JPH0796784B2 - Caisson method - Google Patents
Caisson methodInfo
- Publication number
- JPH0796784B2 JPH0796784B2 JP63247517A JP24751788A JPH0796784B2 JP H0796784 B2 JPH0796784 B2 JP H0796784B2 JP 63247517 A JP63247517 A JP 63247517A JP 24751788 A JP24751788 A JP 24751788A JP H0796784 B2 JPH0796784 B2 JP H0796784B2
- Authority
- JP
- Japan
- Prior art keywords
- caisson
- ground
- bubbles
- water
- mixed layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title claims description 25
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 26
- 238000005187 foaming Methods 0.000 claims description 5
- 239000004088 foaming agent Substances 0.000 claims description 5
- 239000007788 liquid Substances 0.000 claims description 2
- 230000002093 peripheral effect Effects 0.000 description 14
- 238000002347 injection Methods 0.000 description 7
- 239000007924 injection Substances 0.000 description 7
- 238000010276 construction Methods 0.000 description 5
- 230000001603 reducing effect Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 230000001050 lubricating effect Effects 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 2
- 229910000278 bentonite Inorganic materials 0.000 description 2
- 239000000440 bentonite Substances 0.000 description 2
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 239000008257 shaving cream Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
Landscapes
- Revetment (AREA)
Description
【発明の詳細な説明】 《産業上の利用分野》 この発明は、ケーソン工法におけるケーソンの周面摩擦
を低減する方法に関する。TECHNICAL FIELD The present invention relates to a method for reducing the friction of the caisson surface in a caisson method.
《従来の技術》 周知のように、橋脚などの基礎の構築工法の一種として
ケーソン工法があり、この工法では、筒状ないしは箱状
の構造物を地盤中の支持層まで沈設し、荷重を地盤に伝
達させる。<Prior art> As is well known, there is a caisson method as one of the construction methods for foundations such as piers. In this method, a cylindrical or box-like structure is sunk to the support layer in the ground, and the load is applied to the ground. To be transmitted to.
この種のケーソン工法は、オープンケーソン工法とニュ
ーマチックケーソン工法とに大別され、一般的には、ケ
ーソン先端の地盤を掘削したときに、その自重だけで沈
下させることが難しいので、水，土砂，鋼材等の荷重を
載荷することで沈設される。This type of caisson method is roughly divided into an open caisson method and a pneumatic caisson method. Generally, when excavating the ground at the tip of the caisson, it is difficult to settle down due to its own weight. , It is sunk by loading the load such as steel.
ところで、このようなケーソン工法では、沈設途中でケ
ーソンの外周面と地盤との周面摩擦が過大になって、荷
重を載荷してもその沈設ができない状態が発生する。By the way, in such a caisson construction method, the peripheral surface friction between the outer peripheral surface of the caisson and the ground becomes excessive during the submersion, so that the subsidence cannot occur even if a load is applied.
このような状態が発生したときに、従来、ケーソンの外
周面と地盤との間に空気あるいは水をジェット噴射させ
る方法、ベントナイトを注入する方法が採用されてい
た。When such a state occurs, conventionally, a method of jetting air or water between the outer peripheral surface of the caisson and the ground and a method of injecting bentonite have been adopted.
しかしながら、このような周面摩擦低減方法にいずれも
以下に説明する技術的課題があった。However, all of these methods of reducing the peripheral friction have the technical problems described below.
《発明が解決しようとする課題》 すなわち、前者の方法では、ケーソンの側壁に予め配管
を設けておき、この配管を介して空気あるいは水をジェ
ット噴射させるが、空気を噴射する方法では効果を比較
的長時間維持させることができないという問題などがあ
る。<< Problems to be Solved by the Invention >> That is, in the former method, a pipe is provided in advance on the side wall of the caisson, and air or water is jetted through this pipe. However, in the method of jetting air, the effects are compared. There is a problem that it cannot be maintained for a long time.
また、水を噴射する方法では、噴射された水が地盤中に
浸透して、噴射後に水締めが発生し、かえって摩擦力が
大きくなるという問題があり、特に、人工島の中詰土中
にケーソンを沈設する場合は中詰土が緩いため水締めが
容易に発生し、その影響が顕著に現れる。In addition, in the method of injecting water, there is a problem that the injected water penetrates into the ground, water tightening occurs after the injection, and the frictional force becomes rather large. When the caisson is sunk, since the filling soil is loose, water tightening easily occurs, and the effect becomes remarkable.
