JP2022148185A

JP2022148185A - Steel support

Info

Publication number: JP2022148185A
Application number: JP2021049768A
Authority: JP
Inventors: 奈央池田; Nao Ikeda; 秀幸村山; Hideyuki Murayama; 勝識平野; Katsunori Hirano
Original assignee: Fujita Corp
Current assignee: Fujita Corp
Priority date: 2021-03-24
Filing date: 2021-03-24
Publication date: 2022-10-06

Abstract

To provide a steel support that can tolerate a deformation to some extent without largely protruding to inside of a tunnel when pressure is applied to circumference of an excavation surface from foundation and allows lining work to be smoothly executed.SOLUTION: A steel support 16 supports an excavation surface 12 in collaboration with a spraying concrete 14 sprayed on the excavation surface 12 and a plurality of rock bolts 18 driven in the excavation surface 12 from a surface of the spraying concrete 14. The steel support 16 includes a support 20 configured by connecting a plurality of steel support members 22. A steel deformation induction member 26A that more easily deforms than the steel support member 22 is disposed at a plurality of positions at intervals in extending direction of the support 20.SELECTED DRAWING: Figure 2

Description

本発明はＮＡＴＭの支保に用いられる鋼製支保工に関する。 The present invention relates to steel shoring used in NATM shoring.

ＮＡＴＭで掘削されるトンネルでは、爆破や掘削装置で地山に掘削したトンネルの掘削表面に一次吹き付けとしてコンクリートを吹き付け、このコンクリートに沿わせて鋼製支保工を組み立て、コンクリートと鋼製支保工に二次吹き付けとしてコンクリートを吹き付け、さらに、コンクリートの上から複数のロックボルトを地山に打ち込む支保がなされる。
そして、鋼製支保工と、吹き付けコンクリートと、ロックボルトとにより掘削表面の崩落を防止しつつ掘削表面を支えるようにしている。
なお、地山の地質によっては、鋼製支保工とロックボルトのうち何れか一方が省略される場合もある。
その後、掘削表面の周囲の地山が安定したならば、鋼製支保工、吹き付けコンクリート、ロックボルトの上からスライドセントルを利用してコンクリートを打設する覆工がなされる。
このようにＮＡＴＭでは、鋼製支保工と、吹き付けコンクリートと、ロックボルトとにより掘削表面の崩落を防止しつつ掘削表面を支え、掘削表面の周囲の地山を安定化させるため、覆工のコンクリートの厚さを小さくできるという利点を有している。
一方、ＮＡＴＭでは、掘削表面に周囲の地山からの圧力が作用した場合、掘削表面の周囲の地山を安定化させるため、鋼製支保工にはある程度の変形を許容し、地山の変形を吸収することが望ましい。
このような観点から、鋼製支保工を構成する鋼製支保部材に変形を許容させる技術が開示されている（特許文献１）。 In tunnels excavated by NATM, concrete is sprayed as a primary spray onto the excavated surface of the tunnel excavated in the ground by blasting or excavating equipment, and steel shoring is assembled along this concrete, and the concrete and steel shoring are combined. Concrete is sprayed as a secondary spray, and support is provided by driving a plurality of rock bolts into the ground from above the concrete.
The steel shoring, the shotcrete, and the rock bolts prevent the excavated surface from collapsing and support the excavated surface.
Either one of the steel shoring and rock bolts may be omitted depending on the geology of the natural ground.
After that, when the ground around the excavation surface stabilizes, lining is done by pouring concrete over steel shoring, shotcrete, and rock bolts using a slide center.
In this way, in NATM, steel shoring, shotcrete, and rock bolts are used to prevent the excavated surface from collapsing and to support the excavated surface. has the advantage of being able to reduce the thickness of
On the other hand, in NATM, when pressure from the surrounding ground acts on the excavated surface, in order to stabilize the ground around the excavated surface, the steel shoring is allowed to deform to some extent. should be absorbed.
From such a point of view, a technique for allowing deformation of steel support members constituting a steel support has been disclosed (Patent Document 1).

特許第６５８４７３８号公報Japanese Patent No. 6584738

しかしながら、上述の従来技術では、合成樹脂製の骨組み構造体にコンクリートを吹き付けたコンクリート体を用いるため、地山からの圧力が掘削表面の周囲に作用した際、コンクリートが圧縮されてトンネルの内側に大きく突出し、覆工工事を円滑に行なえず、覆工工事に支障をきたす不具合があった。
本発明はこのような事情に鑑みなされたものであり、その目的は、掘削表面の周囲に地盤からの圧力が作用した際、トンネルの内側に大きく突出することなく支保工にある程度の変形を許容させることができ、上述の従来技術に比べて覆工工事を円滑に行なえ、トンネル工事の施工期間を短縮し、コストダウンを図る上で有利な鋼製支保工を提供することにある。 However, in the conventional technology described above, since a concrete body formed by spraying concrete onto a frame structure made of synthetic resin is used, when pressure from the natural ground acts on the periphery of the excavation surface, the concrete is compressed and pushed inside the tunnel. There was a problem that the lining work could not be carried out smoothly due to the protruding part, which hindered the lining work.
The present invention has been made in view of such circumstances, and its object is to allow the shoring to deform to some extent without protruding significantly inside the tunnel when pressure from the ground acts around the excavated surface. To provide a steel shoring which is capable of performing lining work more smoothly than the above-mentioned prior art, shortens the construction period of tunnel work, and is advantageous in reducing costs.

上述の目的を達成するため、本発明の一実施の形態は、掘削されたトンネルの掘削表面に吹き付けられた吹き付けコンクリートと協働して前記掘削表面を支える、前記掘削表面に沿わせて組み立てられた鋼製支保工であって、前記鋼製支保工は、前記トンネルの掘削方向と直交する平面内で前記掘削表面に沿って延在する複数の鋼製支保部材が連結されて構成された支保工を含んで構成され、前記支保工の延在方向に間隔をおいた複数箇所に、前記鋼製支保部材よりも変形し易い鋼製変形誘発部材が配置されていることを特徴とする。
また、本発明の一実施の形態は、前記鋼製変形誘発部材の前記支保工の延在方向に沿った長さや断面形状あるいは断面係数あるいは前記鋼製変形誘発部材を構成する材料は、地山からの荷重が前記掘削表面から前記支保工に作用した際の前記鋼製変形誘発部材の変形量を考慮して設定されていることを特徴とする。
また、本発明の一実施の形態は、前記鋼製支保部材と前記鋼製変形誘発部材は同一の形鋼で構成され、前記鋼製支保部材と前記鋼製変形誘発部材とは、前記トンネルの掘削方向に対して前記形鋼の断面形状の向きを変えて配置されていることを特徴とする。
また、本発明の一実施の形態は、前記鋼製支保部材と前記鋼製変形誘発部材とは、共に一対のフランジとそれらフランジを連結するウェブとからなる同一のＨ形鋼で構成され、前記鋼製支保部材を構成する前記Ｈ形鋼は前記ウェブを前記トンネルの掘削方向に対向させて配置され、前記鋼製変形誘発部材を構成する前記Ｈ形鋼は前記ウェブを前記トンネル断面の中央に対向させて配置されていることを特徴とする。
また、本発明の一実施の形態は、前記鋼製支保部材と前記鋼製変形誘発部材は、互いに形状が異なる形鋼で構成されていることを特徴とする。
また、本発明の一実施の形態は、前記鋼製支保部材は、一対のフランジとそれらフランジを連結するウェブとからなるＨ形鋼で構成され、前記Ｈ形鋼は、前記ウェブを前記トンネルの掘削方向に対向させて配置され、前記鋼製変形誘発部材は、ウェブと、前記ウェブの両端から起立する一対のフランジとからなる溝型鋼で構成され、前記溝型鋼は、前記ウェブを前記トンネル断面の中央に対向させて配置されていることを特徴とする。
また、本発明の一実施の形態は、前記鋼製支保部材は形鋼で構成され、前記鋼製変形誘発部材は鉄筋で構成されていることを特徴とする。
また、本発明の一実施の形態は、前記鋼製変形誘発部材の断面係数は、前記鋼製支保部材の断面係数よりも小さいことを特徴とする。
また、本発明の一実施の形態は、前記鋼製変形誘発部材は、前記鋼製支保部材よりも変形し易い材料で形成されていることを特徴とする。
また、本発明の一実施の形態は、前記鋼製支保部材と前記鋼製変形誘発部材とは連結部材を介して連結されていることを特徴とする。 To achieve the above objectives, one embodiment of the present invention provides an excavation surface of an excavated tunnel which supports said excavation surface in cooperation with shotcrete sprayed onto said excavation surface. The steel shoring is constructed by connecting a plurality of steel shoring members extending along the excavation surface in a plane perpendicular to the excavation direction of the tunnel. It is characterized in that steel deformation inducing members, which are more deformable than the steel support members, are arranged at a plurality of locations spaced apart in the extending direction of the support.
Further, in one embodiment of the present invention, the length, cross-sectional shape, or section modulus of the steel deformation inducing member along the extending direction of the shoring, or the material constituting the steel deformation inducing member is is set in consideration of the amount of deformation of the steel deformation inducing member when a load from the excavation surface acts on the shoring.
Further, in one embodiment of the present invention, the steel supporting member and the steel deformation inducing member are made of the same shaped steel, and the steel supporting member and the steel deformation inducing member are formed from the tunnel. It is characterized in that the cross-sectional shape of the shaped steel is arranged in a different direction with respect to the excavation direction.
In one embodiment of the present invention, the steel supporting member and the steel deformation inducing member are both made of the same H-section steel comprising a pair of flanges and a web connecting the flanges, and The H-section steel constituting the steel support member is arranged so that the web faces the direction of excavation of the tunnel, and the H-section steel constituting the steel deformation inducing member has the web at the center of the cross section of the tunnel. It is characterized by being arranged to face each other.
Moreover, one embodiment of the present invention is characterized in that the steel supporting member and the steel deformation inducing member are formed of shaped steels having different shapes.
Also, in one embodiment of the present invention, the steel support member is composed of an H-section steel having a pair of flanges and a web connecting the flanges, and the H-section steel connects the web to the tunnel. The steel deformation inducing members are arranged opposite to each other in the excavation direction, and are composed of channel steel comprising a web and a pair of flanges standing from both ends of the web, the channel steel connecting the web to the tunnel cross section. characterized in that they are arranged facing the center of the
Moreover, one embodiment of the present invention is characterized in that the steel supporting members are formed of shaped steel, and the steel deformation inducing members are formed of reinforcing bars.
Moreover, one embodiment of the present invention is characterized in that the section modulus of the steel deformation inducing member is smaller than the section modulus of the steel support member.
Moreover, one embodiment of the present invention is characterized in that the steel deformation inducing member is made of a material that deforms more easily than the steel supporting member.
Moreover, one embodiment of the present invention is characterized in that the steel supporting member and the steel deformation inducing member are connected via a connecting member.

