JP2004144392A

JP2004144392A - Chimney deconstructing method

Info

Publication number: JP2004144392A
Application number: JP2002309919A
Authority: JP
Inventors: Eiichi Kawazoe; 川添　栄一
Original assignee: NARATA KK; Taisei Corp; Taiyo Kogyo Co Ltd
Current assignee: NARATA KK; Taisei Corp; Taiyo Kogyo Co Ltd
Priority date: 2002-10-24
Filing date: 2002-10-24
Publication date: 2004-05-20
Anticipated expiration: 2022-10-24
Also published as: JP3853284B2

Abstract

<P>PROBLEM TO BE SOLVED: To improve the efficiency in deconstructing work by preventing the scattering of powder dust and harmful substances from an upper part of a chimney in deconstructing the chimney mounted on an incinerator or a combustion furnace. <P>SOLUTION: The circumference of a scaffold 10 built up to a height near a top, around the chimney T is surrounded by a first sheet 30, a top frame 20 is placed on an upper part of the uppermost scaffold, the circumference of the chimney T is shut off from the outside air by surrounding the circumference of the top counter 20 by a second sheet 40, and further the circumference of a lower part of the first sheet 30 surrounding the circumference of the scaffold 10 is surrounded by a third sheet 50 to form a working space shut out from the outside air. The chimney deconstructing work is performed through processes of cleaning the inside of the chimney T, removing a firebrick wall F inside, and removing an outer wall A in a state that the working space is depressurized to be lower than an atmospheric pressure, whereby scattering of the powder dust and residual harmful substance generated during the deconstructing work to the external can be prevented, and a series of works can be efficiently performed. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、焼却炉や燃焼炉に付設された煙突を撤去するために解体する際の解体工法に関する。
【０００２】
【従来の技術】
既設の建築物を撤去あるいは改造するために解体する場合、その周りが開放されたままの状態で解体工事を行うと、工事中に発生する大量の粉塵が飛散して周囲の環境に悪影響を与えたり、ガラス破片などの破砕された建築部材が周辺に落下して人的、物的被害を生じたりする。そこで、解体する建築物の周りを足場とシートで囲んで粉塵の飛散や部材の落下を防ぐとともに、解体中の建築物や作業空間に散水して粉塵の飛散を抑えながら解体工事を行うことが一般的に行われている。
【０００３】
焼却炉や燃焼炉に付設された煙突を解体する場合も、煙突の周りを囲んで粉塵の飛散や部材の落下を防ぐ工法が行われている。たとえば特許文献１に、煙突に近接して作業用足場を仮設し、次いで、この作業用足場の周囲に仮囲いを地面から仮設することが記載されている。この仮囲いは、煙突の短尺切断加工工程中における粉塵の発生による周囲環境や作業者への汚染を防止するために配置されるものであり、作業用足場および煙突の高さよりも高くされていることが、汚染をより確実に防止する点から好ましいとされている。
【０００４】
【特許文献１】
特開２００２−１２１９０６号公報（段落番号００３０）
【特許文献２】
特開２００２−４７８１２号公報（段落番号０００７−００１１）
【０００５】
【発明が解決しようとする課題】
従来の建築物の解体工法の場合、建築物の周りは足場とシートで囲まれているが、建築物の上方は開放状態であるため、風に乗って上昇しやすい微細な粉塵などの飛散を止めることはできない。また、粉塵の飛散を抑えるために解体工事中は頻繁に散水する必要があるため大量の水が必要であり、撒かれた水が隣接地や道路などに流出して悪影響を与えることがないように排水処理対策を講じる必要がある。さらに、アスベストなどの有害資材が使用された古い建築物や、ごみ焼却炉などのように焼却灰に含まれていた有害物質が残留している可能性のある建築物などを解体する場合、従来の解体工法では、有害物質が飛散して環境汚染を引き起こすおそれがある。
