JPH08128034A

JPH08128034A - Small type soil improving device and soil improving construction method and boring rod

Info

Publication number: JPH08128034A
Application number: JP15260594A
Authority: JP
Inventors: Masanao Wada; 昌尚和田
Original assignee: TSUKUSHI KOGYO KK
Current assignee: TSUKUSHI KOGYO KK
Priority date: 1994-06-10
Filing date: 1994-06-10
Publication date: 1996-05-21

Abstract

PURPOSE: To make construction possible in a narrow construction site where a large type crawler transporter can not change its course or a construction site having a narrow alley and a narrow turning of road which must be passed through. CONSTITUTION: An elevating base 11 to elevate along a guide 10 is provided on a short leader 2 provided on a small type crawler which can travel and change its course even in a narrow area. A rod chuck 13 rotatively driven by a motor 9 is provided on the elevating base 11. An telescopic boring rod 14 whose upper end is attached to the rod chuck 13 by chucking is set along the leader 2. The boring rod 14 is composed of at least two short connected steel pipes which are different in diameter and telescopically fitted inside and outside. An excavating blade 15, an agitating blade 16 and a discharging hole for ground hardening material are provided on the circumference of the tip of the most outside connected steel pipe. A locking mechanism 21 which mutually stretches out the inner and outer connected steel pipes 14a, 14b and connectedly locks their ends is provided in the upper end part of the outside connected steel pipe.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】この発明は、大型のクローラーが
方向転換できないような狭い施工現場や、狭い路地や狭
い曲がり角などを通る必要のある施工現場において施工
可能なように小型化された地盤改良装置に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement which is small in size so that it can be installed in a narrow construction site where a large crawler cannot turn, or in a construction site that needs to pass through a narrow alley or a narrow corner. It relates to the device.

【０００２】[0002]

【従来の技術】従来、大型のクローラーに長さが 10m以
上もの長尺なリーダーを取付けて、このリーダーに沿っ
てリーダーと同程度に長尺なボーリングロッドを昇降回
転駆動機により昇降回転自在取付け、このボーリングロ
ッドを回転しながら地盤中に貫入して地盤を削孔した
後、ボーリングロッド内に圧送した地盤硬化材を吐出孔
から削孔土砂中に噴射すると共に、このロッドを回転し
ながら引き上げてその外周に設けた攪拌羽根により削孔
内の土砂と地盤硬化材を攪拌し、地中に凝結土柱を造成
して地盤を改良するようにした大型の地盤改良装置が用
いられている。2. Description of the Related Art Conventionally, a long leader with a length of 10 m or more is attached to a large crawler, and a boring rod that is as long as the leader is attached along this leader by a raising and lowering rotation drive machine so that it can be freely rotated up and down. After rotating the boring rod to penetrate into the ground to drill the ground, the ground hardening material pumped into the boring rod is injected from the discharge hole into the drilling earth and sand, and the rod is pulled up while rotating. A large ground improvement device is used to improve the ground by agitating the sand and sand in the drilled hole and the hardened ground material by a stirring blade provided on the outer periphery of the ground to form a solidified soil column in the ground.

【０００３】[0003]

【発明が解決しようとする課題】上記従来の大型の地盤
改良装置では、クローラーが大型でそのリーダー及びボ
ーリングロッドが長大であるため、これを施工現場に搬
入するのに狭い路地や狭い曲がり角を通る必要がある場
合やクローラーが方向転換できないような狭い施工現場
には、搬入ができず、施工も不可能となる。In the above-mentioned conventional large-scale ground improvement device, the crawler is large and the leader and the boring rod are long, so that it can pass through a narrow alley or a narrow turn to carry it to the construction site. If it is necessary or if the crawler cannot be turned around, it will not be possible to carry it into a narrow construction site and construction will be impossible.

【０００４】このような狭小地の現場は都市に多く見ら
れ、一般的なショベルカーやロードローラーなどの土木
作業機械には狭小現場用に小型化されたものが使用され
ているが、地盤改良機においては小型化されたものはな
く、地盤改良を伴う都市開発の障害となっているのが現
状である。Sites of such narrow land are often found in cities, and civil engineering machines such as general excavators and road rollers, which are miniaturized for narrow sites, are used. There is no downsized machine, which is an obstacle to urban development accompanied by ground improvement.

【０００５】[0005]

【課題を解決するための手段】この発明は前記従来の課
題を解決するために、狭小地においても走行及び方向転
換可能な小型のクローラー１に設けた短尺なリーダー２
に、ガイド１０に沿って昇降する昇降台１１が設けら
れ、昇降台１１にはモーター９により回転駆動するロッ
ドチャック１３が設けられ、リーダー２には上端をロッ
ドチャック１３にチャッキングして取付けた伸縮式ボー
リングロッド１４がセットされ、このボーリングロッド
は少なくとも２本の径の異なる短尺な連結鋼管１４ａ，
１４ｂをテレスコピック式に内外に嵌め合わしてなり、
最外側の連結鋼管１４ａにはその先端部周囲に掘削羽根
１５及び攪拌羽根１６ならびに地盤硬化材の吐出孔が設
けられ、外側の連結鋼管１４ａの上端部には、内外の連
結鋼管１４ａ，１４ｂを相互に引き延ばして端部を連結
ロックするためのロック機構２１が設けられている小型
地盤改良装置を提案するものである。In order to solve the above-mentioned conventional problems, the present invention provides a short leader 2 provided on a small crawler 1 capable of traveling and changing direction even in a narrow area.
Is provided with an elevating table 11 that moves up and down along a guide 10. The elevating table 11 is provided with a rod chuck 13 that is driven to rotate by a motor 9, and the leader 2 is attached by chucking the upper end of the rod chuck 13. The telescopic boring rod 14 is set, and the boring rod has at least two short connecting steel pipes 14a having different diameters,
14b is telescopically fitted inside and outside,
The outermost connecting steel pipe 14a is provided with an excavating blade 15, a stirring blade 16 and a discharge hole for the ground hardening material around the tip portion thereof, and the outer connecting steel pipe 14a has inner and outer connecting steel pipes 14a, 14b at the upper end thereof. The present invention proposes a small ground improvement device provided with a lock mechanism 21 for mutually extending and connecting and locking the ends.

【０００６】この発明は、狭小地においても走行及び方
向転換可能な小型のクローラー１に設けた短尺なリーダ
ー２に、ガイド１０に沿って昇降する昇降台１１が設け
られ、昇降台１１にはモーター９により回転駆動するロ
ッドチャック１３が設けられ、リーダー２には上端をロ
ッドチャック１３にチャッキングして取付けた伸縮式ボ
ーリングロッド１４がセットされ、このボーリングロッ
ド１４は少なくとも２本の径の異なる短尺な連結鋼管１
４ａ，１４ｂをテレスコピック式に内外に嵌め合わして
なり、最外側の連結鋼管１４ａにはその先端部周囲に掘
削羽根１５及び攪拌羽根１６ならびに地盤硬化材の吐出
孔１７が設けられ、外側の連結鋼管１４ａの上端部には
内周側に張り出した係止段部１８が、また内側の連結鋼
管１４ｂにはその下端部に外側に張り出した係止段部１
９が設けられ、外側の連結鋼管１４ａの上端部には、内
外の連結鋼管１４ａ，１４ｂを相互に引き延ばして端部
を連結ロックするためのロック機構２１が設けられ、こ
のロック機構２１は、外側の連結鋼管１４ａの内周円に
接する接線Ｓを中心とした円筒状をなし、その内径が内
側の連結鋼管１４ｂの係止段部１９の肉厚寸法よりも小
さく形成された円筒部２２と、この円筒部２２内に回転
自在に挿嵌され、その円周の中間部に連結鋼管の内周面
の軌跡に沿って円弧状に切り取った円弧凹部２３を有す
るロックピン２４とからなり、内側の連結鋼管１４ｂの
下端の係止段部１９の外周には、内外の連結鋼管１４
ａ，１４ｂを相互に引き延ばして相互の係止段部１８，
１９同士を突き当てた状態において、円筒部２２の内周
面の軌跡に沿って切り取った円弧状凹部２９が設けられ
ている小型地盤改良装置を提案するものである。According to the present invention, a small leader 2 provided on a small crawler 1 capable of traveling and changing direction even in a narrow land is provided with a lift base 11 that moves up and down along a guide 10. The lift base 11 has a motor. 9 is provided with a rod chuck 13 which is rotationally driven, and a telescopic boring rod 14 whose upper end is chucked and attached to the rod chuck 13 is set in the leader 2. This boring rod 14 has at least two short lengths with different diameters. Na connected steel pipe 1
4a and 14b are telescopically fitted to each other inside and outside, and the outermost connecting steel pipe 14a is provided with an excavation blade 15, a stirring blade 16 and a ground hardening material discharge hole 17 around the tip end portion thereof, and an outer connecting steel pipe. An engaging step portion 18 projecting toward the inner peripheral side is provided at an upper end portion of 14a, and an engaging step portion 1 projecting outward at a lower end portion of the inner connecting steel pipe 14b.
9, a lock mechanism 21 is provided at the upper end of the outer connecting steel pipe 14a for extending the inner and outer connecting steel pipes 14a, 14b to connect and lock the ends. A cylindrical portion 22 having a cylindrical shape centered on a tangent line S contacting the inner circumferential circle of the connecting steel pipe 14a, the inner diameter of which is smaller than the wall thickness of the locking step portion 19 of the inner connecting steel pipe 14b; A lock pin 24 is rotatably inserted into the cylindrical portion 22 and has an arcuate concave portion 23 cut in an arc shape along the locus of the inner peripheral surface of the connecting steel pipe at an intermediate portion of its circumference. On the outer periphery of the locking step portion 19 at the lower end of the connecting steel pipe 14b, the inner and outer connecting steel pipes 14 are provided.
a and 14b are extended to each other so that mutual locking step portions 18,
The present invention proposes a small ground improvement apparatus having arcuate concave portions 29 cut along the locus of the inner peripheral surface of the cylindrical portion 22 in a state where 19 are abutted against each other.

