JP2671981B2

JP2671981B2 - Ground improvement material injection device

Info

Publication number: JP2671981B2
Application number: JP62175724A
Authority: JP
Inventors: 満生原
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-07-13
Filing date: 1987-07-13
Publication date: 1997-11-05
Anticipated expiration: 2012-11-05
Also published as: JPS6417917A

Description

【発明の詳細な説明】（イ）産業上の利用分野この発明は、地盤改良材注入装置に関する。（ロ）従来の技術従来、軟弱地盤を改良する方法として、同地盤に穿設
した掘削孔中の掘削土にモルタル等の硬化材を注入撹拌
して、この混練物の硬化により地盤強度を高めるという
工法があった。また、軟弱地盤を改良するために回転軸の下端に堀削
刃体と撹拌翼を連設し、同刃体による堀削孔中にて、堀
削土と、別途に注入したモルタル等の硬化剤によって軟
弱地盤の改良を行う地盤改良装置があった。（ハ）発明が解決しようとする問題点しかしながら、改良を要する地盤は、地質的には堆積
層の場合が多く、かかる堆積層は微細粒のシルト層、又
はピート層、あるいは、種々の土質で互層状に構成され
ている場合が多く、例えば、細粒状の砂層と、微細粒の
シルト層との互層で構成された地層に対して、セメント
系の硬化材を用いて地盤改良を行った場合、シルト層の
部分で硬化の結果が、砂層の部分よりも極端に劣るた
め、充分な地盤強度を得ることができず、そのため、同
強度上のバラツキが派生するという欠点があった。この
欠点を解消するために硬化材を過剰に混入することが行
われているが、これでは、充分な地盤強度及びバラツキ
を小さくすることはできず、また、ピート層に対して
は、硬化の効果を得るのに困難であった。また、かかる地盤に前以ってセメントと砂とを水で混
練したモルタルを注入して撹拌すると、モルタルが流動
性及び分散性が悪いために、掘削土組織の空隙にモルタ
ルが浸入して混合が完了するまでに時間がかかり、その
ため、混合撹拌途中の混合物の体積が増加して同混合物
が地表に溢れ出し圧密の効果が減少して地盤改良の効果
が充分でなく、更にこの溢れ出した掘削土を捨土するた
めに運搬しなければならず余分な作業が発生し、また、
モルタルの注入を停止すると注入装置内で砂とセメント
分とが分離して、爾後の作業に支障を来たすという欠点
があった。（ニ）問題点を解決するための手段この発明では、先端に掘削刃体及び撹拌翼を連設した
回転軸と硬化材供給装置とを具備して、回転軸の回転に
より地盤を掘削並びに掘削孔中の掘削土と地盤改良材と
を混合すべく構成した地盤改良装置において、回転軸を
それぞれ管状の内外軸よりなる二重軸に形成し、内外軸
の下端部にバルブケースを設け、同バルブケースに、内
外軸間に形成される空間と連通する供給弁と、外部と連
通する外吐出弁と、バルブケースと内軸とを連通する噴
射弁と、内軸の下端部を開閉する内吐出弁とを設け、各
弁を内外軸の相対回転方向の正逆により開閉切換可能に
連動連結し、かつ、供給弁と外吐出弁と噴射弁は同一の
開閉弁動作を行なうと共に、内吐出弁はこれら各弁とは
反対の開閉弁動作を行なうべく構成してなる地盤改良材
注入装置を提供せんとするものである。（ホ）作用・効果この発明によれば、地盤改良作業を行なう際には、回
転軸を回転させることにより、掘削刃体を回転させつつ
硬化させて、地中に略円柱形状の掘削孔を穿設すること
ができる。この際、掘削土の排出は行わず、掘削刃体及
び撹拌翼が掘削土中に埋没した状態とする。そして、上記の下降掘削作業中に、内軸中に水を圧入
し、回転軸の回転方向を内軸に対して外軸を回転させる
ことにより、供給弁、外吐出弁及び噴射弁を開弁動作さ
せると共に、内吐出弁を閉弁動作させることにより、噴
射弁からバルブケース中に噴射された水により、同バル
ブケース中に内軸と外軸との間に形成される空間より供
給弁を介して供給された砂等の粉粒体を、外吐出弁を介
して外部に吐出させることができ、同粉粒体を撹拌翼に
よって掘削土と混和させることができる。この際、粉粒体は、噴射水により強制的に、かつ、円
滑に吐出させることができると共に、水混じりの粉粒体
は撹拌翼により掘削土とスムーズに混和させることがで
きる。次いで、回転軸を逆回転させながら同回転軸を上昇さ
せることにより、供給弁、外吐出弁及び噴射弁を閉弁動
作させると共に、内吐出弁を開弁動作させて、内軸の先
端からセメントミルク等の硬化材を、前記のように前処
理した掘削土と砂の混合土中に注入して、これらを撹拌
翼により撹拌することができる。次いで、硬化材の注入を継続させながら回転軸を下降
させて、前工程で注入したセメントミルクと掘削土との
混練を行い、最後に回転軸を引き上げつつ仕上の撹拌を
行うことができる。このように、掘削孔中の掘削土に、まず粒粉体のみ混
入撹拌することで、硬化材の混入撹拌に先立って土質を
改良し、また掘削土の組織中への粒粉体の分散が速やか
に行われて混合撹拌の混合物の体積増加を抑止するの
で、掘削土の地表への溢れ出しが抑制されて捨土作業が
不要となると共に、圧密効果が充分に高くなる。その結果前以って土質の改良を行った掘削土に硬化材
の混練が均一に行われることになり、地盤改良結果のバ
ラツキも解消される。なお、前記したように、前以ってセメントと砂とを水
で混練したモルタルは、流動性及び分散性が悪く、混合
に時間がかかるものであるが、粒粉体の単体は、粘着性
がなく、またモルタルに比べて流動性及び分散性がよい
ことから、掘削土中への侵入つまり混合が円滑かつ短時
間で行われるものである。（ヘ）実施例本発明の実施例を図面にもとづき詳説すれば、（Ａ）
は地盤改良装置を示し、同装置（Ａ）は移動自在のベー
スマシン（１）、硬化材供給装置（２）により構成され
ており、ベースマシン（１）はリーダー（３）により回
転軸（４）を垂直に支持し、リーダー（３）と回転軸
（４）との間に介設したモーター（５）により回転軸
（４）と、同軸（４）下端に連設した堀削刃体（６）及
び撹拌翼（７）を回転させつつリーダー（３）に沿って
