【０００１】
【発明の属する技術分野】
本発明は鋼管杭の打設方法に関し、詳しくは打設時の振動，騒音を低減する技術に関する。
【０００２】
【従来の技術】
従来、鋼管杭の打設方法としては、鋼管杭の先端部に底板を一体的に溶接接合し、同鋼管杭を予備的に掘削した削孔内に建て込み、鋼管杭の内径よりやや細い外径のハンマーで鋼管杭の内部から打撃する技術が提案されている（例えば特許文献１参照）。
【０００３】
この技術によれば、ハンマーの打撃が鋼管杭内で行われるから、杭頭を地上で直打する従来工法と比較して低振動，低騒音で打設できる。しかしながら、鋼管杭が地上にある打設初期の段階では打撃の反響音が外部に漏れ易く、遮音が不充分となる問題があった。
【０００４】
【特許文献１】
特開平８−２９１５１９号公報
【０００５】
【発明が解決しようとする課題】
本発明が解決しようとする課題は、従来のこれらの問題点を解消し、打設終始に渡って低振動，低騒音で鋼管杭を地盤へ埋設できる鋼管杭の打設方法を提供することにある。
【０００６】
【課題を解決するための手段】
かかる課題を解決した本発明の構成は、
１） 先端に掘削刃を備えた中空の鋼管杭の内底部に受圧板を設け、同鋼管杭を地盤に回転圧入して掘削刃で掘削しながら先端部が地盤の支持層に達する深さまで埋入し、その後鋼管杭の内径より小さい径の外径を有する大重量のハンマーを鋼管杭内に吊り下げ、同ハンマーを鋼管杭内の底部で落下と引き上げを繰り返してハンマーで受圧板を打撃し、その打撃力で鋼管杭の先端部を地盤の支持層に埋入し、鋼管杭を低振動低騒音で打設できるようにしたことを特徴とする鋼管杭の打設方法
２） 鋼管杭の掘削刃がスクリューに複数のビットを突設したものである前記１）記載の鋼管杭の打設方法
３） 打撃時にハンマーの吊り下げ部材が挿通可能なカバー体を鋼管杭の上端開口部に脱着自在に装着し、打撃音をより低減できるようにした前記１）又は２）記載の鋼管杭の打設方法
４） カバー体の外面に目盛りを設け、同目盛りで鋼管杭の沈下量及びリバウンド量を計測する計測器を地表に設置した前記１）〜３）いずれか記載の鋼管杭の打設方法
５） 地中に打設された鋼管杭内にコンクリートを流し込んで硬化させる前記１）〜４）いずれか記載の鋼管杭の打設方法
にある。
【０００７】
【作用】
本発明によれば、補強すべき地盤へ鋼管杭をその主要部分が地盤内へ埋入されるまで回転圧入した後、鋼管杭内で打撃するから、打撃の反響音が外部へ漏れ難く、しかも打撃時間を短縮でき、従来と比較してより低振動，低騒音で打設が行えるようになる。
【０００８】
【発明の実施の形態】
本発明で用いる鋼管杭の先端には掘削刃が溶接等により取り付けられ、その掘削刃としてはスクリューに複数のビットを突設したものが一般的であるが、その他地盤を掘削できる刃状のものであれば採用できる。また、打撃時にハンマーの吊り下げ部材が挿通可能なカバー体を鋼管杭の上端開口部に脱着自在に装着すると、打撃音をより低減できて好ましい。
【０００９】
さらに、カバー体の外面に目盛りを設け、同目盛りで鋼管杭の上下変動量を計測する計測器を地表に設置すると、鋼管杭の沈下量及びリバウンド量できる。なお、鋼管杭を地中に打設後は必要に応じて鋼管杭内にコンクリートを流し込んで硬化させることもある。以下、本発明の実施例を図面に基づいて具体的に説明する。
【００１０】
【実施例】
