JPH07216904A - Pneumatic caisson - Google Patents
Pneumatic caissonInfo
- Publication number
- JPH07216904A JPH07216904A JP1329994A JP1329994A JPH07216904A JP H07216904 A JPH07216904 A JP H07216904A JP 1329994 A JP1329994 A JP 1329994A JP 1329994 A JP1329994 A JP 1329994A JP H07216904 A JPH07216904 A JP H07216904A
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- box
- exhaust
- excavation work
- air
- 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.)
- Granted
Links
Landscapes
- Underground Structures, Protecting, Testing And Restoring Foundations (AREA)
- Earth Drilling (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、地下構造物、例えば橋
脚やビルディング等の基礎あるいは地下室等を、いわゆ
るニューマチックケーソン工法で構築する際に用いられ
る圧気ケーソンの改良に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a pneumatic caisson used when constructing an underground structure, for example, a foundation of a bridge pier or a building or a basement by a so-called pneumatic caisson method.
【０００２】[0002]
【従来の技術】いわゆるニューマチックケーソン工法で
は、図５に示すように、筒状をなす函体（20）の下部に
圧力隔壁（21）を水平配設して気密な掘削作業室（22）
が形成される。この掘削作業室（22）に、図示しない送
気管から圧縮空気を送気し、当該室内を地下水圧に対抗
し得る程度の高圧雰囲気に維持しながら地盤を人力若し
くは機械力で掘削することにより、圧気ケーソン（24）
をその自重で沈下させている。2. Description of the Related Art In the so-called pneumatic caisson method, as shown in FIG. 5, a pressure partition wall (21) is horizontally arranged below a box body (20) having a cylindrical shape, and an airtight excavation work room (22) is provided.
Is formed. By supplying compressed air from an air supply pipe (not shown) to the excavation work room (22), and excavating the ground manually or mechanically while maintaining a high-pressure atmosphere in which the room can withstand groundwater pressure, Pressure caisson (24)
Is sinking under its own weight.
【０００３】このような圧気ケーソン（24）では、水平
に沈下させるために掘削作業室（22）内の地盤を均等に
掘削する必要があるが、実際には、掘削作業室（22）が
広いために均等に掘削するのは容易ではなく、そのため
圧気ケーソン（24）が僅かに傾斜する場合がある。In such a pneumatic caisson (24), it is necessary to evenly excavate the ground in the excavation work room (22) in order to settle it horizontally, but in reality, the excavation work room (22) is large. Due to this, it is not easy to excavate evenly, which may cause the pressure caisson (24) to tilt slightly.
【０００４】しかし、圧気ケーソン（24）が傾くと、掘
削作業室（22）内の高圧空気が函体（20）の刃先（20
ａ）下方を通って函体（20）の外方に噴出し易くなる。
このように高圧空気が噴出すると、函体（20）外方の地
盤が崩壊したり或いは地表面から土砂が吹き上げたりし
て周辺の既設構造物を破壊するおそれがある。また、噴
出した高圧空気が地盤を通る際に未酸化鉱物と化合して
酸欠空気となり、付近のトンネル等の地下構造物に噴出
して酸欠事故を起こすおそれもある。。However, when the pressure caisson (24) is tilted, the high pressure air in the excavation work room (22) causes the cutting edge (20) of the box (20).
a) It is easy to spout to the outside of the box (20) through the lower part.
When high-pressure air is ejected in this way, the ground outside the box (20) may collapse or the earth and sand may blow up from the ground surface, destroying existing structures around it. In addition, the high-pressure air that has ejected may combine with unoxidized minerals to form oxygen-deficient air as it passes through the ground, and may eject into underground structures such as nearby tunnels, causing an oxygen-deficiency accident. .
【０００５】このような不具合を防止するための圧気ケ
ーソンとして、近年、図６に示すような二重壁構造の圧
気ケーソン（25）が開発されている（特開平4−60023号
公報参照）。As a pneumatic caisson for preventing such problems, a pneumatic caisson (25) having a double wall structure as shown in FIG. 6 has been developed in recent years (see Japanese Patent Laid-Open No. 460023).
【０００６】このタイプの圧気ケーソン（25）では、内
側函体（26）及び外側函体（27）（何れも筒状をなす）
が二重に配置されると共に、両函体（26）（27）間の空
間にその全周にわたって圧力隔壁（28）が水平配設され
る。そして、この圧力隔壁（28）の下方空間は、送気管
（図示省略）に連結した高圧の掘削作業室（29）とされ
る。また、内側函体（26）の刃先（26ａ）は、外側函体
（27）の刃先（27ａ）よりも上方に位置するよう高さｈ
だけ切除されている。In this type of pneumatic caisson (25), an inner box (26) and an outer box (27) (both of which are cylindrical)
And the pressure partition walls (28) are horizontally arranged in the space between both boxes (26, 27) over the entire circumference. The space below the pressure partition wall (28) serves as a high-pressure excavation work chamber (29) connected to an air supply pipe (not shown). The height (h) of the cutting edge (26a) of the inner box (26) is higher than that of the cutting edge (27a) of the outer box (27).