【０００７】この発明は、狭小地においても走行及び方
向転換可能な小型のクローラー１に設けた短尺なリーダ
ー２に、ガイド１０に沿って昇降する昇降台１１が設け
られ、昇降台１１にはモーター９により回転駆動するロ
ッドチャック１３が設けられ、リーダー２には上端をロ
ッドチャック１３にチャッキングして取付けた伸縮式ボ
ーリングロッド１４がセットされ、このボーリングロッ
ド１４は少なくとも２本の径の異なる短尺な連結鋼管１
４ａ，１４ｂをテレスコピック式に内外に嵌め合わして
なり、最外側の連結鋼管１４ａにはその先端部周囲に掘
削羽根１５及び攪拌羽根１６ならびに地盤硬化材の吐出
孔１７が設けられ、外側の連結鋼管１４ａの上端部には
内周側に張り出した係止段部１８が、また内側の連結鋼
管１４ｂにはその下端部に外側に張り出した係止段部１
９が設けられ、各係止段部１８，１９にはシール材２０
が設けられ、外側の連結鋼管１４ａの上端部には、内外
の連結鋼管１４ａ，１４ｂを相互に引き延ばして端部を
連結ロックするためのロック機構２１が設けられ、この
ロック機構２１は、外側の連結鋼管１４ａの内周円に接
する接線Ｓを中心とした円筒状をなし、その内径が内側
の連結鋼管１４ｂの係止段部１９の肉厚寸法よりも小さ
く形成された円筒部２２と、この円筒部２２内に回転自
在に挿嵌され、その円周の中間部に連結鋼管１４ａの内
周面の軌跡に沿って円弧状に切り取った円弧凹部２３を
有するロックピン２４とからなり、円筒部２２の両端部
に摺接するロックピン１４の両端部にはシール材２８が
装着され、内側の連結鋼管１４ｂの下端の係止段部１９
の外周には、内外の連結鋼管１４ａ，１４ｂを相互に引
き延ばして相互の係止段部１８，１９同士を突き当てた
状態において、円筒部２２の内周面の軌跡に沿って切り
取った円弧状凹部２３が設けられている小型地盤改良装
置を提案するものである。According to the present invention, a short leader 2 provided on a small crawler 1 capable of traveling and changing direction even in a narrow land is provided with a lift base 11 that moves up and down along a guide 10, and the lift base 11 has a motor. 9 is provided with a rod chuck 13 which is rotationally driven, and a telescopic boring rod 14 whose upper end is chucked and attached to the rod chuck 13 is set in the leader 2. This boring rod 14 has at least two short lengths with different diameters. Na connected steel pipe 1
4a and 14b are telescopically fitted to each other inside and outside, and the outermost connecting steel pipe 14a is provided with an excavation blade 15, a stirring blade 16 and a ground hardening material discharge hole 17 around the tip end portion thereof, and an outer connecting steel pipe. An engaging step portion 18 projecting toward the inner peripheral side is provided at an upper end portion of 14a, and an engaging step portion 1 projecting outward at a lower end portion of the inner connecting steel pipe 14b.
9 is provided, and a sealing material 20 is provided on each locking step portion 18, 19.
Is provided at the upper end of the outer connecting steel pipe 14a, and a lock mechanism 21 is provided for extending the inner and outer connecting steel pipes 14a and 14b to lock the ends thereof. A cylindrical portion 22 having a cylindrical shape centered on a tangent line S contacting the inner circumference of the connecting steel pipe 14a and having an inner diameter smaller than the wall thickness dimension of the locking step portion 19 of the inner connecting steel pipe 14b. A lock pin 24 which is rotatably inserted into the cylindrical portion 22 and has an arcuate concave portion 23 cut in an arc shape along the locus of the inner peripheral surface of the connecting steel pipe 14a at an intermediate portion of its circumference. Sealing materials 28 are attached to both ends of the lock pin 14 which are in sliding contact with both ends of the locking pin 22 and the locking step 19 at the lower end of the inner connecting steel pipe 14b.
The inner and outer connecting steel pipes 14a and 14b are extended to each other and the locking step portions 18 and 19 are abutted to each other on the outer periphery of the circular arc shape cut along the locus of the inner peripheral surface of the cylindrical portion 22. It proposes a small ground improvement device provided with a recess 23.

【０００８】この発明は、少なくとも２本の径の異なる
短尺な連結鋼管１４ａ，１４ｂをテレスコピック式に内
外に嵌め合わしてなり、最外側の連結鋼管１４ａにはそ
の先端部周囲に掘削羽根１５及び攪拌羽根１６ならびに
地盤硬化材の吐出孔１７が設けられ、外側の連結鋼管１
４ｂの上端部には、内外の連結鋼管１４ａ，１４ｂを相
互に引き延ばして端部を連結ロックするためのロック機
構２１が設けられた伸縮式ボーリングロッド１４を、狭
小地においても走行及び方向転換可能な小型のクローラ
ー１に設けた短尺なリーダー２にセットし、その上端を
リーダー２に沿って昇降自在に設けた昇降台１１にモー
ター９により回転駆動可能に設けたロッドチャック１３
にチャッキングして取付け、このボーリングロッド１４
をモーター９により回転しながら昇降台１１により加圧
してリーダー２に沿って下降させ、先端の掘削羽根１５
により限界掘削長まで掘削した後、内側の連結鋼管１４
ｂを引き出してその上端をロッドチャック１３にチャッ
キングし、昇降台１１を上昇させて連結鋼管１４ｂを引
き出し限界まで伸長させ、ロック機構２１により連結鋼
管１４ａ，１４ｂ相互を連結ロックし、次に引き延ばし
て連結ロックされた連結鋼管１４ａ，１４ｂをモーター
９で回転させながら昇降台１１を再び下降させ、先端の
掘削羽根１５により限界掘削長まで掘削した後、ボーリ
ングロッド１４内にセメントミルク等の地盤硬化材を圧
送して吐出孔１７から周辺の掘削土砂中に注入すると共
に、ボーリングロッド１４を回転しながら引き上げて攪
拌羽根１６により土砂を地盤硬化材と共に均一に攪拌
し、昇降台１１が上限に到達するまで引き延ばされたボ
ーリングロッド１４を引き上げた後、前記ロック機構２
１による内外の連結ロッド１４ａ，１４ｂの連結ロック
を解除して内側の連結ロッド１４ｂを下降させて外側の
連結ロッド１４ａ内に挿嵌して収縮し、その後は外側の
連結ロッド１４ａの上端をロッドチャック１３にチャッ
キングし、これを回転しながら引き上げて上記同様に注
入した地盤硬化材と共に土砂を攪拌羽根により均一に攪
拌し、ボーリングロッドを引き上げた削孔内の土砂を凝
固させて地中造成杭を構築する地盤改良工法を提案する
ものである。According to the present invention, at least two short connecting steel pipes 14a and 14b having different diameters are telescopically fitted to each other inside and outside, and the outermost connecting steel pipe 14a has a drilling blade 15 and a stirring member around its tip. The blade 16 and the ground hardening material discharge hole 17 are provided, and the outer connecting steel pipe 1 is provided.
The telescopic boring rod 14 provided with a lock mechanism 21 for connecting and locking the ends of the inner and outer connecting steel pipes 14a and 14b to each other at the upper end of the 4b is capable of traveling and changing direction even in a narrow area. Set on a short leader 2 provided on a small crawler 1, and a rod chuck 13 that is rotatably driven by a motor 9 on an elevating table 11 whose upper end is vertically movable along the leader 2.
Attached by chucking to this boring rod 14
While being rotated by the motor 9, it is pressurized by the lifting platform 11 and moved down along the leader 2, and the excavation blade 15 at the tip is moved.
After excavating to the limit excavation length by
b is pulled out and the upper end thereof is chucked by the rod chuck 13, the elevating table 11 is raised to extend the connecting steel pipe 14b to the pulling limit, the connecting steel pipes 14a and 14b are connected and locked by the lock mechanism 21, and then extended. While rotating the connected steel pipes 14a and 14b that are locked together by the motor 9, the elevating table 11 is lowered again, and after excavating to the limit excavation length by the excavation blade 15 at the tip, the ground hardening such as cement milk in the boring rod 14 is performed. The material is pumped and injected into the surrounding excavated earth and sand from the discharge hole 17, and the boring rod 14 is rotated and pulled up to evenly agitate the earth and sand with the ground hardening material by the agitating blade 16, and the lifting platform 11 reaches the upper limit. After pulling up the extended boring rod 14 until
The connection lock of the inner and outer connecting rods 14a and 14b is released by 1 and the inner connecting rod 14b is lowered to be inserted into the outer connecting rod 14a to be contracted, and thereafter the upper end of the outer connecting rod 14a is set to the rod. The chuck 13 is chucked and pulled up while rotating, and the soil and sand together with the ground hardening material injected in the same manner as above are uniformly agitated by a stirring blade, and the earth and sand in the drilled hole where the boring rod is pulled up is solidified to form an underground soil. We propose a ground improvement method for constructing piles.

