JPS626011A - Scouring prevention work for caisson foundation - Google Patents
Scouring prevention work for caisson foundationInfo
- Publication number
- JPS626011A JPS626011A JP14058285A JP14058285A JPS626011A JP S626011 A JPS626011 A JP S626011A JP 14058285 A JP14058285 A JP 14058285A JP 14058285 A JP14058285 A JP 14058285A JP S626011 A JPS626011 A JP S626011A
- Authority
- JP
- Japan
- Prior art keywords
- caisson
- sheet
- scouring
- cutting edge
- sheet material
- 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.)
- Pending
Links
Landscapes
- Revetment (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は下端面に刃口を有するケーソンを水底に沈設す
る際の水底の基礎の洗掘を防止するためのケーソン基礎
の洗掘防止工法に関するものである。[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for preventing scouring of a caisson foundation to prevent scouring of the foundation at the bottom of the water when a caisson having a cutting edge on the lower end surface is sunk to the bottom of the water. It is related to.
従来、ケーソン式防波堤等を水底に沈設する際には、先
ず、洗掘防止のためのマットやシートを敷設し、その上
に捨石によりマウンドを作り、その表面を均らした後、
陸上で予め製造したコンクリート製等のケーソンを曳航
し、前記マウンド上に設置し、ケーソン内に中詰砂等の
充填作業を行ない、次に、波により洗掘を受ける側のマ
ウンドの表面を潜水夫等の作業によって根固めブロック
で覆うことにより根固めを行って洗掘を防止している。Conventionally, when sinking a caisson-type breakwater to the bottom of the water, a mat or sheet was first laid to prevent scouring, a mound was created with rubble on top of it, and the surface was leveled.
A concrete caisson made in advance on land is towed, placed on the mound, and the caisson is filled with sand, etc., and then the surface of the mound on the side that will be scoured by waves is submerged. The husband and others work to prevent scouring by covering the ground with foot protection blocks.
しかしながら、このような洗掘防止用の根固め工法では
、洗掘防止用マットやシート等の敷設工事、マウンド面
の均らし工事、根固めブロックの陸上での製作、根固め
ブロックの海上運搬、根固めブロックのクレーン船等に
よる据付は工事等の多くの工程の作業が必要であった。However, this method of foot protection to prevent scour requires installation of anti-scouring mats, sheets, etc., leveling of the mound surface, production of foot protection blocks on land, transportation of foot protection blocks by sea, Installation of foot protection blocks using a crane ship, etc. required many steps such as construction work.
従って、工期が長くなると共に、気象、海象条件の影響
を受け、経済性にも問題があった。Therefore, not only did the construction period become long, but it was also affected by weather and sea conditions, and there were also problems in terms of economic efficiency.
そこで、前記従来の技術の対策として、通水性の布等の
材料からなる根固め袋を巻き、その端部をケーソンの底
縁部に固定した状態でケーソンを沈設し、その根固め袋
内にモルタルを充填して水底上に広開して洗掘を防止す
る方法が特開昭５８−９１２２４号公報によって提案さ
れている。Therefore, as a countermeasure to the above-mentioned conventional technology, a caisson is submerged with a foot protection bag made of water-permeable cloth or other material wrapped around it and its ends fixed to the bottom edge of the caisson, and the caisson is placed inside the foot protection bag. Japanese Patent Laid-Open No. 58-91224 proposes a method of filling mortar and spreading it widely on the water bottom to prevent scour.
しかし、前記工法においては、ケーソンを沈設すると同
時にケーソンの周囲の洗掘が始まるが、ケーソンを沈設
してその内部に中詰砂を充填した後、根固め袋内にモル
タルを注入して洗掘防止作業が完了するまでに時間がか
かるために、その間に洗掘が進行するという問題がある
と共に、ケーソンを沈設した後で洗掘防止施工を行うの
で、工期が長くなるという欠点がある。However, in the above construction method, scouring around the caisson starts at the same time as the caisson is sunk, but after the caisson is sunk and the inside is filled with sand, mortar is injected into the foot protection bag and the scouring begins. Since it takes time to complete the prevention work, there is a problem that scouring progresses during that time, and since the scouring prevention work is carried out after the caissons are sunk, there is a disadvantage that the construction period becomes longer.
