JPS6216311B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an expansion shield machine in a construction method in which expansion excavation is carried out in an area scheduled for expansion in a tunnel that has been subjected to primary shielding, while the expansion shield machine is propelled along the outer periphery of the primary shield segment. This invention relates to a propulsion control method.

The applicant has proposed a tunnel expansion excavation method that improves the drawbacks of conventional construction methods.

This new excavation method involves locally expanding excavation at one end of the area planned for expansion within the tunnel where primary shielding has been performed, and installing another expanding shield machine here to extend around the outer periphery of the primary shield segment. Along with expanding excavation by propelling the excavation in the axial direction,
The secondary shield is applied to the enlarged excavation part while sequentially removing the primary shield segments of the enlarged excavation part.

The present invention also provides a propulsion control method for an expanding shield machine in the tunnel expanding excavation method, which comprises: providing a guide member on the inner circumference of the expanding shield machine;
The guide member is provided with a plurality of displacement detection means for detecting the positional relationship with the primary shield segment, and each shield jack is controlled based on the output signal of each displacement detection so that the gap positional relationship is constant. The main point is that the expansion shield machine was propelled.

As a result, the expansion shield machine can follow the curve of the primary shield segment and differences in the earth pressure of the expanded excavation area, and has developed a propulsion control method for the expansion shield machine that can always excavate the expansion area with high construction accuracy. This is what we provide.

An embodiment of the present invention will be described below with reference to the drawings.

First of all, Figure 1 is a longitudinal cross-sectional view showing the excavation construction of the expansion section, where 1 is the primary shield segment, 2 is the primary tunnel, 3 is the expansion shield segment, 4 is the expansion tunnel, 5 is the area to be expanded, and A is the expansion shield. It is a machine. The expanding shield machine A, like a normal shield machine, has a skin plate 6 with a cutting edge formed on the tip side, and a plurality of shield jacks 7a to 7h attached to the skin plate and having cylinders extending rearward protruding from the skin plate 6. However, unlike a normal shield machine, a guide ring 8 as a guide member having a diameter larger than the outer diameter of the primary shield segment 1 is formed inside the skin plate.

A skin plate 6 is installed on the tip side of the guide ring 8.
A similar cutting edge is formed on the inner circumferential surface of the skin plate, and a sealing member 1 made of a slidable rubber plate seals the gap 9 between the skin plate and the primary shield segment 1.
0 is attached all around.

Furthermore, displacement gauges 1 are installed on four sides of the guide ring 8.
1, 12, 13, and 14 are attached at equal angles, and detection rods 11a, 12a, 13a, and 14a each having a guide roller at the tip protrude from each of these displacement meters in a telescopic manner. As shown, it protrudes into the gap 9 adjacent to the rear of the shield member 10 and is slidably abutted on the outer circumferential surface of the primary shield segment 1.

Although not shown in detail, each of the displacement meters 11-14 is a known contact-type displacement meter that generates an electric signal according to the stroke of the detection rods 11a-14a. However, the means for detecting the positional relationship that can be used in the present application is not limited to the above-mentioned contact type displacement meter, and various non-contact type displacement meters using light, magnetism, etc. can also be used.

The expansion shield machine A has a structure in which several units are connected together using screw means in consideration of transportation and when creating an expansion section in the middle of the primary tunnel. In order to reduce equipment costs, a shield jack is installed in the hood to shorten the machine length, and a two-stage extended shield jack is used instead.

Next, the expansion shield machine A having the above-mentioned configuration has one end of the area to be expanded 5 from which some rings of the primary shield segment 1 provided around the outer periphery of the previously installed primary tunnel 2 are removed, although illustration is omitted. The shield jacks 7a to 7b are extended using the retaining plate stretched over the rear ground as a reaction force receiver, and the expansion shield machine A is pushed into the ground in the area 5 to be expanded in front. Then, an enlarged excavation of the ground is performed by an excavating means such as a screw auger (not shown) installed between the skin plate 6 and the guide ring 8. Then, the primary shield segment 1 on the inside that has been enlarged and excavated is removed, and the enlarged shield segment 3 is attached, and the attached enlarged shield segment is used as a reaction force receiver to sequentially perform enlarged excavation in the same manner as before.

The expansion shield machine A was propelled by each shield jack 7a to 7h, and at this time, the gap 9 between the guide ring 8 of the expansion shield machine and the primary shield segment 1 was uniform as shown in Fig. 2a. This is desirable.

However, the thrust force of each shield jack and the soil quality on the surrounding surface are not necessarily uniform, and especially when the primary shield is curved, the expanding shield machine becomes slanted as shown in Figure 2b, and the gap 9 is Not only will it be impossible to accurately expand and excavate, but the expansion shield machine will not be able to propel itself.

Therefore, in the present application, the displacement gauges 11, 12, 13, and 14 attached to the guide ring 8 and in contact with the primary shield segment 1 detect this deviation, and the output signals of the displacement gauges are used to move the shield jacks 7a to 7a. 8h so that it can always be propelled along the primary shield segment 1.

For example, if the left side in the drawing advances too much and the right side is left behind, as shown in Figure 2b, the right side gap 9
becomes larger, the stroke of the displacement meter 12 is extended, and the displacement meter 14 is contracted, causing a difference in the output signal of each displacement meter.

Therefore, depending on these output signals, either the shield jacks 7f and 7g linked to the displacement meter 14 are stopped, or the shield jacks 7b and 7 linked to the displacement gauge 12 are stopped.
c only, or each displacement meter 11~
The purpose is to correct the deviation by comparing the output fluctuations of 14 with standard values and giving the necessary thrust to each.

That is, the output signal of each displacement meter is amplified by an amplifier 15 as shown in FIG. 7a-7
Control h.

Various configurations are possible for the control device 17, but the simplest one is to provide the same number of electromagnetic on-off valves as displacement meters, and open and close each electromagnetic on-off valve using the amplified signal from each displacement meter to control each shield jack. Operation ON-OFF
Alternatively, the thrust force can be adjusted by controlling the fluid flow rate supplied to each shield jack using a flow control valve.

Further, the desired thrust force of each jack is set based on the data obtained from the display 16, data during primary shield excavation, etc., and this data or correction command is given to the control device 17 from the setting device 18. It is also possible to automatically control each shield jack 7a-7h.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view showing the excavation construction of the enlarged section, Figure 2 is an explanatory diagram showing the positional relationship of the expanding shield machine with respect to the primary shield segment, and Figure 3 is an enlarged view of the displacement meter installation part and its signal processing system. It is a diagram. [Explanation of symbols] 1...Primary shield segment, 2...Primary tunnel, 3...Expansion shield segment, 4...Expansion tunnel, 5...Expansion planned area, 6...Skin plate, 7a to 7h... Shield jack, 8... Guide ring, 9... Gap, 10... Seal member, 11, 12, 13, 1
4... Displacement meter, 15... Magnifier, 16... Display, 17... Control device, 18... Setting device, A...
Expanding shield machine.

Claims (1)

[Claims] 1. An expanding shield machine is installed at one end of the area to be expanded in the tunnel where the primary shielding has been performed, and the expanding shield machine is propelled in the axial direction along the outer periphery of the primary shield segment to perform expanded excavation. In a tunnel expansion excavation method in which a secondary shield is applied to the enlarged part while sequentially removing the primary shield segments of the enlarged excavation part, the enlarged shield machine is installed along the primary shield segment on the inner periphery of the enlarged shield machine. A guide member for guiding the primary shield segment is provided, and the guide member is provided with a plurality of displacement detection means for detecting the gap positional relationship between the guide member and the primary shield segment, and the gap position is determined based on the output signal of each displacement detection means. A propulsion control method for an expanding shield machine, characterized in that the expanding shield machine is propelled by controlling each shield jack so that the relationship is constant.