【０００６】
このような問題に対して本出願人は、たとえばごみ焼却設備のような建築物の周囲をシートで包囲して外気と遮断した工事用空間を形成し、この工事用空間内の気圧を大気圧より低く保持した状態で建築物を解体する工法を開発し、特許文献２として開示した。この工法によれば、外気と遮断された工事用空間は常に負圧に保たれ、工事用空間内の空気が外部に拡散しないようにして解体工事を行うことができる。これにより、工事中に発生した粉塵や残留有害物質などが工事用空間から外へ飛散することがなく、解体工事中の散水も不要となる、という効果を奏する。
【０００７】
ところが、ごみ焼却設備に付設された煙突の解体工法は、特許文献１に記載のような、煙突の周りを足場とシートで囲む従来の工法がそのまま現在でも実施されており、開放状態である煙突上方からの粉塵の飛散を止めることができない、という問題が残されたままである。
【０００８】
また、特許文献１に記載の工法では、ワイヤソーによる煙突の短尺切断作業、およびこの短尺切断加工により切断された部分を作業機械により小割する作業が必要であり、これらの作業に長時間を要し、解体作業全体の能率が低いという問題がある。
【０００９】
本発明が解決すべき課題は、焼却炉や燃焼炉に付設された煙突を解体するに際して、粉塵や有害物質が煙突の上方から飛散するのを防止し、かつ解体工事の能率を向上させることにある。
【００１０】
【課題を解決するための手段】
本発明の煙突解体工法は、被解体物である煙突の周囲に同煙突の頂部に近い高さまで足場を組み上げ、この組み上げた足場の周囲を第１のシートで包囲し、最上段の前記足場の上部に煙突の頂部より高い架台を設置し、この架台の周囲を第２のシートで包囲して煙突の周囲を外気と遮断し、さらに、足場の周囲を包囲した前記第１のシートの下部の周囲を第３のシートで包囲して外気と遮断した作業用空間を形成し、この作業用空間を大気圧より低くした状態で、
（１）煙突内部を洗浄する工程
（２）煙突内部の耐火煉瓦を撤去する工程
（３）煙突外壁を撤去する工程
の各工程を含む作業工程を経て煙突を解体することを特徴とする。
【００１１】
煙突の上方も含めて煙突の周囲を外気と遮断することにより、解体作業中に発生する粉塵が煙突の上方から大気中に飛散することが防止される。さらに、外気と遮断した作業用空間を常に負圧に保ち、作業用空間内の空気が外部に拡散しないようにして解体作業を行うことができる。作業用空間は、破砕して煙突底部に落下させた耐火煉瓦や外壁の破砕物を煙突内から掻き出して一時的に集積し、その後外部に搬出する作業を行う空間であり、この作業用空間を負圧に保持することにより、解体作業中に発生した粉塵や残留有害物質などが作業用空間から外部へ飛散することが防止される。
【００１２】
作業用空間内の気圧を大気圧より低く保持するためには、エアポンプにより作業用空間内の空気を吸引する。エアポンプによる吸引は連続的でも間欠的でもよく、これにより作業用空間内を負圧にすることができる。作業用空間内を負圧に保持することにより、シートによる外気との遮断に不完全な部分があっても、作業用空間内の空気が外部に洩れることはなく、逆に外気が導入されることになり、作業用空間内の空気の入れ替えが行われることになる。
【００１３】
作業用空間には出入り用通路を設けることが望ましい。この通路の前部と後部に開閉扉を設けて通路を外気と遮断することにより、作業用空間内への作業員の出入り、工事用車両や機械の出し入れ、解体後の廃材の搬出などは、作業用空間内の気圧の増加を招くことなく、この通路を経由して行うことができる。さらに、作業用空間内から吸引した空気をフィルタで濾過するなどして吸引空気中の浮遊物を集塵して回収することにより、解体作業中に発生する粉塵や有害物質などを回収除去できるようになるため、エアポンプからの排気による環境汚染を防止することができる。
【００１４】
煙突の周囲を包囲する第１、第２のシートおよび作業用空間を形成するための第３のシートとしては、気密性、強度、耐候性、耐久性などに優れ、太陽光線、気温変化、風雨や氷雪などによって容易に破壊されることのない帆木綿や合成樹脂シートを用いる。なお、シートとして紫外線や赤外線などを遮蔽する機能を有するものを用いれば、シートで包囲された空間内への紫外線侵入や温度上昇を抑制することができるので、防護服や防塵マスクを身に着けた作業者の作業環境を向上させることができる。
【００１５】
煙突の頂部に近い高さまで組み上げる足場は、１個の高さが１〜２ｍ程度の組立用足場を煙突高さ方向に多数段積み上げた構造とするのが望ましい。このような構造とすることにより、煙突上部の外壁を破砕撤去して煙突高さが低くなるにしたがって、上部の組立用足場を順次取り外して頂部の架台を順次低い位置に降ろしていくことができる。
【００１６】
頂部の架台は、煙突上部の包囲用の第３のシートを保持する機能のほかに、この架台の上部桁から煙突内に、煙突内部洗浄用の洗浄機や外壁破砕用の破砕機を吊り下げる機能を持たせる。このため架台は、強度の高い鋼製フレーム構造とし、とくに上部桁には十分な強度を持たせるようにする。
【００１７】
煙突内部を洗浄する工程は、頂部の架台から吊り下げた高圧水洗浄機を煙突内部に挿通させ、外部から供給される高圧水を煙突内部の耐火煉瓦壁内面に吹き付けて燃焼付着灰を剥離除去する工程である。煙突の周囲はシートにより包囲されているので、煙突内部の燃焼付着灰が舞い上がったとしても周囲環境に放出されることはほとんどない。洗浄により剥離除去された燃焼付着灰を含む洗浄水は、配管を通じて排水処理装置に送り、燃焼灰とダイオキシンなどの有害物質を除去し、処理後の水は洗浄用高圧水に再利用する。ここで使用する高圧水洗浄機としては、公知の高圧水洗浄機を使用することができる。
【００１８】