本発明の一実施の形態によれば、掘削表面にトンネルの周囲の地山からの荷重が作用した際、鋼製支保部材よりも率先して鋼製変形誘発部材が変形することで地山の変形を吸収し、トンネルの周囲の地山を安定化することができる。
この場合、鋼製変形誘発部材は鋼製の部材であり変形量を調整できることから、従来のように、トンネルの内側に大きく突出することもない。
したがって、掘削表面に周囲の地山からの荷重が作用した場合、鋼製支保工にある程度の変形を許容させて地山を安定させることができ、上述の従来技術のようにトンネルの内側に大きく突出することもないので、上述の従来技術に比べて覆工工事を円滑に行なえ、トンネル工事の施工期間を短縮し、コストダウンを図る上で有利となる。
鋼製変形誘発部材の変形量は、その長さや断面形状、断面係数、材料を適宜設定することで調整可能である。
また、鋼製支保部材と鋼製変形誘発部材とに同一の形鋼を用いても、トンネルの掘削方向に対して形鋼の断面形状の向きを変えて使用できるため、コストダウンを図る上で有利となる。
また、鋼製変形誘発部材として、鋼製支保部材を構成するＨ形鋼を使用すると、鋼製支保部材の製作時に、鋼製変形誘発部材を一緒に製作でき、上述の従来技術に比べてトンネル工事の施工期間を短縮し、コストダウンを図る上で有利となる。
また、鋼製支保部材と鋼製変形誘発部材とを互いに形状が異なる形鋼で構成すると、市販品を使用できることから簡単に入手できて鋼製支保部材と鋼製変形誘発部材とを簡単に製作でき、上述の従来技術に比べてトンネル工事の施工期間を短縮し、コストダウンを図る上で有利となる。
また、鋼製支保部材と鋼製変形誘発部材とを互いに形状が異なる形鋼で構成する場合、鋼製支保部材としてＨ形鋼を用い、鋼製変形誘発部材として溝型鋼を用いると、それらは簡単に入手できることから、鋼製支保部材と鋼製変形誘発部材とを簡単に製作する上で有利となる。
また、鋼製支保部材として形鋼を用い、鋼製変形誘発部材として鉄筋を用いると、それらは簡単に入手できることから、鋼製支保部材と鋼製変形誘発部材とを簡単に製作する上で有利となる。
また、鋼製変形誘発部材は、鋼製支保部材の断面係数よりも小さい鋼製の部材を用いることで、あるいは、鋼製支保部材よりも変形し易い材料を用いることで簡単に製作する上で有利となる。
また、鋼製支保部材と鋼製変形誘発部材とは連結部材を用いて連結でき、連結部材としては、プレートやブラケットなど簡単な構成のものを使用して確実に連結できる。 According to one embodiment of the present invention, when a load from the natural ground around the tunnel acts on the excavation surface, the steel deformation-inducing member deforms more than the steel supporting member, thereby causing the natural ground to be deformed. It can absorb deformation and stabilize the ground surrounding the tunnel.
In this case, the steel deformation inducing member is a member made of steel and the amount of deformation can be adjusted.
Therefore, when a load is applied to the excavation surface from the surrounding natural ground, the steel shoring can be allowed to deform to some extent to stabilize the natural ground. Since it does not protrude, the lining work can be performed more smoothly than in the above-described conventional technology, which is advantageous in terms of shortening the construction period for tunnel construction and reducing costs.
The amount of deformation of the steel deformation inducing member can be adjusted by appropriately setting its length, cross-sectional shape, section modulus, and material.
In addition, even if the same shaped steel is used for the steel supporting member and the steel deformation inducing member, the cross-sectional shape of the shaped steel can be changed in direction with respect to the tunnel excavation direction. be advantageous.
In addition, if the H-shaped steel constituting the steel supporting member is used as the steel deformation inducing member, the steel deformation inducing member can be manufactured together with the steel supporting member. This is advantageous in terms of shortening the construction period and reducing costs.
In addition, if the steel supporting member and the steel deformation inducing member are composed of shaped steels having different shapes, the steel supporting member and the steel deformation inducing member can be easily manufactured because commercially available products can be used. This is advantageous in terms of shortening the construction period for tunnel construction and reducing costs compared to the above-described prior art.
Further, when the steel supporting member and the steel deformation inducing member are formed of shaped steels having different shapes, if H-shaped steel is used as the steel supporting member and channel steel is used as the steel deformation inducing member, Since it is easily available, it is advantageous in easily manufacturing the steel supporting member and the steel deformation inducing member.
In addition, if shaped steel is used as the steel supporting member and reinforcing bars are used as the steel deformation inducing member, they are easily available, which is advantageous in easily manufacturing the steel supporting member and the steel deformation inducing member. becomes.
In addition, the steel deformation inducing member can be easily manufactured by using a steel member having a section modulus smaller than that of the steel supporting member, or by using a material that deforms more easily than the steel supporting member. be advantageous.
Further, the steel supporting member and the steel deformation inducing member can be connected using a connecting member, and the connecting member can be reliably connected by using a simple structure such as a plate or a bracket.