Only excised.
【０００７】このような構造の圧気ケーソン（25）であ
れば、両函体（27）間の地盤のみを掘削すればよいの
で、図５に示す圧気ケーソン（24）と比べて掘削面積が
著しく狭くなり、掘削労力を大きく低減させることがで
きる。また、掘削面積が少ないために均等に掘削するこ
とができ、従って、圧気ケーソン（25）を傾斜させるこ
となく確実に水平沈下させることが可能である。万一圧
気ケーソン（25）が傾いても、掘削作業室（29）内の高
圧空気は、矢印Ｐで示すようように、内側函体（26）の
刃先（26ａ）を通って内側函体（26）の内方に噴出し、
外側函体（27）の外方に噴出することはない。従って上
記不具合を回避することが可能となる。With the pneumatic caisson (25) having such a structure, only the ground between the boxes (27) needs to be excavated, so that the excavation area is significantly larger than that of the pneumatic caisson (24) shown in FIG. It becomes narrower and the excavation labor can be greatly reduced. Further, since the excavation area is small, it is possible to excavate uniformly, and therefore, it is possible to surely perform horizontal settlement without tilting the pressure caisson (25). Even if the pressure caisson (25) inclines, the high pressure air in the excavation work chamber (29) passes through the blade edge (26a) of the inner box (26) as shown by an arrow P, and the inner box (26a). 26) Inward,
It does not spout outside the outer box (27). Therefore, it becomes possible to avoid the above-mentioned problem.
【０００８】[0008]
【発明が解決しようとする課題】ところで、二重壁構造
の圧気ケーソン（25）を支持反力の少ない軟質地盤に設
置すると、ケーソンが自然沈下し、図７に示すように、
内側函体（26）及び外側函体（27）の刃先（26ａ）（27
ａ）が両函体（26）（27）間の地盤（30）（以下、内部
地盤と称する）に貫入する場合がある。この場合には内
側函体（26）の刃先（26ａ）周辺が土砂で覆われるた
め、当該刃先（26ａ）周辺の通気性が大きく低下する。By the way, when the pressure caisson (25) having the double wall structure is installed on the soft ground having a small supporting reaction force, the caisson is naturally submerged, and as shown in FIG.
Blade edges (26a) (27) of the inner box (26) and the outer box (27)
There is a case where a) penetrates into the ground (30) (hereinafter, referred to as internal ground) between the boxes (26) and (27). In this case, since the periphery of the cutting edge (26a) of the inner casing (26) is covered with earth and sand, the air permeability around the cutting edge (26a) is greatly reduced.
【０００９】その一方、実際の地盤は、複数種類の地層
が複雑に折り重なって形成されており、掘削作業中に外
側函体（27）の刃先（27ａ）が砂質層等の通気性の高い
層（31）に覆われる場合がある。この場合において、何
らかの理由、例えば掘削作業室（29）内が過剰圧になる
等の理由で高圧空気が室外に逃げようとすると、この高
圧空気はより通気性の高い砂質層（31）を通って外側函
体（27）の外方に噴出し、この結果上述した不具合を引
き起こすようになる。On the other hand, the actual ground is formed by intricately folding a plurality of types of strata, and the cutting edge (27a) of the outer casing (27) is highly breathable such as a sandy layer during excavation work. May be covered by layer (31). In this case, if high-pressure air tries to escape to the outside for some reason, for example, the inside of the excavation work chamber (29) becomes overpressure, this high-pressure air causes the sandy layer (31) having a higher air permeability. It squirts out of the outer case (27) and passes through, resulting in the above-mentioned problems.
【００１０】そこで、本発明は、内側及び外側函体の双
方の刃先が地盤に貫入した場合にも、掘削作業室内の高
圧空気を確実に内側函体の内方に導くことのできる圧気
ケーソンの提供を目的とする。Therefore, the present invention provides a pressure caisson capable of reliably guiding the high-pressure air in the excavation work chamber to the inner side of the inner box even when the cutting edges of both the inner and outer box penetrate the ground. For the purpose of provision.
【００１１】[0011]
【課題を解決するための手段】上記目的の達成のため、
本発明では、筒状の内側函体と、この内側函体の外方に
配した筒状の外側函体とを有し、両函体間の空間に圧力
隔壁を設けて当該空間を上下に気密に区画すると共に、
圧力隔壁の下方に高圧の掘削作業室を形成したものにお
いて、内側函体の下端部に、その外方面に開口する排気
孔をその高さを異ならせて複数設けると共に、各排気孔
を排気路を介して内側函体の内方面に連通させ、且つ、
各排気孔に空気の流通を開放・閉塞する空気流量制御手
段を設けた。[Means for Solving the Problems] To achieve the above object,
In the present invention, it has a tubular inner box and a tubular outer box arranged outside the inner box, and a pressure partition wall is provided in a space between the two boxes to vertically move the space. Airtight partition,
In the case where a high-pressure excavation work chamber is formed below the pressure partition, a plurality of exhaust holes that open to the outer surface of the inner casing are provided at different heights, and each exhaust hole is provided with an exhaust passage. Through the inner side of the inner box, and
Each exhaust hole was provided with air flow rate control means for opening and closing the flow of air.