同軸（４）を降下せしめて、地盤（Ｇ）に垂直な堀削孔
（Ｈ）を穿設するように構成している。回転軸（４）は、二重軸、すなわち中空管状の外軸
（９）と、同外軸（９）の内部を挿通した内軸（10）に
より構成されており、回転軸（４）の上端とモーター
（５）との間に介設した二重反転歯車機構（11）によっ
て内外軸（10）（９）が相互に反対方向に回転するよう
に構成されており、内軸（10）は外軸（９）よりも更に
下方に延出して、同内軸（10）下端には堀削刃体（６）
が連設されている。堀削刃体（６）の上方には、撹拌翼（７）が配設され
ており、撹拌翼（７）は大・中・小撹拌翼体（7a）（7
b）（7c）にて構成されており、各翼体（7a）（7b）（7
c）は側面から見て略台形枠状に形成され、回転軸
（４）を中心として、それぞれ放射状に所定個数配設さ
れている。小撹拌翼体（7c）は、同翼体（7c）の上下端が外軸
（９）の下端部に固着されており、中撹拌翼体（7b）は
小撹拌翼体（7c）よりも大なる略台形枠状に形成され、
小撹拌翼体（7c）の外側を囲繞した状態で配設されてお
り、中撹拌翼体（7b）の下端は内軸（10）の下端に固着
され、同上端は小撹拌翼体（7c）上端の固着位置の上方
にて外軸（９）に軸支されており、大撹拌翼体（7a）は
中撹拌翼体（7b）の外側を囲繞して、その上端を外軸
（９）に固着させ、同下端を内軸（10）にて軸支してい
る。従って、中撹拌翼体（7b）は大小撹拌翼体（7a）（7
c）の中間でこれらとは反対方向に回転することにな
る。また、回転軸（４）の下端部には第２図で示す地盤改
良材注入装置（Ｂ）が設けられており、同装置（Ｂ）
は、外軸（９）の上端に、中空管状の外軸（９）の内部
と連通したホッパー（14）（第１図参照）を設けてお
り、ホッパー（14）下方の内軸（10）の外周面には、ス
クリュー（15）を連設して、外軸（９）よりも小径の搬
送内筒（16）にて囲繞し、同内筒（16）の上端縁を略漏
斗状の整形筒（17）を介して外軸（９）の内周面と連結
し、同下端は下方に開口せしめて、同開口端縁を斜めに
切欠している。従って、後記の円板（12）上に落下堆積する粒粉体
（８）が自己調圧作用により搬送内筒（16）下端の斜め
切欠開口端の上端よりも上方へは盛上らない。更に、搬送内筒の下方には、第３図、第４図で示すよ
うに、内軸（10）の外周面に略リング状の円板（12）を
連設して外軸（９）内周面と内軸（10）外周面とで形成
された空間の下端を閉塞しており、同円板（12）の下面
に略リング状のバルブ円板（13）を内軸（10）及び外軸
（９）まわりに回動自在に周設させて供給弁（38）を構
成しており、同弁（38）は双方の円板（12）（13）に同
形状の上下バルブ孔（18）（18′）を穿設して、両方の
孔位置が一致したときは、円板（12）上に堆積した粒粉
体（８）が下方に流出し、一致しないときは粒粉体
（８）の流下を停止させるようにしている。そして、円板（12）に対しバルブ円板（13）を回動さ
せるために、バルブ円板（13）の下面に枢軸（19）を突
設し、同枢軸（19）に略へ字形状の係合爪（20）の基端
を回動自在に枢着し、同爪（20）の先端（20a）を外側
方に付勢（21）して、同先端（20a）を外軸（９）の内
周面に摺接させると共に、外軸（９）の内周面に係合突
起（22）を突設して、第３図上において内軸（10）に対
して外軸（９）が左回転する際は、係合爪の先端（20
a）に係合突起（22）が当接しても、同爪先端（20a）が
内側方向に逃げて同突起（22）を素通りさせ、右回転の
場合は係合突起（22）が同爪先端（20a）と外軸（９）
内周面との間に喰い込んで、同爪（20）を介してバルブ
円板（13）を右回動させる。なお、バルブ円板（13）には、内軸（10）を中心とし
た略円弧状の長孔（23）を穿設しており、同長孔（23）
に円板（12）の下面に突設したエスケープピン（24）を
挿入して、円板（12）に対するバルブ円板（13）の回動
範囲を上下バルブ孔（18）（18′）の開閉に充分なスト
ロークに制限しており、更に同ピン（24）は、長孔（2
3）の終端位置において、同ピン（24）の側面が係合爪
（20）の屈折内側端面（20b）に当接して同爪（20）の
先端（20a）を押し上げ、同先端（20a）と係合突起（2
2）との係合を解除するようにしている。そして、上記のような係合爪（20）は、長孔（23）の
両端に対称に配設されており、従って、内軸（10）に対
し外軸（９）が右回転のときは上下バルブ孔（18）（1
8′）を一致させて開状態とし、左回転のときは閉状態
とするものであり、外軸（９）の一方向の回転が継続し
ても、一旦開又は閉状態になるまでバルブ円板（13）が
回動すると長孔（23）中のエスケープピン（24）が係合
爪（20）の先端（20a）を押し上げているので係合突起
（22）が素通りして上記の開又は閉状態が保持され、開
閉状態の切換は内軸（10）対する外軸（９）の回転方向
の正逆切換によってのみ行われる。また、上記係合突起（22）は外軸（９）の内周面の等
分位置に多数配設しており、若し何等かの原因で上下バ
ルブ孔（18）（18′）が半開きの状態になっても、半開
きの状態では係合爪先端（20a）が係合可能の位置にあ
るため、次の係合突起（22）により直ちに所定の開又は
閉状態になるまでバルブ円板（13）を回動させることに
よって開閉状態保持を確実にしている。また、バルブ円板（13）の下方には、内軸（10）に連
設したバルブケース（25）を設けており、同ケース（2
5）は、有底の略円筒状で同ケース（25）の上端縁は、
同ケース（25）の内部に内軸（10）を中心として回動自
在に収納したバルブ筒体（26）の上端部を中間に介在さ
せて外軸（９）の下端部とオーバーラップしている。バルブケース（25）とバルブ筒体（26）との間には外
吐出弁（27）が構成されており、同弁（27）はバルブ筒
体（26）とバルブケース（25）の側面にそれぞれ略方形
状の内外バルブ孔（28′）（28）を設け、両方のバルブ
孔（26a）（25a）位置が一致すると同弁（27）が開き、
一致しないときは同弁（27）を閉じるようにしており、
バルブケース（25）に対してバルブ筒体（26）を回動さ
せるために第５図、第６図の展開図で示すようにバルブ
筒体（26）の内側面に枢軸（19′）を突設し、同枢軸
（19′）に略三角形状の係合爪（20′）の基端を回動自