掘削表面を支える鋼製支保工と、吹き付けコンクリートと、ロックボルトの説明図である。Fig. 2 is an illustration of steel shoring, shotcrete and rock bolts supporting the excavated surface; 鋼製支保工の正面図である。It is a front view of a steel shoring. （Ａ）は、掘削表面と、一次吹き付けのコンクリートと、第１の実施の形態の鋼製支保部材を構成するＨ形鋼の説明図、（Ｂ）は掘削表面と、一次吹き付けのコンクリートと、第１の実施の形態の鋼製変形誘発部材を構成するＨ形鋼の説明図である。(A) is an explanatory diagram of the excavated surface, the primary sprayed concrete, and the H-shaped steel that constitutes the steel support member of the first embodiment; (B) is the excavated surface, the primary sprayed concrete, It is explanatory drawing of H-shaped steel which comprises the steel deformation inducing member of 1st Embodiment. 第１の実施の形態の鋼製支保部材と鋼製変形誘発部材の位置関係の説明図である。FIG. 4 is an explanatory diagram of the positional relationship between the steel supporting member and the steel deformation inducing member of the first embodiment; （Ａ）はトンネルの掘削方向から第１の実施の形態の鋼製支保部材と鋼製変形誘発部材とがプレートで連結された状態を見た図、（Ｂ）は（Ａ）のＢＢ断面図である。(A) is a view of the state in which the steel supporting member and the steel deformation inducing member of the first embodiment are connected by a plate from the excavation direction of the tunnel, and (B) is a BB cross-sectional view of (A). is. 第１の実施の形態のプレートに代えてブラケットを用いて連結される鋼製支保部材と鋼製変形誘発部材の説明図で、（Ａ）はトンネル断面の中央から鋼製支保部材と鋼製変形誘発部材を見た図、（Ｂ）はトンネルの掘削方向から鋼製支保部材と鋼製変形誘発部材を見た図である。Explanatory drawing of a steel support member and a steel deformation inducing member that are connected using a bracket instead of the plate of the first embodiment, (A) is a steel support member and a steel deformation from the center of the tunnel cross section FIG. 2B is a view of the induction member, and FIG. 4B is a view of the steel support member and the steel deformation induction member from the excavation direction of the tunnel. （Ａ）はトンネル断面の中央から鋼製支保部材と鋼製変形誘発部材とがブラケットで連結された状態を見た断面図、（Ｂ）はトンネルの掘削方向から鋼製支保部材と鋼製変形誘発部材とがブラケットで連結された状態を見た図である。(A) is a cross-sectional view of the steel support member and the steel deformation inducing member connected by a bracket from the center of the tunnel cross section, and (B) is a steel support member and steel deformation from the tunnel excavation direction. It is the figure which looked at the induction member and the state connected with the bracket. （Ａ）はブラケットの断面側面図、（Ｂ）は同ブラケットの正面図である。(A) is a cross-sectional side view of a bracket, and (B) is a front view of the same bracket. 鋼製変形誘発部材と一次吹き付けのコンクリートとの間の隙間を閉塞する説明図である。FIG. 4 is an explanatory diagram of closing a gap between a steel deformation inducing member and primary sprayed concrete; 第２の実施の形態の鋼製支保部材と鋼製変形誘発部材の位置関係の説明図である。FIG. 10 is an explanatory diagram of the positional relationship between the steel supporting member and the steel deformation inducing member of the second embodiment; （Ａ）はトンネル断面の中央から第２の実施の形態の鋼製支保部材と鋼製変形誘発部材とがブラケットで連結された状態を見た断面図、（Ｂ）はトンネルの掘削方向から第２の実施の形態の鋼製支保部材と鋼製変形誘発部材とがブラケットで連結された状態を見た図である。(A) is a cross-sectional view of the state in which the steel support member and the steel deformation inducing member of the second embodiment are connected by a bracket from the center of the tunnel cross section, and (B) is a cross-sectional view from the tunnel excavation direction. Fig. 10 is a diagram showing a state in which the steel supporting member and the steel deformation inducing member of the second embodiment are connected with a bracket; （Ａ）は第２の実施の形態のブラケットの側面図、（Ｂ）は同ブラケットの正面図、（Ｃ）は底面図である。(A) is a side view of the bracket of 2nd Embodiment, (B) is a front view of the same bracket, (C) is a bottom view. 第３の実施の形態の鋼製支保部材と鋼製変形誘発部材の位置関係の説明図である。FIG. 10 is an explanatory diagram of the positional relationship between the steel supporting member and the steel deformation inducing member of the third embodiment; （Ａ）はトンネル断面の中央から第３の実施の形態の鋼製支保部材と鋼製変形誘発部材とがブラケットで連結された状態を見た断面図、（Ｂ）はトンネルの掘削方向から第３の実施の形態の鋼製支保部材と鋼製変形誘発部材とがブラケットで連結された状態を見た図である。(A) is a cross-sectional view of the state in which the steel supporting member and the steel deformation inducing member of the third embodiment are connected by a bracket from the center of the tunnel cross section, and (B) is a cross-sectional view from the tunnel excavation direction. FIG. 10 is a diagram showing a state in which a steel supporting member and a steel deformation inducing member of Embodiment 3 are connected with a bracket; （Ａ）は第３の実施の形態のブラケットの平面図、（Ｂ）は同ブラケットの一部断面正面図、（Ｃ）は側面図である。(A) is a plan view of a bracket of a third embodiment, (B) is a partially cross-sectional front view of the same bracket, and (C) is a side view.

（第１の実施の形態）
まず、本発明の第１の実施の形態について図１～図５を参照して説明する。
図１に示すように、切羽の近傍のトンネル１０の箇所では、爆破や掘削装置でトンネル１０が掘削され、このトンネル１０の掘削表面１２に一次吹き付けとしてコンクリート１４Ａが吹き付けられ、この一次吹き付けのコンクリート１４Ａの表面に沿わせて鋼製支保工１６がアーチ状に組み立てられる。
そして、一次吹き付けのコンクリート１４Ａに、鋼製支保工１６の表面付近まで二次吹き付けとしてコンクリート１４Ｂが吹き付けられ、さらに、二次吹き付けのコンクリート１４Ｂの上から複数のロックボルト１８がトンネル１０の周辺の地山に打ち込まれる。
ＮＡＴＭでは、このような鋼製支保工１６と、吹き付けコンクリート１４と、ロックボルト１８とにより掘削表面１２の崩落を防止しつつ掘削表面１２を支え、掘削表面１２の周囲の地山を安定化させるようにしている。
なお、地山の地質によっては、ロックボルト１８が省略される場合もあり、その場合にも本発明は無論適用される。
そして、掘削表面１２の周囲の地山が安定したならば、鋼製支保工１６、吹き付けコンクリート１４、ロックボルト１８の上からスライドセントルを利用してコンクリートを打設する覆工がなされる。 (First embodiment)
First, a first embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG.
As shown in FIG. 1, at the location of the tunnel 10 near the face, the tunnel 10 is excavated by blasting or excavation equipment, and the excavated surface 12 of the tunnel 10 is sprayed with concrete 14A as a primary spray. A steel shoring 16 is assembled in an arch along the surface of 14A.
Then, concrete 14B is sprayed on the primary sprayed concrete 14A to the vicinity of the surface of the steel shoring 16 as secondary spraying, and furthermore, a plurality of rock bolts 18 are installed around the tunnel 10 from above the secondary sprayed concrete 14B. driven into the ground.
In NATM, the steel shoring 16, the shotcrete 14, and the rock bolts 18 prevent the excavated surface 12 from collapsing, support the excavated surface 12, and stabilize the ground around the excavated surface 12. I'm trying
Note that the rock bolts 18 may be omitted depending on the geology of the natural ground, and the present invention is of course applicable in that case as well.
Then, when the ground surrounding the excavation surface 12 is stabilized, a lining is made by pouring concrete from above the steel shoring 16, the shotcrete 14, and the rock bolts 18 using a slide center.

鋼製支保工１６は、トンネル１０の掘削方向Ｘ（図３、図４参照）に間隔をおいて設けられた図２に示す複数の支保工２０を含んで構成されている。
支保工２０は、トンネル１０の掘削方向Ｘと直交する平面でトンネル１０を切断したトンネル断面の周方向に沿ってアーチ状に延在し、不図示のつなぎ材が、トンネル１０の掘削方向Ｘに延在し隣り合う支保工２０の複数箇所を連結している。 The steel shoring 16 includes a plurality of shorings 20 shown in FIG. 2 spaced apart in the excavation direction X of the tunnel 10 (see FIGS. 3 and 4).
The shoring 20 extends in an arch shape along the circumferential direction of the tunnel cross section obtained by cutting the tunnel 10 on a plane perpendicular to the excavation direction X of the tunnel 10, and a connecting material (not shown) extends in the excavation direction X of the tunnel 10. A plurality of portions of the extending and adjacent shorings 20 are connected.

図２に示すように、支保工２０は、複数の鋼製支保部材２２と、複数の鋼製変形誘発部材２６Ａとを含んで構成されている。
鋼製支保部材２２は形鋼で構成され、本実施の形態では、鋼製支保部材２２は、図３（Ａ）に示すように、一対のフランジ２４０２とそれらフランジ２４０２を接続するウェブ２４０４とからなるＨ形鋼で構成されている。
本実施の形態では、一対のフランジ２４０２の外面間の寸法と、フランジ２４０２の幅とが同一の値で設けられている。
鋼製支保部材２２を構成するＨ形鋼は、一対のフランジ２４０２を、トンネル１０の掘削方向Ｘと直交する平面でトンネル１０を切断したトンネル断面のほぼ中央に対向させ、ウェブ２４０４をトンネル１０の掘削方向Ｘに対向させて配置されている。 As shown in FIG. 2, the shoring 20 includes a plurality of steel supporting members 22 and a plurality of steel deformation inducing members 26A.
The steel support member 22 is made of shaped steel, and in this embodiment, the steel support member 22 consists of a pair of flanges 2402 and a web 2404 connecting the flanges 2402, as shown in FIG. It is made of H-shaped steel.
In this embodiment, the dimension between the outer surfaces of the pair of flanges 2402 and the width of the flanges 2402 are set to the same value.
The H-shaped steel that constitutes the steel support member 22 has a pair of flanges 2402 opposed to approximately the center of the tunnel cross section that cuts the tunnel 10 on a plane perpendicular to the excavation direction X of the tunnel 10, and the web 2404 of the tunnel 10. They are arranged opposite to each other in the excavation direction X.