【００１２】排気路の末端を、掘削作業室よりも上方で
内側函体の内方面に連通させてもよい。The end of the exhaust passage may be communicated with the inner surface of the inner box above the excavation work chamber.
【００１３】また、筒状の函体の下方に圧力隔壁を設け
て当該函体の内方空間を上下に気密に区画し、圧力隔壁
の下方に高圧の掘削作業室を形成したものにおいて、圧
力隔壁の下方に脚壁部を設け、当該脚壁部に、掘削作業
室に高さを異ならせて複数の排気孔を設けると共に、各
排気孔を函体の内方面に連通させ、且つ、各排気孔に空
気の流通を開放・閉塞する空気流量制御手段を設けた。In addition, a pressure partition wall is provided below the cylindrical box to vertically and vertically partition the inner space of the box, and a high pressure excavation work chamber is formed below the pressure partition. A leg wall portion is provided below the partition wall, and the leg wall portion is provided with a plurality of exhaust holes at different heights in the excavation work chamber, and each exhaust hole is communicated with the inner surface of the box, and An air flow rate control means for opening and closing the flow of air is provided in the exhaust hole.
【００１４】[0014]
【作用】予想自然沈下量を考慮してこの範囲内にある空
気量制御手段を開くと共に、残りの空気量制御手段を閉
じ、この状態で圧気ケーソンを軟弱地盤上に設置する。
設置した圧気ケーソンが自然沈下し、外側函体及び内側
函体の刃先が内部地盤中に貫入した後、掘削作業室を高
圧に維持しながら両函体間の地盤を掘削する。掘削作業
室内が過剰圧となると、高圧空気は、外側函体の刃先よ
りも近くに位置する内側函体の排気孔、即ち、内部地盤
に埋没した排気孔のうち最上方の排気孔に流入し、この
後、排気路を介して内側函体の内方に噴出する。なお、
複数の排気孔をその高さを異ならせて設けているので、
土質等の作業条件により圧気ケーソンの自然沈下量が変
化する場合にも容易に対応可能である。In consideration of the expected amount of natural settlement, the air amount control means within this range is opened and the remaining air amount control means is closed, and in this state the pressure caisson is installed on the soft ground.
After the installed pneumatic caisson settles naturally and the cutting edges of the outer and inner boxes penetrate into the inner ground, excavate the ground between the two boxes while maintaining the high pressure in the excavation work room. When the pressure in the excavation work chamber becomes excessive, the high-pressure air flows into the exhaust hole of the inner box located closer to the cutting edge of the outer box, that is, the uppermost exhaust hole buried in the internal ground. After that, it is ejected inward of the inner box through the exhaust passage. In addition,
Since multiple exhaust holes are provided with different heights,
Even if the natural subsidence of the pressure caisson changes depending on the working conditions such as soil quality, it can be easily dealt with.
【００１５】掘削作業室は、地下水圧に対抗し得る程度
の高圧雰囲気下にある。一方、掘削作業室よりも上方に
位置する地盤の水圧は、掘削作業室の内圧に比べて低
い。従って、排気路の末端を、掘削作業室よりも上方で
内側函体の内方面に開口させれば、排気孔に流入した高
圧空気を、圧力差によりスムーズに内側函体の内方に導
くことができる。The excavation work room is under a high pressure atmosphere that can withstand the groundwater pressure. On the other hand, the water pressure of the ground located above the excavation work room is lower than the internal pressure of the excavation work room. Therefore, if the end of the exhaust path is opened above the excavation work chamber to the inner surface of the inner box, the high-pressure air that has flowed into the exhaust hole can be smoothly guided to the inner side of the inner box by the pressure difference. You can
【００１６】単壁構造の圧気ケーソンでは、圧気ケーソ
ンが自然沈下すると、脚壁部の下端部及び函体の刃先が
内部地盤中に貫入する。従って、二重壁構造のケーソン
の場合と同様に、過剰圧となった高圧空気は、内部地盤
に埋没した開放状態の排気孔に流入して函体の内方面に
噴出する。In the single-walled pressure caisson, when the pressure caisson naturally sinks, the lower end of the leg wall and the cutting edge of the box body penetrate into the internal ground. Therefore, as in the case of the double-walled caisson, the overpressured high-pressure air flows into the open exhaust hole buried in the inner ground and is ejected to the inner surface of the box.
【００１７】[0017]
【実施例】以下、本発明の実施例を図１乃至図４に基づ
いて説明する。Embodiments of the present invention will be described below with reference to FIGS.
