸の先端部における攪拌翼あるいは掘削
翼に直径方向に間隔をおいて多数の吐出口を設けてい
る。また、特開平6−146264号公報(共回り防止
強制攪拌装置)では、セメントミルクを供給する供給管
を掘削翼まで延在させ、その先端の射出ノズルが掘削翼
の半径方向中央部に位置するようにしている。
【0007】
【発明が解決しようとする課題】前述の掘削翼ガイド方
式は、拡散板により水平に拡散させたセメントミルク
を、掘削翼をガイドとして全断面に均一に行き渡らせる
工夫をしているものの、セメントミルクを直接制御する
ことができない機構である。従って、セメントミルクが
全断面均一に攪拌混合する場合もあるが、うまく行かな
い場合もあるという欠点を有し、確実性に欠けるため、
大口径の改良土柱には適用し難い。
【0008】また、前述の攪拌翼に多数の吐出口を設け
る方式では、各吐出口からの吐出量が掘削軸から離れる
に従って少なくなり、均一な攪拌混合ができないという
欠点がある。さらに、掘削翼中央に射出ノズルを設ける
方式では、掘削土横断面の外側部分についてはセメント
ミルクが均一に充填されるが、逆に内側部分については
セメントミルクが供給されず、改良土柱全体が不均一な
改良体となる欠点があった。
【0009】この発明は、前述のような問題点を解消す
べくなされたもので、その目的は、大口径の改良土柱に
対しても固化材スラリーを掘削翼にて掘削された掘削土
横断面全体に均一に確実に行き渡らせることができ、掘
削翼にて掘削された断面全体にわたって均一な大口径改
良土柱を容易に築造することのできる築造方法を提供す
ることにある。
【0010】
【課題を解決するための手段】本発明は、掘削軸の先端
部分に掘削翼と攪拌翼を備えた掘削攪拌装置を用いて掘
削土に固化材液を添加しつつ混合攪拌して改良土柱を築
造する方法において、掘削軸の先端部分における下部に
吐出口を設け、この下部吐出口を、掘削軸の先端部分に
おける側面部に設けた吐出口と、掘削翼または攪拌翼の
半径方向中間部に設けた吐出口から構成すると共に、前
記半径方向中間部の吐出口は、掘削翼ま たは攪拌翼に設
けた水平供給管の先端に形成することにより掘削翼また
は攪拌翼の半径方向中間部に一箇所設け、かつ、平面視
で翼延在方向に対して直角の方向に向くようにし、これ
ら側面部と半径方向中間部の吐出口のそれぞれに独立し
た固化材液の供給通路を接続してなる大口径用掘削攪拌
装置を使用し、掘進攪拌時に前記下部吐出口の前記側面
部の吐出口と前記半径方向中間部の吐出口から固化材液
(セメントミルク等)を同時に吐出して、側面部の吐出
口からの固化材液を掘削軸近傍の掘削土内側部分に供給
すると共に半径方向中間部の吐出口から固化材液を掘削
土外側部分に供給することにより改良土柱を築造するこ
とを特徴とする大口径改良土柱の築造方法である。
【0011】このような固化材液の吐出方法は、掘削・
攪拌ヘッドの貫入時(掘進,攪拌時)にのみ掘削軸の最
先端部分における下部(掘削翼付近)の下部吐出口から
吐出する方法である。従って、本発明は、貫入時のみ吐
出する場合であり、掘削軸の先端部分における下部(掘
削翼位置あるいは最下段の攪拌翼位置など)に下部吐出
口を設けることになる。
【0012】下部吐出口は、掘削翼あるいは攪拌翼の掘
削軸近傍と半径方向中央部に設けてもよいが、一つを掘
削軸の先端部分の側面に、他を掘削翼あるいは攪拌翼の
半径方向中間部に設けるのが、構造上の点などから好ま
しい。また、掘削軸側の内側吐出口と翼中間部の外側吐
出口とには、それぞれ独立した固化材液供給通路が接続
されるが、各固化材液供給通路には、掘削攪拌装置の外
部の固化材液タンクから個別に固化材液を供給可能と
し、各吐出口からそれぞれ任意の吐出量で固化材液が噴
出される。
【0013】
【作用】以上のような構成において、掘削軸側面の内側
吐出口および翼中間部の外側吐出口から固化材液が同時
に噴出され、内側吐出口からの固化材スラリー(固化材
液)が掘削軸近傍の掘削土内側部分に十分に供給され、
外側吐出口からの固化材スラリー(固化材液)が掘削土
の周囲部分まで到達して掘削土外側部分に十分に供給さ
れる。さらに、各吐出口のそれぞれに独立した固化材液
供給通路が接続されるため、各吐出口からの固化材液の
吐出量を口径の大きさに応じて任意に設定することによ
り、各吐出口から所定の吐出量だけを確実に吐出するこ
とができ、掘削攪拌装置の回転貫入時に、直径が1.5
mを超えるような大口径の改良土柱でも固化材液を掘削
翼にて掘削された横断面全体に均一に、かつ確実に行き
渡らせることができる。
【0014】
【実施例】以下、この発明を図示する一実施例に基づい
て説明する。図1は、この発明の築造方法で使用する大
口径用掘削攪拌装置における掘削軸の先端部分を示し、
図2はその横断面を示す。図1において、図示しない掘
削軸本体の先端部分に掘削攪拌ヘッドAが取付けられ、
この掘削攪拌ヘッドAの掘削軸1に、下から順に、掘削
軸先端の掘削ビット2と、複数の掘削刃を備えた二枚の
掘削翼3と、掘削軸1に対して回転自在に支持され固定
状態で土の共回りを阻止する共回り防止翼4と、複数段
の攪拌翼5とが取付けられている。
【0015】なお、掘削軸本体は上部に回転駆動装置を
有し、この回転駆動装置を介して装置本体のリーダに上
下移動可能に支持され、回転駆動装置を吊りワイヤロー
プで昇降させることにより、掘削・攪拌ヘッドが回転し