煙突内部の耐火煉瓦を撤去する工程は、頂部の架台または煙突上端に設けた梁から吊り下げた作業用ゴンドラを煙突内部に挿通させ、このゴンドラに乗った作業者がハンドブレーカーなどの破砕器具を用いて耐火煉瓦を破砕し剥離除去する工程である。この工程は、煙突内部を洗浄する工程の後に行われるので、耐火煉瓦に付着した燃焼灰は除去された後であり、耐火煉瓦の破砕時に燃焼灰が舞い上がることはない。剥離除去されて煙突底部に堆積した耐火煉瓦屑は煙突底部の開口から煙突外に掻き出され、作業空間から外部に搬出される。
【００１９】
前記工程により煙突内部の耐火煉瓦を撤去した後に、耐火煉瓦除去後の外壁内面を洗浄することが好ましい。この洗浄工程は、作業用ゴンドラを残った外壁内に挿通させ、この作業用ゴンドラに乗った作業者が外部から供給される高圧水を外壁の内面に吹き付けて、煉瓦粉などの付着物を洗い流す工程である。煉瓦粉などを含む洗浄水は、前記と同様に排水処理装置に送られ処理される。なお、耐火煉瓦除去後の外壁内面に残る煉瓦粉などが少ない場合は、この洗浄工程は省略してもよい。
【００２０】
煙突外壁を撤去する工程は、組立用足場の上部に配置された作業者が外部に設置された油圧機本体を遠隔操作して、頂部の架台から吊り下げた油圧破砕機を操作し、外壁を油圧破砕機により順次破砕する工程である。外壁は通常鉄筋コンクリート製であり、破砕したコンクリート片は煙突底部に落下させ、鉄筋は作業者がカッタを用いて切断し、同様に煙突底部に落下させる。
【００２１】
多数段に積み上げた組立用足場の１個ないし２個の足場の高さに相当する高さ分の外壁の撤去が終わると、頂部の架台をクレーンで吊り上げた状態で１段または２段の組立用足場を取り外し、最上段となる組立用足場の上部に再び頂部の架台を載置する。以下、油圧機器による外壁の破砕、組立用足場の取り外し、頂部架台降ろしの各作業を順次繰り返して外壁の撤去作業を終了する。
【００２２】
外壁の撤去作業の終了後、作業空間内に一次集積した煉瓦屑、コンクリート片、鉄筋片などを外部に搬出し、その後、頂部架台、組立足場、シートなどを片付けて煙突解体作業を終了する。
【００２３】
【発明の実施の形態】
図１は本発明の煙突解体工法の実施形態における煙突周囲の遮蔽状況を示す平面図、図２は同じく煙突周囲の遮蔽状況を示す斜視図、図３〜図８は各作業工程の説明図である。
【００２４】
本実施形態は、稼働を休止したごみ焼却設備の煙突の解体工事の例であり、図１に示すごみ焼却設備（図では建家の一部のみ示す）Ｓの煙突Ｔを解体撤去する工事である。工事の主要工程は次の通りである。
（１）煙突Ｔの周囲に足場１０と頂部架台２０を構築し、シート３０と４０で包囲する工程
（２）煙突Ｔをシート３０で包囲した外側に、支柱５１とワイヤ５２とシート５０により外気と遮断した作業用空間Ｗを形成する工程
（３）煙突Ｔの内部に高圧水洗浄機６０を挿通して、耐火煉瓦壁Ｆの内面の燃焼付着物を高圧水により剥離除去する工程
（４）高圧水洗浄による排水を清浄化する工程
（５）煙突Ｔの内部に作業者Ｍが乗った作業用ゴンドラ７０を挿通して、煙突Ｔの内部の耐火煉瓦壁Ｆをハンドブレーカーにより破砕して除去する工程
（６）耐火煉瓦の破砕片ｆを外部に搬出する工程
（７）残った外壁Ａの内部に作業者Ｍが乗った作業用ゴンドラ７０を挿通して、外壁Ａの内面を高圧水により洗浄する工程
（８）高圧水洗浄による排水を清浄化する工程
（９）油圧破砕機８０により残った外壁Ａを破砕する工程
（１０）外壁Ａの破砕片ａを外部に搬出する工程
（１１）足場１０、頂部架台２０、支柱５１、ワイヤ５２、シート３０，４０，５０を撤去する工程
【００２５】
以下、上記の各工程について順に説明する。
図１に示すように、煙突Ｔはごみ焼却設備Ｓの建家に隣接して設けられている。本実施形態では、ごみ焼却設備Ｓの解体撤去も全体工事のなかに含まれているので、建家の周囲もシートで包囲されているが、図１では図示を省略している。ごみ焼却設備Ｓの解体撤去工事と煙突Ｔの解体撤去工事は同時に並行して実施してもよく、またいずれか一方の工事を先に完了してから他方の工事を実施するようにしてもよい。
【００２６】
煙突解体工事にあたっては、まず図２に示すように、煙突Ｔの周囲に足場１０と頂部架台２０を構築し、シート３０と４０で包囲する。足場１０は、地面から煙突Ｔの頂部に近い高さまで組み上げる。この足場１０は、１個の高さが１〜２ｍ程度の鋼製フレーム構造の組立用足場１１，１２，・・・１ｎ（図３参照）を煙突Ｔの高さ方向にｎ段積み上げた構造である。このような構造とすることにより、図６に示すように煙突Ｔの外壁Ａの上部を破砕撤去して煙突高さが低くなるにしたがって、図７に示すように上部の組立用足場を順次取り外して頂部架台２０を順次低い位置に降ろしていくことができる。この足場１０の周囲をテントなどに使用される合成樹脂製のシート３０で包囲する。
【００２７】
頂部架台２０は、図８に示すような一体的な鋼製フレーム構造物であり、煙突上部の包囲用のシート４０を保持する機能のほかに、この頂部架台２０の上部桁２１から煙突Ｔの内部に、煙突内部洗浄用の高圧水洗浄機６０や外壁破砕用の油圧破砕機８０を吊り下げる機能を持たせる。この頂部架台２０の周囲を合成樹脂製のシート４０で包囲する。
【００２８】
ついで、図１に示す作業用空間Ｗを形成する。作業用空間Ｗは、足場１０の周囲を包囲したシート３０の外側に、工事用車両が出入りして煙突内部からの解体屑の掻き出しや外部への搬出作業が可能な広さと高さを有して、外気と遮断された領域である。本実施形態では、図１および図３に示すように、鋼製の支柱５１とワイヤ５２と合成樹脂製のシート５０により作業用空間Ｗを形成している。
【００２９】
さらに、作業用空間Ｗを解体作業場ｗ_１と通路ｗ_２に区分し、通路ｗ_２の前部と後部に開閉扉５３，５４を設けて、作業用空間Ｗ内への作業員の出入り、工事用車両や機械の出し入れ、解体後の廃材の搬出などを、作業用空間Ｗ内の気圧の増加を招くことなく行うことができるようにしている。また、通路ｗ_２内に車両や機械の水洗装置や作業者のエアーシャワー装置（いずれも図示せず）などを設置して、外部の汚染を防止するようにしている。
【００３０】