鋼製変形誘発部材２６Ａは、図２に示すように、支保工２０の延在方向に間隔をおいた複数箇所に設けられている。
鋼製変形誘発部材２６Ａは、掘削表面１２からの地山の荷重が支保工２０に作用した際に、鋼製支保部材２２よりも率先して変形する鋼製の部材である。
支保工２０に設けられる複数の鋼製変形誘発部材２６Ａの長さの総和は、支保工２０の全長の１割程度であり、一つの鋼製変形誘発部材２６Ａの長さは、支保工２０の全長の数パーセント程度である。
本実施の形態では、鋼製変形誘発部材２６Ａは、鋼製支保部材２２を構成するＨ形鋼と同一のＨ形鋼で構成され、詳細には、その断面形状が鋼製支保部材２２を構成するＨ形鋼と同一形状、同一の大きさのＨ形鋼で構成されている。
鋼製変形誘発部材２６Ａを構成するＨ形鋼は、図３（Ｂ）に示すように、ウェブ２４０４をトンネル１０断面のほぼ中央に対向させ、一対のフランジ２４０２をトンネル１０の掘削方向Ｘに対向させて配置されている。 The steel deformation inducing members 26A are provided at a plurality of locations spaced apart in the extending direction of the shoring 20, as shown in FIG.
The steel deformation-inducing member 26A is a steel member that deforms more proactively than the steel support member 22 when the ground load from the excavation surface 12 acts on the support 20 .
The total length of the plurality of steel deformation inducing members 26A provided in the shoring 20 is about 10% of the total length of the shoring 20, and the length of one steel deformation inducing member 26A is equal to the length of the shoring 20. It is about several percent of the total length.
In the present embodiment, the steel deformation inducing member 26A is made of the same H-section steel as the H-section steel that constitutes the steel support member 22, and more specifically, the cross-sectional shape thereof constitutes the steel support member 22. It is composed of H-section steel of the same shape and size as the H-section steel.
The H-shaped steel constituting the steel deformation inducing member 26A, as shown in FIG. Let it be arranged.

したがって、図４に示すように、鋼製変形誘発部材２６Ａを構成するＨ形鋼は、鋼製支保部材２２を構成するＨ形鋼に対して９０度向きを変えて配置されている。
また、鋼製変形誘発部材２６Ａを構成するＨ形鋼は、重量バランスを考慮してその図心を、鋼製支保部材２２を構成するＨ形鋼の図心に合致させて配置されている。
すなわち、鋼製変形誘発部材２６Ａは鋼製支保部材２２と断面積が同一であることから軸力に対しては鋼製支保部材２２と同様に機能し、曲げモーメントに対して鋼製支保部材２２よりも変形し易い部材となっている。
したがって、Ｈ形鋼の向きを変えて配置することにより、鋼製変形誘発部材２６Ａは、掘削表面１２からの地山の荷重が支保工２０に作用した際に、鋼製支保部材２２よりも率先して変形する鋼製の部材となっている。
具体的には、地山からの荷重が掘削表面１２から支保工２０に作用した際、支保工２０に生じる曲げモーメントに対しての鋼製変形誘発部材２６Ａの断面係数は、鋼製支保部材２２の断面係数よりも小さく形成されている。
この場合、鋼製変形誘発部材２６Ａの長さや断面係数は、地山からの荷重が掘削表面１２から支保工２０に作用した際の変形量を考慮して適宜設定され、Ｈ形鋼の断面係数は、図３（Ａ）に示すように、ウェブ２４０４の厚さＴ１、幅Ｗ１、一対のフランジ２４０２の厚さＴ２、幅Ｗ２により適宜決定される。 Therefore, as shown in FIG. 4 , the H-section steel forming the steel deformation inducing member 26A is arranged in a 90° orientation with respect to the H-section steel forming the steel support member 22 .
In addition, the H-section steel forming the steel deformation inducing member 26A is arranged so that its centroid coincides with the centroid of the H-section steel forming the steel support member 22 in consideration of weight balance.
That is, since the steel deformation inducing member 26A has the same cross-sectional area as the steel support member 22, it functions in the same manner as the steel support member 22 with respect to the axial force, and the steel support member 26A with respect to the bending moment. It is a member that is more easily deformed than
Thus, by reorienting the H-beams, the steel deformation-inducing members 26A are more proactive than the steel support members 22 when ground loads from the excavated surface 12 are applied to the support 20. It is a steel member that deforms.
Specifically, when a load from the ground acts on the support 20 from the excavated surface 12, the section modulus of the steel deformation inducing member 26A with respect to the bending moment generated in the support 20 is is formed smaller than the section modulus of
In this case, the length and section modulus of the steel deformation inducing member 26A are appropriately set in consideration of the deformation amount when the load from the ground acts on the shoring 20 from the excavated surface 12, and the section modulus of the H-section steel is appropriately determined by the thickness T1 and width W1 of the web 2404 and the thickness T2 and width W2 of the pair of flanges 2402, as shown in FIG. 3A.

また、図３（Ａ）に示すように、鋼製支保部材２２を構成するＨ形鋼のフランジ２４０２は、一次吹き付けのコンクリート１４Ａの表面に対して一定の間隔をおいて配置できるものの、鋼製変形誘発部材２６Ａを構成するＨ形鋼では、図３（Ｂ）に示すように一対のフランジ２４０２がトンネル１０の掘削方向Ｘに対向して配置されるため、一対のフランジ２４０２の端部が一次吹き付けのコンクリート１４Ａの表面に対して近接し、二次吹き付けコンクリート１４Ｂ（図１参照）が鋼製変形誘発部材２６Ａを構成するＨ形鋼と一次吹き付けのコンクリート１４Ａの表面との間に吹き付けられないことも考えられる。
このような場合には、図９に示すように、モルタル２８０２を充填した布などからなる細長の袋体２８を用意し、鋼製変形誘発部材２６Ａを構成するＨ形鋼の一対のフランジ２４０２とウェブ２４０４と一次吹き付けのコンクリート１４Ａの表面との間に袋体２８を配置するようにしてもよい。 Further, as shown in FIG. 3A, the H-shaped steel flange 2402 that constitutes the steel support member 22 can be arranged at a constant interval with respect to the surface of the primary sprayed concrete 14A. In the H-section steel forming the deformation inducing member 26A, the pair of flanges 2402 are arranged to face each other in the excavation direction X of the tunnel 10 as shown in FIG. It is close to the surface of the sprayed concrete 14A, and the secondary sprayed concrete 14B (see FIG. 1) is not sprayed between the H-shaped steel constituting the steel deformation inducing member 26A and the surface of the primary sprayed concrete 14A. It is also possible.
In such a case, as shown in FIG. 9, an elongated bag 28 made of cloth or the like filled with mortar 2802 is prepared, and a pair of H-shaped steel flanges 2402 constituting the steel deformation inducing member 26A and a pair of flanges 2402 are prepared. A bag 28 may be placed between the web 2404 and the surface of the primary sprayed concrete 14A.

また、図５（Ａ）、（Ｂ）に示すように、鋼製支保部材２２と鋼製変形誘発部材２６Ａとは、鋼製の連結部材を構成するプレート２９と、ボルトＢ１、ナットＮ１を介して連結されている。
すなわち、図５（Ａ）に示すように、鋼製変形誘発部材２６Ａの長手方向の両端にプレート２９が溶接により固定され、隣り合う鋼製支保部材２２の長手方向の端部にプレート２９が溶接により固定されている。
プレート２９は、図５（Ｂ）に示すように、鋼製支保部材２２と鋼製変形誘発部材２６Ａを構成するＨ形鋼がその内側に入る正方形や円形で形成され、プレート２９には２つのボルト挿通孔Ｈ１が形成されている。
そして、鋼製変形誘発部材２６Ａの両端のプレート２９に、鋼製支保部材２２の端部のプレート２９を突き合わせ、ボルト挿通孔Ｈ１に挿通したボルトＢ１にナットＮ１を螺合し、鋼製変形誘発部材２６Ａの両端のプレート２９と、鋼製支保部材２２の端部のプレート２９とを締結することで鋼製支保部材２２と鋼製変形誘発部材２６Ａとを連結している。 As shown in FIGS. 5A and 5B, the steel supporting member 22 and the steel deformation inducing member 26A are connected via a plate 29 constituting a steel connecting member, a bolt B1, and a nut N1. are concatenated.
That is, as shown in FIG. 5A, plates 29 are fixed by welding to both longitudinal ends of the steel deformation inducing members 26A, and the plates 29 are welded to the longitudinal ends of the adjacent steel supporting members 22. is fixed by
The plate 29, as shown in FIG. 5(B), is formed in a square or circular shape in which the H-shaped steel constituting the steel supporting member 22 and the steel deformation inducing member 26A is placed. A bolt insertion hole H1 is formed.
Then, the plate 29 at the end of the steel support member 22 is butted against the plate 29 at both ends of the steel deformation inducing member 26A, the bolt B1 inserted through the bolt insertion hole H1 is screwed with the nut N1, and the steel deformation is induced. By fastening the plates 29 at both ends of the member 26A and the plates 29 at the ends of the steel supporting member 22, the steel supporting member 22 and the steel deformation inducing member 26A are connected.