つつ掘進下降し、また引揚上昇する(図示省略)。
【0016】このような掘削攪拌ヘッドAにおいて、図
1,図2に示すように、掘削軸1の下端における側面に
吐出口10を設け、一対の掘削翼3の一方に吐出口11
を設け、内側の掘削軸吐出口10と外側の掘削翼吐出口
11により下部吐出口を構成する。掘削軸吐出口10
は、一対の掘削翼3の取付け部分の間に一箇所設け、掘
削翼吐出口11は、掘削軸1から掘削翼3の傾斜する裏
面に添設した水平供給管12の先端に形成することによ
り、掘削翼3の半径方向中央部に一箇所設ける。この実
施例では、掘削軸吐出口10と掘削翼吐出口11の吐出
方向は互いに反対方向となるようにしている(図2参
照)。
【0017】掘削軸吐出口10および掘削翼吐出口11
の水平供給管12には、それぞれ独立した固化材スラリ
ー(固化材液)供給通路13,14を接続する。この固
化材スラリー(固化材液)供給通路13,14は、掘削
軸1および掘削軸本体内に設けた供給管あるいは供給孔
などとし、掘削軸本体の上端部に設けたスイベル、ホー
ス等を介して、外部に設置したミキシングプラントのポ
ンプに接続し、各吐出口10,11に個別に固化材スラ
リー(固化材液)を供給可能とする。
【0018】また、ポンプは二台設置し、それぞれのポ
ンプに流量調整弁を介して掘削軸吐出口10用のホース
と掘削翼吐出口11用のホースを接続するなどして、各
吐出口10,11毎に吐出量を設定し、調整できるよう
にする。
【0019】なお、掘削軸吐出口10は、掘削軸1の対
向する側面に一対で配設してもよい。掘削翼吐出口11
は、もう一方の掘削翼3にも設けてもよい。また、掘削
翼吐出口11は最下段の攪拌翼5-1に水平供給管12’
を介して設け、この攪拌翼吐出口11’と掘削軸吐出口
10とにより下部吐出口を構成してもよい。さらに、掘
削軸吐出口10をなくし、最下段の攪拌翼5-1の近傍に
おける掘削軸1の側面に掘削軸吐出口10’を設け、こ
の掘削軸吐出口10’と攪拌翼吐出口11’とにより下
部吐出口を構成してもよい。
【0020】掘削軸吐出口10,10’あるいは翼吐出
口11,11’を、複数配設する場合には、複数個の吐
出口10,10’あるいは11,11’に共通の固化材
スラリー(固化材液)供給通路から固化材スラリー(固
化材液)を供給可能としてもよいし、複数個の吐出口1
0あるいは11に対して独立した固化材スラリー(固化
材液)供給通路をそれぞれ接続するようにしてもよい。
【0021】以上は、本発明で使用する下部吐出口の構
成についてのみ説明したが、引抜時吐出方法あるいは貫
入時・引抜時吐出方法を行う場合には、上部吐出口を設
ける。この上部吐出口は、下部吐出口と同様に、最上段
の攪拌翼5-4の取付け部分の若干上方における掘削軸1
の側面に設けた掘削軸吐出口10”と、この攪拌翼5-4
の半径方向中間部に水平供給管12”を介して設けた攪
拌翼吐出口11”から構成する。
【0022】なお、この掘削軸吐出口10”と攪拌翼吐
出口11”の場合も、下部吐出口と同様に、上部の適当
な位置にそれぞれ複数個配設する。攪拌翼の掘削軸近傍
と半径方向中央部に設けるなど種々の態様をとることが
できる。また、掘削軸吐出口10”と攪拌翼吐出口1
1”のそれぞれの固化材スラリー(固化材液)供給通路
13”および14”は、下部吐出口の固化材スラリー
(固化材液)供給通路13および14とそれぞれ別個独
立とする。
【0023】この場合には、例えば、13”と13を2
重管から構成して、13”を掘削軸吐出口10”に連通
し、13を掘削軸吐出口10に連通し、掘削軸本体の上
部に設けた流路切替装置により13”と13とを選択可
能とし、上部の掘削軸吐出口10”と下部の掘削軸吐出
口10とを任意に選択し、かつそれぞれから所定の吐出
量の固化材スラリー(固化材液)を噴出可能とする。1
4”と14も同様にする。
【0024】以上のような構成において、直径が1.5
mを超える改良土柱に対して、例えば次のような手順で
深層地盤改良を行う。
【0025】(1) 築造すべき改良土柱の径に応じて各吐
出口10,11からの吐出量をそれぞれ設定しておき、
掘削軸を回転させつつ下降させる。
【0026】(2) 所定の深度に達すると、固化材スラリ
ー(固化材液)を各吐出口10,11から同時に噴出し
つつ掘進・混合攪拌を行う。
【0027】(3) 貫入時吐出方法では、最下端まで達す
ると、掘削軸を逆転させて引き上げ、各吐出口10,1
1から固化材スラリー(固化材液)は圧送を停止して再
び混合攪拌を行う。
【0028】地盤改良区間から掘削軸を回転させつつ引
き揚げて、施工を終了する。
【0029】貫入時・引抜時吐出方法では、最下端まで
達すると、下部の吐出口10,11から上部の吐出口1
0”,11”に切替え、掘削軸を逆転させて引き上げな
がら、固化材スラリー(固化材液)を上部の吐出口1
0”,11”から同時に噴出しつつ再び混合攪拌を行
う。地盤改良区間の注入、攪拌、引揚が終了すると、各
吐出口10”,11”からの固化材スラリー(固化材
液)の噴出を停止し、掘削軸を回転させつつ引き揚げ
て、施工を終了する。
【0030】内側の掘削軸吐出口10あるいは10”と
外側の掘削翼吐出口11あるいは11”からそれぞれ個
別に設定された所要の吐出量で固化材スラリー(固化材
液)が噴出され、固化材スラリー(固化材液)が掘削翼
にて掘削された掘削土の横断面全体に均一に、かつ確実
