JPS6041271B2 - Undersea water supply device - Google Patents

Description

【発明の詳細な説明】 この発明は、海水よりもわずかに比重が軽くなるように
作られた大口径の海中送水管を用いて、海底にその一端
を固定したロープで海面下一定の深度となる海中に、浮
力と係留力との均合によって支えられて伸びる海中の淡
水送水装置に関するものであって、本発明を実施すると
、海によって隔てられた水の需要地域と供給地域とを海
水を支持体として容易にかつ安価に送水管で結んで淡水
を送ることができるので、用水問題を一気に解決し得る
ものである。[Detailed Description of the Invention] This invention uses a large-diameter underwater water pipe made to have a specific gravity slightly lower than seawater, and uses a rope with one end fixed to the seabed to reach a certain depth below the sea surface. The present invention relates to an underwater freshwater water conveying system that extends into the sea supported by the balance of buoyancy and mooring force.When the present invention is implemented, seawater can be used to connect water demand areas and water supply areas separated by the sea. Since it can be used as a support and can be easily and inexpensively connected with a water pipe to transport fresh water, the problem of water use can be solved at once.

現在まで実施されている淡水送水パイプラインは、通常
は陸上を経由して鉄管やコンクリート管等によって設け
られるが、陸上では道路や建造物や河川等の関係から、
地上のあらゆる事物とは立体交差となるように敷設せら
れ、地上構築物がある場合はもっぱら地下を、河川や谷
等の凹形地形による場合にはもっぱら水道橋等を架して
敷かれていた。Freshwater water pipelines that have been implemented to date are usually constructed using iron pipes, concrete pipes, etc. via land, but on land, due to roads, buildings, rivers, etc.
It was laid so that it was a grade-separated intersection with all things above ground, and when there were above-ground structures, it was built mostly underground, and when it was built on concave terrain such as rivers and valleys, it was built mostly over aqueducts.

特に管が地下埋設される場合には、地圧や内部水圧に十
分に耐えるためと、地震や地層変動をも考慮して相当な
肉厚管を使う必要があり、その上埋設工事には多額の費
用を要するもので、大幹線のパイプラインのように大口
隆替の敷設となると、地形の悪い所ではその工事費は膨
大なものとなるもので、山脈や高地等を越えて水を引く
場合には導水トンネルの工事が必要となる。また一方、
海によって隔てられた水の需要地と供給水源地との関係
の場合は現在まで未だほとんど手がつけられていない。
ただ液体を海上輸送する方法として、士砂と水を同時に
吸上げて輸送するポンプ式の７変蝶船の吐出管や、タン
カーから陸上の貯油施設に重油等を送る油送管等はよく
研究せられ実施もされているが、これらは通常は可鏡性
のあるホース状の管を自己浮遊又はフロート付き浮遊等
によって水面上に浮かせて使用するものである。また止
むを得ず油送管を海底に敷設する場合には、通常硬質管
を、時には可操性の耐圧ホース状管を海底に沈めた状態
で使用され、船舶の往釆の激しい場所等では必要に応じ
て更に堀削し海底土中に管を埋め込む方法も採用されて
いる。しかしこれら俊蝶や油送による場合にはいずれも
管の口径はそれほど大きいものではなく、通常その口径
は０．３ｈからｌｍ位のもので、水道用本管に用いられ
るものよりはるかに細いものである。しかし通常「水需
要量は巨大でり、石油輸送管よりはるかに大きな超大口
蓬管を必要とする。そのため先述のように導水ラインを
陸上に敷設する場合は技術的経済的困難性がつきまとう
。また、超大口径管を海底に敷設するに当っては海低ケ
ーブル敷設船のような専用船を用うるとしても、曲げる
ことのできない大きな重量管を垂れ下げながら連続して
接続しながら敷設し船を少しづつ前進させてゆく方法は
困難をともない、また仮りにうまく接続敷設されたとし
ても、深い海底に敷設されると、潜水夫や作業船を使っ
ての維持管理や修理にも困難がともない、ヘドロの集積
した海底では管の確認もむつかしくなる。In particular, when pipes are buried underground, it is necessary to use fairly thick pipes to withstand ground pressure and internal water pressure, and to take into consideration earthquakes and strata changes, and the burial work requires a large amount of money. When constructing large-scale pipelines such as large trunk pipelines, the construction costs would be enormous in areas with poor terrain, and water would have to be drawn across mountains, highlands, etc. In some cases, construction of a water conveyance tunnel will be required. On the other hand,
Until now, little work has been done on the relationship between water demand areas and water supply areas that are separated by the ocean.
However, as methods for transporting liquids by sea, there has been much research into methods such as the discharge pipes of pump-type seven-change ships that simultaneously suck up and transport sand and water, and the oil pipes that transport heavy oil, etc. from tankers to onshore oil storage facilities. However, these methods usually use a hose-like tube with a reflective surface that floats on the water surface by self-floating or floating with a float. In addition, when it is unavoidable to lay an oil transmission pipe on the seabed, a hard pipe is usually used, and sometimes a flexible pressure-resistant hose-like pipe is submerged on the seabed. If necessary, a method of digging further and burying the pipe in the seabed soil is also adopted. However, in the case of these pipes and oil pipes, the diameter of the pipe is not so large, and the diameter is usually between 0.3h and 1m, which is much smaller than that used for water mains. It is. However, ``the demand for water is usually huge, requiring ultra-large-mouth pipes that are much larger than oil transport pipes.As a result, as mentioned earlier, laying water conveyance lines on land is fraught with technical and economic difficulties. In addition, even if a special ship such as a low-sea cable-laying ship can be used to lay ultra-large diameter pipes on the seabed, it is difficult to lay large heavy pipes that cannot be bent and connect them continuously. It is difficult to move forward little by little, and even if the connections are successfully laid, if they are laid deep under the sea, maintenance and repair using divers and work boats will be difficult. It becomes difficult to identify the pipes on the ocean floor where sludge has accumulated.

