JP4037006B2 - Tunnel lining method - Google Patents

Description

【００１４】
そして、前記軽量骨材と増粘剤と水とを混練りする場合における、これらの配合は、例えば、１ｍ³当たり
軽量骨材：２５０kg、 増粘剤：５kg、 水：４９５kgとし、
ミキサー等によって所定の時間混練りする。
【００１５】
この透水性裏込め注入材においては、それをトンネル内壁と、覆工部との間に注入して充填することで、覆工部の背面側に充分な透水性を有し、かつ目詰まりの生じ難い裏込め層が形成される。そして、前記覆工部を透水性を有するものとすることで、地下水が前記裏込め層、覆工部を通してトンネル内に容易に取水される。また、前記透水性裏込め注入材を構成する軽量骨材の比重が１未満であっても、該軽量骨材は前記増粘剤によって、均一に分散され、また、ポンプ圧送によって、トンネル内壁と、覆工部との間に均一かつ確実に注入、充填される。
【００１６】
また、本発明の透水性裏込め注入材は、トンネル内壁と、該トンネル内壁の内側を覆工してなる覆工部との間に注入される裏込め注入材であって、軽量骨材とセメントと水とを混練りしてなり、透水係数を１×１０^-1cm/sec〜５×１０⁰ cm/secとしたものである。
【００１７】
前記透水係数を１×１０^-1cm/sec〜５×１０⁰ cm/secとしたのは、前記の場合と同様の理由によるもので、１×１０^-1cm/sec未満では、透水性裏込め注入材の透水性が悪く、地下水が透水し難くなるからであり、また、５×１０⁰ cm/secを超えると、透水性は良くなるが、その一方で流速が大きくなって、地山の土粒子が移動し易くなって、透水性裏込め注入材に目詰まりを生じるためである。
【００１８】
前記軽量骨材としては、前記の場合と同様に、発泡ガラスビーズが好適に使用される。そして、前記軽量骨材とセメントと水とを混練りする場合における、これらの配合は、例えば、１ｍ³当たり軽量骨材：２３９kg、 セメント：６８kg、 水：４９０kgとし、ミキサー等によって所定の時間混練りする。なお、軽量骨材とセメントと水とを混練りする場合、必要に応じて増粘剤を添加してもよい。増粘剤は、上記のような割合で軽量骨材とセメントと水とを配合する場合には、５kg程度添加する。
【００１９】
この透水性裏込め注入材においては、それをトンネル内壁と、覆工部との間に注入して充填することで、覆工部の背面側に充分な透水性を有し、かつ目詰まりの生じ難い裏込め層が形成される。そして、前記覆工部を透水性を有するものとすることで、地下水が前記裏込め層、覆工部を通してトンネル内に容易に取水される。また、透水性裏込め注入材には、セメントが含まれているので、該透水性裏込め注入材をトンネル内壁と覆工部との間に注入、充填して形成された裏込め層が固化するので、覆工完成後の地山の弛みがより確実に防止される。
【００２０】
本発明のトンネル覆工方法は、地山の掘削により形成されたトンネル内壁の内側に、透水性を有するフィルター層を設けた覆工部材を設置していくことで覆工部を形成するとともに、該覆工部とトンネル内壁との間に、透水性裏込め注入材を注入し充填して裏込め層を形成するトンネルの覆工方法であって、
前記透水性裏込め注入材は、軽量骨材と水と増粘剤又はセメントとを混練してなり、その透水性裏込め注入材の透水係数が１×１０ ^-1 cm/sec 〜５×１０ ⁰ cm/sec であり、
前記地山の透水係数と、前記裏込め層の透水係数と、前記フィルター層の透水係数とが、地山の透水係数＜裏込め層の透水係数＜フィルター層の透水係数、となるように設定されていることを特徴としている。
【００２１】
前記透水性を有する覆工部材としては、例えば、覆工部材本体と、この覆工部材本体に設けられた取水部とを備え、該取水部を、前記覆工部材本体の外周部に形成されて、土砂の流入を防止するフィルター層と、このフィルター層の内側の前記覆工部材本体に形成されて、前記フィルター層を通り抜けた地下水を前記トンネル内に流入させる取水孔とから構成したものが好適に使用される。
【００２２】
本発明のトンネルの覆工方法においては、掘削されたトンネル内壁の内側に、透水性を有する覆工部材を設置していくことで、内部に地下水を取水可能な覆工部が形成され、さらに、該覆工部とトンネル内壁との間に、前記の透水性裏込め注入材を注入して充填することで、覆工部の背面側に充分な透水性を有し、かつ目詰まりの生じ難い裏込め層が形成される。したがって、地下水が前記裏込め層、覆工部を通してトンネル内に容易に取水される。
【００２３】
【発明の実施の形態】
以下、図面を参照して本発明の実施の形態の一例について説明する。
まず、本発明に係る透水性裏込め注入材を説明する前に、トンネル内壁の内側を覆工してなる覆工部について説明する。
図１は、シールド工法によって施工されたトンネルの覆工部Ｆを示す斜視図であり、符号１,２はトンネル覆工部材を示す。該トンネル覆工部材１,２はそれぞれ円弧板状をなすもので、それぞれ鉄筋コンクリートで形成されている。
【００２４】
前記トンネル覆工部材１はそれが４個周方向に接合されることで、開環リングを形成し、この開環リングの開いた部分に前記トンネル覆工部材２をはめ込むことで、一つのリング体３を形成している。そして、このリング体３…をトンネルの軸方向に接合していくことで、前記覆工部Ｆが形成されるようになっている。
【００２５】
前記トンネル覆工部材１は、円弧板状をなす覆工部材本体４と、この覆工部材本体４に設けられた取水部５とを備えて構成されている。
前記覆工部材本体４は、シールド工法において使用されるセグメント４であり、互いに周方向に隣接するセグメント４,４どうしは、図４〜図６に示すように、セグメント継手４ａで接合されており、軸方向に隣接するセグメントどうしはリング継手４ｂで接合されるようになっている。
【００２６】
前記取水部５は、トンネル内への土砂の流入を防止して、該トンネル内に地下水を流入可能にするもので、前記セグメント４の外周部に形成されて、土砂の流入を防止するフィルター層６と、このフィルター層６の内側のセグメント４に形成されて、前記フィルター層６を通り抜けた地下水を前記トンネル内に流入させる取水孔７…とから構成されている。
【００２７】
前記フィルター層６は、図６に示すように、セグメント４の中央部に設けられており、セグメント４の端部はコンクリートで構成されている。このようにすることで、セグメント４の運搬時および組立時にフィルター層６が破損するのを防止することができる。
なお、互いに隣接するセグメント４,４どうしのフィルター層６,６どうしは、図４および図６に示すように、フィルター層連通管８によって連通されており、これによってフィルター層６,６間においては地下水が流通できるようになっている。
【００２８】
前記フィルター層６は透水性を有するもので、図３に示すように、外側に配置された第１フィルター層６ａと、この第１フィルター層６ａの内側に配置された第２フィルター層６ｂとから構成されている。前記第１フィルター層６ａの透水係数は、地山の透水係数の１０〜１００倍程度に設定されており、これによって、地山の土粒子が移動するのを防止することができるので、フィルター層６ａの目詰まりを防止することができる。また、前記第２フィルター層６ｂの透水係数は、第１フィルター層６ａの透水係数より高く設定されており、これによって前記取水孔７に水を集め易くなっている。
【００２９】
また、前記セグメント４のほぼ中央部には、図５および図６に示すように、グラウトホール４ｃが形成されている。このグラウトホール４ｃは、セグメント４と地山との間に、本発明に係る透水性裏込め注入材を注入するための孔であり、前記セグメント４とフィルター層６を貫通して形成されている。
なお、前記グラウトホール４ｃには図示しないグラウトキャップが取り付けられており、このグラウトキャップは、前記透水性裏込め注入材を注入するときは、取り外すようになっている。
【００３０】
前記透水性裏込め注入材は、軽量骨材と増粘剤と水とを混練りしてなるもので、その透水係数は、８×１０^-1cm/sec程度に設定されている。そして、地山周辺の地下水により、注入後は増粘剤の溶出により２×１０⁰cm/sec程度に向上する。
前記軽量骨材は、具体的には、発泡ガラスビーズである。この発泡ガラスビーズは、ガラスを主成分とする完全無機質の焼結体であり、独立気泡を無数に内蔵するハニコウム構造体となっている。
また、前記増粘剤は、具体的には、グアーガムである。
【００３１】
そして、前記軽量骨材と増粘剤と水とを混練りする場合における、これらの配合は、例えば、１ｍ³当たり
軽量骨材：２５０kg、 増粘剤：５kg、 水：４９５kgとし、
ミキサー等によって所定の時間混練りする。
このようにして混練りされた透水性裏込め注入材は、その軽量骨材(発泡ガラスビーズ)の比重が１未満であるが、前記増粘剤(グアーガム)によって、均一に分散されたものとなる。
【００３２】
そして、地山の透水係数と、透水性裏込め注入材を注入してなる裏込め層の透水係数と、フィルター層の透水係数とは、
地山の透水係数＜裏込め層の透水係数＜フィルター層の透水係数
となるように設定されており、各々の透水係数の差は、土粒子の移動を生じさせないように、１００倍程度に抑えられている。
このように各々の透水係数の差を設定することで、地山の土粒子が移動するのを防止することができるので、裏込め層およびフィルター層の目詰まりを防止することができる。
【００３３】
前記取水孔７は、図１〜図６に示すように、一つのセグメント４に、３個形成されており、各取水孔７には、該取水孔７を開閉可能とする止水栓１０が着脱自在に取り付けられている。そして、この止水栓１０は、トンネルの施工完了後に取り外すことで、地下水をトンネル内に流入させるようになっている。
【００３４】
なお、前記トンネル覆工部材２は、図２に示すように、トンネル覆工部材１と同様に、円弧板状をなす覆工部材本体(セグメント)１４と、この覆工部材本体１４に設けられた取水部１５とを備えて構成されており、周方向に隣接するセグメント４とは、図４に示すように、セグメント継手４ａで接合されており、軸方向に隣接するセグメント１４,１４どうしはリング継手４ｂで接合されるようになっている。
【００３５】
また、前記取水部１５はフィルター層１６と取水孔１７とで構成されている。フィルター層１６は、前記フィルター層６と同様に、第１フィルター層１６ａと第２フィルター層１６ｂとで構成されており、その透水係数は前記第１フィルター層６ａ、第２フィルター層６ｂと等しく設定されている。また、前記取水孔１７は、セグメント１４の中央部に一つ形成されており、この取水孔１７には止水栓１０が着脱自在に取り付けられている。さらに、トンネル覆工部材２のフィルター層１６と、該トンネル覆工部材２に周方向において隣接する前記トンネル覆工部材１,１のフィルター層６,６とはそれぞれフィルター層連通管８によって連通されている。
【００３６】
次に、上記構成のトンネル覆工部材１,２および透水性裏込め注入材を使用して、シールド工法によってトンネルを施工していく方法について説明する。
図７に示すように、地盤に立坑２０を施工し、この立坑２０からシールド機２１によって海底下の地盤(地山)を掘削しつつ推進していく。地盤の掘削は、シールド機２１の先端部のカッタ装置２１ａで行い、該シールド機２１内においては、円筒分割体たるセグメント２２を掘削孔の周方向に組み立て、さらにこのセグメント２２の前端に反力をとってシールド機内の推進ジャッキを伸長させることで、シールド機２１を推進させる。また、セグメント２２と地盤との間には、裏込め材２３をセグメント２２に形成されたグラウトホールから注入していく。この裏込め材２３としてはモルタル系材料を使用する。
【００３７】
そして、シールド機２１による掘削、推進、セグメント２２の組立、裏込め材２３の注入を行いつつ、シールド機２１が所定の位置まで掘進したならば、前記トンネル覆工部材１,２を周方向に組み立てるとともに接合することで、リング体を形成し、このリング体に反力をとってシールド機２１を掘進させ、さらに前記リング体の先端面側に、次のトンネル覆工部材１,２を周方向に組み立てるとともに接合して次のリング体を形成し、同時にこのリング体を、既に組み立てられた前記リング体に接合する。なお、前記トンネル覆工部材１,２を組み立てる際には、該トンネル覆工部材１,２に形成された前記取水孔７,１７にはそれぞれ止水栓１０を取り付けておく。
【００３８】
そして、このような工程を所定回数繰り返して行うことで、トンネル覆工部材１,２により掘削孔を筒状に覆工し、その筒体の長さが所定の長さに達したら、該筒体の先端面側において、袋付きセグメント２６を周方向に組み立てるとともに接合する。この袋付きセグメント２６は前記セグメント２２と同様のセグメントの背面側に遮蔽袋を装備したもので、この遮蔽袋は掘削孔の内壁に密接するようになっている。
なお、この袋付きセグメント２６は、前記セグメント２２とトンネル覆工部材１,２との間においても設置する。
そして、前記袋付きセグメント２６を組み立てたならば、前記トンネル覆工部材１,２にそれぞれ形成されたグラウトホールから上述した本発明に係る透水性裏込め注入材２５を注入して、地盤とトンネル覆工部材１,２との間に充填する。この透水性裏込め注入材２５の注入は、前記グラウトホールに図示しないホースを接続し、このホースを介してポンプ圧送することにより行う。
【００３９】
さらに、上記と同様にして、シールド機２１によって掘進して、トンネル覆工部材１,２により掘削孔を筒状に覆工し、その筒体の長さが所定の長さに達したら、前記袋付きセグメント２６を組み立てて、前記トンネル覆工部材１,２のグラウトホールから透水性裏込め注入材２５を注入して、地盤とトンネル覆工部材１,２との間に充填する工程を順次所定回数繰り返して行うことで、地盤内にトンネルを施工していく。
そして、前記トンネルの施工完了後に、前記トンネル覆工部材１,２の取水孔７,１７に取り付けられていた止水栓１０を取り外すことで、取水孔７,１７を開放する。
【００４０】
前記取水孔７,１７を開放すると、地下水(海水)が前記透水性裏込め注入材２５を注入充填することにより形成された裏込め層２７および前記フィルター層６,１６を通って取水孔７,１７からトンネル内に流入し、前記立坑２０に形成された貯留槽２０ａに貯留され、この貯留された海水が水中ポンプ２８によって吸い上げられてパイプ２９ａを通って受水槽２９に貯留される。そして、地下水を所定時間トンネル内に流入させ続けると、前記透水性裏込め注入材２５の増粘剤が溶出し、これによって、透水量がさらに増加することになる。
このように、本例の覆工部材１,２および透水性裏込め注入材２５によって覆工されたトンネルは、集水有孔管と導水管の機能を併せ持っているので、大量の取水を必要とする場合に好適である。
【００４１】
また、前記覆工部材１,２に設けた取水部５,１５を、土砂の流入を防止するフィルター層６,１６と、このフィルター層６,１６を通り抜けた海水を前記トンネル内に流入させる取水孔７,１７とから構成したので、トンネル内への土砂の流入を防止して、海水のみを確実に取水することができる。
【００４２】
さらに、前記取水孔７,１７に、止水栓１０を着脱自在に取り付けたので、トンネルの施工中においては、前記止水栓１０を取り付けておくことで、トンネル施工中における海水の流入を防止でき、トンネルの施工完了後に、前記止水栓１０を取り外して前記取水孔７,１７を開けることで、海水をトンネル内に流入させて取水することができる。
【００４３】
なお、上記の例では、本発明をシールド工法に適用した場合を例にとって説明したが、本発明はこれに限ることなく、推進工法にも適用することができる。
この場合、推進管に、上記と同様に、フィルター層と取水孔とで構成された取水部を設け、さらに、該推進管と地山との間に透水性裏込め注入材を注入して充填すればよい。
【００４４】
また、上記の例では、透水性裏込め注入材として、軽量骨材(発泡ガラスビーズ)と増粘剤(グアーガム)と水とを混練りしてなるものを使用したが、これに代えて、軽量骨材(発泡ガラスビーズ)とセメントと水とを混練りしてなるものを使用してもよい。この場合、水性裏込め注入材をトンネル内壁と覆工部との間に注入、充填して形成された裏込め層が固化するので、覆工完成後の地山の弛みがより確実に防止することができる。
【００４５】
【発明の効果】
以上説明したように、本発明の透水性裏込め注入材によれば、軽量骨材と増粘剤と水とを混練りしてなり、 透水係数を１×１０^-1cm/sec〜５×１０⁰ cm/secとしたので、該透水性裏込め注入材をトンネル内壁と、覆工部との間に注入して充填することで、覆工部の背面側に充分な透水性を有し、かつ目詰まりの生じ難い裏込め層を形成することができる。したがって、前記覆工部を透水性を有するものとすることで、地下水を前記裏込め層、覆工部を通してトンネル内に容易に取水することができる。また、前記透水性裏込め注入材を構成する軽量骨材の比重が１未満であっても、該軽量骨材を前記増粘剤によって、均一に分散することができ、また、ポンプ圧送によって、トンネル内壁と、覆工部との間に均一かつ確実に注入、充填することができる。
【００４６】
また、本発明に係る透水性裏込め注入材によれば、軽量骨材とセメントと水とを混練りしてなり、透水係数を１×１０^-1cm/sec〜５×１０⁰ cm/secとしたので、該透水性裏込め注入材をトンネル内壁と、覆工部との間に注入して充填することで、覆工部の背面側に充分な透水性を有し、かつ目詰まりの生じ難い裏込め層を形成することができる。したがって、前記覆工部を透水性を有するものとすることで、地下水を前記裏込め層、覆工部を通してトンネル内に容易に取水することができる。また、透水性裏込め注入材には、セメントが含まれているので、該透水性裏込め注入材をトンネル内壁と覆工部との間に注入、充填して形成された裏込め層が固化するので、覆工完成後の地山の弛みをより確実に防止することができる。
【００４７】
本発明に係るトンネルの覆工方法によれば、掘削されたトンネル内壁の内側に、透水性を有する覆工部材を設置していくことで、内部に地下水を取水可能な覆工部を容易に形成することができ、さらに、該覆工部とトンネル内壁との間に、請求項１または２記載の透水性裏込め注入材を注入して充填することで、覆工部の背面側に充分な透水性を有し、かつ目詰まりの生じ難い裏込め層を容易に形成することができる。したがって、地下水を前記裏込め層、覆工部を通してトンネル内に容易に取水することができる。
【図面の簡単な説明】
【図１】本発明のトンネルの覆工方法によって施工された覆工部の一例を示すもので、該覆工部を概念的に示す斜視図である。
【図２】同、覆工部を概念的に示す断面図である。
【図３】同、図２における取水部の拡大図である。
【図４】同、覆工部の断面図である。
【図５】同、トンネル覆工部材の側断面図である。
【図６】同、トンネル覆工部材の平面図である。
【図７】本発明のトンネルの覆工方法を説明するためのもので、トンネルの側断面図である。
【図８】従来の取水方式の一例を示すもので、海底下に設置された集水有孔管と、長水路導水管を示す側断面図である。
【符号の説明】
Ｆ 覆工部
１,２ トンネル覆工部材
４,１４ 覆工部材本体(セグメント)
５,１５ 取水部
６,１６ フィルター層
７,１７ 取水孔
１０ 止水栓(開閉部材)
２５ 透水性裏込め注入材
２７ 裏込め層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a backfill injection material injected between a tunnel inner wall excavated by a shield machine or the like and a segment installed inside the tunnel inner wall, and a method of using the backfill injection material. It relates to things that can be taken.
[0002]
[Prior art]
Shield tunnels are classified into those that do not allow water to pass through the tunnel, such as railways, roads, communications, electric power, and gas, and those that allow water to pass through the tunnel, such as water and sewage systems and intake tunnels.
The intake tunnel is for passing water for purposes other than water supply and sewerage, and includes, for example, a water conduit tunnel, and there is a water intake channel that takes in seawater, for example.
[0003]