に分散され、攪拌混合され、全体にわたって均一な改良
土柱が得られる。
【0031】なお、以上は深層地盤改良工法について説
明したが、これに限らず、その他の地盤改良工法にも本
発明を適用できることはいうまでもない。
【0032】
【発明の効果】前述の通り、この発明は、掘削軸の先端
部分に掘削翼と攪拌翼を備えた掘削攪拌装置を用いて掘
削土に固化材液を添加しつつ混合攪拌して改良土柱を築
造する方法において、掘削軸の先端部分における下部に
吐出口を設け、この下部吐出口を、掘削軸の先端部分に
おける側面部に設けた吐出口と、掘削翼または攪拌翼の
半径方向中間部に設けた吐出口から構成すると共に、前
記半径方向中間部の吐出口は、掘削翼または攪拌翼に設
けた水平供給管の先端に形成することにより掘削翼また
は攪拌翼の半径方向中間部に一箇所設け、かつ、平面視
で翼延在方向に対して直角の方向に向くようにし、これ
ら側面部と半径方向中間部の吐出口のそれぞれに独立し
た固化材液の供給通路を接続してなる大口径用掘削攪拌
装置を使用し、掘進攪拌時に前記側面部の吐出口と前記
半径方向中間部の吐出口から固化材液を同時に吐出し
て、側面部の吐出口からの固化材液を掘削軸近傍の掘削
土内側部分に供給すると共に半径方向中間部の吐出口か
ら固化材液を掘削土外側部分に供給することにより改良
土柱を築造するため、掘削攪拌装置の回転下降時に、掘
削土の内側と外側に固化材液を供給することができると
共に、それぞれの吐出量を任意に設定することができ、
大口径の改良土柱であっても、固化材液を掘削翼にて掘
削された断面全体にわたって均一に、かつ確実に行き渡
らせることができ、全体にわたって均一な大口径改良土
柱を容易に築造することができる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved soil column which has been chemically solidified by adding a solidifying material to the excavated soil at the current position of the ground, mechanically mixing and stirring it. The present invention relates to a method for building a large-diameter improved soil column having an improved diameter exceeding, for example, 1.5 m in a ground improvement method for building. 2. Description of the Related Art In a deep mixing ground improvement method, an excavation shaft is generally provided on a base machine so as to be rotatable and excavated, a stirring blade, a solidified material discharge port and the like are provided at the tip of the excavation shaft. Using a drilling and stirring device, for example, when the drilling shaft reaches a predetermined depth by rotating and drilling, the drilling and mixing and stirring is performed while discharging the solidified material in a slurry state, and when it reaches the bottom end, the drilling shaft is reversed. It is mixed and stirred again while pulling up, and an improved earth pillar is being built in the ground. [0003] When an improved earth column with a large diameter is constructed using such an excavating and stirring device, the length of the excavating blade and the stirring blade can be simply increased. On the other hand, regarding the discharge of the solidified material slurry, if the improved diameter is up to about 1.2 m to 1.5 m, the solidified material slurry such as cement milk is discharged at a low pressure from the discharge port provided on the side surface at the tip of the excavation shaft. With this configuration, it is possible to uniformly disperse and stir and mix in the cross section of the borehole.