【０００９】この発明は、少なくとも２本の径の異なる
短尺な連結鋼管１４ａ，１４ｂをテレスコピック式に内
外に嵌め合わしてなり、最外側の連結鋼管１４ａにはそ
の先端部周囲に掘削羽根１５及び攪拌羽根１６ならびに
地盤硬化材の吐出孔１７が設けられ、外側の連結鋼管１
４ａの上端部には内周側に張り出した係止段部１８が、
また内側の連結鋼管１４ｂにはその下端部に外側に張り
出した係止段部１９が設けられ、外側の連結鋼管１４ａ
の上端部には、内外の連結鋼管１４ａ，１４ｂを相互に
引き延ばして端部を連結ロックするためのロック機構２
１が設けられ、このロック機構２１は、外側の連結鋼管
１４ａの内周円に接する接線Ｓを中心とした円筒状をな
し、その内径が内側の連結鋼管１４ｂの係止段部１９の
肉厚寸法よりも小さく形成された円筒部２２と、この円
筒部２２内に回転自在に挿嵌され、その円周の中間部に
連結鋼管の内周面の軌跡に沿って円弧状に切り取った円
弧凹部２３を有するロックピン２４とからなり、内側の
連結鋼管１４ｂの下端の係止段部１９の外周には、内外
の連結鋼管１４ａ，１４ｂを相互に引き延ばして相互の
係止段部１８，１９同士を突き当てた状態において、円
筒部２２の内周面の軌跡に沿って切り取った円弧状凹部
２３が設けられている伸縮式ボーリングロッド１４を、
狭小地においても走行及び方向転換可能な小型のクロー
ラー１に設けた短尺なリーダー２にセットし、その上端
を前記リーダー２に沿って昇降自在に設けた昇降台１１
にモーターにより回転駆動可能に設けたロッドチャック
１３にチャッキングして取付け、ボーリングロッド１４
をモーター９により回転しながら昇降台１１により加圧
してリーダー２に沿って下降させ、先端の掘削羽根１５
により限界掘削長まで掘削した後、内側の連結鋼管１４
ｂを引き出してその上端をロッドチャック１３にチャッ
キングし、昇降台１１を上昇させて連結鋼管１４ｂを引
き出し限界まで伸長させ、相互の係止段部１８，１９同
士をつき当てた状態において、ロックピン２４を約半回
転することにより、その円弧状凹部２３の無い外周部を
内側の連結鋼管１４ｂの係止段部１９の円弧状凹部２９
に食い込ませて連結鋼管１４ａ，１４ｂ相互を連結ロッ
クし、次に引き延ばして連結ロックされた連結鋼管１４
ａ，１４ｂをモーター９で回転させながら昇降台１１を
再び下降させ、先端の掘削羽根１５により限界掘削長ま
で掘削した後、ボーリングロッド１４内にセメントミル
ク等の地盤硬化材を圧送して吐出孔１７から周辺の掘削
土砂中に注入すると共に、ボーリングロッドを回転しな
がら引き上げて攪拌羽根１６により土砂を地盤硬化材と
共に均一に攪拌し、昇降台１１が上限に到達するまで引
き延ばされたボーリングロッド１４を引き上げた後、ロ
ックピン２４をその円弧状部２３が外側の連結鋼管１４
ａの内周面に沿った位置にくるように回転し、この状態
で内側の連結ロッド１４ｂを下降させて外側の連結ロッ
ド１４ａ内に挿嵌して収縮し、その後は外側の連結ロッ
ド１４ａの上端をロッドチャック１３にチャッキング
し、これを回転しながら引き上げて上記同様に注入した
地盤硬化材と共に土砂を攪拌羽根により均一に攪拌し、
ボーリングロッド１４を引き上げた削孔内の土砂を凝固
させて地中造成杭を構築する地盤改良工法を提案するも
のである。According to the present invention, at least two short connecting steel pipes 14a and 14b having different diameters are telescopically fitted to each other inside and outside, and the outermost connecting steel pipe 14a has a drilling blade 15 and a stirring member around its tip. The blade 16 and the ground hardening material discharge hole 17 are provided, and the outer connecting steel pipe 1 is provided.
At the upper end of 4a, there is a locking step portion 18 protruding to the inner peripheral side,
Further, the inner connecting steel pipe 14b is provided with a locking step portion 19 projecting outward at the lower end thereof, and the outer connecting steel pipe 14a is provided.
A locking mechanism 2 for extending the inner and outer connecting steel pipes 14a, 14b to each other and connecting and locking the ends at the upper end of the
1, the lock mechanism 21 has a cylindrical shape centered on a tangent line S that is in contact with the inner circumference circle of the outer connecting steel pipe 14a, and the inner diameter thereof is the wall thickness of the locking step portion 19 of the inner connecting steel pipe 14b. A cylindrical portion 22 formed to be smaller than the size, and an arc-shaped concave portion that is rotatably inserted in the cylindrical portion 22 and is cut in an arc shape along the locus of the inner peripheral surface of the connecting steel pipe in the middle portion of the circumference. And a locking pin 24 having 23, the inner and outer connecting steel pipes 14a and 14b are extended to each other on the outer periphery of the engaging step portion 19 at the lower end of the inner connecting steel pipe 14b. The telescopic boring rod 14 provided with an arcuate concave portion 23 cut along the locus of the inner peripheral surface of the cylindrical portion 22,
An elevating table 11 which is set on a short leader 2 provided on a small crawler 1 capable of traveling and changing direction even in a narrow land, and the upper end of which is vertically movable along the leader 2.
Attached to the rod chuck 13 which is rotatably driven by a motor on the boring rod 14
While being rotated by the motor 9, it is pressurized by the lifting platform 11 and moved down along the leader 2, and the excavation blade 15 at the tip is moved.
After excavating to the limit excavation length by
b is pulled out and the upper end thereof is chucked by the rod chuck 13, the elevating table 11 is raised to extend the connecting steel pipe 14b to the pulling limit, and the locking step portions 18, 19 are abutted against each other and locked. By rotating the pin 24 about a half turn, the outer peripheral portion without the arcuate recess 23 is moved to the arcuate recess 29 of the locking step 19 of the inner connecting steel pipe 14b.
The connecting steel pipes 14a and 14b are connected and locked by being bitten into
While rotating a and 14b by the motor 9, the elevating table 11 is lowered again, and after excavating to the limit excavation length by the excavating blade 15 at the tip, the ground hardening material such as cement milk is pressure-fed into the boring rod 14 to discharge holes. Injecting into the surrounding excavated sediment from 17 and rotating the boring rod while pulling it up, the stirring blade 16 uniformly stirs the soil together with the ground hardening material, and the boring extended until the lift 11 reaches the upper limit. After pulling up the rod 14, the lock pin 24 is connected to the connecting steel pipe 14 whose arcuate portion 23 is on the outside.
It rotates so as to come to a position along the inner peripheral surface of a, and in this state, the inner connecting rod 14b is lowered to be inserted into the outer connecting rod 14a and contracted, and thereafter, the outer connecting rod 14a The upper end is chucked to the rod chuck 13, and the rod chuck 13 is rotated and pulled up to uniformly stir the soil and sand together with the ground hardening material injected in the same manner as above with a stirring blade,
This is to propose a ground improvement method for solidifying earth and sand in the drilled hole where the boring rod 14 is pulled up to construct an underground pile.

【００１０】この発明は、少なくとも２本の径の異なる
短尺な連結鋼管１４ａ，１４ｂをテレスコピック式に内
外に嵌め合わしてなり、最外側の連結鋼管１４ａにはそ
の先端部周囲に掘削羽根１５及び攪拌羽根１６ならびに
地盤硬化材の吐出孔１７が設けられ、外側の連結鋼管１
４ａの上端部には内周側に張り出した係止段部１８が、
また内側の連結鋼管１４ｂにはその下端部に外側に張り
出した係止段部１９が設けられ、外側の連結鋼管１４ａ
の上端部には、内外の連結鋼管１４ａ，１４ｂを相互に
引き延ばして端部を連結ロックするためのロック機構２
１が設けられ、このロック機構２１は、外側の連結鋼管
１４ａの内周円に接する接線Ｓを中心とした円筒状をな
し、その内径が内側の連結鋼管１４ｂの係止段部１９の
肉厚寸法よりも小さく形成された円筒部２２と、この円
筒部２２内に回転自在に挿嵌され、その円周の中間部に
連結鋼管１４ａの内周面の軌跡に沿って円弧状に切り取
った円弧凹部２３を有するロックピン２４とからなり、
内側の連結鋼管１４ｂの下端の係止段部１９の外周に
は、内外の連結鋼管１４ａ，１４ｂを相互に引き延ばし
て相互の係止段部１８，１９同士を突き当てた状態にお
いて、円筒部２２の内周面の軌跡に沿って切り取った円
弧状凹部２９が設けられているボーリングロッドを提案
するものである。According to the present invention, at least two short connecting steel pipes 14a and 14b having different diameters are telescopically fitted to each other inside and outside, and the outermost connecting steel pipe 14a has a drilling blade 15 and a stirring member around its tip. The blade 16 and the ground hardening material discharge hole 17 are provided, and the outer connecting steel pipe 1 is provided.
At the upper end of 4a, there is a locking step portion 18 protruding to the inner peripheral side,
Further, the inner connecting steel pipe 14b is provided with a locking step portion 19 projecting outward at the lower end thereof, and the outer connecting steel pipe 14a is provided.
A locking mechanism 2 for extending the inner and outer connecting steel pipes 14a, 14b to each other and connecting and locking the ends at the upper end of the
1, the lock mechanism 21 has a cylindrical shape centered on a tangent line S that is in contact with the inner circumference circle of the outer connecting steel pipe 14a, and the inner diameter thereof is the wall thickness of the locking step portion 19 of the inner connecting steel pipe 14b. A cylindrical portion 22 formed to be smaller than the dimension, and an arc which is rotatably inserted in the cylindrical portion 22 and is cut in an arc shape along the locus of the inner peripheral surface of the connecting steel pipe 14a at the middle portion of the circumference thereof. A lock pin 24 having a recess 23,
In the state where the inner and outer connecting steel pipes 14a and 14b are extended to each other and the mutual engaging step portions 18 and 19 are butted against each other, the cylindrical portion 22 is provided around the outer periphery of the engaging step portion 19 at the lower end of the inner connecting steel pipe 14b. The present invention proposes a boring rod provided with an arcuate concave portion 29 cut along the locus of the inner peripheral surface.