更に、別の工法として、不織布マットに網を被せ、その
両端に錘りを設けたものを水底に敷設し、その上に基礎
を構築する方法があるが、この工法においてはケーソン
内部のマットは不要であると共に、コンクリート打設の
障害となる上に不経済でもある。Another construction method is to cover a non-woven mat with a net and attach weights to both ends, and then lay it on the bottom of the water and build a foundation on top of it. In this construction method, the mat inside the caisson is Not only is this unnecessary, but it also obstructs concrete pouring and is uneconomical.
本発明は、従来のケーソンの洗掘防止工法の問題点を解
消するために得られたものであり、予め洗掘防止策がな
された状態でケーソンの沈設が可能で、ケーソン沈設中
における洗掘を完全に防止でき、しかもその洗掘防止の
ための工期が短く、経済的なケーソン基礎の洗掘防止工
法を提供することを目的とするものである。The present invention was obtained in order to solve the problems of the conventional caisson scour prevention method, and it is possible to sink the caisson with measures taken to prevent scour in advance, and prevents scour during the caisson sinking. The purpose of the present invention is to provide an economical method for preventing caisson foundations from scouring, which can completely prevent scouring, and has a short construction period.
前記目的を達成するための本発明は、下端面の外周面よ
り、切断されたシート状物の端部を支持可能な長さだけ
内方に位置させて刃口を突出したケーソンを、水底に敷
設した洗掘防止用シート状物上に沈設して前記刃口に沿
って前記洗掘防止用シート状物を切断し、工事の進行に
応じて前記ケーソンの下端面で支持された洗掘防止用シ
ート状物を除去することを特徴とするケーソン基礎の洗
掘防止工法である。To achieve the above object, the present invention has a caisson with a cutting edge protruding from the outer circumferential surface of the lower end surface by a length sufficient to support the cut sheet-like material at the bottom of the water. The scouring prevention sheet is placed on top of the laid scouring prevention sheet material, and the scouring prevention sheet material is cut along the cutting edge, and as the construction progresses, the scouring prevention sheet material is supported by the lower end surface of the caisson. This is a method for preventing scouring of caisson foundations, which is characterized by the removal of sheet-like materials.
以下図面を参照して本発明の詳細な説明する。なお、本
実施例においては鋼製ケーソンを使用した場合について
説明する。The present invention will be described in detail below with reference to the drawings. In this example, a case where a steel caisson is used will be described.
第１図は本発明を実施するためのケーソンの下部の一例
を示すものであって、ケーソン５の下端面５ｂには刃口
６が溶接６ａ等の手段によって固定されている。この刃
口６は高さがｒｈＪであって、その先端部に片刃６ｂが
形成され、ケーソン５の外周面５ａより距離ｒａＪだけ
内側に位置させて固定されている。FIG. 1 shows an example of a lower part of a caisson for carrying out the present invention, and a cutting edge 6 is fixed to the lower end surface 5b of the caisson 5 by means such as welding 6a. The blade mouth 6 has a height rhJ, has a single blade 6b formed at its tip, and is fixed so as to be located inside the outer peripheral surface 5a of the caisson 5 by a distance raJ.
この距離ａは、刃口６によってケーソン５の内部と外部
に分離された洗掘防止用シート状物を押さえ込む部分で
あって、洗掘防止用シート状物が十分その効果を発揮す
ることができる程度の長さが必要である。This distance a is the part that holds down the scour prevention sheet material separated into the inside and outside of the caisson 5 by the cutting edge 6, and allows the scour prevention sheet material to fully exert its effect. A certain length is required.
また、ケーソン５の内周面５ｂは傾斜面に形成され、そ
の内周面と刃口６との間に距離ｒｂＪが形成されている
。この距離すは、切断された洗掘防止用シート状物の内
、ケーソン５の内部に位置するものの端部を押さえ込む
ためのものである。Further, the inner circumferential surface 5b of the caisson 5 is formed as an inclined surface, and a distance rbJ is formed between the inner circumferential surface and the cutting edge 6. This spacing is for holding down the end portion of the cut scour prevention sheet material located inside the caisson 5.