However, in order to construct a large-diameter improved soil column having a diameter exceeding 1.5 m, it is important to consider that the solidified material slurry is uniformly distributed over the entire cross section of the excavation hole. Various types of excavating and stirring devices have been developed in the past. As a technique for uniformly dispersing the solidified material slurry over the entire cross section of excavated soil, for example, the following technology has been proposed. . Drilling blade guide system [0005] As described in, for example, JP-A-7-76826 (cutting mixer), a downward gutter-shaped cutter spoke and a large number of cuts arranged in the gutter are provided at the tip of a drilling shaft. A drilling wing consisting of a blade is attached, and the cement milk supplied in the supply pipe in the drilling shaft is received by the diffusion plate provided at the tip of the drilling shaft and simultaneously diffuses horizontally, and this cement milk is guided in a gutter-like cutter spoke. It leads to the space and spreads the cement milk throughout the cutter spokes. [0006] A method of extending the position of the discharge port to a digging blade or a stirring blade, for example, in Japanese Patent Application Laid-Open No. 62-273316 (ground improvement device), a diametrical direction is applied to the stirring blade or the digging blade at the tip of the digging shaft. A large number of discharge ports are provided at intervals. In JP-A-6-146264 (co-rotation prevention forced stirring device), a supply pipe for supplying cement milk extends to a drilling wing, and an injection nozzle at the tip thereof is located at a radially central portion of the drilling wing. Like that. [0007] The above-mentioned excavation wing guide system is designed to uniformly spread the cement milk spread horizontally by the diffusion plate over the entire cross section using the excavation wing as a guide. It is a mechanism that cannot directly control cement milk. Therefore, although the cement milk may be stirred and mixed uniformly over the entire cross section, it has a disadvantage that it may not work well, and lacks certainty.
