JP3873486B2

JP3873486B2 - Secondary lining construction method

Info

Publication number: JP3873486B2
Application number: JP31439198A
Authority: JP
Inventors: 和夫佐藤; 康英背野; 明神出; 孝充福井
Original assignee: Okumura Corp
Current assignee: Okumura Corp
Priority date: 1998-05-14
Filing date: 1998-11-05
Publication date: 2007-01-24
Anticipated expiration: 2018-11-05
Also published as: JP2000034892A

Description

【０００１】
【発明の属する技術分野】
本発明は、シールドトンネルに於ける二次覆工の施工法に関する。
【０００２】
【従来技術】
シールド工法によるトンネル構築に際し、一次覆工をセグメントの円環状組立により施工する場合、一次覆工の防水性,防食性,内面平滑性等の覆工機能を確立するために、通常、セグメント一次覆工の内側にコンクリート打設による、所謂二次覆工が施工されている。
【０００３】
【発明が解決しようとする課題】
コンクリート二次覆工の施工は、型枠の組立解体,コンクリートの打設養生など施工が煩雑で、しかもコンクリートの養生硬化を待たなければ型枠を撤去できず、どうしても施工期間が長くなり、施工コスト面の負担が大きかった。
【０００４】
また、コンクリートは耐酸性に乏しく、構築されたシールドトンネルを下水道の暗渠として適用する場合には、下水から発生する酸性ガスにより冒されやすく、二次覆工の防食性が問題になることがあった。
【０００５】
最近、コンクリート打設による二次覆工に代えプラスチック管の継ぎ足しにより二次覆工本体を組み立てた後に裏込めを施す、所謂パイプインパイプ工法適用による二次覆工の施工法が試案されているが、二次覆工は少なくとも口径が２ｍ程度となり大口径となるため、該施工法では、大口径パイプの一次覆工内への搬入に多大の時間と手数を要し、工期延長と施工コスト高の問題は依然として未解決であり、より一層の改善が望まれていた。
【０００６】
本発明は、パイプインパイプ工法適用による二次覆工の施工法において、工期の短縮と施工コストの軽減を計ることを目的としてなされたものである。
【０００７】
【課題を解決するための手段】
本発明は、シールドトンネルの構築に於いて、セグメントによる一次覆工を施した後、二次覆工を施すに際し、一次覆工の内径よりも僅かに小さい有効外径の短筒状のプラスチック円筒体を、軸線を横切る横向き開口状態のもとに一次覆工内の所定部位まで搬入し、搬入後は、開口の向きを軸線方向に戻し一次覆工と一致させ、このような円筒体の搬入と、搬入された円筒体の軸線方向への継ぎ足しを繰り返すことにより二次覆工本体を組み立て、二次覆工本体には、継ぎ足しの間に浮き上がり防止を施し、しかる後に、二次覆工本体と一次覆工との内,外径差に基づく隙間内に裏込めを施すことを特徴とする二次覆工の施工法に係る（以下、第１発明という）。
【０００８】
更に本発明は、シールドトンネルの構築において、セグメントによる一次覆工を施した後、二次覆工を施すに際し、一次覆工の内径よりも小さい幅のプラスチック帯状体を一次覆工内に軸線に沿い搬入し、軸線上において、該帯状体の３６０°の巻回により、一次覆工の内径よりも僅かに小さい外径にして横向き開口の短筒状のプラスチック円筒体を組み立て、組立後、該円筒体の開口の向きを軸線方向に戻し一次覆工と一致させ、このような円筒体の組み立を繰り返しながら円筒体を順次継ぎ足して行くことにより、二次覆工本体を組立て、二次覆工本体には、継ぎ足しの間に浮き上がり防止を施し、しかる後に、二次覆工本体と一次覆工との内,外径差に基づく間隙内に裏込めを施すことを特徴とする二次覆工の施工法に係る（以下、第２発明という）。
【０００９】
【発明の実施の形態】
以下に、本発明の一実施形態を添付図面に基づき説明する。尚全図を通じて、同一符号は実質的に同一部分を示している。
【００１０】
本発明の第１発明に於ける一実施形態が図１〜１７に示されている。本実施形態において、二次覆工の構築には、二次覆工の本体を組み立てるためにプラスチック製円筒体１（図１参照）が使用される。一次覆工ａは施工規模にもよるが、通常は、少なくとも２ｍ程度の内径を有し、したがって、円筒体１としてもかなり大口径のものを使用することが必要になり、円筒形状での施工現場への搬入は嵩張り不便である。
【００１１】
而して、第１発明に於いては、円筒体１の組立は、図１に示すように、シールドトンネル坑外、例えばシールドトンネルの一端側に接続する立坑ｂ内で行なわれる。立坑ｂ内には、帯板状のプラスチック成形材１ａを巻き取ったコイルＡが搬入され、該コイルＡから上記円筒体１の円周長に相当する長さの成形材１ａを切り取り、該成形材１ａを３６０°巻回した後、円周上の継ぎ目１ａ₁（図２参照）を融着、その他ジョイント金具適用等の公知の適宜の手段を適用してジョイントすることにより円筒体１が得られる。このようにして組み立てられた円筒体１は保形性を有し、以後、円筒形状を保持する。
【００１２】
円筒体１の外径は、一次覆工ａとの間に裏込め材の充填空間を形成するために、一次覆工ａの内径より少し小さいことが必要であり、通常は、一次覆工ａの内径の８５〜９５％程度に相当する外径に設定される。
【００１３】
立坑ｂ内で組み立てられた円筒体１は、図３に示すように、二次覆工本体１Ａの組立のために一次覆工ａ内に搬入される。一次覆工内ａへの搬入には、図３に示すように、転動移動手段が適用される。
【００１４】
図４は、一次覆工ａ内への円筒体１の搬入状況を示し、円筒体１は一次覆工ａ内に横向き状態、即ち一次覆工ａと開口向きを一致する正常状態より略々９０°向きを変えた状態の下に設置される。この場合、円筒体１の軸長Ｗがあまり大きすぎると、円筒体１を一次覆工ａ内に横向きに設置することが出来なくなるので、円筒体１は短筒状であることが必要であり、軸長Ｗは、例えば一次覆工ａの内径の２０％〜５０％程度の範囲に設定される。因みに、円筒体１の軸長Ｗが一次覆工ａの内径の２０％に達しない場合には、円筒体１の軸長Ｗがあまりに小さくなりすぎ、一方５０％を超えると一次覆工ａとの内外径差が大きくなりすぎ、いずれも好ましくない。円筒体１の軸長Ｗは、図４に示すように、一次覆工ａ内への設置状態において、該円筒体１の上端を通る一次覆工ａの弦の長さＬより小さいことが必要である