作業用空間Ｗ内の気圧を大気圧より低く保持するために、シート５０の一部に吸引口５５を設け、エアポンプ（図示せず）により作業用空間Ｗ内の空気を吸引する。エアポンプは、解体作業を行っているときは連続的に運転し、作業休止中は間欠的に運転することで、作業用空間Ｗ内を負圧に保つことができる。作業用空間Ｗ内の空気をエアポンプで吸引することによって、シート５０の継ぎ目の僅かな隙間や開閉扉ｗ_１，ｗ_２の僅かな隙間を通じて外気が作業用空間Ｗ内へ導入されて空気の入れ替えが行われるため、作業用空間Ｗ内は作業に適した状態に維持することができる。
【００３１】
以上の準備作業が終了した後、煙突内部の洗浄作業と解体作業に入る。
最初の洗浄作業は、煙突Ｔの内部に高圧水洗浄機６０を挿通して、耐火煉瓦壁Ｆの内面の燃焼付着物を高圧水により剥離除去する作業である。図３に示すように、頂部架台２０の上部桁２１から煙突Ｔの内部に、煙突内部洗浄用の高圧水洗浄機６０をウインチ（図示せず）を介して吊り下げる。高圧水洗浄機６０は、ノズル先端から高圧水を吹き付けて洗浄する公知の洗浄機であり、詳細な機能、構造の説明は省略する。この洗浄作業では、高圧水ホース６１を通じて外部から供給される高圧水を煙突Ｔ内部の耐火煉瓦壁Ｆ内面に吹き付けて洗浄する。
【００３２】
洗浄により剥離除去された燃焼付着灰を含む洗浄水は、配管（図示せず）を通じて排水処理装置（図示せず）に送り、燃焼灰とダイオキシンなどの有害物質を除去し、処理後の水は洗浄用高圧水に再利用する。排水処理装置は、重金属補修処理槽と凝集沈殿槽と活性炭処理槽を備え、関係法令で定める排出基準を満たした洗浄水とする。処理後の洗浄水は、再び高圧洗浄機６０に送る高圧水として再利用する。
【００３３】
第１の洗浄作業が終わったら高圧水洗浄機６０を撤去し、ついで図４に示すように、煙突Ｔの内部に作業者Ｍが乗った作業用ゴンドラ７０を挿通して、煙突Ｔの内部の耐火煉瓦壁Ｆをハンドブレーカーにより破砕して除去する。作業用ゴンドラ７０は、煙突上端に掛け渡した梁７１からウインチ（図示せず）を介して吊り下げ、作業者Ｍが乗り込んでハンドブレーカーにより耐火煉瓦壁Ｆを破砕する。煙突底部に落下した耐火煉瓦の破砕片ｆは、煙突底部の開口Ｔｏ（図２参照）からバックホウＢにより掻き出され、外部に搬出される。
【００３４】
つぎに二回目の洗浄作業を行う。図５に示すように、作業用ゴンドラ７０を煙突内部に挿通させ、この作業用ゴンドラ７０に乗った作業者が外部から供給される高圧水を煙突外壁Ａの内面に吹き付けて、耐火煉瓦壁Ｆを除去した後に外壁Ａに付着した煉瓦粉を洗い流す。煉瓦粉などを含む洗浄水は、第１の洗浄作業の場合と同様に排水処理装置に送られ処理される。
【００３５】
二回目の洗浄作業が終わったら作業用ゴンドラ７０を撤去し、ついで図６に示すように、油圧破砕機８０により残った外壁Ａを破砕する。この作業は、最上段の足場上部に配置された作業者Ｍが外部に設置された油圧機本体（図示せず）を遠隔操作して、頂部架台２０の上部桁２１に取り付けた梁２２からチェインブロック（図示せず）を介して吊り下げた油圧破砕機８０を操作し、外壁Ａを油圧破砕機８０により順次破砕する作業である。梁２２は、図示しない桁に沿って図６の紙面方向に移動可能であり、チェインブロックを二方向に移動させることで外壁Ａを順次破砕することができる。油圧破砕機８０は、公知の破砕機であり、作業者Ｍがリモートコントローラにより油圧機本体を遠隔操作する。外壁Ａは鉄筋コンクリート製であり、破砕した破砕片ａは煙突底部に落下させ、鉄筋は作業者Ｍがカッタを用いて切断し、同様に煙突底部に落下させる。
【００３６】
多数段に積み上げた足場１０の２個の組立用足場１１，１２の高さに相当する高さ分の外壁Ａの撤去が終わると、図７に示すように、頂部架台２０をクレーンＣｒ（図２参照）で吊り上げた状態で２段の組立用足場１１，１２を取り外し、最上段となる組立用足場１３の上部に再び頂部架台２０を載置する。以下、油圧機器８０による外壁の破砕、組立用足場の取り外し、頂部架台降ろしの各作業を順次繰り返して（図８参照）、全部の外壁Ａを破砕撤去する。
【００３７】
外壁Ａの破砕撤去作業の終了後、作業空間内に一次集積した耐火煉瓦壁Ｆの破砕片ｆ、外壁Ａの破砕片ａ、鉄筋片などを外部に搬出し、その後、作業用空間Ｗを形成していた支柱５１、ワイヤ５２、シート５０、地上に降ろされた足場１０、頂部架台２０、シート３０，４０などを片付けて煙突解体作業を終了する。
【００３８】
【発明の効果】
（１）煙突の上方も含めて煙突の周囲を外気と遮断し、外気と遮断した作業用空間を形成し、この作業用空間を大気圧より低くした状態で、煙突の解体作業を行うことにより、解体作業中に発生した粉塵や残留有害物質などが外部へ飛散することが防止される。
（２）煙突内部を高圧水洗浄機により洗浄し、煙突内部の耐火煉瓦を破砕して除去し、残った外壁を破砕除去する作業工程とすることにより、一連の作業を能率的に行うことができる。
【図面の簡単な説明】
【図１】本発明の煙突解体工法の実施形態における煙突周囲の遮蔽状況を示す平面図である。
【図２】煙突周囲の遮蔽状況を示す斜視図である。
【図３】煙突内部の洗浄工程の説明図である。
【図４】耐火煉瓦壁の破砕除去工程の説明図である。
【図５】外壁内面の洗浄工程の説明図である。
【図６】外壁の破砕除去工程の説明図である。
【図７】外壁の破砕除去工程の説明図である
【図８】外壁の破砕除去工程の説明図である
【符号の説明】
１０　足場
１１〜１４，・・・１ｎ　組立用足場
２０　頂部架台
２１　上部桁
２２　梁
３０，４０，５０　シート
５１　支柱
５２　ワイヤ
５３，５４　開閉扉
５５　吸引口
６０　高圧水洗浄機
６１　高圧水ホース
７０　作業用ゴンドラ
７１　梁
８０　油圧破砕機
Ｓ　ごみ焼却設備
Ｔ　煙突
Ｔｏ開口
Ｗ　作業用空間
ｗ_１　解体作業場
ｗ_２　通路
Ｆ　耐火煉瓦壁
ｆ　耐火煉瓦の破砕片
Ａ　外壁
ａ　外壁の破砕片
Ｂ　バックホウ
Ｃｒ　クレーン
Ｍ　作業者[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dismantling method for dismantling a chimney attached to an incinerator or a combustion furnace to remove the chimney.
