JP2905129B2 - Ground improvement method - Google Patents
Ground improvement methodInfo
- Publication number
- JP2905129B2 JP2905129B2 JP28135695A JP28135695A JP2905129B2 JP 2905129 B2 JP2905129 B2 JP 2905129B2 JP 28135695 A JP28135695 A JP 28135695A JP 28135695 A JP28135695 A JP 28135695A JP 2905129 B2 JP2905129 B2 JP 2905129B2
- Authority
- JP
- Japan
- Prior art keywords
- ground
- excavation
- hole
- scp
- ground improvement
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、埋立て地等におけ
る軟弱地盤の改良工法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving soft ground in a landfill or the like.
【０００２】[0002]
【従来の技術】一般に、埋立て地等における軟弱な地盤
に構造物を造るような場合、砂地盤の液状化を防止した
り、支持力を増加させるため、地盤の強度を増加させる
工事が事前に行われる。このような工事を行うものとし
ては種々の工法が実用化されているが、粘性土、砂層の
どちらにも有効であり、比較的安価な工法としてサンド
コンパクションパイル工法（ＳＣＰ工法）がある。2. Description of the Related Art In general, when a structure is to be built on soft ground in a landfill site, etc., construction to increase the strength of the ground in order to prevent liquefaction of the sand ground and increase the bearing capacity is required. Done in Although various construction methods have been put into practical use for performing such construction, there is a sand compaction pile method (SCP method) which is effective for both clayey soil and sand layer and is relatively inexpensive.
【０００３】図８はＳＣＰ工法の概要を示す図である。
図８に示すように、頂部にバイブロハンマー（図示せ
ず）を装着した鋼製のガイドパイプ１０３を地盤１０１
内に貫入させ、ガイドパイプ１０３の内部に砂を投入し
て、ガイドパイプ１０３に振動と上下の動きを与えるこ
とによって、地盤１０１内部にガイドパイプ１０３の径
より大きな径を有する砂杭１０７を構築する。なお、扉
１０５はガイドパイプ１０３の先端に蝶版で取り付けら
れ、ガイドパイプ１０３の引き抜き時に開いた状態とな
って、ガイドパイプ１０３内の砂を落とし、ガイドパイ
プ１０３の押し込み時にはガイドパイプ１０３の先端を
閉塞して投入された砂を加圧する。FIG. 8 is a diagram showing an outline of the SCP method.
As shown in FIG. 8, a steel guide pipe 103 having a vibratory hammer (not shown) mounted on the top is connected to the ground 101.
The sand pile 107 having a diameter larger than the diameter of the guide pipe 103 is constructed inside the ground 101 by introducing sand into the inside of the guide pipe 103 and giving vibration and vertical movement to the guide pipe 103. I do. Note that the door 105 is attached to the tip of the guide pipe 103 with a butterfly plate, and is opened when the guide pipe 103 is pulled out, drops sand in the guide pipe 103, and pushes the tip of the guide pipe 103 when the guide pipe 103 is pushed in. Is closed and the injected sand is pressurized.
【０００４】しかしながら、ＳＣＰ工法を行うと近接し
ている構造物や敷地に対して以下のような問題を生じる
ので、都市部ではＳＣＰ工法は採用しにくい。まず第１
に、ガイドパイプ１０３の径以上に拡大した砂杭１０７
を造っていくため、地盤改良部分の外側に地盤が押し出
され、近接の敷地やそこに造られている構造物を変形さ
せることがある。[0004] However, when the SCP method is used, the following problems occur with respect to a nearby structure or site. Therefore, it is difficult to adopt the SCP method in an urban area. First,
The sand pile 107 expanded beyond the diameter of the guide pipe 103
As a result, the ground may be pushed out of the ground improvement area, deforming nearby premises and structures built there.
【０００５】第２に、ガイドパイプ１０３の頂部にバイ
ブロハンマー（図示せず）を装着し、ガイドパイプ１０
３を振動させることによって、ガイドパイプ１０３の打
ち込みや投入された砂の締め固めを行うので、近接の敷
地やそこに造られる構造物に振動を与える。[0005] Second, a vibro hammer (not shown) is mounted on the top of the guide pipe 103, and
By vibrating 3, the driving of the guide pipe 103 and the compaction of the injected sand are performed, so that vibration is applied to a nearby site or a structure built there.