It is difficult to apply to large-diameter improved soil columns. In addition, the above-described method in which a number of discharge ports are provided in the stirring blade has a disadvantage that the discharge amount from each discharge port decreases as the distance from the excavation axis decreases, and uniform stirring and mixing cannot be performed. Furthermore, in the method in which the injection nozzle is provided at the center of the excavation wing, cement milk is uniformly filled in the outer portion of the excavated soil cross section, but conversely, cement milk is not supplied in the inner portion, and the entire improved soil column is There is a disadvantage that it results in a non-uniform improvement. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to traverse excavated soil in which a solidified material slurry is excavated by an excavation wing even for an improved soil column having a large diameter. It can be uniformly spread to ensure the entire surface, drilling
An object of the present invention is to provide a construction method capable of easily constructing a uniform large-diameter improved earth column over the entire cross section excavated by a blade . According to the present invention, a solidifying material liquid is added to excavated soil by mixing and stirring while using an excavating and stirring apparatus provided with an excavating blade and a stirring blade at the tip of an excavating shaft. In the method for constructing an improved earth column, a discharge port is provided at a lower portion at a tip portion of a drilling shaft, and the lower discharge port is provided with a discharge port provided at a side portion at a tip portion of the drilling shaft, and a radius of a drilling blade or a stirring blade. together constituting the discharge port formed in a direction intermediate portion, the discharge port of the radial intermediate portion, setting the excavation blade or the stirring blade
Drilling wings or
Is provided at one point in the radial middle part of the stirring blade, and is oriented in a direction perpendicular to the blade extending direction in a plan view. Using a large-diameter excavating and stirring device connected to a material liquid supply passage, and the side surface of the lower discharge port when excavating and stirring.
Wherein a part of the discharge port radially intermediate portion solidifying material liquid from the discharge port of ejected (cement milk or the like) at the same time, discharge of the side surface portion
Supply solidified material liquid from the mouth to the inside of the excavated soil near the excavation axis
And solidified material liquid is excavated from the discharge port at the middle part in the radial direction.
This is a method for constructing a large-diameter improved soil column, characterized in that an improved soil column is built by supplying the soil to an outside portion of the soil. [0011] Such a method of discharging the solidified material liquid involves excavation and
In this method, only when the stirring head penetrates (drilling and stirring), the liquid is discharged from the lower discharge port at the lowermost portion (near the excavation wing) of the excavation shaft. Therefore, the present invention is a case where the discharge is performed only at the time of penetration, and a lower discharge port is provided at a lower portion (a position of the excavation blade or a position of the lowermost stirring blade) at the tip of the excavation shaft. The lower discharge port may be provided in the vicinity of the excavation axis of the excavation blade or the stirring blade and at the center in the radial direction. It is preferable to provide it in the middle part in the direction from the viewpoint of the structure. Also, independent solidified material liquid supply passages are connected to the inner discharge port on the excavation shaft side and the outer discharge port in the middle of the blade, respectively. The solidified material liquid can be individually supplied from the solidified material liquid tank, and the solidified material liquid is ejected from each discharge port at an arbitrary discharge amount. In the above construction, the solidified material liquid is simultaneously ejected from the inner discharge port on the side surface of the excavation shaft and the outer discharge port on the intermediate portion of the blade, and the solidified material slurry (solidified material liquid) is discharged from the inner discharge port. Is sufficiently supplied to the inside of the excavated soil near the excavation axis,
The solidified material slurry (solidified material liquid) from the outer discharge port reaches the surrounding portion of the excavated soil and is sufficiently supplied to the outer portion of the excavated soil. Further, since an independent solidified material liquid supply passage is connected to each of the discharge ports, the discharge amount of the solidified material liquid from each of the discharge ports is arbitrarily set according to the size of the diameter, so that each of the discharge ports is , A predetermined discharge amount can be reliably discharged from the drilling and stirring device.
Drilling of solidified material liquid even for large-diameter improved soil columns exceeding m
It can be uniformly and reliably spread over the entire cross section excavated by the wing . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 shows a tip portion of a drilling shaft in a large diameter drilling and stirring device used in the construction method of the present invention,
FIG. 2 shows the cross section. In FIG. 1, a digging and stirring head A is attached to a tip portion of a digging shaft body (not shown),
An excavating shaft 1 of the excavating and stirring head A is supported, in order from the bottom, on an excavating bit 2 at the tip of the excavating shaft, two excavating blades 3 having a plurality of excavating blades, and a rotatable shaft with respect to the excavating shaft 1. A co-rotation prevention blade 4 for preventing co-rotation of soil in a fixed state and a plurality of stages of stirring blades 5 are attached. The excavating shaft main body has a rotary driving device at an upper portion, and is supported by a leader of the device main body via the rotary driving device so as to be vertically movable, and the rotary driving device is raised and lowered by a hanging wire rope. The excavation / stirring head rotates and excavates and descends, and also lifts and rises (not shown). In such an excavating and stirring head A, as shown in FIGS. 1 and 2, a discharge port 10 is provided on a side surface at the lower end of the excavating shaft 1, and a discharge port 11 is provided on one of a pair of excavating blades 3.