【００１８】図１（ａ）に示すように、本発明にかかる
圧気ケーソン（１）は、図６に示す圧気ケーソンと同様
の二重壁構造をなすもので、角筒状の内側函体（２）
と、この内側函体（２）の外方に配置された同じく角筒
状をなす外側函体（３）とを具備している。両函体
（２）（３）間の空間の下部には、当該空間を上下に気
密に区画する圧力隔壁（５）が設けられ、この圧力隔壁
（５）の下方に、圧力隔壁（５）、両函体（２）（３）
及び内部地盤（６）とで区画される掘削作業室（７）が
形成されている。掘削作業室（７）には、図示しない送
気管が接続されており、この送気管から供給される高圧
空気によって掘削作業室（７）内が地下水圧に対抗でき
る程度の高圧に維持されている。本発明では、両函体
（２）（３）の刃先（2a）（3a）の位置関係は従来品の
ように限定されるものではない。即ち、何れか一方の刃
先を他方よりも上方に配置してもよく、また、双方を同
一高さに配置してもよい。As shown in FIG. 1 (a), the pneumatic caisson (1) according to the present invention has a double wall structure similar to that of the pneumatic caisson shown in FIG. 2)
And an outer box (3) also in the shape of a rectangular tube arranged outside the inner box (2). In the lower part of the space between the boxes (2) and (3), a pressure partition wall (5) for vertically and vertically partitioning the space is provided, and below the pressure partition wall (5), the pressure partition wall (5) is provided. , Both boxes (2) (3)
An excavation work room (7) is formed that is partitioned by the inner ground (6). An air supply pipe (not shown) is connected to the excavation work room (7), and the high pressure air supplied from the air supply pipe keeps the inside of the excavation work room (7) at a pressure high enough to withstand groundwater pressure. . In the present invention, the positional relationship between the cutting edges (2a) and (3a) of both boxes (2) and (3) is not limited to the conventional one. That is, either one of the cutting edges may be arranged above the other, or both of them may be arranged at the same height.
【００１９】なお、図中の（８）は、掘削した土砂をケ
ーソン（１）外に搬出するためのマテリアルロック及び
作業員の昇降用のマンロックである。Incidentally, (8) in the figure is a material lock for carrying the excavated earth and sand out of the caisson (1) and a man-lock for raising and lowering a worker.
【００２０】図１（ｂ）に示すように、内側函体（２）
下部には、その外方面（外側函体（３）と対向する面）
に開口する排気孔（10ａ）〜（10ｆ）が高さを異ならせ
て複数形成されている。また、内側函体（２）の下部に
は、各排気孔（10ａ）〜（10ｆ）と連通する排気路（1
1）が設けられており、この排気路（11）の末端は斜め
上方に延びて内側函体（２）の内方面（12）に開口して
いる。排気路（11）の末端は、空気の排出をスムーズに
行なうべく掘削作業室（７）の内圧よりも低い水圧を有
する部分、即ち掘削作業室（７）よりも上方に開口部
（11ａ）を備えている。この排気孔（10ａ）〜（10ｆ）
及び排気路（11）は、これらを一組として内側函体
（２）の全周にわたって複数組設けられている。As shown in FIG. 1 (b), the inner box (2)
At the bottom, its outer surface (surface facing the outer box (3))
A plurality of exhaust holes (10a) to (10f) are formed at different heights. In addition, an exhaust path (1) communicating with the exhaust holes (10a) to (10f) is provided in the lower part of the inner casing (2).
1) is provided, and the end of the exhaust passage (11) extends obliquely upward and opens to the inner surface (12) of the inner box (2). The end of the exhaust passage (11) has a portion having a water pressure lower than the internal pressure of the excavation work chamber (7), that is, an opening (11a) above the excavation work chamber (7) in order to smoothly discharge air. I have it. These exhaust holes (10a) to (10f)
A plurality of exhaust paths (11) are provided as a set over the entire circumference of the inner box (2).
【００２１】各排気孔（10ａ）〜（10ｆ）には、空気の
流通を開放・閉塞する空気流量制御手段、例えばバルブ
（図示省略）が設けられる。このバルブは、掘削作業室
（７）内の作業員（13）に直接操作させる他、自動掘削
に対応可能となるよう遠隔操作可能に構成してもよい。Each of the exhaust holes (10a) to (10f) is provided with an air flow rate control means such as a valve (not shown) for opening and closing the flow of air. This valve may be directly operated by a worker (13) in the excavation work room (7) or may be remotely operable so as to be compatible with automatic excavation.
【００２２】なお、一つの排気路（11）に設ける排気孔
の数は任意である。また、上述のように排気路（11）を
各排気孔（10ａ）〜（10ｆ）で共用するほか、図２に示
すように、各排気孔（10）にそれぞれ独立して排気路
（11）を接続し、各排気路（11）の末端をそれぞれ内側
函体（２）の内方面（12）に開口させてもよい。即ち、
各排気孔（10ａ）〜（10ｆ）が内側函体（２）の内方面
（12）と連通するのであれば、排気路（11）の形状、本
数等は特に問わない。また、図３に示すように、排気路
（11）を複数の横管（11ａ）と、各横管（11ａ）と連結
した縦管（11ｂ）とで構成し、各横管（11ａ）に複数の
開口穴を設けてこの開口穴を排気孔（10）に連通させて
もよい。この構造であれば、排気路（11）として用いら
れる管材の使用量を削減することが可能となる。The number of exhaust holes provided in one exhaust passage (11) is arbitrary. In addition, the exhaust passage (11) is shared by the exhaust holes (10a) to (10f) as described above, and as shown in FIG. 2, the exhaust passage (11) is independently provided to each exhaust hole (10). May be connected, and the ends of the exhaust passages (11) may be opened to the inner surface (12) of the inner box (2). That is,
The shape and number of the exhaust passages (11) are not particularly limited as long as the exhaust holes (10a) to (10f) communicate with the inner surface (12) of the inner box (2). Further, as shown in FIG. 3, the exhaust passage (11) is composed of a plurality of horizontal pipes (11a) and a vertical pipe (11b) connected to each horizontal pipe (11a). A plurality of opening holes may be provided and the opening holes may be communicated with the exhaust hole (10). With this structure, it is possible to reduce the amount of pipe material used as the exhaust passage (11).