在に枢着し、同爪（20′）の先端（20′ａ）を、外軸
（９）の外側面に突設した係合突起（22′）を突設し
て、第４図上においてバルブケース（25）に対し外軸
（９）が左方向に回動する際は、係合爪の先端（20′
ａ）が係合突起（22′）に当接しても同爪先端（20a）
が上方向に逃げて同突起（22′）を素通りさせ、右方向
回動の場合は係合突起（22′）が同爪先端（20′ａ）と
係合してバルブ筒体（26）を右方向に回動させる。なお、バルブ筒体（26）の側面には水平に長孔（2
3′）を穿設しており、同長孔（23′）にバルブケース
（25）の内側面に突設したエスケープピン（24′）を挿
入して、バルブケース（25）に対するバルブ筒体（26）
の回動範囲を内外バルブ孔（28′）（28）の開閉に充分
なストロークに制限しており、更に同ピン（24′）は長
孔（23′）の終端位置において、同ピン（24′）の側面
が係合爪（20′）の下端縁（20′ｂ）に当接して同爪
（20′）の先端（20a′）を押し上げ、同先端（20′
ａ）と係合突起（22′）との係合を解除するようにして
いる。そして、上記のような係合爪（20′）は長孔（23）の
両端に対称に配設されており、従って、内軸に対し外軸
（９）が右回転のときは内外バルブ孔（28′）（28）が
一致して外吐出弁（27）が開き、左回転のときは同弁
（27）を閉じるものであり、一旦開又は閉状態になるま
でバルブ筒体（26）が回動すると、外軸（９）が回転を
継続しても、長孔（23′）中のエスケープピン（24′）
が係合爪（20′）の先端（20′ａ）を押し上げているの
で、係合突起（22′）が素通して、上記の開又は閉状態
が保持され、開閉状態の切換は内軸（10）に対する外軸
（９）回転方向の正逆切換によってのみ行われる。また、バルブケース（25）の内底面位置に当る内軸
（10）側壁に切欠部（29）を設けて、同切欠部（29）を
介してバルブ筒体（26）の底板（26a）の一部を内軸（1
0）の内部に延出（30）させており、延出部（30）と同
延出部（30）の下方の内軸（10）内側面に連設した閉塞
円板（31）との間に内吐出弁（32）を構成している。内吐出弁（32）は、延出部（30）を略円板状に形成し
て、同延出部（30）と閉塞円板（31）としてそれぞれ略
放射状に上下バルブ孔（33）（33′）を穿設し、バルブ
筒体（26）と一体の延出部の回動により内吐出弁（32）
を開閉させるようにしている。上記のように内外吐出弁（32）（27）は互いに連動し
て作動するのであるが、特に、各弁（32）（27）の開閉
作動を交互に、すなわち、内吐出弁（32）が開のときは
外吐出弁（27）が閉、内吐出弁（32）が閉のときは外吐
出弁（27）が開となるように各バルブ孔（28）（2
8′），（33）（33′）の位置を設定している。また、上記延出部（30）の上面には、内軸（10）の内
側面に近接して内筒（34）を立設し、内軸（10）と内筒
（34）との間に噴射弁（37）を構成しており、同弁（3
7）は内吐出弁（32）が閉のとき、同内筒（34）の側壁
に穿設した内噴射孔（35）を、バルブケース（25）の外
バルブ孔（28′）対向した内軸（10）側壁に穿設した外
噴射孔（35′）と一致させて内軸（10）の内部をバルブ
ケース（25）の内部に連通させるようにしている。なお、図中（36）は、液状硬化材を注入するためのホ
ースを示し、同ホース（36）は、硬化材供給装置（２）
中に内蔵した硬化材ポンプと連通しており、同ホース
（36）先端のスイベル（36a）を介し内軸（10）中に液
状硬化材又は水を圧入するものである。また、（39）は内軸（10）下端に連設したノズルを示
す。この発明の実施例は上記のように構成されており、地
盤改良作業に際し、まずモーター（５）の作動より回転
軸（４）を介して掘削刃体（６）を回転させつつ降下さ
せて、地中に略円柱形状の掘削孔（Ｈ）を穿設するもの
であるが、この際掘削土の排出は行わず、掘削刃体
（６）及び撹拌翼（７）が掘削土中に埋没した状態とす
る。なお、上記の下降掘削作業中、ホッパー（14）に砂な
どの粒粉体（８）を供給し、内軸（10）中に硬化材供給
装置（２）から水を圧入し、回転軸（４）の回転方向を
内軸（10）対し外軸（９）を右回転させて、供給弁（3
8）、外吐出弁（27）及び噴射弁（37）を開、内吐出孔
（32）を閉とすることで噴射弁（37）からバルブケース
（25）中に噴射された水により、同ケース（25）中に供
給弁（38）を介して落下して粒粉体（８）が外吐出弁
（27）を介して外部に吐出され撹拌翼（７）よって掘削
土と混和される。次いで、回転軸（４）を逆回転させながら同軸（４）
を上昇させることにより、供給弁（38）、外吐出弁（2
7）及び噴射弁（37）を閉、内吐出孔（32）を開として
内軸（10）先端のノズル（39）からセメントミルク等の
硬化材を、前記の掘削土と砂の混合土中に注入撹拌す
る。次いで、硬化材の注入を継続しながら回転軸（４）を
下降させて、前工程で注入したセメントミルクと掘削土
との混練を行い、最後に回転軸（４）を引きげつつ仕上
の撹拌を行う。上記のように地盤改良に際し、硬化材の注入に先立っ
て、掘削土中に粒粉体を混入して土質を改善して、しか
るのち硬化材を混入するようにしたので、前記の問題点
を解消することができる。なお、上記地盤改良部分は、硬化材と掘削土及び粒粉
体（８）との混練物の養生期間を経過して効果を発する
ものであり、養生期間中に連続して相互にラップした状
態に多数の地盤改良作業を行うことにより、地盤に広範
囲に連続した地盤改良工事を行うことができ、また一列
に連続して施工することにより地盤中に土止め又は止水
のための地中連続壁体を築造することもできる。特に改良を要する地盤に対し、堀削孔（Ｈ）の堀削
後、硬化材注入に先立って、各地層に対し粒粉体を注入
して混練することにより、同砂等が硬化地盤の骨材とな
り圧力を負担するので強力な地盤改良を行うことができ
る。なお、本発明に用いる粒粉体には砂のほかに、粒状
炉滓、パーライトなどの粒状発泡体等を用いることも可
能である。また、本発明装置によれば、粒粉体だけを地層に混入
撹拌すること、また硬化材のみを混入撹拌することも、
また両者を同時に行うことも可能であり、更に、粒粉体
のかわりに紛状硬化材を土中に注入することができるこ
とから、スラリー状硬化材用の地盤改良装置と、粉状硬
化材用の装置の両方を兼用することができ、従来、二種
