JP2004108094A - Shield tunnel and shield excavator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shield tunnel which is strong in water pressure, earth pressure and buoyancy, reduces the volume of an overburden when applied to a road tunnel, and secures an excavation passage and an emergency vehicle passage. <P>SOLUTION: The lower edge of the cross section of the tunnel is formed like an arcuate line 2 of a small curvature and the upper edge of the same is formed like an arcuate line 3 of a large curvature or a straight line. In the tunnel, the lower edge of the cross section perpendicular to the axial direction of each of a shield cylinder 21, a bulkhead 22, a hood 23, and a tail 24 is formed like an arcuate line 25 of a small curvature, and the upper end of the same is formed like a straight line, an arcuate line 26 of a large curvature, or a parabola. Further a cutter head 35 is formed similar to the cross section perpendicular to the axial direction of each of the shield cylinder 21, the bulkhead 22, the hood 23, and the tail 24, and the tunnel is excavated by an excavator which is constructed by connecting the cutter head 35 to a rotation driving section 27 via a parallel crank moving mechanism 30. <P>COPYRIGHT: (C)2004,JPO

Description

ここで、Θは地上よりトンネルのアプローチ部分までの道路勾配である。
【００２９】
本発明の実施例１のシールドトンネル１によれば、円形断面のシールドトンネル１９に比べて道路延長を２Ｌ、短縮することができる。したがって、トンネル構築のための機材や資材を節減できる外、工期を短縮することができる。
【００３０】
また、この実施例１のシールドトンネル１によれば、地中でトンネル構築作業が行われるので、海域や河域の汚染を解消できるという、シールド工法の利点をそのまま活かすことができる。
【００３１】
【実施例２】
ついで、図４は本発明シールドトンネルの実施例２を示す断面図である。
【００３２】
この図４に示す実施例２のシールドトンネルは、トンネル断面の下部がＯ_１　を中心とする半径Ｒ_１の小曲率の円弧形１３に形成され、中間部が矩形１４に形成され、上部がＯ_２を中心とする半径Ｒ_２（Ｒ_２＞Ｒ_１）の大曲率の円弧形１５に形成されている。
【００３３】
また、路床５は埋め戻し土を再利用して造成されている。
【００３４】
なお、図４において、符号１６は路盤を示す。
【００３５】
この実施例２におけるシールドトンネルは、トンネル断面の上・下部間に、矩形１４の中間部を介在させて、トンネル全体の高さを高く構成している外は、前記実施例１のシールドトンネル１の形状と同様であり、作用も同様である。
【００３６】
【実施例３】
続いて、図５は本発明シールドトンネルの実施例３を示す断面図である。
【００３７】
この図５に示す実施例３のシールドトンネルは、トンネル断面の下部が小曲率のほぼ円弧形１７に形成され、上部がほぼ平面状１８に形成されている。
【００３８】
また、路床５は掘削土砂を埋め戻して造成されている。
【００３９】
