JPS6346238B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an enlarged shield construction method that improves construction efficiency.

(Prior art) As shown in Fig. 1, the previously proposed expansion shield construction method involves removing a part of the primary shield segment 2 (hereinafter referred to as primary segment 2) that forms the normal diameter tunnel 1, and An annular cavity 3 is excavated at the location, and an expanding shield machine 4 is installed inside the cavity 3.
is assembled, and the expansion shield machine 4 is excavated around the primary segment 2 and along the area to be expanded 5 to excavate an expansion tunnel. The expansion shield machine 4 is equipped with an excavation blade 4a, a seal 6 that slides on the outer periphery of the primary segment 2, and a propulsion jack 7, and as the expansion excavation progresses, the primary segments 2a in the area to be expanded 5 are sequentially removed. be done.

Further, the cavity 3 serves as a starting base for the expanding shield machine 4, and a circumferential shield construction method has already been proposed for forming the cavity 3. To explain this construction method based on Figures 2 to 9, first, as shown in Figures 2 to 3, a hole is dug at the location where a part of the primary segment 2 has been removed, and a circumferential shield with a U-shaped cross section is inserted into the hole. The machine 10 is loaded and excavated in the circumferential direction along the guide ring 11 to form the cavity 3. This will be explained in more detail based on FIGS. 4 to 9. As shown in Fig. 4, a steel box 12 is placed at the location h where the primary segment 2 is removed.
Bury the desired number of. At this time, a jack 13 is used as shown in FIG. Next, as shown in FIG. 6, the soil inside the box 12 is removed and the circumferential shield machine 10 is installed inside. And the original pusher 14
The circumferential shield machine 10 is propelled toward the side of the box 12 from which one wall has been removed. At the rear of the circumferential shield machine 10, as shown in FIGS. 7 and 8,
Excavation of the cavity 3 is continued by sequentially connecting circumferential segments 15 having the same shape with bolts or the like. Finally, a cavity 3 is formed which is completely covered with circumferential segments 15 as shown in FIG. Incidentally, when propelling the expanded shield machine 4 assembled within the cavity 3, it goes without saying that one side plate (mount plate) of each circumferential segment 15 is removed.

By using the above-described expansion shield construction method and circumferential shield construction method, construction work to expand at least a portion of an existing tunnel becomes extremely efficient.

(Objective of the Invention) An object of the present invention is to provide an expansion shield construction method that can make the above-mentioned expansion tunnel excavation more efficient.

(Summary of the Invention) The present invention forms an annular cavity in a part of a normal-diameter tunnel using a circumferential shield machine and multi-divided circumferential segments that are sequentially connected integrally on the rear side of the circumferential shield machine, and then An enlarged shield machine is formed mainly using circumferential segments, and this is arranged in the direction of extension of the normal diameter tunnel (direction of extension of the primary segment).
The main idea is to excavate the tunnel to form an enlarged tunnel.

(Example) The present invention will be described below based on an example shown in FIGS. 10 to 12. Note that the same reference numerals will be used to describe the same parts as in the prior art.

The circumferential shielding machine 10 used in the present invention is similar to that of the conventional construction method, and as shown in FIG. ) 24 and is equipped with a circumferential propulsion jack 27.
Further, the circumferential segment 20 includes a pair of fan-shaped retaining steel members 21 and 22 that are arranged facing each other with a distance between them.
and an outer peripheral plate 23 that connects the wide end portions 21a and 22a of these steel materials. The one steel material 21 for retaining the threads is attached to the outer circumferential plate 23 via a desired frame 25, and
It is removably attached to the The other steel material 22 for retaining the threads is entirely detachably attached to the outer circumferential plate 23.

The outer circumferential plate 23 has an enlarged digging blade (blade mouth) 26 on the edge side to which the frame 25 is attached, and it is possible to attach a propulsion jack 28 in the extending direction of the outer circumferential plate 23 on the inner surface thereof. There is.

Note that the circumferential segment 20 is configured to be able to connect a large number of divided circumferential segments having the same shape, and therefore a connecting plate 29 having connecting bolt holes and its cushion material 30 are used. A cushion material 31 is also provided between the outer peripheral plate 23 and the steel material 22.

Next, the construction method of the present invention will be explained while explaining the function of the circumferential segment 20 described above.

The circumferential shield machine 10 is installed in a hole dug by removing a part of the primary segment 2, similar to the previously proposed one, and is installed in a hole dug by removing a part of the primary segment 2.
7 to form a cavity 3. At this time, on the rear side of the circumferential shield machine 10, (circumferential segments) 20 having a similar shape are successively connected together using bolts or the like. The difference between this circumferential segment 20 and the conventional circumferential segment 15 is mainly that it incorporates a propulsion jack 28 and an enlarged digging blade (cutting edge) 26 in the direction of extension of the primary segment.

After the cavity 3 is completed, the circumferential shield machine 20 and the steel members 21 and 22 for retaining the peaks of each circumferential segment are removed, and desired parts (not shown) such as a tail and a tail seal are attached, and the expanding shield machine 20A is installed. After forming, the propelling jack 28 is used to excavate in the extending direction of the primary segment 2 to form an expanded tunnel in the area 5 to be expanded.

Note that the circumferential segment 20 is assembled in an annular shape and supports the inner wall of the cavity 3, similar to the previously proposed circumferential segment shown in FIG.
0, at least some of the propulsion jacks 2
8 is pre-installed.

Further, after the cavity 3 is completed, the circumferential shielding machine 10 is usually replaced with a circumferential segment 20 having a similar shape, but as described above, the main body of the circumferential shielding machine 10 is replaced with an enlarged shielding machine 20A. It may also be used as a part.

Furthermore, as shown in Fig. 10, the expansion shield machine 2
When 0A excavates, a secondary segment 2A is assembled in advance in an annular shape around the inner periphery of the 0A so that the inner surface of the cavity 3 can be supported.

(Effects of the Invention) According to the present invention, an expanding shield machine is constructed using circumferential shield segments stretched at a starting base, so it is possible to save equipment and shorten assembly time. In addition, unlike the conventional method of installing an expanding shield machine inside the circumferential segment, there is no need to excavate the inner diameter of the starting base by at least the thickness of the circumferential shield segment, so the amount of excavation increases by that amount. In addition, the circumferential segment can be made small in diameter, and there is no step difference between the outer diameter of the cavity after the expanding shield machine has started and the outer diameter of the expanding tunnel in front. It is economical as it requires less concrete for the next lining.

[Brief explanation of the drawing]

Figure 1 is a schematic sectional view showing the previously proposed expanded shield construction method, Figure 2 is a schematic sectional view showing the previously proposed circumferential shield machine, Figure 3 is an enlarged view of the line range in Figure 2, and Figure 4 is a schematic sectional view showing the previously proposed expanded shield method. Fig. 9 is a schematic process diagram showing the previously proposed circumferential shield construction method, Fig. 10 is a schematic sectional view showing an example of the method of the present invention, and Fig. 11 is a circular diagram used in the enlarging shield method of the present invention. A side sectional view of the circumferential shield machine, and FIG. 12 is a perspective view showing details of the circumferential segment. 1...Normal diameter tunnel, 2...Primary shield segment, 3...Cavity, 4...Expanding shield machine,
5...Expansion planned area, 20...Circumferential shield machine,
20...Circumferential segment, 20A...Enlarged shield machine, 21, 22...Steel material for thread retention, 23...Peripheral plate, 24...Circumferential drilling blade (blade mouth), 25...
...Frame, 26...Enlarged drilling blade (blade mouth), 27
... Circumferential propulsion jack, 28... Lateral propulsion jack, 29... Connecting plate, 30, 31... Cushion material.

Claims (1)

[Claims] 1. Remove a part of the primary segment installed in the area scheduled for expansion of the existing tunnel, and excavate its outer periphery to enlarge it using a circumferential shield machine that excavates in the circumferential direction.
The side plate on the starting side is located on the starting side of the expansion shield machine and has a fan-shaped outer shape, and the opening part of the frame is closed with a removable plate material for fixing the plate. The enlarging excavation is performed on a circumferential segment having a plate material for retaining the ridge forming the side plate, and an arc-shaped outer circumferential plate having a cutting edge formed at the tip of the starting side and connecting the wide ends of the side plates in a constructional manner. The starting base is built by sequentially extending the inner surface of the parts in a connected state, and then each of the plate members for fixing the ridges of the circumferential segments assembled in an annular shape is removed to form the main body of the enlarged shield machine, and the enlarged shield An expanding shield machine is configured using the machine body and a propulsion jack attached to the outer peripheral plate in advance or after a starting base is provided, and the expanding shield machine is excavated in the extending direction of the primary segment to form an expanded tunnel. Expansion shield construction method characterized by construction.