As an example of the seawater intake system, as shown in FIG. 8, there is a system in which a water collecting perforated pipe 30 installed under the seabed and a long waterway conduit 31 are combined. In this system, the suspended matter is removed by the filtering action by the soil layer, and the seawater flows into the water collecting perforated pipe 30, and this inflowing seawater is stored in the storage tank 32 through the long water channel conduit 31. The stored seawater is sucked up by the pump 33 and stored in the water receiving tank 35 through the pipe 34.
The seawater stored in the water receiving tank 35 is desalinated by a desalinator (not shown).
[0004]
However, in the above water intake method, it is necessary to perform excavation work on the seabed in order to embed the water collecting perforated pipe 30 on the seabed, and there is a concern about adverse effects on fishing activities and marine ecosystems during construction. .
The above water intake method is suitable when the required water intake amount is relatively small, but is difficult to apply when a large amount of water intake is required, such as a large-scale seawater desalination plant. .
Therefore, it is conceivable to construct a tunnel under the seabed by a shield method or a propulsion method, but the tunnel should prevent the ingress of groundwater into the tunnel from the viewpoint of facility / equipment deterioration and drainage costs. Therefore, it is difficult to take groundwater directly from the tunnel.
[0005]
Here, the applicant previously filed a patent application for a tunnel lining member and a tunnel lining method that can directly and easily take groundwater from a tunnel constructed by a shield method or a propulsion method. (Japanese Patent Application No. 10-36363).
The tunnel lining member of this application is a tunnel lining member for lining a tunnel formed by excavating the underground,
A lining member body, and a water intake provided in the lining member body,
The intake section is configured to prevent inflow of earth and sand into the tunnel and to allow groundwater to flow into the tunnel. As a means for configuring the intake section in this way, for example, the intake section is A filter layer formed on the outer periphery of the lining member body to prevent inflow of earth and sand; and a ground layer formed on the lining member body inside the filter layer and passing through the filter layer. It is comprised from the intake hole made to flow in.
[0006]
In addition, the tunnel lining method is to construct a tunnel by excavating the tunnel with a shield machine and sequentially installing the tunnel lining member with the intake hole closed by an opening / closing member. And
After the tunnel construction is completed, the water intake hole is opened by the opening / closing member.
[0007]
Then, according to the tunnel lining member and the tunnel lining method as described above, the tunnel lining member is sequentially excavated with a shield machine, and the tunnel lining member is sequentially closed with the intake hole closed by the opening / closing member. By installing it, it is possible to prevent the inflow of groundwater during tunnel construction, and after completing the construction of the tunnel, by opening the intake hole by the opening and closing member, the groundwater can be taken into the tunnel and taken in, Therefore, a large amount of water can be easily taken.
[0008]
[Problems to be solved by the invention]
By the way, in the tunnel lining method as described above, since a gap is inevitably generated between the tunnel lining member such as a segment and the inner wall of the tunnel, a backfilling injection material such as concrete or mortar is injected into this gap. In this way, the soil is prevented from slackening after completion of the lining, and the earth pressure is uniformly transmitted to the lining member.
On the other hand, in the tunnel lining method as described above, since groundwater is allowed to flow into the constructed tunnel, the backfilling injection material is a material with low water permeability such as general concrete or mortar, There is a problem that groundwater is likely to be blocked by the backfilling injection material, making it difficult to take in a large amount of groundwater into the tunnel.
[0009]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a water-permeable backfilling injection material and a tunnel lining method capable of easily taking groundwater into a tunnel.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a water-permeable backfilling injection material according to the present invention is a backfilling injection material injected between a tunnel inner wall and a lining portion formed by lining the inside of the tunnel inner wall. Thus, a lightweight aggregate, a thickener and water are kneaded, and the water permeability coefficient is 1 × 10 ⁻¹ cm / sec to 5 × 10 ⁰ cm / sec.
[0011]
The hydraulic conductivity was set to 1 × 10 ⁻¹ cm / sec to 5 × 10 ⁰ cm / sec.
If it is less than 1 × 10 ^-1 cm / sec, the water permeability of the water-permeable backfilling injection material is poor, and it becomes difficult for the groundwater to penetrate.
Also, 5 if × exceeds 10 ⁰ cm / sec, although water permeability is improved, while the flow rate is increased, it is easy to move the soil particles of the natural ground, clogging the permeable back-filling grout It is for producing.
[0012]
As the lightweight aggregate, for example, foamed glass beads are preferably used. This foamed glass bead is a completely inorganic sintered body mainly composed of glass, and is a hanicoum structure containing countless closed cells, and has the following physical characteristics.
Particle size: 1.25 to 5.0 (mm), unit volume mass: 0.26 to 0.42 (kg / l),
Point load strength: 3-7 (kgf), water absorption: 5-10 (24h%),
Thermal conductivity: 0.086 (kcal / mh ℃)
[0013]
For example, guar gum is suitably used as the thickener, and the composition of this guar gum is as follows.
[Chemical 1]

[0014]
In the case where the light-weight aggregate, the thickener and water are kneaded, for example, the combination of light-weight aggregate per 1 m ³ : 250 kg, thickener: 5 kg, water: 495 kg,
Kneading with a mixer or the like for a predetermined time.
[0015]
In this water-permeable backfilling injection material, it is filled between the tunnel inner wall and the lining part, so that it has sufficient water permeability on the back side of the lining part and is clogged. A backfill layer is formed that is unlikely to occur. And since the said lining part shall have water permeability, groundwater will be easily taken in in a tunnel through the said backfill layer and a lining part. Moreover, even if the specific gravity of the lightweight aggregate constituting the water-permeable backfilling injection material is less than 1, the lightweight aggregate is uniformly dispersed by the thickener, and by pumping, It is uniformly and reliably injected and filled between the lining parts.
[0016]
Further, the water-permeable backfilling injection material of the present invention is a backfilling injection material injected between a tunnel inner wall and a lining portion formed by lining the inside of the tunnel inner wall, and a lightweight aggregate, Cement and water are kneaded, and the water permeability is 1 × 10 ⁻¹ cm / sec to 5 × 10 ⁰ cm / sec.
[0017]
Wherein the water permeability coefficient was ^{1 × 10 -1 cm / sec~5 ×} 10 0 cm / sec is due to the same reason as the case of the, is less than 1 × 10 ^-1 cm / sec, water permeability backing This is because the water permeability of the filling material is poor and it becomes difficult for the groundwater to permeate, and if it exceeds 5 × 10 ⁰ cm / sec, the water permeability improves, but on the other hand, the flow velocity increases, This is because the soil particles easily move and clog the water-permeable backfilling injection material.
[0018]
As the lightweight aggregate, foamed glass beads are preferably used as in the case described above . In the case of kneading the lightweight aggregate, cement and water, for example, the composition is as follows: lightweight aggregate per m ³ : 239 kg, cement: 68 kg, water: 490 kg, and mixed for a predetermined time by a mixer or the like. Knead. In addition, when kneading | mixing a lightweight aggregate, cement, and water, you may add a thickener as needed. The thickener is added in an amount of about 5 kg when light aggregate, cement and water are blended in the above ratio.
[0019]
In this water-permeable backfilling injection material, it is filled between the tunnel inner wall and the lining part, so that it has sufficient water permeability on the back side of the lining part and is clogged. A backfill layer is formed that is unlikely to occur. And since the said lining part shall have water permeability, groundwater will be easily taken in in a tunnel through the said backfill layer and a lining part. In addition, since the permeable backfill injection material contains cement, the backfill layer formed by injecting and filling the permeable backfill injection material between the tunnel inner wall and the lining part solidifies. As a result, loosening of the natural ground after completion of the lining is more reliably prevented.
[0020]
The tunnel lining method of the present invention forms a lining part by installing a lining member provided with a filter layer having water permeability inside the tunnel inner wall formed by excavation of natural ground , A tunnel lining method for forming a backfill layer by injecting and filling a water-permeable backfill injection material between the lining portion and the tunnel inner wall ,
The water-permeable backfilling injection material is a mixture of lightweight aggregate, water, thickener or cement, and the water permeability coefficient of the water-permeable backfilling injection material is 1 × 10 ⁻¹ cm / sec to 5 × 10. ⁰ cm / sec ,
The hydraulic conductivity of the natural ground, the hydraulic conductivity of the backfilling layer, and the hydraulic conductivity of the filter layer are set such that the hydraulic conductivity of the natural ground <the hydraulic conductivity of the backfilling layer <the hydraulic conductivity of the filter layer. It is characterized by being.
[0021]
As the lining member having water permeability, for example, a lining member main body and a water intake portion provided on the lining member main body are provided, and the water intake portion is formed on the outer peripheral portion of the lining member main body. A filter layer for preventing the inflow of earth and sand, and a water intake hole formed in the lining member body inside the filter layer and allowing groundwater that has passed through the filter layer to flow into the tunnel. Preferably used.
[0022]
In the tunnel lining method of the present invention, by installing a permeable covering member inside the excavated tunnel inner wall, a lining portion capable of taking groundwater is formed inside, and further, Injecting and filling the water-permeable backfilling injecting material between the lining portion and the inner wall of the tunnel has sufficient water permeability on the back side of the lining portion, and clogging occurs. A difficult backfill layer is formed. Therefore, groundwater is easily taken into the tunnel through the backfill layer and the lining portion.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.
First, before explaining the water-permeable backfilling injection material according to the present invention, a lining portion formed by lining the inside of the tunnel inner wall will be described.
FIG. 1 is a perspective view showing a tunnel lining portion F constructed by a shield method, and reference numerals 1 and 2 denote tunnel lining members. The tunnel lining members 1 and 2 each have an arc plate shape and are each formed of reinforced concrete.
[0024]
The four tunnel lining members 1 are joined in the circumferential direction to form a ring-opening ring, and the tunnel lining member 2 is fitted into the open portion of the ring-opening ring, so that one ring is formed. The body 3 is formed. And the said lining part F is formed by joining this ring body 3 ... in the axial direction of a tunnel.
[0025]
The tunnel lining member 1 includes a lining member main body 4 having a circular arc plate shape, and a water intake portion 5 provided on the lining member main body 4.
The lining member main body 4 is a segment 4 used in the shield method, and the segments 4, 4 adjacent to each other in the circumferential direction are joined together by a segment joint 4a as shown in FIGS. The segments adjacent in the axial direction are joined by the ring joint 4b.
[0026]
The water intake portion 5 prevents inflow of earth and sand into the tunnel and allows groundwater to flow into the tunnel. A filter layer is formed on the outer periphery of the segment 4 to prevent inflow of earth and sand. 6 and intake holes 7 that are formed in the segment 4 inside the filter layer 6 and allow groundwater that has passed through the filter layer 6 to flow into the tunnel.
[0027]
As shown in FIG. 6, the filter layer 6 is provided at the center of the segment 4, and the end of the segment 4 is made of concrete. By doing in this way, it can prevent that the filter layer 6 is damaged at the time of conveyance of a segment 4, and an assembly.
The filter layers 6 and 6 between the segments 4 and 4 adjacent to each other are communicated by a filter layer communication pipe 8 as shown in FIG. 4 and FIG. Groundwater can be distributed.
[0028]
The filter layer 6 has water permeability. As shown in FIG. 3, the filter layer 6 includes a first filter layer 6a disposed outside and a second filter layer 6b disposed inside the first filter layer 6a. It is configured. The permeability coefficient of the first filter layer 6a is set to about 10 to 100 times the permeability coefficient of the natural ground, which can prevent the earth soil particles from moving. The clogging of 6a can be prevented. Further, the water permeability coefficient of the second filter layer 6b is set higher than the water permeability coefficient of the first filter layer 6a, which makes it easy to collect water in the water intake hole 7.
[0029]
Further, as shown in FIGS. 5 and 6, a grout hole 4 c is formed in a substantially central portion of the segment 4. The grout hole 4c is a hole for injecting the water-permeable backfilling injection material according to the present invention between the segment 4 and the ground, and is formed through the segment 4 and the filter layer 6. .
A grout cap (not shown) is attached to the grout hole 4c, and the grout cap is removed when the water-permeable backfilling injection material is injected.
[0030]
The water-permeable backfilling injection material is obtained by kneading a lightweight aggregate, a thickener, and water, and its water permeability coefficient is set to about 8 × 10 ⁻¹ cm / sec. And it improves to about 2 × 10 ⁰ cm / sec due to the elution of the thickener after the injection by groundwater around the natural ground.
Specifically, the lightweight aggregate is a foam glass bead. This foamed glass bead is a completely inorganic sintered body containing glass as a main component, and has a hanicoum structure containing an infinite number of closed cells.
The thickener is specifically guar gum.
[0031]
In the case where the light-weight aggregate, the thickener and water are kneaded, for example, the combination of light-weight aggregate per 1 m ³ : 250 kg, thickener: 5 kg, water: 495 kg,
Kneading with a mixer or the like for a predetermined time.
The water-permeable backfill injection material kneaded in this way has a light-weight aggregate (foamed glass beads) with a specific gravity of less than 1, but is uniformly dispersed by the thickener (guar gum). Become.
[0032]
And the permeability coefficient of the natural ground, the permeability coefficient of the backfill layer formed by injecting the water-permeable backfill injection material, and the permeability coefficient of the filter layer are:
The permeability of the natural ground is set to be less than the permeability of the backfill layer <the permeability of the filter layer. The difference in the permeability is limited to about 100 times so as not to cause movement of soil particles. It has been.
By setting the difference between the respective water permeability coefficients in this way, it is possible to prevent the soil particles in the natural ground from moving, so that the backfill layer and the filter layer can be prevented from being clogged.
[0033]
As shown in FIGS. 1 to 6, three water intake holes 7 are formed in one segment 4, and each water intake hole 7 has a stop cock 10 that can open and close the water intake hole 7. It is detachably attached. And this stop cock 10 is made to flow in a groundwater in a tunnel by removing after completion of construction of a tunnel.