この実施例３のシールドトンネルでは、トンネル断面の上部を平面状１８に形成しているが、土被り荷重が小さい場合、強度上の問題は生じない。
【００４０】
この実施例３のシールドトンネルの他の構成は、前記実施例１のシールドトンネル１と同様であり、作用についても実施例１のシールドトンネル１と同様である。
【００４１】
なお、本発明におけるシールドトンネルの、トンネル断面の上部の形状は、図１および図４では大曲率のほぼ円弧形３，１５としたが、放物線状であっても良く、または図５に示したように直線状としても良く、これらの範囲であれば良い。
【００４２】
【実施例４】
つぎに、図６〜図８は本発明の実施例１のシールドトンネルを掘削するためのシールド掘削機の一実施例を示すもので、図６は縦断側面図、図７は正面図、図８は背面図である。
【００４３】
これら図６〜図８に示す実施例のシールド掘削機２０は、シールド筒２１と、隔壁２２と、フード部２３と、テール部２４と、カッタヘッド用の回転駆動部２７および平行クランク運動機構３０と、カッタヘッド３５と、掘削土砂用のチャンバ３９と、排土装置４０と、推進ジャッキ４３等を備えて構成されている。
【００４４】
前記シールド筒２１と、隔壁２２と、フード部２３と、テール部２４とは、シールド掘削機１の軸方向に対する直角断面の下部が小曲率のほぼ円弧形２５に形成され、上部が大曲率のほぼ円弧形２６に形成されている。
【００４５】
前記カッタヘッド用の回転駆動部２７は、図４に示すように、駆動モータ２８と、これに連結されたピニオン２９とを有している。
【００４６】
前記カッタヘッド用の平行クランク運動機構３０は、前記ピニオン２９に噛み合わされたインターナルギヤ３１と、このインターナルギヤ３１と一体に形成されかつ隔壁２２に回転自在に支持された回転体３２と、この回転体３２の中心に対して偏心距離ｅ、偏心させて設けられた偏心軸３３とを有している。
【００４７】
そして、前記回転駆動部２７と平行クランク運動機構３０とは、所要の間隔をおいて、この実施例では５組配置されており、前記５組の回転駆動部２７と平行クランク運動機構３０とが協働してカッタヘッド３５を平行クランク運動させ得るように構成されている。
【００４８】
前記回転体３２の中心部には、機内からチャンバ３９に向かって作泥土材注入口３４が設けられている。
【００４９】
前記カッタヘッド３５は、カッタフレーム３６と、このカッタフレーム３６に多数植設されたカッタビット３７とを有している。前記カッタフレーム３６は、図５から分かるように、前記シールド筒２１、隔壁２２、フード部２３およびテール部２４と近似形に形成されている。なお、カッタビット３７については、図４にビット列の外郭を仮想線で示し、個々のカッタビットの配列を省略している。
【００５０】
前記カッタフレーム３６におけるチャンバ３９側の面には、複数本の攪拌翼３８が設けられている。
【００５１】
前記チャンバ３９は、隔壁２２、フード部２３およびカッタヘッド３５に囲まれた空間に形成されている。
【００５２】
前記排土装置４０には、この実施例ではスクリューコンベアが用いられている。この排土装置４０は、駆動部４１と、排土口４２とを有しており、入口部分を前記チャンバ３９に臨ませて設置されている。
【００５３】
前記推進ジャッキ４３は、シールド筒２１の内部において、円周方向に所定の間隔をおいて複数台設置されている。
【００５４】
この実施例におけるシールド筒２０は、地中において、複数組の回転駆動部２７が同時にかつ同じ方向に駆動されると、各回転駆動部２７に連結された平行クランク運動機構３０が連動し、複数組の平行クランク運動機構３０によりカッタヘッド３５が平行クランク運動する。
【００５５】
前記カッタヘッド３５が平行クランク運動を行うに伴い、カッタビット列３７により切羽が掘削され、その掘削土砂はチャンバ３９に取り込まれる。
【００５６】
前述のごとく、チャンバ３９に取り込まれた掘削土砂には、作泥土材注入口３４から作泥土材が注入され、掘削土砂と作泥土材とがカッタフレーム３６に設けられた攪拌翼３８により攪拌され、塑性流動性を有する土砂が作成される。
【００５７】
そして、掘進に伴って排土装置４０が駆動され、切羽の崩壊を防止しつつ排土装置４０にチャンバ３９内の土砂が取り込まれ、排土口４２を通じてシールド掘削機２０の後方へ排土される。
【００５８】
また、シールド掘削機２０内の後部でセグメント４４を組み立てて行く。
【００５９】
前述のごとくチャンバ３９内の土砂を排出し、セグメント４４を組み立てた後、複数台の推進ジャッキ４３を同時に伸長させ、セグメント４４に反力を取ってシールド掘削機２０全体を推進させる。
【００６０】
ついで、各推進ジャッキ４３を収縮させ、再びシールド掘削機２０の後部でセグメント４４を組み立てる。
【００６１】
以上の作業を繰り返して行い、シールドトンネルを掘進する。
【００６２】
以上説明したシールド掘削機２０によれば、シールド筒２１、隔壁２２、フード部２３およびテール部２４の軸方向に対する直角断面の下部を小曲率のほぼ円弧形２５に形成し、上部を大曲率のほぼ円弧形２６に形成し、カッタヘッド３５を前記シールド筒２１、隔壁２２、フード部２３およびテール部２４の直角断面形状と近似形に形成し、このカッタヘッド３５を平行クランク運動機構３０を介して回転駆動部２７に連結しているので、前記図１に示す実施例１のシールドトンネル１を的確に掘削することができる。
【００６３】
なお、図４に示す実施例２のシールドトンネル、図５に示す実施例３のシールドトンネルを掘削するシールド掘削機では、シールド筒２１、隔壁２２、フード部２３およびテール部２４をそれぞれ掘削すべきトンネル断面に対応する形状に形成するとともに、カッタヘッド３５を当該トンネル断面に近似の形状に形成する。
【００６４】
【発明の効果】
以上説明した本発明のシールドトンネルでは、トンネル断面の下部を小曲率のほぼ円弧形２，１３，１７に形成しているので、水圧・土圧に対する強度を大きくなし得る効果があり、トンネル内の下部に土砂等を埋め込んでトンネルの重量を増大させ、トンネルに掛かる浮力に対抗させ、トンネルの安定化を図り得る効果があり、道路トンネルとしての用途では、トンネル内の下部に避難通路９や緊急車両通行路を確保し得る効果があり、さらにトンネル断面の上部を大曲率のほぼ円弧形３，１５、ほぼ平面状１８に形成しているので、道路トンネルの場合に、円形断面のシールドトンネルに比べて、道路延長を短縮し得る効果があり、ひいてはトンネル構築のための機材や資材を節減できる外、工期を短縮し得る効果があり、地中でトンネル構築作業を行うので、海域や河域の汚染を解消できるという、シールド工法の利点をそのまま活かし得る効果をも有する。
【００６５】
また、本発明のシールド掘削機ではシールド筒２１、隔壁２２、フード部２３およびテール部２４の軸方向に対する直角断面の下部を、小曲率のほぼ円弧形２５に形成し、上部を直線状ないしは大曲率のほぼ円弧形２６、放物線状に形成し、カッタヘッド３５を前記シールド筒２１、隔壁２２、フード部２３およびテール部２４の直角断面形状と近似形に形成し、前記カッタヘッド３５を、平行クランク運動機構３０を介して回転駆動部２７に連結しているので、前記本発明にかかるシールドトンネルを的確に掘削し得る効果がある。
【図面の簡単な説明】
【図１】本発明シールドトンネルの実施例１を示す断面図である。
【図２】土被りを同一にしたときの、本発明の実施例１のシールドトンネルと、円形断面のシールドトンネルとについて、縦断線形の深さを比較して示した図である。
【図３】図２に示す両シールドトンネルの縦断線形深さと、トンネルのアプローチ部分の道路延長との関係を比較して示した図である。
【図４】本発明のシールドトンネルの実施例２を示す断面図である。
【図５】本発明シールドトンネルの実施例３を示す断面図である。
【図６】本発明シールド掘削機の一実施例を示す縦断側面図である。
【図７】同シールド掘削機の正面図である。
【図８】同シールド掘削機の背面図である。
【符号の説明】
１　　シールドトンネル
２　　トンネル断面の下部における小曲率のほぼ円弧形
３　　トンネル断面の上部における大曲率のほぼ円弧形
４　　セグメント
５　　路床
６　　路盤コンクリート
７　　連結部材
８　　柱壁
８’　桁材
９　　避難通路
１２　道路
Ｄ　　土被り
１３　トンネル断面の下部における小曲率のほぼ円弧形
１５　トンネル断面の上部における大曲率のほぼ円弧形
１６　路盤
１７　トンネル断面の下部における小曲率のほぼ円弧形
１８　トンネル断面の上部における平面状
２０　シールド掘削機
２１　シールド筒
２２　隔壁
２３　フード部
２４　テール部
２５　シールド筒等の下部における小曲率のほぼ円弧形
２６　シールド筒等の上部における大曲率のほぼ円弧形
２７　回転駆動部
３０　平行クランク運動機構
３５　カッタヘッド
３９　掘削土砂のチャンバ
４０　排土装置
４３　推進ジャッキ
４４　セグメント[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a shield tunnel with a low earth covering, which is built on the seabed or under a riverbed and is used as a road, for example, and a shield excavator for excavating the tunnel.
[0002]
[Prior art]
As a technique for creating a tunnel such as a road tunnel under the seabed or under the riverbed, there have conventionally been a submerging method and a shield method.
[0003]
In the submerging method, the seabed or riverbed is dug from the sea or river, and a plurality of reinforced concrete boxes having a required cross section (often a rectangular cross section) are laid there. Then, the reinforced concrete box is backfilled with earth and sand, and the surrounding area is covered with chestnut stone.
[0004]
In this submerging method, the tunnel is installed at a shallow place under the seabed or riverbed. Therefore, when the use is a road tunnel, the road alignment can be shortened as compared with a shield tunnel.
[0005]
The shield method has an advantage that the construction work of the tunnel is performed underground, so that the sea area and the river area are not polluted and the ecosystem is not destroyed.
[0006]
[Problems to be solved by the invention]
However, in the submersion method, since the tunnel is excavated from the sea or river, there is a risk that seawater or river water pollution will destroy the ecosystem of the sea or river.
[0007]
In addition, in the submerging method, since a rectangular cross section is often employed, it is necessary to increase the thickness of the member, and a large amount of material such as reinforcing steel and concrete is used.
[0008]
Furthermore, in the submerging method, if the tunnel has a circular cross section, the seabed or the riverbed will be excavated deeply, making excavation from the sea or river difficult, and the construction period will be long. Therefore, it is difficult to adopt a circular cross section that is advantageous for earth pressure and water pressure.
[0009]
On the other hand, when a circular cross section is employed in the shield method, it is necessary to increase the depth in the ground compared to the burial method in order to prevent the shield excavator and the lining segment from floating due to buoyancy. For this reason, in the use as a road tunnel, the shield tunnel has a deeper road alignment than the sunken tunnel, and the total length of the tunnel is longer.
[0010]
Furthermore, the shield method requires a certain amount of earth covering for stabilization of the face, and generally requires a larger earth covering than a submerged tunnel. Therefore, the road alignment becomes deep.
[0011]
Further, in recent years, tunnels having a vertically symmetrical cross section with a rectangular cross section or an elliptical cross section have been made by a shield method. Such a shield tunnel is flatter than a circular cross section, so that the earth covering can be reduced. However, it is necessary to fill the lower part of the road with earth and sand or to fill it with concrete to counter buoyancy. As a result, the space of the tunnel is reduced, so that it is difficult to secure an evacuation passage or an emergency vehicle passage.
[0012]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and aims to make use of the advantages of the shield method, and is strong against water pressure, earth pressure, and buoyancy, and is used for a road tunnel as an earth covering. It is an object of the present invention to provide a shield tunnel with a low earth covering, which can reduce the size of the vehicle and can secure an evacuation passage and an emergency vehicle passage.
[0013]
Another object of the present invention is to provide a shield excavator capable of excavating the shield tunnel accurately.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, in the shield tunnel of the present invention, the lower portion of the tunnel section is formed in a substantially arc shape 2, 13, 17 having a small curvature, and the upper portion is formed in a circular or parabolic shape having a straight or large curvature. .
[0015]
Further, in order to achieve the above object, in the shield excavator of the present invention, a lower part of a section perpendicular to the axial direction of the shield cylinder 21, the partition wall 22, the hood part 23 and the tail part 24 is formed into a substantially circular arc 25 having a small curvature, The upper part is formed in a straight line or a substantially arcuate shape 26 having a large curvature, a parabolic shape, and the cutter head 35 is formed in a shape approximate to the right-angle cross-sectional shape of the shield cylinder 21, the partition wall 22, the hood part 23 and the tail part 24, The cutter head 35 is connected to the rotation drive unit 27 via the parallel crank movement mechanism 30.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
Embodiment 1
FIG. 1 is a sectional view showing Embodiment 1 of the shield tunnel of the present invention.
[0018]
In the shield tunnel 1 according to the first embodiment shown in FIG. 1, the lower portion of the tunnel section is formed in a substantially arc shape 2 having a small curvature, and the upper portion is formed in a substantially arc shape 3 having a large curvature.
[0019]
The outer shell of the shield tunnel 1 is constructed by connecting segments 4 formed into shapes conforming to the lower and upper portions of the tunnel cross section in the circumferential direction and the axial direction of the tunnel, respectively.
[0020]
The subgrade 5 in the shield tunnel 1 is formed by backfilling the excavated earth and sand alone, or the solidified soil obtained by mixing the excavated earth and sand with a solidifying material such as cement, or the fluidized soil.
[0021]
A subgrade concrete 6 is cast on the upper surface of the subgrade 5 via a connecting member 7 for reinforcing the tunnel.
[0022]
Furthermore, below the roadbed concrete 6, the central part of the roadbed 5 is partitioned by a column wall 8 provided on both sides, and a girder member 8 'provided above between the column walls 8 on both sides, and the evacuation passage 9 or An emergency vehicle passage is secured, and an evacuation passage floor 10 is formed below the evacuation passage 9.
[0023]
Further, a pavement portion 11 is laid on the upper surface of the roadbed concrete 6.
[0024]
A road 12 is secured above the pavement 11 in the shield tunnel 1.
[0025]
In FIG. 1, reference numeral 12 'denotes a vehicle construction limit, and reference numeral D denotes an earth covering between the water bottom and the top surface of the shield tunnel.
[0026]
In the shield tunnel 1 according to the first embodiment, since the lower portion of the tunnel section is formed in a substantially circular arc shape 2 having a small curvature, the strength can be increased with respect to earth pressure and water pressure. In addition, the evacuation passage 9 and the emergency vehicle passage can be secured below the roadbed concrete 6. Further, the lower part of the shield tunnel 1 is buried with the reclaimed earth and sand to reclaim the subgrade 5 to increase the weight of the tunnel, counter the buoyancy applied to the tunnel, and stabilize the tunnel. .
[0027]
Next, FIG. 2 is a diagram showing a comparison between the shield tunnel 1 according to the first embodiment of the present invention and the shield tunnel 19 having a circular cross section when the earth covering is the same. Corresponding members are indicated by similar reference numerals. FIG. 3 is a diagram comparing the relationship between the vertical linear depth of both shield tunnels shown in FIG. 2 and the road length at the approach portion of the tunnel.
[0028]
As shown in FIG. 2, when the shield tunnel 1 of the first embodiment of the present invention and the shield tunnel 19 having a circular cross section have the same earth covering D as shown in FIG. A difference H is generated between the shield tunnel 19 having a circular cross section and the depth direction of the vertical alignment. This difference H causes a difference 2L in road length at the approach portion of the tunnel. The road length difference 2L is obtained by the following equation.
(Equation 1)

Here, Θ is the road gradient from the ground to the approach part of the tunnel.
[0029]
According to the shield tunnel 1 of the first embodiment of the present invention, the length of the road can be reduced by 2 L as compared with the shield tunnel 19 having a circular cross section. Therefore, it is possible to save the equipment and materials for constructing the tunnel and shorten the construction period.
[0030]
Further, according to the shield tunnel 1 of the first embodiment, since the tunnel construction work is performed underground, the advantage of the shield construction method that the pollution of the sea area and the river area can be eliminated can be utilized as it is.
[0031]
Embodiment 2
Next, FIG. 4 is a sectional view showing Embodiment 2 of the shield tunnel of the present invention.
[0032]
Shield tunnel of Example 2 shown in FIG. 4, is formed in an arc shape 13 of the small curvature of radius R ₁ of the lower portion of the tunnel cross section centered at O _1, the intermediate portion is formed in a rectangular 14, an upper It is formed in a large curvature arc 15 having a radius R ₂ (R ₂ > R ₁ ) centered on O ₂ .
[0033]
The subgrade 5 is made by reusing backfill soil.
[0034]
In addition, in FIG. 4, the code | symbol 16 shows a roadbed.
[0035]
The shield tunnel according to the first embodiment is different from the shield tunnel according to the first embodiment except that an intermediate portion of the rectangle 14 is interposed between the upper and lower portions of the tunnel section to increase the height of the entire tunnel. And the operation is also the same.
[0036]
Embodiment 3
Next, FIG. 5 is a sectional view showing Embodiment 3 of the shield tunnel of the present invention.
[0037]
In the shield tunnel of the third embodiment shown in FIG. 5, the lower portion of the tunnel section is formed in a substantially circular arc shape 17 having a small curvature, and the upper portion is formed in a substantially planar shape 18.
[0038]
The subgrade 5 is formed by backfilling excavated earth and sand.
[0039]
In the shield tunnel according to the third embodiment, the upper portion of the tunnel cross section is formed in a plane shape 18. However, when the covering load is small, there is no problem in strength.
[0040]
The other configuration of the shield tunnel of the third embodiment is the same as that of the shield tunnel 1 of the first embodiment, and the operation is the same as that of the shield tunnel 1 of the first embodiment.
[0041]
In the shield tunnel according to the present invention, the shape of the upper portion of the cross section of the tunnel is substantially arc-shaped 3, 15 having a large curvature in FIGS. 1 and 4, but may be parabolic or shown in FIG. As described above, the shape may be a straight line, and may be within these ranges.
[0042]
Embodiment 4
6 to 8 show an embodiment of a shield excavator for excavating a shield tunnel according to the first embodiment of the present invention. FIG. 6 is a longitudinal side view, FIG. 7 is a front view, and FIG. Is a rear view.
[0043]
The shield excavator 20 of the embodiment shown in FIGS. 6 to 8 includes a shield cylinder 21, a partition wall 22, a hood section 23, a tail section 24, a rotary drive section 27 for a cutter head, and a parallel crank movement mechanism 30. , A cutter head 35, a chamber 39 for excavated earth and sand, an earth discharging device 40, a propulsion jack 43, and the like.
[0044]
The shield cylinder 21, the partition wall 22, the hood section 23, and the tail section 24 are formed such that a lower portion of a section perpendicular to the axial direction of the shield excavator 1 has a substantially circular arc 25 having a small curvature, and an upper portion has a large curvature. Is formed in a substantially arc shape 26.
[0045]
The rotary drive unit 27 for the cutter head has a drive motor 28 and a pinion 29 connected to the drive motor 28, as shown in FIG.
[0046]
The parallel crank movement mechanism 30 for the cutter head includes an internal gear 31 meshed with the pinion 29, a rotating body 32 formed integrally with the internal gear 31 and rotatably supported by the partition 22. It has an eccentric distance e with respect to the center of the rotating body 32 and an eccentric shaft 33 provided eccentrically.
[0047]
In this embodiment, five sets of the rotation drive unit 27 and the parallel crank movement mechanism 30 are arranged at a required interval from the rotation drive unit 27 and the parallel crank movement mechanism 30. The cutter head 35 is configured to cooperate to perform a parallel crank movement.
[0048]
At the center of the rotating body 32, a mud material inlet 34 is provided from inside the machine toward the chamber 39.
[0049]
The cutter head 35 has a cutter frame 36 and a plurality of cutter bits 37 implanted in the cutter frame 36. As can be seen from FIG. 5, the cutter frame 36 is formed in an approximate shape to the shield cylinder 21, the partition 22, the hood 23, and the tail 24. As for the cutter bits 37, the outline of the bit string is shown by a virtual line in FIG. 4, and the arrangement of the individual cutter bits is omitted.
[0050]
A plurality of stirring blades 38 are provided on the surface of the cutter frame 36 on the side of the chamber 39.
[0051]
The chamber 39 is formed in a space surrounded by the partition wall 22, the hood section 23, and the cutter head 35.
[0052]
In this embodiment, a screw conveyor is used as the earth discharging device 40. The earth discharging device 40 has a driving unit 41 and an earth discharging port 42, and is installed with an entrance portion facing the chamber 39.
[0053]
A plurality of the propulsion jacks 43 are provided inside the shield cylinder 21 at predetermined intervals in the circumferential direction.
[0054]
In the shield cylinder 20 in this embodiment, when a plurality of sets of rotary drive units 27 are driven simultaneously and in the same direction in the ground, the parallel crank motion mechanism 30 connected to each rotary drive unit 27 interlocks, The set of parallel crank motion mechanisms 30 causes the cutter head 35 to perform parallel crank motion.
[0055]
As the cutter head 35 performs the parallel crank movement, the cutting face is excavated by the cutter bit array 37, and the excavated earth and sand is taken into the chamber 39.
[0056]
As described above, the excavated earth and sand taken into the chamber 39 is injected with the excavated earth and soil from the earth and soil injection port 34, and the excavated earth and the earth and soil are stirred by the stirring blade 38 provided on the cutter frame 36. Thus, earth and sand having plastic fluidity is created.
[0057]
Then, the earth discharging device 40 is driven along with the excavation, and the earth and sand in the chamber 39 is taken into the earth discharging device 40 while preventing collapse of the face, and is discharged to the rear of the shield excavator 20 through the earth discharging port 42. You.
[0058]
Also, the segment 44 is assembled at the rear part in the shield excavator 20.
[0059]
After discharging the earth and sand in the chamber 39 and assembling the segments 44 as described above, a plurality of propulsion jacks 43 are simultaneously extended, and the reaction force is applied to the segments 44 to propel the entire shield excavator 20.
[0060]
Then, each propulsion jack 43 is contracted, and the segment 44 is assembled again at the rear of the shield excavator 20.
[0061]
The above operations are repeated to excavate the shield tunnel.
[0062]
According to the shield excavator 20 described above, the lower part of the section perpendicular to the axial direction of the shield cylinder 21, the partition wall 22, the hood part 23, and the tail part 24 is formed in a substantially circular arc 25 with a small curvature, and the upper part is a large curvature. And the cutter head 35 is formed in a shape approximate to the right-angle cross-section of the shield cylinder 21, the partition wall 22, the hood portion 23 and the tail portion 24, and the cutter head 35 is formed into a parallel crank movement mechanism 30. Therefore, the shield tunnel 1 of the first embodiment shown in FIG. 1 can be accurately excavated.
[0063]
In a shield excavator for excavating the shield tunnel according to the second embodiment shown in FIG. 4 and the shield tunnel according to the third embodiment shown in FIG. 5, the shield cylinder 21, the partition wall 22, the hood portion 23, and the tail portion 24 should be excavated, respectively. The cutter head 35 is formed into a shape corresponding to the tunnel cross section, and the cutter head 35 is formed into a shape similar to the tunnel cross section.