【００２３】以下、図１に示す圧気ケーソン（１）を軟
弱地盤に沈設する際の作業手順を説明する。The work procedure for submerging the pneumatic caisson (1) shown in FIG. 1 on soft ground will be described below.
【００２４】まず、各排気孔（10ａ）〜（10ｆ）のう
ち、予想される自然沈下量（ｔ）の範囲内にある排気孔
（10ａ）〜（10ｄ）のバルブを開き、その他のバルブを
閉じて圧気ケーソン（１）を地盤上に設置する。これに
より、圧気ケーソン（１）が自然沈下し、両函体（２）
（３）の刃先（2a）（3a）が内部地盤（６）に所定量
（ｔ）だけ貫入する。圧気ケーソン（１）の静止後、実
際の沈下量が予想沈下量（ｔ）よりも少なく、そのため
内部地盤（６）の表面が、開放状態の排気孔（10ａ）〜
（10ｄ）のうち最上方に位置する排気孔（10ｄ）よりも
下方に位置するのであれば、当該排気孔（10ｄ）のバル
ブを閉じて高圧空気の漏出を防止する。その反対に、実
際の沈下量が予想沈下量（ｔ）よりも大きく、そのため
内部地盤（６）の表面が、閉塞状態の排気孔（10ｅ）
（10ｆ）のうち最下方の排気孔（10ｅ）よりも上方に位
置するのであれば、当該排気孔（10ｅ）のバルブを開
く。First, among the exhaust holes (10a) to (10f), open the valves of the exhaust holes (10a) to (10d) within the range of the expected natural settlement amount (t) and open the other valves. Close and place the pneumatic caisson (1) on the ground. This caused the pneumatic caisson (1) to subside naturally, and both boxes (2)
The blade edges (2a) and (3a) of (3) penetrate the internal ground (6) by a predetermined amount (t). After the pressure caisson (1) is at rest, the actual subsidence amount is less than the expected subsidence amount (t), so that the surface of the internal ground (6) has an open exhaust hole (10a)-
If it is located below the uppermost exhaust hole (10d) of (10d), the valve of the exhaust hole (10d) is closed to prevent leakage of high-pressure air. On the contrary, the actual subsidence amount is larger than the expected subsidence amount (t), so that the surface of the internal ground (6) has a closed exhaust hole (10e).
If it is located above the lowermost exhaust hole (10e) of (10f), the valve of the exhaust hole (10e) is opened.
【００２５】次いで送気管から圧縮空気を供給し、掘削
作業室（７）内を地下水圧に対抗できる程度の高圧雰囲
気にする。この状態で掘削作業室（７）内の作業者（1
3）若しくは自動掘削機が内部地盤（６）を掘削する
と、圧気ケーソン（１）が徐々に沈下する。掘削に伴っ
て土質が変化し、そのため自然沈下量（ｔ）が変動した
場合は、内部地盤（６）中の排気孔が開放状態になり、
その他の排気孔が閉塞状態となるよう作業者が各排気孔
（10ａ）〜（10ｆ）のバルブを適宜操作する。Next, compressed air is supplied from the air supply pipe to create a high pressure atmosphere in the excavation work room (7) that can withstand the groundwater pressure. In this state, the worker (1
3) Or when an automatic excavator excavates the internal ground (6), the pneumatic caisson (1) gradually sinks. When the soil quality changes due to excavation, and therefore the natural settlement (t) changes, the exhaust holes in the internal ground (6) become open,
An operator appropriately operates the valves of the exhaust holes (10a) to (10f) so that the other exhaust holes are closed.
【００２６】図示の状態で、何らかの理由、例えば掘削
作業室（７）が過剰圧になる等の理由で高圧空気が室外
に逃げようとすると、この高圧空気は、内部地盤（６）
の表層部を通気して内部地盤（６）の表面直下に位置す
る排気孔（10ｄ）に流入し、排気路（11）を通って内側
函体（２）の内方面（12）に噴出する。この時、外側函
体（３）の刃先（3a）近傍に通気性のよい砂質層があっ
ても、当該刃先（3a）は排気孔（10ｄ）に比べて内部地
盤（６）の表面から遠く離れているため、高圧空気は砂
質層を通気せずに排気孔（10ｄ）に流入する。従って、
地質条件とは無関係に、常時高圧空気を内側函体（２）
の内方に導くことが可能となる。また、本発明では、排
気路（11）の末端を掘削作業室（７）の上方に開口させ
ているので、圧力差により、高圧空気は逆流することな
くスムーズに内側函体（２）の内方に排出される。In the illustrated state, if high pressure air tries to escape to the outside for some reason, for example, the excavation work chamber (7) becomes overpressure, this high pressure air will be discharged into the internal ground (6).