[0002]
[Prior art]
When demolishing an existing building to remove or modify it, if the demolition work is performed with the surrounding area left open, a large amount of dust generated during the construction will scatter and adversely affect the surrounding environment. Also, crushed building members such as glass shards fall to the periphery and cause human and property damage. Therefore, it is necessary to surround the building to be demolished with scaffolds and sheets to prevent dust scattering and falling members, and to dismantle construction while spraying water on the building and work space being demolished to suppress scattering of dust. Generally done.
[0003]
In the case of dismantling a chimney attached to an incinerator or a combustion furnace, a method of preventing dust from scattering and falling of members around the chimney has been adopted. For example, Patent Literature 1 describes that a work scaffold is temporarily provided near a chimney, and a temporary enclosure is temporarily provided around the work scaffold from the ground. This temporary enclosure is arranged to prevent contamination of the surrounding environment and workers due to generation of dust during the short cutting process of the chimney, and is higher than the height of the working scaffold and the chimney. Is preferred from the viewpoint of more reliably preventing contamination.
[0004]
[Patent Document 1]
JP 2002-121906 A (paragraph number 0030)
[Patent Document 2]
JP-A-2002-47812 (paragraph number 0007-0011)
[0005]
[Problems to be solved by the invention]
In the case of the conventional building demolition method, the building is surrounded by scaffolds and sheets, but the upper part of the building is open, so that fine dust and other dust that easily rises on the wind is scattered. I can't stop it. In addition, a large amount of water is required during dismantling work to reduce the scattering of dust, so a large amount of water is required. It is necessary to take measures for wastewater treatment. Furthermore, when dismantling old buildings that use harmful materials such as asbestos, or buildings that may contain harmful substances contained in incineration ash, such as garbage incinerators, In the dismantling method, harmful substances may scatter and cause environmental pollution.
[0006]
In response to such a problem, the present applicant forms a construction space that is surrounded by sheets around a building such as a garbage incinerator, and blocks the outside air. A construction method for dismantling a building while keeping it lower is developed and disclosed as Patent Document 2. According to this method, the construction space that is cut off from the outside air is always kept at a negative pressure, and the dismantling work can be performed while preventing the air in the construction space from diffusing to the outside. As a result, dust and residual harmful substances generated during the construction do not scatter out of the construction space, and watering during the dismantling construction is not required.
[0007]
However, as a method of dismantling a chimney attached to a refuse incinerator, a conventional method of surrounding a chimney with a scaffold and a sheet, as described in Patent Document 1, is still being implemented as it is, and the chimney in an open state. The problem remains that the scattering of dust from above cannot be stopped.
[0008]
Further, the method described in Patent Document 1 requires a short cutting operation of a chimney using a wire saw and a work of dividing a portion cut by the short cutting process with a working machine, and these operations require a long time. However, there is a problem that the efficiency of the entire dismantling work is low.
[0009]
The problem to be solved by the present invention is to prevent dust and harmful substances from being scattered from above the chimney when dismantling a chimney attached to an incinerator or a combustion furnace, and to improve the efficiency of dismantling work. is there.
[0010]
[Means for Solving the Problems]
In the chimney dismantling method of the present invention, a scaffold is assembled around a chimney which is an object to be dismantled to a height close to the top of the chimney, the periphery of the assembled scaffold is surrounded by a first sheet, and A pedestal higher than the top of the chimney is installed at the upper part, the periphery of the pedestal is surrounded by a second sheet, the surroundings of the chimney are shut off from the outside air, and the lower part of the first sheet surrounding the periphery of the scaffold is further enclosed. A work space surrounded by a third sheet and surrounded by the outside air is formed, and in a state where the work space is lower than the atmospheric pressure,
(1) a step of cleaning the inside of the chimney; (2) a step of removing a refractory brick inside the chimney; and (3) a step of removing the chimney outer wall.
[0011]
By shielding the surroundings of the chimney including the area above the chimney from the outside air, dust generated during the dismantling operation is prevented from being scattered from above the chimney into the atmosphere. Further, the work space, which is isolated from the outside air, is always kept at a negative pressure, and the disassembly work can be performed while preventing the air in the work space from diffusing to the outside. The work space is a space where the refractory bricks and crushed material on the outer wall that have been crushed and dropped to the bottom of the chimney are scraped out of the chimney, temporarily accumulated, and then carried out to the outside. By maintaining the negative pressure, dust and residual harmful substances generated during the dismantling operation are prevented from scattering from the working space to the outside.
[0012]
In order to maintain the pressure in the working space lower than the atmospheric pressure, air in the working space is sucked by an air pump. The suction by the air pump may be continuous or intermittent, so that a negative pressure can be created in the working space. By maintaining the inside of the working space at a negative pressure, even if there is an incomplete portion of the sheet blocking the outside air, the air in the working space does not leak to the outside, and conversely, the outside air is introduced. This means that the air in the working space is replaced.