And the lower discharge port is constituted by the inner excavation axis discharge port 10 and the outer excavation blade discharge port 11. Drilling shaft discharge port 10
Is provided at one location between the mounting portions of the pair of digging wings 3, and the digging wing discharge port 11 is formed at the tip of a horizontal supply pipe 12 attached to the inclined back surface of the digging wing 3 from the digging shaft 1. And one location at the radial center of the excavation wing 3. In this embodiment, the discharge directions of the excavation shaft discharge port 10 and the excavation blade discharge port 11 are set to be opposite to each other (see FIG. 2). Drilling shaft discharge port 10 and drilling blade discharge port 11
The solid supply material slurry (solidification material liquid) supply passages 13 and 14 are respectively connected to the horizontal supply pipe 12. The solidified material slurry (solidified material liquid) supply passages 13 and 14 are a supply pipe or a supply hole provided in the excavation shaft 1 and the excavation shaft main body, and are connected via a swivel, a hose, or the like provided at an upper end portion of the excavation shaft main body. Then, it is connected to a pump of a mixing plant installed outside, so that a solidified material slurry (solidified material liquid) can be individually supplied to each of the discharge ports 10 and 11. Further, two pumps are installed, and a hose for the excavation shaft discharge port 10 and a hose for the excavation blade discharge port 11 are connected to each pump via a flow rate control valve. , 11 are set and adjusted. The excavation shaft discharge ports 10 may be provided as a pair on opposing side surfaces of the excavation shaft 1. Drilling wing discharge port 11
May be provided on the other excavation wing 3. Further, the excavation blade discharge port 11 is connected to the horizontal supply pipe 12 ′ to the lowermost stirring blade 5-1.
And the lower discharge port may be constituted by the stirring blade discharge port 11 ′ and the excavation axis discharge port 10. Furthermore, eliminating the drilling shaft discharge port 10, the drilling shaft discharge port 10 on the side surface of the excavating shaft 1 in the vicinity of the lowermost stirring blade 5 -1 'to provided, the drilling shaft discharge port 10' and the stirring blade discharge port 11 ' The lower discharge port may be constituted by the above. When a plurality of excavation shaft discharge ports 10, 10 'or blade discharge ports 11, 11' are provided, a solidified material slurry (common to the plurality of discharge ports 10, 10 'or 11, 11') is used. A solidified material slurry (solidified material liquid) may be supplied from a supply passage, or a plurality of discharge ports 1 may be supplied.
An independent solidification material slurry (solidification material liquid) supply passage may be connected to 0 or 11, respectively. Although only the configuration of the lower discharge port used in the present invention has been described above, the upper discharge port is provided when the discharge method at the time of pull-out or the discharge method at the time of penetration or pull-out is performed. The upper discharge port is, like the lower discharge port, provided with the excavation shaft 1 slightly above the mounting portion of the uppermost stirring blade 5-4.
And a stirring blade 5-4
And a stirring blade discharge port 11 "provided at a radially intermediate portion through a horizontal supply pipe 12". In addition, in the case of the excavating shaft discharge port 10 "and the stirring blade discharge port 11", similarly to the lower discharge port, a plurality of the excavation shaft discharge ports are arranged at appropriate upper positions. Various modes can be adopted, such as providing the stirring blade near the excavation axis and at the center in the radial direction. Also, the excavation shaft discharge port 10 ″ and the stirring blade discharge port 1
The solidified material slurry (solidified material liquid) supply passages 13 "and 14" of 1 "are respectively independent of the solidified material slurry (solidified material liquid) supply passages 13 and 14 of the lower discharge port. In this case, for example, 13 ″ and 13 are 2
13 ″ communicates with the drilling shaft discharge port 10 ″, 13 communicates with the drilling shaft discharge port 10, and 13 ″ and 13 are connected by a flow path switching device provided at the upper part of the drilling shaft body. The upper excavation shaft discharge port 10 ″ and the lower excavation shaft discharge port 10 are arbitrarily selected, and a predetermined amount of solidified material slurry (solidified material liquid) can be ejected from each of them. 1
The same applies to 4 "and 14. In the above configuration, the diameter is 1.5.