Ventilates the surface layer of the inner ground (6), flows into the exhaust hole (10d) located directly below the surface of the inner ground (6), and passes through the exhaust passage (11) and is ejected to the inner surface (12) of the inner box (2). . At this time, even if there is a sandy layer with good air permeability near the blade edge (3a) of the outer casing (3), the blade edge (3a) is closer to the surface of the internal ground (6) than the exhaust hole (10d). Since it is far away, the high pressure air does not pass through the sandy layer and flows into the exhaust hole (10d). Therefore,
Irrespective of the geological conditions, high-pressure air is constantly supplied inside the box (2)
It becomes possible to lead inward. Further, in the present invention, since the end of the exhaust passage (11) is opened above the excavation work chamber (7), the high pressure air does not flow backward due to the pressure difference, and the inside of the inner box (2) smoothly flows. Is discharged to the person.
【００２７】なお、空気流量制御手段としては、バルブ
の他、空気の流通を開放・閉塞し得る他のあらゆる手段
が使用可能である。例えば、排気孔（10ａ）〜（10ｆ）
の内径面と密着する形状の棒状体を排気孔（10ａ）〜
（10ｆ）に抜き差したり、あるいは、排気孔（10ａ）〜
（10ｆ）を閉塞し得る蓋状体を脱着することにより、排
気孔（10ａ）〜（10ｆ）を開放・閉塞してもよい。棒状
体や蓋状体は、バルブに比べてコスト的に安価であるの
で排気孔（10ａ）〜（10ｆ）が多数設けられている場合
に好適であるが、密閉性等の動作の確実性の点で劣るの
でこれが要求される場合はバルブを用いるのが望まし
い。As the air flow control means, other than the valve, any other means capable of opening / closing the flow of air can be used. For example, exhaust holes (10a) to (10f)
Exhaust hole (10a)-
(10f) and pull out, or exhaust hole (10a) ~
The exhaust holes (10a) to (10f) may be opened / closed by detaching the lid-like body capable of closing the (10f). Since the rod-shaped body and the lid-shaped body are less expensive than the valve in terms of cost, they are suitable when a large number of exhaust holes (10a) to (10f) are provided, but the operation reliability such as hermeticity is ensured. Since this is inferior in point, it is preferable to use a valve when this is required.
【００２８】図４は、本発明を図５に示す単壁構造の圧
気ケーソンに適用した場合の実施例である。このタイプ
の圧気ケーソン（1'）は、特にケーソンが小型であり、
二重壁構造としてもほとんど掘削量を低減させることが
できず、却ってコスト高となる場合に有用である。FIG. 4 shows an embodiment in which the present invention is applied to the pressure caisson having a single wall structure shown in FIG. This type of pneumatic caisson (1 ') has a particularly small caisson,
Even if the double wall structure is used, the amount of excavation can hardly be reduced, which is useful when the cost is rather high.
【００２９】圧力隔壁（5'）の下面には、筒状をなす函
体（15）の対向二壁間を横断して脚壁部（16）が形成さ
れる。脚壁部（16）の下部は、下方に向けて幅狭となる
断面三角形型に形成されており、その内部には、函体
（15）の内方面（12）、即ち圧力隔壁（5'）の上面に両
端部を開口させたＶ字型の排気路（11）が脚壁部（16）
の延設方向に沿って等間隔に複数設けられている。この
脚壁部（16）、圧力隔壁（5'）、函体（15）及び内部地
盤（６）で区切られた空間は掘削作業室（７）となる。
各排気路（11）には、複数の排気孔（10）が縦並びに設
けられており、さらに各排気孔（10）には、バルブ等の
空気流量制御手段（図示省略）が設けられている。A leg wall portion (16) is formed on the lower surface of the pressure partition wall (5 ') so as to traverse between the two opposing walls of the tubular box body (15). The lower portion of the leg wall portion (16) is formed in a triangular shape in cross section that narrows downward, and inside thereof, the inner surface (12) of the box (15), that is, the pressure partition wall (5 '). ) The leg wall (16) has a V-shaped exhaust passage (11) with both ends open on the upper surface of
Are provided at equal intervals along the extending direction of. The space defined by the leg wall portion (16), the pressure partition wall (5 '), the box body (15) and the internal ground (6) becomes an excavation work room (7).
Each exhaust passage (11) is provided with a plurality of exhaust holes (10) vertically, and each exhaust hole (10) is provided with an air flow rate control means (not shown) such as a valve. .
【００３０】この構成によっても、図１に示すものと同
様に、掘削作業室（７）内から漏れた高圧空気を、排気
孔（10）及び排気路（11）を介して函体（15）の内方に
導くことができ、従って、当該高圧空気が函体（15）の
外側に噴出するのを防止することが可能となる。With this structure as well, similar to that shown in FIG. 1, the high pressure air leaking from the excavation work chamber (7) is passed through the exhaust hole (10) and the exhaust passage (11) to the box (15). It is possible to guide the high pressure air to the outside of the box (15).