【００１１】[0011]

【作用】短尺なリーダー２を設けた小型のクローラー１
を用いるため、狭小地の現場あるいは狭小地を通る現場
においてもクローラー１を搬入することができ、またボ
ーリングロッド１４は短尺な連結鋼管１４ａ，１４ｂを
テレスコピック式に内外に嵌め合わして伸縮自在である
ため、短尺なリーダーにセットすることができ、掘進時
には段階的に伸長して十分な深度の削孔を行うことがで
き、またボーリングロッド１４の引き上げ時には段階的
に収縮して引き上げることができる。[Operation] Small crawler 1 provided with a short leader 2
Therefore, the crawler 1 can be carried in even in a narrow site or a site passing through a narrow site, and the boring rod 14 is telescopically fitted by telescopically fitting the short connecting steel pipes 14a and 14b. Therefore, it can be set on a short leader, can be extended stepwise for drilling at a sufficient depth when digging, and can be stepwise contracted and pulled up when the boring rod 14 is pulled up.

【００１２】連結鋼管１４ａ，１４ｂのロック機構２１
は、連結鋼管１４ａの内周円に接する接線Ｓを中心とし
た円筒状をなし、その内径が内側の連結鋼管１４ｂの係
止段部１９の肉厚寸法よりも小さく形成された円筒部２
２と、この円筒部２２内に回転自在に挿嵌され、その円
周の中間部に連結鋼管１４ａの内周面の軌跡に沿って円
弧状に切り取った円弧凹部２３を有するロックピン２４
とからなるため、ロックピン２４をその軸心回りに回転
調整するという極めて簡単な操作で、迅速かつ確実に連
結鋼管１４ａ，１４ｂを連結ロックしたり、これを解除
したりすることができると共に、円筒部２２及びロック
ピン２４の約半分が連結鋼管１４ａの内部に収まって突
出部分が少ないので、ロッド１４の掘進や回転の抵抗が
少なく、しかもロックピン２４の周囲のシール材２８に
より連結鋼管１４ａの内外間の止水を確実に行うことが
できる。Locking mechanism 21 for connecting steel pipes 14a, 14b
Has a cylindrical shape centered on a tangent line S that is in contact with the inner circumference of the connecting steel pipe 14a, and has an inner diameter smaller than the wall thickness of the locking step 19 of the inner connecting steel pipe 14b.
2 and a lock pin 24 that is rotatably inserted in the cylindrical portion 22 and that has an arc recess 23 that is cut in an arc shape along the locus of the inner peripheral surface of the connecting steel pipe 14a in the middle of the circumference thereof.
Therefore, it is possible to connect and lock the connecting steel pipes 14a and 14b quickly and surely and release it by an extremely simple operation of rotating the lock pin 24 about its axis. Approximately half of the cylindrical portion 22 and the lock pin 24 are accommodated in the inside of the connecting steel pipe 14a, and the protruding portion is small, so that resistance to excavation and rotation of the rod 14 is small, and the sealing material 28 around the lock pin 24 prevents the connecting steel pipe 14a Water can be reliably stopped between the inside and outside.

【００１３】[0013]

【実施例】図１に示すように、狭小地においても走行及
び方向転換可能な小型（例えば、1m前後の車幅と回転半
径をもったもの）のクローラー１に、短尺な（例えば、
3m〜4m程度）リーダー２がその中間部に設けたブラケッ
ト３において支持アーム４の先端に垂直状態から水平状
態にかけて回動自在に枢着され、このリーダー２はその
ブラケット３の近くのブラケット５と、支持アーム４の
基端を俯仰自在に枢着しているブラケット６の近くのブ
ラケット７との間に枢着された油圧シリンダー８により
回動するように構成されている。EXAMPLE As shown in FIG. 1, a small crawler 1 (for example, having a vehicle width of about 1 m and a turning radius) capable of traveling and changing direction even in a narrow area has a short length (for example,
The leader 2 is pivotally attached to the tip of the supporting arm 4 from a vertical state to a horizontal state in a bracket 3 provided at an intermediate portion of the leader 2, and the leader 2 is attached to a bracket 5 near the bracket 3. The base end of the support arm 4 is configured to rotate by a hydraulic cylinder 8 pivotally mounted between a bracket 6 and a bracket 7 near the bracket 6 which is pivotally mounted so as to be lifted and lowered.

【００１４】リーダー２には、搭載した電動又は油圧駆
動のモーター９により走行機構を介してガイド１０に沿
って昇降する昇降台１１及び下部支持台１２が設けら
れ、昇降台１１にはモーター９により回転駆動するロッ
ドチャック１３が設けられている。The reader 2 is provided with a lift base 11 and a lower support base 12 which are lifted and lowered along a guide 10 by a mounted electric or hydraulically driven motor 9 via a traveling mechanism, and the lift base 11 is driven by the motor 9. A rod chuck 13 that is rotationally driven is provided.

【００１５】リーダー２には、上端をロッドチャック１
３にチャッキングして取付けた伸縮式ボーリングロッド
１４がセットされている。The leader 2 has a rod chuck 1 at the upper end.
The telescopic boring rod 14 chucked and attached to the No. 3 is set.

【００１６】ボーリングロッド１４は図１２，図１３に
示すように、少なくとも２本の径の異なる短尺な（例え
ば、2.5m〜4m程度）連結鋼管１４ａ，１４ｂ・・をテレ
スコピック式に内外多重に嵌め合わしたもので、図１に
示すように最外側の連結鋼管１４ａにはその先端部周囲
に掘削羽根１５及び攪拌羽根１６、ならびに地盤硬化材
の吐出孔１７が設けられている。As shown in FIGS. 12 and 13, the boring rod 14 has at least two short-length (for example, about 2.5 m to 4 m) connecting steel pipes 14a, 14b .. As shown in FIG. 1, the outermost connecting steel pipe 14a is provided with an excavating blade 15, a stirring blade 16, and a ground hardening material discharge hole 17 around the tip portion thereof.

【００１７】外側の連結鋼管１４ａの上端部には内周側
に張り出した係止段部１８が設けられ、また内側の連結
鋼管１４ｂにはその下端部に外側に張り出した係止段部
１９が設けられ、各係止段部１８，１９の摺動面に接す
るＯリング等のシール材２０が設けられている。The outer connecting steel pipe 14a is provided at its upper end with a locking step 18 projecting toward the inner peripheral side, and the inner connecting steel pipe 14b is provided at its lower end with a locking step 19 projecting outward. A sealing material 20 such as an O-ring is provided which is provided and is in contact with the sliding surfaces of the locking step portions 18 and 19.

【００１８】外側の連結鋼管１４ａの上端部には、内外
の連結鋼管１４ａ，１４ｂを相互に引き延ばして端部を
連結ロックするためのロック機構２１が設けられてい
る。A lock mechanism 21 is provided at the upper end of the outer connecting steel pipe 14a for extending the inner and outer connecting steel pipes 14a and 14b to lock the ends.

【００１９】ロック機構２１は図９〜図１３に示すよう
に、連結鋼管１４ａの内周円に接する接線Ｓを中心とし
た円筒状をなし、その内径が内側の連結鋼管１４ｂの係
止段部１９の肉厚寸法よりも小さく形成された円筒部２
２と、この円筒部２２内に回転自在に挿嵌され、その円
周の中間部に連結鋼管１４ａの内周面の軌跡に沿って円
弧状に切り取った円弧凹部２３を有するロックピン２４
とからなり、このロックピン２４の円筒部２２から突出
した一端部はその外周に嵌合して止めピン２５で固定し
た係止リング２６に係止されており、またロックピン２
４の円筒部２２から突出した他端部にはレンチを嵌合し
て回転する角筒部、あるいは回転レバーを挿通する横孔
を有する軸端部等の回転操作部２７が設けられ、さらに
円筒部２２の両端部に摺接するロックピン２４の両端部
にはＯリング等のシール材２８が装着されている。As shown in FIGS. 9 to 13, the lock mechanism 21 has a cylindrical shape centered on a tangent line S contacting the inner circumferential circle of the connecting steel pipe 14a, and the inner diameter of the engaging step portion of the connecting steel pipe 14b. Cylindrical portion 2 formed to have a thickness smaller than 19
2 and a lock pin 24 that is rotatably inserted in the cylindrical portion 22 and that has an arc recess 23 that is cut in an arc shape along the locus of the inner peripheral surface of the connecting steel pipe 14a in the middle of the circumference thereof.
One end portion of the lock pin 24 protruding from the cylindrical portion 22 is engaged with an outer periphery of the lock pin 24 and is retained by a retaining ring 26 fixed by a retaining pin 25.
The other end projecting from the cylindrical portion 22 of No. 4 is provided with a rotating operation portion 27 such as a square tubular portion that rotates by fitting a wrench, or a shaft end portion having a lateral hole through which a rotary lever is inserted. A seal member 28 such as an O-ring is attached to both ends of the lock pin 24 that is in sliding contact with both ends of the portion 22.