本実施の形態によれば、掘削表面１２にトンネル１０の周囲の地山からの荷重が作用し、トンネル断面を縮小する方向の曲げモーメントが支保工２０に作用した際、鋼製支保部材２２よりも率先して鋼製変形誘発部材２６Ａが変形することで地山の変形を吸収し、トンネル１０の周囲の地山を安定化することができる。
この場合、鋼製変形誘発部材２６Ａは鋼製の部材であり変形量を調整できることから、従来のように、トンネル１０の内側に大きく突出することもない。
したがって、本実施の形態によれば、掘削表面１２に周囲の地山からの荷重が作用した場合、鋼製支保工１６にある程度の変形を許容させることで地山の変形を吸収し、地山を安定させることができ、上述の従来技術のようにトンネル１０の内側に大きく突出することもないので、上述の従来技術に比べて覆工工事を円滑に行なえ、トンネル工事の施工期間を短縮し、コストダウンを図る上で有利となる。
また、鋼製支保部材２２および鋼製変形誘発部材２６ＡとしてＨ形鋼を用いるので、市販品から鋼製支保部材２２と鋼製変形誘発部材２６Ａとを簡単に製作でき、上述の従来技術に比べてトンネル工事の施工期間を短縮し、コストダウンを図る上で有利となる。
特に、本実施の形態では、鋼製変形誘発部材２６Ａとして、鋼製支保部材２２を構成するＨ形鋼を使用できるため、鋼製支保部材２２の製作時に、鋼製変形誘発部材２６Ａを一緒に製作でき、上述の従来技術に比べてトンネル工事の施工期間を短縮し、コストダウンを図る上で有利となる。 According to the present embodiment, when a load from the ground surrounding the tunnel 10 acts on the excavation surface 12 and a bending moment acts on the support structure 20 in a direction to reduce the tunnel cross section, the steel support member 22 Since the steel deformation inducing member 26A also takes the lead in deforming, the deformation of the natural ground can be absorbed and the natural ground around the tunnel 10 can be stabilized.
In this case, the steel deformation inducing member 26A is a member made of steel and the amount of deformation can be adjusted.
Therefore, according to the present embodiment, when a load from the surrounding natural ground acts on the excavation surface 12, the deformation of the natural ground is absorbed by allowing the steel shoring 16 to deform to some extent. can be stabilized, and unlike the above-mentioned prior art, it does not protrude greatly inside the tunnel 10; , which is advantageous for cost reduction.
In addition, since H-section steel is used as the steel supporting member 22 and the steel deformation inducing member 26A, the steel supporting member 22 and the steel deformation inducing member 26A can be easily manufactured from commercially available products, which is superior to the above-described conventional technology. This shortens the construction period for tunnel construction and is advantageous in terms of cost reduction.
In particular, in the present embodiment, the H-shaped steel constituting the steel support member 22 can be used as the steel deformation inducing member 26A. It can be manufactured, shortening the construction period for tunnel construction compared to the above-mentioned conventional technology, and is advantageous in terms of cost reduction.

次に、図６から図８を参照してプレート２９に代えて連結部材を構成するブラケット３０、ボルトＢ１、Ｂ２、ナットＮ１を介して鋼製支保部材２２と鋼製変形誘発部材２６Ａとを連結した第１の実施の形態の変形例について説明する。
図７（Ａ）に示すように、ブラケット３０は、金属製で２つ設けられている。
詳細には、図６（Ａ）、（Ｂ）に示すように、鋼製支保部材２２を構成するＨ形鋼の長手方向の端部でウェブ２４０４の幅方向の中央に、鋼製支保部材２２の長手方向に間隔をおいて２つのボルト挿通孔Ｈ１が形成されている。
また、鋼製変形誘発部材２６Ａを構成するＨ形鋼の一対のフランジ２４０２の幅方向の中央に、鋼製変形誘発部材２６Ａの長手方向に間隔をおいて２つの雌ねじＦ１が形成されている。
２つのブラケット３０は同一形状で、図８（Ａ）、（Ｂ）に示すように、細長の中央板部３００２と、中央板部３００２の長手方向の両端に屈曲部を介して接続された一対の端部板部３００４とを備えている。
中央板部３００２と一対の端部板部３００４には、それぞれ２つのボルト挿通孔Ｈ２がそれらの長手方向に間隔をおいて２つずつ形成されている。
図７（Ａ）、（Ｂ）に示すように、２つのブラケット３０の中央板部３００２は、鋼製変形誘発部材２６Ａを構成するＨ形鋼の一対のフランジ２４０２に、ボルト挿通孔Ｈ２に挿通され雌ねじＦ１に螺合するボルトＢ１で取り付けられている。
また、２つのブラケット３０の一対の端部板部３００４は、鋼製変形誘発部材２６Ａを挟んで隣り合う鋼製支保部材２２を構成するＨ形鋼のウェブ２４０４に当接され、ボルト挿通孔Ｈ１、Ｈ２に挿通されたボルトＢ２と、ボルトＢ２に螺合するナットＮ１によりＨ形鋼のウェブ２４０４に共締めされ、締結されることで取り付けられている。
このような変形例によっても第１の実施の形態と同様な効果が奏される。
なお、鋼製支保部材２２と鋼製変形誘発部材２６Ａとを連結する連結部材の構成には、従来公知の様々な構造が採用可能であるが、第１の実施の形態のようなプレート２９や、変形例のようなブラケット３０を用いると、簡単な構成で鋼製支保部材２２と鋼製変形誘発部材２６Ａとを簡単に確実に連結する上で有利となる。
なお、この第１の実施の形態とその変形例では、鋼製支保部材２２と鋼製変形誘発部材２６Ａとが同一の形鋼であるＨ形鋼で構成され、トンネルの掘削方向Ｘに対してＨ形鋼の断面形状の向きを９０度変えて配置した場合について説明した。本発明では、鋼製支保部材２２と鋼製変形誘発部材２６Ａとに用いる同一の断面形状の形鋼は、Ｈ形鋼に限定されず溝型鋼やＩ形鋼などその他の形鋼でもよく、その場合には、断面係数が大きくなる向きにして形鋼を鋼製支保部材２２として用い、断面係数が小さくなる向きにして形鋼を鋼製変形誘発部材２６Ａとして用いればよく、トンネルの掘削方向Ｘに対して形鋼の断面形状の向きを変える角度は９０度に限定されず、例えば、３０度、４５度、６０度などであってもよい。
さらに、鋼製支保部材２２を構成する形鋼と同一の断面形状であっても、鋼製支保部材２２を構成する形鋼の材料よりも、例えば強度や剛性が低い材料すなわち変形し易い材料で形成された形鋼からなるあるいは鋼材製の鋼製変形誘発部材２６Ａを用いれば、その断面形状を鋼製支保部材２２の形鋼と同じ向きで使用することが可能となる。その場合でも、トンネルの掘削方向Ｘに対して鋼製変形誘発部材２６Ａの断面形状の向きを変えて使用してもよい。無論、本発明では、鋼製支保部材２２や鋼製変形誘発部材２６Ａに用いる部材は形鋼に限定されず、鋼製支保部材２２の断面形状と鋼製変形誘発部材２６Ａの断面形状が異なった形鋼を含む鋼製の部材を用いるなど任意であり、その場合でも、鋼製支保部材２２を構成する材料よりも変形し易い材料を用いれば、鋼製変形誘発部材２６Ａを簡単に製作する上で有利となる。
また、鋼製支保部材２２の断面係数よりも断面係数が小さい鋼製変形誘発部材２６Ａを用いることで、鋼製変形誘発部材２６Ａを簡単に製作することができる。
また、本実施の形態では、鋼製変形誘発部材２６Ａの断面形状が長手方向に沿って均一である場合について説明したが、鋼製変形誘発部材２６Ａの断面形状は長手方向の沿って次第に大きくなる、あるいは、次第に小さくなる、あるいは長手方向の中間部が両端に比べて小さいなどのものを用いて鋼製支保部材２２よりも変形し易くするなど任意である。 Next, referring to FIGS. 6 to 8, the steel supporting member 22 and the steel deformation inducing member 26A are connected via a bracket 30, bolts B1 and B2, and a nut N1, which constitute connecting members in place of the plate 29. A modification of the first embodiment will be described.
As shown in FIG. 7A, two metal brackets 30 are provided.
Specifically, as shown in FIGS. 6A and 6B, the steel support member 22 is placed in the center of the width direction of the web 2404 at the longitudinal ends of the H-shaped steel forming the steel support member 22 . are formed with two bolt insertion holes H1 spaced apart in the longitudinal direction.
Also, two internal threads F1 are formed at intervals in the longitudinal direction of the steel deformation inducing member 26A at the center in the width direction of the pair of H-shaped steel flanges 2402 that constitute the steel deformation inducing member 26A.
The two brackets 30 have the same shape, and as shown in FIGS. 8A and 8B, an elongate central plate portion 3002 and a pair of brackets connected to both longitudinal ends of the central plate portion 3002 via bent portions. and an end plate portion 3004 of .
Two bolt insertion holes H2 are formed in the central plate portion 3002 and the pair of end plate portions 3004 at intervals in the longitudinal direction.
As shown in FIGS. 7A and 7B, the central plate portions 3002 of the two brackets 30 are inserted into the pair of H-shaped steel flanges 2402 constituting the steel deformation inducing member 26A and through the bolt insertion holes H2. It is mounted with a bolt B1 screwed into the internal thread F1.
Also, the pair of end plate portions 3004 of the two brackets 30 are in contact with the H-shaped steel webs 2404 forming the steel support members 22 adjacent to each other with the steel deformation inducing member 26A interposed therebetween, and the bolt insertion holes H1. , H2 and a nut N1 screwed onto the bolt B2 are fastened together to the web 2404 of the H-section steel, and are fastened.
Such a modified example also provides the same effects as the first embodiment.
Various conventionally known structures can be employed for the structure of the connecting member that connects the steel supporting member 22 and the steel deformation inducing member 26A. The use of the bracket 30 of the modified example is advantageous in that the steel supporting member 22 and the steel deformation inducing member 26A can be easily and reliably connected with a simple configuration.
In the first embodiment and its modification, the steel supporting member 22 and the steel deformation inducing member 26A are made of H-shaped steel, which is the same shaped steel. A case where the direction of the cross-sectional shape of the H-shaped steel is changed by 90 degrees has been described. In the present invention, the shaped steel having the same cross-sectional shape used for the steel supporting member 22 and the steel deformation inducing member 26A is not limited to H-shaped steel, but may be other shaped steel such as channel steel or I-shaped steel. In this case, the shaped steel may be used as the steel support member 22 in the direction of increasing the section modulus, and the shaped steel may be used as the steel deformation inducing member 26A in the direction of decreasing the section modulus. The angle at which the cross-sectional shape of the shaped steel changes direction is not limited to 90 degrees, and may be, for example, 30 degrees, 45 degrees, or 60 degrees.
Furthermore, even if the cross-sectional shape is the same as that of the shaped steel that constitutes the steel supporting member 22, a material having, for example, lower strength and rigidity than the material of the shaped steel that constitutes the steel supporting member 22, that is, a material that is easily deformed is used. Using a steel deformation inducing member 26A made of formed steel or made of steel allows its cross-sectional shape to be used in the same orientation as the steel support member 22 shape. Even in that case, the direction of the cross-sectional shape of the steel deformation inducing member 26A may be changed with respect to the excavation direction X of the tunnel. Of course, in the present invention, the members used for the steel supporting member 22 and the steel deformation inducing member 26A are not limited to shaped steel, and the cross-sectional shape of the steel supporting member 22 and the steel deformation inducing member 26A are different. It is optional to use a steel member including shaped steel. Even in that case, if a material that is more deformable than the material constituting the steel supporting member 22 is used, the steel deformation inducing member 26A can be easily manufactured. is advantageous.
Further, by using the steel deformation inducing member 26A having a section modulus smaller than that of the steel supporting member 22, the steel deformation inducing member 26A can be easily manufactured.
Also, in the present embodiment, the case where the cross-sectional shape of the steel deformation inducing member 26A is uniform along the longitudinal direction has been described, but the cross-sectional shape of the steel deformation inducing member 26A gradually increases along the longitudinal direction. Alternatively, it is optional to make it easier to deform than the steel supporting member 22 by using a member that gradually becomes smaller, or that the intermediate portion in the longitudinal direction is smaller than both ends.