【０００６】[0006]
【発明が解決しようとする課題】このため、軟弱地盤の
改良を行う場合、以下のような方法が採られる。 （ａ）ＳＣＰ工法を採用せず、ＳＭＷ（Soil Mixing Wa
ll）工法を採用する。ＳＭＷ工法は地盤をオーガーで掘
削し、掘削された部分にセメントミルクを注入して攪拌
する。しかしながら、ＳＣＰ工法のような非振動系、非
膨張性の工法を採用すると、振動変位の問題はなくなる
が、非常にコストが上昇する共にモルタル作成のための
プラント設備が必要となり、作業ヤードが必要となる。For this reason, the following method is used to improve soft ground. (A) Without using SCP method, SMW (Soil Mixing Wa
ll) Use the construction method. In the SMW method, the ground is excavated with an auger, and cement milk is injected into the excavated portion and stirred. However, if a non-vibration system or non-expansive construction method such as the SCP method is used, the problem of vibration displacement is eliminated, but the cost is extremely increased and plant equipment for mortar preparation is required, and a work yard is required. Becomes
【０００７】（ｂ）図９に示すように、ＳＣＰ工法を行
う場所と隣接地１１２との間に緩衝溝１１１を設ける。
図９において１０１は地盤、１０９はサンドコンパクシ
ョンパイルである。このように、緩衝溝１１１を設ける
ことは安価であり、よく用いられるが、深い緩衝溝１１
１は造りにくいので効果は少ない。とくに、サンドコン
パクションパイル１０９の改良深さが深い場合には、緩
衝溝１１１の下を変位、振動が隣接地１１２まで伝達さ
れる。(B) As shown in FIG. 9, a buffer groove 111 is provided between a place where the SCP method is to be performed and an adjacent land 112.
In FIG. 9, 101 is the ground, and 109 is a sand compaction pile. As described above, the provision of the buffer groove 111 is inexpensive and is often used.
1 is less effective because it is difficult to make. In particular, when the improvement depth of the sand compaction pile 109 is deep, displacement and vibration are transmitted below the buffer groove 111 to the adjacent ground 112.
【０００８】（ｃ）図１０に示すように、ＳＣＰ工法を
行う場所と隣接地１１４との間に緩衝パイプ１１３を設
ける。図１０において１０１は地盤、１０９はサンドコ
ンパクションパイルである。緩衝パイプ１１３は、オー
ガー等により地盤１０１を削孔し、地盤１０１を緩めた
ものである。この場合、ＳＣＰ工法を行う場所と隣接地
１１４との間に緩んだ地盤が造られ、振動、変位の伝達
が抑制され、必要な深さまで緩衝パイプ１１３を造るこ
とが可能であり、効果も大きい。しかしながら、ＳＣＰ
工法の作業によって緩んだ地盤が締め固まり、長く効果
が続かないので、何度もオーガー等を用いて地盤１０１
を緩める作業が必要となる。(C) As shown in FIG. 10, a buffer pipe 113 is provided between the place where the SCP method is performed and the adjacent land 114. In FIG. 10, 101 is the ground, and 109 is a sand compaction pile. The buffer pipe 113 is formed by drilling the ground 101 with an auger or the like and loosening the ground 101. In this case, a loose ground is created between the place where the SCP method is performed and the adjacent ground 114, transmission of vibration and displacement is suppressed, and the buffer pipe 113 can be formed to a required depth, and the effect is large. . However, SCP
Since the loosened ground is compacted by the work of the construction method and the effect does not continue for a long time, the ground 101 is repeatedly used with an auger or the like.
Work is required to loosen.
【０００９】本発明は、このような問題に鑑みてなされ
たもので、その目的とするところは、コストが安く、隣
接地への振動、変位の伝達が抑制される地盤改良工法を
提供することにある。The present invention has been made in view of such a problem, and an object of the present invention is to provide a ground improvement method which is inexpensive and suppresses transmission of vibration and displacement to an adjacent land. It is in.
