JPH02210194A - Shield machine and shield method - Google Patents

Abstract

PURPOSE:To enable effective utilization of the whole of an excavating section by a method wherein a slave shield is contained in a parent shield and a cutter is mounted to the front of the salve shield, an over cutter is expandably mounted to the outer peripheral part thereof, and the slave shield is positioned eccentrically. CONSTITUTION:A slave shield 3 having a cylindrical skin plate 5 is contained in a parent shield 2 having a cylindrical skin plate 4, and a cutter 10 provided expandably at its outer peripheral part with an over cutter 12 is mounted to the front of the slave shield. The slave shield 3 is mounted to a frame 6 slidable so that it can be positioned eccentrically to the parent shield 2. After a tunnel T is built by means of the parent shield 2, the axis of the slave shield 3 is positioned eccentrically to the axis of the parent shield 2. Further, a front partition wall 8 secured to the front end part of the slave shield 3 is separated away from the slave shield 3 through control effected from the interior of the slave shield 3, and the slave shield 3 is independently advanced.

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention relates to a shield machine used in the shield construction method, and is particularly applicable to tunnels where the diameter partially increases, such as in subway stations or sewer pipe connections. The present invention relates to a shielding machine and a shielding method suitable for use in forming the shield.

``Prior art'' Conventionally, shielding machines used to form tunnels with partially enlarged diameters, such as inside subway stations, have been designed to coaxially place a child shield inside a parent shield with a cylindrical outer shape. For example, when excavating a subway tunnel, after excavating a section of the station premises that has a larger diameter than the normal track section using both shields,
It is known to excavate a normal track section by advancing only the child shield.

"Problems to be Solved by the Invention" However, in the above-mentioned shield machine, the parent shield and the child shield are fixed coaxially, so even when forming a subway station premises, the main shield and the child shield are fixed in a coaxial manner. A large-diameter tunnel coaxial with the small-diameter tunnel must be excavated, and therefore a large-diameter tunnel that is larger than necessary must be excavated. In other words, when forming a station section on one side of a track section, an unnecessary excavation cross section with the same width as the station section must be formed on the opposite side of the station section, sandwiching the track section. There is a problem that the entire cross section cannot be used effectively, and unnecessary excavated cross sections must be backfilled, resulting in poor efficiency.

This invention was made in view of the above circumstances, and it is possible to effectively utilize the entire excavation cross section without forming unnecessary cross sections even when forming a tunnel whose diameter partially increases. The purpose is to provide shield machines and shield construction methods.

"Means for Solving the Problems" In the shield machine of the present invention, a child shield having a cylindrical skin plate having a smaller diameter than the skin plate of the parent shield is arranged inside a parent shield having a cylindrical skin plate. This shield machine is equipped with a cutter that forms an excavation cross section that is approximately the same as the cross section of the child shield at the front of the child shield, and a cutter that forms an excavation cross section that is approximately the same as the cross section of the child shield, and a cutter that has a diameter that is approximately the same as the diameter of the parent shield on the outer periphery of the cutter. An overcutter that protrudes in the radial direction up to 100 degrees is telescopically attached, and a slide mechanism is provided for making the child shield eccentric with respect to the parent shield.

Further, the shield construction method of the present invention is a shield construction method carried out using the above-mentioned shield machine, in which after forming a tunnel with a parent shield, a child shield is eccentrically placed with respect to the parent shield, and then this child shield is attached to the parent shield. By separating and independently starting the tunnel, a tunnel that is smaller in diameter and eccentric than the tunnel formed by the parent shield is successively formed.

"Operation" When forming a tunnel by the shield construction method using the shielding machine of the present invention, first, when forming a large diameter tunnel, the parent shield and the child shield are fixed coaxially, and an overcutter is used. With the cutter protruding and the diameter of the cutter extended to the same extent as the diameter of the parent shield, the entire shield machine is excavated while rotating the cutter. After forming a large-diameter tunnel in this way, when forming a small-diameter tunnel continuously from this large-diameter tunnel, by pulling in the over cutter, the diameter of the cutter can be made to be the same as the diameter of the child shield. By retracting and sliding the child shield in the horizontal direction using the slide mechanism, its axis is placed eccentrically with respect to the axis of the parent shield (9).After this, the cutter is rotated and the child shield is While holding the shield in place, the child shield moves forward independently of the parent shield.

``Embodiment'' An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

In these figures, the symbol 1 is an earth pressure type shield machine, and the symbol T is a tunnel formed by excavating the ground G with the shield machine 1.