[0034]
As shown in FIG. 2, the tunnel lining member 2 is provided on the lining member main body (segment) 14 having a circular arc plate shape and the lining member main body 14 in the same manner as the tunnel lining member 1. As shown in FIG. 4, the segments 4 adjacent to each other in the axial direction are joined to the segments 4 adjacent to each other in the circumferential direction. It joins with the ring joint 4b.
[0035]
In addition, the water intake unit 15 includes a filter layer 16 and a water intake hole 17. Similarly to the filter layer 6, the filter layer 16 is composed of a first filter layer 16a and a second filter layer 16b, and the water permeability coefficient is set equal to that of the first filter layer 6a and the second filter layer 6b. Has been. Further, one water intake hole 17 is formed at the center of the segment 14, and the water stop cock 10 is detachably attached to the water intake hole 17. Further, the filter layer 16 of the tunnel lining member 2 and the filter layers 6 and 6 of the tunnel lining members 1 and 1 adjacent to the tunnel lining member 2 in the circumferential direction are respectively communicated by a filter layer communication pipe 8. ing.
[0036]
Next, a method for constructing a tunnel by a shield construction method using the tunnel lining members 1 and 2 and the water-permeable backfilling injection material having the above-described configuration will be described.
As shown in FIG. 7, a shaft 20 is constructed on the ground, and the shaft 20 is propelled while excavating the ground (ground) under the seabed by a shield machine 21. The excavation of the ground is performed by the cutter device 21 a at the tip of the shield machine 21. In the shield machine 21, the segment 22 that is a cylindrical divided body is assembled in the circumferential direction of the drill hole, and the reaction force is applied to the front end of the segment 22. The shield machine 21 is propelled by extending the propulsion jack in the shield machine. Further, between the segment 22 and the ground, the backfilling material 23 is injected from the grout hole formed in the segment 22. As the back-filling material 23, a mortar material is used.
[0037]
Then, if the shield machine 21 is dug to a predetermined position while excavating and propelling by the shield machine 21, assembling the segments 22, and injecting the backfill material 23, the tunnel lining members 1 and 2 are moved in the circumferential direction. By assembling and joining, a ring body is formed, a reaction force is applied to the ring body, the shield machine 21 is dug, and the next tunnel lining members 1 and 2 are wound around the tip surface side of the ring body. Assemble and join in the direction to form the next ring body, and at the same time join this ring body to the already assembled ring body. When the tunnel lining members 1 and 2 are assembled, the stop cocks 10 are respectively attached to the water intake holes 7 and 17 formed in the tunnel lining members 1 and 2.
[0038]
Then, by repeating such a process a predetermined number of times, the tunnel lining members 1 and 2 cover the excavation hole into a cylindrical shape, and when the length of the cylindrical body reaches a predetermined length, the cylinder The bag-attached segment 26 is assembled and joined in the circumferential direction on the distal end side of the body. The bag-attached segment 26 is provided with a shielding bag on the back side of the same segment as the segment 22, and the shielding bag is in close contact with the inner wall of the excavation hole.
The segment 26 with bag is also installed between the segment 22 and the tunnel lining members 1 and 2.
And if the said segment 26 with a bag is assembled, the water-permeable backfilling injection material 25 which concerns on this invention mentioned above from the grout hole each formed in the said tunnel lining members 1 and 2 will be inject | poured, and a ground and a tunnel Fill the space between the lining members 1 and 2. The water permeable backfilling injection material 25 is injected by connecting a hose (not shown) to the grout hole and pumping the hose through the hose.
[0039]
Further, in the same manner as described above, the excavation is carried out by the shield machine 21 and the excavation hole is covered in a cylindrical shape by the tunnel lining members 1 and 2, and when the length of the cylinder reaches a predetermined length, The process of assembling the bag-attached segment 26, injecting the water-permeable backfilling injection material 25 from the grout hole of the tunnel lining members 1 and 2, and filling between the ground and the tunnel lining members 1 and 2 in sequence By repeating the process a predetermined number of times, the tunnel will be constructed in the ground.
And after completion of the construction of the tunnel, the water intake holes 7 and 17 are opened by removing the stop cocks 10 attached to the water intake holes 7 and 17 of the tunnel lining members 1 and 2.
[0040]
When the intake holes 7 and 17 are opened, the groundwater (seawater) passes through the backfill layer 27 and the filter layers 6 and 16 formed by injecting and filling the permeable backfill injection material 25, and the intake holes 7 and 17. 17 flows into the tunnel and is stored in the storage tank 20a formed in the shaft 20, and the stored seawater is sucked up by the submersible pump 28 and stored in the water receiving tank 29 through the pipe 29a. Then, if the groundwater continues to flow into the tunnel for a predetermined time, the thickener of the water-permeable backfilling injection material 25 is eluted, thereby further increasing the water permeability.
As described above, the tunnel covered by the lining members 1 and 2 and the water-permeable backfilling injection material 25 of this example has both functions of a water collecting perforated pipe and a water conduit, and therefore requires a large amount of water intake. It is suitable for the case.
[0041]
Further, the water intake portions 5 and 15 provided in the lining members 1 and 2 are provided with filter layers 6 and 16 for preventing inflow of earth and sand, and water intake for allowing seawater that has passed through the filter layers 6 and 16 to flow into the tunnel. Since it comprised from the holes 7 and 17, the inflow of the earth and sand into a tunnel can be prevented, and only seawater can be taken in reliably.
[0042]
Furthermore, since the stop cock 10 is detachably attached to the water intake holes 7 and 17, it is possible to prevent inflow of seawater during tunnel construction by attaching the stop cock 10 during construction of the tunnel. After the construction of the tunnel is completed, seawater can be taken into the tunnel to be taken in by removing the stop cock 10 and opening the intake holes 7 and 17.