【００１０】[0010]
【課題を解決するための手段】 前述した目的を達成す
るために第１の発明は、地盤改良を行う地盤の周辺に複
数の掘削孔を設け、該掘削孔の上部にパイプを立て、該
パイプ及び該掘削孔内部に液体を装填したゴムチューブ
を設置する工程と、地盤改良を行う地盤内に砂杭を振動
させつつ構築する工程と、前記ゴムチューブ内にモルタ
ルを流し込みつつ、前記液体を排出して、前記掘削孔を
閉じる工程と、を具備することを特徴とする地盤改良工
法である。Means for Solving the Problems In order to achieve the above object, a first aspect of the present invention is to provide a plurality of excavation holes around the ground for improving the ground, and set up a pipe above the excavation holes, A step of installing a rubber tube loaded with a liquid inside the borehole, a step of vibrating a sand pile in the ground for ground improvement, and discharging the liquid while pouring mortar into the rubber tube. And closing the excavation hole.
【００１１】 第２の発明は、地盤改良を行う地盤の周
辺に複数の掘削孔を設け、該掘削孔内部に中央部に孔を
有する円筒状のクッション材を設ける工程と、地盤改良
を行う地盤内に砂杭を振動させつつ構築する工程と、前
記クッション材の中央の孔を用いてモルタルを注入し、
前記掘削孔を閉じる工程と、を具備することを特徴とす
る地盤改良工法である。A second invention provides a step of providing a plurality of excavation holes around the ground for improving the ground and providing a cylindrical cushion material having a hole in the center in the inside of the excavation holes, In the process of building while vibrating the sand pile in, and inject mortar using the center hole of the cushion material,
And a step of closing the excavation hole.
【００１２】[0012]
【発明の実施の形態】以下、図面に基づいて本発明の実
施の形態を詳細に説明する。図１は、本発明の第１の実
施の形態に係る地盤改良工法の概要図である。図１にお
いて１は地盤、３は地下水面、９はサンドコンパクショ
ンパイルであり、ＳＣＰ工法が用いられる場所と隣接地
４との間に緩衝帯５が設けられ、緩衝帯５内に緩衝体７
が設けられる。Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram of a ground improvement method according to the first embodiment of the present invention. In FIG. 1, 1 is the ground, 3 is the groundwater table, 9 is the sand compaction pile, and a buffer band 5 is provided between the place where the SCP method is used and the adjacent land 4.
Is provided.
【００１３】図２は緩衝体７の縦断面図、図３は図２の
Ａ−Ａによる断面図、図４は図２のＢ−Ｂによる断面図
である。緩衝体７を構築する場合、まず地盤１内をオー
ガー等で削孔し、掘削孔１１を設ける。掘削孔１１の上
部にはパイプ１３を立て、パイプ１３と掘削孔１１の内
部に水１４の装填されたゴムチューブ１５を設置する。
なお、ゴムチューブ１５内の水位は地盤１の表面より高
くし、掘削孔１１の内面を水圧によって押しつけるよう
に管理する。なお、ゴムチューブ１５内には水１４以外
の液体を装填してもよい。FIG. 2 is a longitudinal sectional view of the buffer 7, FIG. 3 is a sectional view taken along the line AA of FIG. 2, and FIG. 4 is a sectional view taken along the line BB of FIG. When constructing the buffer 7, first, the inside of the ground 1 is drilled with an auger or the like, and an excavation hole 11 is provided. A pipe 13 is erected on the top of the borehole 11, and a rubber tube 15 loaded with water 14 is installed inside the pipe 13 and the borehole 11.
The water level in the rubber tube 15 is set higher than the surface of the ground 1, and the inner surface of the excavation hole 11 is controlled so as to be pressed by water pressure. Note that a liquid other than the water 14 may be loaded into the rubber tube 15.