（第２の実施の形態）
次に、本発明の第２の実施の形態について図１０～図１２を参照して説明する。
なお、以下の実施の形態では、第１の実施の形態と同様な箇所、部材には同一の符号を付してその説明を省略あるいは簡略し、第１の実施の形態と異なった箇所を重点的に説明する。
第２の実施の形態では、図１０に示すように、鋼製変形誘発部材２６Ｂが、ウェブ２４１４と、前記ウェブ２４１４の両端から起立する一対のフランジ２４１２とからなる溝型鋼で構成されている点が第１の実施の形態と異なっている。
鋼製支保部材２２は、第１の実施の形態と同様に、一対のフランジ２４０２を、トンネル断面のほぼ中央に対向させ、ウェブ２４０４をトンネル１０の掘削方向Ｘに対向させて配置したＨ形鋼で構成されている。
すなわち、第２の実施の形態では、鋼製支保部材２２と鋼製変形誘発部材２６Ｂとは、互いに形状の異なる形鋼で構成されている。
図１０に示すように、溝型鋼は、平面視した場合、溝型鋼の図心をＨ形鋼の図心に合致させて配置されている。
溝型鋼は、ウェブ２４１４をトンネル断面の中央に対向させて配置されている。
第１の実施の形態と同様に、鋼製変形誘発部材２６Ｂの長さや断面係数は、地山からの荷重が掘削表面１２から支保工２０に作用した際の変形量を考慮して適宜設定され、地山からの荷重が掘削表面１２から支保工２０に作用した際、支保工２０に生じる曲げモーメントに対しての鋼製変形誘発部材２６Ｂの断面係数は、鋼製支保部材２２の断面係数よりも小さく形成され、鋼製変形誘発部材２６Ｂは鋼製支保部材２２よりも変形し易い部材となっている。 (Second embodiment)
Next, a second embodiment of the invention will be described with reference to FIGS. 10 to 12. FIG.
In the following embodiments, the same reference numerals are given to the same parts and members as in the first embodiment, and the description thereof is omitted or simplified, and the parts different from the first embodiment are emphasized. explained in detail.
In the second embodiment, as shown in FIG. 10, the steel deformation inducing member 26B is made of channel steel consisting of a web 2414 and a pair of flanges 2412 standing from both ends of the web 2414. is different from the first embodiment.
As in the first embodiment, the steel support members 22 are H-section steels arranged with a pair of flanges 2402 opposed to substantially the center of the tunnel cross section and webs 2404 opposed to the excavation direction X of the tunnel 10. consists of
That is, in the second embodiment, the steel supporting member 22 and the steel deformation inducing member 26B are made of shaped steel having different shapes.
As shown in FIG. 10, the channel steel is arranged so that the centroid of the channel steel matches the centroid of the H-section steel when viewed from above.
The channel steel is placed with the web 2414 facing the center of the tunnel cross-section.
As in the first embodiment, the length and section modulus of the steel deformation inducing member 26B are appropriately set in consideration of the amount of deformation when the load from the ground acts on the shoring 20 from the excavated surface 12. , the section modulus of the steel deformation inducing member 26B with respect to the bending moment generated in the shoring 20 when the load from the ground acts on the shoring 20 from the excavated surface 12 is greater than the section modulus of the steel supporting member 22 Also, the steel deformation inducing member 26B is a member that deforms more easily than the steel support member 22. As shown in FIG.

鋼製支保部材２２と鋼製変形誘発部材２６Ｂとは、図１１、図１２に示すように、ブラケット３２とボルトＢ３、Ｂ４を介して連結されている。
詳細には、図１１（Ｂ）に示すように、鋼製支保部材２２を構成するＨ形鋼の長手方向の端部で一対のフランジ２４０２の幅方向両側に２つの雌ねじＦ２が形成されている。
また、図１１Ａ）、（Ｂ）に示すように、鋼製変形誘発部材２６Ｂを構成する溝型鋼の２つのフランジ２４１２には、それぞれ雌ねじＦ３が形成されている。 As shown in FIGS. 11 and 12, the steel supporting member 22 and the steel deformation inducing member 26B are connected to the bracket 32 via bolts B3 and B4.
Specifically, as shown in FIG. 11(B), two internal threads F2 are formed on both sides in the width direction of a pair of flanges 2402 at the longitudinal ends of the H-shaped steel that constitutes the steel support member 22. .
Also, as shown in FIGS. 11A and 11B, female threads F3 are formed in two flanges 2412 of channel steel forming the steel deformation inducing member 26B.