For improved soil columns exceeding m, deep ground improvement is performed by the following procedure, for example. (1) The discharge amount from each of the discharge ports 10 and 11 is set according to the diameter of the improved earth pillar to be built,
The drilling shaft is lowered while rotating. (2) When a predetermined depth is reached, solidification material slurry (solidification material liquid) is simultaneously ejected from each of the discharge ports 10 and 11, and excavation and mixing and stirring are performed. (3) In the discharge method at the time of penetration, when reaching the lowermost end, the excavation axis is reversed and pulled up, and each of the discharge ports 10, 1
From 1, the solidified material slurry (solidified material liquid) is stopped from being fed under pressure and mixed and stirred again. The construction is completed by pulling up from the ground improvement section while rotating the excavation shaft. In the discharge method at the time of penetration or withdrawal, when reaching the lowermost end, the lower discharge ports 10 and 11 are moved from the upper discharge port 1 to the upper discharge port 1.
0 ”, 11”, and while the excavation axis is reversed and pulled up, the solidified material slurry (solidified material liquid) is discharged to the upper discharge port 1.
Mixing and stirring are performed again while simultaneously jetting from 0 ″ and 11 ″. When the injection, agitation, and withdrawal of the ground improvement section are completed, the ejection of the solidified material slurry (solidified material liquid) from each of the discharge ports 10 "and 11" is stopped, the excavation shaft is rotated while being lifted, and the construction is completed. . A solidified material slurry (solidified material liquid) is ejected from the inner excavation shaft discharge port 10 or 10 "and the outer excavation blade discharge port 11 or 11" at a predetermined discharge amount individually set, and the solidified material slurry is discharged. Slurry (solidified material liquid) is excavated
Is uniformly and reliably dispersed throughout the cross section of the excavated soil excavated in the above , and agitated and mixed to obtain a uniform improved soil column throughout. Although the deep ground improvement method has been described above, it goes without saying that the present invention is not limited to this and can be applied to other ground improvement methods. As described above, according to the present invention, the excavated soil is added to the excavated soil by mixing and agitating while adding the solidified material liquid using the excavated agitating device having the excavated blade and the agitating blade at the tip of the excavated shaft. In the method for constructing an improved earth column, a discharge port is provided at a lower portion at a tip portion of a drilling shaft, and the lower discharge port is provided with a discharge port provided at a side portion at a tip portion of the drilling shaft, and a radius of a drilling blade or a stirring blade. And a discharge port provided in the middle part in the radial direction, and the discharge port in the middle part in the radial direction is provided in a drilling blade or a stirring blade.
Drilling wings or
Is provided at one point in the radial middle part of the stirring blade, and is oriented in a direction perpendicular to the blade extending direction in a plan view. using the timber liquid large diameter drilling stirring device a supply passage formed by connecting the, simultaneously discharging the solidified material liquid from the discharge port of the radial intermediate portion to the discharge port of the side surface portion during excavation stirring
To extrude the solidified material liquid from the discharge port on the side
Supplied to the inside of soil
In order to build the improved soil column by supplying the solidified material liquid to the outside of the excavated soil, the solidified material liquid can be supplied to the inside and outside of the excavated soil when the excavation stirrer rotates and lowered, and The discharge amount can be set arbitrarily,
Excavation of solidified material with excavation wings even for large-diameter improved soil columns
It can be uniformly and reliably spread over the entire cut cross section, and a large-diameter improved earth pillar uniform over the entire cross section can be easily constructed.