の装置を要したものが一台の本発明装置ですむことにな
る。更に、本発明装置での地盤改良に鋼材等とを組合わせ
ることにより、現地土を利用して建造物の支持杭を造成
することができ、捨土の必要がなくなることから特に都
市部において捨土場所、捨土運搬の必要がなくなり、工
事の隘路の一部が解消される。また、粒粉体の土中への吐出口に弁を設けたことで、
粒粉体の吐出を停止しても、掘削土が装置中に逆流する
ことが防止されているため、例えば、粉状固化材を使用
して水底の地盤改良等を行う場合、従来装置では、装置
中に水又は泥土の侵入を防止するために、装置を溝底の
地盤から除去する際も同装置内に圧力をかけておく必要
があり、そのため装置を抜去したときに上記圧力で噴出
した流体により折角改良した地盤の頭部が破壊されると
いう欠点があったが、本発明装置では、圧力をかけずと
も水及び泥土の侵入が防止されるので、流体噴出による
同頭部の破壊がなく、確実な水底地盤の改良が行われる
という利点がある。上記のように、本発明によれば、改良地盤の強度を高
めると共に、同地盤改良の適用範囲を含水比が特に高い
シルト層、又は空隙率が特に高いピート層等の超柔軟地
盤にまで適用範囲を拡大するという効果がある。TECHNICAL FIELD The present invention relates to a ground improvement material injection device. (B) Conventional technology Conventionally, as a method for improving soft ground, a hardening material such as mortar is injected and stirred into excavated soil in an excavation hole formed in the ground, and the ground strength is increased by hardening of the kneaded material. There was a construction method. In addition, in order to improve the soft ground, an excavating blade and a stirring blade are installed at the lower end of the rotary shaft, and in the excavation hole by the blade, hardening of excavating soil and mortar etc. separately injected There was a ground improvement device for improving soft ground with agents. (C) Problems to be solved by the invention However, the ground requiring improvement is often geologically a sedimentary layer, and such a sedimentary layer is composed of a fine-grained silt layer or peat layer, or various types of soil. In many cases, it is composed of alternating layers, for example, when soil improvement is performed using a cement-based hardening material for a ground layer composed of alternating layers of fine-grained sand layers and fine-grained silt layers In addition, since the result of hardening in the silt layer portion is extremely inferior to that in the sand layer portion, a sufficient ground strength cannot be obtained, and therefore, there is a disadvantage that the same strength variation is generated. In order to solve this drawback, an excessive amount of a hardening material is mixed in, but this does not make it possible to sufficiently reduce the ground strength and the variation, and also harden the hardening of the peat layer. It was difficult to get an effect. When mortar obtained by kneading cement and sand with water is poured into the ground and stirred, the mortar has poor fluidity and dispersibility. Takes a long time to complete, the volume of the mixture during the mixing and stirring increases, the mixture overflows to the surface of the ground, the effect of consolidation decreases, the effect of soil improvement is not sufficient, and the overflow further occurs. Excavated soil has to be transported to remove it, which requires extra work.