円筒体１は一次覆工ａ内に横向き状態に設置されるので、転動移動手段の適用が可能になり、容易且つ迅速に一次覆工ａ内の所定位置まで搬入することができる。
【００１５】
円筒体１を一次覆工ａ内の所定部位まで転動移動により搬入した後、開口の向きを略々９０°変え正常向きに戻し、先行の円筒体１′の後端側に、例えば接合部材３の適用により接続固定することにより、二次覆工本体１Ａの組立が１ピッチ進行する。
【００１６】
以下、同様に、立坑ｂ内での円筒体１の組立、該円筒体１の一次覆工ａ内への転動移動搬入及び接合部材３適用による円筒体１と先行円筒体１′との接続を順次繰り返すことにより、二次覆工本体１Ａの一スパンの組み立てを終える。尚、円筒体同士の接続は、接合部材３の適用無しに直接行うようにしてもよい。
【００１７】
二次覆工本体１Ａの一スパンの組立を終えた後は、図５,６に示すように、該本体１Ａと一次覆工ａとの間の隙間４の手前側を詰め物５、例えば粘土状の急結セメント,エポキシ樹脂系パテ材等を用いて閉塞し、更に詰め物５の上端領域には、裏込め材充填用ホースの挿通口６をパイプ材等の埋め込みにより予め確保しておく。詰め物５は、裏込め材の注入充填時に於ける裏込め材の流出と比重差による二次覆工本体１Ａの浮き上がりをそれぞれ防止する働きをしている。
【００１８】
詰め物５が硬化した後は、図７に示すように、裏込め材充填用のホース７を挿通口６から本体１Ａと一次覆工ａ間の隙間４内に挿入し、該ホース７を通じ上記隙間４内に裏込め材８、例えばセメントミルクを充填し、充填後、挿通口６を栓体等の適宜の閉塞手段（図示せず）を適用して閉じることにより、図８,９に示すように、一スパンの２次覆工を終える。尚、裏込め注入は、必ずしも全断面注入である必要はなく、場合によっては、下部のみの部分断面注入であっても良い。
【００１９】
次ぎに、二次覆工本体１Ａの最後尾の円筒体１′（図８参照）を基準に、先と同様の手順で一スパンの二次覆工本体１Ａを組み立て、更に裏込めを施すことにより二次覆工を更に一スパン延長することが出来る。
【００２０】
以下、同様に、二次覆工を一スパンずつ延長して行くことにより、一次覆工の全長に亘り二次覆工を施すことが出来る。
【００２１】
このようにして構築された二次覆工は、内周部を構成している本体１Ａの部分がプラスチック製円筒体１から構成されているので、耐酸性ひいては防食性に優れ、特に下水道のように酸性ガスが発生した場合であっても、冒されることがなくなる。
【００２２】
本発明に於いては、図１０に示すように、立坑ｂ内では、成形材１ａを３６０°を少し超えるように、例えば１０〜３０°程度の角度幅でラップ部１ｂ₁が生ずるように巻回して小さい外径の予備筒１ｂを作製し、該予備筒１ｂを結束等により形状拘束した状態で一次覆工ａ内に転動移動により搬入し、しかる後、先行の円筒体１′と接続する直前で、図１１に示すように、形状拘束から解放して３６０°の巻回状態まで戻した後に融着その他適宜のジョイント手段を適用して円筒体１を組み立てるようにしてもよい。このようにすれば、外径縮小により一次覆工ａ内への転動移動搬入が容易になり、またラップ部１ｂ₁を戻すことにより外径が拡大されるので、円筒体１の外径としては、図１に示す場合と実質的に変わらないか、或いは場合によれば、図１に示す場合よりも拡大された外径の円筒体１が得られる。
【００２３】
本発明に於いて、成形材１ａの断面形状及び材質は円筒体１を組み立てることができる限り特に制限はない。成形材１ａは熱可塑性プラスチック、例えばポリ塩化ビニル，ポリエチレン，ポリプロピレン等から円筒体１の軸長Ｗ（図４参照）に相当する幅で帯状長尺に成形され、円筒状巻き取りが可能な程度の可撓性と円筒状組立状態での形状保持が可能な程度の剛性を有し、コイル状に巻き取られた状態で施工現場に搬入される。
【００２４】
図１２に成形材１ａの好ましい一例が示され、該成形材１ａは、内面側が平滑で、外面側には長手方向に延出し幅方向に間隔を存して平行する多数本の例えばＴ型のリブ片９を備え、また両側部には、接合縁部１０を備えている。接合縁部１０は内面側に開口する係止凹条１０ａと該凹条１０ａから外側方へ張り出された突縁１０ｂを備え、該突縁１０ｂは係止凹条１０ａとは段違いにかつ外面側へ位置をずらして形成されている。
【００２５】
図１,２に示すように、成形材１ａを長手方向に３６０°巻回し、この巻回状態に於いて、円周上の継ぎ目１ａ₁を融着等によりジョイントすることにより円筒体１が得られる。
【００２６】
円筒体１,１同士の接続部の構造が図１３に示され、接続には帯状のプラスチック製接合部材３が適用される。図１４に示すように、接合部材３は両側部に、円筒体１の接合縁部１０の係止凹条１０ａに弾性係合可能な係止突条３ａ,３ａを備え、該係止突条３ａを円筒体１の接合縁部１０の係止凹条１０ａに嵌合係止することにより、円筒体１,１同士を接合できる。円筒体１,１の接合手段は図示の構成のものに何等制限されず、その他各種の接合手段を採用でき、接合部材の適用無しに直接接合するようにしてもよいる。
【００２７】
図１３に示すように円筒体１,１同士の接合部の強度並びに円筒体１の保形性向上を目的として、接合部内に補強リング１１を装入設置することが出来る。補強リング１１は、接合部材３と一対の突縁１０ｂ,１０ｂとの間で挟持され、二次覆工の外周面側では突縁１０ｂ,１０ｂ間から外部に露出し、この露出部１１ａには、図１５に示すように、裏込め材の流通口１２が形成され、該流通口１２を通って裏込め材８が接合部材３との間の隙間に流入できるようになっている。
【００２８】
裏込め材の充填時には、二次覆工本体１Ａと裏込め材８との比重の関係によっては、上記本体１Ａが一次覆工ａ内で浮き上がる恐れがあり、このような場合には、適宜の浮き上がり防止手段を適用できる。図１６に、浮き上がり防止手段の一例が示され、二次覆工本体１Ａの１スパンを基準に、選択された少なくとも１つの補強リング１１が連結部材１３を介し一次覆工側に結合固定されている。
【００２９】
補強リング１１は金属、その他硬質プラスチック製であり、二次覆工本体１Ａの組立時には円筒体１と交互に一次覆工ａ内に搬入され、搬入には、図１７に示すように、例えば転動移動手段を適用できる。
【００３０】
裏込め材の充填時には比重差により円筒体１に浮力が発生し、浮力を受けて円筒体１が浮上する傾向となるが、上記補強リング１１はこのような円筒体１の浮上防止に効果がある。
【００３１】
本発明の第２発明が図１８〜３２に示されている。第２発明によれば、プラスチック成形材１ａからの円筒体１の組立が、一次覆工ａ内で行われる点で、第１発明と相違している。以下、第２発明の一実施形態を図１８〜３２に基づき説明する。
【００３２】