【００３１】[0031]
【発明の効果】このように、本発明によれば、内側及び
外側函体の双方の刃先が内部地盤に貫入した場合にも、
掘削作業室内の高圧空気を、内部地盤中に埋没した開放
状態の排気孔を介して確実に内側函体の内方に排出する
ことができる。従って、外側函体の刃先の周辺の土質と
は無関係に、高圧空気の外側函体外方への噴出を防止す
ることができ、この噴出空気による周辺構造物の破壊や
酸欠事故の発生等を回避することが可能となる。また、
圧力隔壁の下方に脚壁部を設け、当該脚壁部に、高さを
異ならせて複数の排気孔を設けると共に、各排気孔を函
体の内方面に連通させ、且つ、各排気孔に空気の流通を
開放・閉塞する空気流量制御手段を設けても、同様の効
果を得ることができる。As described above, according to the present invention, even when the cutting edges of both the inner and outer boxes penetrate into the inner ground,
The high-pressure air in the excavation work chamber can be reliably discharged to the inner side of the inner box through the open exhaust hole buried in the inner ground. Therefore, regardless of the soil quality around the cutting edge of the outer casing, it is possible to prevent high-pressure air from spouting to the outside of the outer casing. It is possible to avoid it. Also,
A leg wall is provided below the pressure partition wall, and a plurality of exhaust holes are formed in the leg wall at different heights, and each exhaust hole is communicated with the inner surface of the box, and each exhaust hole is connected to each exhaust hole. The same effect can be obtained by providing an air flow rate control means for opening / closing the air flow.
【００３２】排気路の末端を掘削作業室よりも上方で内
側函体の内方面に開口させれば、高圧空気の排出をスム
ーズに行なうことができる。High-pressure air can be discharged smoothly by opening the end of the exhaust passage to the inner surface of the inner casing above the excavation work chamber.
【図１】本発明を二重壁構造の圧気ケーソンに適用した
場合の一実施例を示す断面図（ａ）、及び、（ａ）図中
のＡ部分の拡大図である。FIG. 1 is a cross-sectional view (a) showing an embodiment in which the present invention is applied to a double-walled pressure air caisson, and an enlarged view of a portion A in the drawing.
【図２】本発明の他の実施例を示す拡大断面図である。FIG. 2 is an enlarged cross-sectional view showing another embodiment of the present invention.
【図３】本発明の他の実施例を示す図であり、掘削作業
室からみた内側函体下部の正面図である。FIG. 3 is a view showing another embodiment of the present invention and is a front view of the lower portion of the inner box as seen from the excavation work chamber.
【図４】本発明を単壁構造の圧気ケーソンに適用した場
合の実施例を示す断面図（ａ）、及び、（ａ）図中のB
−B線での断面図（ｂ）である。FIG. 4 is a sectional view (a) showing an embodiment in which the present invention is applied to a single-walled pressure air caisson, and B in the drawing (a).
It is sectional drawing (b) by the -B line.
【図５】従来の単壁構造のケーソンの断面図である。FIG. 5 is a cross-sectional view of a conventional single-wall structure caisson.
【図６】従来の二重壁構造のケーソンの断面図である。FIG. 6 is a cross-sectional view of a conventional double-walled caisson.
【図７】内側及び外側函体の双方の刃先が内部地盤に貫
入した場合を示す拡大断面図である。FIG. 7 is an enlarged cross-sectional view showing a case where the blade edges of both the inner and outer boxes penetrate into the inner ground.
１ 圧気ケーソン ２ 内側ケーソン ３ 外側ケーソン ５ 圧力隔壁 ６ 内部地盤 ７ 掘削作業室 10 排気孔 11 排気路 12 内方面 16 脚壁部 1 Pneumatic caisson 2 Inner caisson 3 Outer caisson 5 Pressure bulkhead 6 Inner ground 7 Excavation chamber 10 Exhaust hole 11 Exhaust passage 12 Inner surface 16 Leg wall
Claims (3)
に配した筒状の外側函体とを有し、両函体間の空間に圧
力隔壁を設けて当該空間を上下に気密に区画すると共
に、圧力隔壁の下方に高圧の掘削作業室を形成したもの
において、 前記内側函体の下端部に、その外方面に開口する排気孔
を高さを異ならせて複数設けると共に、各排気孔を排気
路を介して内側函体の内方に連通させ、且つ、各排気孔
に空気の流通を開放・閉塞する空気流量制御手段を設け
たことを特徴とする圧気ケーソン。1. A cylindrical inner box, and a cylindrical outer box arranged outside the inner box, and a pressure partition wall is provided in the space between the two boxes to raise and lower the space. In the one in which a high-pressure excavation work chamber is formed below the pressure partition wall in the airtight manner, a plurality of exhaust holes opening to the outer surface of the inner box are provided at different heights, and A pneumatic caisson characterized in that each exhaust hole is communicated with the inside of the inner casing via an exhaust passage, and each exhaust hole is provided with an air flow rate control means for opening and closing the flow of air.