When the injection of mortar is stopped, there is a drawback that sand and cement are separated in the injection device, which hinders the subsequent work. (D) Means for Solving Problems In the present invention, a rotary shaft having an excavating blade and a stirring blade continuously provided at the tip and a hardening material supply device are provided, and the ground is excavated and excavated by rotation of the rotary shaft. In the soil improvement device configured to mix the excavated soil in the hole and the soil improvement material, the rotary shaft is formed as a double shaft composed of a tubular inner and outer shafts, and a valve case is provided at the lower end of the inner and outer shafts. The valve case has a supply valve that communicates with a space formed between the inner and outer shafts, an outer discharge valve that communicates with the outside, an injection valve that communicates the valve case with the inner shaft, and an inner valve that opens and closes the lower end of the inner shaft. A discharge valve is provided, and each valve is interlocked so that it can be opened / closed by the forward / reverse rotation of the inner and outer shafts.The supply valve, the outer discharge valve, and the injection valve perform the same opening / closing operation, and the inner discharge The valves are configured to perform the on-off valve action opposite to each of these valves. The composed soil improvement material injection device there is provided cents. (E) Action / Effect According to the present invention, when the ground improvement work is performed, by rotating the rotary shaft, the excavating blade body is rotated and hardened to form a substantially cylindrical excavation hole in the ground. Can be drilled. At this time, the excavated soil is not discharged, and the excavated blade and the stirring blade are buried in the excavated soil. Then, during the above-described down excavation work, water is press-fitted into the inner shaft and the outer shaft is rotated with respect to the inner shaft by rotating the rotating shaft with respect to the inner shaft, thereby opening the supply valve, the outer discharge valve, and the injection valve. By operating and closing the inner discharge valve, the water injected from the injection valve into the valve case causes the supply valve to be removed from the space formed between the inner shaft and the outer shaft in the valve case. The granular material such as sand supplied via the external discharge valve can be discharged to the outside, and the granular material can be mixed with the excavated soil by the stirring blade. At this time, the powdery particles can be forcibly and smoothly discharged by the jet water, and the water-mixed powdery particles can be smoothly mixed with the excavated soil by the stirring blades. Then, by rotating the rotating shaft in the reverse direction while raising the rotating shaft, the supply valve, the outer discharge valve, and the injection valve are closed, and the inner discharge valve is opened, so that the cement is applied from the tip of the inner shaft. A hardening material such as milk can be injected into the mixed soil of excavated soil and sand pretreated as described above, and these can be stirred by a stirring blade. Next, while continuing to inject the hardening material, the rotary shaft is lowered, the cement milk injected in the previous step and the excavated soil are kneaded, and finally, the rotary shaft is pulled up and stirring for finishing can be performed. In this way, by mixing and stirring only the granular powder in the excavated soil in the excavation hole, the soil quality is improved prior to the mixing and stirring of the hardening material, and the granular powder is dispersed in the structure of the excavated soil. Since it is carried out promptly and the volume increase of the mixture of the mixing and stirring is suppressed, overflow of the excavated soil to the surface of the ground is suppressed, the waste disposal work becomes unnecessary, and the consolidation effect becomes sufficiently high. As a result, the hardened material is uniformly kneaded in the excavated soil whose soil quality has been improved in advance, and variations in the ground improvement results are eliminated. As described above, mortar obtained by previously kneading cement and sand with water has poor fluidity and dispersibility, and takes a long time to mix. Because of the lack of mortar and the better fluidity and dispersibility compared to mortar, penetration into the excavated soil, that is, mixing, is performed smoothly and in a short time. (F) Embodiments An embodiment of the present invention will be described in detail with reference to the drawings.
Indicates a ground improvement device, and the device (A) is composed of a movable base machine (1) and a hardening material supply device (2). The base machine (1) is rotated by a leader (3) by a rotary shaft (4). ) Is supported vertically, and a shaft (4) is coaxially provided with a rotary shaft (4) by a motor (5) interposed between the leader (3) and the rotary shaft (4), and a drilling blade body ( 6) The stirring shaft (7) and the stirring blade (7) are rotated to lower the coaxial (4) along the leader (3) to form a drilling hole (H) perpendicular to the ground (G). There is. The rotating shaft (4) is composed of a double shaft, that is, a hollow tubular outer shaft (9) and an inner shaft (10) inserted through the outer shaft (9). The inner and outer shafts (10) and (9) are configured to rotate in opposite directions by a double-reversal gear mechanism (11) provided between the upper end and the motor (5). Extends further below the outer shaft (9), and the inner shaft (10) has a drilling blade (6) at the lower end.