【００１４】図１において、例えばＳＣＰ工法を行う場
合、隣接地４との間に緩衝体７を必要本数だけ築造し、
その後サンドコンパクションパイル９を構築してＳＣＰ
工法を行う。ＳＣＰ工法が行われる際には、ゴムチュー
ブ１５内の水圧によって掘削孔１１の壁面の崩壊が防止
される。またゴムチューブ１５が変形することによって
ＳＣＰ工法による地盤の変形の隣接地４への伝達が防止
され、ゴムチューブ１５内の水１４が振動を吸収するた
め、隣接地４への振動の伝達が防止される。In FIG. 1, for example, when the SCP method is performed, a required number of buffers 7 are constructed between the adjacent land 4 and
After that, the sand compaction pile 9 is constructed and SCP
Perform the construction method. When the SCP method is performed, collapse of the wall surface of the excavation hole 11 is prevented by the water pressure in the rubber tube 15. In addition, the deformation of the rubber tube 15 prevents the ground deformation by the SCP method from being transmitted to the adjacent ground 4, and the water 14 in the rubber tube 15 absorbs the vibration, thereby preventing the vibration from being transmitted to the adjacent ground 4. Is done.
【００１５】ＳＣＰの工事が終わった時点で、ゴムチュ
ーブ１５内にモルタルを流し込みつつ、水１４を排水
し、掘削孔１１を閉じる。このように、第１の実施の形
態によれば、ＳＣＰ工法を用いても隣接地４への地盤の
変位や振動の伝達を防止することができる。このため都
市部においても安価なＳＣＰ工法を用いて地盤改良を行
うことができる。When the SCP is completed, the water 14 is drained while the mortar is poured into the rubber tube 15, and the borehole 11 is closed. As described above, according to the first embodiment, even if the SCP method is used, the displacement of the ground and the transmission of vibration to the adjacent ground 4 can be prevented. For this reason, ground improvement can be performed even in an urban area using an inexpensive SCP method.
【００１６】次に、第２の実施の形態について説明す
る。図５は、第２の実施の形態に係る地盤改良工法の概
要図である。図２において１は地盤、３は地下水面、９
はサンドコンパクションパイルであり、ＳＣＰ工法が用
いられる場所と隣接地１８との間に緩衝帯１９が設けら
れ、緩衝帯１９内に緩衝体２１が設けられる。Next, a second embodiment will be described. FIG. 5 is a schematic diagram of the ground improvement method according to the second embodiment. In FIG. 2, 1 is the ground, 3 is the groundwater table, 9
Is a sand compaction pile, in which a buffer band 19 is provided between a place where the SCP method is used and an adjacent land 18, and a buffer 21 is provided in the buffer band 19.
【００１７】図６は緩衝体２１の縦断面図、図７は図６
のＣ−Ｃによる断面図である。緩衝体２１を構築する場
合、まず地盤１内をオーガー等で削孔し、掘削孔２３を
設ける。掘削孔２３内に中央部に孔２７を有する円筒状
のクッション材２５を立て込む。クッション材２５はあ
る程度の剛性を有し、掘削孔２３の周辺の土の流入を防
止できるものであり、合成樹脂の繊維をカールさせたも
のを溶着整形したもの（ヘチマロン（商標名）等）の外
周部をシートで覆ったものなどである。FIG. 6 is a longitudinal sectional view of the buffer 21 and FIG.
It is sectional drawing by CC of FIG. When constructing the buffer 21, first, the inside of the ground 1 is drilled with an auger or the like, and an excavation hole 23 is provided. A cylindrical cushion material 25 having a hole 27 at the center is set in the excavation hole 23. The cushion material 25 has a certain degree of rigidity and can prevent the inflow of soil around the excavation hole 23. The cushion material 25 is formed by welding and shaping a material obtained by curling a synthetic resin fiber (such as Hetimaron (trade name)). For example, the outer peripheral portion is covered with a sheet.
【００１８】図５において、例えばＳＣＰ工法を行う場
合、隣接地１８との間に緩衝体２１を必要本数だけ築造
し、その後サンドコンパクションパイル９を構築してＳ
ＣＰ工法を行う。In FIG. 5, for example, when the SCP method is performed, the required number of buffers 21 are built between the ground 18 and the adjacent land 18, and then the sand compaction pile 9 is built to form
Perform the CP method.