そこでここに本発明として、海水よりわずかに比重が軽
くなるような構造を持った肉薄の超大口蚤管を利用し、
該管を先ず海面に浮かべながら全長にわたって接合し、
このようにして成る長いパイプラインを管に無理な力が
かかって破損しないように同時に均等に海中へ沈めるた
めの工法により、管全長を海面下のある一定の深さの位
置に止つた状態に固定することによって、大水量を送る
最大な送水ラインを容易かつ安価に施工することができ
るもので、その保守管理に必要な潜水夫や作業船を十分
に活用できるような都合のよい深さに安定した状態で設
置することのできる新しい淡水の海中送水施設を提供す
るものである。Therefore, as part of the present invention, we utilize a thin, ultra-large-mouthed tube with a structure that makes the specific gravity slightly lighter than seawater.
First, the pipes are joined along their entire length while floating on the sea surface,
This construction method allows the long pipeline to be submerged evenly into the sea at the same time to prevent damage due to excessive force being applied to the pipe, so that the entire length of the pipe remains at a certain depth below the sea surface. By fixing the line, it is possible to easily and inexpensively construct the largest water supply line that can carry a large amount of water, and at a convenient depth to fully utilize the divers and work boats needed for its maintenance. The purpose is to provide a new freshwater underwater water transmission facility that can be installed in a stable state.

以下、本発明について、図面によりその構成および施工
法について詳しく述べる。Hereinafter, the structure and construction method of the present invention will be described in detail with reference to the drawings.

本願発明装置に使用される海中送水管１は、内面および
外面をモルタルやプラスチック等によってラィニングさ
れた肉薄鋼管２や肉薄ステンレス管２等を用いて、その
外面全周を独立気泡を有する硬質プラスチックの発泡体
３等で包被し、さらにその外面を軟かし、発泡体３を保
護するための薄板による保護外被４をかぶせた構造のも
ので、金属管１の重量に応じて発泡体３の厚さを調節し
て、第１図に例示するように、海水中に入れた場合に管
１がわずかに海水面５上に現われる程度の比重となるよ
うに製作されたものを使用する。The underwater water pipe 1 used in the device of the present invention uses a thin-walled steel pipe 2 or a thin-walled stainless steel pipe 2 whose inner and outer surfaces are lined with mortar, plastic, etc., and the entire outer surface is lined with hard plastic having closed cells. It has a structure in which the metal tube 1 is covered with a foam 3, etc., and then covered with a protective jacket 4 made of a thin plate to soften the outer surface and protect the foam 3. The thickness of the tube is adjusted so that the specific gravity of the tube 1 is such that when immersed in seawater, the tube 1 slightly appears above the seawater surface 5, as shown in FIG. 1.

先ず最初にこのような海中送水管１を多数海面に浮かべ
、熔接やメカニカル後手等によって連結して海面上に長
大なパイプラインを作りあげる。次いで管１に浮箱６を
取付けた吊上ロープ７を適当な間隔を置いて多数取付け
、また同じ場所に重り８を取りつけた係留ロープ９をも
多数取付けて海上に放つ。その場合浮箱６は第６図に示
すようにそれの内部の下方に硬質発泡体等の軽量材料で
作られた浮体１０が浮箱６内を上方ヘビストンのように
滑動できるように装着され、この浮体１０上方の浮箱６
内は大きい空気室１１になっていて、浮体１０の体積い
っぱいに大きな浮力を与えているため、海へ放たれた管
１はこれに取りつけられた沈降用重り８に対して管１自
体の浮力に浮箱６の浮力が加つて、沈降しようとする力
に浮力がわずかに打ち勝って沈まず、浮箱６内を貫通し
た藤１２の下端の止め論１３に掛けられた吊上ロープ７
に吊上げられた状態で、管１は第２図に示すように海面
近くの海中に浮かぶ。工事は波の静かな季節を選んで実
施するが、このように接合した長い管１を海面近くに浮
かべてから、各浮箱６の上方にねじ込んである火薬１４
を装填した爆発栓１５に対して、外部から電気導線１６
を介して沢山の爆発栓１５をいっせいに通電発火させて
爆発させる。この爆発によって爆発栓１５の上部の蓋が
吹き飛ばされると空気室１１内の空気は外部へ通じるこ
ととなるので、重り８の重さによって海底へ引き降ろさ
れようとする力が浮体１０に働いてこれを下方から浮箱
６の上方へ押し上げ、そのため空気室１１の空気は排除
せられる。その結果、排除された空気量に相当する分の
浮力を失うことになるので、海中送水管１はゆっくりと
沈降して第３図のように海底１７に近ずく。しかし浮箱
６の構成材料の大部分を占める発泡体の中には相当の空
気が保存されていてかなりの浮力がまだ残っているため
、海中送水管１は自体の浮力と併せて海底１７に重り８
が到達した状態で管１はあらかじめ一定の長さに調節し
たロープ９を介して海底１７より立上つた姿で海中に係
留される。この場合、係留ロープ９の長さをああらかじ
め測量した海底１７の地形に合わせて調整しておくこと
によって、変化の多い海底１７の地形に影響されること
なく海中の一定の深さをどこまでも真直ぐに配管するこ
とができるので、曲げることのほとんどできない超大口
蓬管の敷設には極めて有利である。次いで海中作業船を
用いたりして海底１７に鉄筋コンクリート製の直杭を打
込んだり、コンクリート製の螺旋杭１８をねじ込んだり
し、あるいは本格的な重りとして恒久的な係留用コンク
リートブロック等を投下して、これ等に係留ロープ９を
つけ替えて、第４図および第５図に示すように海中送水
装置の工事を完了する。First, a large number of such underwater water pipes 1 are floated on the sea surface and connected by welding, mechanical backing, etc. to create a long pipeline on the sea surface. Next, a large number of lifting ropes 7 to which floating boxes 6 are attached are attached to the pipe 1 at appropriate intervals, and a large number of mooring ropes 9 to which weights 8 are attached to the same locations are also attached and released into the sea. In this case, as shown in FIG. 6, the floating body 10 made of a lightweight material such as hard foam is attached to the lower part of the inside of the floating box 6 so as to be able to slide upward within the floating box 6 like a heavistone. Floating box 6 above this floating body 10
There is a large air chamber 11 inside, which gives a large buoyant force to the entire volume of the floating body 10, so that when the tube 1 is released into the sea, the buoyancy of the tube 1 itself is greater than the sinking weight 8 attached to it. The buoyant force of the floating box 6 is added to the floating box 6, and the buoyant force slightly overcomes the force of the floating box 6, and the lifting rope 7, which is hung on the stop 13 at the lower end of the rattan 12 that has penetrated the inside of the floating box 6, does not sink.
In the suspended state, the tube 1 floats in the sea near the sea surface, as shown in FIG. The construction work will be carried out by selecting a season when the waves are calm, and after floating the long pipes 1 connected in this way near the sea surface, the gunpowder 14 screwed into the top of each floating box 6 will be installed.
An electric conductor 16 is connected from the outside to the explosive plug 15 loaded with
A large number of explosive plugs 15 are energized and ignited at the same time to cause an explosion. When the upper lid of the explosion plug 15 is blown off by this explosion, the air inside the air chamber 11 will be communicated to the outside, and the weight of the weight 8 will exert a force on the floating body 10 to pull it down to the seabed. This is pushed up from below to above the floating box 6, so that the air in the air chamber 11 is removed. As a result, the buoyancy corresponding to the amount of air removed is lost, so the underwater water pipe 1 slowly sinks and approaches the seabed 17 as shown in FIG. 3. However, since a considerable amount of air is stored in the foam that makes up the majority of the constituent material of the floating box 6, and a considerable amount of buoyancy remains, the underwater water pipe 1, along with its own buoyancy, is suspended on the seabed 17. weight 8
When the pipe 1 reaches the position, the pipe 1 is moored in the sea in a manner that it rises above the seabed 17 via a rope 9 that has been adjusted to a certain length in advance. In this case, by adjusting the length of the mooring rope 9 in accordance with the topography of the seabed 17 that has been surveyed in advance, the length of the mooring rope 9 can be adjusted to suit the topography of the seabed 17 that has been surveyed in advance. This is extremely advantageous for installing ultra-large-mouthed pipes that can hardly be bent. Next, using an underwater work vessel, a straight reinforced concrete pile is driven into the seabed 17, a concrete spiral pile 18 is screwed in, or a permanent mooring concrete block or the like is dropped as a full-scale weight. Then, mooring ropes 9 are attached to these and the construction of the underwater water conveyance system is completed as shown in FIGS. 4 and 5.

この場合管１の沈降と仮係留に用いられる沈降用の重り
８は大形バケットに砂機等を入れて用い、使用ずみの後
は砂磯だけを海底１７に捨えるようにする。そして技後
にはこの送水管１，１・・・・・・の一方より淡水を送
り込んで、最初から入っていた海水を他方の口より押し
出して置換し、以後継続して淡水を送水する。このよう
にして構築された海中送水管のラインは、管１自体が有
する浮力と、わずかではあるが海水に対する淡水の比重
の軽さ等によって巨大な肉薄大口蚤管１が無理な力が加
えられることなく海水によって支えられることになるの
で、浮箱６の浮力と併せて海底１７の２つの固定部を介
して張られたそれぞれの係留ロープ９を緊張させて管１
を一定の深度に保ちながら動揺するのを防ぐことができ
るとともに、管１は肉薄ではあるが非可榛性の硬質管で
あるので、係留ロープ９の間隔を十分にあげることがで
きるから係留点は最少限の数でよいこととなって工費を
極めて節減し得る。In this case, the settling weight 8 used for settling and temporarily mooring the pipe 1 is used by placing a sand machine or the like in a large bucket, and after use, only the sandy rock is disposed of on the seabed 17. After the procedure, fresh water is sent from one of the water pipes 1, 1, . . . , and the seawater that was originally in the water pipes is pushed out from the other port to replace it, and fresh water is continued to be fed from then on. In the underwater water pipe line constructed in this way, the huge thin large-mouthed pipe 1 is subjected to excessive force due to the buoyancy of the pipe 1 itself and the light specific gravity of freshwater relative to seawater, although it is slight. Since the pipe 1 is supported by the seawater without any movement, the mooring ropes 9 stretched through the two fixed parts of the seabed 17 are tensioned together with the buoyancy of the floating box 6.
In addition, since the tube 1 is a thin but non-flexible hard tube, the distance between the mooring ropes 9 can be increased sufficiently, so that the mooring point can be kept at a constant depth. Since only a minimum number is required, construction costs can be significantly reduced.

また従来一般に実施されている陸上の固定配管や埋設管
はもちろん海底土中に埋設された送水管等が、地震や地
殻変動に対して極めて弱いことを考えると、本発明のよ
うな一定深度における海水の中層に作られる配管は極め
て安全であり、また水面下のある程度の深さに配置され
ることによって台風等によってもたらされる波浪による
被害も全く心配がなく、また同時に船舶の航行にも支障
をもたらすことがない。さらに別の見地から海中送水装
置の管は、深度が深くなって内部の水圧が高まっても同
時に外部の海水の水圧も高まって、全長にわたって内外
の水圧差は海水と淡水の比重差だけを考えたわずかな内
部水圧の上昇でよいからどこも均等にしかもほとんど零
に保つことができるので、内部の水圧を特別に高くしな
い限り管肇は極めて薄くすることができ、このことに関
しても費用を著しく少くすることができる。In addition, considering that not only fixed piping and buried pipes on land, but also water transmission pipes buried in seabed soil, which have been commonly implemented in the past, are extremely vulnerable to earthquakes and crustal movements, Piping built in the middle layer of seawater is extremely safe, and since it is placed at a certain depth below the water surface, there is no fear of damage from waves caused by typhoons, etc., and at the same time it does not interfere with ship navigation. nothing to bring about. From another perspective, even though the depth of the pipes in the underwater water supply system increases and the internal water pressure increases, the external seawater pressure also increases at the same time. Since only a small increase in internal water pressure is required, it can be maintained uniformly and almost at zero everywhere, so unless the internal water pressure is particularly high, the tube sleeve can be made extremely thin, and this also significantly reduces costs. can do.

すなわち、大口蓬管として大量の水を低速低圧で送る方
法をとれば、コストの安い肉薄管として陸上ではとうて
い利用できないような超大口隆替を用いることが可能で
あるから、管内流速が遅いと言うことを十分に償って余
りがあり、大量の淡水を送ることができる。この点につ
いては地形の影響を受ける陸上での配管では施工技術上
や経済上から管径に制限を受けるから、いきおい少水量
に高速高圧送水法をとらざるを得ない。そうなると強度
の大きい肉厚管を使用し、特別な水蜜接合を要するもの
であって、たとえ少しの水もれを生じても附近に多大の
障害を与えるものである。しかるに本発明の場合は低速
低圧の送水であるため極めて簡易な接合方法や管全長の
熔接接合も可能となり、仮りに極所的に少々の水もれが
生じても海水中であるために他への損害を与えることも
なく、また送水するため極〈わずかに管内の水圧を高め
るから海水が管内へ逆流して淡水中へ混入するおそれも
ない。このような本発明による送水装置は、ここで今ま
で述べた実施例の外に、湖水等の淡水中を特に浄化した
上質の淡水を輸送する場合にも陸上を送水するよりもは
るかに安価にして容易に目的を達し、あるいはまた汚染
海域の海水中を外洋のきれいな海水を導入するために輸
送することができるもので、これによって例えば工業地
帯や大都会を沿岸に有する内海の養殖漁業や海水浴場の
発展などにも貢献することができよう。In other words, if we use a method to send a large amount of water at low speed and low pressure using a large-mouth pipe, it is possible to use a super-large-mouth pipe, which is a cheap thin-walled pipe that cannot be used on land. It is more than enough to compensate for what it says, and can deliver large amounts of fresh water. Regarding this point, in land piping, which is affected by the topography, there are restrictions on pipe diameter due to construction technology and economical reasons, so high-speed, high-pressure water delivery methods have no choice but to handle small amounts of water. This would require the use of strong, thick-walled pipes and special water joints, and even a small leak would cause a great deal of damage to the surrounding area. However, in the case of the present invention, since the water is conveyed at low speed and low pressure, it is possible to use an extremely simple joining method and to weld the entire length of the pipe, and even if a small amount of water leaks in a localized area, it can be used in other places because it is in seawater. Also, since the water pressure inside the pipe is increased slightly to convey water, there is no risk of seawater flowing back into the pipe and mixing with fresh water. In addition to the embodiments described so far, the water conveying device according to the present invention can also be used to transport high-quality fresh water that has been particularly purified from freshwater such as lake water at a much lower cost than conveying water over land. This can be easily achieved by transporting seawater from polluted areas to introduce clean seawater from the open ocean, which can be used, for example, for aquaculture and seawater production in inland seas with industrial areas and large cities on their shores. It could also contribute to the development of bathhouses.