【００２０】内側の連結鋼管１４ｂの下端の係止段部１
９の外周には、連結鋼管１４ａ，１４ｂを相互に引き延
ばして相互の係止段部１８，１９同士をつき当てた状態
において、円筒部２２の内周面の軌跡に沿って切り取っ
た円弧状凹部２９が設けられている。Locking step 1 at the lower end of the inner connecting steel pipe 14b
On the outer periphery of 9, the connecting steel pipes 14a and 14b are extended to each other, and the locking step portions 18 and 19 are brought into contact with each other, and an arcuate concave portion cut out along the locus of the inner peripheral surface of the cylindrical portion 22. 29 are provided.

【００２１】従って、ロックピン２４をその円弧状部２
３が外側の連結鋼管１４ａの内周面に沿った位置にくる
ように回転したときには、外側の連結鋼管１４ａ内にお
いて内側の連結鋼管１４ｂをその長手方向に自由にスラ
イドでき、また連結鋼管１４ａ，１４ｂを相互に引き延
ばして相互の係止段部１８，１９同士をつき当てた状態
においてロックピン２４を約半回転してその円弧状凹部
２３の無い外周部を内側の連結鋼管１４ｂの係止段部１
９の円弧状凹部２９に食い込ませて掛合させることによ
り連結鋼管１４ａ，１４ｂを連結ロックすることができ
る。Therefore, the lock pin 24 is attached to the arc-shaped portion 2 of the lock pin 24.
When 3 rotates so as to come to a position along the inner peripheral surface of the outer connecting steel pipe 14a, the inner connecting steel pipe 14b can freely slide in the longitudinal direction within the outer connecting steel pipe 14a, and the connecting steel pipe 14a, 14b are extended to each other and the locking step portions 18 and 19 are abutted against each other, the lock pin 24 is rotated about half a turn, and the outer peripheral portion without the arcuate recess 23 is locked step of the inner connecting steel pipe 14b. Part 1
The steel pipes 14a and 14b can be connected and locked by biting into the arcuate concave portion 29 of 9 and engaging with each other.

【００２２】内外の連結鋼管１４ａ，１４ｂの摺接部に
は、一方にキー３０が、また他方にこのキー３０が管の
長手方向に沿ってスライド自在に掛合するキー溝３１が
設けられ、これによって連結鋼管１４ａ，１４ｂが相対
的に回転することを阻止するようになっている。The sliding contact portions of the inner and outer connecting steel pipes 14a, 14b are provided with a key 30 on one side and a key groove 31 on the other side with which the key 30 is slidably engaged along the longitudinal direction of the pipe. This prevents the connecting steel pipes 14a and 14b from rotating relative to each other.

【００２３】次に上記のように構成された地盤改良装置
を用いて地盤改良を実施する工法について説明すると、
図２に示すように連結鋼管１４ａ，１４ｂを収縮した状
態のボーリングロッド１４をモーター９により回転しな
がら昇降台１１により加圧してリーダー２に沿って下降
させ、先端の掘削羽根１５により限界掘削長まで掘削し
た後、図３に示すように内側の連結鋼管１４ｂを引き出
してその上端をロッドチャック１３にチャッキングし、
昇降台１１を上昇させて連結鋼管１４ｂを引き出し限界
まで伸長させる。Next, the construction method for carrying out the ground improvement using the ground improvement apparatus configured as described above will be explained.
As shown in FIG. 2, the boring rod 14 in a state where the connecting steel pipes 14a and 14b are contracted is rotated by the motor 9 while being pressed by the elevating table 11 to be lowered along the leader 2, and the limit excavation length by the excavation blade 15 at the tip. After excavating up to, as shown in FIG. 3, the inner connecting steel pipe 14b is pulled out and the upper end thereof is chucked by the rod chuck 13,
The elevating table 11 is raised to pull out the connecting steel pipe 14b and extend it to the limit.

【００２４】このようにして連結鋼管１４ａ，１４ｂを
いっぱいまで引き出して相互の係止段部１８，１９同士
を突き当てた状態において、図１０及び図１３に示すよ
うにロックピン２４をその回転操作部２７においてレン
チ等を用いて約半回転することにより、その円弧状凹部
２３の無い外周部を内側の連結鋼管１４ｂの係止段部１
９の円弧状凹部２９に食い込ませて連結鋼管１４ａ，１
４ｂ相互を連結ロックする。In this way, with the connecting steel pipes 14a, 14b fully pulled out and the locking step portions 18, 19 abutting each other, as shown in FIGS. 10 and 13, the lock pin 24 is rotated. By rotating the portion 27 about half a turn using a wrench or the like, the outer peripheral portion without the arcuate recess 23 is locked by the step portion 1 of the inner connecting steel pipe 14b.
9 into the arcuate concave portion 29 to connect the connecting steel pipes 14a, 1
4b are connected and locked.

【００２５】次に、引き延ばして連結ロックされた連結
鋼管１４ａ，１４ｂをモーター９で回転させながら昇降
台１１を再び下降させ、図４に示すように先端の掘削羽
根１５により限界掘削長まで掘削する。Next, the elevating table 11 is lowered again while the connecting steel pipes 14a and 14b that have been extended and connected and locked are rotated by the motor 9, and as shown in FIG. 4, the excavation blades 15 at the tip end excavate to the limit excavation length. .

【００２６】連結鋼管１４ｂの内部にさらに連結鋼管１
４ｃが挿嵌されているときには、上記同様にこれを引き
出して連結ロックし、さらに掘進する。The connecting steel pipe 1 is further provided inside the connecting steel pipe 14b.
When 4c is inserted, it is pulled out in the same manner as described above to be connected and locked, and further excavated.

【００２７】このようにして所要深度まで掘削した後、
図５に示すようにボーリングロッド１４内にセメントミ
ルク等の地盤硬化材を圧送して吐出孔１７から削孔３２
内のの掘削土砂中に注入すると共に、ボーリングロッド
１４を回転しながら引き上げて攪拌羽根１６により土砂
を地盤硬化材と共に均一に攪拌する。After excavating to the required depth in this way,
As shown in FIG. 5, a ground hardening material such as cement milk is fed under pressure into the boring rod 14 to form a hole 32 from the discharge hole 17.
While being poured into the excavated earth and sand inside, the boring rod 14 is rotated and pulled up, and the earth and sand are evenly stirred together with the ground hardening material by the stirring blade 16.

【００２８】昇降台１１が上限に到達するまで引き延ば
されたボーリングロッド１４を引き上げた後（図６）、
図９及び図１２に示すようにロックピン２４をその円弧
状部２３が外側の連結鋼管１４ａの内周面に沿った位置
にくるように回転し、この状態で図７に示すように内側
の連結ロッド１４ｂを下降させて外側の連結ロッド１４
ａ内に挿嵌して収縮する。After pulling up the extended boring rod 14 until the lift 11 reaches the upper limit (FIG. 6),
As shown in FIGS. 9 and 12, the lock pin 24 is rotated so that the arcuate portion 23 thereof comes to a position along the inner peripheral surface of the outer connecting steel pipe 14a, and in this state, as shown in FIG. The connecting rod 14b is lowered to bring the connecting rod 14 outside.
It is inserted into a and contracts.

【００２９】その後は外側の連結ロッド１４ａの上端を
ロッドチャック１３にチャッキングし、これを図８に示
すように回転しながら引き上げて上記同様に注入した地
盤硬化材と共に削孔３２内の土砂を攪拌羽根１６により
均一に攪拌し、ボーリングロッド１４を引き上げた削孔
３２内の土砂を凝固させて地中造成杭３３を構築する。After that, the upper end of the outer connecting rod 14a is chucked to the rod chuck 13, which is rotated and pulled up as shown in FIG. 8 to remove the earth and sand in the drilled hole 32 together with the ground hardening material injected as described above. The stirring blade 16 uniformly stirs and solidifies the earth and sand in the drilled hole 32 in which the boring rod 14 is pulled up, thereby constructing an underground pile 33.

【００３０】以上の施工を順次所要間隔毎に連続して行
って多数の地中造成杭３３を隣接して構築することによ
り、支持力の不足した軟弱な地盤等を安定した地盤に改
良する。By constructing a large number of underground piles 33 adjacent to each other by successively performing the above-mentioned construction at required intervals, the soft ground having insufficient bearing capacity can be improved to a stable ground.

【００３１】なお、以上の構成においてロック機構２１
として他の機構のものを採用することができ、例えば図
１４に示すように、連結鋼管１４ａ，１４ｂを相互に引
き延ばして相互の係止段部１８，１９同士をつき当てた
状態において、連結鋼管１４ａ，１４ｂの重なり部分に
相互に連通するボルト孔３２，３３を設け、これにボル
ト３４をねじ込んで連結ロックするようにした機構など
を採用することができる。In the above structure, the lock mechanism 21
Other mechanisms can be adopted as the connecting steel pipes, for example, as shown in FIG. 14, when the connecting steel pipes 14a and 14b are extended to each other and the locking step portions 18 and 19 are brought into contact with each other. It is possible to employ a mechanism in which bolt holes 32 and 33 that communicate with each other are provided in the overlapping portions of 14a and 14b, and a bolt 34 is screwed into the bolt holes to lock the connection.