[0013]
It is desirable to provide an access passage in the working space. By opening and closing doors at the front and rear of this passage to block the passage from outside air, workers can enter and exit the work space, take in and out construction vehicles and machines, and carry out waste materials after dismantling, etc. This can be performed via this passage without increasing the pressure in the working space. In addition, dust and harmful substances generated during dismantling work can be collected and removed by collecting and collecting suspended matter in the sucked air by filtering the air sucked from the working space with a filter or the like. Therefore, environmental pollution due to exhaust air from the air pump can be prevented.
[0014]
The first and second sheets surrounding the chimney and the third sheet for forming the work space are excellent in airtightness, strength, weather resistance, durability, etc., and are excellent in sunlight, temperature change, wind and rain. Use a sail cotton or synthetic resin sheet that is not easily destroyed by ice or snow. If a sheet that has a function of blocking ultraviolet rays or infrared rays is used, it is possible to suppress the penetration of ultraviolet rays into the space surrounded by the sheet and the rise in temperature, so wear protective clothing and a dust mask. The working environment of the worker can be improved.
[0015]
It is desirable that the scaffold assembled to a height close to the top of the chimney has a structure in which a plurality of assembly scaffolds each having a height of about 1 to 2 m are stacked in the stack height direction. By adopting such a structure, as the chimney height is lowered by crushing and removing the outer wall of the chimney upper part, the upper assembling scaffold can be sequentially removed and the top pedestal can be lowered sequentially to a lower position. .
[0016]
In addition to the function of holding the third sheet for surrounding the upper part of the chimney, the top mount suspends a washing machine for cleaning the inside of the chimney and a crusher for crushing the outer wall from the upper girder of the mount into the chimney. Have a function. For this reason, the gantry has a high-strength steel frame structure, and the upper spar is given sufficient strength.
[0017]
In the process of cleaning the inside of the chimney, a high-pressure water washer suspended from the top of the stack is inserted through the inside of the chimney, and high-pressure water supplied from the outside is sprayed on the inside of the refractory brick wall inside the chimney to remove and remove combustion ash. This is the step of doing. Since the chimney is surrounded by the sheet, even if the combustion ash inside the chimney rises, it is hardly released to the surrounding environment. The cleaning water containing combustion ash separated and removed by the cleaning is sent to a wastewater treatment apparatus through a pipe to remove harmful substances such as combustion ash and dioxin, and the treated water is reused as high-pressure cleaning water. As the high-pressure water washer used here, a known high-pressure water washer can be used.
[0018]
In the process of removing the refractory brick inside the chimney, a work gondola suspended from the top frame or the beam provided at the top of the chimney is inserted through the chimney, and the worker riding this gondola removes crushing equipment such as a hand breaker. In this step, the refractory brick is crushed and peeled off. Since this step is performed after the step of cleaning the inside of the chimney, the combustion ash adhering to the refractory brick is removed, and the combustion ash does not fly when the refractory brick is crushed. The refractory brick debris that has been separated and deposited on the bottom of the chimney is scraped out of the chimney through an opening in the bottom of the chimney, and is carried out of the working space to the outside.
[0019]
After removing the refractory brick inside the chimney in the above step, it is preferable to wash the inner surface of the outer wall after removing the refractory brick. In this cleaning step, the work gondola is inserted into the remaining outer wall, and a worker riding the work gondola sprays high-pressure water supplied from the outside onto the inner surface of the outer wall to wash off deposits such as brick powder. It is a process. The washing water containing the brick powder and the like is sent to the wastewater treatment device and treated in the same manner as described above. In addition, if there is little brick powder or the like remaining on the inner surface of the outer wall after removing the refractory bricks, the washing step may be omitted.
[0020]
In the process of removing the chimney outer wall, the operator arranged above the scaffold for assembly remotely controls the hydraulic machine body installed outside, operates the hydraulic crusher suspended from the top frame, and removes the outer wall. This is a step of sequentially crushing with a hydraulic crusher. The outer wall is usually made of reinforced concrete, and the crushed concrete pieces are dropped to the bottom of the chimney, and the reinforcing bar is cut by an operator using a cutter, and similarly dropped to the bottom of the chimney.
[0021]
When removal of the outer wall corresponding to the height of one or two scaffolds of the assembling scaffolds stacked in multiple stages is completed, one- or two-stage assembling is performed in a state in which the top frame is lifted by a crane. The scaffold is removed, and the top pedestal is placed again on the top of the uppermost scaffold for assembly. Hereinafter, the operations of crushing the outer wall by the hydraulic device, removing the scaffold for assembly, and lowering the top gantry are sequentially repeated to complete the removing operation of the outer wall.
[0022]
After the removal of the outer wall is completed, the brick waste, concrete pieces, rebar pieces, and the like, which have been primarily accumulated in the work space, are carried out, and then the top stand, the assembled scaffold, the sheets, and the like are cleared, and the chimney dismantling work is completed.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a plan view showing the state of shielding around the chimney in the embodiment of the chimney dismantling method of the present invention, FIG. 2 is a perspective view showing the state of shielding around the chimney, and FIGS. is there.
[0024]
This embodiment is an example of dismantling construction of a chimney of a refuse incineration plant whose operation has been suspended, and is a construction for dismantling and removing a chimney T of a refuse incineration plant (only a part of the building is shown in the figure) S shown in FIG. is there. The main construction process is as follows.