【００１９】ＳＣＰ工法が行われる際には、クッション
材２５が弾性的な挙動を行い、掘削孔２３の周辺の土が
落ち込まないことから弾性材としての挙動を長期間保持
できる。地盤１内に必要本数の緩衝体２１を設置するこ
とによって、ＳＣＰ工法による隣接地１８への地盤の変
形、振動の伝達を低減させることができる。When the SCP method is performed, the cushion material 25 behaves elastically, and the soil around the excavation hole 23 does not fall, so that the behavior as an elastic material can be maintained for a long time. By installing the required number of buffers 21 in the ground 1, deformation of the ground and transmission of vibration to the adjacent ground 18 by the SCP method can be reduced.
【００２０】工事終了後は図６に示すように、クッショ
ン材２５の中央部に設けられた孔２７内にグラウトホー
ス２９を挿入して、グラウトホース２９からモルタルを
注入し、掘削孔２３を閉塞する。第２の実施の形態によ
れば、第１の実施の形態と同様に、ＳＣＰ工法を用いて
も隣接地１８への地盤の変位や振動の伝達を防止するこ
とができる。After the completion of the construction, as shown in FIG. 6, a grout hose 29 is inserted into a hole 27 provided at the center of the cushion material 25, mortar is injected from the grout hose 29, and the excavation hole 23 is closed. I do. According to the second embodiment, similarly to the first embodiment, even if the SCP method is used, the displacement of the ground and the transmission of vibration to the adjacent ground 18 can be prevented.
【００２１】[0021]
【発明の効果】以上、詳細に説明したように本発明によ
れば、コストが安く、隣接地への振動、変位の伝達が抑
制される地盤改良工法を提供することができる。As described above in detail, according to the present invention, it is possible to provide a ground improvement method which is inexpensive and suppresses transmission of vibration and displacement to an adjacent land.
【図１】 第１の実施の形態に係る地盤改良工法の概要
図FIG. 1 is a schematic diagram of a ground improvement method according to a first embodiment.
【図２】 緩衝体７の縦断面図FIG. 2 is a longitudinal sectional view of a buffer body 7;
【図３】 図２のＡ−Ａによる断面図FIG. 3 is a sectional view along AA in FIG. 2;
【図４】 図２のＢ−Ｂによる断面図FIG. 4 is a sectional view taken along line BB of FIG. 2;
【図５】 第２の実施の形態に係る地盤改良工法の概要
図FIG. 5 is a schematic diagram of a ground improvement method according to a second embodiment.
【図６】 緩衝体２１の縦断面図FIG. 6 is a longitudinal sectional view of the buffer 21.
【図７】 図６のＣ−Ｃによる断面図FIG. 7 is a sectional view taken along the line CC of FIG. 6;
【図８】 ＳＣＰ工法の概要図Fig. 8 Schematic diagram of SCP method
【図９】 緩衝溝１１１を設けてＳＣＰ工法を行う場合
の概要図FIG. 9 is a schematic diagram of a case where an SCP method is performed by providing a buffer groove 111;
【図１０】 緩衝パイプ１１３を設けてＳＣＰ工法を行
う場合の概要図FIG. 10 is a schematic diagram of a case where an SCP method is performed by providing a buffer pipe 113;
１………地盤 ７………緩衝体 ９………サンドコンパクションパイル １１………掘削孔 １３………パイプ １４………水 １５………ゴムチューブ ２１………緩衝体 ２５………クッション材 DESCRIPTION OF SYMBOLS 1 ... Ground 7 ... Buffer body 9 ... Sand compaction pile 11 ... Drilling hole 13 ... Pipe 14 ... Water 15 ... Rubber tube 21 ... Buffer body 25 ... Cushioning material
Claims (2)
孔を設け、該掘削孔の上部にパイプを立て、該パイプ及
び該掘削孔内部に液体を装填したゴムチューブを設置す
る工程と、 地盤改良を行う地盤内に砂杭を振動させつつ構築する工
程と、前記ゴムチューブ内にモルタルを流し込みつつ、前記液
体を排出して、前記掘削孔を閉じる工程と、 を具備することを特徴とする地盤改良工法。1. A plurality of excavation holes are provided around the ground on which ground improvement is to be performed , and a pipe is erected above the excavation holes.