ブラケット３２は、２つ設けられている。
２つのブラケット３２は同一形状で、図１２（Ａ）、（Ｂ）、（Ｃ）に示すように、中央板部３２０２と、中央板部３２０２の両端から屈曲された一対の端部板部３２０４とを備えている。
一対の端部板部３２０４は、それらの間にＨ形鋼の一対のフランジ２４０２が挿入される寸法で形成されている。
中央板部３２０２には２つのボルト挿通孔Ｈ３が形成され、一対の端部板部３２０４には、それぞれ２つのボルト挿通孔Ｈ４が形成されている。
図１１（Ａ）、（Ｂ）に示すように、２つのブラケット３２の中央板部３２０２は、鋼製変形誘発部材２６Ｂを構成する溝型鋼の端部に突き当てられると共に、鋼製支保部材２２の端部に突き当てられ、また、一対の端部板部３２０４はＨ形鋼の一対のフランジ２４０２に合わされ、一対の端部板部３２０４のボルト挿通孔Ｈ４に挿通され一対のフランジ２４０２の雌ねじＦ２に螺合するボルトＢ３で２つのブラケット３２はＨ形鋼の端部に取り付けられている。
また、中央板部３２０２のボルト挿通孔Ｈ３に挿通され溝型鋼のフランジ２４１２の雌ねじＦ３に螺合するボルトＢ４により、ブラケット３２は溝型鋼に取り付けられている。 Two brackets 32 are provided.
The two brackets 32 have the same shape and, as shown in FIGS. and
A pair of end plates 3204 are sized to allow a pair of H-beam flanges 2402 to be inserted therebetween.
Two bolt insertion holes H3 are formed in the center plate portion 3202, and two bolt insertion holes H4 are formed in the pair of end plate portions 3204, respectively.
As shown in FIGS. 11A and 11B, the central plate portions 3202 of the two brackets 32 are abutted against the ends of the channel steel forming the steel deformation inducing member 26B, and the steel support member 22 Also, the pair of end plate portions 3204 are matched with a pair of flanges 2402 of H-shaped steel, are inserted into the bolt insertion holes H4 of the pair of end plate portions 3204, and the female threads of the pair of flanges 2402 Two brackets 32 are attached to the ends of the H-beam with bolts B3 that screw into F2.
The bracket 32 is attached to the channel steel by a bolt B4 that is inserted through the bolt insertion hole H3 of the central plate portion 3202 and screwed into the internal thread F3 of the flange 2412 of the channel steel.

このような第２の実施の形態によっても、第１の実施の形態と同様に、鋼製変形誘発部材２６Ｂは鋼製支保部材２２よりも変形し易く、掘削表面１２にトンネル１０の周囲の地山からの荷重が作用し、トンネル断面を縮小する方向の曲げモーメントが支保工２０に作用した際、鋼製支保部材２２よりも率先して鋼製変形誘発部材２６Ｂが変形することで地山の変形を吸収し、トンネル１０の周囲の地山を安定化することができる。
この場合、鋼製変形誘発部材２６Ｂは鋼製の部材であり変形量を調整できることから、従来のように、トンネル１０の内側に大きく突出することもない。
したがって、掘削表面１２に周囲の地山からの荷重が作用した場合、鋼製支保工１６にある程度の変形を許容させることで地山の変形を吸収し、地山を安定させることができ、上述の従来技術のようにトンネル１０の内側に大きく突出することもないので、上述の従来技術に比べて覆工工事を円滑に行なえ、トンネル工事の施工期間を短縮し、コストダウンを図る上で有利となる。
また、鋼製支保部材２２としてＨ形鋼を用い、鋼製変形誘発部材２６Ｂとして溝型鋼を用いるので、市販品から鋼製支保部材２２と鋼製変形誘発部材２６Ｂとを簡単に製作でき、上述の従来技術に比べてトンネル工事の施工期間を短縮し、コストダウンを図る上で有利となる。
なお、形鋼としてＨ形鋼、溝型鋼の他に，Ｉ形鋼や山形鋼、丸鋼などがあり、本発明において鋼製支保部材２２や鋼製変形誘発部材２６Ｂを構成する形鋼として、それらを任意に組み合わせて使用するなどしてもよい。 According to the second embodiment, as in the first embodiment, the steel deformation inducing member 26B deforms more easily than the steel support member 22, and the ground around the tunnel 10 is applied to the excavation surface 12. When a load from the mountain acts and a bending moment acts on the support structure 20 in a direction that reduces the tunnel cross section, the steel deformation inducing member 26B deforms more than the steel support member 22, thereby It is possible to absorb the deformation and stabilize the natural ground around the tunnel 10. - 特許庁
In this case, since the steel deformation inducing member 26B is a member made of steel and the amount of deformation can be adjusted, it does not protrude greatly inside the tunnel 10 unlike the conventional case.
Therefore, when a load from the surrounding natural ground acts on the excavation surface 12, the deformation of the natural ground can be absorbed by allowing the steel shoring 16 to deform to some extent, and the natural ground can be stabilized. Since it does not protrude greatly inside the tunnel 10 unlike the prior art, the lining work can be performed more smoothly than the above-mentioned prior art, which is advantageous in terms of shortening the tunnel construction period and reducing costs. becomes.
In addition, since H-shaped steel is used as the steel supporting member 22 and channel steel is used as the steel deformation inducing member 26B, the steel supporting member 22 and the steel deformation inducing member 26B can be easily manufactured from commercially available products. It is advantageous in terms of shortening the construction period for tunnel construction and reducing costs compared to the conventional technology.
In addition to H-shaped steel and channel steel, there are I-shaped steel, angle steel, round steel, etc. as shaped steel. Any combination of them may be used.

（第３の実施の形態）
次に、本発明の第３の実施の形態について図１３～図１５を参照して説明する。
第３の実施の形態では、図１３に示すように、鋼製変形誘発部材２６Ｃが鉄筋で構成されている点が第１の実施の形態と異なっている。
鋼製支保部材２２は、第１の実施の形態と同様に、一対のフランジ２４０２を、トンネル断面のほぼ中央に対向させ、ウェブ２４０４をトンネル１０の掘削方向Ｘに対向させて配置したＨ形鋼で構成されている。
鋼製変形誘発部材２６Ｃを構成する鉄筋は、鉄筋の図心をＨ形鋼の図心に合致させて配置されている。
第１の実施の形態と同様に、鋼製変形誘発部材２６Ｃの長さや断面係数は、地山からの荷重が掘削表面１２から支保工２０に作用した際の変形量を考慮して適宜設定され、地山からの荷重が掘削表面１２から支保工２０に作用した際、支保工２０に生じる曲げモーメントに対しての鋼製変形誘発部材２６Ｃの断面係数は、鋼製支保部材２２の断面係数よりも小さく形成され、鋼製変形誘発部材２６Ｃは鋼製支保部材２２よりも変形し易い部材となっている。 (Third Embodiment)
Next, a third embodiment of the invention will be described with reference to FIGS. 13 to 15. FIG.
As shown in FIG. 13, the third embodiment differs from the first embodiment in that steel deformation inducing members 26C are made of reinforcing bars.
As in the first embodiment, the steel support members 22 are H-section steels arranged with a pair of flanges 2402 opposed to substantially the center of the tunnel cross section and webs 2404 opposed to the excavation direction X of the tunnel 10. consists of
The reinforcing bars that constitute the steel deformation inducing member 26C are arranged so that the centroids of the reinforcing bars match the centroids of the H-section steel.
As in the first embodiment, the length and section modulus of the steel deformation inducing member 26C are appropriately set in consideration of the amount of deformation when the load from the ground acts on the shoring 20 from the excavated surface 12. , the section modulus of the steel deformation inducing member 26C with respect to the bending moment generated in the shoring 20 when the load from the ground acts on the shoring 20 from the excavated surface 12 is greater than the section modulus of the steel supporting member 22 Also, the steel deformation inducing member 26C is formed to be a member that deforms more easily than the steel support member 22. As shown in FIG.

鋼製支保部材２２と鋼製変形誘発部材２６Ｃとは、図１４に示すように、ブラケット３４とボルトＢ５を介して連結されている。
詳細には、図１４（Ａ）、（Ｂ）に示すように、鋼製支保部材２２を構成するＨ形鋼の長手方向の端部で一対のフランジ２４０２の幅方向両側に２つの雌ねじＦ４が形成されている。 As shown in FIG. 14, the steel supporting member 22 and the steel deformation inducing member 26C are connected to the bracket 34 via bolts B5.
Specifically, as shown in FIGS. 14A and 14B, two internal threads F4 are provided on both sides in the width direction of a pair of flanges 2402 at the longitudinal ends of the H-shaped steel that constitutes the steel support member 22. formed.