図１は実施例の鋼管杭の縦断面図、図２は実施例の掘削刃の分解斜視図、図３，４は実施例の鋼管杭の打設工程を示す説明図である。図中、１は鋼管杭、２は掘削刃、２ａはビット、２ｂは筒体、２ｃは円盤、２ｄは羽根、３は受圧板、３ａは筒体、４は掛止突起、５は接続部、６は回転圧入装置、７はハンマー、８はワイヤー、９はクレーン、１０はカバー体、１０ａは挿通孔、１０ｂは目盛り、１１は計測器、Ｇは地盤、Ｇａは支持層である。
【００１１】
本実施例の鋼管杭１は、図１，２に示すように長さ３ｍ、外径４０ｃｍの鋼管で構成され、底面に受圧板３を溶接した筒体３ａを鋼管の先端に挿着し、同筒体３ａの外周に羽根２ｄを取り付け、筒体３ａの下面に円盤２ｃを固着した径の異なる各筒体２ｂを段状に取り付け、各円盤２ｃ及び受圧板３に複数のビット２ａを取り付け、外面上部に鋼管杭１を回転圧入する回転圧入装置６の接続部５と掛止する掛止突起４を設けている。
【００１２】
また、鋼管杭１の上端部にはハンマー７を吊り下げるワイヤー８が挿通可能な小径の挿通孔１０ａが形成されたカバー体１０を脱着自在に取り付けできるようにしている。そのカバー体１０の外面には、計測器１１の計測針で鋼管杭１の沈下量やリバウンド量を計測するための目盛り１０ｂを刻設している。
【００１３】
本実施例では、図３（ａ）に示すように回転圧入装置６の接続部５を鋼管杭１の掛止突起４に掛止して杭打ちすべき地盤Ｇの上方で吊設し、回転圧入装置６を駆動させて鋼管杭１がほぼ地盤Ｇ内に埋入される深さまで回転圧入して先端の掘削刃２で地盤Ｇを掘削しながら貫入する。
【００１４】
次に、接続部５を取り外して図３（ｂ）に示すようにワイヤー８をカバー体１０の挿通孔１０ａに挿通させてハンマー７に連結した後、同ハンマー７を鋼管杭１内に吊り下げてカバー体１０を鋼管杭１の上端部に装着するとともにカバー体１０近傍の地表計測器１１を設置する。そして図４（ａ）に示すようにクレーン９を上げ下げしてハンマー７を鋼管杭１内で落下及び引き上げを繰り返して受圧板３を打撃し、その打撃力で図４（ｂ）に示すように鋼管杭１の下部を地盤Ｇの支持層Ｇａに貫入して埋設する。
【００１５】
本実施例はこのように構成したから、打撃工程が地中で行われることにより、打撃の反響音が外部へ漏れ難く、しかも回転圧入する分打撃時間が著しく短縮され、従来と比較してより低振動，低騒音で打設が行えるようになる。また、回転圧入を主体とし打撃回数を少なくしたから地盤への直進性に優れ、打撃のみと比較して精度良く鋼管杭を埋設できる。
【００１６】
【発明の効果】
以上説明したように、本発明によれば打設終始に渡って低振動，低騒音で鋼管杭を地盤へ埋設し得る鋼管杭の打設方法を提供できる。
【図面の簡単な説明】
【図１】実施例の鋼管杭の縦断面図である。
【図２】実施例の掘削刃の分解斜視図である。
【図３】実施例の鋼管杭の打設工程を示す説明図である。
【図４】実施例の鋼管杭の打設工程を示す説明図である。
【符号の説明】
１ 鋼管杭
２ 掘削刃
２ａ ビット
２ｂ 筒体
２ｃ 円盤
２ｄ 羽根
３ 受圧板
３ａ 筒体
４ 掛止突起
５ 接続部
６ 回転圧入装置
７ ハンマー
８ ワイヤー
９ クレーン
１０ カバー体
１０ａ 挿通孔
１０ｂ 目盛り
１１ 計測器
Ｇ 地盤
Ｇａ 支持層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for driving a steel pipe pile, and more particularly to a technique for reducing vibration and noise during driving.