(1) A step of constructing the scaffold 10 and the top gantry 20 around the chimney T and surrounding it with the sheets 30 and 40. (3) Step of inserting high-pressure water washer 60 into chimney T to separate and remove combustion deposits on the inner surface of refractory brick wall F with high-pressure water (4) Step (5): A work gondola 70 on which a worker M rides is inserted into the chimney T, and the refractory brick wall F inside the chimney T is crushed and removed by a hand breaker. (6) Step of carrying out the crushed pieces f of the refractory brick to the outside (7) Insert the work gondola 70 on which the worker M rides into the inside of the remaining outer wall A, and pressurize the inner surface of the outer wall A with high-pressure water. Cleaning process (8) Draining by high pressure water cleaning (9) Step of crushing the remaining outer wall A by the hydraulic crusher 80 (10) Step of carrying out the crushed pieces a of the outer wall A to the outside (11) Scaffold 10, top mount 20, support column 51, wire 52, a step of removing the sheets 30, 40, 50
Hereinafter, each of the above steps will be described in order.
As shown in FIG. 1, the chimney T is provided adjacent to the building of the refuse incinerator S. In this embodiment, since the dismantling and removal of the refuse incineration facility S is included in the overall construction, the surroundings of the building are also surrounded by sheets, but are not shown in FIG. The demolition and removal work of the refuse incineration facility S and the demolition and removal work of the chimney T may be performed at the same time, or one of the works may be completed first and then the other may be performed. .
[0026]
In the chimney dismantling work, first, as shown in FIG. 2, a scaffold 10 and a top gantry 20 are constructed around a chimney T, and are surrounded by sheets 30 and 40. The scaffold 10 is assembled from the ground to a height close to the top of the chimney T. The scaffold 10 has a structure in which steel frame frame-assembly scaffolds 11, 12,... 1n each having a height of about 1 to 2 m (see FIG. It is. With this structure, as shown in FIG. 6, as the upper portion of the outer wall A of the chimney T is crushed and removed to lower the height of the chimney, the upper scaffold for assembling is sequentially removed as shown in FIG. The top gantry 20 can be sequentially lowered to a lower position. The periphery of the scaffold 10 is surrounded by a synthetic resin sheet 30 used for a tent or the like.
[0027]
The top mount 20 is an integral steel frame structure as shown in FIG. 8 and has a function of holding the surrounding sheet 40 at the top of the chimney. A function to suspend the high-pressure water washer 60 for cleaning the inside of the chimney and the hydraulic crusher 80 for crushing the outer wall is provided inside. The periphery of the top mount 20 is surrounded by a sheet 40 made of synthetic resin.
[0028]
Next, a work space W shown in FIG. 1 is formed. The work space W has an area and a height that allow a construction vehicle to enter and exit the sheet 30 surrounding the periphery of the scaffold 10 and to scrape demolition debris from the inside of the chimney and carry out the work to the outside. This is an area that is isolated from the outside air. In this embodiment, as shown in FIGS. 1 and 3, a working space W is formed by a steel support column 51, a wire 52, and a synthetic resin sheet 50.
[0029]
Further, by dividing the working space W demolition workshop w ₁ and the passage w _2, provided with a door 53, 54 in the front and rear of the passageway w _2, workers and out of the working space W, Construction Vehicles and machines can be taken in and out, and waste materials after disassembly can be carried out without increasing the air pressure in the working space W. Further, etc. by installing the air shower apparatus for a vehicle or machine washing equipment and workers in the passage w ₂ (both not shown), so as to prevent external contamination.
[0030]
In order to maintain the pressure in the working space W lower than the atmospheric pressure, a suction port 55 is provided in a part of the sheet 50, and the air in the working space W is sucked by an air pump (not shown). The air pump is operated continuously when performing dismantling work, and is operated intermittently during work suspension, so that the inside of the working space W can be maintained at a negative pressure. By sucking the air in the work space W with an air pump, outside air is introduced into the work space W through a small gap between the joints of the sheet 50 and a small gap between the doors w ₁ and w ₂ , and the air is replaced. Is performed, the inside of the work space W can be maintained in a state suitable for work.
[0031]
After the above preparation work is completed, cleaning and demolition work inside the chimney is started.
The first washing operation is an operation in which the high-pressure water washer 60 is inserted into the chimney T to peel off and remove combustion deposits on the inner surface of the refractory brick wall F using high-pressure water. As shown in FIG. 3, a high-pressure water washer 60 for washing the inside of the chimney is suspended from the upper girder 21 of the top gantry 20 into the chimney T via a winch (not shown). The high-pressure water washing machine 60 is a well-known washing machine for washing by spraying high-pressure water from a nozzle tip, and a detailed description of its function and structure is omitted. In this cleaning operation, high-pressure water supplied from the outside through the high-pressure water hose 61 is sprayed on the inner surface of the refractory brick wall F inside the chimney T for cleaning.
[0032]
The washing water containing the burnt ash separated and removed by washing is sent to a wastewater treatment device (not shown) through a pipe (not shown) to remove harmful substances such as the burnt ash and dioxin. Reuse for high pressure water for washing. The wastewater treatment equipment is equipped with a heavy metal repair treatment tank, a coagulation sedimentation tank, and an activated carbon treatment tank. The cleaning water after the treatment is reused as high-pressure water sent to the high-pressure cleaning machine 60 again.
[0033]
After the first cleaning operation, the high-pressure water washer 60 is removed, and then, as shown in FIG. The refractory brick wall F is crushed and removed by a hand breaker. The work gondola 70 is suspended via a winch (not shown) from a beam 71 bridged over the upper end of the chimney, and the worker M gets in and crushes the refractory brick wall F with a hand breaker. The crushed pieces f of the refractory bricks that have fallen to the bottom of the chimney are scraped out from the opening To (see FIG. 2) of the bottom of the chimney by the backhoe B and carried out.
[0034]
Next, a second washing operation is performed. As shown in FIG. 5, a working gondola 70 is inserted into the chimney, and a worker riding on the working gondola 70 sprays high-pressure water supplied from the outside onto the inner surface of the chimney outer wall A, thereby forming a refractory brick wall F. After the removal, the brick powder adhering to the outer wall A is washed away. The washing water containing the brick powder and the like is sent to the wastewater treatment device for treatment as in the case of the first washing operation.