Are connected. A stirring blade (7) is arranged above the excavating blade (6), and the stirring blade (7) has large, medium and small stirring blades (7a) (7).
b) (7c), each wing body (7a) (7b) (7
c) is formed in a substantially trapezoidal frame shape when viewed from the side, and a predetermined number is radially arranged around the rotation axis (4). In the small stirring blade (7c), the upper and lower ends of the same blade (7c) are fixed to the lower end of the outer shaft (9), and the medium stirring blade (7b) is larger than the small stirring blade (7c). It is formed in a large substantially trapezoidal frame shape,
The small stirring blade body (7c) is arranged so as to surround the outside, the lower end of the medium stirring blade body (7b) is fixed to the lower end of the inner shaft (10), and the upper end is the small stirring blade body (7c). ) Above the fixed position of the upper end, it is axially supported by the outer shaft (9), and the large stirring blade body (7a) surrounds the outside of the middle stirring blade body (7b), and its upper end is located on the outer shaft (9). ), And the lower end is pivotally supported by the inner shaft (10). Therefore, the large and small stirring blades (7a) (7b)
In the middle of c), they will rotate in the opposite direction. Further, a ground improvement material injection device (B) shown in FIG. 2 is provided at the lower end of the rotating shaft (4), and the device (B) is provided.
Is provided at the upper end of the outer shaft (9) with a hopper (14) (see FIG. 1) communicating with the inside of the hollow tubular outer shaft (9), and the inner shaft (10) below the hopper (14). A screw (15) is continuously provided on the outer peripheral surface of the inner cylinder (16), which is surrounded by a conveying inner cylinder (16) having a diameter smaller than that of the outer shaft (9). The lower end is connected to the inner peripheral surface of the outer shaft (9) via the shaping cylinder (17), the lower end is opened downward, and the opening end edge is obliquely cut. Therefore, the granular powder (8) falling and deposited on the disk (12) described later does not rise above the upper end of the oblique cutout opening end of the lower end of the inner tube (16) for conveyance due to the self-regulating action. Further, as shown in FIGS. 3 and 4, a substantially ring-shaped disc (12) is continuously provided on the outer peripheral surface of the inner shaft (10) below the conveying inner cylinder to form the outer shaft (9). The lower end of the space formed by the inner peripheral surface and the outer peripheral surface of the inner shaft (10) is closed, and a substantially ring-shaped valve disc (13) is attached to the lower surface of the same disc (12) to form the inner shaft (10). And a supply valve (38) that is rotatably provided around the outer shaft (9), and the valve (38) has upper and lower valve holes of the same shape on both discs (12) and (13). (18) (18 ') is drilled, and when both hole positions match, the granular powder (8) deposited on the disc (12) flows out downward, and when they do not match, the granular powder (8) The flow of the body (8) is stopped. Then, in order to rotate the valve disc (13) with respect to the disc (12), a pivot shaft (19) is projectingly provided on the lower surface of the valve disc (13), and the pivot shaft (19) has a substantially V-shape. Of the engaging claw (20) is rotatably pivoted, and the tip (20a) of the claw (20) is urged outward (21) to move the tip (20a) to the outer shaft ( 9) is slidably contacted with the inner peripheral surface of the outer shaft (9), and an engaging projection (22) is provided on the inner peripheral surface of the outer shaft (9) so that the outer shaft ( When 9) rotates counterclockwise, the tip of the engaging claw (20
Even if the engaging projection (22) comes into contact with a), the tip of the claw (20a) escapes inward and allows the projection (22) to pass through. Tip (20a) and outer shaft (9)
The valve disc (13) is rotated rightward through the pawl (20) by engaging with the inner peripheral surface. The valve disc (13) is provided with a substantially arc-shaped elongated hole (23) centered on the inner shaft (10).
The escape pin (24) protruding from the lower surface of the disc (12) is inserted into the valve disc (12) so that the rotation range of the valve disc (13) with respect to the disc (12) can be adjusted to the upper and lower valve holes (18) (18 '). The stroke is limited to opening and closing, and the pin (24) has a long hole (2
At the end position of 3), the side surface of the pin (24) contacts the refraction inner end surface (20b) of the engaging claw (20) and pushes up the tip (20a) of the claw (20), and the tip (20a). And the engaging protrusion (2
2) It is designed to be disengaged from. The engaging claws (20) as described above are symmetrically arranged at both ends of the elongated hole (23). Therefore, when the outer shaft (9) rotates clockwise relative to the inner shaft (10). Upper and lower valve holes (18) (1
8 ') are made to coincide with each other to be in an open state, and are closed at the time of counterclockwise rotation. Even if the outer shaft (9) continues to rotate in one direction, the valve circle is temporarily opened or closed. When the plate (13) rotates, the escape pin (24) in the elongated hole (23) pushes up the tip (20a) of the engaging claw (20), so that the engaging projection (22) passes through and the above-mentioned opening occurs. Alternatively, the closed state is maintained, and the switching of the open / closed state is performed only by the forward / reverse switching of the rotation direction of the outer shaft (9) with respect to the inner shaft (10). A large number of the engaging projections (22) are arranged at equal positions on the inner peripheral surface of the outer shaft (9), and the upper and lower valve holes (18) (18 ') are half-opened due to some reason. Even in the state of (1), since the engaging claw tip (20a) is in the engageable position in the half-opened state, the valve disc is immediately opened or closed by the next engaging projection (22) until a predetermined open or closed state is reached. The open / closed state is reliably maintained by rotating (13). A valve case (25) connected to the inner shaft (10) is provided below the valve disc (13).