[0002]
[Prior art]
Conventionally, as a method of placing steel pipe piles, a bottom plate is integrally welded to the tip of the steel pipe pile, and the steel pipe pile is built in a pre-drilled hole, and the outer diameter is slightly smaller than the inner diameter of the steel pipe pile. A technique of hitting the inside of a steel pipe pile with a hammer having a diameter has been proposed (for example, see Patent Document 1).
[0003]
According to this technique, since the hammer is hit in the steel pipe pile, it can be driven with lower vibration and lower noise than the conventional method of directly hitting the pile head on the ground. However, in the early stage of casting when the steel pipe pile is on the ground, there is a problem that the reverberation sound of the blow is likely to leak to the outside and the sound insulation is insufficient.
[0004]
[Patent Document 1]
JP-A-8-291519
[Problems to be solved by the invention]
The problem to be solved by the present invention is to solve these conventional problems and to provide a method of driving steel pipe piles that can be buried in the ground with low vibration and low noise throughout the driving. is there.
[0006]
[Means for Solving the Problems]
The configuration of the present invention that has solved such a problem includes:
1) A pressure-receiving plate is provided at the inner bottom of a hollow steel pipe pile with a drilling tip at the tip, and the steel pipe pile is rotationally pressed into the ground and excavated with a drilling blade while the tip is buried to a depth reaching the ground support layer. After that, a heavy hammer with an outer diameter smaller than the inner diameter of the steel pipe pile is suspended in the steel pipe pile, and the hammer is repeatedly dropped and raised at the bottom of the steel pipe pile, and the pressure receiving plate is hit with the hammer. The impact of the impact force, the tip of the steel pipe pile is buried in the support layer of the ground so that the steel pipe pile can be driven with low vibration and low noise. The method for setting a steel pipe pile according to the above 1), wherein the excavating blade has a plurality of bits protruding from a screw 3) A cover body through which a hanging member of a hammer can be inserted at the time of hitting is detached from an upper end opening of the steel pipe pile. The above-mentioned 1 which is freely mounted so that the impact sound can be further reduced. Or 2) the method of placing a steel pipe pile according to the above 4) a scale is provided on the outer surface of the cover body, and a measuring instrument for measuring the amount of settlement and rebound of the steel pipe pile is installed on the surface with the scale, any of the above 1) to 3) 5) The method for placing a steel pipe pile according to any one of the above 1) to 4), wherein concrete is poured into the steel pipe pile placed in the ground and hardened.
[0007]
[Action]
According to the present invention, the steel pipe pile is rotationally press-fitted into the ground to be reinforced until its main part is buried in the ground, and is hit in the steel pipe pile. The hitting time can be shortened, and the driving can be performed with lower vibration and lower noise than before.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
An excavation blade is attached to the tip of the steel pipe pile used in the present invention by welding or the like, and the excavation blade is generally formed by projecting a plurality of bits on a screw. If it can be adopted. In addition, it is preferable that a cover body through which the hanging member of the hammer can be inserted at the time of impact be detachably attached to the upper end opening of the steel pipe pile, because the impact sound can be further reduced.
[0009]
Further, when a scale is provided on the outer surface of the cover body and a measuring instrument for measuring the vertical fluctuation amount of the steel pipe pile is installed on the ground at the same scale, the sinking amount and the rebound amount of the steel pipe pile can be obtained. After the steel pipe pile is driven into the ground, concrete may be poured into the steel pipe pile and hardened as necessary. Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
[0010]
【Example】
FIG. 1 is a longitudinal sectional view of a steel pipe pile according to an embodiment, FIG. 2 is an exploded perspective view of a drilling blade according to the embodiment, and FIGS. In the drawing, 1 is a steel pipe pile, 2 is a drilling blade, 2a is a bit, 2b is a cylinder, 2c is a disk, 2d is a blade, 3 is a pressure receiving plate, 3a is a cylinder, 4 is a latching projection, and 5 is a connecting portion. , 6 is a rotary press-fitting device, 7 is a hammer, 8 is a wire, 9 is a crane, 10 is a cover, 10a is an insertion hole, 10b is a scale, 11 is a measuring instrument, G is ground, and Ga is a support layer.
