JPH0681584A - Large section excavating construction method and shielded excavator - Google Patents

Abstract

PURPOSE:To easily excavate a tunnel having a large section by doughnut ring- shapedly excavating a natural ground in a state where it is contained in a shielded body using the circular shielded machine of the doughnut ring-shaped shielded body. CONSTITUTION:A doughnut ring-shaped shielded body 10 forming a skin plate on its peripheral face is provided along the outer peripheral edge of a planned tunnel. Next, as circular shielded machines 16 attached to front ends are driven all together, shielded jacks 30 are extendedly driven. The circular shielded machine 16 takes excavated earth and sand into a shielded chamber by rotatingly driving a cutter head. A soft-type jack is simultaneously driven, and circular skin plates 18 execute oscillating motion all together from side to side along the direction of the peripheral edge of the doughnut ring. The nonexcavated domain of the circular shielded machine 16 is then decreased to facilitate excavation, and in a fan-shaped zone between the adjacent circular shielded machines 16, the excavation is executed by an excavating bit directly buried in the shielded body 10 to make the doughnut ring-shaped excavation possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-section excavation method and a shield excavator, and more particularly to an excavation method and a shield excavator capable of realizing large-section tunnel excavation with an excavation diameter exceeding 15 m.

[0002]

2. Description of the Related Art Conventionally, when performing shield excavation on a tunnel having a large cross section, the diameter of the shield excavator must be increased.
Or multi-face (MF) with cross section such as eyebrows
Alternatively, it is performed by using a multiple-type (DOT) shield excavator. In any case, a shield excavator of a size that matches the diameter and shape of the tunnel to be excavated was used, and the structure was such that so-called full-section excavation was performed in which the size of the excavator itself matches the size of the tunnel to be constructed. .

[0003]

However, there is a limit to increasing the size of the shield excavator itself, and although a shield excavator having a diameter of 10 m or more is actually manufactured and used, it exceeds the limit. There was a problem not only in manufacturing an excavator of a size, but also in constructing and using it from the viewpoint of the balance of ground pressure and earth pressure. Therefore, it has been practically impossible to perform excavation with a tunnel diameter exceeding 15 m by a shield excavator.

In view of the above conventional problems, the present invention aims to provide a large-section excavation method and a shield excavator capable of easily excavating a large-section tunnel having an equivalent diameter of more than 15 m. And

[0005]

In order to achieve the above object, a large cross-section excavation method according to the present invention is a donut ring-shaped tubular excavation along a peripheral circle of a tunnel to be excavated. A lining was formed to form the outer shell of the tunnel, and then the ground core portion remaining inside was excavated by a general construction machine.

The shield excavator for large-section excavation according to the present invention has a donut ring-shaped shield body having skin plates formed on the inner and outer peripheral surfaces along the outer peripheral edge of the tunnel to be excavated, and the shield. It is composed of a plurality of circular shield machines arranged in parallel along the ring direction of the main body and attached via the center folding mechanism, and enables donut ring-shaped excavation in a state in which the ground is included in the shield main body. It is a thing.

[0007]

According to the above construction, while the shield main body is being excavated, the circular shield excavator arranged on the front end face portion thereof is pivotally moved while the cutter head is rotationally driven. A part of the ground is excavated in a donut ring shape. At this time, since the ground is taken into the donut-shaped cylindrical portion without being disturbed, the primary lining can be performed while excavating in balance with the ground pressure and the earth pressure via the ground core. After that,
The core ground in the donut shape may be excavated at regular intervals with a general construction machine, and then secondary lining may be performed. As a result, tunnel excavation of a large cross section can be realized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of a large-section excavation method and a shield excavator according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the structure of a shield excavator for large-section excavation according to an embodiment. The shield excavator for large-section excavation of the embodiment is for performing tunnel excavation with an arch-shaped section, for example, maximum width B = 22600 mm and maximum height H =.
An arch tunnel with a size of 16200 mm is targeted for excavation. For such tunnel excavation, as illustrated, the shield excavator according to the embodiment includes a donut ring-shaped shield body 10 along the entire outer periphery of the cross-sectional shape of the arch tunnel to be excavated. This is a hollow cylindrical structure which is composed of a pair of an inner cylinder 12 and an outer cylinder 14 which form a skin plate, and in which the equivalent diameter difference between both cylinders is set to 2500 mm, for example. As a result, a donut ring body having an excavation width of W = 2500 mm is formed, and the donut ring is excavated along the inner peripheral surface of the arch tunnel by advancing the ring tip surface as a propulsion surface.

A plurality of circular shield machines 16 having a diameter (D = 2500 mm) corresponding to the excavation width dimension W are arranged along the ring direction on the front end face of the donut ring-shaped shield body 10. There is. In this embodiment, 20 circular shield machines 16 are arranged so as to be arranged substantially densely side by side in the circumferential direction, and a skin plate 18 having a circular cross section is attached from the tip surface of the donut ring shield body 10 in a protruding state in the digging direction. .

As shown in the sectional structure of FIG. 3, each circular shield excavator 16 is provided with a circular skin plate 18 protruding from the front end face of the donut ring shield body 10 and swingably attached thereto. A plurality of center folding jacks 20 mounted between the ring shield body 10 and the ring shield body 10 are driven to swing. A bulkhead 22 is attached to a central portion of the circular skin plate 18, and a cutter head 24 facing the face is attached to the bulkhead 22 so as to be rotatable, and is rotated by a hydraulic motor 26 provided on the back surface of the bulkhead 22. ing. The shield chamber 23 formed between the bulkhead 22 and the cutter head 24 faces a screw conveyor 28 as an earth discharging device to discharge the earth and sand taken into the chamber 23. Although the excavation is performed by the rotation of the cutter head 24, a shield jack 30 for pressing and propelling the donut ring shield main body 10 in the excavation direction is provided behind each circular shield machine 16, and is constructed behind the donut ring shield main body 10. The propulsive force is generated between the segment and the segment. The shield jack 30 is arranged rearward with the segment 32 constructed by the primary lining as a support surface, but as shown in FIG. 2 (2), the donut ring shield body 10 is appropriately spaced from the inner peripheral edge and the outer peripheral edge. The donut ring shield body 10 is appropriately arranged in the propulsion direction.

The circular shield machine 16 excavates the ground ahead of the donut ring shield body 10, but a fan-shaped dead zone is formed on the front end face of the donut ring shield body 10 that does not become the excavation area of the circular shield machine 16. To be done. In order to excavate the natural ground facing the dead zone, the middle-breaking jack 20 is operated and driven to expand the excavation area by the circular shield machine 16, and the circular shield machine 16 cannot be reached by the swinging operation. The range is such that the cutter bit provided on the front end face of the donut ring shield body 10 excavates the donut ring shield body 10 by the digging force.

In the shield excavator for large-section excavation having such a structure, the donut ring shield body 10 is arranged along the outer peripheral edge of the planned tunnel, and the circular shield machines 16 attached to the front end face thereof are driven all at once. Meanwhile, the shield jack 30 is extendedly driven. At this time, the circular shield machine 16 takes in the excavated earth and sand into the shield chamber 23 by rotationally driving the cutter head 24. At the same time, the center folding jack 20 is driven to simultaneously move the circular skin plate 18 to the left and right along the circumferential direction of the ring. Perform a swing motion. This reduces the unexcavated area of the circular shield machine 16 and facilitates excavation. Then, in the fan-shaped zone between the adjacent circular shield machines 16, excavation is performed by the excavation bit directly embedded in the donut ring shield main body 10, and the donut ring excavation becomes possible as a whole.

In the state of excavation by such a shield excavator, ring-shaped excavation is performed in a state where a rock core is present inside the donut ring shield body 10.
Therefore, even when the equivalent diameter of the excavation tunnel is large, unlike the case of full-section excavation, the ground pressure can be advanced while being sufficiently supported while being balanced in the ground core portion. After constructing a segment at the rear by this donut ring-shaped excavation and making the primary lining, the donut shape inside, that is, the natural core part, is set at a certain distance from the excavation tip, and the general construction machine such as a shovel car The secondary lining is carried out while excavating.

According to the above-described embodiment, the tunnel is excavated in a donut shape by the shield excavator to form a primary lining, and then the inside of the donut-shaped tunnel outer shell is subsequently excavated by a general construction machine. Therefore, it is possible to easily realize tunnel excavation of large cross section, and especially since it can be constructed without excavating all cross section, tunnel excavation with well balanced ground pressure and earth pressure is possible. It becomes.

The shield excavator can be applied not only to side shaft excavation but also to vertical shaft excavation.

[0017]

As described above, according to the present invention, there is provided a donut ring-shaped shield body having skin plates formed on the inner and outer peripheral surfaces along the outer peripheral edge of the tunnel to be excavated, and the ring direction of the shield body. By means of an excavator composed of a plurality of circular shield machines that are arranged in parallel along with each other and attached via a center-folding mechanism, it is possible to excavate a donut ring in a state in which the ground is included in the shield body. Therefore, it is possible to excavate a large section having an extremely large tunnel section with a shield, and it is possible to obtain an excellent effect that a large section tunnel having an equivalent diameter of more than 15 m can be easily excavated.

[Brief description of drawings]

FIG. 1 is a front view and a cross-sectional view of a shield excavator for large-section excavation according to an embodiment.

FIG. 2 is a plan view of the shield excavator and an arrangement configuration diagram of a shield jack.

FIG. 3 is a front view and a sectional view of a circular shield machine.

[Explanation of symbols]

 10 Donut Ring Shield Body 12 Inner Cylinder 14 Outer Cylinder 16 Circular Shield Machine 18 Circular Skin Plate 20 Middle Break Jack 22 Bulkhead 24 Cutter Head 26 Hydraulic Motor 28 Screw Conveyor 30 Shield Jack

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiyasu Yoshikawa 4-13-13 Akasaka, Minato-ku, Tokyo Kyowa Exio Co., Ltd. (72) Inventor Takashi Nakamura 4-13-13 Akasaka, Minato-ku, Tokyo Kyowa Exio (72) Inventor Mitsuaki Iwata 4-13-13 Akasaka, Minato-ku, Tokyo Kyowa Exio Co., Ltd.

Claims (2)

[Claims] 1. A lining for forming a donut ring-shaped tunnel outer shell by making a donut ring-shaped cylindrical excavation along the outer circumference of the tunnel to be excavated, and then the ground core portion remaining inside is generally used. A step section excavation method characterized by excavating with a construction machine. 2. A donut ring-shaped shield body having skin plates formed on the inner and outer circumferential surfaces along the outer peripheral edge of the tunnel to be excavated, and the doughnut-shaped shield body arranged in parallel along the ring direction of the shield body. A shield excavator for large-section excavation, which is configured by a plurality of circular shield machines attached via a folding mechanism, and which enables excavation of a donut ring in a state where the ground is included in the shield body.