刃口６の高さｒｈＪは、ケーソン５を水底４に沈設させ
た際に、この刃口６によって洗掘防止用シート状物を自
動的に切断するのに十分な長さとする。The height rhJ of the cutting edge 6 is made long enough to automatically cut the scouring prevention sheet material by the cutting edge 6 when the caisson 5 is sunk in the water bottom 4.
第２図は別の形式の刃口６を設けたケーソン５を示すも
のであって、この刃口６には両刃６ｃが形成されている
。この刃口６の位置と寸法とは前記第１図のケーソンの
場合と同様である。FIG. 2 shows a caisson 5 provided with another type of cutting edge 6, in which a double edge 6c is formed. The position and dimensions of this cutting edge 6 are the same as in the case of the caisson shown in FIG. 1 above.
次に、本発明に係るケーソン基礎の洗掘防止工法につい
て説明する。Next, a method for preventing scouring of a caisson foundation according to the present invention will be explained.
まず、第３図に示すような洗掘防止用シート状物８を準
備する。この洗掘防止用シート状物８は、ナイロン、ポ
リエステル等の耐蝕性で強度のある繊維を使用したシー
ト状物、または、このシート状物よりも耐摩性に優れた
ゴム引き布からなるシート状物１を使用し、このシート
状物１の両端部に袋２を形成し、この袋２の内部に錘り
３を挿入したものである。この錘り３としては、コンク
リート、土砂、砕石等、袋２内に充填が容易で安価な材
料が使用される。First, a scour-preventing sheet material 8 as shown in FIG. 3 is prepared. This anti-scouring sheet material 8 is a sheet material made of corrosion-resistant and strong fibers such as nylon or polyester, or a sheet material made of rubberized cloth that has better abrasion resistance than this sheet material. A bag 2 is formed at both ends of the sheet-like material 1, and a weight 3 is inserted into the bag 2. As the weight 3, an inexpensive material that can be easily filled into the bag 2, such as concrete, earth and sand, or crushed stone, is used.
そして、第４図に示すように、ケーソン５を沈設する位
置の水底４に、前記洗掘防止用シート状物８の複数枚が
互いに隣接し、かつ各シート状物８の縁部が重なるよう
に敷設する。As shown in FIG. 4, a plurality of scour-preventing sheet materials 8 are placed adjacent to each other on the water bottom 4 at the position where the caisson 5 is to be sunk, and the edges of each sheet material 8 overlap. to be laid down.
なお、この洗掘防止用シート状物８を敷設する範囲は、
ケーソン５の底縁部を覆う範囲で充分である。In addition, the area where this scour prevention sheet-like material 8 is laid is:
It is sufficient to cover the bottom edge of the caisson 5.
この工程においては、錘り３を予め陸上で袋２内に設け
た洗掘防止用シート状物８を使用するか、あるいは一端
の錘り３を予め陸上で施工し、他端の錘り３を水底に敷
設後に施工しても良いが、流れに対する施工性の面から
後者の方が優れている。In this process, the weight 3 is installed in advance on land inside the bag 2 using a scouring prevention sheet-like material 8, or the weight 3 at one end is installed in advance on land and the weight 3 at the other end is installed. It is also possible to construct the pipe after laying it on the bottom of the water, but the latter method is better in terms of workability against the flow.
前記のように、洗掘防止用シート状物８を水底４の所定
の位置に敷設したならば、第５図に示すようにこの洗掘
防止用シート状物８上にケーソン５をフローチングクレ
ーン等を利用して沈設する。この際、前記ケーソン５の
下端面５ｂに設けられた刃口６で洗掘防止用シート状物
８のシート状物１をケーソン５の下端面５ｂに沿って切
断する。As described above, once the scour prevention sheet material 8 is laid at a predetermined position on the water bottom 4, the caisson 5 is placed on the scour prevention sheet material 8 by a floating crane as shown in FIG. etc. to sink it. At this time, the sheet-like material 1 of the scour-preventing sheet-like material 8 is cut along the lower end surface 5b of the caisson 5 using the cutting edge 6 provided on the lower end surface 5b of the caisson 5.