[0011]
The steel pipe pile 1 of the present embodiment is composed of a steel pipe having a length of 3 m and an outer diameter of 40 cm as shown in FIGS. 1 and 2, and a cylindrical body 3 a having a pressure receiving plate 3 welded to a bottom surface is inserted into a tip of the steel pipe. The blades 2d are mounted on the outer periphery of the cylindrical body 3a, the cylindrical bodies 2b having different diameters to which the disks 2c are fixed are mounted in a stepped manner on the lower surface of the cylindrical body 3a, and the plurality of bits 2a are mounted on the disks 2c and the pressure receiving plate 3. On the upper part of the outer surface, a hooking projection 4 for hooking with the connecting portion 5 of the rotary press-fitting device 6 for rotary-pressing the steel pipe pile 1 is provided.
[0012]
A cover body 10 having a small-diameter insertion hole 10a through which a wire 8 for suspending a hammer 7 can be inserted can be detachably attached to the upper end of the steel pipe pile 1. On the outer surface of the cover body 10, a scale 10b for measuring the amount of settlement or rebound of the steel pipe pile 1 with a measuring needle of a measuring device 11 is engraved.
[0013]
In this embodiment, as shown in FIG. 3A, the connecting portion 5 of the rotary press-fitting device 6 is hung on the hooking projection 4 of the steel pipe pile 1 and suspended above the ground G to be piled, and is rotated. The press-fitting device 6 is driven to rotate and press-fit the steel pipe pile 1 to a depth substantially embedded in the ground G, and the steel pipe pile 1 penetrates while excavating the ground G with the excavating blade 2 at the tip.
[0014]
Next, as shown in FIG. 3 (b), the connecting portion 5 is removed and the wire 8 is inserted through the insertion hole 10 a of the cover body 10 and connected to the hammer 7, and the hammer 7 is suspended in the steel pipe pile 1. Then, the cover body 10 is mounted on the upper end of the steel pipe pile 1 and the ground surface measuring instrument 11 near the cover body 10 is installed. Then, as shown in FIG. 4A, the crane 9 is raised and lowered, and the hammer 7 is repeatedly dropped and raised in the steel pipe pile 1 to strike the pressure receiving plate 3, and as shown in FIG. The lower part of the steel pipe pile 1 penetrates the support layer Ga of the ground G and is buried.
[0015]
Since the present embodiment is configured as described above, the impact process is performed in the ground, so that the reverberation sound of the impact is hardly leaked to the outside, and the impact time due to the rotary press-fitting is significantly reduced. Pouring can be performed with low vibration and low noise. In addition, since the number of impacts is reduced mainly by rotary press-fitting, the straightness to the ground is excellent, and the steel pipe pile can be buried with higher accuracy than the impact alone.
[0016]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a method of driving a steel pipe pile which can bury the steel pipe pile in the ground with low vibration and low noise throughout the driving.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a steel pipe pile according to an embodiment.
FIG. 2 is an exploded perspective view of the excavation blade of the embodiment.
FIG. 3 is an explanatory view showing a step of driving a steel pipe pile according to the embodiment.
FIG. 4 is an explanatory view showing a step of driving a steel pipe pile according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steel pipe pile 2 Drilling blade 2a Bit 2b Cylindrical body 2c Disk 2d Blade 3 Pressure receiving plate 3a Cylindrical body 4 Hanging projection 5 Connecting portion 6 Rotary press-fitting device 7 Hammer 8 Wire 9 Crane 10 Cover body 10a Insertion hole 10b Scale 11 Measuring instrument G Ground Ga support layer