The shield machine 1 is composed of a parent shield 2 and a child shield 3, and includes a cylindrical skin plate 4.
A cylindrical skin plate 5 having a smaller diameter than the skin plate 4 of this parent shield 2 is installed inside the parent shield 2 having a
A child shield 3 having the following characteristics is arranged.

This child shield 3 normally has its axis centered on the parent shield 2.
The child shield 3 is fixed on a pedestal 6 provided at the lower part of the parent shield 2 so as to be coaxial with the axis of the child shield 3, and the child shield 3 is slidably placed on the pedestal 6. Therefore, by moving it in the horizontal direction as necessary, its axis can be made eccentric to the axis of the parent shield 2.

A donut plate-shaped rear partition wall 7 is provided on the outer periphery of the rear end of the skin plate 5 of the child shield 3, and this rear partition wall 7 allows the rear end of the child shield 3 to be connected to the parent shield 5.
The child shield 3 is fixed to the inner surface of the skin plate 4, and the front end of the child shield 3 has front portions on both sides thereof (on the right and left sides of the child shield 3 in FIGS. 3 and 4). A partition wall 8.8 is provided, and the front end of the child shield 3 is inserted from behind the front partition wall 8 on the opposite side to the eccentric direction of the child shield 3 (front partition wall 8 on the right side in FIGS. 3 and 4). A front bulkhead 9 fixed to the parent shield 2 side is placed above and below the main shield 2 with a part of its front surface in contact with the rear surface of the front bulkhead 8 (see Fig. 1). There is.

A cutter IO for excavating the face G is provided at the front of the child shield 3. This cutter 10 is of a face plate type or a spoke type (spoke type in this embodiment), and is configured to excavate the face G by rotating around an axis, and the rotating shaft 11 is expandable and retractable in the axial direction. It is attached to the child shield 3 in this state, and normally its diameter is approximately the same as the diameter of the child shield 3. As shown in FIGS. 1 and 2, an overcutter 12 that protrudes in the radial direction and extends to a diameter comparable to the diameter of the parent shield 2 is telescopically attached to the outer periphery of the cutter IO. With this overcutter 12 protruding, it is possible to excavate a tunnel with a diameter as large as that of the parent shield 2.

As described above, the child shield 3 having the above configuration is disposed inside the skin plate 4 of the parent shield 2, and is integrally connected to the parent shield 2 by the rear partition wall 7, and the connection is released. It can move forward independently from the parent shield 2 along the axial direction.

Also, inside the skin plate 4 of the main shield 2 and behind it, there is a shield jack 1 for propelling the main shield 2 itself forward of the excavated tunnel T.
3 is provided, and furthermore, a peripheral wall T of the tunnel T after excavation is provided.
, is equipped with an erector device (not shown) for assembling the segment S.

Next, a procedure for forming a subway tunnel using the shield machine 1 having the above configuration will be explained.

First of all, when forming the tunnel T in the station area, the child peel 3 is placed coaxially within the parent shield 2, and these shields 2.3 are interconnected by the rear bulkhead 7 and integrated. The shield machine 1 in this state is set at the bottom of the tunnel T with the cutter 10 facing in the direction in which the tunnel T is to be excavated, and then the rotary shaft 11 of the cutter 10 is extended in the axial direction so that the cutter 10 is set at the bottom of the tunnel T. After protruding and extending the over cutter 12 of the cutter 10 to make the diameter of the cutter 10 approximately the same as the diameter of the parent shield 2, the entire shield machine 1 is advanced forward while rotating the cutter 10. As a result, face G is excavated. After digging a predetermined distance, the erector device on the main shield 2 side installs the segment S on the peripheral wall T of the tunnel T excavated by the shield machine 1 to temporarily line it, and then the main shield 2 By extending the shield jack 13 by taking a reaction force to the front end of the assembled segment S, the entire shield machine 1 is propelled forward.

In this way, by repeating the steps of excavating with the cutter 10, assembling the segments S, and advancing the shield machine 1, the entire shield machine 1 excavates a tunnel T with a length corresponding to the length of the station area. do.

In this way, after forming a large-diameter tunnel T that will become a station part, when forming a small-diameter tunnel that will become a track part continuously from this large-diameter tunnel T, first, the rear bulkhead 7
By removing the main shield 2 and the child shield 3, the connection between the parent shield 2 and the child shield 3 is released, and then by retracting the over cutter 12, the diameter of the cutter 10 is reduced to the same extent as the diameter of the child shield, and the rotating shaft 11 of the cutter 10 is After retracting and housing the cutter lO in the parent shield 2, the child shield 3 is
is moved in the horizontal direction (in the direction of the arrow in Figures 1 and 3) while sliding it on the pedestal 6 using a hydraulic jack or the like, and at the same time, the front bulkhead 8 on the left side in Figure 3 is moved as necessary. By penetrating the ground while jetting from the tip, the axial center of the child shield 3 is made eccentric with respect to the axial center of the parent shield 2, as shown in FIG.

-In addition, in the step of eccentricizing this child shield 3,
Water-tightness within the pile is ensured by the front partition wall 9 on the parent shield 2 side and the front partition wall 8 on the child shield 3 side.

After doing this, the front partition wall 8.8 fixed to the front end of the child shield 3 is separated from the child shield 3 by an operation from inside the child shield 3, and then the parent shield 3
While the cutter IO is rotated while the child shield 3 is moved forward independently from the parent shield 2, the face G is further excavated, thereby forming the face G. Peripheral wall T of the rear tunnel T.

Then, the segments are assembled using an erector device (not shown) and a primary lining is applied (not shown). A shield jack (not shown) is disposed at the rear end of the child shield 3, and the shield jack is extended by taking a reaction force from the front end of the segment, thereby moving the child shield 3 forward.

In this way, the steps of digging with the cutter 10, assembling the segments S, and advancing with the shield jack are repeated to form the track section.

As a result of the above, a large-diameter station portion and a small-diameter track portion are continuously formed.

According to the shield machine 1 of this embodiment, a normal track section and a station section connected thereto and having a larger diameter than the track section are continuously formed. Since the child shield 3 that excavates the part can be made eccentric, the parent shield 2 does not excavate unnecessary cross sections, that is, wasteful space, and most of the excavated cross sections can be used effectively. Therefore, in station areas, for example, there is no need for secondary construction such as filling in the bottom of a tunnel, which is required in the past, leading to a reduction in construction costs.

Although this embodiment shows an example of forming a subway tunnel, the shield machine 1 of the present invention can form various tunnels such as a sewer system.

"Effects of the Invention" As explained above, according to the shield machine of this invention,
An over cutter that protrudes in the radial direction to the same diameter as the parent shield is telescopically attached to the outer periphery of the cutter, and is also equipped with a slide mechanism that makes the child shield eccentric with respect to the parent shield. , the following excellent effects can be achieved.

In other words, when excavating tunnels such as subways using the shield construction method using the shield machine of this invention, it is necessary to excavate small diameter tunnels and coaxial large tunnels, as when using a shield machine in which both parent and child shields are fixed coaxially. Since a diameter tunnel is not excavated, a large diameter tunnel with a diameter larger than necessary will not be excavated. In other words, when forming a station section on one side of a track section, an unnecessary excavated cross section with the same width as the station section will not be formed on the opposite side of the station section, sandwiching the track section. Therefore, the entire excavated cross section can be used effectively, and unnecessary backfilling of the excavated cross section can be omitted, and secondary construction can be avoided as much as possible. Therefore, according to this shield machine, it is possible to efficiently construct a tunnel whose diameter partially expands, such as inside a subway station, and it is possible to reduce construction costs and shorten the construction period.

[Brief explanation of the drawing]

1 to 4 are views showing an embodiment of the present invention, in which FIG. 1 is a side sectional view of the shield machine, FIG. 2 is a front view, and FIG. 4 is a vertical sectional view when the sub-shield in FIG. 3 is eccentric. ■... Shield machine, 2... Parent shield, 3... Child shield, 4... Skin plate (parent shield side), (child shield side) 5... Skin plate 6... Frame, 7... Rear bulkhead, 8.9... Front bulkhead, 10... Cutter, 11...Rotating shaft, 12...Over cutter, 13...Shield jack G...Ground, G,...Face, S ... Segment, T ... Tunnel, T, ... Peripheral wall of the tunnel. (Parent shield side)

Claims (2)

[Claims] (1) A child shield having a cylindrical skin plate having a smaller diameter than the skin plate of the parent shield is arranged inside a parent shield having a cylindrical skin plate,
This shield machine is equipped with a cutter that forms an excavation cross section that is approximately the same as the cross section of the child shield in the front part of the child shield, and the outer circumference of the cutter has a diameter that is approximately the same as the diameter of the parent shield. A shielding machine characterized in that an overcutter projecting in a direction is telescopically attached, and a slide mechanism is provided for making the child shield eccentric with respect to the parent shield. (2) In the shield construction method using the shield machine described in paragraph 1, after forming a tunnel with the parent shield, the child shield is eccentric to the parent shield, and then the child shield is separated and independently from the parent shield. A shield construction method characterized in that by launching a tunnel, a tunnel that is smaller in diameter and eccentric than the tunnel formed by the parent shield is successively formed.