A step of placing a rubber tube loaded with liquid inside micro該掘boring, a step of constructing while vibrating the Sunakui in soil to perform ground improvement, while pouring mortar into the rubber tube, the liquid
Discharging the body and closing the excavation hole .
孔を設け、該掘削孔内部に中央部に孔を有する円筒状の
クッション材を設ける工程と、 地盤改良を行う地盤内に砂杭を振動させつつ構築する工
程と、前記クッション材の中央の孔を用いてモルタルを注入
し、前記掘削孔を閉じる工程と、 を具備することを特徴とする地盤改良工法。2. A step of providing a plurality of excavation holes around the ground for which the ground improvement is to be performed, and providing a cylindrical cushion material having a hole at a central portion inside the excavation hole; Building a sand pile inside while vibrating, and injecting mortar using the center hole of the cushion material
And closing the excavation hole .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28135695A JP2905129B2 (en) | 1995-10-30 | 1995-10-30 | Ground improvement method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28135695A JP2905129B2 (en) | 1995-10-30 | 1995-10-30 | Ground improvement method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09125359A JPH09125359A (en) | 1997-05-13 |
| JP2905129B2 true JP2905129B2 (en) | 1999-06-14 |
Family
ID=17637977
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28135695A Expired - Fee Related JP2905129B2 (en) | 1995-10-30 | 1995-10-30 | Ground improvement method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2905129B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106703004A (en) * | 2017-03-14 | 2017-05-24 | 王继忠 | Treatment method for collapsible loess foundation |
| CN107130614A (en) * | 2017-05-31 | 2017-09-05 | 中铁二十局集团第六工程有限公司 | The anti-Landslide System of swelled ground high slope and construction method |
| JP7098250B2 (en) * | 2018-10-30 | 2022-07-11 | 株式会社不動テトラ | Ground displacement suppression method |
-
1995
- 1995-10-30 JP JP28135695A patent/JP2905129B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09125359A (en) | 1997-05-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2905129B2 (en) | Ground improvement method | |
| JP3714395B2 (en) | Reinforcement method for the ground below existing structures | |
| JPH02232416A (en) | Foundation pile structure | |
| JP4339803B2 (en) | Anti-vibration pile, anti-vibration wall using the same and construction method thereof | |
| JPH05125726A (en) | Construction of pile with drain layer | |
| JP2790038B2 (en) | Reinforcement method of existing pile foundation building | |
| JPS63110319A (en) | Stabilization work of banking | |
| JP3494727B2 (en) | Liquefaction countermeasures | |
| JP2001271347A (en) | Drop method for ready-made pile | |
| JPH0768707B2 (en) | Open caisson method | |
| JPH03140594A (en) | Construction work of water-stopping shaft | |
| JP3726991B2 (en) | Construction method of bearing capacity improvement pile | |
| JPH0351415A (en) | Constructing method for underground continuous wall | |
| JPS59224723A (en) | Breaking and cutting of concrete | |
| JPH0328416A (en) | Construction method to build up pile | |
| JPH06220841A (en) | Construction method for continuous underground wall using steel pipe pile | |
| JP2512157B2 (en) | Reinforcement method for soft ground | |
| JPH0266220A (en) | Prevention method of damage at cross-section in concrete part of cast-in-place pile | |
| JPS6142044B2 (en) | ||
| JPS61151318A (en) | Method of elimianting negative friction force of cast-in-place pile | |
| JPS62248711A (en) | Formation of pile using cloth cylinder coated with rubbery paint | |
| JPH0215692B2 (en) | ||
| JPH01203515A (en) | Earthquake-proof pile and its construction | |
| JPH04293818A (en) | Rotary instrusive steel tube pile construction method | |
| JPS59130916A (en) | Buried piling work |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |