JP3655883B2

JP3655883B2 - Groundwater pumping method

Info

Publication number: JP3655883B2
Application number: JP2002067559A
Authority: JP
Inventors: 茂吉高橋; 修一松村
Original assignee: Asahi Techno Corp
Current assignee: Asahi Techno Corp
Priority date: 2002-03-12
Filing date: 2002-03-12
Publication date: 2005-06-02
Anticipated expiration: 2022-03-12
Also published as: JP2003268759A

Description

【０００１】
【発明の属する技術分野】
本発明は、地下工事のために地盤を掘削したり、あるいは地盤改良などを行う際に地下水位を低下させるために地下水を揚水するための技術に関するものである。
【０００２】
【従来の技術】
従来から地下工事のために地盤を掘削したり、あるいは地盤改良などを行う際に地下水位を低下させるために地下水を揚水することが行われている。このように地下水を揚水して地下水位を低下させることで目的とする地盤の土砂の含水率が低下して、掘削工事や掘削した土砂の処理が容易に行えるものである。
【０００３】
地下水を揚水するに当たっては、地盤に埋設したケーシング管の下端部に設けた通水部から地下水を流入させて流入した地下水を揚水手段により揚水することで行うものであり、揚水方法としては例えば、自然水位と井戸内水位との水頭差を利用して排水するディープウエル法や、ディープウエル装置に減圧手段を設けて井戸内を減圧することで、地下水位の更なる低下を図るようにしたバキュームディープウエル法が知られている。また、他の従来例としては、特開平２０００−２７１７０が知られている。この特開平２０００−２７１７０は、ケーシング管の下端部にストレーナ装置を設け、水頭差及び減圧手段でケーシング管内を減圧することによるバキューム力により地下水をストレーナ装置を介してケーシング管内に集水し、このようにしてストレーナ装置を介してケーシング管内に集水した地下水を揚水ポンプにより汲み上げるようにしている。
【０００４】
しかしながら、上記いずれの従来例においても、単に地盤にケーシング管を埋設して、上記したそれぞれの方法により地下水の揚水を行っているのであるが、地盤にケーシング管を埋設した場合、ケーシング管の下端部に設けた通水部が必ずしも地盤中における水の存在する部分に一致するとは限らず、むしろ、ケーシング管の下端部の通水部と地盤中における水の存在する部分とが一致しない場合が多く、また、ケーシング管の通水部の周囲の地質が通水し難い地質の場合がある。このため、上記のような各方法により（水頭差、あるいは水頭差とバキューム力により）ケーシング管の下端部の通水部からケーシング管内に地下水を集水するに当たって、地下水がケーシング管の下部の周囲の地盤を通水してスムーズに通水部側に流れにくく、集水効果が悪いという問題があった。
【０００５】
【発明が解決しようとする課題】
本発明は上記の点に鑑みてなされたものであり、地盤に埋設したケーシング管に集水した地下水を揚水するに先だって、予めケーシング管の周囲の地盤を通水部側に向けてスムーズに地下水が流れやすくなるように改質して効果的に集水、揚水ができる地下水揚水方法を提供することを課題とするものである。
【０００６】
【課題を解決するための手段】
上記課題を解決するために本発明に係る地下水揚水方法は、ケーシング管３の下端部の下部筒部３ａに通水部２を設けると共に該下部筒部３ａの外周に隙間２０を介して下部筒部３ａを囲む上下方向に長い多数の水通過部２３を有するストレーナ部２１を設け、上記ケーシング管３を地盤１に埋設して該ケーシング管３の下端部に設けたストレーナ部２１の多数の水通過部２３、下部筒部３ａとストレーナ部２１との間の隙間２０を介して通水部２から地下水を流入させて流入した地下水を揚水手段４により揚水するに先立って、ケーシング管３の下端部に設けた上記通水部２から加圧水を上記下部筒部３ａとストレーナ部２１との間の隙間２０、ストレーナ部２１の多数の水通過部２３を介して地盤１中に圧送してケーシング管３下部の周囲の地盤１を加圧水により割裂して割裂通水路を形成するように周囲の地盤１を改質する地盤改質工程を実施し、この地盤改質工程を実施した後で、揚水手段４により周辺の地盤１に形成した割裂通水路を介して地下水をストレーナ部２１の多数の水通過部２３、下部筒部３ａとストレーナ部２１との間の隙間２０を経て通水部２からケーシング管３内に流入させて揚水する本揚水工程を実施する方法であって、上記のようにケーシング管３下部の周囲の地盤１を加圧水により割裂して割裂通水路を形成するように周囲の地盤１を改質するに当たって、加圧水の地盤１への圧送と、加圧水の地盤１への圧送により飽和状態となった地盤１の地下水を真空で吸引すると共に揚水手段４により揚水することを交互に繰り返して地盤１を改質することを特徴とするものである。このような方法を採用することにより、本揚水を実行する前に、あらかじめケーシング管３の下部の周囲の地盤１に割裂通水路を形成するように周囲の地盤１を改質し、このようにケーシング管３の下部の周囲の地盤１を改質した後に揚水手段４によりケーシング管３内に集水した地下水を揚水する本揚水を実行することで、ケーシング管３内に効果的に地下水を集水して効率的に揚水することができるものである。特に、ケーシング管３の下部の下部筒部３ａに設けた通水部２、隙間２０、ストレーナ部２１の多数の水通過部２３を介して加圧水を地盤１中に圧送して割裂通水路を形成し、地下水を上記ストレーナ部２１の多数の水通過部２３、隙間２０、通水部２を介して流入させて揚水するので、地盤改質工程とこれに続く本揚水工程とを同一の地下揚水装置により行うことができるものであり、また、ケーシング管３下部の周囲の地盤１を加圧水により割裂して割裂通水路を形成するように周囲の地盤１を改質するに当たって、加圧水の地盤１への圧送と、加圧水の地盤１への圧送により飽和状態となった地盤１の地下水を真空で吸引すると共に揚水手段４により揚水することを交互に繰り返して地盤１を改質するから、本揚水を実行する前に、あらかじめケーシング管３の下部の周囲の地盤１に割裂通水路を形成するように周囲の地盤１を改質するに当たって、加圧水を連続してケーシング管３下部の周囲の地盤１に圧送することで、簡単にケーシング管３の下部の周囲の地盤１を割裂させ、真空吸引と揚水により割裂により生じた目詰まり粒子を吸引除去し、これを繰り返すことで通水がスムーズとなる割裂通水路を形成して地盤改質ができるものである。
【０００９】
また、ケーシング管３下部の周囲の地盤１を加圧水により割裂して割裂通水路を形成するように周囲の地盤１を改質するに当たって、開閉弁６を有する揚水管７の下端部に揚水ポンプ８を設けて揚水手段４を構成し、この揚水管７を上端部が閉塞されたケーシング管３に貫挿して揚水ポンプ８をケーシング管３内の下部に配置し、ケーシング管３の上端部にバキュームポンプ９に接続したエア弁１０を有するバキューム管１１を接続すると共にケーシング管３内に加圧水を供給するための送水ポンプ１２に接続した送水弁１３を有する送水管１４を接続し、開閉弁６とエア弁１０とを閉にした状態で送水弁１３を開にして送水ポンプ１２により地盤１に埋設したケーシング管３内に加圧水を圧送することで通水部２から加圧水を地盤１中に圧送してケーシング管３下部の周囲の地盤１を加圧水により割裂する加圧水圧送工程を実施し、次に、送水ポンプ１２の運転を停止して送水弁１３を閉じると共に開閉弁６とエア弁１０とを開にした状態で揚水ポンプ８とバキュームポンプ９を運転してバキューム吸引で地盤１中の地下水と共に地盤１中の目詰まり粒子をケーシング管３内に吸引しつつ揚水ポンプ８により揚水する洗浄用揚水工程を実施し、上記加圧水圧送工程と、洗浄用揚水工程とを交互に繰り返すことを特徴とすることも好ましい。このような方法を採用することで、開閉弁６と揚水ポンプ８、エア弁１０とバキュームポンプ９、送水ポンプ１２と送水弁１３の開・閉や運転・停止を操作するのみで、加圧水の地盤１への圧送と、加圧水の地盤１への圧送により飽和状態となった地盤１の地下水を真空で吸引すると共に揚水手段４により揚水することを交互に繰り返して地盤１を改質することができるものである。
【００１０】
また、ケーシング管３下部の周囲の地盤１を加圧水により割裂して割裂通水路を形成するように周囲の地盤１を改質するに当たって、開閉弁６を有する揚水管７の下端部に揚水ポンプ８を設けて揚水手段４を構成し、この揚水管７を上端部が閉塞されたケーシング管３に貫挿して揚水ポンプ８をケーシング管３内の下部に配置し、ケーシング管３の上端部にエア抜き弁５を有するエア抜き部１６を接続すると共にケーシング管３内に加圧水を供給するための送水ポンプ１２に接続した送水弁１３を有する送水管１４を接続し、開閉弁６を閉、エア抜き弁５を開にした状態で送水弁１３を開にして送水ポンプ１２によりケーシング管３内に加圧水を圧送して地盤１に埋設したケーシング管３内を加圧水で満たした状態でエア抜き弁５を閉じ、引き続き送水ポンプ１２によりケーシング管３内に加圧水を圧送することで通水部２から加圧水を地盤１中に圧送してケーシング管３下部の周囲の地盤１を加圧水により割裂する加圧水圧送工程を実施し、次に、送水ポンプ１２の運転を停止して送水弁１３を閉じると共にエア抜き弁５を閉じた状態で開閉弁６を開き揚水ポンプ８を運転してケーシング管３内の水を揚水することでケーシング管３の上部に真空空間を形成し、このケーシング管３内に発生した真空による吸引で地盤１中の地下水と共に地盤１中の目詰まり粒子をケーシング管３内に吸引しつつ揚水ポンプ８により揚水する洗浄用揚水工程を実施し、上記加圧水圧送工程と洗浄用揚水工程とを交互に繰り返すことを特徴とすることも好ましい。開閉弁６と揚水ポンプ８、エア抜き弁５、送水ポンプ１２と送水弁１３の開・閉や運転・停止を操作するのみで、加圧水の地盤１への圧送と、加圧水の地盤１への圧送により飽和状態となった地盤１の地下水を真空で吸引すると共に揚水手段４により揚水することを交互に繰り返して地盤１を改質することができるものであり、特に、バキュームポンプを用いなくても簡単な方法でケーシング管３内の上部を真空にできて地下水、目詰まり粒子を真空吸引によりケーシング管３内に吸引することができるものである。
【００１１】
【発明の実施の形態】
以下、本発明を添付図面に示す実施形態に基づいて説明する。
【００１２】
本発明においては、地下工事のために地盤を掘削したり、地盤改良を行うために該当地盤１の地下水を揚水するに当たって、まず地盤１にケーシング管３を埋設し、次に、ケーシング管３の下端部に設けた通水部２から加圧水を地盤１中に圧送してケーシング管３下部の周囲の地盤１を加圧水により割裂して割裂通水路を形成するように周囲の地盤１を改質する地盤改質工程を実施する。このようにケーシング管３の周囲の地盤１の地盤改質を行って、地下水がケーシング管３の下部の周囲の地盤をスムーズに流れて通水部２からケーシング管３内に集水できるようにし、この地盤改質工程を実施した後に、揚水手段４により周辺の地盤１に形成した割裂通水路を介して地下水を通水部２からケーシング管３内に流入させて揚水する本揚水工程を実施するものである。
【００１３】
図１乃至図４には本発明の一実施形態が示してある。地盤１中に埋設されるケーシング管３は鋼管からなり、ケーシング管３の下端部の下部筒部３ａの外周には隙間２０を介して下部筒部３ａを囲む上下方向に長いストレーナ部２１が設けてあり、下部筒部３ａの下端部には砂溜まり部２２が設けてある。下部筒部３ａには通水部２が設けてある。また、ストレーナ部２１は例えば枠体の外周に所定間隔で隙間を形成するような鋼線が巻かれ略円筒形状をしたものからなり、上下方向に多数形成された隙間が水通過部２３となって地下水を流入させることができるようになっている。なお、ストレーナ部部２１としては上記のように鋼線を巻いて構成したものにのみ限定されず、水通過部２３となる多数の孔を開けた孔あき筒により構成してもよい。いずれの場合もストレーナ部２１の最上部の水通過部２３は通水部２よりも上方に位置している。
【００１４】
ケーシング管３の上端部には蓋体２４を取付けてケーシング管３の上開口を閉塞してある。また、開閉弁６を有する揚水管７の下端部に揚水ポンプ８を設けて揚水手段４を構成し、この揚水管７を上端部が閉塞されたケーシング管３に貫挿して揚水ポンプ８をケーシング管３内の下部に配置してある。添付図面に示す実施形態においては、揚水管７が蓋体２４を貫挿して取付けてある。また、ケーシング管３の上端部にバキュームポンプ９に接続したエア弁１０を有するバキューム管１１を接続すると共にケーシング管３内に加圧水を供給するための送水ポンプ１２に接続した送水弁１３を有する送水管１４を接続してある。添付図面に示す実施形態では蓋体２４部分にバキューム管１１、送水管１４の端部を取付けてバキューム管１１、送水管１４の端部をケーシング管３内に開口している。ここで、送水管１４の端部のケーシング管３内における開口位置はバキューム管１１のケーシング管３内における開口位置よりも下方に位置している。
【００１５】
上記のような構成の地下水揚水装置のケーシング管３を地盤１に埋設するに当たっては、地下水を揚水しようとする地盤１にケーシング管３よりも径の大きい穿孔２５を掘削し、この穿孔２５に上記地下水揚水装置のケーシング管３を挿入するのであるが、穿孔２５の内壁とケーシング管３の外周面との間に荒砂や豆砂利等のフィルター材２６を充填し、更に穿孔２５の内壁の上部とケーシング管３の外周面の上部との間にセメントモルタルやベントナイトモルタル等のシール材２７を充填してシールしてある。ここで、穿孔２５の内壁の上部と外管３の外周面の上部との間のシールをするに当たっては、穿孔２５の内壁の上部とケーシング管３の外周面の上部との間のバルーンを入れて該バルーンを膨らませる等の他の手段によりシールするようにしてもよいものである。
【００１６】
上記のように地下水揚水装置のケーシング管３を地盤１に埋設して地盤１中の地下水を揚水手段４により揚水するのであるが、本発明においては揚水手段４により本揚水するに先立って、まずケーシング管３の下部の周囲の地盤１の地盤改質を行って地下水が通水しやすいようにする。
【００１７】
地盤改質を行うに当たっては、まず、図１に示すように、開閉弁６とエア弁１０とを閉にした状態で送水弁１３を開にして貯水タンク２８内の水を送水ポンプ１２により地盤１に埋設したケーシング管３内に圧送し、ケーシング管３の下端部の通水部２から水通過部２３を経て加圧水を地盤１中に圧送する。このようにして加圧水をケーシング管３の周囲の地盤１中に強制的に圧送することで、ケーシング管３下部の周囲の地盤１を加圧水により割裂する加圧水圧送工程を実施する。この場合、シール材２７でシールしてあるので、加圧水がケーシング管３の外面に沿って上昇して地上に噴き出すことがない。
【００１８】
次に、図２に示すように、送水ポンプ１２の運転を停止して送水弁１３を閉じると共に開閉弁６とエア弁１０とを開にした状態で揚水ポンプ８とバキュームポンプ９を運転してバキューム吸引により上記加圧水圧送工程により飽和状態となった地盤１の地下水を一気に吸引し、地盤１中の地下水と共に割裂により生じた地盤１中の目詰まり粒子を水通過部２３、通水部２を経てケーシング管３内に吸引しつつ揚水ポンプ８により揚水する洗浄用揚水工程を実施する。この場合、シール材２７でシールしているので、ケーシング管３の外面に沿って地上の空気が吸い込まれることがない。
【００１９】
このようにして加圧水の圧送により飽和状態となった地盤１中の地下水を揚水すると、同様にして上記加圧水圧送工程、洗浄用揚水工程を交互に実施する。
【００２０】
ここで、地盤１への加圧水の圧送によりケーシング管３の下部の周囲に多数の割裂通水路を形成するとともに加圧水の圧送により割裂通水路が形成される際に生じた目詰まり粒子をバキューム吸引により強制的に吸引して揚水することを交互に形成することで、「水みち」となる割裂通水路は次第に地下水がスムーズに流れやすいように成長し、また、目詰まり粒子が除去されることでよりいっそう地下水がスムーズに流れやすいようになる。
【００２１】
上記のようにして、ケーシング管３下部の周囲の地盤１を地下水がスムーズに通水しやすいように改質する地盤改質工程が終わると、次に、揚水手段４により周辺の地盤１に形成した割裂通水路を介して地下水を通水部２からケーシング管３内に流入させて揚水する本揚水工程を実施する。
【００２２】
本揚水工程は以下のようにして行う。すなわち、図３に示すように、送水ポンプ１２の運転を停止して送水弁１３を閉じ、この状態で開閉弁６とエア弁１０とを開にし、揚水ポンプ８とバキュームポンプ９を運転し、水頭差とバキューム吸引により地盤１の地下水を上下方向に長いストレーナ部２１の上下方向に多数設けた水通過部２３、隙間２０、ケーシング管３の下端部の通水部２を経てケーシング管３内に集水し、ケーシング管３内に集水した地下水を揚水ポンプ８により揚水するものである。この本揚水工程において、既に前段の地盤改質工程においてケーシング管３の下部周囲の地盤１に割裂通水路を形成しているので、地下水は形成された割裂通水路を通ってスムーズにケーシング管３の下端部の通水部２に流れ、水頭差とバキューム吸引によるケーシング管３内への集水が効果的に行われ、このようにケーシング管３内への集水が効果的に行われるので、揚水ポンプ８による揚水がロスなく効率的に行えることになる。
【００２３】
なお、ストレーナ部２１を設けたものにおいては、地下水位がストレーナ部２１の上端部（最上端の水通過部２３）よりも下方に位置したとしても、最上端の水通過部２３が通水部２よりも上方に位置しているのでストレーナ部２１の上端部から隙間２０内に進入した地盤１中のエアは通水部２からケーシング管３内に進入することができず、隙間２０の上部に集まることになり、地下水の水位の低下によりケーシング管３内にエアが流れ込むのを防止し、これによりケーシング管３内における減圧状態が破れることがなく、バキューム吸引によってケーシング管３内に地下水を集水することが継続して行えるものである。
【００２４】
次に、本発明の他の実施形態を図５乃至図９に基づいて説明する。
【００２５】
ケーシング管３の上端部には蓋体２４を取付けてケーシング管３の上開口を閉塞してある。また、開閉弁６を有する揚水管７の下端部に揚水ポンプ８を設けて揚水手段４を構成し、この揚水管７を上端部が閉塞されたケーシング管３に貫挿して揚水ポンプ８をケーシング管３内の下部に配置してある。添付図面に示す実施形態においては、揚水管７が蓋体２４を貫挿して取付けてある。また、ケーシング管３の上端部にエア抜き弁５を有するエア抜き部１６を接続すると共にケーシング管３内に加圧水を供給するための送水ポンプ１２に接続した送水弁１３を有する送水管１４を接続してある。添付図面に示す実施形態では蓋体２４部分にエア抜き部１６、送水管１４の端部を取付けてエア抜き部１６、送水管１４の端部をケーシング管３内に開口している。ここで、送水管１４の端部のケーシング管３内における開口位置はエア抜き部１６のケーシング管３内における開口位置よりも下方に位置している。また、ケーシング管３の下端部の下部筒部３ａには通水部２が設けてある。また、図５乃至図９に示す実施形態では前述の実施形態と同様にケーシング管３の下端部の下部筒部３ａの外周には隙間２０を介して下部筒部３ａを囲む上下方向に長いストレーナ部２１が設けてある。
【００２６】
上記のような構成の地下水揚水装置のケーシング管３を前述の実施形態と同様にして地盤１に埋設する。
【００２７】
そして、地盤１中の地下水を揚水手段４により本揚水するに先立って、まずケーシング管３の下部の周囲の地盤１の地盤改質を行って地下水が通水しやすいようにする。
【００２８】
本実施形態において地盤改質を行うに当たっては、まず、図５に示すように、開閉弁６を閉、エア抜き弁５を開にした状態で送水弁１３を開にして送水ポンプ１２によりケーシング管３内に加圧水を圧送し、図６に示すように地盤１に埋設したケーシング管３内が加圧水で満たされると、図７のようにエア抜き弁５を閉じ、引き続き送水ポンプ１２によりケーシング管３内に加圧水を圧送する。このようにして加圧水をケーシング管３の周囲の地盤１中に強制的に圧送することで、ケーシング管３下部の周囲の地盤１を加圧水により割裂する加圧水圧送工程を実施する。
【００２９】
次に、図８のように送水ポンプ１２の運転を停止して送水弁１３を閉じると共にエア抜き弁５を閉じ、この状態で揚水ポンプ８を運転してケーシング管３内の水を揚水すると、ケーシング管３内に満たされていた水が揚水ポンプ８で揚水されることでケーシング管３の上部に真空空間１５が形成される。すると、上記ケーシング管３内に発生した真空による吸引で上記圧送されて地盤１中に飽和状態となった地下水と共に地盤１中の目詰まり粒子がケーシング管３内に吸引されるので、この間揚水ポンプ６の運転を継続することで、ケーシング管３内に吸引された地下水と目詰まり粒子とが揚水ポンプ６により揚水され、これによりケーシング管３内は上部に真空空間１５を形成したままケーシング管３内に地下水と目詰まり物質とを吸引し続けることになる。これが洗浄用揚水工程である。
【００３０】
このようにして加圧水の圧送により飽和状態となった地盤１中の地下水を揚水すると、同様にして上記加圧水圧送工程、洗浄用揚水工程を交互に実施する。ここで２回目以降の加圧水圧送工程においてはエア抜き弁５は閉じたまま、開閉弁６を閉にした状態で送水弁１３を開にして送水ポンプ１２によりケーシング管３内に加圧水を圧送する。すると、地盤１に埋設したケーシング管３内が加圧水で満たされるので、引き続き送水ポンプ１２によりケーシング管３内に加圧水を圧送することにより加圧水をケーシング管３の周囲の地盤１中に強制的に圧送してケーシング管３下部の周囲の地盤１を割裂通水路を形成する加圧水圧送工程を実施することができる。
【００３１】
このようにして、地盤１への加圧水の圧送によりケーシング管３の下部の周囲に多数の割裂通水路を形成するとともに加圧水の圧送により割裂通水路が形成される際に生じた目詰まり粒子をバキューム吸引により強制的に吸引して揚水することを交互に形成することで、「水みち」となる割裂通水路は次第に地下水がスムーズに流れやすいように成長し、また、目詰まり粒子が除去されることでよりいっそう地下水がスムーズに流れやすいようになる。
【００３２】
上記のようにして、ケーシング管３下部の周囲の地盤１を地下水がスムーズに通水しやすいように改質する地盤改質工程が終わると、次に、揚水手段４により周辺の地盤１に形成した割裂通水路を介して地下水を通水部２からケーシング管３内に流入させて揚水する本揚水工程を実施する。
【００３３】
本揚水工程は以下のようにして行う。すなわち、地盤改質工程の最終段階の洗浄用揚水工程をそのまま引き続いて図９に示すように本揚水工程に移行できるものであり、洗浄用揚水工程と同様の作用により本揚水工程により揚水することができるものである。この本揚水工程において、既に前段の地盤改質工程においてケーシング管３の下部周囲の地盤１に割裂通水路を形成しているので、地下水は形成された割裂通水路を通ってスムーズにケーシング管３の下端部の通水部２に流れるので、水頭差とバキューム吸引によるケーシング管３内への集水が効果的に行われ、このようにケーシング管３内への集水が効果的に行われるので、揚水ポンプ８による揚水がロスなく効率的に行えることになる。ところで、本揚水工程で地下水の水位が一時的に低下してきてケーシング管３内の下端部の通水部２からエアがケーシング管３内に流入するとケーシング管３の上部の空間の減圧度が低下するが、このまま揚水ポンプ８の運転を継続して揚水してもよいが、ケーシング管３の上部の空間の減圧度が低下すると、真空引きによる地下水のケーシング管３内への吸引力が低下するので、このような場合には開閉弁６を閉、エア抜き弁５を開にした状態で送水弁１３を開にして送水ポンプ１２によりケーシング管３内に加圧水を圧送してケーシング管３内を加圧水で満たし、その後、送水ポンプ１２の運転を停止して送水弁１３を閉じると共にエア抜き弁５を閉じ、この状態で揚水ポンプ８を運転してケーシング管３内の水を揚水することで、ケーシング管３内に満たされていた水が揚水ポンプ８で揚水してケーシング管３の上部に真空空間１５を形成することができるので、この状態のまま継続して揚水ポンプ８を運転することで、地下水をケーシング管３内に真空吸引しながら揚水することができるものである。
【００３４】
本実施形態においては、バキュームポンプを用いなくても簡単な方法でケーシング管３内の上部を真空にできて地下水、目詰まり粒子を真空吸引によりケーシング管３内に吸引することができるものである。
【００３５】
また、上記各実施形態においては、ケーシング管３下部の周囲の地盤１を加圧水により割裂して割裂通水路を形成するように周囲の地盤１を改質するに当たって、加圧水の地盤１への圧送と、加圧水の地盤１への圧送により飽和状態となった地盤１の地下水を真空で吸引すると共に揚水手段４により揚水することを交互に繰り返して地盤１を改質するようにした例を示したが、ケーシング管３下部の周囲の地盤１を加圧水により割裂して割裂通水路を形成するように周囲の地盤１を改質するに当たって、加圧水を連続してケーシング管３下部の周囲の地盤１に圧送することのみでケーシング管３下部の周囲の地盤１に「水みち」となる割裂通水路を形成するようにしてもよい。例えば、本実施形態においては図１のように開閉弁６とエア弁１０とを閉にした状態で送水弁１３を開にして送水ポンプ１２により地盤１に埋設したケーシング管３内に加圧水を圧送し、ケーシング管３の下端部の通水部２から水通過部２３を経て加圧水を地盤１中に圧送する。この加圧水圧送工程のみを継続して実行することで、ケーシング管３下部の周囲の地盤１を加圧水により割裂して割裂通水路を次第に成長させて地下水がスムーズに流れる「水みち」となる割裂通水路を形成するものである。
【００３６】
上記のように加圧水圧送工程のみで簡単にケーシング管３の下部の周囲に割裂通水路を形成して地盤改質ができるものである。
【００３７】
このようにしてケーシング管３の下部の周囲の地盤改質を行った後、上記と同様にして揚水手段により本揚水を実行するものである。
【００３８】
そして、上記したいずれの実施形態においても、地盤改質工程とこれに続く本揚水工程とを同一の地下水揚水装置により行うことで、共通の装置で簡単に地盤改質と揚水とができるものであって、コスト的に有利であり、工期も短縮できることになる。
【００３９】
【発明の効果】
上記のように本発明の請求項１記載の発明にあっては、ケーシング管の下端部の下部筒部に通水部を設けると共に該下部筒部の外周に隙間を介して下部筒部を囲む多数の水通過部を有する上下方向に長いストレーナ部を設け、上記ケーシング管を地盤に埋設して該ケーシング管の下端部に設けたストレーナ部の多数の水通過部、下部筒部とストレーナ部との間の隙間を介して通水部から地下水を流入させて流入した地下水を揚水手段により揚水するに先立って、ケーシング管の下端部に設けた上記通水部から加圧水を上記下部筒部とストレーナ部との間の隙間、ストレーナ部の多数の水通過部を介して地盤中に圧送してケーシング管下部の周囲の地盤を加圧水により割裂して割裂通水路を形成するように周囲の地盤を改質する地盤改質工程を実施し、この地盤改質工程を実施した後で、揚水手段により周辺の地盤に形成した割裂通水路を介して地下水をストレーナ部の多数の水通過部、下部筒部とストレーナ部との間の隙間を経て通水部からケーシング管内に流入させて揚水する本揚水工程を実施するので、本揚水を実行する前に、あらかじめケーシング管の下部の周囲の地盤に割裂通水路を形成するように周囲の地盤を改質できて、本揚水に当たって地下水をあらかじめ形成した割裂通水路を介して通水部からケーシング管の内部にスムーズに集水でき、ケーシング管の下部の周囲の地盤が通水しにくい地質の場合や地盤における地下水が存在する部分と通水部との位置が一致していない場合であっても、効果的にケーシング管内に集水して効率的に揚水手段により本揚水ができるものであり、特に、ケーシング管の下部の下部筒部に設けた通水部、隙間、ストレーナ部の多数の水通過部を介して加圧水を地盤中に圧送して割裂通水路を形成し、地下水を上記ストレーナ部の多数の水通過部、隙間、通水部を介して流入させて揚水するので、地盤改質工程とこれに続く本揚水工程とを同一の地下揚水装置により行うことができ、共通の装置で簡単に地盤改質と揚水とができ、コスト的に有利である。更に、ケーシング管下部の周囲の地盤を加圧水により割裂して割裂通水路を形成するように周囲の地盤を改質するに当たって、加圧水の地盤への圧送と、加圧水の地盤への圧送により飽和状態となった地盤の地下水を真空で吸引すると共に揚水手段により揚水すること、とを交互に繰り返して地盤を改質するので、本揚水を実行する前に、あらかじめケーシング管の下部の周囲の地盤に割裂通水路を形成するように周囲の地盤を改質するに当たって、加圧水を連続してケーシング管下部の周囲の地盤に圧送することで、簡単にケーシング管の下部の周囲の地盤を割裂させ、真空吸引と揚水により割裂により生じた目詰まり粒子を吸引除去し、これを繰り返すことで目詰まり粒子が除去され通水がスムーズとなる割裂通水路を簡単に形成して地盤改質ができるものである。
【００４２】
また、請求項２記載の発明にあっては、上記請求項１記載の発明の効果に加えて、開閉弁とエア弁とを閉にした状態で送水弁を開にして送水ポンプにより地盤に埋設したケーシング管内に加圧水を圧送することで通水部から加圧水を地盤中に圧送してケーシング管下部の周囲の地盤を加圧水により割裂する加圧水圧送工程を実施し、次に、送水ポンプの運転を停止して送水弁を閉じると共に開閉弁とエア弁とを開にした状態で揚水ポンプとバキュームポンプを運転してバキューム吸引で地盤中の地下水と共に地盤中の目詰まり粒子をケーシング管内に吸引しつつ揚水ポンプにより揚水する洗浄用揚水工程を実施し、上記加圧水圧送工程と、洗浄用揚水工程とを交互に繰り返すので、開閉弁と揚水ポンプ、エア弁とバキュームポンプ、送水ポンプと送水弁の開・閉や運転・停止を操作するのみで、加圧水の地盤への圧送と、加圧水の地盤への圧送により飽和状態となった地盤の地下水を真空で吸引すると共に揚水手段により揚水することを交互に繰り返して地盤を改質することができ、目詰まり粒子が除去され通水がスムーズとなる割裂通水路を簡単に形成して地盤改質ができるものである。
【００４３】
また、請求項３記載の発明にあっては、上記請求項１記載の発明の効果に加えて、開閉弁を閉、エア抜き弁を開にした状態で送水弁を開にして送水ポンプによりケーシング管内に加圧水を圧送して地盤に埋設したケーシング管内を加圧水で満たした状態でエア抜き弁を閉じ、引き続き送水ポンプによりケーシング管内に加圧水を圧送することで通水部から加圧水を地盤中に圧送してケーシング管下部の周囲の地盤を加圧水により割裂する加圧水圧送工程を実施し、次に、送水ポンプの運転を停止して送水弁を閉じると共にエア抜き弁を閉じた状態で開閉弁を開き揚水ポンプを運転してケーシング管内の水を揚水することでケーシング管の上部に真空空間を形成し、このケーシング管内に発生した真空による吸引で地盤中の地下水と共に地盤中の目詰まり粒子をケーシング管内に吸引しつつ揚水ポンプにより揚水する洗浄用揚水工程を実施し、上記加圧水圧送工程と、洗浄用揚水工程とを交互に繰り返すので、開閉弁と揚水ポンプ、エア抜き弁、送水ポンプと送水弁の開・閉や運転・停止を操作するのみで、簡単な方法で加圧水の地盤への圧送と、加圧水の地盤への圧送により飽和状態となった地盤の地下水を真空で吸引すると共に揚水手段により揚水することを交互に繰り返して地盤を改質することができるものであり、特に、バキュームポンプを用いなくても簡単な方法でケーシング管内の上部を真空にできて地下水、目詰まり粒子を真空吸引によりケーシング管内に吸引することができるものである。
【図面の簡単な説明】
【図１】本発明の一実施形態の地盤改質工程の順序を示す説明図である。
【図２】同上の地盤改質工程の順序を示す説明図である。
【図３】同上の本揚水工程の説明図である。
【図４】同上に用いるケーシング管の一例の下部の拡大断面図である。
【図５】本発明の他の実施形態の地盤改質工程の順序を示す説明図である。
【図６】同上の地盤改質工程の順序を示す説明図である。
【図７】同上の地盤改質工程の順序を示す説明図である。
【図８】同上の地盤改質工程の順序を示す説明図である。
【図９】同上の地盤改質工程の順序を示す説明図である。
【符号の説明】
１地盤
２通水部
３ケーシング管
４揚水手段
５エア抜き弁
６開閉弁
７揚水管
８揚水ポンプ
９バキュームポンプ
１０エア弁
１１バキューム管
１２送水ポンプ
１３送水弁
１４送水管[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for pumping up groundwater to lower the groundwater level when excavating the ground for underground construction or performing ground improvement.
[0002]
[Prior art]
Conventionally, when excavating the ground for underground construction or performing ground improvement, the groundwater is pumped to lower the groundwater level. Thus, groundwater is pumped and the groundwater level is lowered, so that the moisture content of the target soil is reduced, and excavation work and treatment of excavated soil can be easily performed.
[0003]
When pumping up the groundwater, it is performed by pumping up the groundwater that has flowed in by flowing the groundwater from the water flow section provided at the lower end of the casing pipe buried in the ground, and as a pumping method, for example, Vacuum that makes it possible to further reduce the groundwater level by reducing the pressure in the well by using the deep well method that drains water using the head difference between the natural water level and the water level in the well, or by providing pressure reduction means in the deep well device. The deep well method is known. As another conventional example, Japanese Patent Laid-Open No. 2000-27170 is known. In this Japanese Patent Laid-Open No. 2000-27170, a strainer device is provided at the lower end of the casing tube, and ground water is collected in the casing tube through the strainer device by a vacuum force generated by depressurizing the inside of the casing tube with a water head difference and a depressurizing means. In this way, the groundwater collected in the casing pipe through the strainer device is pumped up by the pump.
[0004]
However, in any of the above conventional examples, the casing pipe is simply buried in the ground and the groundwater is pumped by the above-described methods. However, when the casing pipe is buried in the ground, the lower end of the casing pipe is used. The water passing part provided in the section does not necessarily match the part where water exists in the ground, but rather the water passing part at the lower end part of the casing pipe and the part where water exists in the ground may not match. In many cases, the geology around the water passing portion of the casing pipe is difficult to pass. For this reason, when collecting groundwater into the casing pipe from the water passing portion at the lower end of the casing pipe by each of the above methods (by water head difference or water head difference and vacuum force), the ground water is collected around the lower part of the casing pipe. There was a problem that the water collection effect was poor because it was difficult to flow smoothly to the water passage side after passing through the ground.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and prior to pumping up the groundwater collected in the casing pipe embedded in the ground, the groundwater around the casing pipe is smoothly grounded toward the water supply side in advance. It is an object of the present invention to provide a groundwater pumping method capable of collecting and pumping water effectively by improving the water so that it can flow easily.
[0006]
[Means for Solving the Problems]
  In order to solve the above problems, the groundwater pumping method according to the present invention is:The lower tube portion 3a at the lower end portion of the casing tube 3 is provided with a water passage portion 2 and has a large number of vertically long water passage portions 23 surrounding the lower tube portion 3a via a gap 20 on the outer periphery of the lower tube portion 3a. A strainer portion 21 is provided, and the casing tube 3 is embedded in the ground 1 toProvided at the lower end of the casing tube 3Through a large number of water passage portions 23 of the strainer portion 21 and gaps 20 between the lower cylindrical portion 3a and the strainer portion 21.Prior to pumping in the groundwater from the water flow section 2 by the pumping means 4, it was provided at the lower end of the casing pipe 3.the abovePressurized water from the water passing part 2Through the gap 20 between the lower cylindrical portion 3a and the strainer portion 21, and a large number of water passage portions 23 of the strainer portion 21.A ground reforming step is performed in which the surrounding ground 1 is reformed so as to form a split water passage by pressure-feeding into the ground 1 and splitting the surrounding ground 1 below the casing tube 3 with pressurized water. After carrying out the process, the groundwater is discharged through the split water channel formed in the surrounding ground 1 by the pumping means 4.Through a large number of water passage portions 23 of the strainer portion 21 and gaps 20 between the lower cylindrical portion 3a and the strainer portion 21.The main pumping process of pumping water by flowing into the casing pipe 3 from the water passing portion 2 is performed.In the method, as described above, when the surrounding ground 1 at the lower part of the casing tube 3 is split with pressurized water to reform the surrounding ground 1 so as to form a split water passage, Then, the ground 1 in the ground 1 saturated by the pumping of the pressurized water to the ground 1 is sucked in vacuum and pumped by the pumping means 4 alternately to reform the ground 1.It is characterized by this. By adopting such a method, before the main pumping is performed, the surrounding ground 1 is modified in advance so as to form a split water passage in the surrounding ground 1 at the lower part of the casing pipe 3, and thus After the ground 1 around the lower part of the casing pipe 3 has been reformed, the groundwater collected in the casing pipe 3 by the pumping means 4 is pumped up, thereby effectively collecting the groundwater in the casing pipe 3. Water can be pumped efficiently.In particular, the split water passage is formed by pumping pressurized water into the ground 1 through the water passing portion 2 provided in the lower cylindrical portion 3a at the lower portion of the casing tube 3, the gap 20, and the many water passage portions 23 of the strainer portion 21. In addition, since the groundwater is pumped by flowing in through the numerous water passage portions 23, the gaps 20, and the water flow portion 2 of the strainer portion 21, the ground reforming step and the subsequent main pumping step are the same underground pumping. In addition, the ground 1 around the lower part of the casing pipe 3 is split with pressurized water to reform the surrounding ground 1 so as to form a split water passage. Since the ground 1 is reformed by alternately sucking the ground water of the ground 1 saturated by the pumping of the pressurized water and the pumped water into the ground 1 and pumping the water by the pumping means 4 alternately, Before running When reforming the surrounding ground 1 so as to form a split water passage in the surrounding ground 1 at the lower part of the casing pipe 3, pressurized water is continuously pumped to the surrounding ground 1 at the lower part of the casing pipe 3. The ground 1 around the lower part of the casing tube 3 is easily split, and the clogging particles generated by the splitting are sucked and removed by vacuum suction and pumping up. By repeating this, the splitting water passage that makes the water flow smooth is formed. Therefore, the ground can be improved.
[0009]
Further, in reforming the surrounding ground 1 so as to split the surrounding ground 1 under the casing pipe 3 with pressurized water to form a split water passage, a pumping pump 8 is provided at the lower end of the lifting pipe 7 having the on-off valve 6. The pumping means 4 is constructed, the pumping pipe 7 is inserted into the casing pipe 3 whose upper end is closed, the pumping pump 8 is arranged in the lower part of the casing pipe 3, and the vacuum is formed at the upper end of the casing pipe 3. A vacuum pipe 11 having an air valve 10 connected to a pump 9 is connected and a water supply pipe 14 having a water supply valve 13 connected to a water supply pump 12 for supplying pressurized water into the casing pipe 3 is connected. With the air valve 10 closed, the water supply valve 13 is opened, and the water supply pump 12 pumps the pressurized water into the casing pipe 3 embedded in the ground 1 to pressurize the pressurized water from the water passing portion 2 into the ground 1. Then, a pressurized water pumping process for splitting the ground 1 around the lower part of the casing tube 3 with pressurized water is performed, and then the operation of the water pump 12 is stopped to close the water feed valve 13 and the on-off valve 6 and the air valve 10 are connected. The pumping pump 8 and the vacuum pump 9 are operated in the open state, and the pumping water for washing is pumped by the pumping pump 8 while sucking the clogged particles in the ground 1 into the casing pipe 3 together with the groundwater in the ground 1 by vacuum suction. It is also preferable to carry out the process and to repeat the above-described pressurized water pumping process and the washing pumping process alternately. By adopting such a method, the open / close valve 6 and the pump 8, the air valve 10 and the vacuum pump 9, the water pump 12 and the water valve 13 can be opened / closed and operated / stopped. The ground 1 can be modified by alternately sucking the ground water of the ground 1 saturated by the pumping to the ground 1 and the pressurized water to the ground 1 and pumping the ground water by the pumping means 4 alternately. Is.
[0010]
Further, in reforming the surrounding ground 1 so as to split the surrounding ground 1 under the casing pipe 3 with pressurized water to form a split water passage, a pumping pump 8 is provided at the lower end of the lifting pipe 7 having the on-off valve 6. The pumping means 4 is provided, the pumping pipe 7 is inserted into the casing pipe 3 whose upper end is closed, the pumping pump 8 is arranged in the lower part of the casing pipe 3, and air is supplied to the upper end of the casing pipe 3. An air vent 16 having a vent valve 5 is connected and a water feed pipe 14 having a water feed valve 13 connected to a water feed pump 12 for supplying pressurized water into the casing pipe 3 is connected, the on-off valve 6 is closed, and air is vented. With the valve 5 open, the water supply valve 13 is opened and the water pump 12 pumps pressurized water into the casing pipe 3 to fill the casing pipe 3 embedded in the ground 1 with the pressurized water. Close, pull Subsequently, a pressurized water pumping process is performed in which pressurized water is pumped into the casing pipe 3 by the water pump 12 to pump the pressurized water from the water passing portion 2 into the ground 1 and split the ground 1 around the lower portion of the casing pipe 3 with the pressurized water. Next, the operation of the water supply pump 12 is stopped, the water supply valve 13 is closed and the air vent valve 5 is closed, and the open / close valve 6 is opened and the pumping pump 8 is operated to pump the water in the casing pipe 3. A vacuum space is formed in the upper part of the casing tube 3, and the pumping pump 8 is configured to suck the clogged particles in the ground 1 into the casing tube 3 together with the groundwater in the ground 1 by suction generated by the vacuum generated in the casing tube 3. It is also preferable that a washing pumping process for pumping is performed, and the pressurized water pumping process and the cleaning pumping process are alternately repeated. By simply opening / closing or operating / stopping the open / close valve 6 and the pump 8, the air vent valve 5, the water pump 12 and the water valve 13, the pressurized water is pumped to the ground 1 and the pressurized water is pumped to the ground 1. It is possible to reform the ground 1 by alternately sucking the ground water of the ground 1 saturated by the vacuum and pumping it by the pumping means 4, and in particular, without using a vacuum pump. The upper part of the casing tube 3 can be evacuated by a simple method, and groundwater and clogged particles can be sucked into the casing tube 3 by vacuum suction.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on embodiments shown in the accompanying drawings.
[0012]
In the present invention, when excavating the ground for underground construction or pumping the ground water of the ground 1 to improve the ground, the casing pipe 3 is first buried in the ground 1 and then the casing pipe 3 The surrounding ground 1 is reformed so that pressurized water is pumped into the ground 1 from the water flow section 2 provided at the lower end portion, and the ground 1 around the lower portion of the casing pipe 3 is split with the pressurized water to form a split water passage. Implement ground improvement process. In this way, the ground modification of the ground 1 around the casing pipe 3 is performed so that the groundwater can smoothly flow through the ground around the lower part of the casing pipe 3 to collect water from the water passing portion 2 into the casing pipe 3. After carrying out this ground reforming step, the main pumping step of pumping the groundwater through the splitting water passage formed in the surrounding ground 1 by the pumping means 4 from the water-passing part 2 into the casing pipe 3 is carried out. To do.
[0013]
1 to 4 show an embodiment of the present invention. The casing pipe 3 embedded in the ground 1 is made of a steel pipe, and a vertically long strainer portion 21 is provided on the outer periphery of the lower cylindrical portion 3a at the lower end portion of the casing pipe 3 with a gap 20 interposed between the lower cylindrical portion 3a. A sand reservoir 22 is provided at the lower end of the lower cylindrical portion 3a. A water passage portion 2 is provided in the lower cylindrical portion 3a. In addition, the strainer portion 21 is made of, for example, a substantially cylindrical shape in which a steel wire that forms a gap at a predetermined interval is wound around the outer periphery of the frame body, and a plurality of gaps formed in the vertical direction serve as the water passage portion 23. The groundwater can be introduced. Note that the strainer portion 21 is not limited to the one configured by winding the steel wire as described above, and may be configured by a perforated tube having a large number of holes serving as the water passage portion 23. In any case, the uppermost water passage portion 23 of the strainer portion 21 is located above the water passage portion 2.
[0014]
A lid 24 is attached to the upper end of the casing tube 3 to close the upper opening of the casing tube 3. Further, a pumping pump 8 is provided at the lower end of the pumping pipe 7 having the opening / closing valve 6 to constitute the pumping means 4, and the pumping pump 8 is inserted into the casing pipe 3 closed at the upper end so that the pumping pump 8 is installed in the casing. It is arranged in the lower part in the tube 3. In the embodiment shown in the accompanying drawings, the pumping pipe 7 is attached through the lid body 24. Further, a vacuum pipe 11 having an air valve 10 connected to a vacuum pump 9 is connected to the upper end portion of the casing pipe 3 and a water supply valve 13 connected to a water supply pump 12 for supplying pressurized water into the casing pipe 3. A water pipe 14 is connected. In the embodiment shown in the accompanying drawings, the ends of the vacuum pipe 11 and the water supply pipe 14 are attached to the lid 24 portion, and the ends of the vacuum pipe 11 and the water supply pipe 14 are opened in the casing pipe 3. Here, the opening position in the casing pipe 3 at the end of the water supply pipe 14 is located below the opening position in the casing pipe 3 of the vacuum pipe 11.
[0015]
In burying the casing pipe 3 of the groundwater pumping apparatus having the above-described configuration in the ground 1, a hole 25 having a diameter larger than that of the casing pipe 3 is drilled in the ground 1 from which groundwater is to be pumped. The casing pipe 3 of the groundwater pumping device is inserted, and a filter material 26 such as rough sand or bean gravel is filled between the inner wall of the perforation 25 and the outer peripheral surface of the casing pipe 3, and the upper part of the inner wall of the perforation 25 A sealing material 27 such as cement mortar or bentonite mortar is filled between the upper portion of the outer peripheral surface of the casing tube 3 and sealed. Here, when sealing between the upper part of the inner wall of the perforation 25 and the upper part of the outer peripheral surface of the outer tube 3, a balloon between the upper part of the inner wall of the perforation 25 and the upper part of the outer peripheral surface of the casing tube 3 is inserted. The balloon may be sealed by other means such as inflating.
[0016]
As described above, the casing pipe 3 of the groundwater pumping device is buried in the ground 1 and the groundwater in the ground 1 is pumped by the pumping means 4. In the present invention, prior to the main pumping by the pumping means 4, first, Ground modification of the ground 1 around the lower part of the casing pipe 3 is performed so that groundwater can be easily passed.
[0017]
In performing ground reforming, first, as shown in FIG. 1, the water supply valve 13 is opened with the on-off valve 6 and the air valve 10 closed, and the water in the water storage tank 28 is supplied to the ground by the water supply pump 12. 1 is pumped into the casing pipe 3 embedded in 1, and pressurized water is pumped into the ground 1 through the water passage section 23 from the water passing section 2 at the lower end of the casing pipe 3. In this way, a pressurized water pumping process is performed in which the pressurized water is forcibly pumped into the ground 1 around the casing tube 3 to split the ground 1 around the lower portion of the casing tube 3 with pressurized water. In this case, since the sealing material 27 is used for sealing, the pressurized water does not rise along the outer surface of the casing tube 3 and blow out to the ground.
[0018]
Next, as shown in FIG. 2, the pumping pump 8 and the vacuum pump 9 are operated with the operation of the water pump 12 stopped, the water valve 13 closed, and the open / close valve 6 and the air valve 10 opened. The ground water of the ground 1 that has been saturated by the pressurized water pumping process by vacuum suction is sucked all at once, and the clogged particles in the ground 1 generated by splitting together with the ground water in the ground 1 are passed through the water passage part 23 and the water passing part 2. Then, a washing pumping process is performed in which pumping is performed by the pumping pump 8 while suctioning into the casing pipe 3. In this case, since the sealing material 27 is used for sealing, ground air is not sucked along the outer surface of the casing tube 3.
[0019]
When the groundwater in the ground 1 that has become saturated by pumping pressurized water in this way is pumped, the pressurized water pumping step and the cleaning pumping step are alternately performed in the same manner.
[0020]
Here, a large number of split water channels are formed around the lower portion of the casing pipe 3 by pumping pressurized water to the ground 1, and clogging particles generated when the split water channels are formed by pumping pressurized water are vacuum suctioned. By alternately forming forced suction and pumping, the split water channel that becomes the “water channel” gradually grows so that the groundwater can flow smoothly and clogging particles are removed. The groundwater will flow more smoothly.
[0021]
When the ground reforming process for reforming the ground 1 around the lower portion of the casing tube 3 so that the ground water can smoothly flow is completed as described above, the water is then formed on the surrounding ground 1 by the pumping means 4. The main pumping step of pumping up groundwater by flowing it into the casing pipe 3 from the water-passing part 2 through the split split waterway is performed.
[0022]
This pumping process is performed as follows. That is, as shown in FIG. 3, the operation of the water supply pump 12 is stopped and the water supply valve 13 is closed. In this state, the on-off valve 6 and the air valve 10 are opened, the pumping pump 8 and the vacuum pump 9 are operated, The inside of the casing pipe 3 passes through the water passage 23 provided in the vertical direction of the strainer part 21 that is long in the vertical direction by the head difference and the vacuum suction, the gap 20, and the water passing part 2 at the lower end of the casing pipe 3. The groundwater collected in the casing pipe 3 is pumped by the pumping pump 8. In this main pumping process, since the split water passage has already been formed in the ground 1 around the lower part of the casing pipe 3 in the previous ground reforming process, the ground water passes smoothly through the formed split water passage. The water flows into the water passing portion 2 at the lower end of the water, and the water collection into the casing tube 3 is effectively performed by the water head difference and the vacuum suction, and thus the water collection into the casing tube 3 is effectively performed. Thus, the pumping by the pump 8 can be efficiently performed without loss.
[0023]
In the case where the strainer portion 21 is provided, even if the groundwater level is located below the upper end portion (the uppermost water passage portion 23) of the strainer portion 21, the uppermost water passage portion 23 is the water passage portion. 2, the air in the ground 1 that has entered the gap 20 from the upper end of the strainer portion 21 cannot enter the casing pipe 3 from the water passing portion 2, and the upper portion of the gap 20. Therefore, air is prevented from flowing into the casing pipe 3 due to a drop in the water level of the groundwater, so that the decompressed state in the casing pipe 3 is not broken, and groundwater is drawn into the casing pipe 3 by vacuum suction. Water can be continuously collected.
[0024]
Next, another embodiment of the present invention will be described with reference to FIGS.
[0025]
A lid 24 is attached to the upper end of the casing tube 3 to close the upper opening of the casing tube 3. Further, a pumping pump 8 is provided at the lower end of the pumping pipe 7 having the opening / closing valve 6 to constitute the pumping means 4, and the pumping pump 8 is inserted into the casing pipe 3 closed at the upper end so that the pumping pump 8 is installed in the casing. It is arranged in the lower part in the tube 3. In the embodiment shown in the accompanying drawings, the pumping pipe 7 is attached through the lid body 24. Further, an air vent 16 having an air vent valve 5 is connected to the upper end of the casing pipe 3 and a water feed pipe 14 having a water feed valve 13 connected to a water feed pump 12 for supplying pressurized water into the casing pipe 3 is connected. It is. In the embodiment shown in the accompanying drawings, the air vent 16 and the end of the water pipe 14 are attached to the lid 24 portion, and the air vent 16 and the end of the water pipe 14 are opened in the casing tube 3. Here, the opening position in the casing pipe 3 of the end part of the water supply pipe 14 is located below the opening position in the casing pipe 3 of the air bleeding part 16. In addition, a water passing portion 2 is provided in the lower cylindrical portion 3 a at the lower end portion of the casing tube 3. Further, in the embodiment shown in FIGS. 5 to 9, a strainer that is long in the vertical direction surrounding the lower cylinder portion 3a through the gap 20 is provided on the outer periphery of the lower cylinder portion 3a at the lower end portion of the casing tube 3 in the same manner as the above-described embodiment. A portion 21 is provided.
[0026]
The casing pipe 3 of the groundwater pumping apparatus having the above configuration is embedded in the ground 1 in the same manner as in the above-described embodiment.
[0027]
Prior to the main pumping of the ground water in the ground 1 by the pumping means 4, the ground 1 around the lower portion of the casing pipe 3 is first subjected to ground modification so that the ground water can be easily passed.
[0028]
In performing ground reforming in the present embodiment, first, as shown in FIG. 5, the water supply valve 13 is opened with the on-off valve 6 closed and the air vent valve 5 opened, and the water supply pump 12 opens the casing tube. When pressurized water is pumped into 3 and the inside of the casing pipe 3 embedded in the ground 1 is filled with pressurized water as shown in FIG. 6, the air vent valve 5 is closed as shown in FIG. The pressurized water is pumped inside. In this way, a pressurized water pumping process is performed in which the pressurized water is forcibly pumped into the ground 1 around the casing tube 3 to split the ground 1 around the lower portion of the casing tube 3 with pressurized water.
[0029]
Next, as shown in FIG. 8, the operation of the water supply pump 12 is stopped, the water supply valve 13 is closed, the air vent valve 5 is closed, and the water pump 8 is operated in this state to pump the water in the casing pipe 3. The water filled in the casing pipe 3 is pumped by the pumping pump 8, whereby a vacuum space 15 is formed in the upper part of the casing pipe 3. Then, the clogging particles in the ground 1 are sucked into the casing pipe 3 together with the groundwater that has been pumped by the vacuum generated in the casing pipe 3 and is saturated in the ground 1. By continuing the operation of 6, the ground water and the clogged particles sucked into the casing pipe 3 are pumped by the pump 6, whereby the casing pipe 3 is formed with the vacuum space 15 formed in the upper part thereof. The groundwater and clogging substances will continue to be sucked inside. This is the cleaning pumping process.
[0030]
When the groundwater in the ground 1 that has become saturated by pumping pressurized water in this way is pumped, the pressurized water pumping step and the cleaning pumping step are alternately performed in the same manner. Here, in the second and subsequent pressurized water pumping steps, the air vent valve 5 is kept closed, the open / close valve 6 is closed, the water feed valve 13 is opened, and the water pump 12 pumps the pressurized water into the casing tube 3. Then, since the inside of the casing pipe 3 embedded in the ground 1 is filled with pressurized water, the pressurized water is forcedly fed into the ground 1 around the casing pipe 3 by continuously feeding the pressurized water into the casing pipe 3 by the water pump 12. Then, a pressurized water pumping process for forming a split water passage in the ground 1 around the lower portion of the casing tube 3 can be performed.
[0031]
Thus, clogging particles generated when a number of split water channels are formed around the lower portion of the casing tube 3 by pumping pressurized water to the ground 1 and when split water channels are formed by pumping pressurized water are vacuumed. By alternately forming suction and forced pumping by suction, the split water channel that becomes the “water channel” gradually grows so that the groundwater can flow smoothly and clogging particles are removed. This makes it easier for groundwater to flow more smoothly.
[0032]
When the ground reforming process for reforming the ground 1 around the lower portion of the casing tube 3 so that the ground water can smoothly flow is completed as described above, the water is then formed on the surrounding ground 1 by the pumping means 4. The main pumping step of pumping up groundwater by flowing it into the casing pipe 3 from the water-passing part 2 through the split split waterway is performed.
[0033]
This pumping process is performed as follows. That is, the pumping process for washing at the final stage of the ground reforming process can be continued to the main pumping process as shown in FIG. 9 and pumped by the pumping process by the same action as the pumping process for washing. It is something that can be done. In this main pumping process, since the split water passage has already been formed in the ground 1 around the lower part of the casing pipe 3 in the previous ground reforming process, the ground water passes smoothly through the formed split water passage. Therefore, the water collection into the casing tube 3 is effectively performed by the water head difference and the vacuum suction, and thus the water collection into the casing tube 3 is effectively performed. Therefore, pumping by the pumping pump 8 can be performed efficiently without loss. By the way, if the groundwater level temporarily decreases in the main pumping process and air flows into the casing tube 3 from the water passage 2 at the lower end of the casing tube 3, the degree of decompression of the space above the casing tube 3 decreases. However, the operation of the pump 8 may be continued as it is, but when the degree of decompression of the space above the casing pipe 3 is reduced, the suction force of the groundwater into the casing pipe 3 by vacuuming is reduced. Therefore, in such a case, the on-off valve 6 is closed, the air vent valve 5 is opened, the water supply valve 13 is opened, and the water supply pump 12 pumps pressurized water into the casing pipe 3 to evacuate the casing pipe 3. Filling with pressurized water, then stopping the operation of the water pump 12, closing the water valve 13 and closing the air vent valve 5, operating the pump 8 in this state to pump the water in the casing pipe 3, K Since the water filled in the ring pipe 3 is pumped up by the pumping pump 8, the vacuum space 15 can be formed in the upper part of the casing pipe 3, so that the pumping pump 8 can be operated continuously in this state. The groundwater can be pumped up while being vacuum sucked into the casing tube 3.
[0034]
In the present embodiment, the upper part of the casing tube 3 can be evacuated by a simple method without using a vacuum pump, and ground water and clogged particles can be sucked into the casing tube 3 by vacuum suction. .
[0035]
Moreover, in each said embodiment, in reforming the surrounding ground 1 so that the surrounding ground 1 of the lower part of the casing pipe | tube 3 may be split with pressurized water and the surrounding ground 1 may be reformed, In the above example, the ground 1 is improved by alternately sucking the ground water of the ground 1 saturated by the pumping of the pressurized water into the ground 1 and pumping it up by the pumping means 4. In order to reform the surrounding ground 1 so as to form a split water passage by splitting the surrounding ground 1 under the casing tube 3 with pressurized water, the pressurized water is continuously pumped to the surrounding ground 1 under the casing tube 3. It is also possible to form a split water passage that becomes a “water channel” in the ground 1 around the lower portion of the casing tube 3 only by doing so. For example, in the present embodiment, as shown in FIG. 1, the water supply valve 13 is opened with the on-off valve 6 and the air valve 10 closed, and pressurized water is pumped into the casing pipe 3 embedded in the ground 1 by the water supply pump 12. Then, pressurized water is pumped into the ground 1 from the water passing portion 2 at the lower end of the casing tube 3 through the water passage portion 23. By continuously executing only this pressurized water pumping process, the ground 1 around the lower part of the casing tube 3 is split by pressurized water, and the split water passage gradually grows to form a “water channel” through which groundwater flows smoothly. It forms a water channel.
[0036]
As described above, the ground reforming can be performed by simply forming a split water passage around the lower portion of the casing pipe 3 only by the pressurized water pumping process.
[0037]
After the ground modification around the lower part of the casing pipe 3 is thus performed, the main pumping is performed by the pumping means in the same manner as described above.
[0038]
In any of the above-described embodiments, the ground reforming process and the subsequent main pumping process are performed by the same groundwater pumping device, so that the ground reforming and pumping can be easily performed with a common device. Therefore, it is advantageous in terms of cost, and the construction period can be shortened.
[0039]
【The invention's effect】
  As described above, in the invention according to claim 1 of the present invention,The casing is provided with a water passing portion at a lower cylindrical portion at a lower end portion of the casing tube, and a vertically long strainer portion having a large number of water passage portions surrounding the lower cylindrical portion via gaps on the outer periphery of the lower cylindrical portion. The pipe is buried in the groundProvided at the lower end of the casing tubeThrough a large number of water passage parts of the strainer part, and gaps between the lower cylinder part and the strainer partPrior to pumping in the groundwater by pumping the groundwater from the water flow section, it was provided at the lower end of the casing tube.the abovePressurized water from the water flow sectionThrough the gap between the lower cylinder part and the strainer part, through a number of water passage parts of the strainer partA ground reforming process was carried out to reform the surrounding ground so that the ground surrounding the lower part of the casing pipe was split by pressurized water and the surrounding ground was reformed to form a split water passage. Later, the groundwater is drained through the split waterway formed in the surrounding ground by the pumping means.After passing through many water passage parts of the strainer part, the gap between the lower cylinder part and the strainer partSince the main pumping process of pumping water by flowing into the casing pipe from the water flow section is performed, the surrounding ground should be formed in advance so as to form a split water channel in the ground around the lower portion of the casing pipe before performing the main pumping. In the case of geology that can be reformed and can smoothly collect water from the water passing part into the inside of the casing pipe through the split water channel that has been pre-formed with groundwater for the main pumping, and the ground around the lower part of the casing pipe is difficult to pass water Even if the location of the groundwater in the ground and the location of the water flow part do not match, the water can be effectively collected in the casing tube and efficiently pumped by the pumping means.In particular, the pressurized water is pumped into the ground through the water passages, gaps, and many water passages of the strainer part provided in the lower cylindrical part at the bottom of the casing pipe to form a split water passage, Since the water is pumped in through the many water passages, gaps, and water passing parts of the strainer section, the ground improvement process and the subsequent main pumping process can be performed by the same underground pumping device. The equipment can easily improve the ground and pump water, which is advantageous in terms of cost. Furthermore, in modifying the surrounding ground so that the ground around the lower part of the casing pipe is split by pressurized water to form a split water passage, it is saturated by pumping pressurized water to the ground and pumping pressurized water to the ground. The ground is reformed by alternately sucking the groundwater from the ground that has been vacuumed and pumped by the pumping means, so that the ground around the lower part of the casing pipe is split in advance before performing the main pumping. When reforming the surrounding ground so as to form a water channel, by continuously pumping pressurized water to the surrounding ground at the bottom of the casing tube, the surrounding ground at the bottom of the casing tube can be easily split and vacuum suctioned Clogging particles generated by splitting due to water pumping are removed by suction, and this process is repeated to easily form a splitting water channel that removes the clogging particles and smoothes the water flow. It is those that can be reformed.
[0042]
  Also,Claim 2In the invention of the above,Claim 1In addition to the effects of the present invention, the water supply valve is opened with the open / close valve and the air valve closed, and the pressurized water is pumped into the casing pipe buried in the ground by the water pump, thereby supplying the pressurized water from the water passage portion into the ground. A pressurized water pumping process that splits the ground around the lower part of the casing pipe with pressurized water is carried out, and then the operation of the water pump is stopped and the water valve is closed and the open / close valve and air valve are opened. The pumping pump and the vacuum pump are operated to perform a pumping process for washing with the pumping pump while sucking the clogged particles in the ground together with the groundwater in the ground by vacuum suction into the casing pipe, and the pressurized water pumping process, Since the pumping process for washing is repeated alternately, pressurization is performed simply by opening / closing and operating / stopping the open / close valve and pump, air valve and vacuum pump, water pump and pump. The ground can be modified by alternately pumping the groundwater of the ground saturated by the pumping of the pressurized water to the ground and vacuuming the groundwater and pumping it by the pumping means. It is possible to easily improve the ground by forming a split water channel that removes particles and smoothes water flow.
[0043]
  Also,Claim 3In the invention of the above,Claim 1In addition to the effects of the present invention, with the on-off valve closed and the air vent valve opened, the water supply valve is opened and pressurized water is pumped into the casing pipe by the water pump to fill the casing pipe embedded in the ground with pressurized water. In this state, the air vent valve is closed, and then the pressurized water is pumped into the ground by a water pump to pump the pressurized water into the ground and the ground around the bottom of the casing pipe is split by the pressurized water. Next, stop the operation of the water supply pump, close the water supply valve, open the open / close valve with the air vent valve closed, operate the water pump to pump the water in the casing pipe, and A pumping pump that forms a vacuum space and sucks clogged particles in the ground into the casing pipe together with groundwater in the ground by suction generated by the vacuum generated in the casing pipe. Since the pumping process for washing to pump more water is carried out and the above pressurized water pumping process and the pumping process for washing are repeated alternately, the open / close valve and pump, the air vent valve, the water pump and the water valve are opened / closed, By simply operating the stop, pumping the pressurized water to the ground in a simple manner and alternately sucking the groundwater of the ground saturated by the pumping of the pressurized water into the vacuum and pumping it up by the pumping means alternately In particular, the upper part of the casing tube can be evacuated by a simple method without using a vacuum pump, and ground water and clogged particles can be sucked into the casing tube by vacuum suction. It is something that can be done.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing the order of a ground reforming process according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing the order of the ground reforming step.
FIG. 3 is an explanatory diagram of the main pumping process of the above.
FIG. 4 is an enlarged cross-sectional view of the lower part of an example of the casing pipe used in the above.
FIG. 5 is an explanatory diagram showing the order of the ground reforming process according to another embodiment of the present invention.
FIG. 6 is an explanatory diagram showing the order of the ground reforming step.
FIG. 7 is an explanatory diagram showing the order of the ground improvement process.
FIG. 8 is an explanatory diagram showing the order of the ground reforming step.
FIG. 9 is an explanatory diagram showing the order of the ground reforming step.
[Explanation of symbols]
1 ground
2 water passage
3 Casing tube
4 pumping means
5 Air vent valve
6 On-off valve
7 Pumping pipe
8 Pumping pump
9 Vacuum pump
10 Air valve
11 Vacuum tube
12 Water pump
13 Water supply valve
14 Water pipe

Claims

The casing is provided with a water passing portion at a lower cylindrical portion at a lower end portion of the casing tube, and a vertically long strainer portion having a large number of water passage portions surrounding the lower cylindrical portion via gaps on the outer periphery of the lower cylindrical portion. The pipe was buried in the ground, and the groundwater was introduced from the water passage part through the many water passage parts of the strainer part provided in the lower end part of the casing pipe, and the gaps between the lower cylinder part and the strainer part . groundwater prior to pumping by pumping means, the pressurized water from the water passage portion provided at the lower end of the casing tube via a number of water passing portion of the gap, the strainer portion between the lower tubular portion and the strainer portion A ground reforming process was carried out to reform the surrounding ground so that the ground surrounding the lower part of the casing pipe was split by pressurized water and the surrounding ground was reformed to form a split water passage. Later, for pumping means Numerous water passing portion of the strainer portion ground in through the formed split裂通waterways groundwater near Ri, present for pumping through the gap from the water passing portion to flow into the casing pipe between the lower tubular portion and the strainer portion A method for carrying out a pumping process, in which the ground around the lower part of the casing pipe is split with pressurized water and the surrounding ground is reformed so as to form a split water passage. A groundwater pumping method characterized in that the ground is reformed alternately by alternately sucking the groundwater of the ground saturated by pumping of pressurized water into the ground and pumping it up by a pumping means .

In reforming the surrounding ground so that the ground around the lower part of the casing pipe is split with pressurized water to form a split water passage, a pumping pump is provided at the lower end of the pumping pipe having an on-off valve to constitute pumping means. The pumping pipe is inserted into the casing pipe whose upper end is closed, the pumping pump is arranged at the lower part of the casing pipe, and the vacuum pipe having an air valve connected to the vacuum pump is connected to the upper end of the casing pipe and the casing. Connect a water supply pipe with a water supply valve connected to a water supply pump for supplying pressurized water into the pipe,
With the open / close valve and air valve closed, the water supply valve is opened and pressurized water is pumped into the casing pipe buried in the ground by the water pump, so that the pressurized water is pumped into the ground from the water passage. Implement a pressurized water pumping process to split the surrounding ground with pressurized water,
Next, stop the operation of the water pump, close the water supply valve, open the open / close valve and air valve, operate the pump and vacuum pump, and clog the ground together with the groundwater in the ground by vacuum suction. Implement a washing pumping process that pumps up particles with a pump while sucking particles into the casing tube,
The pressurized water pumping step and the cleaning pumping step are repeated alternately.
The groundwater pumping method according to claim 1.

In reforming the surrounding ground so that the ground around the lower part of the casing pipe is split with pressurized water to form a split water passage, a pumping pump is provided at the lower end of the pumping pipe having an on-off valve to constitute pumping means. The pumping pipe is inserted into a casing pipe whose upper end is closed, a pumping pump is arranged at the lower part of the casing pipe, an air venting part having an air venting valve is connected to the upper end part of the casing pipe, and pressurized water is introduced into the casing pipe. Connect the water pipe with the water valve connected to the water pump for supplying
With the open / close valve closed, the air release valve opened, the water supply valve opened, the water pump pumped pressurized water into the casing pipe, and the casing pipe embedded in the ground was filled with pressurized water, and the air release valve was closed, Subsequently, the pressurized water is pumped into the casing pipe by a water pump to pressurize the pressurized water into the ground from the water passage portion, and the pressurized water pumping process is performed to split the ground around the lower portion of the casing pipe with the pressurized water.
Next, the operation of the water pump is stopped, the water valve is closed and the air vent valve is closed, the open / close valve is opened, the pump is operated to pump the water in the casing pipe, and a vacuum space is formed above the casing pipe. A washing pumping process for pumping up water by a pump while sucking clogged particles in the ground into the casing pipe together with groundwater in the ground by suction generated by the vacuum generated in the casing pipe,
The groundwater pumping method according to claim 1, wherein the pressurized water pumping step and the cleaning pumping step are repeated alternately.