【図面の簡単な説明】
【図1】この発明の築造方法で使用する大口径用掘削攪
拌装置の先端部分の一実施例を示す側面図である。
【図2】図1の横断面図である。
【符号の説明】
1…掘削軸
2…掘削ビット
3…掘削翼
4…共回り防止翼
5…攪拌翼
10…掘削軸吐出口
11…掘削翼吐出口
12…水平供給管
13…掘削軸吐出口用の固化材スラリー(固化材液)供
給通路
14…掘削翼吐出口用の固化材スラリー(固化材液)供
給通路BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing one embodiment of a distal end portion of a large-diameter excavating and stirring apparatus used in the construction method of the present invention. FIG. 2 is a cross-sectional view of FIG. [Description of Signs] 1 ... Drilling shaft 2 ... Drilling bit 3 ... Drilling blade 4 ... Co-rotation prevention blade 5 ... Stirring blade 10 ... Drilling shaft discharge port 11 ... Drilling blade discharge port 12 ... Horizontal supply pipe 13 ... Drilling shaft discharge port Solidified material slurry (solidified material liquid) supply passage 14 ... solidified material slurry (solidified material liquid) supply passage for excavation blade discharge port
Claims (1)
えた掘削攪拌装置を用いて掘削土に固化材液を添加しつ
つ混合攪拌して改良土柱を築造する方法において、 掘削軸の先端部分における下部に吐出口を設け、この下
部吐出口を、掘削軸の先端部分における側面部に設けた
吐出口と、掘削翼または攪拌翼の半径方向中間部に設け
た吐出口から構成すると共に、前記半径方向中間部の吐
出口は、掘削翼または攪拌翼に設けた水平供給管の先端
に形成することにより掘削翼または攪拌翼の半径方向中
間部に一箇所設け、かつ、平面視で翼延在方向に対して
直角の方向に向くようにし、これら側面部と半径方向中
間部の吐出口のそれぞれに独立した固化材液の供給通路
を接続してなる大口径用掘削攪拌装置を使用し、掘進攪
拌時に前記下部吐出口の前記側面部の吐出口と前記半径
方向中間部の吐出口から固化材液を同時に吐出して、側
面部の吐出口からの固化材液を掘削軸近傍の掘削土内側
部分に供給すると共に半径方向中間部の吐出口から固化
材液を掘削土外側部分に供給することにより改良土柱を
築造することを特徴とする大口径改良土柱の築造方法。(57) [Claims 1] An improved soil by mixing and stirring while adding a solidifying material liquid to an excavated soil using an excavating and stirring device provided with an excavating blade and a stirring blade at a tip portion of an excavating shaft. In the method of constructing a pillar, a discharge port is provided at a lower portion at a tip portion of a drilling shaft, and the lower discharge port is provided between a discharge port provided at a side portion at a tip portion of the drilling shaft and a radially intermediate portion of a drilling blade or a stirring blade. And a discharge port in the middle part in the radial direction is provided at the tip of a horizontal supply pipe provided on a cutting blade or a stirring blade.
Formed in the radial direction of the drilling blade or stirring blade
Provided at one location in the intervening portion, and oriented in a direction perpendicular to the blade extending direction in plan view, the supply passage for the solidified material liquid is provided independently for each of these side portions and the radially intermediate discharge port. Using a large-diameter excavation and stirring device connected, the excavation port and the radius of the side portion of the lower discharge port during excavation and stirring
Simultaneously discharging the solidified material liquid from the discharge port direction intermediate portion, the side
The solidified material liquid from the discharge port of the surface is excavated inside the excavation soil near the excavation axis
And solidified from the discharge port in the middle part in the radial direction
A method for constructing a large-diameter improved soil column, comprising constructing an improved soil column by supplying a material liquid to an outer portion of the excavated soil .
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2001305092A JP3423704B2 (en) | 2001-10-01 | 2001-10-01 | Construction method of large diameter improved soil column |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2001305092A JP3423704B2 (en) | 2001-10-01 | 2001-10-01 | Construction method of large diameter improved soil column |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP14453595A Division JP3464076B2 (en) | 1995-06-12 | 1995-06-12 | Excavation stirrer for large diameter |
Publications (2)
Publication Number | Publication Date |
---|---|
JP2002115246A JP2002115246A (en) | 2002-04-19 |
JP3423704B2 true JP3423704B2 (en) | 2003-07-07 |
Family
ID=19124934
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Application Number | Title | Priority Date | Filing Date |
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JP2001305092A Expired - Lifetime JP3423704B2 (en) | 2001-10-01 | 2001-10-01 | Construction method of large diameter improved soil column |
Country Status (1)
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JP (1) | JP3423704B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106501490A (en) * | 2016-12-15 | 2017-03-15 | 中国农业科学院农业资源与农业区划研究所 | A kind of small-sized detachable earth pillar simulation device |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP7333535B1 (en) | 2022-11-30 | 2023-08-25 | 株式会社富士建 | Equipment for soil improvement by medium-pressure jet stirring, ground improvement method by medium-pressure jet stirring |
-
2001
- 2001-10-01 JP JP2001305092A patent/JP3423704B2/en not_active Expired - Lifetime
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106501490A (en) * | 2016-12-15 | 2017-03-15 | 中国农业科学院农业资源与农业区划研究所 | A kind of small-sized detachable earth pillar simulation device |
CN106501490B (en) * | 2016-12-15 | 2019-05-21 | 中国农业科学院农业资源与农业区划研究所 | A kind of small-sized detachable earth pillar simulation device |
Also Published As
Publication number | Publication date |
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JP2002115246A (en) | 2002-04-19 |
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