JPH0336397B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to an eccentric construction of an existing shield tunnel in an area to be expanded on the outer periphery of an existing shield tunnel, in order to form, for example, a subway station premises or a sewer pipe connection part. This paper relates to an enlarged excavation method for excavating enlarged tunnels.

(Prior art) Conventionally, this type of enlarged excavation method was
As shown in the figure, a shielding machine main body c has a double inner and outer cylindrical structure consisting of an inner cylinder a for guiding and an outer cylinder b for shielding, which are eccentric to each other. Generally, an expanding shield machine f equipped with a plurality of propulsion jacks e is propelled in the axial direction along the outer circumference of an existing shield tunnel g to excavate the outer circumference of the shield tunnel.

(Problems to be Solved by the Invention) The conventional expansion excavation method has a propelling jack e and a blade part d between the inner cylinder a and the outer cylinder b of the shield machine body c of the expansion shield machine f used. Since an installation space or a discharge space for excavated soil must be provided, the inner cylinder a and the outer cylinder b cannot be brought very close to each other, and therefore it is not possible to excavate an enlarged tunnel with a large eccentricity with respect to the existing shield tunnel g. This has the following disadvantage.

In order to solve the above-mentioned inconvenience, the present applicant has proposed in patent application (1) filed at the same time that the region of the inner cylinder of the conventional expanding shield machine that is close to the outer cylinder is convex inwardly along its entire length along its axial direction. However, it is desired to propose an efficient method for excavating an enlarged tunnel using such an expanding shield machine.

(Means for Solving the Problems) An object of the present invention is to provide an efficient enlarging excavation method that satisfies the above-mentioned requirements. This is an enlarged excavation method for excavating enlarged tunnels, in which a blade is installed on the front side in the direction of propulsion of the shield machine body, which has a dual inner and outer cylindrical structure, consisting of an inner cylinder for guiding and an outer cylinder for shielding, which are eccentric to each other. It has a mouth and a plurality of propulsion jacks along the inner periphery of the outer cylinder, and a region of the inner cylinder adjacent to the outer cylinder is convexed inward over its entire length along its axial direction. In an expansion excavation method in which an expansion shield machine is propelled in the axial direction along the outer circumference of the shield tunnel to excavate the outer periphery of the shield tunnel, when constructing the existing shield tunnel, a convex part of the inner cylinder of the expansion shield machine is Segments of corresponding areas to be expanded are connected to each other in the axial direction, and prior to propulsion of the expanding shield machine, the connected segments are extracted axially from the shield tunnel and removed from the inner cylinder of the expanding shield machine. It is characterized by forming a continuous region into which the convex part fits.

(Example) An example of the enlarged excavation method of the present invention will be described below with reference to the accompanying drawings.

In the figure, reference numeral 1 shows an expanding shield machine used in the expanding excavation method of the present invention, in which a plurality of shield machine dividing units 2 each having a substantially fan-shaped cross section are assembled into a donut shape with bolts or the like, and a guiding inner cylinder 3 eccentric to each other is assembled. The main body 5 of the shielding machine has a double inner and outer cylindrical shape, consisting of an outer cylinder 4 for shielding, and a fixed cutter-type cutting edge part 6 is provided along the inner circumference of the edge of the main body 5 in the direction of propulsion. The dividing unit 2 is located behind the blade mouth portion 6.
A propulsion jack 7 is provided for each inner cylinder 3 of the main body 5.
Two portions of the shield machine division unit 2 in the area where the and outer cylinder 4 are close to each other are made to protrude inward so that the inner cylinder side is separated from the outer cylinder side. Instead of the fixed cutter, the blade mouth portion 6 may be configured to include a rotary cutter, a muddy excavation device, or the like between the inner cylinder 3 and the outer cylinder 4 of the shield machine body 5.

Reference numeral 8 in the figure indicates an existing shield tunnel, and when constructing the shield tunnel 8, segments 11 corresponding to the convex portion 10 of the inner cylinder 3 of the expansion shield machine 1 are bolted together in the planned expansion area 9 of the central area. In addition to being connected in the axial direction, these segments 11 are connected to other segments 12 constituting the existing shield tunnel 8 with bolts or the like.

Existing shield tunnel 8 constructed as described above
Although not shown, a starting base for the expansion shield machine 1 is constructed at one end of the planned expansion area 9 by, for example, excavating a vertical shaft or using the expansion shield excavation method (Japanese Patent Application Laid-open No. 59-21892) proposed earlier by the present applicant. Next, the connections between the segments 11 connected to each other in the axial direction of the existing shield tunnel 8 with other segments 12 are loosened by removing bolts, etc., and the connected segments 11 are moved into the launch base by the arrow. While pulling out in the direction of A, the connections between the segments 11 are sequentially loosened by removing bolts, etc., and they are dismantled, and the convex part 10 of the inner cylinder 3 of the expansion shield machine 1 is fitted into the existing shield tunnel 8 and propelled. A continuous region 13 is formed.