[0035]
After the second washing operation is completed, the work gondola 70 is removed, and the remaining outer wall A is crushed by a hydraulic crusher 80 as shown in FIG. In this operation, the worker M arranged on the uppermost scaffold remotely controls a hydraulic machine body (not shown) installed outside to chain from the beam 22 attached to the upper girder 21 of the top mount 20. This is an operation of operating the hydraulic crusher 80 suspended via a block (not shown) and sequentially crushing the outer wall A by the hydraulic crusher 80. The beam 22 is movable in the direction of the paper surface of FIG. 6 along a girder (not shown), and the outer wall A can be sequentially crushed by moving the chain block in two directions. The hydraulic crusher 80 is a known crusher, and an operator M remotely controls the hydraulic crusher main body by a remote controller. The outer wall A is made of reinforced concrete, and the crushed pieces a are dropped to the bottom of the chimney, and the rebar is cut by the worker M using a cutter, and is similarly dropped to the bottom of the chimney.
[0036]
When the removal of the outer wall A corresponding to the height of the two assembling scaffolds 11 and 12 of the scaffolds 10 stacked in many stages is completed, as shown in FIG. 2), the two-stage assembling scaffolds 11 and 12 are removed, and the top gantry 20 is mounted again on the uppermost assembling scaffold 13. Hereinafter, the operations of crushing the outer wall by the hydraulic device 80, removing the scaffold for assembly, and lowering the top gantry are sequentially repeated (see FIG. 8), and the entire outer wall A is crushed and removed.
[0037]
After the completion of the crushing and removing work of the outer wall A, the crushed pieces f of the refractory brick wall F, the crushed pieces a of the outer wall A, the reinforcing bar pieces, etc., which are primarily accumulated in the working space are carried out, and then the working space W is formed. The strut 51, the wire 52, the sheet 50, the scaffold 10 lowered onto the ground, the top gantry 20, the sheets 30, 40, etc., are cleared and the chimney dismantling operation is completed.
[0038]
【The invention's effect】
(1) By shutting off the surroundings of the chimney including the upper part of the chimney from the outside air, forming a working space that is isolated from the outside air, and performing the chimney dismantling work with the working space lower than the atmospheric pressure. In addition, dust and residual harmful substances generated during the dismantling work are prevented from scattering to the outside.
(2) A series of operations can be performed efficiently by washing the inside of the chimney with a high-pressure water washing machine, crushing and removing the refractory brick inside the chimney, and crushing and removing the remaining outer wall. it can.
[Brief description of the drawings]
FIG. 1 is a plan view showing a state of shielding around a chimney in an embodiment of a chimney dismantling method of the present invention.
FIG. 2 is a perspective view showing a shielding situation around a chimney.
FIG. 3 is an explanatory diagram of a cleaning process of the inside of a chimney.
FIG. 4 is an explanatory view of a step of crushing and removing a refractory brick wall.
FIG. 5 is an explanatory view of a step of cleaning the inner surface of the outer wall.
FIG. 6 is an explanatory view of a step of crushing and removing an outer wall.
FIG. 7 is an explanatory view of a step of crushing and removing the outer wall. FIG. 8 is an explanatory view of a step of crushing and removing the outer wall.
Reference Signs List 10 scaffolds 11 to 14,... 1n assembling scaffold 20 top pedestal 21 upper girder 22 beams 30, 40, 50 sheet 51 struts 52 wires 53, 54 opening and closing door 55 suction port 60 high pressure water washer 61 high pressure water hose 70 work Gondola 71 Beam 80 Hydraulic crusher S Garbage incinerator T Chimney To opening W Work space w ₁ Demolition workplace w ₂ Passage F Fire brick wall f Fire brick crushed pieces A Outer wall a Outer wall crushed pieces B Backhoe Cr Crane M Work Person

Claims

A scaffold is assembled around the chimney, which is an object to be dismantled, to a height close to the top of the chimney, the periphery of the assembled scaffold is surrounded by a first sheet, and a pedestal above the top of the chimney above the topmost scaffold. And surrounding the frame with a second sheet to block the chimney around the outside from outside air, and further surrounding a scaffold around a lower portion of the first sheet with a third sheet. To form a working space that is isolated from the outside air, and with this working space below atmospheric pressure,
(1) a step of cleaning the inside of the chimney; (2) a step of removing the refractory brick inside the chimney; and (3) dismantling the chimney through an operation step including each step of removing the chimney outer wall. Construction method.

The step of cleaning the inside of the chimney is a step of inserting a high-pressure water washer into the inside of the chimney and spraying high-pressure water supplied from the outside onto the inner surface of the refractory brick wall inside the chimney to peel off and remove combustion ash. 1. The chimney dismantling method according to 1.

The step of removing the refractory brick inside the chimney is a step of inserting a working gondola inside the chimney, and a worker riding on the working gondola crushing and separating and removing the refractory brick using a crushing device. 1. The chimney dismantling method according to 1.

The step of removing the chimney outer wall includes inserting a hydraulic crusher inside the chimney, and a worker arranged above the scaffold remotely controls a hydraulic machine body installed outside to remove the outer wall from the hydraulic crusher. The chimney dismantling method according to claim 1, wherein the method is a step of crushing sequentially.

The method for dismantling a chimney according to claim 1, further comprising, after the step of removing the refractory brick inside the chimney, a step of cleaning the inner surface of the chimney outer wall after the removal of the refractory brick.

The step of cleaning the inner surface of the chimney outer wall is performed by inserting a working gondola into the chimney, and a worker riding the working gondola sprays high-pressure water supplied from the outside onto the inner surface of the chimney outer wall, such as brick powder. The chimney dismantling method according to claim 5, which is a step of washing away the deposits.