【００３２】[0032]

【発明の効果】以上の通りこの発明によれば、短尺なリ
ーダーを設けた小型のクローラーを用いるため、狭小地
の現場あるいは狭小地を通る現場においてもクローラー
を搬入することができ、またボーリングロッドは短尺な
連結鋼管をテレスコピック式に内外に嵌め合わして伸縮
自在としたので、短尺なリーダーにセットすることがで
き、掘進時には段階的に伸長して十分な深度の削孔を行
うことができ、またボーリングロッドの引き上げ時には
段階的に収縮して引き上げることができる。As described above, according to the present invention, since a small crawler provided with a short leader is used, the crawler can be carried in on a narrow site or through a narrow site, and a boring rod. Is a telescopic type that fits in and out telescopically so that it can be expanded and contracted, so it can be set on a short leader, and it can be extended stepwise during excavation and drilling with a sufficient depth, Further, when the boring rod is pulled up, it can be gradually contracted and pulled up.

【００３３】連結鋼管のロック機構は、連結鋼管の内周
円に接する接線を中心とした円筒状をなし、その内径が
内側の連結鋼管の係止段部の肉厚寸法よりも小さく形成
された円筒部と、この円筒部内に回転自在に挿嵌され、
その円周の中間部に連結鋼管の内周面の軌跡に沿って円
弧状に切り取った円弧凹部を有するロックピンとからな
るので、ロックピンを円筒部に挿嵌したままその軸心回
りに回転調整するという極めて簡単な操作で、迅速かつ
確実に連結鋼管を連結ロックしたり、これを解除したり
することができると共に、円筒部及びロックピンの約半
分が連結鋼管の内部に収まって突出部分が少ないので、
ロッドの掘進や回転の抵抗が少なく、しかもロックピン
周囲のシール材により連結鋼管の内外間の止水を確実に
行うことができる。The lock mechanism of the connected steel pipe has a cylindrical shape centered on a tangent line contacting the inner circumference circle of the connected steel pipe, and its inner diameter is formed smaller than the wall thickness of the locking step portion of the inner connected steel pipe. A cylindrical part, and is rotatably inserted in the cylindrical part,
It consists of a lock pin in the middle part of its circumference, which has an arcuate recess cut out in an arc shape along the locus of the inner peripheral surface of the connecting steel pipe.Therefore, while the lock pin is inserted into the cylindrical part, rotation adjustment is performed around its axis With this extremely simple operation, the connecting steel pipes can be connected and locked quickly and reliably, and this can also be released, and about half of the cylindrical part and the lock pin fit inside the connecting steel pipes and the protruding parts Because there are few
There is little resistance to the excavation and rotation of the rod, and moreover, the sealing material around the lock pin can reliably stop the water between the inside and outside of the connecting steel pipe.

【図面の簡単な説明】[Brief description of drawings]

【図１】この発明に係る地盤改良装置の側面図。FIG. 1 is a side view of a ground improvement device according to the present invention.

【図２】この発明に係る地盤改良装置による施工状態の
一例を示す縦断側面図。FIG. 2 is a vertical cross-sectional side view showing an example of a construction state by the ground improvement device according to the present invention.

【図３】この発明に係る地盤改良装置による施工状態の
一例を示す縦断側面図。FIG. 3 is a vertical cross-sectional side view showing an example of a construction state by the ground improvement device according to the present invention.

【図４】この発明に係る地盤改良装置による施工状態の
一例を示す縦断側面図。FIG. 4 is a vertical sectional side view showing an example of a construction state by the ground improvement device according to the present invention.

【図５】この発明に係る地盤改良装置による施工状態の
一例を示す縦断側面図。FIG. 5 is a vertical sectional side view showing an example of a construction state by the ground improvement device according to the present invention.

【図６】この発明に係る地盤改良装置による施工状態の
一例を示す縦断側面図。FIG. 6 is a vertical sectional side view showing an example of a construction state by the ground improvement device according to the present invention.

【図７】この発明に係る地盤改良装置による施工状態の
一例を示す縦断側面図。FIG. 7 is a vertical sectional side view showing an example of a construction state by the ground improvement device according to the present invention.

【図８】この発明に係る地盤改良装置による施工状態の
一例を示す縦断側面図。FIG. 8 is a vertical sectional side view showing an example of a construction state by the ground improvement device according to the present invention.

【図９】この発明に係る連結鋼管の連結ロック機構の連
結ロック解除の状態を示す縦断平面図。FIG. 9 is a vertical cross-sectional plan view showing the connection lock release state of the connection lock mechanism of the connection steel pipe according to the present invention.

【図１０】この発明に係る連結鋼管の連結ロック機構の
連結ロック時の状態を示す縦断平面図。FIG. 10 is a vertical cross-sectional plan view showing a state when the connection lock mechanism of the connection steel pipe according to the present invention is in the connection lock state.

【図１１】この発明に係る連結鋼管の連結ロック機構の
ロックピンの平面図。FIG. 11 is a plan view of a lock pin of a connection lock mechanism for a connection steel pipe according to the present invention.

【図１２】この発明に係る連結鋼管の連結ロック機構の
連結ロック解除の状態を示す縦断平面図。FIG. 12 is a vertical cross-sectional plan view showing the connection lock release state of the connection lock mechanism of the connection steel pipe according to the present invention.

【図１３】この発明に係る連結鋼管の連結ロック機構の
連結ロック時の状態を示す縦断平面図。FIG. 13 is a vertical cross-sectional plan view showing a state when the connection lock mechanism of the connection steel pipe according to the present invention is in the connection lock state.

【図１４】この発明に係る連結鋼管の他の連結ロック機
構における連結ロック時の状態を示す縦断平面図。FIG. 14 is a vertical cross-sectional plan view showing a state when the connection lock is achieved in another connection lock mechanism of the connection steel pipe according to the present invention.

【符号の説明】１クローラー２リーダー３ブラケット４支持アーム５ブラケット６ブラケット７ブラケット８油圧シリンダー９モーター１０ガイド１１昇降台１２下部支持台１３ロッドチャック１４ボーリングロッド１４ａ外側連結鋼管１４ｂ内側連結鋼管１５掘削羽根１６攪拌羽根１７吐出孔１８係止段部１９係止段部２０シール材２１ロック機構２２円筒部２３円弧凹部２４ロックピン２５止めピン２６係止リング２７回転操作部２８シール材２９円弧状凹部３０キー３１キー溝３２削孔３３地中造成杭Ｓ接線[Explanation of Codes] 1 Crawler 2 Reader 3 Bracket 4 Support Arm 5 Bracket 6 Bracket 7 Bracket 8 Hydraulic Cylinder 9 Motor 10 Guide 11 Lifting Platform 12 Lower Support Platform 13 Rod Chuck 14 Boring Rod 14a Outer Connection Steel Pipe 14b Inner Connection Steel Pipe 15 Drilling Blade 16 Stirring Blade 17 Discharge Hole 18 Locking Step 19 Locking Step 20 Sealing Material 21 Locking Mechanism 22 Cylindrical Section 23 Circular Cavity 24 Lock Pin 25 Stopping Pin 26 Locking Ring 27 Rotating Operating Section 28 Sealing Material 29 Circular Cavity 30 key 31 key groove 32 drilling hole 33 underground pile S tangent

Claims

【特許請求の範囲】[Claims]

【請求項１】狭小地においても走行及び方向転換可能
な小型のクローラーに設けた短尺なリーダーに、ガイド
に沿って昇降する昇降台が設けられ、昇降台にはモータ
ーにより回転駆動するロッドチャックが設けられ、リー
ダーには上端を前記ロッドチャックにチャッキングして
取付けた伸縮式ボーリングロッドがセットされ、前記ボ
ーリングロッドは少なくとも２本の径の異なる短尺な連
結鋼管をテレスコピック式に内外に嵌め合わしてなり、
最外側の前記連結鋼管にはその先端部周囲に掘削羽根及
び攪拌羽根ならびに地盤硬化材の吐出孔が設けられ、外
側の連結鋼管の上端部には、内外の連結鋼管を相互に引
き延ばして端部を連結ロックするためのロック機構が設
けられていることを特徴とする小型地盤改良装置。1. A short reader provided on a small crawler capable of traveling and changing direction even in a narrow land is provided with a lifting platform that is lifted and lowered along a guide, and a rod chuck that is rotationally driven by a motor is mounted on the lifting platform. The leader is provided with a telescopic boring rod whose upper end is chucked and attached to the rod chuck. The boring rod is formed by telescopically fitting at least two short connecting steel pipes having different diameters inside and outside. Becomes
The outermost connecting steel pipe is provided with a drilling blade, a stirring blade, and a ground hardening material discharge hole around its tip, and the upper and lower ends of the outer connecting steel pipe are formed by mutually extending the inner and outer connecting steel pipes. A small ground improvement device, which is provided with a lock mechanism for connecting and locking the ground.