Note that a support 15 is interposed between the segments 12 at both ends of the continuous region 13 using brackets 14 provided in advance on each segment 12 at both ends, and is connected to the support 15 in the axial direction. A filling material 1 such as mortar is placed in the space between the segments 11.
6 to reinforce the existing shield tunnel 8.

Next, the expansion shield machine 1 is assembled and installed in the starting base, the convex part 9 of the inner cylinder 3 of the expansion shield machine 1 is fitted into the continuous area 13 of the existing shield tunnel 8, and a suitable countermeasure (not shown) is installed. The expanding shield machine 1 is propelled in the axial direction along the outer periphery of the existing shield tunnel 8 by the propulsion jack 7 while taking a reaction force by receiving the force, thereby excavating the outer periphery of the existing shield tunnel 8. The excavated soil is discharged to the rear of the expanding shield machine 1 through a region formed between the inner cylinder 3 and the outer cylinder 4 of the expanding shield machine 1. Next, the remaining segments 12 in the inner cylinder 3 of the expanding shield machine 1 are disassembled, and segments for the expanding tunnel are assembled behind the expanding shield machine 1, and this segment is used as a reaction force to receive the reaction force and the propulsion jack 7 is used for the expanding shield machine. 1 is further advanced to excavate the outer periphery of the existing shield tunnel 8.

Such excavation work is repeated to form an enlarged tunnel eccentrically around the outer periphery of the existing shield tunnel 8.

In the embodiment described above, an example was shown in which the central region of the existing shield tunnel 8 is enlarged and excavated, but it goes without saying that a desired region such as one end region or the entire region of the existing shield tunnel 8 can be enlarged and excavated.

(Effects of the Invention) According to the present invention, when constructing an existing shield tunnel, the segments of the area to be expanded corresponding to the convex portion of the inner cylinder of the expanding shield machine are connected to each other in the axial direction, and the expansion Prior to the propulsion of the shield machine, the connected segments are extracted from the shield tunnel in the axial direction to form a continuous region into which the convex portion of the inner cylinder of the expansion shield machine is fitted. The area into which the convex part of the inner cylinder of the shield machine fits can be easily formed, and the convex part of the inner cylinder of the expanding shield machine can be inserted into the continuous area thus formed and the area can be continuously propelled. This has the effect of efficiently excavating an enlarged tunnel that is relatively largely eccentric from the shield tunnel in the planned expansion area.

[Brief explanation of drawings]

Figure 1 is a front view of the expansion shield machine used in the conventional expansion excavation method when it is propelling the outer periphery of an existing shield tunnel, Figure 2 is its - line sectional view, and Figure 3 is the expansion shield machine used in the expansion excavation method of the present invention. A front view of the outer periphery of the existing shield tunnel of the expanding shield machine to be used in a propulsion state, Figure 4 is a sectional view taken along the - line, Figure 5
The figure is a perspective view showing a state in which segments of an existing shield tunnel are removed. 1... Enlarged shield machine, 3... Inner cylinder, 4... Outer cylinder, 5... Shield machine body, 6... Blade mouth, 7...
...Propulsion jack, 8...Existing shield tunnel,
9...Expansion planned area, 10...Convex part, 11...
Segment, 13...Continuous area.

Claims (1)

[Claims] 1. An expansion excavation method for excavating an expansion tunnel eccentric to the existing shield tunnel in the planned expansion area on the outer periphery of the existing shield tunnel, which consists of an inner cylinder for guiding and an outer cylinder for shielding which are eccentric to each other. A double cylindrical shield machine body is provided with a cutting edge on the front side in the direction of propulsion, and a plurality of propulsion jacks are provided along the inner periphery of the outer cylinder, and a region of the inner cylinder close to the outer cylinder is provided. In an expansion excavation method in which the outer periphery of the shield tunnel is excavated by driving an expanding shield machine that is convex inward along the entire length of the shield tunnel in the axial direction along the outer periphery of the shield tunnel, the existing shield When constructing a tunnel, segments of the area to be expanded corresponding to the convex portion of the inner cylinder of the expanding shield machine are connected to each other in the axial direction, and prior to propulsion of the expanding shield machine, the connected segments are connected to each other in the axial direction. An expansion excavation method characterized by forming a continuous area into which a convex part of an inner cylinder of the expansion shield machine is inserted by extracting it from the shield tunnel in the axial direction.