図１８，１９は、プラスチック成形材１ａの一次覆工ａ内への搬入状況を示し、該成形材１ａは定尺の帯板状の形態で多数枚が台車１４上に積載され、この積載状態のもとに一次覆工ａ内に搬入される。プラスチック成形材１ａは、例えば工場での押し出し成型時に筒状体１の円周長に相当する長さに裁断され、定尺寸法とされ、一次覆工ａ内では、管軸方向に延出している。また幅は、一次覆工ａ内への搬入を可能とし、更には一次覆工ａ内での円筒体１の組立を可能とするために、一次覆工ａの内径の２０〜５０％程度に相当する幅に設定される。因みに、幅が２０％に達しない場合は、得られる円筒体１の軸長があまりに小さくなりすぎ、一方５０％を超えると、一次覆工ａとの間の内外径差が大きくなりすぎ、いずれも好ましくない。
【００３３】
図２０に示す断面図から明らかなように、成形材１ａは幅方向の一端側に挿し口形成用部１５を、また他端側に受け口形成用部１６を備え、これら形成用部１５，１６間には、Ｔ型のリブ片１７の多数本が長手方向に延出し幅方向に間隔を存して平行するように形成されている。
【００３４】
成形材１ａから円筒体１を組み立てた状態が図１８に示され、円周上の継ぎ目の接合は、第１発明と同様に、例えば融着手段を適用して行えばよい。組み立てられた円筒体１の一端側には挿し口形成用部１５から挿し口１５ａが、また他端側には、受け口形成用部１６から受け口１６ａが形成される（図３１参照）。
【００３５】
一次覆工ａ内で組み立てられた円筒体１は短筒状で、図２１に示すように、一次覆工１内で転動移動が可能であり、第１発明と同様に、一次覆工ａ内への円筒体１の搬入を迅速確実に行うことができる。
【００３６】
一次覆工ａ内に於いて、３つの円筒体１の接続を終えた直後の状態が図２２に示されている。一次覆工ａは円環状組立の鋼製セグメントから構築されており、一次覆工ａの底部には、レベリング部材１９が下端部とその両側の都合３ヶ所に取り付けられている。
【００３７】
レベリング部材１９は、例えば鋼製のアングル材から構成され、管軸方向に延出した状態で、例えば溶接手段を適用して一次覆工ａ側に固着され、この固着状態に於いては、図２３に示すように、それぞれ断面逆Ｌ形で同じ方向を向き、下記の下浮き上がり防止部材２０の係止部２１を係止できる構成になっている。
【００３８】
図２２から明らかなように、３つの円筒体１の接続を終えた直後の状態に於いては、第３の円筒体１の上端からは前方に向け第３の上浮き上がり防止材２２の前接続端部２３が突出している。このような前接続端部２３の突出を可能とするために、第１の上浮き上がり防止材２２′は円筒体１より長さの若干大きいものが使用され、また後続の上浮き上がり防止材２２を支持するために、一次覆工ａ側に溶接等の手段を適用して固着されている。後続の上浮き上がり防止材２２は円筒体１と同じ長さのものが使用される。上浮き上がり防止材２２，２２′は一次覆工ａと円筒体１との内外径差を埋めることができる上下幅を持っている。
【００３９】
図２２に示す状態で、最初に第４の上浮き上がり防止材２２が第３の上浮き上がり防止材２２に接続される。この接続は、図２４，２５に示すように、第４上浮き上がり防止材２２の後端側に備えた差込片２４を第３上浮き上がり防止材２２の前接続端部２３に備えた凹部２３ａに挿着することにより行われる。
【００４０】
図２６に示すように、上浮き上がり防止材２２に一次覆工ａ側のＬ形リブａ₁に対する抱持部２５を備えることにより、該防止材２２に振れ止めを施すことができる。
【００４１】
一方、第３の円筒体１の下部には、下浮き上がり防止材２０が取り付けられる。下浮き上がり防止材２０は、図２７に示すように、円弧状を呈し下面側には下端部とその両側との３ヶ所にＬ形の係止部２１が設けられ、係止部２１，２１間の間隔はレベリング部材１９，１９間の取り付け間隔に等しく、且つ向きがレベリング部材１９とは逆向きになっており、図２８に示すように、レベリング部材１９に係止することにより、レベリング部材１９を介し一次覆工ａ側に取り付け固定できる構成になっている。このような取り付け固定は、溶接手段を適用して行ってもよい。
【００４２】
図２９に示すように、下浮き上がり防止材２０は略々帯板状であり、リブ片１７に基づき円筒体１の挿し口１５ａの外周りに生ずる周隙２６内に差込が可能である。
【００４３】
図２８に仮想線で示すように、レベリング部材１９と係止部２１との位置を僅かにずらした状態で、上記周隙２６内に下浮き上がり防止材２０を差し込んだ後、下浮き上がり防止材２０を所定角度回動することにより、係止部２１をレベリング部材１９に係止固定することができる。
【００４４】
図２９に示すように、下浮き上がり防止材２０を円筒体１の挿し口１５ａの外周りの周隙２６内に差込み且つ回動操作によりレベリング部材１９に固定すると、該防止材２０の一端側２０ａが挿し口１５ａ近傍のＴ形リブ片１７ａに係止し、よって第３の円筒体１は該防止材２０並びにレベリング部材１９を介し一次覆工ａ側に固定され、浮き上がり防止される。下浮き上がり防止材２０の他端側２０ｂは、挿し口１５ａより外方へ突出している。
【００４５】
図３０に示すように、第３の円筒体１の上下に浮き上がり防止材２２，２０を取り付けた後、第４の円筒体１を受け口１６ａに於いて第３の円筒体１の挿し口１５ａに差し込み接続すると、図３１に示すように、第４の円筒体１の受け口１６ａ近傍のＴ形リブ片１７ｂに下浮き上がり防止材２０の他端側２０ｂが係止し、よって第４の円筒体１の受け口１６ａ側が第３の円筒体１の挿し口１５ａ側と同様に浮き上がり防止される。
【００４６】
下浮き上がり防止材２０は剛性部材、例えば金属から構成され、図２９に示すように、円筒体１の挿し口１５ａの下半部を外側から覆い、下半部の強度を強化している。よって、裏込め材の注入充填時に比重差により、円筒体１が下側から押し上げ力を受けても、該円筒体１の下半部が変形することがなくなる。
【００４７】
図３２に示すように、第４円筒体の接続で二次覆工本体１Ａの組立が一ピッチ進行し、以下、上下の浮き上がり防止材２０，２２の取り付けと次の円筒体１の接続を繰り返すことにより、二次覆工本体１Ａの組立が一ピッチずつ進行して行く。一スパンの二次覆工本体１Ａの組立を終えた後は、第１発明と同様に、裏込めを施すことにより、一スパンの二次覆工の構築を終え、以下、一ピッチずつの二次覆工本体１Ａの組立と一スパンの二次覆工本体１Ａへの裏込めを繰り返すことにより、一次覆工の全長に亘り二次覆工を構築することができる。
【００４８】
【発明の効果】
本発明施工法によれば、円筒体の一次覆工内へのに搬入が簡単容易となり、二次覆工本体の組み立てをこれが大口径であるに拘わらず迅速確実に行うことが可能になり、施工期間の短縮と施工コストの低減を計ることができる。
【図面の簡単な説明】