【図面の簡単な説明】[Brief explanation of drawings]

第１図はこの発明の実施に使用する海中送水管を単独で
海水面に浮かべた状態を示す横断面図、第２図はこの発
明装置を構築施工するために先ず第１図の状態の管に重
りと浮箱を取りつけて海面近くの海中に浮かべた状態を
示す横断面図、第３図は第２図に続いて浮箱の浮力を減
じて管を海底近くまで沈降させた状態を示す横断面図、
第４図は第３図の状態となった管列に添って係留用の螺
旋杭を海底にねじ込んだ状態を示す横断面図、第５図は
重りを取除いて管を係留するロープを螺旋杭につけ替え
た本発明の工程における最終状態を示す横断面図、第６
図は第２図じ汎蜂の図に示す浮箱部の拡大詳細断面図、
第７図は第６図に示す浮箱の一部に取付けられた爆発栓
の部分を示す拡大断面図、第８図は本発明を海中に構築
した実施例の姿を示す見取図である。 第１図 第２図 第３図 第４図 第５図 第７図 第６図 第８図Fig. 1 is a cross-sectional view showing the underwater water pipe used to carry out this invention floating alone on the sea surface, and Fig. 2 shows the pipe in the state shown in Fig. 1 in order to construct and work the device of this invention. A cross-sectional view showing the tube floating near the sea surface with weights and a floating box attached to it. Figure 3, following on from Figure 2, shows the tube sinking close to the seabed by reducing the buoyancy of the floating box. cross section,
Figure 4 is a cross-sectional view showing the condition in which the spiral piles for mooring are screwed into the seabed along the row of pipes as shown in Figure 3. Figure 5 is a cross-sectional view showing the state in which the helical piles for mooring are screwed into the seabed along the row of pipes as shown in Figure 3. 6th cross-sectional view showing the final state in the process of the present invention after replacing the pile with
The figure is an enlarged detailed cross-sectional view of the floating box shown in Figure 2.
FIG. 7 is an enlarged sectional view showing a portion of the explosion plug attached to a part of the floating box shown in FIG. 6, and FIG. 8 is a sketch showing an embodiment of the present invention constructed underwater. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 Figure 6 Figure 8

Claims (1)

【特許請求の範囲】 １ 海水等よりもわずかに比重が軽くなるように鉄管等
の外面を独立気泡性の発泡体等で包被した海中送水管を
用いて、該管自体とこれに取付けた浮箱の合成浮力によ
つて、海底にその一端を固定しかつ他端を該管に取りつ
けた係留ロープを緊張させた状態で海面より一定の深度
となる海中に長く連結固定されることを特徴とする海中
送水装置。 ２ 海水等よりもわずかに比重が軽くなるように鉄管等
の外面を独立気泡性の発泡体等で包被した海中送水管を
、海面より一定の深度となる海中に係留ロープ介して長
く連結した状態で海中送水装置として係留固定させるた
めに、最初海面に多数浮かべて接続した海中送水管に先
ず未だ空気室を有しかつそれ自体も若干の浮力を有する
沢山の浮箱を取りつけると同時に、別に沢山の沈降用重
りをも取付けてわずかに沈降力に打勝つて海面近くの海
中に浮かんだ状態に保たせ、次いで各浮箱にある爆発栓
を電気発火によつていつせいに爆発させて空気室の上部
を開栓して水圧によつて浮箱内下方の浮体を押上げて排
気して空気室を消滅させ、管全長にわたつて浮力を同時
に減少させながら管を全長にわたつていつせいに海面下
一定の設定予定深度および位置まで沈降させて係留固定
することを特徴とする海中送水装置を構築する工法。[Scope of Claims] 1. Using an underwater water pipe whose outer surface is covered with a closed-cell foam or the like so that the specific gravity is slightly lower than that of seawater, etc., the pipe itself and the water pipe attached to it are used. Due to the synthetic buoyancy of the floating box, one end of the floating box is fixed to the seabed and the other end is attached to the tube, and the mooring rope is kept under tension, allowing the floating box to be connected and fixed for a long time in the sea at a certain depth from the sea surface. Undersea water conveyance system. 2 Undersea water pipes whose outer surfaces are covered with closed-cell foam, etc. so that the specific gravity is slightly lighter than seawater, etc. are connected for a long time in the sea at a certain depth below the sea surface via mooring ropes. In order to be moored and fixed as an underwater water conveyance system, we first attached many floating boxes that still had air chambers and had some buoyancy to the underwater water pipes that were first floated on the sea surface and connected. A large number of sinking weights were also attached to slightly overcome the sinking force and keep it floating near the sea surface, and then the explosion plugs in each floating box were detonated at any time by electric ignition. The upper part of the air chamber is opened and the water pressure pushes up the floating body in the lower part of the floating box and exhausts the air, eliminating the air chamber. A construction method for constructing an underwater water conveyance system that is characterized by being lowered to a predetermined predetermined depth and position below the sea surface and then moored and fixed.