5) is a bottomed, substantially cylindrical shape, and the upper edge of the case (25) is
An upper end of a valve cylinder (26) housed rotatably around the inner shaft (10) inside the case (25) is interposed in the middle so as to overlap the lower end of the outer shaft (9). There is. An outer discharge valve (27) is formed between the valve case (25) and the valve cylinder (26), and the valve (27) is provided on the side surface of the valve cylinder (26) and the valve case (25). The inner and outer valve holes (28 ') (28) are provided in a substantially rectangular shape, and when the positions of both valve holes (26a) (25a) match, the valve (27) opens,
When they do not match, the valve (27) is closed,
In order to rotate the valve cylinder (26) with respect to the valve case (25), a pivot shaft (19 ') is provided on the inner surface of the valve cylinder (26) as shown in the developed views of FIGS. 5 and 6. The base end of a substantially triangular engaging claw (20 ') is rotatably pivotally attached to the pivot shaft (19'), and the tip (20'a) of the claw (20 ') is attached to the outside. When the engaging projection (22 ') is provided on the outer surface of the shaft (9) so that the outer shaft (9) rotates leftward with respect to the valve case (25) in FIG. , Tip of engaging claw (20 '
Even if a) contacts the engaging projection (22 '), the tip of the claw (20a)
Escape upward and allow the projection (22 ') to pass therethrough, and in the case of clockwise rotation, the engaging projection (22') engages with the tip of the pawl (20'a) and the valve cylinder (26). Rotate to the right. In addition, a long hole (2
3 ') is bored, and the escape pin (24') protruding from the inner surface of the valve case (25) is inserted into the same long hole (23 ') to insert the valve cylinder into the valve case (25). (26)
Is restricted to a stroke sufficient to open and close the inner and outer valve holes (28 ') (28), and the pin (24') is located at the end position of the elongated hole (23 '). The side surface of ′) comes into contact with the lower end edge (20′b) of the engaging claw (20 ′) and pushes up the tip (20a ′) of the claw (20 ′), and the tip (20 ′).
The engagement between a) and the engaging projection (22 ') is released. The engaging claws (20 ') as described above are symmetrically arranged at both ends of the elongated hole (23). Therefore, when the outer shaft (9) rotates clockwise relative to the inner shaft, the inner and outer valve holes are formed. (28 ') and (28) coincide with each other, the outer discharge valve (27) is opened, and the valve (27) is closed when it is rotated counterclockwise, and the valve cylinder (26) is once opened or closed. If the outer shaft (9) continues to rotate, the escape pin (24 ') in the elongated hole (23')
Pushes up the tip (20'a) of the engaging claw (20 '), the engaging projection (22') passes through, and the above open or closed state is maintained. It is performed only by switching the rotation direction of the outer shaft (9) with respect to 10). In addition, a notch (29) is provided on the side wall of the inner shaft (10) that comes into contact with the inner bottom surface of the valve case (25), and the bottom plate (26a) of the valve cylinder (26) is provided through the notch (29). Part of the inner shaft (1
(0) is extended to the inside of (0), and the extended portion (30) and the closed disc (31) connected to the inner surface of the inner shaft (10) below the extended portion (30) An internal discharge valve (32) is formed between them. In the internal discharge valve (32), the extending portion (30) is formed in a substantially disc shape, and the extending portion (30) and the closed disc (31) are formed in a substantially radial manner in the upper and lower valve holes (33) ( 33 ') is bored, and the internal discharge valve (32) is formed by the rotation of the extension portion integrated with the valve cylinder (26).
I am trying to open and close. As described above, the inner and outer discharge valves (32) (27) operate in conjunction with each other, but in particular, the opening / closing operation of each valve (32) (27) is alternated, that is, the inner discharge valve (32) Each valve hole (28) (2) so that the outer discharge valve (27) is closed when opened and the outer discharge valve (27) is opened when the inner discharge valve (32) is closed.
The positions of 8 '), (33) and (33') are set. In addition, an inner cylinder (34) is provided upright on the upper surface of the extending portion (30) in close proximity to the inner side surface of the inner shaft (10), and between the inner shaft (10) and the inner cylinder (34). The injection valve (37) is configured in the
When the inner discharge valve (32) is closed, 7) is the inner injection hole (35) formed in the side wall of the inner cylinder (34) facing the outer valve hole (28 ') of the valve case (25). The inside of the inner shaft (10) is communicated with the inside of the valve case (25) so as to coincide with the outer injection hole (35 ') formed in the side wall of the shaft (10). In the figure, (36) indicates a hose for injecting a liquid hardening material, and the hose (36) is a hardening material supply device (2).
The liquid hardening material or water is press-fitted into the inner shaft (10) through a swivel (36a) at the end of the hose (36), which communicates with a hardening material pump incorporated therein. Further, (39) shows a nozzle continuously provided at the lower end of the inner shaft (10). The embodiment of the present invention is configured as described above, and at the time of ground improvement work, first, the excavation blade body (6) is rotated and lowered through the rotation shaft (4) by the operation of the motor (5), The excavation hole (H) having a substantially cylindrical shape is bored in the ground, but at this time, the excavated soil is not discharged, and the excavation blade body (6) and the stirring blade (7) are buried in the excavated soil. State. During the down excavation work described above, granular powder (8) such as sand is supplied to the hopper (14), water is press-fitted from the hardening material supply device (2) into the inner shaft (10), and the rotary shaft ( 4) Rotate the inner shaft (10) to the outer shaft (9) clockwise to rotate the supply valve (3).