【図１】本発明の第１発明に於ける施工現場での円筒体の組立状況を示す説明図である。
【図２】同、円筒体の継ぎ目のジョイント状況を示す説明図である。
【図３】同、円筒体の一次覆工内への搬入状況を示す説明図である。
【図４】同、一次覆工内での円筒体の転動移動状況を示す説明図である。
【図５】同、二次覆工本体と一次覆工との間の隙間を詰め物で塞いだ状況を示す説明図である。
【図６】図５を正面側から見た図である。
【図７】同、裏込め作業時の説明図である。
【図８】同、裏込め終了時の状況を示す説明図である。
【図９】同、横断面図である。
【図１０】同、成形材を３６０°を超えて巻回した状況を示す説明図である。
【図１１】同、図１０の状態から３６０°の巻回状態まで戻した状況を示す説明図である。
【図１２】同、成形材の断面形状の一例を示す斜視図である。
【図１３】同、円筒体同士の接続部の部分断面図である。
【図１４】同、円筒体同士の接合に適用される接合部材の一例を示す斜視図である。
【図１５】同、補強リングの断面図である。
【図１６】同、浮き上がり防止手段の一例を示す横断面図である。
【図１７】同、補強リングの一次覆工内への搬入状況を示す説明図である。
【図１８】本発明の第２発明に於ける、帯板状の成形材の一次覆工内への搬入状況を概略的に示す縦断面図である。
【図１９】同、搬入状況を概略的に示す正面図である。
【図２０】同、成形材の断面形状を示す斜視図である。
【図２１】同、成形材からの円筒体の組立状況を概略的に示す断面図である。
【図２２】同、円筒体を３個接続した直後の状況を概略的に示す縦断面図である。
【図２３】同、レベリング部材を取り付け状況を概略的に示す説明図である。
【図２４】同、上浮き上がり防止部材同士の接合直前の状況を概略的に示す説明図である。
【図２５】同、上浮き上がり防止部材の接合後の状況を概略的に示す説明図である。
【図２６】同、上浮き上がり防止部材の振れ止め手段の一例を示す説明図である。
【図２７】同、下浮き上がり防止部材の正面図である。
【図２８】同、下浮き上がり防止材をレベリング部材に取り付け固定した状況を示す説明図である。
【図２９】同、下浮き上がり防止材を円筒体に取り付けた状況を概略的に示す説明図である。
【図３０】同、上下の浮き上がり防止材の取り付けを終えた状況を示す説明図である。
【図３１】同、円筒体に更に他の１つの円筒体を接続した状況を概略的に示す説明図である。
【図３２】同、二次覆工本体の組立が一ピッチ進行した状況を示す説明図である。
【付号の説明】
１円筒体
１Ａ二次覆工本体
１ａプラスチック製成形材
２欠番
３接合部材
４隙間
５詰め物
６挿通口
７ホース
８裏込め材
９補強リブ
１０接合縁部
１１補強リング
１２流通口
１３連結部材
１４台車
１５挿し口形成用部
１５ａ挿し口
１６受け口形成用部
１６ａ受け口
１７リブ片
１８欠番
１９レベリング部材
２０下浮き上がり防止材
２１係止部
２２上浮き上がり防止材
２３接続端部
２４差込片
２５抱持部
２６周隙[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a secondary lining construction method in a shield tunnel.
[0002]
[Prior art]
When constructing a tunnel by the shield method, when constructing the primary lining by the annular assembly of segments, in order to establish the lining function such as waterproofness, corrosion resistance, inner surface smoothness etc. A so-called secondary lining by concrete placement is installed inside the work.
[0003]
[Problems to be solved by the invention]
Construction of secondary concrete lining is complicated, such as assembling and dismantling the formwork and placing concrete curing, and the formwork cannot be removed without waiting for the concrete to harden. Cost burden was great.
[0004]
In addition, concrete is poor in acid resistance, and when the constructed shield tunnel is used as a sewer for sewers, it is easily affected by the acid gas generated from the sewage, and the corrosion resistance of the secondary lining may become a problem. It was.
[0005]
Recently, a secondary lining construction method by applying the so-called pipe-in-pipe method has been devised, in which a secondary lining body is assembled by adding a plastic pipe instead of a secondary lining by concrete placement, and then backfilling is performed. However, since the secondary lining has a large diameter of at least about 2 m, this construction method requires a lot of time and labor to bring the large diameter pipe into the primary lining, extending the construction period and construction costs. The high problem is still unresolved and further improvements have been desired.
[0006]
The present invention has been made for the purpose of shortening the construction period and reducing the construction cost in the construction method of secondary lining by applying the pipe-in-pipe construction method.
[0007]
[Means for Solving the Problems]
In the construction of a shield tunnel, the present invention provides a short cylindrical plastic cylinder having an effective outer diameter slightly smaller than the inner diameter of the primary lining when the secondary lining is performed after the primary lining by the segment. The body is transported to a predetermined site in the primary lining under the condition of the lateral opening across the axis, and after loading, the direction of the opening is returned to the axial direction to match the primary lining, and such a cylindrical body is transported. Then, the secondary lining main body is assembled by repeating the addition of the loaded cylinder in the axial direction, and the secondary lining main body is prevented from rising during the addition, and then the secondary lining main body And a primary lining, and a secondary lining construction method characterized in that backfilling is performed in a gap based on the outer diameter difference (hereinafter referred to as a first invention).
[0008]
Furthermore, in the construction of a shield tunnel, the present invention provides a plastic strip having a width smaller than the inner diameter of the primary lining in the primary lining when the secondary lining is performed after the primary lining by the segment. Along the axis, by assembling the belt-like body at 360 °, an outer diameter slightly smaller than the inner diameter of the primary lining is assembled, and a short cylindrical plastic cylinder having a lateral opening is assembled. The direction of the opening of the cylindrical body is returned to the axial direction to coincide with the primary lining, and the secondary body is assembled by sequentially adding the cylindrical body while repeating the assembling of the cylindrical body, and the secondary lining is assembled. The main body is prevented from being lifted during the addition, and then a secondary lining is provided in the gap between the secondary lining main body and the primary lining based on the outer diameter difference. Related to the construction method (hereinafter referred to as the second That bright).
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Throughout the drawings, the same reference numerals indicate substantially the same parts.
[0010]
One embodiment of the first invention of the present invention is shown in FIGS. In the present embodiment, a plastic cylinder 1 (see FIG. 1) is used to construct the secondary lining for assembling the secondary lining main body. Although the primary lining a depends on the construction scale, it usually has an inner diameter of at least about 2 m. Therefore, it is necessary to use a cylinder 1 having a considerably large diameter, and construction in a cylindrical shape is required. Carrying on site is bulky and inconvenient.
[0011]
Thus, in the first invention, assembling of the cylindrical body 1 is performed outside the shield tunnel, for example, in the shaft b connected to one end of the shield tunnel, as shown in FIG. A coil A around which a strip-shaped plastic molding material 1a is wound is carried into the shaft b, and a molding material 1a having a length corresponding to the circumferential length of the cylindrical body 1 is cut out from the coil A. After the material 1a is wound 360 °, the cylindrical seam 1 is obtained by fusing the seam 1a ₁ (see FIG. 2) on the circumference and jointing by applying other appropriate means such as joint metal fittings. It is done. The cylindrical body 1 assembled in this way has shape retention, and thereafter retains the cylindrical shape.
[0012]
The outer diameter of the cylindrical body 1 needs to be a little smaller than the inner diameter of the primary lining a in order to form a filling space for the backfill material with the primary lining a. Is set to an outer diameter corresponding to about 85 to 95% of the inner diameter.
[0013]
As shown in FIG. 3, the cylindrical body 1 assembled in the shaft b is carried into the primary lining a for assembly of the secondary lining main body 1A. As shown in FIG. 3, rolling movement means is applied to carry in the primary lining a.
[0014]
FIG. 4 shows a situation where the cylindrical body 1 is carried into the primary lining a, and the cylindrical body 1 is in a sideways state in the primary lining a, that is, approximately 90 from a normal state in which the primary lining a and the opening direction coincide. ° Installed under a changed orientation. In this case, if the axial length W of the cylindrical body 1 is too large, the cylindrical body 1 cannot be installed sideways in the primary lining a. Therefore, the cylindrical body 1 needs to have a short cylindrical shape. The shaft length W is set, for example, in a range of about 20% to 50% of the inner diameter of the primary lining a. Incidentally, when the axial length W of the cylindrical body 1 does not reach 20% of the inner diameter of the primary lining a, the axial length W of the cylindrical body 1 becomes too small. The difference between the inner and outer diameters becomes too large, which is not preferable. As shown in FIG. 4, the axial length W of the cylindrical body 1 needs to be smaller than the length L of the string of the primary lining a passing through the upper end of the cylindrical body 1 in the installed state in the primary lining a. Since the cylindrical body 1 is installed in a sideways state in the primary lining a, it is possible to apply a rolling movement means, and it can be easily and quickly carried to a predetermined position in the primary lining a.
[0015]
After carrying the cylindrical body 1 by rolling movement to a predetermined site in the primary lining a, the direction of the opening is changed by approximately 90 ° to return to the normal direction, and, for example, a joining member is placed on the rear end side of the preceding cylindrical body 1 ′. As a result of connecting and fixing by applying 3, the assembly of the secondary lining main body 1A proceeds by one pitch.
[0016]
Hereinafter, similarly, the cylindrical body 1 is assembled in the shaft b, the rolling movement is carried into the primary lining a of the cylindrical body 1, and the connection between the cylindrical body 1 and the preceding cylindrical body 1 ′ by applying the joining member 3. Are sequentially repeated to complete the assembly of one span of the secondary lining main body 1A. In addition, you may make it connect the cylindrical bodies directly, without application of the joining member 3. FIG.
[0017]
After the assembly of one span of the secondary lining main body 1A, as shown in FIGS. 5 and 6, the front side of the gap 4 between the main body 1A and the primary lining a is stuffed 5 such as clay. In the upper end region of the stuffing 5, an insertion port 6 for a backfilling material filling hose is secured in advance by embedding a pipe material or the like. The stuffing 5 functions to prevent the secondary lining main body 1A from floating due to the outflow of the backfilling material and the difference in specific gravity during the filling of the backfilling material.
[0018]
After the filling 5 is cured, as shown in FIG. 7, a hose 7 for filling the backfill material is inserted into the gap 4 between the main body 1 </ b> A and the primary lining a through the insertion port 6, and the gap is passed through the hose 7. As shown in FIGS. 8 and 9, a backfill material 8 such as cement milk is filled in 4, and after filling, the insertion opening 6 is closed by applying an appropriate closing means (not shown) such as a plug. Finally, one span of secondary lining is completed. The backfill injection does not necessarily have to be a full cross-sectional injection, and may be a partial cross-sectional injection of only the lower part depending on the case.
