JPS6346240B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an expansion shield excavation method for expanding the diameter of an existing tunnel.

(Prior art) The present applicant previously filed a patent application for this type of construction method in 1982-
No. 215322, installing guide rings along the circumferential direction at both ends of the area scheduled for expansion of the existing tunnel,
A part of the primary shield segment between the rings is peeled off, and the ground in the peeled off area is excavated to form a base cavity. engaging the engaging pieces provided on both sides and engaging the engaging pieces provided on both sides of the circumferential segment fixed to the rear of the excavator;
We have proposed a method in which the rear part of the circumferential segment is pressurized by a jack so that it can be expanded by moving forward along the guide ring of the excavator.

(Problems to be Solved by the Invention) However, in such an excavation method, not only is it difficult to arrange the guide ring, but also a large pressure force is applied to the shield excavator that simply engages the guide ring. Therefore, there were problems such as the pressure means becoming bulky.

(Means for Solving the Problems) The present invention aims to solve the above problems by installing partial guide rings in advance at both ends of the planned expansion area of an existing tunnel consisting of primary shield segments. and a partial movable ring that is inserted into the partial guide ring, and the movable ring in the circumferential direction is attached by connecting the partial guide ring and the partial movable ring. A guide ring in the circumferential direction into which the guide ring is inserted is formed, a part of the primary shield segment between the shield segments with the guide ring is peeled off, and the ground at the peeled part is enlarged and excavated to form a base cavity. A shield excavator for outer circumferential excavation and a circumferential segment connected to the excavator are attached to the movable ring within the base cavity, and the shield excavation is performed by pressurizing the circumferential segment with a pressurizing device on the back side. The machine is sequentially excavated in the circumferential direction of the existing tunnel along the guide ring, and the circumferential segments of the same shape are sequentially connected to the circumferential segment at the rear of the shield excavating machine that excavates, and the circumferential segments are made into a movable ring. The method is characterized in that the area to be enlarged is enlarged by being fixed and sealed by continuous fixation of circumferential segments.

(Example) The present invention will be explained below based on the drawings. Reference numeral 1 indicates an existing tunnel. The tunnel 1 is formed by assembling primary segments 2. At both ends of the planned expansion area of the tunnel 1, partial sections are provided in advance. The guide ring-equipped shield segments 2a, 2a each having a guide ring and a partial movable ring fitted into the partial guide ring are installed, and these partial guide rings and partial movable rings are attached. By this connection, a circumferential guide ring 3 into which a circumferential movable ring 4 is fitted is formed. Then, in the tunnel 1, a part of the primary segment 2 between the guide ring-attached shield segments 2a, 2a is separated linearly, and the base cavity 5 is formed by enlarging and excavating the ground in the separated area.

Then, within the base cavity 5, the movable ring 4,
A shield tunneling machine 6 for outer circumferential excavation is attached to 4, and the tunneling machine 6 is formed with a rectangular frame body whose front surface is a blade surface, and a circumferential segment 7 is attached to the back surface of the shield tunneling machine 6.
one of the circumferential segments 7 is fixed, the inner peripheral edge of the segment 7 is also fixed to the movable rings 4, 4, and then the back surface of the circumferential segment 7 is placed in the base cavity 5. By shield tunneling machine 6
The existing tunnel 1 is excavated in the circumferential direction along the guide ring 3, and the circumferential segments 7 are successively fixed behind it to form an enlarged tunnel sealed with the circumferential segments 7. In the figure, 9 is a cover to prevent dirt from entering the guide ring 3, and 10
indicates the reaction force receiver of jack 8.

(Effects of the Invention) As described above, according to the present invention, a guide ring including a guide ring 3 and a movable ring 4 fitted into the ring 3 is provided at both ends of the planned expansion area of an existing tunnel consisting of a primary shield segment. Install the shield segments 2a, 2a, peel off a part of the primary shield segments 2, 2... between the shield segments 2a, 2a with guide rings,
A base cavity 5 is formed by enlarging and excavating the ground at the peeled part, and the movable ring 4,
A shield excavator for outer circumferential excavation is attached to the outer circumferential excavation machine and a secondary shield is fixed to the excavator, and the shield excavator is sequentially attached to the guide ring by pressurization by the pressurizing device 8 on the back of the secondary shield segment. Since the tunnel was excavated in the circumferential direction of the existing tunnel, the installation of the guide ring in the area planned for expansion is compared to installing the guide ring separately from the segment as in the previous application mentioned above, and installing it by engaging the shield excavation machine. This not only makes it easier to install the guide ring, but also allows smooth sliding within the guide ring of the shield excavator, reducing the load on the pressurizing device and simplifying the device, as well as the excavation work. It has effects such as being able to increase efficiency.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the tunnel under construction, Figure 2 is an enlarged view of part A in Figure 1, and Figure 3 is a - of Figure 1.
FIG. 1... Existing tunnel, 2... Primary shield segment, 2a... Shield segment with guide ring, 3... Guide ring, 4... Movable ring,
5...Base cavity, 6...Shield excavator, 7...
Circumferential segment, 8...pressure device.

Claims (1)

[Claims] 1. Installing shield segments that are equipped with a partial guide ring and a partial movable ring that is inserted into the partial guide ring in advance at both ends of the planned expansion area of the existing tunnel consisting of the primary shield segment, The connection between these partial guide rings and the partial movable ring forms a circumferential guide ring into which the circumferential movable ring is inserted, and a part of the primary shield segment between the shield segments with the guide ring. and expand and excavate the ground in the peeled part to form a base cavity, and a shield excavator for excavating the outer periphery and a circumference connected to the excavator, which exists in the base cavity and is attached to the movable ring. segment is attached, and the shield excavator is sequentially excavated in the circumferential direction of the existing tunnel along the guide ring by pressurization by a pressurizing device on the back of the circumferential segment, and the shield excavator is The area to be expanded is expanded by sequentially connecting circumferential segments of the same shape to the circumferential segment, fixing the circumferential segments to a movable ring, and sealing the circumferential segments by continuously fixing them. Expanded shield excavation method.