上方で内側函体の内方面に開口させたことを特徴とする
請求項１記載の圧気ケーソン。2. The pneumatic caisson according to claim 1, wherein the end of the exhaust passage is opened to the inner surface of the inner box above the excavation work chamber.
該函体の内方空間を上下に気密に区画し、圧力隔壁の下
方に高圧の掘削作業室を形成したものにおいて、 前記圧力隔壁の下方に脚壁部を設け、当該脚壁部に、高
さを異ならせて複数の排気孔を設けると共に、各排気孔
を函体の内方面に連通させ、且つ、各排気孔に空気の流
通を開放・閉塞する空気流量制御手段を設けたことを特
徴とする圧気ケーソン。3. A structure in which a pressure partition wall is provided below a cylindrical box body to vertically and vertically partition an inner space of the box body, and a high pressure excavation work chamber is formed below the pressure partition wall. A leg wall is provided below the pressure partition wall, and a plurality of exhaust holes are formed in the leg wall at different heights, and each exhaust hole is communicated with the inner surface of the box, and each exhaust hole is connected to each exhaust hole. A pneumatic caisson characterized by being provided with air flow rate control means for opening and closing the flow of air.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6013299A JP2521032B2 (en) | 1994-02-07 | 1994-02-07 | Tense causson |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6013299A JP2521032B2 (en) | 1994-02-07 | 1994-02-07 | Tense causson |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07216904A true JPH07216904A (en) | 1995-08-15 |
| JP2521032B2 JP2521032B2 (en) | 1996-07-31 |
Family
ID=11829314
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6013299A Expired - Lifetime JP2521032B2 (en) | 1994-02-07 | 1994-02-07 | Tense causson |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2521032B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106545026A (en) * | 2016-10-27 | 2017-03-29 | 中交第二航务工程局有限公司 | Open caisson subregion based on remaining core soil in advance excavates method for sinking |
| CN112627215A (en) * | 2020-12-18 | 2021-04-09 | 中铁大桥局集团第四工程有限公司 | Construction method for correcting torsion of large-scale water open caisson |
-
1994
- 1994-02-07 JP JP6013299A patent/JP2521032B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106545026A (en) * | 2016-10-27 | 2017-03-29 | 中交第二航务工程局有限公司 | Open caisson subregion based on remaining core soil in advance excavates method for sinking |
| CN112627215A (en) * | 2020-12-18 | 2021-04-09 | 中铁大桥局集团第四工程有限公司 | Construction method for correcting torsion of large-scale water open caisson |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2521032B2 (en) | 1996-07-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3965687A (en) | Apparatus for anchoring a structure to the floor of a body of water | |
| CN112377139A (en) | Suction anchor wellhead device and installation method thereof | |
| JPH04231511A (en) | Composite structure constructible in subsoil water area under garbage pit in multistage reinforcing method for protecting garbage pit, and constructing method therefor | |
| CN114606964B (en) | Foundation pit dewatering method used under complex geological conditions | |
| JP2625073B2 (en) | Equipment buried underwater | |
| JP2521032B2 (en) | Tense causson | |
| JP2003261930A (en) | Consolidation improvement method for water bottom soft ground | |
| JPS61169512A (en) | Air-expansion type flexible rising and falling film dam | |
| US20230332369A1 (en) | Suction anchor or well support foundation for use in permeable water bottom formations | |
| JP3008323B2 (en) | Multi-aquifer stratified pumping system | |
| JP3967473B2 (en) | Construction method of underground structure | |
| US2587835A (en) | Method and means for underwater constructions | |
| US2580017A (en) | Caisson | |
| JPS58222290A (en) | Drilling of tunnel under water bottom | |
| JP3650861B2 (en) | Method for improving pressure-bearing ground directly under existing structure and water stop device used for the method | |
| CN114233383A (en) | Construction method of water storage system of opencast coal mine | |
| JP2718241B2 (en) | Foundation construction method on soft submarine ground | |
| JP3877816B2 (en) | Pneumatic caisson settlement method | |
| CA1039521A (en) | Method and apparatus for supporting a drilling platform on the ocean floor | |
| WO2002063106A1 (en) | A method for installing submerged oil and gas wells, and apparatus for the same | |
| JP2004003229A (en) | Method for constructing vertical shaft | |
| JP3877817B2 (en) | Excavation sediment transport method in pneumatic caisson | |
| JP2779679B2 (en) | Construction method of underwater tunnel and underwater excavator | |
| JP2010024684A (en) | Air leakage prevention equipment for caisson construction method | |
| JP4679597B2 (en) | Leakage prevention device in submersible construction method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 19960312 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090517 Year of fee payment: 13 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090517 Year of fee payment: 13 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100517 Year of fee payment: 14 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110517 Year of fee payment: 15 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110517 Year of fee payment: 15 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120517 Year of fee payment: 16 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130517 Year of fee payment: 17 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140517 Year of fee payment: 18 |
|
| EXPY | Cancellation because of completion of term |