[0019]
Next, assembling the secondary lining main body 1A with one span in the same procedure as described above with reference to the last cylindrical body 1 '(see FIG. 8) of the secondary lining main body 1A, and further backfilling The secondary lining can be further extended by one span.
[0020]
Similarly, the secondary lining can be applied over the entire length of the primary lining by extending the secondary lining one span at a time.
[0021]
In the secondary lining constructed in this way, the portion of the main body 1A constituting the inner peripheral portion is composed of the plastic cylindrical body 1, so that it is excellent in acid resistance and thus anticorrosion, particularly in the case of sewerage. Even if acid gas is generated, it will not be affected.
[0022]
In the present invention, as shown in FIG. 10, in the shaft b, winding is performed so that a lap portion 1b ₁ is generated with an angular width of, for example, about 10 to 30 ° so as to slightly exceed 360 ° of the molding material 1a. Rotate to produce a spare cylinder 1b with a small outer diameter, and carry the rolling cylinder into the primary lining a in a state where the spare cylinder 1b is constrained by binding or the like, and then connect to the preceding cylinder 1 '. As shown in FIG. 11, the cylindrical body 1 may be assembled by applying fusion or other appropriate joint means after releasing from the shape restraint and returning to the 360 ° winding state immediately before the operation. By this way, the rolling movement carried in the reduced outer diameter to the primary lining a becomes easy, since the outer diameter is enlarged by returning the lap portion 1b _1, as the outer diameter of the cylindrical body 1 Is substantially the same as in the case shown in FIG. 1, or in some cases, a cylindrical body 1 having an outer diameter larger than that in the case shown in FIG. 1 is obtained.
[0023]
In the present invention, the cross-sectional shape and material of the molding material 1a are not particularly limited as long as the cylindrical body 1 can be assembled. The molding material 1a is formed from a thermoplastic plastic such as polyvinyl chloride, polyethylene, polypropylene or the like into a strip-like shape having a width corresponding to the axial length W of the cylindrical body 1 (see FIG. 4), and can be wound in a cylindrical shape. It has such a degree of flexibility that it can hold the shape in a cylindrical assembly state, and is carried into the construction site in a state of being wound in a coil shape.
[0024]
FIG. 12 shows a preferred example of the molding material 1a. The molding material 1a has a plurality of, for example, T-shaped ones having a smooth inner surface side and extending on the outer surface side in the longitudinal direction and spaced in the width direction. Rib pieces 9 are provided, and joint edges 10 are provided on both sides. The joining edge portion 10 includes a locking groove 10a that opens to the inner surface side, and a protruding edge 10b that protrudes outward from the groove 10a. The protruding edge 10b is different from the locking groove 10a and has an outer surface. The position is shifted to the side.
[0025]
As shown in FIGS. 1 and 2, a cylindrical body 1 is obtained by winding a forming material 1a 360 ° in the longitudinal direction and jointing the seam 1a ₁ on the circumference by fusion or the like in this winding state. It is done.
[0026]
The structure of the connecting portion between the cylindrical bodies 1 and 1 is shown in FIG. 13, and a strip-shaped plastic joining member 3 is applied for connection. As shown in FIG. 14, the joining member 3 is provided with locking protrusions 3 a and 3 a that can elastically engage with the locking grooves 10 a of the bonding edge 10 of the cylindrical body 1 on both sides, and the locking protrusions The cylindrical bodies 1 and 1 can be joined to each other by fitting and locking 3 a to the locking recess 10 a of the joining edge 10 of the cylindrical body 1. The joining means of the cylindrical bodies 1 and 1 is not limited to the one shown in the figure, and various other joining means can be employed, and the joining may be performed directly without application of a joining member.
[0027]
As shown in FIG. 13, the reinforcing ring 11 can be installed in the joint for the purpose of improving the strength of the joint between the cylindrical bodies 1 and 1 and improving the shape retention of the cylindrical body 1. The reinforcing ring 11 is sandwiched between the joining member 3 and the pair of projecting edges 10b and 10b, and is exposed to the outside from between the projecting edges 10b and 10b on the outer peripheral surface side of the secondary lining. As shown in FIG. 15, a back-filling material flow port 12 is formed, and the back-filling material 8 can flow into the gap between the joining member 3 through the flow port 12.
[0028]
When filling the backfill material, depending on the specific gravity relationship between the secondary lining main body 1A and the backfilling material 8, the main body 1A may be lifted in the primary lining a. Lifting prevention means can be applied. FIG. 16 shows an example of the lifting prevention means. At least one reinforcing ring 11 selected on the basis of one span of the secondary lining main body 1A is coupled and fixed to the primary lining side via the connecting member 13. Yes.
[0029]
The reinforcing ring 11 is made of metal or other hard plastic. When the secondary lining main body 1A is assembled, the reinforcing ring 11 is carried into the primary lining a alternately with the cylindrical body 1. For example, as shown in FIG. Dynamic moving means can be applied.
[0030]
When the backfill material is filled, buoyancy is generated in the cylindrical body 1 due to the difference in specific gravity, and the cylindrical body 1 tends to float by receiving the buoyancy. However, the reinforcing ring 11 is effective in preventing the floating of the cylindrical body 1. is there.
[0031]
A second invention of the present invention is shown in FIGS. According to the 2nd invention, the assembly of the cylindrical body 1 from the plastic molding material 1a is performed in the primary lining a, and is different from the 1st invention. Hereinafter, an embodiment of the second invention will be described with reference to FIGS.
[0032]
FIGS. 18 and 19 show the state of carrying the plastic molding material 1a into the primary lining a. The molding material 1a is loaded on the carriage 14 in the form of a regular strip, and this loading state. Is carried into the primary lining a. The plastic molding material 1a is cut into a length corresponding to the circumferential length of the cylindrical body 1 at the time of extrusion molding at a factory, for example, and is formed into a fixed size. In the primary lining a, the plastic molding material 1a extends in the tube axis direction. Yes. Further, the width is about 20 to 50% of the inner diameter of the primary lining a in order to enable the carrying into the primary lining a and further to assemble the cylindrical body 1 in the primary lining a. The corresponding width is set. Incidentally, when the width does not reach 20%, the axial length of the obtained cylindrical body 1 becomes too small. On the other hand, when it exceeds 50%, the difference between the inner and outer diameters with the primary lining a becomes too large. Is also not preferred.
