JPH01290899A - Intermittent stanchion construction in composite-cross section shield tunnel - Google Patents

Abstract

PURPOSE:To widen the work space between primary stanchions by prestressing and integrating stanchion, junctions of the right and left rings with a PC steel material inserted into a sheath and removing temporary stanchions located at the middle section. CONSTITUTION:Primary stanchions 4 or temporary stanchions 5 are assembled and supported between the upper and a lower stanchion junctions 3 and 3 of segments 2 and 2 assembled in the front and back. A sheath communicated between rings assembled in the longitudinal direction is buried in the junction 3 in advance. The PC steel material inserted into the sheath is prestressed, the front and rear junctions 3 are integrated. After synthetic beams are formed, the intermediate stanchions 5 are removed, the shaft force is applied to the stanchions 4 via the synthetic beams, rings 2 are connected in sequence for construction. A sufficient space is formed between the stanchions 4 and 4, and construction can be implemented with a margin.

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention is a composite section shield tunnel in which the supports installed between the left and right rings are constructed at intervals so as to maintain sufficient space between them. , Concerning construction methods for constructing underground stations, underground railway switching intersections, etc.

``Prior art and problems to be solved by the invention'' Recently, a seal construction method has been developed in which a tunnel with a composite cross-section is constructed by combining two circular rings on the left and right sides to form a double circular ring. In this construction method, a center column is assembled for each front and rear ring between the upper and lower column joints in the segment between the left and right rings, so sufficient space is maintained between the front and rear center columns. However, when constructing underground stations or interchanges for underground railroads, there was a problem in that the densely placed central pillars would get in the way.

``Means for Solving the Problems'' In order to solve the above-mentioned conventional problems, the present invention provides a sheath in which a plurality of rings in the excavation direction are connected in series as a set in advance at the strut joint in the segment between the left and right rings. of this set of rings, a permanent strut is assembled between the upper and lower strut joints of the ring located at the front and rear ends of the set, and a temporary strut is assembled between the upper and lower strut joints of the ring located in the middle. After introducing prestress and integrating the prestress by inserting the PC steel material through the sheath that communicates with each strut joint of a set of rings, the strut joints between each set of rings are removed by removing the temporary struts. The structure consists of an integrated composite beam, and the axial force of the removed intermediate temporary support supports is applied to the permanent support columns through this beam, thereby maintaining sufficient space between the permanent support supports. This paper proposes a construction method for constructing separate supports in complex cross-section shield tunnels, which enables the construction of underground stations and subway switching intersections that allow people and vehicles to pass through with ease.

"Embodiments" Below, embodiments of the present invention shown in the drawings will be described.
While excavating with a compound section shield excavator l equipped with a circular excavation cutter, assemble the segments backward one by one to construct a compound section shield tunnel in which a plurality of segment rings 2 overlap on the left and right, and between each ring 2. Assemble the segments forming the box-shaped flock-like column joint 3,
A permanent support 4 or a temporary support 5 is assembled and supported between the upper and lower support support joints 3.3 by bolt connection or the like for each ring assembled in the front and rear directions (FIG. 2(a)).

The strut joint 3 formed in the segment between the left and right rings 2.2 has a plurality of rings 2.2 and 2 assembled in the front and back direction.
- (In the illustrated embodiment, 5 rings) are set as a set, and a sheath 6 that communicates with these rings is buried in advance.

A main strut 4 is installed between the upper and lower strut joints 3, 3 of the ring 2 located at the front and rear ends of the set of rings 2, and the upper and lower strut joints 3 of the ring 2 located at the intermediate portion are provided. Assemble the temporary support 5 between .3 and 3.

Next, prestress is introduced into the sheath 6 that forms a series between each strut joint 3 of each set of rings 2 using a PC steel material 7 to integrate the strut joint 3, as shown in FIGS. 2(b) and 3. figure)
After constructing a composite beam that connects and integrates these, the intermediate temporary support 5 is removed, and the axial force that these supports is applied to the main support 4 through this composite beam, and thereby the main support Maintain sufficient space for the installation supports 4, 4 (see Figure 2 (C)
)).

The above steps are sequentially performed on a new set of rings 2 including the tip portions of the previous permanent supports 4, and the temporary supports 5 removed in the previous process are sequentially repurposed.

As a result, it becomes possible to construct an underground station, a switching intersection for an underground railroad, etc., where people and vehicles can pass between the main supports 4 and 4 with sufficient margin.

"Effects of the Invention" As described above, according to the present invention, a sheath is embedded in advance in the strut joint in the segment between the left and right rings, and the sheath is connected in series with a plurality of rings in the excavation direction as a set. Assemble a permanent strut between the upper and lower strut joints of the ring located at the front and rear ends of the ring, and a temporary strut between the upper and lower strut joints of the ring located in the middle,
After introducing prestress and integrating the pre-stressed steel material inserted into the sheath that communicates with each strut joint of a set of rings, the temporary struts are removed, so that the strut joints between each set of rings are integrated. The axial force that the removed middle temporary support had was applied to the permanent support via this beam, thereby maintaining sufficient space between the main supports to prevent people from entering the building. It will be possible to construct underground stations and interchanges for underground railways that allow vehicles to pass through with plenty of time.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a compound cross-section shield tunnel constructed according to the present invention, and Figures 2 (a), (b), (c)
) is a vertical sectional side view showing the process of this invention, and FIG. 3 is a cross sectional view showing a state in which prestress is introduced to the column joint in this invention. 1. Composite section shield excavator, 2. Segment ring, 3. Support column joint, 4. Permanent support, 5. Temporary support, 6. Sheath, 7. PC steel material. Figure 3Figure 2

Claims (1)

[Claims] 1) A sheath that connects a plurality of rings in the excavation direction as a set is buried in advance at the strut joint in the segment between the left and right rings, and the upper and lower A permanent strut is assembled between the strut joints, and a temporary strut is assembled between the upper and lower strut joints of the ring located in the middle, and the PC steel material is inserted into a sheath that communicates with each strut joint of the set of rings. 1. A construction method for constructing separate supports in a composite cross-section shield tunnel, characterized in that the temporary supports are removed after the temporary supports are integrated by introducing prestress.