ケーソン５の下端面５ｂはシート状物１の切断された端
部を押さえ込むものであって、シート状物１の端部１ａ
は比較的強く押さえ込まれ、他方の端部１ｂは前記端部
１ａより比較的弱く押さえ込まれている。The lower end surface 5b of the caisson 5 is for holding down the cut end of the sheet-like material 1, and the end surface 5b of the sheet-like material 1 is
is pressed relatively strongly, and the other end 1b is pressed relatively weakly than the end 1a.
前記のように実施された結果、ケーソン５の洗掘防止を
必要とする範囲はシート状物１で被覆防護され、ケーソ
ン５の下端面５ｂよりはみ出している水底４上のシート
状物１は錘り２と下端面５ｂとによって押さえ込まれ、
位置決めされている。As a result of the implementation as described above, the area of the caisson 5 that requires protection from scouring is covered and protected with the sheet-like material 1, and the sheet-like material 1 on the water bottom 4 protruding from the lower end surface 5b of the caisson 5 is covered with a weight. is pressed down by the lever 2 and the lower end surface 5b,
Positioned.
次に、刃口６より内側のシート状物１を錘り３と共に取
り除くことにより、ケーソン５の底部７には水底４が露
出されるので、その部分の掘削、基礎コンクリート打設
等の作業を直ちに実施できる。なお、ケーソン５の下端
面５ｂに設けた刃口６は、ケーソン５の内側に偏って設
けられているために刃口６で切断された外側のシート状
物１の端部は比較的強く押さえられ、内側のシート状物
１は軽（押さえられているので、内側のシート状物１は
簡単に除去することができる。Next, by removing the sheet-like material 1 inside the cutting edge 6 along with the weight 3, the water bottom 4 is exposed at the bottom 7 of the caisson 5, so that work such as excavation and foundation concrete pouring in that area is carried out. Can be implemented immediately. Note that the cutting edge 6 provided on the lower end surface 5b of the caisson 5 is biased toward the inside of the caisson 5, so that the edge of the outer sheet-like material 1 cut by the cutting edge 6 is pressed relatively firmly. Since the inner sheet-like material 1 is lightly pressed, the inner sheet-like material 1 can be easily removed.
前記、実施例においては鋼製ケーソン５の沈設について
説明したが、下端面に刃口６を設けたものならば、コン
クリート製ケーソンの場合でも本発明を適用することは
可能である。In the above-described embodiments, the steel caisson 5 is sunken, but the present invention can also be applied to a concrete caisson as long as the cutting edge 6 is provided on the lower end surface.
本発明は、下端面５ｂに刃口６を設けたケーソン５を使
用し、水底４に敷設した洗掘防止用シート状物８上にケ
ーソン５を沈設し、前記ケーソン５の下端面５ｂに設け
られた刃口６によって前記洗掘防止用シート状物８をケ
ーソン５の下端面５ｂに沿って切断し、工事の進行に応
じて前記洗掘防止用シート状物８を除去するので、次の
効果を奏することができる。The present invention uses a caisson 5 with a cutting edge 6 provided on the lower end surface 5b, the caisson 5 is sunk on a scour prevention sheet material 8 laid on the water bottom 4, and the caisson 5 is installed on the lower end surface 5b of the caisson 5. The scouring prevention sheet material 8 is cut along the lower end surface 5b of the caisson 5 using the cutter 6, and the scouring prevention sheet material 8 is removed as the construction progresses. It can be effective.
ケーソンの沈設に先立って、洗掘防止用シート状物によ
って水底を保護した状態でケーソンを沈設するので、ケ
ーソンの沈設作業中の洗掘を防止できる。Prior to sinking the caisson, the caisson is sunk with the bottom of the water protected by a scour-preventing sheet material, so scour can be prevented during the caisson sinking operation.
また、洗掘防止用シート状物８はケーソン５の下端面５
ｂに設けた刃口６によってケーソンの内部と外部で分離
できるように切断されているので、ケーソン５の内部の
洗掘防止用シート状物を除去して水底面を露出させ、直
ちに地盤を掘削し、基礎コンクリートを打設することが
できる。Further, the scour prevention sheet material 8 is attached to the lower end surface 5 of the caisson 5.
Since the caisson is cut by the cutting edge 6 provided in b so that the inside and outside of the caisson can be separated, the scour prevention sheet material inside the caisson 5 is removed to expose the bottom surface of the water, and the ground is excavated immediately. Then, foundation concrete can be poured.
洗掘防止用シート状物の敷設はケーソンの沈設に先立っ
て行うので、全体の工期には影響しない。Since the sheet material to prevent scour will be laid before the caisson is laid, it will not affect the overall construction period.
なお、前記実施例において詳述した構造を有する洗掘防
止用シート状物を使用することによってケーソンの下端
部が位置する限定された水底部分を保護することができ
るので、このシート状物の敷設面積が小さく、このシー
ト状物の敷設、除去、掘削等の各種の作業を効率的、経
済的に行うことができる。It should be noted that by using the scour prevention sheet material having the structure detailed in the above embodiment, it is possible to protect the limited water bottom area where the lower end of the caisson is located, so the use of this sheet material The area is small, and various operations such as laying, removing, and excavating the sheet-like material can be performed efficiently and economically.
第１図及び第２図は刃口を有するケーソンの要部を示す
断面図、第３図は本発明の洗掘防止工法に使用する洗掘
防止用シート状物の一実施例を示す斜視図、第４図はケ
ーソンの沈設作業状態を示す要部説明図、第５図は第４
図のＸ−Ｘ矢視断面図である。
１・・・シート状物、２・・・袋、３・・・錘り、４・
・・水底、５・・・鋼製ケーソン、６・・・刃口、８・
・・洗掘防止用シート状物。FIGS. 1 and 2 are cross-sectional views showing the main parts of a caisson having a cutting edge, and FIG. 3 is a perspective view showing an example of a scour prevention sheet material used in the scour prevention method of the present invention. , Figure 4 is an explanatory diagram of the main parts showing the state of the caisson sinking work, and Figure 5 is an explanatory diagram of the main parts of the caisson.
It is a sectional view taken along the line XX in the figure. 1... Sheet-like material, 2... Bag, 3... Weight, 4...
...bottom, 5.steel caisson, 6.blade mouth, 8.
・Sheet-like material for preventing scouring.
Claims (1)
持可能な長さだけ内方に位置させて刃口を突出したケー
ソンを、水底に敷設した洗掘防止用シート状物上に沈設
して前記刃口に沿って前記洗掘防止用シート状物を切断
し、工事の進行に応じて前記ケーソンの下端面で支持さ
れた洗掘防止用シート状物を除去することを特徴とする
ケーソン基礎の洗掘防止工法。A caisson with a cutting edge protruding from the outer peripheral surface of the lower end by a length sufficient to support the cut sheet end is placed on top of a scouring prevention sheet placed on the bottom of the water. The sheet material for preventing scour is cut by sinking the material along the cutting edge, and the sheet material for preventing scour supported by the lower end surface of the caisson is removed as construction progresses. A method to prevent scouring of caisson foundations.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14058285A JPS626011A (en) | 1985-06-28 | 1985-06-28 | Scouring prevention work for caisson foundation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14058285A JPS626011A (en) | 1985-06-28 | 1985-06-28 | Scouring prevention work for caisson foundation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS626011A true JPS626011A (en) | 1987-01-13 |
Family
ID=15272039
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14058285A Pending JPS626011A (en) | 1985-06-28 | 1985-06-28 | Scouring prevention work for caisson foundation |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS626011A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0528453U (en) * | 1991-05-09 | 1993-04-16 | 三郎 宮崎 | Discharge device |
| JPH10219654A (en) * | 1997-01-31 | 1998-08-18 | Tokyu Constr Co Ltd | Mat-like bulkhead or bulkhead bed structure |
| JP2000212929A (en) * | 1999-01-27 | 2000-08-02 | Ohmoto Gumi Co Ltd | Method of containing sludge |
-
1985
- 1985-06-28 JP JP14058285A patent/JPS626011A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0528453U (en) * | 1991-05-09 | 1993-04-16 | 三郎 宮崎 | Discharge device |
| JPH10219654A (en) * | 1997-01-31 | 1998-08-18 | Tokyu Constr Co Ltd | Mat-like bulkhead or bulkhead bed structure |
| JP2000212929A (en) * | 1999-01-27 | 2000-08-02 | Ohmoto Gumi Co Ltd | Method of containing sludge |
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