[0033]
As is clear from the cross-sectional view shown in FIG. 20, the molding material 1 a includes an insertion port forming portion 15 on one end side in the width direction and a receiving port forming portion 16 on the other end side. In between, a large number of T-shaped rib pieces 17 are formed so as to extend in the longitudinal direction and be parallel to each other with a gap in the width direction.
[0034]
A state in which the cylindrical body 1 is assembled from the molding material 1a is shown in FIG. 18, and joining of the seam on the circumference may be performed by applying, for example, a fusion means as in the first invention. An insertion port 15a is formed from the insertion port forming portion 15 on one end side of the assembled cylindrical body 1, and a receiving port 16a is formed from the reception port forming portion 16 on the other end side (see FIG. 31).
[0035]
The cylindrical body 1 assembled in the primary lining a has a short cylindrical shape, and as shown in FIG. 21, can be rolled and moved in the primary lining 1, and as in the first invention, the primary lining a The cylindrical body 1 can be carried in quickly and reliably.
[0036]
FIG. 22 shows a state immediately after the connection of the three cylindrical bodies 1 is completed in the primary lining a. The primary lining a is constructed from a steel segment of an annular assembly, and leveling members 19 are attached to the bottom of the primary lining a at three locations on the lower end and on both sides thereof.
[0037]
The leveling member 19 is made of, for example, a steel angle material, and is fixed to the primary lining a side by applying, for example, welding means in a state of extending in the pipe axis direction. 23, each has an inverted L-shaped cross section and is directed in the same direction, so that the locking portion 21 of the lower lifting prevention member 20 described below can be locked.
[0038]
As is apparent from FIG. 22, in the state immediately after the connection of the three cylindrical bodies 1 is completed, the front connection of the third upper anti-lifting material 22 is directed forward from the upper end of the third cylindrical body 1. The end 23 protrudes. In order to allow the front connection end 23 to protrude, the first upper lifting prevention member 22 ′ having a length slightly longer than that of the cylindrical body 1 is used, and the subsequent upper lifting prevention member 22 is used as the first upper lifting prevention member 22. In order to support, it is fixed to the primary lining a side by applying means such as welding. The succeeding uplifting prevention material 22 has the same length as the cylindrical body 1. The upper lifting prevention materials 22, 22 ′ have a vertical width that can fill the difference between the inner and outer diameters of the primary lining a and the cylindrical body 1.
[0039]
In the state shown in FIG. 22, first, the fourth upper lifting prevention member 22 is connected to the third upper lifting prevention member 22. As shown in FIGS. 24 and 25, this connection is achieved by a recess 23 a provided with an insertion piece 24 provided on the rear end side of the fourth upper lifting prevention member 22 at the front connection end 23 of the third upper lifting prevention member 22. It is done by inserting it into.
[0040]
As shown in FIG. 26, by providing the holding member 25 for the L-shaped rib a ₁ on the primary lining a side in the upper lifting prevention member 22, the prevention member 22 can be prevented from shaking.
[0041]
On the other hand, a lower lifting prevention material 20 is attached to the lower portion of the third cylindrical body 1. As shown in FIG. 27, the lower lifting prevention material 20 has an arc shape, and is provided with L-shaped locking portions 21 on the lower surface side and three sides of the lower surface side, between the locking portions 21 and 21. Is equal to the mounting interval between the leveling members 19 and 19, and the direction is opposite to that of the leveling member 19, and the leveling member 19 is engaged with the leveling member 19 as shown in FIG. It is the structure which can be attached and fixed to the primary lining a side via. Such mounting and fixing may be performed by applying welding means.
[0042]
As shown in FIG. 29, the lower lifting prevention member 20 is substantially in the shape of a strip plate, and can be inserted into the circumferential space 26 generated around the insertion opening 15 a of the cylindrical body 1 based on the rib piece 17.
[0043]
As indicated by phantom lines in FIG. 28, after the lower lifting prevention member 20 is inserted into the circumferential space 26 with the leveling member 19 and the locking portion 21 being slightly displaced, the lower lifting prevention member 20 is inserted. Can be locked and fixed to the leveling member 19.
[0044]
As shown in FIG. 29, when the lower lifting prevention member 20 is inserted into the peripheral space 26 around the insertion opening 15a of the cylindrical body 1 and fixed to the leveling member 19 by a turning operation, one end side 20a of the prevention member 20 is provided. Is locked to the T-shaped rib piece 17a in the vicinity of the insertion opening 15a, so that the third cylindrical body 1 is fixed to the primary lining a side through the prevention member 20 and the leveling member 19, and is prevented from being lifted. The other end side 20b of the lower lifting prevention member 20 protrudes outward from the insertion opening 15a.
[0045]
As shown in FIG. 30, after the anti-lifting materials 22 and 20 are attached to the top and bottom of the third cylindrical body 1, the fourth cylindrical body 1 is inserted into the insertion port 15a of the third cylindrical body 1 at the receiving port 16a. When inserted and connected, as shown in FIG. 31, the other end side 20 b of the lower lifting prevention member 20 is locked to the T-shaped rib piece 17 b in the vicinity of the receiving port 16 a of the fourth cylindrical body 1, and thus the fourth cylindrical body 1. As with the insertion port 15a side of the third cylindrical body 1, the receiving port 16a side is prevented from rising.
[0046]
The lower lift prevention member 20 is made of a rigid member, for example, metal, and as shown in FIG. 29, covers the lower half portion of the insertion opening 15a of the cylindrical body 1 from the outside, thereby strengthening the strength of the lower half portion. Therefore, even when the cylindrical body 1 receives a push-up force from the lower side due to the difference in specific gravity during the filling and filling of the backfill material, the lower half of the cylindrical body 1 is not deformed.
[0047]
As shown in FIG. 32, the assembly of the secondary lining main body 1A proceeds by one pitch by connecting the fourth cylindrical body, and thereafter, the attachment of the upper and lower lifting prevention materials 20 and 22 and the connection of the next cylindrical body 1 are repeated. As a result, the assembly of the secondary lining main body 1A proceeds one pitch at a time. After finishing the assembly of the one-span secondary lining body 1A, as in the first aspect of the invention, the construction of the one-span secondary lining is completed by applying backfilling. By repeating the assembly of the next lining main body 1A and backfilling into the secondary lining main body 1A of one span, a secondary lining can be constructed over the entire length of the primary lining.
