JP4451969B2 - Secondary lining concrete placing method and formwork - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for placing secondary lining concrete, and more particularly, to a method for placing secondary lining concrete that is unlikely to cause a cold joint at a tunnel top end and a formwork used therefor.
[0002]
[Prior art]
When building a tunnel using the shield method, concrete lining is applied to the inner periphery of the segment. In this case, a centle (steel formwork) is provided on the inner periphery of the shield, and concrete is placed between the centle and the segment. As a method for placing the secondary lining concrete, various improvements have been made as disclosed in, for example, JP-A-11-93592.
[0003]
[Problems to be solved by the invention]
When placing secondary lining concrete, the concrete is poured between the segment 100 and the centle 103. More specifically, the filling is performed from below the tunnel, and finally the top end is filled. The top end portion is filled from the concrete outlet 103a provided at the top end portion as shown in the schematic cross-sectional view of FIG. 4. However, as shown in the schematic plan view of FIG. Part of the concrete may adhere to the top of the Centle 103. If it adheres to the tunnel cross-section direction, there is no problem because it flows down due to gravity, but if it adheres to the tunnel longitudinal direction, it is difficult to flow down. There was a possibility of causing.
In order to reduce the cause of a cold joint, the present invention is to provide a method of dropping fresh concrete adhering to a tunnel top end portion before hardening and a formwork used therefor.
[0004]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is a secondary lining concrete placing method, and a concrete pipe connection port (for example, a blow-up port) provided at a top end portion of a formwork (for example, a centle 1). 12) The concrete is placed while vibrating the peripheral portion (for example, the vibration mold 11).
[0005]
According to the present invention , even if the fresh concrete adheres to the top end of the formwork, it flows down without stopping in place due to vibration. Therefore, it is less likely that the concrete adhering to the formwork top end will begin to harden, thereby reducing the possibility of a cold joint occurring at the tunnel top end.
[0006]
The present invention provides a secondary lining concrete placing method in which the peripheral portion is separated from the mold body and the pipe connection port, and the vibration isolating means (for example, cushion rubber) is capable of vibrating in the mold body and the concrete pipe connection port. 13). According to the present invention , since the outer peripheral portion and the concrete injection portion are connected to the peripheral portion via the vibration isolating means, vibration is not transmitted to other portions than the peripheral portion. Therefore, there is no possibility of trouble due to vibration.
[0007]
The present invention is a formwork (for example, centle 1) used for placing secondary lining concrete, and is a part of the formwork. The formwork body vibrates via a vibration isolating means (for example, cushion rubber 13). A vibration part (for example, vibration mold frame part 11) that can be connected and a pipe connection port (for example, blow-up opening 12) that is provided through the vibration part and holds the concrete pipe (2) through a vibration isolating means. And a vibrating means (for example, vibrator 14) for vibrating the vibrating portion. According to the present invention , a formwork used in the above- described invention can be provided.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the configuration will be described.
The center 1 (formwork) is a formwork for placing the secondary lining concrete, and has substantially the same configuration as the known formwork for placing the secondary lining concrete except for the structure of the inspection window 10 at the top end. is there.
[0009]
As shown in the schematic cross-sectional view of the main part in FIG. 1 and the main part plan view in FIG. 2, the inspection window 10 separates the vibration mold frame part 11 (peripheral part and vibration part) from the centle main body 1 a and the air outlet 12. It is configured to be connected to the center body 1a and the blow-up port 12 via a cushion rubber 13.
[0010]
The vibratory mold part 11 is assembled with a vibrator 14 (vibration means) for molds that vibrates the vibratory mold part 11.
[0011]
The cushion rubber 13 is provided so as not to transmit vibration by the vibrator 14 to other than the vibration mold frame portion 11.
The blow-up port 12 is opened and closed by a hydraulic actuator 10a, and becomes a pipe connection port for connecting the tip of the concrete pipe 2.
[0012]
Next, the construction method using the centle 1 will be described.
This construction method is the same as the construction method using the well-known secondary lining concrete placement form, except for the concrete placement at the top end. That is, a concrete hose is inserted from the inspection window 10 and concrete is placed between the center 1 and the segment 100.
[0013]
Then, when performing concrete placement at the top end, as shown in FIG. 3, the concrete pipe 2 is connected to the blowing port 12, and the concrete placement is performed while vibrating the inspection window 10 with the vibrator 14. At this time, the concrete is placed sequentially from the lap side (the side on which the secondary lining concrete 101 has already been placed) from the side of the end plate (from the right side to the left side in FIG. 3). In FIG. 3, the left inspection window 10 is not shown in detail.
[0014]
Here, fresh concrete adheres to the periphery of the blowing port 12, that is, the inspection window 10 immediately after placing the concrete, but since the inspection window 10 vibrates, it flows down without staying at the adhering place. That is, unlike the conventional case, even when fresh concrete adheres in the tunnel longitudinal direction (left and right direction in the figure with respect to the blow-up port 12), since it flows down to the surroundings due to vibration, solidification does not proceed at that location.
[0015]
Therefore, the possibility of a cold joint occurring at the top of the secondary lining concrete is reduced.
[0016]
In the above embodiment, the concrete is placed from the inspection window 10. However, the present invention is not limited to this, and an opening dedicated to concrete placement may be used.
In addition, it is needless to say that specific components can be appropriately changed without departing from the spirit of the invention.
[0017]
【The invention's effect】
According to the present invention , it is unlikely that the concrete adhering to the top end of the form will begin to harden, thereby reducing the possibility of a cold joint occurring at the top end of the tunnel.
[0018]
According to the present invention , since vibration is not transmitted to other portions than the peripheral portion, there is no possibility of trouble due to vibration. Moreover, according to this invention , the formwork used for the above- mentioned invention can be provided.
[Brief description of the drawings]
FIG. 1 is an enlarged view of a main part of a cross section in a tunnel longitudinal direction of a mold according to an embodiment to which the present invention is applied.
FIG. 2 is a diagram showing a configuration of an inspection window of the mold shown in FIG.
3 is a schematic plan view of the mold shown in FIG. 1. FIG.
FIG. 4 is a schematic cross-sectional view illustrating a conventional method for placing secondary lining concrete.
FIG. 5 is a schematic plan view for explaining a conventional method of placing secondary lining concrete.
[Explanation of symbols]
1 centle (formwork)
2 Concrete piping 11 Vibration formwork (peripheral part and vibration part)
12 Blow-up port (concrete piping connection port)
13 Cushion rubber (vibration isolation means)
14 Vibrator (vibration means)

Claims (2)

Of the formwork , it is a secondary lining concrete placing method for placing concrete while vibrating the peripheral part of the concrete pipe connection port provided at the top end ,
A secondary lining concrete placing method , wherein the peripheral portion is separated from a formwork body and a pipe connection port, and connected to the formwork body and the concrete injection hole so as to vibrate through a vibration isolating means .   A formwork used for placing secondary lining concrete, a part of the formwork, a vibration part that is connected to the formwork body through a vibration isolating means so as to vibrate, and penetrates the vibration part A formwork comprising: a pipe connection port that is provided and holds a concrete pipe via a vibration isolating means; and an excitation means that vibrates the vibration part.

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