[0043]
In the above example, the case where the present invention is applied to the shield method has been described as an example. However, the present invention is not limited to this and can also be applied to the propulsion method.
In this case, the propelling pipe is provided with a water intake portion composed of a filter layer and a water intake hole in the same manner as described above, and a water-permeable backfilling injection material is injected between the propelling pipe and the ground. do it.
[0044]
In the above example, as the water-permeable backfilling injection material, a lightweight aggregate (foamed glass beads), a thickener (guar gum) and water were used, but instead of this, A material obtained by kneading lightweight aggregate (foamed glass beads), cement and water may be used. In this case, the backfill layer formed by injecting and filling the aqueous backfilling injection material between the tunnel inner wall and the lining part solidifies, so that loosening of the natural ground after the lining is completed is more reliably prevented. be able to.
[0045]
【The invention's effect】
As described above, according to the water-permeable backfilling injection material of the present invention , a lightweight aggregate, a thickener and water are kneaded, and the water permeability coefficient is 1 × 10 ⁻¹ cm / sec to 5 ×. 10 ⁰ since the cm / sec, comprising: a translucent aqueous back-filling grout tunnel inner wall, by injecting to fill between the lining portion, sufficient permeability to the rear side of the lining part In addition, it is possible to form a backfill layer that is less likely to be clogged. Therefore, groundwater can be easily taken into the tunnel through the backfill layer and the lining portion by providing the lining portion with water permeability. Moreover, even if the specific gravity of the lightweight aggregate constituting the water-permeable backfilling injection material is less than 1, the lightweight aggregate can be uniformly dispersed by the thickener, and by pumping, It is possible to uniformly and reliably inject and fill between the tunnel inner wall and the lining portion.
[0046]
Moreover, according to the water permeable backfilling injection material according to the present invention , a lightweight aggregate, cement and water are kneaded, and the water permeability coefficient is 1 × 10 ⁻¹ cm / sec to 5 × 10 ⁰ cm / sec. Therefore, by filling the water permeable backfilling injection material between the tunnel inner wall and the lining part, it has sufficient water permeability on the back side of the lining part and is clogged. It is possible to form a backfill layer that is unlikely to occur. Therefore, groundwater can be easily taken into the tunnel through the backfill layer and the lining portion by providing the lining portion with water permeability. In addition, since the permeable backfill injection material contains cement, the backfill layer formed by injecting and filling the permeable backfill injection material between the tunnel inner wall and the lining part solidifies. As a result, it is possible to more reliably prevent the loosening of the ground after completion of the lining.
[0047]
According to the tunnel lining method of the present invention, by installing a permeable covering member inside the tunnel inner wall that has been excavated, it is possible to easily provide a lining portion capable of taking groundwater inside. In addition, the water-permeable backfilling injection material according to claim 1 or 2 is injected and filled between the lining portion and the inner wall of the tunnel, so that the back side of the lining portion is sufficient. Therefore, it is possible to easily form a backfill layer that has excellent water permeability and is less likely to be clogged. Therefore, groundwater can be easily taken into the tunnel through the backfill layer and the lining portion.
[Brief description of the drawings]
FIG. 1 is a perspective view conceptually showing a lining portion, showing an example of a lining portion constructed by a tunnel lining method of the present invention.
FIG. 2 is a sectional view conceptually showing the lining portion.
FIG. 3 is an enlarged view of the water intake section in FIG. 2;
FIG. 4 is a sectional view of the lining portion.
FIG. 5 is a side sectional view of the tunnel lining member.
FIG. 6 is a plan view of the tunnel lining member.
FIG. 7 is a side sectional view of the tunnel for explaining the tunnel lining method of the present invention.
FIG. 8 shows an example of a conventional water intake system, and is a side sectional view showing a water collecting perforated pipe and a long water conduit pipe installed under the seabed.
[Explanation of symbols]
F Covering part 1, 2 Tunnel lining member 4, 14 Covering member body (segment)
5,15 Intake section 6,16 Filter layer 7,17 Intake hole 10 Water stop cock (opening / closing member)
25 Permeable backfill injection material 27 Backfill layer

Claims (3)

Inside the forming tunnel inner wall by excavating a natural ground, to form the lining part by local and regional building lining member provided with a filter layer having a water permeability, between said cover coated portion and the tunnel inner wall A tunnel lining method in which a permeable backfill injection material is injected and filled to form a backfill layer.
The water-permeable backfilling injection material is a mixture of lightweight aggregate, water, thickener or cement, and the water permeability coefficient of the water-permeable backfilling injection material is 1 × 10 ⁻¹ cm / sec to 5 × 10. ⁰ cm / sec ,
The hydraulic conductivity of the natural ground, the hydraulic conductivity of the backfilling layer, and the hydraulic conductivity of the filter layer are set such that the hydraulic conductivity of the natural ground <the hydraulic conductivity of the backfilling layer <the hydraulic conductivity of the filter layer. Tunnel lining method characterized by being made . The lining member includes a lining member main body and a water intake portion provided on the lining member main body, and the water intake portion is formed on an outer peripheral portion of the lining member main body to prevent inflow of earth and sand. The filter layer according to claim 1, and a water intake hole that is formed in the lining member body inside the filter layer and allows groundwater that has passed through the filter layer to flow into the tunnel. The tunnel lining method described. The filter layer includes a first filter layer disposed on the outside and a second filter layer disposed on the inside of the first filter layer, and the permeability coefficient of the first filter layer is the permeability of the natural mountain. 2. The tunnel covering according to claim 1, wherein the coefficient is set to about 10 to 100 times the coefficient, and the water permeability coefficient of the second filter layer is set higher than the water permeability coefficient of the first filter layer. Construction method.

Images