[0048]
【The invention's effect】
According to the construction method of the present invention, it becomes easy to carry into the primary lining of the cylindrical body, and it becomes possible to quickly and surely assemble the secondary lining main body regardless of its large diameter, The construction period can be shortened and the construction cost can be reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an assembly state of a cylindrical body at a construction site in the first invention of the present invention.
FIG. 2 is an explanatory view showing a joint state of a joint of a cylindrical body.
FIG. 3 is an explanatory view showing a state of carrying a cylindrical body into a primary lining.
FIG. 4 is an explanatory view showing a rolling movement situation of the cylindrical body in the primary lining.
FIG. 5 is an explanatory view showing a situation in which the gap between the secondary lining main body and the primary lining is closed with padding.
6 is a diagram of FIG. 5 viewed from the front side.
FIG. 7 is an explanatory view at the time of backfilling work.
FIG. 8 is an explanatory diagram showing a situation at the end of backfilling.
FIG. 9 is a cross-sectional view of the same.
FIG. 10 is an explanatory view showing a situation where the molding material is wound over 360 °.
11 is an explanatory view showing a state where the state shown in FIG. 10 is returned to the 360 ° winding state. FIG.
FIG. 12 is a perspective view showing an example of a cross-sectional shape of the molding material.
FIG. 13 is a partial cross-sectional view of a connecting portion between cylindrical bodies.
FIG. 14 is a perspective view showing an example of a joining member applied to joining cylindrical bodies.
FIG. 15 is a sectional view of the reinforcing ring.
FIG. 16 is a cross-sectional view showing an example of the floating prevention means.
FIG. 17 is an explanatory view showing a situation where the reinforcing ring is carried into the primary lining.
FIG. 18 is a longitudinal sectional view schematically showing a state of carrying a strip plate-shaped molding material into a primary lining in the second invention of the present invention.
FIG. 19 is a front view schematically showing the loading situation.
FIG. 20 is a perspective view showing a cross-sectional shape of the molding material.
FIG. 21 is a cross-sectional view schematically showing an assembly state of a cylindrical body from a molding material.
FIG. 22 is a longitudinal sectional view schematically showing a state immediately after connecting three cylindrical bodies.
FIG. 23 is an explanatory view schematically showing a state in which the leveling member is attached.
FIG. 24 is an explanatory view schematically showing a state immediately before joining of the up-lifting prevention members.
FIG. 25 is an explanatory view schematically showing a state after joining of the up-lifting prevention member.
FIG. 26 is an explanatory view showing an example of an anti-swaying means for the upper lifting prevention member.
FIG. 27 is a front view of the lower lifting prevention member.
FIG. 28 is an explanatory view showing a state in which the lower lifting prevention material is attached and fixed to the leveling member.
FIG. 29 is an explanatory view schematically showing a state in which the bottom lifting prevention material is attached to the cylindrical body.
FIG. 30 is an explanatory view showing a situation where the attachment of the upper and lower lifting prevention materials is finished.
FIG. 31 is an explanatory view schematically showing a state in which another cylindrical body is further connected to the cylindrical body.
FIG. 32 is an explanatory view showing a state where the assembly of the secondary lining main body has progressed one pitch.
[Explanation of number]
DESCRIPTION OF SYMBOLS 1 Cylindrical body 1A Secondary lining main body 1a Plastic molding material 2 Missing number 3 Joining member 4 Crevice 5 Filling material 6 Insertion port 7 Hose 8 Backfill material 9 Reinforcement rib 10 Joining edge 11 Reinforcement ring 12 Distribution port 13 Connecting member 14 Cart 15 Inserting Portion Forming Part 15a Inserting Port 16 Receptacle Forming Part 16a Receptacle 17 Rib Piece 18 Notch 19 Leveling Member 20 Lower Lifting Prevention Material 21 Locking Part 22 Upper Lifting Prevention Material 23 Connection End 24 Insertion Piece 25 Holding Part 26 Gap

Claims

In constructing a shield tunnel, after applying the primary lining by the segment, when applying the secondary lining, a short cylindrical plastic cylinder having an effective outer diameter slightly smaller than the inner diameter of the primary lining is In the state of the sideways opening that crosses the primary lining, it is carried to a predetermined site in the primary lining, and after loading, the direction of the opening is returned to the axial direction to match the primary lining primary lining. The secondary lining main body is assembled by repeating the addition of the loaded cylindrical body in the axial direction, and the secondary lining main body is prevented from rising during the addition, and then the secondary lining main body and A secondary lining construction method characterized by backfilling in the gap based on the outer diameter difference with the primary lining.

The construction method according to claim 1, wherein the plastic cylindrical body is assembled to a regular outer diameter by winding 360 ° from a strip-shaped plastic molding material outside the shield tunnel mine.

Outside the shield tunnel, the plastic cylinder is first assembled from a strip-shaped plastic molding material to an intermediate body smaller than the normal outer diameter by winding slightly over 360 °, and the primary lining in this intermediate state Means that it is loaded to a predetermined site in the primary lining under a sideways state in which the direction of the opening is 90 ° different, and after loading, the cylinder is assembled by returning to the regular outer diameter while maintaining the direction. The construction method according to claim 1, wherein the construction method is characterized.

In constructing a shield tunnel, after applying the primary lining by the segment, when applying the secondary lining, a plastic strip having a width smaller than the inner diameter of the primary lining is carried into the primary lining along the axis, On the wire, a 360-degree winding of the belt-like body assembles a short cylindrical plastic cylinder having an outer diameter slightly smaller than the inner diameter of the primary lining, and after assembly, after assembly, The direction is returned to the axial direction to match the primary lining, and the cylinder is sequentially added while repeating the assembling of the cylinder, thereby assembling the secondary lining body and adding the secondary lining to the secondary lining body. The secondary lining construction method is characterized in that it is prevented from rising between the two, and then backfilling is performed in the gap based on the outer diameter difference between the secondary lining main body and the primary lining.

The construction method according to any one of claims 1 to 4, wherein a reinforcing means for maintaining the shape of the cylindrical body is applied when the cylindrical bodies are connected to each other.

The construction method according to any one of claims 1 to 5, wherein the axial length of the plastic cylindrical body is set to a length corresponding to 20 to 50% of the inner diameter of the primary lining.