JPS60115798A - Secondary convering construction method of shield tunnel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for inserting and holding a recess in a joint between segments into a thin metal machine when performing secondary stage construction on the primary lining of segments in tunnel excavation using the shield method. A secondary shield tunnel characterized in that the surface is smoothed by closing with a lid formed of a piece, and then a secondary lining is applied to the entire surface to prevent cracks from occurring in the secondary lining. It concerns the lining construction method.

Excavation of a tunnel using the shield method 1') When performing a secondary concrete lining for the primary lining using segments at the time of 11, the shrinkage that occurs when the concrete cools and the temperature rises due to the heat of water in the cement and when it dries. As shown in Figure 8, it has been found that shrinkage is generally restrained by the primary chi'rie a on the back surface and causes a crack C from the secondary chie. In order to reduce the rise in temperature of concrete due to the heat of hydration, no particularly effective measures have been taken other than reducing the elements E, lt and f or using low heat generation cement. However, the latter type of concrete using cement has disadvantages such as the length of the formwork. Moreover, it is currently impossible to prevent cracks caused by drying and shrinkage across the long ribs after secondary machining is installed.

Therefore, as a result of various grinding processes, the surfaces of the segments of the next machining process were smoothed, and in particular, in the case of slave type segments, the recesses for the joint fittings provided at the joints between the segments, and the recesses in the core type segments. We were told that cracks would occur due to the interaction between the concrete part filled in the middle section and the segment during the 9th construction of the secondary girder, so we closed this recess in advance to make it a smooth surface. They came up with the idea of performing secondary machining uniformly on the entire surface. By the way, as a construction method, for example, it is possible to fill the recessed portion with concrete IJ-gap to smooth the surface and then carry out a toshitsu process. It is also possible to fit blocks made of concrete or plastic into the four parts and then apply a secondary lining to the entire surface.
This construction method requires a special formwork to form the blocks, and it is also necessary to take measures to secure the blocks after they are placed in the recesses of the segments.

In addition, the shape is not only inflexible, but also requires a lot of means to carry it in and install it because it is a military camp, so as a result of supplementary research, the four parts were made of thin metal plates such as corrugated iron or tin. If we explain the construction method using the example shown in the drawings, as shown in Fig. 1 (1), for example, a thin metal rib such as galvanized iron is used to close the segment, which is thicker than the four parts for the joint fittings. Make the lid body shaped into a shape, and cut 12+, (
2I and t3+, +3 (set the lower folded insertion piece (4),
(4)' is configured in J configuration. When inserting the bent insertion pieces (4) and (4) into the recesses, please refer to Figures 2 to 4.
As shown in the figure, bend the insertion piece (411 (4)
', and this insertion piece is inserted into the recesses B and l (
After joining the fittings A, C, and C' of the + joint part with bolts D, there is no body (1+ bent insertion piece ta, (4f
straddle both concave y, B B, B' and its 1il
It is inserted so as to be in pressure contact with ll 9 to cover all four parts to make the surface smooth, and then a second Enoki concrete E is poured over the entire surface.

As mentioned above, after covering the four parts for the joint metal fittings in the primary lining segment with thin coating to make the surface smooth, concrete IJ-toni secondary sanding is performed to cool down the temperature that has risen due to water heating of the concrete. Even during shrinkage that sometimes occurs or shrinkage during drying, there is no risk of cracking because it is not restrained by the primary welding on the back. Moreover, since this lid body is made of a thin metal layer, it is not only lightweight and easy to transport and install, but also because it is held in pressure contact with the recess (liil9) by the elasticity of the bent insertion piece. Does not require holders etc.
Moreover, it is easy to manufacture and has various effects such as being able to be molded on site to suit the condition of the recess.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the main body, Fig. 2 is a plan view with the insertion piece folded, Fig. 3 is a 1111 side view of the same, Fig. 4 is an orthogonal view of the same,
Fig. 5 is a cross-sectional front view after construction according to the present invention, Fig. 6 is a partial slope view showing the fitting state, Fig. 7 is a partially cutaway plan view of the same, and Fig. 8 is a partially cutaway view of an example of the conventional construction method. It is a slope view. (11... Lid body, (2), (2 I, 31, +3 I)
・Cut, (4), (41...Bent insertion piece, A, A'
...Segment, H1B'...Concavity, c, c'...
Joint fittings, 1)...Pol 1",)'j...Secondary ridge econcrete. Patent applicant in 1:111iAs Construction Co., Ltd. Hikari 71 people Paralysis 2 Kokudai Z Figure left, 5' Figure

Claims (1)

[Claims] When constructing a shield tunnel, primary repair work is performed by making cuts in the inner edge of a thin metal plate such as galvanized iron or tin plate for the four parts of the segment joint fittings, and inserting a lid body with bent insertion pieces corresponding to the four parts. A secondary lining construction method for a shield tunnel, which is characterized in that after closing the four parts and smoothing the surface, secondary hammering concrete is placed.