さらに、後者の方法では、ケーソンを沈設した後にその
外周面と地盤との間にベントナイトが残留するので、施
工後に周面摩擦力が回復せず、ケーソンの安定に悪影響
を及ぼすという問題があった。Furthermore, in the latter method, since bentonite remains between the outer peripheral surface of the caisson and the ground after the caisson is sunk, there is a problem in that the peripheral frictional force cannot be recovered after construction and the stability of the caisson is adversely affected. .
この発明はこのような従来の問題点に鑑みてなされたも
のであって、その目的とするところは、水締めを発生さ
せることなく比較的長期間摩擦低減効果が得られるとと
もに、沈設後に簡単に周面摩擦力が回復できるケーソン
工法を提供することにある。The present invention has been made in view of such conventional problems, and an object thereof is to obtain a friction reducing effect for a relatively long period of time without causing water tightening, and to easily perform after depositing. It is to provide a caisson method capable of recovering the circumferential frictional force.
《問題点を解決するための手段》 上記目的を達成するために、この発明は、ケーソンを地
盤中に沈設する際に、ケーソン外周の地盤中に起泡剤を
含む液体を発泡させて生じる気泡をジェット水とともに
高圧噴射して、前記気泡とケーソン外周の地盤とを撹乱
混合することにより、地盤に前記気泡が混在してなる混
在層をケーソンの外周に形成しつつケーソンを沈設して
行くことを特徴とする。<< Means for Solving the Problems >> In order to achieve the above-mentioned object, the present invention is directed to foaming a liquid containing a foaming agent in the ground around the caisson when the caisson is submerged in the ground. By high-pressure jetting of water with jet water to disturb the bubbles and the ground around the caisson, the caisson is sunk while forming a mixed layer in which the bubbles are mixed in the ground on the outer circumference of the caisson. Is characterized by.
《作用》 上記構成のケーソン工法によれば、ケーソンの外周面と
接している地盤中に気泡をジェット水とともに高圧噴射
して地盤に気泡が混在した混在層を形成するので、混在
層中の気泡の潤滑作用により、沈設中におけるケーソン
外周面と地盤との間の摩擦力が低減する。<Operation> According to the caisson method with the above configuration, since bubbles are mixed with jet water at high pressure in the ground in contact with the outer surface of the caisson to form a mixed layer in which bubbles are mixed, the bubbles in the mixed layer are formed. The lubricating action of reduces the frictional force between the outer surface of the caisson and the ground during the sinking.
また、混在層中に混在させられた気泡は、比較的長時間
その状態が維持されるとともに、ケーソンの沈設後これ
が消滅すると、外周の地盤はそのままの位置で土砂単独
の地盤となることにより、ケーソン外周面との間の摩擦
力を回復する。In addition, the air bubbles mixed in the mixed layer are maintained for a relatively long time, and when this disappears after the caisson is sunk, the ground on the outer periphery becomes the ground of the soil alone in the same position, It recovers the frictional force between the outer surface of the caisson.
《実施例》 以下、この発明の好適な実施例について添付図面を参照
にして詳細に説明する。<Example> Hereinafter, a preferred example of the present invention will be described in detail with reference to the accompanying drawings.
第１図はこの発明にかかるケーソン工法の一実施例を示
している。FIG. 1 shows an embodiment of the caisson method according to the present invention.
同図に示す工法は、この発明をオープンケーソンに適用
した場合を例示しており、ケーソン10は鉄筋コンクリー
ト製であって、下端の刃口部12と、その上部に形成され
た本体部14とから構成されている。The construction method shown in the figure illustrates the case where the present invention is applied to an open caisson.The caisson 10 is made of reinforced concrete, and includes a blade opening 12 at the lower end and a main body 14 formed on the upper portion thereof. It is configured.
本体部14は刃口部12の外径よりも小さくなっていて、こ
れらの接続部分に段差部16が形成され、刃口部12の沈下
により本体部14の外周面と周辺地盤との間に間隙を形成
し、本体部14の周面摩擦を低減させるためのフリクショ
ンカット部が形成されるようになっている。The main body portion 14 is smaller than the outer diameter of the blade opening portion 12, a step portion 16 is formed at these connecting portions, and due to the sinking of the blade opening portion 12 between the outer peripheral surface of the main body portion 14 and the surrounding ground. A friction cut portion for forming a gap and reducing friction on the peripheral surface of the main body portion 14 is formed.
本体部14内には、縦方向に沿って延びる一対で１組とな
るジェット水供給通路および気泡供給通路20,22が周方
向に間隔を置いて、例えば、パイプを埋設する方法など
によって形成されている。In the main body portion 14, a pair of jet water supply passages and bubble supply passages 20 and 22 extending in the vertical direction are formed at intervals in the circumferential direction, for example, by a method of burying a pipe or the like. ing.
そして、ジェット水供給通路20の上端には、水タンク24
に収容された水を加圧するポンプ26が接続されるととも
に、気泡供給通路22の上端には、発泡器28が接続されて
いる。At the upper end of the jet water supply passage 20, a water tank 24
A pump 26 for pressurizing the water stored in is connected with a foaming device 28 at the upper end of the bubble supply passage 22.
この発泡器28には、起泡剤水溶液、例えばタンパク系の
起泡剤や界面活性剤を水に溶解したものが供給されると
ともに、この起泡剤水溶液をシェービングクリーム状に
発泡させるエアコンプレッサ30が設置されている。The foaming device 28 is supplied with a foaming agent aqueous solution, for example, a protein-based foaming agent or a surfactant dissolved in water, and an air compressor 30 for foaming the foaming agent aqueous solution into a shaving cream. Is installed.
一方、上記ジェット水供給通路20と気泡供給通路22の下
端は、ケーソン10の段差部16に開口する噴射ノズル32に
それぞれ接続されている。On the other hand, the lower ends of the jet water supply passage 20 and the bubble supply passage 22 are respectively connected to the injection nozzles 32 that open to the step portion 16 of the caisson 10.
噴射ノズル32は、二重管から構成され、外周部にジェッ
ト水供給通路20が接続されるとともに、中心部に気泡供
給通路22が接続されており、気泡供給通路22を介して供
給されるシェービングクリーム状の気泡Ｂの外周を取り
囲むようにしてジェット水供給通路20からのジェット水
Ａがその先端から高圧噴射される。The injection nozzle 32 is composed of a double pipe, the jet water supply passage 20 is connected to the outer peripheral portion thereof, and the bubble supply passage 22 is connected to the central portion thereof, and the shaving is supplied through the bubble supply passage 22. The jet water A is jetted from the jet water supply passage 20 at high pressure so as to surround the outer periphery of the creamy bubble B.
ケーソン10を沈設するにあたり、噴射ノズル32を介し
て、気泡Ｂとジェット水Ａとが、ケーソン10の外周面に
接している地盤中に向けて高圧噴射される。When the caisson 10 is sunk, the bubbles B and the jet water A are jetted through the jet nozzle 32 at high pressure toward the ground contacting the outer peripheral surface of the caisson 10.
噴射ノズル32から上方に向けて高圧噴射された気泡Ｂ
は、ジェット水Ａに携行されて撹乱された地盤中に到達
し、その中に混在することにより、ケーソン10の外周に
は地盤と気泡との混在層18が形成される。Bubbles B that are high-pressure injected upward from the injection nozzle 32
Is carried in the jet water A and reaches the disturbed ground, and is mixed therein, so that a mixed layer 18 of the ground and bubbles is formed on the outer periphery of the caisson 10.
地盤中に気泡Ｂが混在させられると、その潤滑作用によ
り、ケーソン10の外周面とこれの外周の地盤すなわち混
在層18との間の摩擦力が低減するのでケーソン10を簡単
に沈下させることが可能になる。When the air bubbles B are mixed in the ground, the lubricating action reduces the frictional force between the outer peripheral surface of the caisson 10 and the ground on the outer circumference thereof, that is, the mixed layer 18, so that the caisson 10 can be easily submerged. It will be possible.
また、混在層18中に混在させられた気泡Ｂは、比較的長
時間その状態が維持されるとともに、ケーソンの沈下が
終了して所定時間経過後に気泡Ｂが消滅するとケーソン
10の外周面とこれの外周の地盤との間には、残留物がほ
とんどないので、摩擦力は元の状態にほぼ完全に回復す
る。Further, the bubble B mixed in the mixed layer 18 maintains its state for a comparatively long time, and when the bubble B disappears after a lapse of a predetermined time after the termination of the caisson, the caisson is terminated.
Since there is almost no residue between the outer peripheral surface of 10 and the ground around it, the frictional force is almost completely restored to the original state.
なお、上記実施例では、気泡Ｂとジェット水Ａとを噴射
ノズル32で混合して高圧噴射する方法を示したが、これ
らを別々のノズルで噴射しても良く、この場合には、気
泡Ｂをジェット水Ａの噴射前に高圧噴射する方が望まし
い。In the above embodiment, the method of mixing the bubble B and the jet water A by the injection nozzle 32 and performing high-pressure injection has been described, but they may be injected by separate nozzles. In this case, the bubble B It is desirable to inject high-pressure water before jetting water A.
また、本体部14は、予め製作したものを順次刃口部12上
に組み立てる方法と、現場でこれを構築する方法のいず
れでも良い。Further, the main body portion 14 may be either a method of sequentially assembling the prefabricated ones on the blade opening portion 12 or a method of constructing this on the spot.
さらに、噴射ノズル32の設置位置は、ケーソン10の段差
部16だけでなく、本体部14の外周面に設けておいても良
い。Furthermore, the injection nozzle 32 may be installed not only on the step portion 16 of the caisson 10 but also on the outer peripheral surface of the main body portion 14.
《発明の効果》 以上実施例で説明したように、この発明にかかるケーソ
ン工法によれば、ケーソンの沈設中は混在層に含まれる
気泡の潤滑作用によりケーソン外周面と混在層との摩擦
力を低減してケーソンの沈下をスムーズに行なわしめる
とともに、ケーソンの沈設後は混在層内の気泡が消滅す
ることによりケーソンとこれの外周の地盤との間の摩擦
力が回復して、沈設したケーソンを安定して機能させる
ことができる。<< Effects of the Invention >> As described in the above embodiments, according to the caisson method according to the present invention, the frictional force between the caisson outer peripheral surface and the mixed layer is increased by the lubricating action of the bubbles contained in the mixed layer during the caisson deposition. The caisson can be smoothly reduced by reducing it, and after the caisson is settled, the bubbles in the mixed layer disappear, so that the frictional force between the caisson and the ground around the caisson is restored, and the caisson is removed. It can function stably.
第１図は本発明方法の一実施例の施工状態を示す断面図
である。 10……ケーソン、12……刃口部 14……本体部、18……混在層 Ａ……ジェット水、Ｂ……気泡FIG. 1 is a sectional view showing a construction state of an embodiment of the method of the present invention. 10 …… Caison, 12 …… Blade part 14 …… Main body part, 18 …… Mixed layer A …… Jet water, B …… Bubbles
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭56−16733（ＪＰ，Ａ) 特開 昭49−27015（ＪＰ，Ａ) 特開 昭63−51528（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-56-16733 (JP, A) JP-A-49-27015 (JP, A) JP-A-63-51528 (JP, A)
Claims (1)
ン外周の地盤中に起泡剤を含む液体を発泡させて生じる
気泡をジェット水とともに高圧噴射して、前記気泡とケ
ーソン外周の地盤とを撹乱混合することにより、地盤に
前記気泡が混在してなる混在層をケーソンの外周に形成
しつつケーソンを沈設して行くことを特徴とするケーソ
ン工法。1. When the caisson is submerged in the ground, bubbles generated by foaming a liquid containing a foaming agent into the ground around the caisson are jetted together with jet water at high pressure, and the bubbles and the ground around the caisson are separated from each other. The caisson method is characterized in that the caisson is sunk while forming a mixed layer formed by mixing the bubbles in the ground on the outer periphery of the caisson by agitating and mixing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63247517A JPH0796784B2 (en) | 1988-10-03 | 1988-10-03 | Caisson method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63247517A JPH0796784B2 (en) | 1988-10-03 | 1988-10-03 | Caisson method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0296023A JPH0296023A (en) | 1990-04-06 |
| JPH0796784B2 true JPH0796784B2 (en) | 1995-10-18 |
Family
ID=17164662
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63247517A Expired - Lifetime JPH0796784B2 (en) | 1988-10-03 | 1988-10-03 | Caisson method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0796784B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03100231A (en) * | 1989-09-13 | 1991-04-25 | Shimizu Corp | caisson method |
| JP4886894B1 (en) * | 2010-12-06 | 2012-02-29 | 横浜ライト工業株式会社 | Method for extracting buried pile and foaming water generator |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4927015A (en) * | 1972-07-07 | 1974-03-11 | ||
| JPS5616733A (en) * | 1979-07-20 | 1981-02-18 | Takuo Mochizuki | Caisson method |
| JPS6351528A (en) * | 1986-08-22 | 1988-03-04 | Aoki Kensetsu:Kk | Settling work of caisson |
-
1988
- 1988-10-03 JP JP63247517A patent/JPH0796784B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0296023A (en) | 1990-04-06 |
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