ブラケット３４は、金属製で２つ設けられている。
２つのブラケット３４は同一形状で、図１５（Ａ）、（Ｂ）、（Ｃ）に示すように、ブラケット本体３４０２と、筒状部材３４０４とを備えている。
ブラケット本体３４０２は、中央板部３４１２と、中央板部３４１２の両端から屈曲された一対の端部板部３４１４とを備えている。
一対の端部板部３４１４は、それらの間に鋼製支保部材２２を構成するＨ形鋼の一対のフランジ２４０２が挿入される寸法で形成されている。
一対の端部板部３４１４には、それぞれ２つのボルト挿通孔Ｈ５が形成されている。
筒状部材３４０４の内径は、鋼製変形誘発部材２６Ｃを構成する鉄筋の端部が嵌合される寸法で形成され、中央板部３４１２の中央に溶接で取り付けられている。
図１４（Ａ）、（Ｂ）に示すように、鋼製変形誘発部材２６Ｃを構成する鉄筋の両端に筒状部材３４０４が嵌合され、一対の端部板部３４１４が一対のフランジ２４０２に合わされ、一対の端部板部３４１４のボルト挿通孔Ｈ５に挿通され一対のフランジ２４０２の雌ねじＦ４に螺合するボルトＢ５で２つのブラケット３４はＨ形鋼の端部に取り付けられている。 Two brackets 34 are provided and are made of metal.
The two brackets 34 have the same shape, and include a bracket body 3402 and a tubular member 3404 as shown in FIGS.
The bracket body 3402 includes a central plate portion 3412 and a pair of end plate portions 3414 bent from both ends of the central plate portion 3412 .
The pair of end plates 3414 are sized to allow the pair of H-section steel flanges 2402 that form the steel support member 22 to be inserted therebetween.
Two bolt insertion holes H5 are formed in the pair of end plate portions 3414, respectively.
The inner diameter of the cylindrical member 3404 is formed to have a size that allows the ends of the reinforcing bars forming the steel deformation inducing member 26C to be fitted, and is attached to the center of the central plate portion 3412 by welding.
As shown in FIGS. 14A and 14B, cylindrical members 3404 are fitted to both ends of the reinforcing bars forming the steel deformation inducing member 26C, and a pair of end plate portions 3414 are fitted to a pair of flanges 2402. The two brackets 34 are attached to the ends of the H-section steel with bolts B5 that are inserted through the bolt holes H5 of the pair of end plate portions 3414 and screwed into the female threads F4 of the pair of flanges 2402 .

このような第３の実施の形態によっても、第１の実施の形態と同様に、掘削表面１２にトンネル１０の周囲の地山からの荷重が作用し、トンネル断面を縮小する方向の曲げモーメントが支保工２０に作用した際、鋼製変形誘発部材２６Ｃは鋼製支保部材２２よりも変形し易く、鋼製支保部材２２よりも率先して鋼製変形誘発部材２６Ｃが変形することで地山の変形を吸収し、トンネル１０の周囲の地山を安定化することができる。
この場合、鋼製変形誘発部材２６Ｃは鋼製の部材であり変形量を調整できることから、従来のように、トンネル１０の内側に大きく突出することもない。
したがって、掘削表面１２に周囲の地山からの荷重が作用した場合、鋼製支保工１６にある程度の変形を許容させ荷重を逃がすことで地山を安定させることができ、上述の従来技術のようにトンネル１０の内側に大きく突出することもないので、上述の従来技術に比べて覆工工事を円滑に行なえ、トンネル工事の施工期間を短縮し、コストダウンを図る上で有利となる。
また、鋼製支保部材２２としてＨ形鋼を用い、鋼製変形誘発部材２６Ｃとして鉄筋を用いるので、市販品から鋼製支保部材２２と鋼製変形誘発部材２６Ｃとを簡単に製作でき、上述の従来技術に比べてトンネル工事の施工期間を短縮し、コストダウンを図る上で有利となる。 According to the third embodiment, as in the first embodiment, a load from the ground around the tunnel 10 acts on the excavated surface 12, and a bending moment in the direction of reducing the tunnel cross section is generated. When acting on the support structure 20, the steel deformation inducing member 26C deforms more easily than the steel supporting member 22, and the deformation of the steel deformation inducing member 26C takes the lead over the steel supporting member 22. It is possible to absorb the deformation and stabilize the natural ground around the tunnel 10. - 特許庁
In this case, the steel deformation inducing member 26C is a member made of steel and the amount of deformation can be adjusted.
Therefore, when a load from the surrounding natural ground acts on the excavation surface 12, the natural ground can be stabilized by allowing the steel shoring 16 to deform to some extent and releasing the load. Moreover, since it does not protrude greatly inside the tunnel 10, the lining work can be carried out more smoothly than in the above-described prior art, which is advantageous in terms of shortening the construction period of the tunnel work and reducing the cost.
In addition, since H-shaped steel is used as the steel support member 22 and a reinforcing bar is used as the steel deformation inducing member 26C, the steel support member 22 and the steel deformation inducing member 26C can be easily manufactured from commercially available products. Compared to the conventional technology, the construction period for tunnel construction can be shortened, which is advantageous in reducing costs.

１０トンネル
１２掘削表面
１４吹き付けコンクリート
１４Ａ一次吹き付けのコンクリート
１４Ｂ二次吹き付けのコンクリート
１６鋼製支保工
１８ロックボルト
２０支保工
２２鋼製支保部材
２４０２，２４１２フランジ
２４０４、２４１４ウェブ
２６Ａ、２６Ｂ、２６Ｃ鋼製変形誘発部材
２８袋体
２８０２モルタル
２９プレート
３０、３２、３４ブラケット
３００２，３２０２，３４１２中央板部
３００４，３２０４，３４１４端部板部
３４０２ブラケット本体
３４０４筒状部材
Ｂ１、Ｂ２、Ｂ３、Ｂ４、Ｂ５ボルト
Ｆ１，Ｆ２、Ｆ３、Ｆ４雌ねじ
Ｈ１、Ｈ２、Ｈ３、Ｈ４、Ｈ５ボルト挿通孔
Ｎ１ナット 10 tunnel 12 excavation surface 14 shotcrete 14A primary shotcrete 14B secondary shots concrete 16 steel shoring 18 rock bolt 20 shoring 22 steel shoring members 2402, 2412 flanges 2404, 2414 webs 26A, 26B, 26C steel Deformation inducing member 28 Bag 2802 Mortar 29 Plates 30, 32, 34 Brackets 3002, 3202, 3412 Central plate portions 3004, 3204, 3414 End plate portions 3402 Bracket main body 3404 Tubular members B1, B2, B3, B4, B5 Bolts F1, F2, F3, F4 Internal threads H1, H2, H3, H4, H5 Bolt insertion hole N1 Nut

Claims

A steel shoring constructed along the excavation surface for supporting the excavation surface in cooperation with shotcrete sprayed onto the excavation surface of an excavated tunnel,
The steel support includes a support constructed by connecting a plurality of steel support members extending along the excavation surface in a plane orthogonal to the excavation direction of the tunnel,
Steel deformation inducing members that are more easily deformed than the steel support members are arranged at a plurality of locations spaced apart in the extending direction of the support.
A steel shoring characterized by:

The length, cross-sectional shape, or section modulus of the steel deformation-inducing member along the extension direction of the shoring, or the material that constitutes the steel deformation-inducing member is such that the load from the natural ground is applied from the excavation surface to the shoring. is set in consideration of the amount of deformation of the steel deformation inducing member when acting on
The steel shoring according to claim 1, characterized in that:

The steel supporting member and the steel deformation inducing member are made of the same shaped steel,
The steel supporting member and the steel deformation inducing member are arranged in such a manner that the direction of the cross-sectional shape of the shaped steel is changed with respect to the excavation direction of the tunnel.
The steel shoring according to claim 1 or 2, characterized in that:

The steel support member and the steel deformation-inducing member are both constructed of the same H-section steel consisting of a pair of flanges and a web connecting the flanges,
The H-shaped steel constituting the steel support member is arranged with the web facing the excavation direction of the tunnel,
The H-shaped steel constituting the steel deformation inducing member is arranged with the web facing the center of the tunnel cross section,
The steel shoring according to claim 3, characterized in that:

The steel supporting member and the steel deformation inducing member are composed of shaped steels having different shapes,
The steel shoring according to claim 1 or 2, characterized in that:

The steel support member is constructed of H-beam steel consisting of a pair of flanges and a web connecting the flanges,
The H-section steel is arranged with the web facing the direction of excavation of the tunnel,
The steel deformation inducing member is made of channel steel consisting of a web and a pair of flanges standing from both ends of the web,
The channel steel is arranged with the web facing the center of the tunnel cross-section,
The steel shoring according to claim 5, characterized in that:

The steel support member is made of shaped steel,
The steel deformation inducing member is composed of a reinforcing bar,
The steel shoring according to claim 1 or 2, characterized in that:

the steel deformation-inducing member has a section modulus smaller than the section modulus of the steel support member;
The steel shoring according to any one of claims 1 to 7, characterized in that:

The steel deformation inducing member is made of a material that is more deformable than the steel supporting member,
The steel shoring according to any one of claims 1 to 7, characterized in that:

The steel supporting member and the steel deformation inducing member are connected via a connecting member,
The steel shoring according to any one of claims 1 to 9, characterized in that: