JPH0791946B2 - Tunnel and tunnel construction method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tunnel having a seismic reduction structure and a method for constructing the tunnel.

[Conventional technology]

In recent years, due to the remarkable progress of the shield construction method, a tunnel with a large diameter of 10 meters or more has been constructed.

As a shield construction method for constructing such a large-diameter tunnel, conventionally, while excavating the ground with a shield excavator, assembling a segment behind the tail part of the shield excavator along with the excavation and the excavated wall surface and The lining material such as mortar is poured into the voids between the segments from the inside of the tunnel and solidifies to solidify the tunnel lining by the segment and the excavated ground, and the backing material prevents the ground from collapsing. Groundwater is prevented from entering the tunnel from the ground.

[Problems to be Solved by the Invention]

However, in Japan, which is one of the most earthquake-prone countries in the world, it is natural that tunnels must have a high earthquake-resistant structure to ensure safety. However, when a tunnel is built over a layer of different geology from the land to the seabed, such as a seabed tunnel, an earthquake will occur because When it occurs, a large difference occurs in the deformation amount of different formations, and the stress corresponding to the difference in the deformation amount acts on the tunnel structure at the boundary, which may cause the tunnel to be destroyed. Have.

In addition, since the backfill material injected between the excavated wall surface and the segment is cement-based, cracks are likely to occur due to earthquake motion, etc., and water leakage will occur in the tunnel.

An object of the present invention is to provide a tunnel and a method of constructing a tunnel in which such problems are solved.

[Means for Solving the Problems]

In order to achieve the above object, the tunnel structure of the present invention comprises
A vibration energy absorption layer that is softer, more viscous, and elastic than the ground is provided between the excavated ground and the outer circumferential surface of the tunnel lining.As such a vibration energy absorption layer, asphalt emulsion and cement, and if necessary Accordingly, a layer in which a thickening agent such as bentonite or a polymer is mixed and solidified (hereinafter referred to as room temperature water-curable asphalt) is desirable.

In addition, as a method of constructing such a tunnel, shield excavation is performed when excavating the ground with a shield excavator and assembling segments behind the tail portion of the shield excavator according to the excavation to form a tunnel lining. A backing material of room temperature curing asphalt is injected into the gap between the excavated ground and the outer surface of the lining from the tail end of the machine tailor or in an appropriate place on the segment, and the vibration energy absorption layer softer than the ground by solidifying the backing material. Is formed.

[Action]

According to the structure of the tunnel configured as described above, when an earthquake occurs, the ground is displaced, but the vibration energy absorption layer is compressed according to the amount of fluctuation, reducing the earthquake motion that acts on the tunnel lining. Reduces the stress generated in the tunnel lining.

Such a seismic reduction effect is effectively performed in the case of a tunnel constructed over layers of different geology, such as an undersea tunnel, and even if the amount of displacement of both layers is different, it will extend across both layers. The vibration energy absorption layers provided in series absorb the vibration energy from both formations so that they are averaged, and evenly reduce the stress generated along the length of the tunnel lining to locally reduce the stress at the boundary of formations. It eliminates the occurrence of specific stress.

In addition, the same effect can be obtained even in a place where the ground changes suddenly between the upper part and the lower part of the tunnel cross section.

In order to form a vibration energy absorption layer that is softer than such ground on the outer circumference of the tunnel, when constructing the tunnel, the excavated ground and the lining outer surface from the appropriate position of the tail end or segment of the shield excavator. It can be easily formed by injecting a backfill material consisting of room-temperature underwater-curing asphalt into the gap between and and solidifying the backfill material. And the backfilling material is injected into this space to form a vibration energy absorption layer having a uniform thickness on the outer circumference of the tunnel lining.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings. (1) is a ground on the ground having a high rigidity, and (2) is a soft ground on the seabed, which is composed of a sedimentary layer having a low rigidity. .

(3) is an undersea tunnel constructed from the rigid ground (1) on land to the soft ground (2) on the seabed, and the gap between the outer circumference of the lining (4) and the ground (1) (2). The vibration energy absorption layer (5) having a desired thickness is formed in the tunnel (3).
Is formed with a substantially uniform thickness over the entire length thereof.

This vibration energy absorption layer (5) is the formation (1) (2)
The vibration energy absorbing layer is made of a material having a softer viscosity and elasticity than that of the asphalt emulsion and cement, and if necessary, a thickening agent such as bentonite or polymer is mixed in a room temperature underwater curing type. A solidified layer of asphalt is preferred.

(6) is a plurality of spacer members arranged at predetermined intervals in the circumferential direction and the length direction at intervals between the excavated ground of the tunnel and the outer peripheral surface of the tunnel lining. ) Is maintained and the amount of ground displacement during an earthquake is reduced to reduce the amount transmitted to the tunnel.

The spacer member (6) includes a pair of front and rear screw cylinders (4b) threaded between the inner and outer peripheral surfaces of a segment (4a) forming a tunnel lining, and a spring (not shown) installed in the screw cylinder (4b). The pin (4c) connected to the tip of the spring (4c) and constantly pressed by the spring, and the contact plate (4d) fixed between the pins (4c) and (4c) in the erected state. Four
The contact plate (4d) is pressed against the inner peripheral wall surface of the excavated ground by screwing the screw cylinder (4b) from the inside of (a).

To construct such a tunnel, for example, a shield excavator (7) is used to excavate from a rigid ground (1) on land to a soft ground (2) on the seabed. While excavating the ground by (7), segments (4a) (4
a) ・ ・ ・ (4a) is assembled into an annular shape, the assembled segment receives the reaction force and the shield excavator (7) is propelled and excavated, and the segment assembled by this excavation is from the tail to the excavated ground side. Exposed to. In this way, the assembly of the segment (4a) and the excavation of the shield excavator (7) are repeated to form the tunnel lining (4) by the assembled segment on the excavated ground.

At this time, due to the forward movement of the shield excavator (7), a gap is created between the outer peripheral surface of the segment (4a) located on the excavation ground side from the tail portion and the excavation ground, so that the segment (4a) should be installed on the segment (4a). The contact plate (4d) is pressed against the inner peripheral wall surface of the excavated ground by screwing the plurality of screw cylinders (4b) from the inside of the segment (4a), and the outer peripheral surface of the segment (4a) and the excavated ground. The segment (4a) assembled in an annular shape is fixed with a predetermined space (8) provided therebetween.

Then, as a backfill material, room temperature water is used as a backfill material from the injection hole (9) (9) that has been previously provided in a proper place in the segment (4a) so as to extend between the inner and outer peripheral surfaces to the space (8) with the excavated ground. Inject hardening asphalt (22).

This room-temperature water-curable asphalt (22) is an asphalt emulsion (1 that has asphalt dispersed in water containing an emulsifier.
Cement (14) is mixed with 0), and a super absorbent polymer is added to this as a thickener (17) to solidify. After solidification, it forms a layer with soft elasticity and moderate viscosity. To do.

As a means for forming such a layer, as shown in FIG. 2, the required amount of asphalt emulsion (10) from the storage tank (11) and cement (14) from the storage tank (13) and the mixing tank, respectively. The asphalt emulsion (10) and the cement (14) are mixed by supplying to (12) and rotating a stirring blade (15) arranged in the tank (12), and after uniformly mixing, the injection hole ( 9) The pressure pump (16) is sent to the pipe (23) toward (9). On the other hand, the required amount of thickener (17) is taken out from the storage tank (18), and the pressure pump (1
It is pressure-fed by 9) and is fed into the pipe (23) at the position of the Y-tube (20) and mixed with the mixture of asphalt emulsion (10) and cement (14). Furthermore, means for uniformly mixing with a mixing accelerator (21) and forcing the mixture from the injection holes (9) (9) to the space (8) between the segment and the excavated ground can be employed.

The vibration energy absorption layer (5) is composed of the segments (4
An injection hole opened toward the gap (8) at the rear end of the tail part of the shield excavator, in addition to being formed by supplying the gap (8) from the injection hole (9) provided in a). (Not shown) may be provided, and the backfill material may be pressure-fed from the injection hole to the gap portion (8).

The room temperature underwater hardening type asphalt (22) supplied to the space (8) between the outer peripheral surface of the tunnel lining (4) thus formed by the segment and the excavated ground is composed of the asphalt emulsion (10) and the cement (14). The reaction energy is gradually solidified to form the vibration energy absorption layer (5).

If the outer circumference of the tunnel lining (4) is entirely covered with such a vibration energy absorption layer (5), in the event of an earthquake, the rigid ground (1) and the soft ground (2) will be described.
It is possible to absorb the difference in the amount of displacement (strain) and to absorb the vibration energy and reduce the seismic motion transmitted to the tunnel.

In addition, the vibration energy absorption layer (5) is a rigid ground (1).
Is not limited to the tunnel provided between the soft ground (2) and the soft ground (2), and other than such a tunnel, for example, in a tunnel in the rigid ground (1) or a tunnel in the soft ground (2), or a tunnel cross section. Even in places where the ground changes suddenly above and below, it is possible to exert a seismic reduction effect against earthquakes.

〔The invention's effect〕

As described above, according to the tunnel structure of the present invention, since the vibration energy absorption layer which is softer, more viscous and elastic than the ground is provided between the excavated ground and the outer circumferential surface of the tunnel lining, an earthquake occurs. When the ground is displaced, the vibration energy absorption layer is compressed according to the amount of fluctuation, and the vibration acting on the tunnel lining can be dampened to reduce the stress generated in the tunnel lining. It can provide a safe tunnel, especially in the case of a tunnel built over different geological layers such as an undersea tunnel, even if the displacement amount of both geological layers is different. By absorbing the vibration energy from both formations on average by the vibration energy absorption layer provided in series over,
The stress generated over the length of the tunnel lining can be uniformly reduced to eliminate the local stress generation at the boundary of the stratum.

In addition, as a method of constructing such a tunnel, shield excavation is performed when excavating the ground with a shield excavator and assembling segments behind the tail portion of the shield excavator according to the excavation to form a tunnel lining. The room temperature water-curable asphalt backing material is injected into the gap between the excavated ground and the outer surface of the lining from the tail end of the machine or in an appropriate position on the segment, and the solidification of the backing material absorbs vibration energy that is softer than the ground. Since the layer is formed, it is possible to easily form the vibration energy absorption layer while constructing the tunnel.

As such a vibration energy absorption layer, by adopting a layer of room-temperature water-curable asphalt, it is possible to form a layer having appropriate elasticity and viscosity that can effectively reduce vibration. Therefore, since there is no crack, it is possible to prevent the groundwater from leaking into the tunnel. Furthermore, by interposing elastic spacer members at a plurality of places between the excavated ground and the outer surface of the tunnel lining. The vibration energy absorption layer having a uniform thickness can be formed on the outer circumference of the tunnel lining.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a simplified vertical sectional side view of a tunnel, and FIG. 2 is a vertical sectional side view of a state in which a tunnel is being built by a shield excavator, FIG. 3 and FIG. FIG. 2 is a vertical sectional front view taken along the lines AA and BB in FIG. (1) (2) ... Ground, (3) ... Tunnel, (4) ... Tunnel lining, (5) ... Vibration energy absorption layer, (6) ... Spacer member, (7) ... Shield excavator, (8) … Spacing, (10)… asphalt emulsion, (14)… cement.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Moriyoshi 1-9-10 Kiyota Nijo, Toyohira-ku, Sapporo-shi, Hokkaido (72) Inventor Mikio Takeuchi 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi, Osaka Okumura Group (72) Inventor Yoshiaki Iwada 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka City, Osaka Prefecture Okumura Group Inc. (72) Inventor Kenichiro Ohno 2-2 Matsuzaki-cho, Abeno-ku, Osaka City, Osaka Prefecture Co., Ltd. Okumura group

Claims (3)

[Claims] 1. A tunnel characterized in that a vibration energy absorption layer is provided between the excavated ground and the outer peripheral surface of the tunnel lining, and a solidified mixture of asphalt emulsion and cement is provided. 2. A tunnel characterized in that a vibration energy absorbing layer is provided between the excavated ground and the outer peripheral surface of the tunnel lining, and a solidified mixture of asphalt emulsion, cement and thickener is provided. 3. A method of constructing a tunnel, wherein a tunnel lining is formed by excavating the ground by a shield excavator and assembling segments behind the tail portion of the shield excavator according to the excavation. Inject a backing material consisting of asphalt emulsion and cement mixed normal temperature underwater curing type asphalt in the gap between the excavated ground and the outer surface of the lining from the appropriate position of the rear end or segment, and solidify the backing material to remove it from the ground. A method of constructing a tunnel characterized by forming a soft vibration energy absorption layer.