【請求項２】狭小地においても走行及び方向転換可能
な小型のクローラーに設けた短尺なリーダーに、ガイド
に沿って昇降する昇降台が設けられ、昇降台にはモータ
ーにより回転駆動するロッドチャックが設けられ、リー
ダーには上端を前記ロッドチャックにチャッキングして
取付けた伸縮式ボーリングロッドがセットされ、前記ボ
ーリングロッドは少なくとも２本の径の異なる短尺な連
結鋼管をテレスコピック式に内外に嵌め合わしてなり、
最外側の前記連結鋼管にはその先端部周囲に掘削羽根及
び攪拌羽根ならびに地盤硬化材の吐出孔が設けられ、外
側の連結鋼管の上端部には内周側に張り出した係止段部
が、また内側の連結鋼管にはその下端部に外側に張り出
した係止段部が設けられ、外側の連結鋼管の上端部に
は、内外の連結鋼管を相互に引き延ばして端部を連結ロ
ックするためのロック機構が設けられ、前記ロック機構
は、外側の連結鋼管の内周円に接する接線を中心とした
円筒状をなし、その内径が内側の連結鋼管の係止段部の
肉厚寸法よりも小さく形成された円筒部と、この円筒部
内に回転自在に挿嵌され、その円周の中間部に連結鋼管
の内周面の軌跡に沿って円弧状に切り取った円弧凹部を
有するロックピンとからなり、内側の連結鋼管の下端の
係止段部の外周には、内外の連結鋼管を相互に引き延ば
して相互の係止段部同士をつき当てた状態において、円
筒部の内周面の軌跡に沿って切り取った円弧状凹部が設
けられていることを特徴とする小型地盤改良装置。2. A short reader provided on a small crawler capable of traveling and changing direction even in a narrow land is provided with a lifting platform that moves up and down along a guide, and a rod chuck that is rotationally driven by a motor is mounted on the lifting platform. The leader is provided with a telescopic boring rod whose upper end is chucked and attached to the rod chuck. The boring rod is formed by telescopically fitting at least two short connecting steel pipes having different diameters inside and outside. Becomes
The outermost connecting steel pipe is provided with a drilling blade, a stirring blade, and a ground hardening material discharge hole around the tip end portion thereof, and an engaging step portion protruding to the inner peripheral side is provided at the upper end portion of the outer connecting steel pipe, Further, the inner connecting steel pipe is provided with a locking step portion protruding outward at the lower end portion thereof, and the upper end portion of the outer connecting steel pipe is for extending the inner and outer connecting steel pipes to each other to lock the end portions together. A lock mechanism is provided, and the lock mechanism has a cylindrical shape centered on a tangent line contacting the inner circumferential circle of the outer connecting steel pipe, and its inner diameter is smaller than the wall thickness dimension of the locking step portion of the inner connecting steel pipe. A formed cylindrical portion and a lock pin that is rotatably inserted in the cylindrical portion and has an arc recess cut in an arc shape along the locus of the inner peripheral surface of the connecting steel pipe in the middle part of its circumference, On the outer periphery of the locking step at the lower end of the inner connecting steel pipe Small size characterized in that an arcuate recess cut out along the locus of the inner peripheral surface of the cylindrical portion is provided in a state in which the inner and outer connecting steel pipes are extended to each other and the locking step portions are abutted against each other. Ground improvement device.

【請求項３】狭小地においても走行及び方向転換可能
な小型のクローラーに設けた短尺なリーダーに、ガイド
に沿って昇降する昇降台が設けられ、昇降台にはモータ
ーにより回転駆動するロッドチャックが設けられ、リー
ダーには上端を前記ロッドチャックにチャッキングして
取付けた伸縮式ボーリングロッドがセットされ、前記ボ
ーリングロッドは少なくとも２本の径の異なる短尺な連
結鋼管をテレスコピック式に内外に嵌め合わしてなり、
最外側の前記連結鋼管にはその先端部周囲に掘削羽根及
び攪拌羽根ならびに地盤硬化材の吐出孔が設けられ、外
側の連結鋼管の上端部には内周側に張り出した係止段部
が、また内側の連結鋼管にはその下端部に外側に張り出
した係止段部が設けられ、各係止段部にはシール材が設
けられ、外側の連結鋼管の上端部には、内外の連結鋼管
を相互に引き延ばして端部を連結ロックするためのロッ
ク機構が設けられ、前記ロック機構は、外側の連結鋼管
の内周円に接する接線を中心とした円筒状をなし、その
内径が内側の連結鋼管の係止段部の肉厚寸法よりも小さ
く形成された円筒部と、この円筒部内に回転自在に挿嵌
され、その円周の中間部に連結鋼管の内周面の軌跡に沿
って円弧状に切り取った円弧凹部を有するロックピンと
からなり、円筒部の両端部に摺接するロックピンの両端
部にはシール材が装着され、内側の連結鋼管の下端の係
止段部の外周には、内外の連結鋼管を相互に引き延ばし
て相互の係止段部同士をつき当てた状態において、円筒
部の内周面の軌跡に沿って切り取った円弧状凹部が設け
られていることを特徴とする小型地盤改良装置。3. A short reader provided on a small crawler capable of traveling and changing direction even in a narrow land is provided with a lifting platform that moves up and down along a guide, and a rod chuck that is rotationally driven by a motor is provided on the lifting platform. The leader is provided with a telescopic boring rod whose upper end is chucked and attached to the rod chuck. The boring rod is formed by telescopically fitting at least two short connecting steel pipes having different diameters inside and outside. Becomes
The outermost connecting steel pipe is provided with a drilling blade, a stirring blade, and a ground hardening material discharge hole around the tip end portion thereof, and an engaging step portion protruding to the inner peripheral side is provided at the upper end portion of the outer connecting steel pipe, Further, the inner connecting steel pipe is provided with a locking step portion projecting outward at the lower end thereof, a sealing material is provided on each locking step portion, and the inner connecting steel pipe is connected to the upper end of the outer connecting steel pipe. Is provided with a locking mechanism for connecting and locking the ends by interlocking, and the locking mechanism has a cylindrical shape centered on a tangent line contacting the inner circumferential circle of the outer connecting steel pipe, the inner diameter of which is the inner connecting A cylindrical portion formed to be smaller than the wall thickness of the locking step portion of the steel pipe, and rotatably inserted into the cylindrical portion. A circular portion is formed along the locus of the inner peripheral surface of the connecting steel pipe at an intermediate portion of its circumference. A lock pin having an arcuate recess cut in an arc shape, and a cylindrical part Sealing materials are attached to both ends of the lock pin that slides in contact with both ends, and the inner and outer connecting steel pipes are extended to each other on the outer periphery of the lower engaging step of the inner connecting steel pipe. A small ground improvement device, characterized in that an arcuate concave portion cut out along the locus of the inner peripheral surface of the cylindrical portion is provided in the state of abutting against.

【請求項４】少なくとも２本の径の異なる短尺な連結
鋼管をテレスコピック式に内外に嵌め合わしてなり、最
外側の前記連結鋼管にはその先端部周囲に掘削羽根及び
攪拌羽根ならびに地盤硬化材の吐出孔が設けられ、外側
の連結鋼管の上端部には、内外の連結鋼管を相互に引き
延ばして端部を連結ロックするためのロック機構が設け
られた伸縮式ボーリングロッドを、狭小地においても走
行及び方向転換可能な小型のクローラーに設けた短尺な
リーダーにセットし、その上端を前記リーダーに沿って
昇降自在に設けた昇降台にモーターにより回転駆動可能
に設けたロッドチャックにチャッキングして取付け、前
記ボーリングロッドをモーターにより回転しながら昇降
台により加圧してリーダーに沿って下降させ、先端の掘
削羽根により限界掘削長まで掘削した後、内側の連結鋼
管を引き出してその上端をロッドチャックにチャッキン
グし、昇降台を上昇させて連結鋼管を引き出し限界まで
伸長させ、前記ロック機構により連結鋼管相互を連結ロ
ックし、次に引き延ばして連結ロックされた連結鋼管を
モーターで回転させながら昇降台を再び下降させ、先端
の掘削羽根により限界掘削長まで掘削した後、ボーリン
グロッド内にセメントミルク等の地盤硬化材を圧送して
吐出孔から周辺の掘削土砂中に注入すると共に、ボーリ
ングロッドを回転しながら引き上げて攪拌羽根により土
砂を地盤硬化材と共に均一に攪拌し、昇降台が上限に到
達するまで引き延ばされたボーリングロッドを引き上げ
た後、前記ロック機構による内外の連結ロッドの連結ロ
ックを解除して内側の連結ロッドを下降させて外側の連
結ロッド内に挿嵌して収縮し、その後は外側の連結ロッ
ドの上端をロッドチャックにチャッキングし、これを回
転しながら引き上げて上記同様に注入した地盤硬化材と
共に土砂を攪拌羽根により均一に攪拌し、ボーリングロ
ッドを引き上げた削孔内の土砂を凝固させて地中造成杭
を構築することを特徴とする地盤改良工法。4. At least two short connecting steel pipes having different diameters are telescopically fitted inside and outside, and the outermost connecting steel pipe is provided with a drilling blade, a stirring blade, and a ground hardening material around its tip. A telescopic boring rod equipped with a discharge hole and a locking mechanism for connecting and locking the ends of the outer connecting steel pipes by extending the inner and outer connecting steel pipes to each other at the upper end of the connecting steel pipes, even when running in narrow areas And set on a short leader provided on a small crawler that can change direction, and the upper end of the leader is chucked and attached to a rod chuck that can be driven to rotate by a motor on an elevator table that can be raised and lowered along the leader. While rotating the boring rod with a motor, pressurize it with an elevating table to lower it along the leader, and limit excavation with the excavating blade at the tip. After excavating to the length of the cut, pull out the inner connecting steel pipe and chuck the upper end to the rod chuck, raise the elevating table to extend the connecting steel pipe to the pulling limit, and connect and lock the connecting steel pipes by the lock mechanism. Next, while pulling out and connecting and locking the connected connected steel pipe with a motor, lower the elevator base again and excavate to the limit excavation length with the tip excavation blade, then pump the ground hardening material such as cement milk into the boring rod. Then, it was poured into the surrounding excavated soil from the discharge hole, and the boring rod was rotated and pulled up, the soil was evenly stirred with the ground hardening material by the stirring blade, and it was extended until the lifting platform reached the upper limit. After pulling up the boring rod, release the connection lock of the inner and outer connecting rods by the locking mechanism and lower the inner connecting rod. Then, it is inserted into the outer connecting rod and contracts, and then the upper end of the outer connecting rod is chucked to the rod chuck, and it is pulled up while rotating to agitate the earth and sand together with the ground hardening material injected as above. A ground improvement method characterized by constructing an underground pile by solidifying the sand and sand in the drilled hole where the boring rod is pulled up by uniformly stirring with a blade.

【請求項５】少なくとも２本の径の異なる短尺な連結
鋼管をテレスコピック式に内外に嵌め合わしてなり、最
外側の前記連結鋼管にはその先端部周囲に掘削羽根及び
攪拌羽根ならびに地盤硬化材の吐出孔が設けられ、外側
の連結鋼管の上端部には内周側に張り出した係止段部
が、また内側の連結鋼管にはその下端部に外側に張り出
した係止段部が設けられ、外側の連結鋼管の上端部に
は、内外の連結鋼管を相互に引き延ばして端部を連結ロ
ックするためのロック機構が設けられ、前記ロック機構
は、外側の連結鋼管の内周円に接する接線を中心とした
円筒状をなし、その内径が内側の連結鋼管の係止段部の
肉厚寸法よりも小さく形成された円筒部と、この円筒部
内に回転自在に挿嵌され、その円周の中間部に連結鋼管
の内周面の軌跡に沿って円弧状に切り取った円弧凹部を
有するロックピンとからなり、内側の連結鋼管の下端の
係止段部の外周には、内外の連結鋼管を相互に引き延ば
して相互の係止段部同士をつき当てた状態において、円
筒部の内周面の軌跡に沿って切り取った円弧状凹部が設
けられている伸縮式ボーリングロッドを、狭小地におい
ても走行及び方向転換可能な小型のクローラーに設けた
短尺なリーダーにセットし、その上端を前記リーダーに
沿って昇降自在に設けた昇降台にモーターにより回転駆
動可能に設けたロッドチャックにチャッキングして取付
け、前記ボーリングロッドをモーターにより回転しなが
ら昇降台により加圧してリーダーに沿って下降させ、先
端の掘削羽根により限界掘削長まで掘削した後、内側の
連結鋼管を引き出してその上端をロッドチャックにチャ
ッキングし、昇降台を上昇させて連結鋼管を引き出し限
界まで伸長させ、相互の係止段部同士をつき当てた状態
において、ロックピンを約半回転することにより、その
円弧状凹部の無い外周部を内側の連結鋼管の係止段部の
円弧状凹部に食い込ませて連結鋼管相互を連結ロック
し、次に引き延ばして連結ロックされた連結鋼管をモー
ターで回転させながら昇降台を再び下降させ、先端の掘
削羽根により限界掘削長まで掘削した後、ボーリングロ
ッド内にセメントミルク等の地盤硬化材を圧送して吐出
孔から周辺の掘削土砂中に注入すると共に、ボーリング
ロッドを回転しながら引き上げて攪拌羽根により土砂を
地盤硬化材と共に均一に攪拌し、昇降台が上限に到達す
るまで引き延ばされたボーリングロッドを引き上げた
後、ロックピンをその円弧状部が外側の連結鋼管の内周
面に沿った位置にくるように回転し、この状態で内側の
連結ロッドを下降させて外側の連結ロッド内に挿嵌して
収縮し、その後は外側の連結ロッドの上端をロッドチャ
ックにチャッキングし、これを回転しながら引き上げて
上記同様に注入した地盤硬化材と共に土砂を攪拌羽根に
より均一に攪拌し、ボーリングロッドを引き上げた削孔
内の土砂を凝固させて地中造成杭を構築することを特徴
とする地盤改良工法。5. At least two short connecting steel pipes having different diameters are telescopically fitted inside and outside, and the outermost connecting steel pipe is provided with a drilling blade, a stirring blade, and a ground hardening material around its tip. A discharge hole is provided, a locking step portion that projects to the inner peripheral side is provided at the upper end portion of the outer connecting steel pipe, and a locking step portion that projects to the outside is provided at the lower end portion of the inner connecting steel pipe. At the upper end of the outer connecting steel pipe, a lock mechanism for connecting and locking the end portions by extending the inner and outer connecting steel pipes to each other is provided, and the lock mechanism has a tangent line tangent to the inner circumference circle of the outer connecting steel pipe. A cylindrical part that has a cylindrical shape with the inner diameter smaller than the wall thickness of the locking step of the inner connecting steel pipe, and is rotatably inserted into this cylindrical part, and the middle of its circumference Along the trajectory of the inner peripheral surface of the steel pipe It consisted of a lock pin having an arcuate recess cut in an arc shape, and the inner and outer connecting steel pipes were extended to each other on the outer periphery of the engaging step part at the lower end of the inner connecting steel pipe, and the mutual engaging step parts were abutted. In this state, the telescopic boring rod, which has an arcuate recess cut out along the locus of the inner peripheral surface of the cylindrical part, is used as a short leader provided on a small crawler that can run and change direction even in narrow land. Set and chuck the upper end of the bobbin to a rod chuck that is rotatably driven by a motor on an elevator that is vertically movable along the reader, and press the boring rod by the motor while rotating the boring rod. Down along the leader and excavating to the limit excavation length with the excavation blade at the tip, pull out the inner connecting steel pipe and When the locking pin is chucked, the lifting platform is lifted to extend the connecting steel pipe to the limit, and the locking steps are brought into contact with each other, the lock pin is rotated about half a turn to form an arc-shaped recess. The outer peripheral part that does not have a groove is bitten into the arcuate recess of the locking step of the inner connecting steel pipe to connect and lock the connecting steel pipes, and then the connecting steel pipes are extended to rotate the connecting and locked steel pipes with the motor, and the lifting platform is re-engaged. After descending and excavating to the limit excavation length with the tip of the excavation blade, ground hardening material such as cement milk is pumped into the boring rod and injected into the surrounding excavated soil from the discharge hole, while rotating the boring rod. Pull up and stir evenly the sand and sand together with the ground hardening material, and pull up the extended boring rod until the elevator reaches the upper limit. The pin is rotated so that its arcuate portion comes to a position along the inner peripheral surface of the outer connecting steel pipe, and in this state, the inner connecting rod is lowered to be inserted into the outer connecting rod and contracted, After that, the upper end of the outer connecting rod is chucked to the rod chuck, and while pulling it while rotating it, the sand and sand together with the ground hardening material injected as above are uniformly stirred by the stirring blade, and the boring rod is pulled up inside the drilled hole. A soil improvement method characterized by solidifying soil and sand to construct underground piles.

【請求項６】少なくとも２本の径の異なる短尺な連結
鋼管をテレスコピック式に内外に嵌め合わしてなり、最
外側の前記連結鋼管にはその先端部周囲に掘削羽根及び
攪拌羽根ならびに地盤硬化材の吐出孔が設けられ、外側
の連結鋼管の上端部には内周側に張り出した係止段部
が、また内側の連結鋼管にはその下端部に外側に張り出
した係止段部が設けられ、外側の連結鋼管の上端部に
は、内外の連結鋼管を相互に引き延ばして端部を連結ロ
ックするためのロック機構が設けられ、前記ロック機構
は、外側の連結鋼管の内周円に接する接線を中心とした
円筒状をなし、その内径が内側の連結鋼管の係止段部の
肉厚寸法よりも小さく形成された円筒部と、この円筒部
内に回転自在に挿嵌され、その円周の中間部に連結鋼管
の内周面の軌跡に沿って円弧状に切り取った円弧凹部を
有するロックピンとからなり、内側の連結鋼管の下端の
係止段部の外周には、内外の連結鋼管を相互に引き延ば
して相互の係止段部同士をつき当てた状態において、円
筒部の内周面の軌跡に沿って切り取った円弧状凹部が設
けられていることを特徴とするボーリングロッド。6. At least two short connecting steel pipes having different diameters are telescopically fitted inside and outside, and the outermost connecting steel pipe has a drilling blade, a stirring blade, and a ground hardening material around its tip. A discharge hole is provided, a locking step portion that projects to the inner peripheral side is provided at the upper end portion of the outer connecting steel pipe, and a locking step portion that projects to the outside is provided at the lower end portion of the inner connecting steel pipe. At the upper end of the outer connecting steel pipe, a lock mechanism for connecting and locking the end portions by extending the inner and outer connecting steel pipes to each other is provided, and the lock mechanism has a tangent line tangent to the inner circumference circle of the outer connecting steel pipe. A cylindrical part that has a cylindrical shape with the inner diameter smaller than the wall thickness of the locking step of the inner connecting steel pipe, and is rotatably inserted into this cylindrical part, and the middle of its circumference Along the trajectory of the inner peripheral surface of the steel pipe It consisted of a lock pin having an arcuate recess cut in an arc shape, and the inner and outer connecting steel pipes were extended to each other on the outer periphery of the engaging step part at the lower end of the inner connecting steel pipe, and the mutual engaging step parts were abutted. A boring rod, characterized in that in the state, an arcuate recess cut out along the locus of the inner peripheral surface of the cylindrical portion is provided.