8), the outer discharge valve (27) and the injection valve (37) are opened, and the inner discharge hole (32) is closed, so that the water is injected from the injection valve (37) into the valve case (25). The granular powder (8) drops into the case (25) through the supply valve (38) and is discharged to the outside through the outer discharge valve (27), and is mixed with the excavated soil by the stirring blade (7). Then, while rotating the rotating shaft (4) in the reverse direction, the coaxial (4)
By raising the supply valve (38), the outer discharge valve (2
7) and the injection valve (37) are closed, the inner discharge hole (32) is opened, and a hardening material such as cement milk is introduced from the nozzle (39) at the tip of the inner shaft (10) in the mixed soil of the excavated soil and sand. Inject and stir. Next, the rotary shaft (4) is lowered while continuing the injection of the hardening material to knead the cement milk injected in the previous step and the excavated soil, and finally, the rotary shaft (4) is pulled while stirring the finish. I do. As described above, when improving the ground, prior to the injection of the hardening material, the granular powder was mixed into the excavated soil to improve the soil quality, and after that, the hardening material was mixed. It can be resolved. The above-mentioned ground improvement portion is effective after the curing period of the kneaded material of the hardened material, the excavated soil and the granular powder (8), and is continuously wrapped with each other during the curing period. A large number of ground improvement works can be performed on the ground, and ground improvement work can be performed on the ground over a wide area. Walls can also be built. Especially for the ground that needs improvement, after the excavation of the drilling hole (H) and before the hardening material is injected, granular powder is injected into each layer and kneaded, so that the same sand etc. hardens the bone of the ground. Since it becomes a material and bears the pressure, strong ground improvement can be performed. The granular powder used in the present invention may be granular furnace slag, granular foam such as pearlite, or the like, in addition to sand. According to the apparatus of the present invention, it is also possible to mix and agitate only the granular powder into the formation, and to mix and agitate only the hardening material,
It is also possible to do both at the same time, and since a powdery hardener instead of granular powder can be injected into the soil, a ground improvement device for slurry hardener and a powdery hardener for powdery hardener The device of the present invention can be used as both of the above-mentioned devices, and conventionally, only one device of the present invention requires two kinds of devices. Furthermore, by combining with steel materials etc. for ground improvement with the device of the present invention, it is possible to construct a support pile for a building using the local soil, and there is no need to dispose of soil. There is no need to transport soil and waste, and part of the bottleneck for construction will be eliminated. In addition, by providing a valve at the outlet of the granular powder into the soil,
Even if the discharge of the granular powder is stopped, since the excavated soil is prevented from flowing back into the device, for example, when using a powdered solidifying material to improve the ground of the water bottom, in the conventional device, In order to prevent water or mud from entering the device, it is necessary to apply pressure to the device even when removing it from the ground at the bottom of the ditch, so when the device was removed, it was ejected at the above pressure. Although there is a drawback that the head of the ground improved by the fluid is destroyed by the fluid, in the device of the present invention, the invasion of water and mud is prevented without applying pressure, so that the head of the same is destroyed by the jet of the fluid. However, there is an advantage that a reliable improvement of the submarine ground is performed. As described above, according to the present invention, while improving the strength of the improved ground, the applicable range of the ground improvement is applied to a super soft ground such as a silt layer having a particularly high water content or a peat layer having a particularly high porosity. This has the effect of expanding the range.

【図面の簡単な説明】第１図は、本発明による地盤改良材注入装置を有する地
盤改良装置の全体側面図。第２図は、本発明の要部を示す縦断面図。第３図は、第２図Ｉ−Ｉ断面図（供給弁及び外吐出弁
閉）第４図は、第２図Ｉ−Ｉ断面図（供給弁及び外吐出弁
開）第５図は、第３図III−III断面展開図（外吐出弁閉）第６図は、第４図IV−IV断面展開図（外吐出弁開）第７図は、第２図II−II断面図（内吐出弁開）第８図は、第２図II−II断面図（内吐出弁閉）（Ａ）：地盤改良装置（Ｇ）：地盤（Ｈ）：掘削孔（２）：硬化材供給装置（４）：回転軸（６）：掘削刃体（９）：外軸（10）：内軸（27）：外吐出弁（32）：内吐出弁BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall side view of a ground improvement device having a ground improvement material injection device according to the present invention. FIG. 2 is a vertical cross-sectional view showing the main part of the present invention. FIG. 3 is a sectional view taken along line I-I of FIG. 2 (closes the supply valve and the outer discharge valve). FIG. 4 is a sectional view taken along line I-I of FIG. 2 (opened the supply valve and the outer discharge valve). Fig. 3 III-III cross-section development view (outer discharge valve closed) Fig. 4 Fig. 4 IV-IV cross-section development view (outer discharge valve open) Fig. 7 Fig. 2 II-II cross-section view (inner discharge) FIG. 8 is a sectional view taken along line II-II of FIG. 2 (inner discharge valve is closed) (A): Ground improvement device (G): Ground (H): Excavation hole (2): Hardener supply device (4) ): Rotating shaft (6): Excavator blade (9): Outer shaft (10): Inner shaft (27): Outer discharge valve (32): Inner discharge valve

Claims

(57) [Claims] It is equipped with a rotating shaft (4) in which a drilling blade (6) and a stirring blade (7) are connected to the tip and a hardening material supply device (2), and the ground (G) is rotated by the rotation of the rotating shaft (4). In a soil improvement device (A) configured to mix excavation and excavated soil in an excavation hole (H) with a soil improvement material, a rotary shaft (4) is composed of tubular inner and outer shafts (10) and (9), respectively. A valve case (25) is provided at the lower end of the inner and outer shafts (10) and (9), and the valve case (25) communicates with the space formed between the inner and outer shafts (10) and (9). A supply valve (38), an outer discharge valve (27) communicating with the outside, an injection valve (37) communicating the valve case (25) with the inner shaft (9),
An inner discharge valve (32) for opening and closing the lower end of the inner shaft (9) is provided, and each valve (38) (27) (37) (32) is connected to the inner and outer shaft (10).
(9) is connected in an interlocking manner so that it can be opened and closed by reversing the relative rotation direction of (9), and the supply valve (38), the outer discharge valve (27) and the injection valve (37) perform the same on-off valve operation and The soil improvement material injection device in which the discharge valve (32) is configured to perform an on-off valve operation opposite to those of these valves (38) (27) (37).