[0064]
【The invention's effect】
In the above-described shield tunnel of the present invention, since the lower portion of the tunnel section is formed in a substantially circular arc shape 2, 13, 17 having a small curvature, there is an effect that the strength against water pressure and earth pressure can be increased, and the inside of the tunnel is improved. There is an effect that the weight of the tunnel can be increased by embedding earth and sand in the lower part of the tunnel to counter the buoyancy applied to the tunnel and stabilize the tunnel. In the use as a road tunnel, the evacuation passage 9 or the like is provided in the lower part of the tunnel. It has the effect of securing an emergency vehicle passage, and furthermore, the upper part of the tunnel section is formed into a substantially circular arc shape 3, 15 with a large curvature and a substantially planar shape 18, so that in the case of a road tunnel, a shield having a circular cross section is used. Compared to tunnels, it has the effect of shortening the length of roads, which in turn can save equipment and materials for tunnel construction, and can also shorten the construction period. Since the construction work, being able to eliminate the pollution of waters and river area, also has the advantage to be taking advantage of as it is the effect of the shield method.
[0065]
Further, in the shield excavator of the present invention, the lower part of the section perpendicular to the axial direction of the shield cylinder 21, the partition wall 22, the hood part 23 and the tail part 24 is formed in a substantially circular arc shape 25 with a small curvature, and the upper part is straight or curved. The cutter head 35 is formed in a substantially circular arc shape 26 having a large curvature, in a parabolic shape, and the cutter head 35 is formed in an approximate shape to the right-angle cross-sectional shape of the shield cylinder 21, the partition wall 22, the hood portion 23 and the tail portion 24. Since it is connected to the rotary drive unit 27 via the parallel crank motion mechanism 30, the shield tunnel according to the present invention can be excavated accurately.
[Brief description of the drawings]
FIG. 1 is a sectional view showing Embodiment 1 of a shield tunnel of the present invention.
FIG. 2 is a diagram showing a comparison of the depth of the vertical alignment of the shield tunnel of Example 1 of the present invention and a shield tunnel of a circular cross section when the earth covering is the same.
FIG. 3 is a diagram showing a comparison between a vertical linear depth of both shield tunnels shown in FIG. 2 and a road extension at an approach portion of the tunnel;
FIG. 4 is a sectional view showing Embodiment 2 of the shield tunnel of the present invention.
FIG. 5 is a sectional view showing Embodiment 3 of the shield tunnel of the present invention.
FIG. 6 is a longitudinal sectional side view showing one embodiment of the shield excavator of the present invention.
FIG. 7 is a front view of the shield excavator.
FIG. 8 is a rear view of the shield excavator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shield tunnel 2 Approximately arc shape with a small curvature at the lower part of tunnel section 3 Approximately arc shape with a large curvature at the upper part of tunnel section 4 Segment 5 Subgrade 6 Subgrade concrete 7 Connecting member 8 Column wall 8 'Beam material 9 Evacuation passage 12 Road D Overburden 13 Almost arc-shaped with small curvature at the lower part of tunnel section 15 Almost arc-shaped with large curvature at the upper part of tunnel section 16 Subbase 17 Almost arc-shaped with small curvature at the lower part of tunnel section 18 Planar 20 at upper part Shield excavator 21 Shield cylinder 22 Partition wall 23 Hood part 24 Tail part 25 Almost arcuate shape with small curvature at the lower part of shield cylinder etc. Almost arcuate shape with large curvature at the upper part of shield cylinder etc. 27 Rotary drive Part 30 parallel crank motion mechanism 35 cutter head 39 excavated earth and sand chamber 40 earth removal device 43 propulsion Yakki 44 segment

Claims (2)

A shield characterized in that the lower part of the tunnel section is formed in a substantially circular arc shape (2), (13), (17) with a small curvature, and the upper part is formed in a linear or large circular arc shape or parabolic shape. tunnel. The lower part of the section perpendicular to the axial direction of the shield cylinder (21), the partition (22), the hood part (23) and the tail part (24) is formed in a substantially circular arc shape (25) with a small curvature, and the upper part is straight or curved. It is formed in a substantially arc shape (26) with a large curvature, in a parabolic shape,
A cutter head (35) is formed in a shape similar to a right-angle cross-sectional shape of the shield tube (21), the partition wall (22), the hood portion (23) and the tail portion (24),
Said cutter head (35) connected to a rotary drive (27) via a parallel crank movement mechanism (30);
A shielded excavator, characterized in that:

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